WO2025068796A1

WO2025068796A1 - Agricultural analysis system and calibration methods thereof

Info

Publication number: WO2025068796A1
Application number: PCT/IB2024/058338
Authority: WO
Inventors: Michael Molter; Joshua SEELYE
Original assignee: Precision Planting LLC
Current assignee: Precision Planting LLC
Priority date: 2023-09-29
Filing date: 2024-08-28
Publication date: 2025-04-03
Anticipated expiration: 2026-03-29

Abstract

Systems, apparatuses, and methods for calibrating an agricultural analysis system are disclosed herein. In accordance with an aspect of the disclosure, provided is a method for utilizing an instrument adapted for analyzing an agricultural sample, the method comprising continuously providing (e.g., delivering) a calibration stream to the instrument adapted for analyzing an agricultural sample, the calibration stream having a composition that changes over a period of time.

Description

AGRICULTURAL ANALYSIS SYSTEM AND CALIBRATION METHODS THEREOF

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application Nos. 63/586726, filed 29 September 2023; 63/586955, filed 29 September 2023; 63/586966, filed 29 September 2023, all of which are incorporated herein by reference in their entireties.

BACKGROUND

[0002] The present invention relates generally to agricultural sampling and analysis, and more particularly to an agricultural sample processing and analysis system for analyzing soil and other types of agricultural related samples using plasma discharge spectroscopy.

[0003] Periodic soil testing is an important aspect of the agricultural arts. Test results provide valuable information on the chemical makeup of the soil such as plant-available nutrients and other important properties (e.g. levels of calcium, magnesium, phosphorous, potassium, pH, etc.) so that various amendments may be added to the soil to maximize the quality and quantity of crop production.

[0004] In some existing soil sampling processes, collected samples are dried, ground, water is added, and then filtered to obtain a soil slurry suitable for analysis. Extractant is added to the slurry to pull out various plant available nutrients (analytes). The slurry is then analyzed to ascertain the levels of the various plant available nutrients so that soil amendments may be made where necessary to replenish depleted nutrients in certain regions of the agricultural planting field.

[0005] Improvements in processing and analyzing agricultural samples such as soil, vegetation, manure, and others are desired.

BRIEF SUMMARY

[0006] This summary is intended merely to introduce a simplified summary of some aspects of one or more implementations of the present disclosure. Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. This summary is not an extensive overview, nor is it intended to identify key or critical elements of the present teachings, nor to delineate the scope of the disclosure. Rather, its purpose is merely to present one or more concepts in simplified form as a prelude to the detailed description and brief description of the drawings provided below.

[0007] Aspects of the disclosure are generally directed to systems, apparatuses, and methods for calibrating an agricultural analysis system. In accordance with an aspect of the disclosure, provided is a method for utilizing an instrument adapted for analyzing an agricultural sample, the method comprising continuously providing (e.g., delivering) a calibration stream to the instrument adapted for analyzing an agricultural sample, the calibration stream having a composition that changes over a period of time.

[0008] According to another aspect, provided is a method for calibrating an instrument adapted for analyzing an agricultural sample. The method may comprise continuously providing (e.g., delivering) a calibration stream to the instrument adapted for analyzing an agricultural sample, the calibration stream having a composition that changes over a period of time; evaluating the composition of calibration stream over at least a portion of the period of time, wherein at the start of the evaluated period of time the composition of the calibration stream is free of a standard sample and comprises the agricultural sample and the diluent, and wherein at the conclusion of the evaluated period of time the composition of the calibration stream at comprises the agricultural sample, a standard sample, and optionally a diluent; determining a detected rate of change of the composition of the calibration stream; identifying when the detected rate of change of the composition is substantially constant; optionally, determining a value of the detected rate of change of the composition when the rate of change of the composition is substantially constant or constant; determining a detected background value based on assessing the calibration stream when the calibration stream is free of the standard sample; and calibrating the instrument using the detected background value and the value of the detected rate of change of the composition when the rate of change of the composition is substantially constant or constant.

[0009] In accordance with a further aspect, a system is provided for calibrating an instrument adapted for analyzing an agricultural sample. The system typically includes a plurality of pumps configured to provide a calibration stream having a composition that changes over a period of time to a detector; and a plasma torch device comprising a plasma chamber and a plasma torch disposed at least partially in the plasma chamber, the plasma torch being fluidly coupled to the plurality of the pumps.

BRIEF DESCRIPTION OF THE DRAWINGS [0010] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein like elements are labeled similarly and in which:

[0011] FIG. 1 is a high-level schematic diagram showing steps for generating a plasma from an agricultural sample and measuring an analyte of agricultural interest according to one embodiment of an agricultural sample process and analysis system according to the present disclosure;

[0012] FIG. 2 is a schematic system diagram of a programmable processor-based central processing unit (CPU) or system controller for controlling the systems and apparatuses disclosed herein;

[0013] FIG. 3 is a schematic flow diagram showing a flow network formed by internal flow passages in a sample analysis apparatus for processing the agricultural sample;

[0014] FIG. 4 is schematic diagram showing a plurality of flow control manifold blocks and exemplary arrangement of diaphragm valves of the flow network therein;

[0015] FIG. 5 is a first perspective view of the agricultural sample analysis apparatus of the system operable to process and analyze a flowable sample fluid;

[0016] FIG. 6 is a second perspective view thereof;

[0017] FIG. 7 is a third perspective view thereof;

[0018] FIG. 8 is a fourth perspective view thereof;

[0019] FIG. 9 is a fifth perspective view thereof;

[0020] FIG. 10 is a sixth perspective view thereof;

[0021] FIG. 11 is a seventh perspective view thereof;

[0022] FIG. 12 is an eight perspective view thereof;

[0023] FIG. 13 is a first side elevation view thereof;

[0024] FIG. 14 is a second side elevation view thereof;

[0025] FIG. 15 is a rear elevation view thereof;

[0026] FIG. 16 is a front elevation view thereof;

[0027] FIG. 17 is a top view thereof;

[0028] FIG. 18 is a bottom view thereof;

[0029] FIG. 19 is a first vertical cross sectional view thereof;

[0030] FIG. 20 is an enlarged detail from FIG. 19;

[0031] FIG. 21 is a second vertical cross sectional view thereof;

[0032] FIG. 22 is an enlarged detail from FIG. 21; [0033] FIG. 23 is a phantom perspective view of the agricultural sample analysis apparatus showing internal details thereof;

[0034] FIG. 24 is an enlarged detail from FIG. 23 showing an assemblage and coupling of the flow control manifold blocks;

[0035] FIG. 25 is an exploded perspective view showing one of a plurality of diaphragm-operated hybrid pumps of the apparatus having an integrally incorporated pilot fluid drive system which operates the diaphragm to pump a process fluid;

[0036] FIG. 26 is a cross-sectional perspective view of the pump body of the hybrid pump of FIG. 25;

[0037] FIG. 27 is a first perspective view of the sample fluid manifold block showing internal flow passages and diaphragm pumping cavity;

[0038] FIG. 28 is a second perspective view thereof showing an opposite side of the sample fluid manifold block;

[0039] FIG. 29 is a perspective view of a mixing manifold block which receives process fluids from the hybrid pumps;

[0040] FIG. 30 is a top perspective view of the plasma torch device of the agricultural sample analysis apparatus which generates a plasma from a sample fluid for measurement of an analyte of agricultural interest by the spectrometer;

[0041] FIG. 31 is a first bottom perspective view thereof;

[0042] FIG. 32 is a second bottom perspective view thereof;

[0043] FIG. 33 is a front elevation view thereof;

[0044] FIG. 34 is a rear elevation view thereof;

[0045] FIG. 35 is a first side elevation view thereof;

[0046] FIG. 36 is a second elevation view thereof;

[0047] FIG. 37 is a first vertical cross sectional view thereof;

[0048] FIG. 38 is a second vertical cross sectional view thereof;

[0049] FIG. 39 is first vertical cross sectional view of a second embodiment of the diaphragm- operated hybrid pump including a pressure balanced seal system for the pilot fluid drive system;

[0050] FIG. 40 is a second vertical cross sectional view thereof;

[0051] FIG. 41 is a cross sectional view of an air removal device usable with the agricultural sample analysis apparatus of FIG. 5; [0052] FIG. 42 is a first perspective view thereof;

[0053] FIG. 43 is a second perspective view thereof;

[0054] FIG. 44 is a first exploded perspective view thereof;

[0055] FIG. 45 is a second exploded perspective view thereof;

[0056] FIG. 46 is a first side view thereof;

[0057] FIG. 47 is a top view thereof;

[0058] FIG. 48 is a second side view thereof;

[0059] FIG. 49 is a side cross sectional view thereof;

[0060] FIG. 50 is a flow chart of a non-limiting, exemplary method according to an aspect of the invention;

[0061] FIG. 51 is a flow chart of another non-limiting, exemplary method in accordance with an aspect of the invention; and

[0062] FIG. 52 is a flow chart of a non-limiting example of a process of calibrating a non-limiting, example system described herein in accordance with an aspect of the invention.

[0063] All drawings are not necessarily to scale. Components numbered and appearing in one figure but appearing un-numbered in other figures are the same unless expressly noted otherwise. A reference herein to a whole figure number which appears in multiple figures bearing the same whole number but with different alphabetical suffixes shall be constructed as a general refer to all of those figures unless expressly noted otherwise.

DETAILED DESCRIPTION

[0064] The features and benefits of the invention are illustrated and described herein by reference to exemplary (“example”) embodiments. This description of exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. Accordingly, the disclosure expressly should not be limited to such exemplary embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features.

[0065] In the description of embodiments disclosed herein, any reference to direction or orientation is merely intended for convenience of description and is not intended in any way to limit the scope of the present invention. Relative terms such as "lower," "upper," “horizontal,” “vertical,”, “above,” “below,” “up,” “down,” “top” and “bottom” as well as derivative thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description only and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “attached,” “affixed,” “connected,” “coupled,” “interconnected,” and similar refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise.

[0066] As used throughout, any ranges disclosed herein are used as shorthand for describing each and every value that is within the range. Any value within the range can be selected as the terminus of the range. In addition, all references cited herein are hereby incorporated by referenced in their entireties. In the event of a conflict in a definition in the present disclosure and that of a cited reference, the present disclosure controls.

[0067] Aspects of the disclosure are generally directed to systems, apparatuses, and methods for calibrating an agricultural analysis system. The inventors discovered that certain systems and methods disclosed herein advantageously enable an automated calibration of an agricultural analysis system that is significantly faster than conventional standard addition methods. Additionally, certain embodiments provide methods of calibration that overcome the problem of calibration drift.

[0068] In accordance with an aspect of the disclosure, provided is a method 1000 for utilizing an instrument adapted for analyzing an agricultural sample. Referring to FIG. 1, method 1000 typically comprises the step of continuously providing a calibration stream to the instrument adapted for analyzing an agricultural sample (see step 1100). Referring to FIG. 2, method 2000 typically includes continuously providing (e.g., delivering) a calibration stream to the instrument adapted for analyzing an agricultural sample, the calibration stream having a composition that changes over a period of time (see step 2100); evaluating the composition of calibration stream over at least a portion of the period of time, wherein at the start of the evaluated period of time the composition of the calibration stream is free of a standard sample and comprises the agricultural sample and the diluent, and wherein at the conclusion of the evaluated period of time the composition of the calibration stream at comprises the agricultural sample, a standard sample, and optionally a diluent (see step 2200); determining a detected rate of change of the composition of the calibration stream (see step 2300); identifying when the detected rate of change of the composition is substantially constant (see step 2400); optionally, determining a value of the detected rate of change of the composition when the rate of change of the composition is substantially constant or constant (see step 2500); determining a detected background value based on assessing the calibration stream when the calibration stream is free of the standard sample (see step 2600); and calibrating the instrument using the detected background value and the value of the detected rate of change of the composition when the rate of change of the composition is substantially constant or constant (see step 2700).

[0069] In step 1100 and/or 2100, a calibration stream is continuously provided (e.g., delivering) to an instrument adapted for analyzing an agricultural sample. The calibration stream has a composition that changes over a period of time. For instance, the calibration stream may have one or more components that increase over the period of time and/or one or more components that decreases over the period of time, such that the composition of the calibration stream changes over the period of time.

[0070] The period of time may be the period of time that the calibration stream is being provided to the instrument adapted for analyzing an agricultural sample. The period of time may be the evaluated period of time (e.g., the period of time for which the calibration stream is being analyzed for calibrating the instrument adapted for analyzing an agricultural sample) in any and/or all of the embodiments described herein. As seen in FIG. 2, the method may, in some embodiments, comprise evaluating the composition of calibration stream over at least a portion of the period of time (see step 2100).

[0071] The period and/or the evaluated period of time may be about 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, 1 minutes, 2 minutes, 4 minutes, 6 minutes, 8 minutes, 10 minutes, or any range formed therefrom. For example, the period of time and/or evaluated period of time may be from about 10 seconds to about 10 minutes, about 10 seconds to about 8 minutes, about 10 seconds to about 6 minutes, about 10 seconds to about 4 minutes, about 10 seconds to about 2 minutes, about 10 seconds to about 1 minute, about 10 seconds to about 40 seconds, about 10 seconds to about 30 seconds, about 10 seconds to about 20 seconds; from about 20 seconds to about 10 minutes, about 20 seconds to about 8 minutes, about 20 seconds to about 6 minutes, about 20 seconds to about 4 minutes, about 20 seconds to about 2 minutes, about 20 seconds to about 1 minute, about 20 seconds to about 40 seconds, about 20 seconds to about 30 seconds; from about 30 seconds to about 10 minutes, about 30 seconds to about 8 minutes, about 30 seconds to about 6 minutes, about 30 seconds to about 4 minutes, about 30 seconds to about 2 minutes, about 30 seconds to about 1 minute, about 30 seconds to about 45 seconds; from about 45 seconds to about 10 minutes, about 45 seconds to about 8 minutes, about 45 seconds to about 6 minutes, about 45 seconds to about 4 minutes, about 45 seconds to about 2 minutes, about 45 seconds to about 75 seconds; from about 1 to about 10 minutes, about 1 to about 8 minutes, about 1 to about 6 minutes, about 1 to about 4 minutes, about 1 to about 2 minutes; from about 2 to about 10 minutes, about 2 to about 8 minutes, about 2 to about 6 minutes, about 2 to about 4 minutes; from about 4 to about 10 minutes, about 4 to about 8 minutes, about 4 to about 6 minutes; from about 6 to about 10 minutes, about 6 to about 8 minutes, about 8 to about 10 minutes, or any range or subrange thereof. [0072] At the start of the period of time, the calibration stream may have a composition comprising an agricultural sample and a diluent. The stream may, in some embodiments, comprise a standard sample at the start of the period of time, e.g., in conjunction with an agricultural sample and a diluent. For example, the calibration stream may have a composition comprising from about 10 to about 60 vol.% of an agricultural sample, relative to the volume of the provided calibration stream. In some embodiments, the amount of agricultural sample in the calibration stream at the start of the period of time is about 10 to about 60 vol.%, about 10 to about 55 vol.%, about 10 to about 50 vol.%, about 10 to about 45 vol.%, about 10 to about 40 vol.%, about 10 to about 35 vol.%, about 10 to about 30 vol.%, about 10 to about 25 vol.%, about 10 to about 20 vol.%, about 10 to about 15 vol.%; from about 10 to about 60 vol.%, about 10 to about 55 vol.%, about 10 to about 50 vol.%, about 10 to about 45 vol.%, about 10 to about 40 vol.%, about 10 to about 35 vol.%, about 10 to about 30 vol.%, about 10 to about 25 vol.%, about 10 to about 20 vol.%, about 10 to about 15 vol.%; from about 15 to about 60 vol.%, about 15 to about 55 vol.%, about 15 to about 50 vol.%, about 15 to about 45 vol.%, about 15 to about 40 vol.%, about 15 to about 35 vol.%, about 15 to about 30 vol.%, about 15 to about 25 vol.%, about 15 to about 20 vol.%; from about 20 to about 60 vol.%, about 20 to about 55 vol.%, about 20 to about 50 vol.%, about 20 to about 45 vol.%, about 20 to about 40 vol.%, about 20 to about 35 vol.%, about 20 to about 30 vol.%, about 20 to about 25 vol.%; from about 25 to about 60 vol.%, about 25 to about 55 vol.%, about 25 to about 50 vol.%, about 25 to about 45 vol.%, about 25 to about 40 vol.%, about 25 to about 35 vol.%, about 25 to about 30 vol.%; from about 30 to about 60 vol.%, about 30 to about 55 vol.%, about 30 to about 50 vol.%, about 30 to about 45 vol.%, about 30 to about 40 vol.%, about 30 to about 35 vol.%; from about 40 to about 60 vol.%, about 40 to about 55 vol.%, about 40 to about 50 vol.%; from about 50 to about 60 vol.%, about 50 to about 55 vol.% or any range or subrange thereof, relative to the volume of the provided calibration stream.

[0073] The calibration stream may have a composition comprising from about 10 to about 90 vol.% of a diluent, relative to the volume of the provided calibration stream. In some embodiments, the amount of diluent in the calibration stream at the start of the period of time is from about 10 to about 90 vol.%, about 10 to about 85 vol.%, about 10 to about 80 vol.%, about 10 to about 75 vol.%, about 10 to about 70 vol.%, about 10 to about 65 vol.%, about 10 to about 55 vol.%, about 10 to about 45 vol.%, about 10 to about 35 vol.%, about 10 to about 25 vol.%; from about 25 to about 90 vol.%, about 25 to about 85 vol.%, about 25 to about 80 vol.%, about 25 to about 75 vol.%, about 25 to about 70 vol.%, about 25 to about 65 vol.%, about 25 to about 55 vol.%, about 25 to about 45 vol.%, about 25 to about 35 vol.%; from about 40 to about 90 vol.%, about 40 to about 85 vol.%, about 40 to about 80 vol.%, about 40 to about 75 vol.%, about 40 to about 70 vol.%, about 40 to about 65 vol.%, about 40 to about 55 vol.%; from about 55 to about 90 vol.%, about 55 to about 85 vol.%, about 55 to about 80 vol.%, about 55 to about 75 vol.%, about 55 to about 70 vol.%, about 55 to about 65 vol.%; from about 65 to about 90 vol.%, about 65 to about 85 vol.%, about 65 to about 80 vol.%, about 65 to about 75 vol.%; from about 70 to about 90 vol.%, about 70 to about 85 vol.%, about 70 to about 80 vol.%, about 70 to about 75 vol.%; from about 75 to about 90 vol.%, about 75 to about 85 vol.%, about 75 to about 80 vol.%; from about 80 to about 90 vol.%, about 80 to about 85 vol.%, about 85 to about 90 vol.%, relative to the volume of the provided calibration stream.

[0074] Although the calibration stream may comprise or be free of the standard sample at the start of the period of time, the calibration stream may comprise from about 1 to about 90 vol.% of the standard sample, relative to the volume of the provided calibration stream. For example, the standard sample may be present in the calibration stream at the start of the period of time in an amount from about 0 to about 90 vol.%, about 0 to about 70 vol.%, about 0 to about 50 vol.%, about 0 to about 30 vol.%, about 0 to about 20 vol.%, about 0 to about 10 vol.%, about 0 to about 5 vol.%, about 0 to about 1 vol.%; from about 1 to about 70 vol.%, about 1 to about 50 vol.%, about 1 to about 30 vol.%, about 1 to about 20 vol.%, about 1 to about 10 vol.%, about 1 to about 5 vol.%, about 0.1 to about 1 vol.%; from about 5 to about 90 vol.%, about 5 to about 50 vol.%, about 5 to about 30 vol.%, about 5 to about 20 vol.%, about 5 to about 10 vol.%; from about 10 to about 90 vol.%, about 10 to about 70 vol.%, about 10 to about 50 vol.%, about 10 to about 40 vol.%, about 10 to about 30 vol.%; from about 30 to about 90 vol.%, about 30 to about 70 vol.%, about 30 to about 50 vol.%, about 30 to about 40 vol.%; from about 50 to about 90 vol.%, about 50 to about 80 vol.%, about 50 to about 70 vol.%; from about 70 to about 90 vol.%, about 70 to about 80 vol.%, or about 80 to about 90 vol.%, relative to the volume of the provided calibration stream.

[0075] In some embodiments, at the start of the period of time (e.g., the evaluated period of time), the calibration stream has a composition comprising about 0 to about 90 vol.%, relative to the volume of the provided calibration stream, of standard sample; from 10 to about 90 vol.%, relative to the volume of the provided calibration stream, of the diluent; and from about 10 to about 60 vol.%, relative to the volume of the provided calibration stream, of an agricultural sample.

[0076] The method may include determining an averaged measurement of the constant value of the agricultural sample (or an analyte thereof) in the calibration stream at the start of the period of time and/or before the composition of the calibration stream is varied.

[0077] The method typically comprises varying the calibration stream as the calibration stream is provided to the instrument adapted for analyzing the agricultural sample. The composition of the calibration stream may vary by an increase or decrease in the amount of the agricultural sample, the amount of diluent, and/or the amount of a standard sample in the calibration stream. In at least one embodiment, the amount of the diluent in the calibration steam decreases over the period of time as the calibration stream is provided to the instrument adapted for analyzing an agricultural sample. Additionally or alternatively, the amount of the standard sample in the calibration steam may increase over the period of time as the calibration stream is provided to the instrument adapted for analyzing an agricultural sample.

[0078] Preferably, the composition of the calibration stream continuously changes over the evaluated period of time. In some embodiments, however, the composition of the calibration stream changes in a stepwise manner over the evaluated period of time. The composition of the calibration stream may change continuously over the evaluated period of time at consistent rate of change. For example, the increase or decrease in the amount of the agricultural sample, the amount of diluent, and/or the amount of a standard sample in the calibration stream may change continuously over the evaluated period of time at consistent rate of change. In some embodiments, the amount of a standard sample in the calibration stream continuously increases over the evaluated period of time at consistent rate of change. Additionally or alternatively, in some embodiments, the amount of a diluent in the calibration stream continuously decreases over the evaluated period of time at consistent rate of change.

[0079] In some embodiments, the amount of the agricultural sample in the calibration steam remains substantially constant or constant over the period of time. For example, the amount of agricultural sample in the calibration stream may vary by about 10% or less, about 8% or less, about 6% or less, about 5% or less, about 4% or less, about 3% or less, about 2% or less, about 1% or less, about 0.5% or less, over the period of time. In at least one preferred embodiment, the period of time is the evaluated period of time. As noted above, the period of time may be about 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, 1 minutes, 2 minutes, 4 minutes, 6 minutes, 8 minutes, 10 minutes, or any range formed therefrom.

[0080] The calibration stream may have a composition comprising an agricultural sample, a standard sample, and optionally a diluent at the conclusion of the period of time (e.g., the evaluated period of time). For instance, the calibration stream may have a composition comprising about 50 to about 90 vol.% of standard sample, relative to the volume of the provided calibration stream at the conclusion of the period of time. In some instances, the amount of the standard sample present in the calibration stream at the conclusion of the period of time is from about 50 to about 90 vol.%, about 50 to about 85 vol.%, about 50 to about 80 vol.%, about 50 to about 75 vol.%, about 50 to about 70 vol.%, about 50 to about 65 vol.%; from about 55 to about 90 vol.%, about 55 to about 85 vol.%, about 55 to about 80 vol.%, about 55 to about 75 vol.%, about 55 to about 70 vol.%, about 55 to about 65 vol.%; from about 60 to about 90 vol.%, about 60 to about 85 vol.%, about 60 to about 80 vol.%, about 60 to about 75 vol.%; from about 65 to about 90 vol.%, about 65 to about 85 vol.%, about 65 to about 80 vol.%, about 65 to about 75 vol.%; from about 70 to about 90 vol.%, about 70 to about 85 vol.%, about 70 to about 80 vol.%, about 70 to about 75 vol.%; from about 75 to about 90 vol.%, about 75 to about 85 vol.%, about 75 to about 80 vol.%; from about 80 to about 90 vol.%, about 80 to about 85 vol.%, about 85 to about 90 vol.%, or any range or subrange thereof, relative to the volume of the provided calibration stream.

[0081] Additionally or alternatively, the calibration stream may comprise from 0 to about 50 vol.%, relative to the volume of the provided calibration stream, of the diluent at the conclusion of the period of time. At the conclusion of the period of time, the calibration stream may be substantially free of or free of diluent. In some instances, the amount of the diluent present in the calibration stream at the conclusion of the period of time may be from 0 to about 50 vol.%, 0 to about 40 vol.%, 0 to about 30 vol.%, 0 to about 20 vol.%, 0 to about 10 vol.%, 0 to about 8 vol.%, 0 to about 6 vol.%, 0 to about 4 vol.%, 0 to about 2 vol.%, 0 to about 1 vol.%, 0 to about 0.5 vol.%, 0 to about 0.1 vol.%; from about 1 to about 50 vol.%, about 1 to about 40 vol.%, about 1 to about 30 vol.%, about 1 to about 20 vol.%, about 1 to about 10 vol.%, about 1 to about 8 vol.%, about 1 to about 6 vol.%, about 1 to about 4 vol.%, about 1 to about 2 vol.%; from about 3 to about 50 vol.%, about 3 to about 40 vol.%, about 3 to about 30 vol.%, about 3 to about 20 vol.%, about 3 to about 10 vol.%, about 3 to about 8 vol.%, about 3 to about 6 vol.%, about 3 to about 4 vol.%; from about 6 to about 50 vol.%, about 6 to about 40 vol.%, about 6 to about 30 vol.%, about 6 to about 20 vol.%, about 6 to about 10 vol.%, about 6 to about 8 vol.%; from about 10 to about 50 vol.%, about 10 to about 40 vol.%, about 10 to about 30 vol.%, about 10 to about 20 vol.%; from about 20 to about 50 vol.%, about 20 to about 40 vol.%, about 20 to about 30 vol.%; from about 30 to about 50 vol.%, about 30 to about 40 vol.%, about 40 to about 50 vol.%, or any range or subrange thereof, relative to the volume of the provided calibration stream.

[0082] The amount of agricultural sample in the calibration stream at the conclusion of the period of time may be about 10 to about 60 vol.%, about 10 to about 55 vol.%, about 10 to about 50 vol.%, about 10 to about 45 vol.%, about 10 to about 40 vol.%, about 10 to about 35 vol.%, about 10 to about 30 vol.%, about 10 to about 25 vol.%, about 10 to about 20 vol.%, about 10 to about 15 vol.%; from about 10 to about 60 vol.%, about 10 to about 55 vol.%, about 10 to about 50 vol.%, about 10 to about 45 vol.%, about 10 to about 40 vol.%, about 10 to about 35 vol.%, about 10 to about 30 vol.%, about 10 to about 25 vol.%, about 10 to about 20 vol.%, about 10 to about 15 vol.%; from about 15 to about 60 vol.%, about 15 to about 55 vol.%, about 15 to about 50 vol.%, about 15 to about 45 vol.%, about 15 to about 40 vol.%, about 15 to about 35 vol.%, about 15 to about 30 vol.%, about 15 to about 25 vol.%, about 15 to about 20 vol.%; from about 20 to about 60 vol.%, about 20 to about 55 vol.%, about 20 to about 50 vol.%, about 20 to about 45 vol.%, about 20 to about 40 vol.%, about 20 to about 35 vol.%, about 20 to about 30 vol.%, about 20 to about 25 vol.%; from about 25 to about 60 vol.%, about 25 to about 55 vol.%, about 25 to about 50 vol.%, about 25 to about 45 vol.%, about 25 to about 40 vol.%, about 25 to about 35 vol.%, about 25 to about 30 vol.%; from about 30 to about 60 vol.%, about 30 to about 55 vol.%, about 30 to about 50 vol.%, about 30 to about 45 vol.%, about 30 to about 40 vol.%, about 30 to about 35 vol.%; from about 40 to about 60 vol.%, about 40 to about 55 vol.%, about 40 to about 50 vol.%; from about 50 to about 60 vol.%, about 50 to about 55 vol.% or any range or subrange thereof, relative to the volume of the provided calibration stream.

[0083] In some embodiments, at the conclusion of the period of time (e.g., evaluated period of time), the calibration stream has a composition comprising about 50 to about 90 vol.%, relative to the volume of the provided calibration stream, of standard sample; from 0 to about 50 vol.%, relative to the volume of the provided calibration stream, of the diluent; and from about 10 to about 60 vol.%, relative to the volume of the provided calibration stream, of an agricultural sample. In least one embodiment, at the conclusion of the period of time (e.g., evaluated period of time), the calibration stream has a composition consisting of or consisting essentially of about 50 to about 90 vol.%, relative to the volume of the provided calibration stream, of standard sample; and from about 10 to about 60 vol.%, relative to the volume of the provided calibration stream, of an agricultural sample.

[0084] The calibration stream may have a flow rate that is substantially constant or constant over the period of time. In at least one preferred embodiment, the flow rate of the calibration stream provided to the instrument adapted for analyzing the agricultural sample is substantially constant or constant for the evaluated period of time. The flow rate of the composition may be substantially constant if the flow rate does not vary by more than ±10% over a period of, e.g., at least 1 second. For instance, the flow rate may be determined to be substantially constant if the flow rate of the composition varies by about 10% or less, about 8% or less, about 6% or less, about 4% or less, about 2% or less, about 1% or less, about 0.5% or less, or about 0.1% or less over a period of time of at least 1 second, e.g., about 2 or more seconds, about 5 or more seconds, about 10 or more seconds, about 15 or more seconds, about 20 or more seconds, about 30 or more seconds, about 40 or more seconds, about 50 or more seconds, about 60 or more seconds, about 75 or more seconds, about 90 or more seconds, about 105 or more seconds, or about 120 or more seconds. In some embodiments, the period of time used for assessing if the flow rate is substantially constant or constant is from about 1 to about 60 seconds, about 1 to about 30 seconds, about 1 to about 20 seconds, about 1 to about 10 seconds, about 1 to about 8 seconds, about 1 to about 6 seconds, about

1 to about 5 seconds, about 1 to about 4 seconds, about 1 to about 3 seconds, about 1 to about 2 seconds; from about 2 to about 60 seconds, about 2 to about 30 seconds, about 2 to about 20 seconds, about 2 to about 10 seconds, about 2 to about 8 seconds, about 2 to about 6 seconds, about

2 to about 5 seconds, about 2 to about 4 seconds, about 2 to about 3 seconds; from about 3 to about 60 seconds, about 3 to about 30 seconds, about 3 to about 20 seconds, about 3 to about 10 seconds, about 3 to about 8 seconds, about 3 to about 6 seconds, about 3 to about 5 seconds, about 3 to about 4 seconds; from about 5 to about 60 seconds, about 5 to about 30 seconds, about 5 to about 20 seconds, about 5 to about 10 seconds, about 5 to about 8 seconds, about 5 to about 6 seconds, or any range or subrange thereof.

[0085] The agricultural sample may include, or consist of, substances that are agricultural in nature, including without limitation as examples soil, vegetation, crop residue, manure, milk, or any other sample material of agricultural interest. In some embodiments, before the agricultural sample is provided to the instrument adapted for analyzing an agricultural sample, the agricultural sample may be reduced in size by grinding or other means and then optionally mixed with a carrier (e.g., water) to produce a sample slurry.

[0086] The agricultural sample may be a soil sample. The soil sample may be a soil slurry and/or a filtrate of the soil slurry. The soil slurry may be obtained by mixing and/or combining soil and water. For example, a sample of soil may be screened through a mesh and combined with water in a ratio of soil to water (weight : volume) of 1 :3 to produce a soil slurry. The soil slurry may be filtered to obtain a filtrate of the soil slurry. In some instances, the soil sample, soil slurry, and/or filtrate may include at least one soil particle, an extractant, a flocculant, and/or a carrier. The agricultural sample may comprise one or more analytes. In some instance, the one or more analytes may be analytes obtained from the soil sample or soil particles thereof, such as nutrients contained in the soil sample. The one or more analytes may be selected from, potassium, magnesium, calcium, sodium, cation exchange capacity, zinc, manganese, iron, copper, boron, soluble salts, aluminum, , molybdenum, and a combination of two more thereof. The agricultural sample may be a soil sample and comprises at least one soil particle and one or more analytes selected from potassium, magnesium, calcium, phosphorous, boron, nitrogen, sulfur, a salt thereof, an ion thereof, or a combination of two or more thereof.

[0087] In some cases, the agricultural sample may comprise at least one soil particle and a carrier. The at least one soil particle and the carrier may be present in a weight ratio of the at least one soil particle to the carrier of about 5: 1 to about 2:1, e.g., from about 4:1 to about 2: 1, from about 3: 1 to about 2:l, from about 5: l to about 3:l, from about 4: 1 to about 3: l, or any range thereof. In at least one embodiment, the agricultural sample has a weight ratio of the at least one soil particle to the carrier of about 3:1. [0088] The agricultural sample may be a plant and/or vegetation sample. The method may identify, determine, and/or assess one or more analytes in the plant and/or vegetation sample, wherein the one or more analytes is selected from phosphorus, potassium, magnesium, calcium, sodium, percent base saturation of cations, sulfur, zinc, manganese, iron, copper, boron, cobalt, molybdenum, selenium, and a combination of two or more thereof.

[0089] In some cases, the agricultural sample may be a manure sample comprising one or more analytes. The method may identify, determine, and/or assess one or more analytes in the plant and/or vegetation sample, wherein the one or more analytes is selected from, calcium, magnesium, sodium, iron, manganese, copper, zinc soluble salts, potash, calcium, cobalt, copper, iron, manganese, arsenic, lead, selenium, cadmium, chromium, mercury, nickel, sodium, molybdenum, zinc, and a combination of two or more thereof.

[0090] The agricultural sample may be selected from animal feeds in certain embodiments. The method may identify, determine, and/or assess one or more analytes in the animal feed selected from the group consisting of arsenic, lead, cadmium, antimony, mercury, calcium, calcium, magnesium, sodium, manganese, zinc, potassium, iron, copper (not applicable to premixes), an ion thereof, a salt thereof, and a combination of two or more thereof. The analytes in the soil agricultural sample may be a salt, such as sodium, calcium, magnesium, potassium, a salt thereof, a compound thereof, an ion thereof, or a combination thereof. In some embodiments, the analytes for analysis may be, e.g., NaCl, NaNCh, CaCh, Ca(NO3)2, MgCb, Mg(NCh)2, KC1, KNO3, or a combination thereof.

[0091] The agricultural sample may be chosen from forage samples. The method may identify, determine, and/or assess one or more analytes in the forage sample selected from copper, sodium, magnesium, potassium, zinc, iron, calcium, manganese, sodium, molybdenum, selenium, and a combination of two or more thereof.

[0092] The diluent may comprise water and an acid and/or salt thereof, such as nitric acid and/or a salt thereof or hydrochloric acid and/or a salt thereof. For example, the diluent may include nitric acid, hydrochloric acid, a salt thereof or a combination thereof in a molar concentration of about 0.05 to about 0.8 M, about 0.05 to about 0.6 M, about 0.05 to about 0.5 M, about 0.05 to about 0.4 M, about 0.05 to about 0.3 M, about 0.05 to about 0.2 M; from about 0.1 to about 0.8 M, about 0.1 to about 0.6 M, about 0.1 to about 0.5 M, about 0.1 to about 0.4 M, about 0.1 to about 0.3 M, about 0.1 to about 0.2 M; from about 0.2 to about 0.8 M, about 0.2 to about 0.6 M, about 0.2 to about 0.5 M, about 0.2 to about 0.4 M, about 0.2 to about 0.3 M; from about 0.3 to about 0.8 M, about 0.3 to about 0.6 M, about 0.3 to about 0.5 M, about 0.3 to about 0.4 M; from about 0.4 to about 0.8 M, about 0.4 to about 0.6 M, about 0.4 to about 0.5 M; from about 0.5 to about 0.8 M, about 0.5 to about 0.7 M, about 0.5 to about 0.7 M, or any range or subrange thereof. In some embodiments, the diluent comprises about 0.1 M HNO3, about 0.2 M HNO3, about 0.27 M HNO3, about 0.1 M HC1, about 0.2 M HC1, about 0.27 M HC1, about 0.5 M HN03, and/or about 0.5 M HC1. The diluent may be a solvent for the standard sample.

[0093] The standard sample may comprise a metal for use as a standard for assessing analytes in the agricultural sample. The metal for use as a standard may be selected from potassium, sodium, magnesium, calcium, copper, iron, manganese, lithium, rhodium, thallium, indium, an ion thereof, a salt thereof, and a combination of two or more thereof. In some instances, the metal for use as a standard may be selected from potassium, sodium, magnesium, calcium, copper, iron, manganese, an ion thereof, a salt thereof, and a combination of two or more thereof. Additionally or alternatively, the metal for use as a standard may be selected from lithium, rhodium, thallium, indium, an ion thereof, a salt thereof, and a combination of two or more thereof. In at least one embodiment, the metal for use as a standard is lithium, an ion thereof, and/or a salt thereof.

[0094] The method may include evaluating the composition of the calibration stream over at least a portion of the period of time (see step 2200 of FIG. 2). The evaluation of the calibration stream may comprise determining a detected rate of change of the composition of the calibration stream (see step 2300 of FIG. 2). The detected rate of change of the composition may be determined based on a rate of change of one or more analyte in the standard sample. For instance, the instrument adapted for analyzing an agricultural sample may determine a rate of change for the analyte(s) of the standard sample over a period of time, e.g., as the standard sample increases over such period of time. In certain embodiments, the instrument adapted for analyzing an agricultural sample may identify the amount of analyte of the standard sample in the calibration stream by turning a portion of the calibration stream into plasma and identifying the amount of certain analytes in the plasma formed from the calibration stream using an imaging device. For instance, the analyte of the standard sample may be selected from potassium, sodium, magnesium, calcium, copper, iron, manganese, lithium, rhodium, thallium, indium, an ion thereof, a salt thereof, and a combination of two or more thereof. In some embodiments, the analyte of the standard sample may be selected from potassium, sodium, magnesium, calcium, copper, iron, manganese, an ion thereof, a salt thereof, and a combination of two or more thereof. In further embodiments, the analyte of the standard sample may be selected from lithium, rhodium, thallium, indium, an ion thereof, a salt thereof, and a combination of two or more thereof.

[0095] In some embodiments, evaluating the calibration stream comprises identifying when the detected rate of change of the composition is substantially constant (see step 2400 of FIG. 2). The rate of change of the composition may, in some embodiments, be identified as being substantially constant when the detected rate of change of the standard sample, the detected rate of change of the diluent, one or more analyte thereof, or a combination of two or more thereof is substantially constant. In some embodiments, the method includes identifying when the detected rate of change of the standard sample, or an analyte thereof is substantially constant or constant. Additionally or alternatively, the method may include identifying when the detected rate of change of the agricultural sample, or an analyte thereof is substantially constant or constant.

[0096] The detected rate of change of the composition, the diluent, and/or the standard sample may be substantially constant if the detected rate of change of the composition does not vary by more than ±10% over a period of at least 1 second. For example, the detected rate of change may be determined to be substantially constant if the detected rate of change of the composition varies by about 10% or less, about 8% or less, about 6% or less, about 4% or less, about 2% or less, about 1% or less, about 0.5% or less, or about 0.1% or less over a period of at least 1 second, e.g., about 2 or more seconds, about 5 or more seconds, about 10 or more seconds, about 15 or more seconds, about 20 or more seconds, about 30 or more seconds, about 40 or more seconds, about 50 or more seconds, about 60 or more seconds, about 75 or more seconds, about 90 or more seconds, about 105 or more seconds, or about 120 or more seconds. In some embodiments, evaluating the calibration stream comprises identifying when the detected rate of change of the composition is constant over at least 1 second, e.g., about 2 or more seconds, about 5 or more seconds, about 10 or more seconds, about 15 or more seconds, about 20 or more seconds, about 30 or more seconds, about 40 or more seconds, about 50 or more seconds, about 60 or more seconds, about 75 or more seconds, about 90 or more seconds, about 105 or more seconds, or about 120 or more seconds.

[0097] The value of the detected rate of change of the composition may be determined when the rate of change of the composition is substantially constant or is constant. For instance, the method for calibrating the instrument adapted for analyzing an agricultural sample may comprise evaluating the calibration stream including determining a value of the detected rate of change of the composition (e.g., assessed based on the rate of change of one or more analytes of the agricultural sample in the calibration stream) when the rate of change of the composition is substantially constant or constant (see step 2500 of FIG. 2). The rate of change of the composition may be determined as discussed above.

[0098] The method may determine the concentration of one or more analytes of the agricultural sample (such as those disclosed herein) at one or more points in time and/or the detector’s rate of change, when the detected rate of change of the composition of the calibration stream is determined to be constant or substantially constant. The method may also include determining a detected background value based on assessing the calibration stream when the calibration stream is free of the standard sample (see step 2600 of FIG. 2). The background value may be detected by identifying and/or assessing the amount of one or more analytes in the calibration stream. For instance, the instrument adapted for analyzing an agricultural sample may ionize a portion of the calibration stream (which is preferably free of the standard sample) to form a plasma from such portion, identify the amount of certain analyte(s) in the plasma using an imaging device, and detect the background value of the calibration stream from the identified analytes.

[0099] Using the detected background value and the value of the detected rate of change of the composition, the instrument adapted for analyzing an agricultural sample may be calibrated (see step 2700). For instance, the method may further include calibrating the instrument using the detected background value and the value of the detected rate of change of the composition when the rate of change of the composition is substantially constant or is constant. The method may advantageously calibrate the instrument adapted for analyzing an agricultural sample and analyze the agricultural sample in a single run, e.g., without stopping the continuously provided calibration stream to the instrument adapted for analyzing an agricultural sample.

[0100] In accordance with another aspect of the disclosure, a system is provided that can calibrate an instrument adapted for analyzing an agricultural sample. FIGS. 1-49 show various aspects and features of one embodiment of an agricultural sample analysis apparatus 100 of the sample processing and analysis system disclosed herein. The apparatus receives a sample fluid for analysis, which may be but is not limited to a prepared sample slurry in one non-limiting embodiment comprising a mixture of agricultural solids and water. In one embodiment, the apparatus may be configured and operable to add extractant to the sample fluid to draw out the agricultural analyte of interest (e.g., plant available nutrient or other), mix the extractant and sample fluid, and then analyze the sample fluid-extractant mixture via plasma glow spectrometry in a single self-supported unit.

[0101] The sample fluid may be any fluid derived having agricultural-related origins (examples of which are described elsewhere herein) and which contains an analyte of agricultural interest and value to be measured. Examples of sample fluids discussed herein may be directed to sample slurries formed from a mixture of water and an agricultural solids sample such as soil. However, the systems and apparatuses described herein are not limited to use with slurries which represents only one type of sample fluid which can be processed and analyzed.

[0102] Sample analysis apparatus 100 in one embodiment generally comprises a spectrometer 300, plasma torch device 200, and a fluid handling system comprising a fluidly interconnected flow network 101 formed by plural flow passages 102 which fluidly couple together pumps and valving for controlling and directing the flow of sample fluid (e.g., slurry or other), calibration standard (liquid solution for calibrating the spectrometer), water for cleaning the pump chambers between sample fluid analysis runs, and diluent.

[0103] In one embodiment, an assemblage of diaphragm-operated hybrid pumps may be provided including diluent pump Ml, standards pump M2, mixing pump M3, and sample pump M4. The pumps and associated valving are fluidly coupled to the flow network 101 shown in FIG. 3, as further described herein.

[0104] Diluent pump Ml is operable to pump a diluent (e.g., nitric acid or other) to the plasma torch device 200 for use in conjunction with measuring the analyte in the sample fluid such as a slurry. Standards pump M2 is operable to pump a standards solution which contains a known concentration of the analyte of interest to the plasma torch device 200 for use in calibrating the spectrometer. Mixing pump M3 is operable to exchange flow back and forth with the sample pump M4 for mixing the sample slurry with extractant and additional water if needed, as further described herein. Sample pump M4 is operable to pump the agricultural sample slurry mixture (including the extractant and any additional dilution water) to plasma torch device 200. The sample slurry may be passed through a filter upstream of the sample pump M4 (which in turn is upstream of the plasma torch) in accordance with any of the filters disclosed for the purpose of sizing the slurry as disclosed in the commonly-owned patent application publications referenced herein.

[0105] Each of the diaphragm pumps M1-M4 inclusive in one embodiment may be a pilot fluid actuated diaphragm pump operable to pump the intended fluid such as agricultural sample slurry, water, standard (standard solution), diluent, or another fluid. Each pump comprises a pump body 110. The pump bodies may have a monolithic structure in one embodiment as shown and are formed of a suitable material which may be metallic or plastic in some embodiments. The pumps may be similar or identical in construction and are differentiated by the purpose and locations of the fluid inlet and outlets of each. The pump bodies comprise a top 105, bottom 106, and plurality of intersecting side surfaces 107 extending along a pump axis PA between the top and bottom. The pump bodies 110 in one embodiment may be formed of a solid block of material such as a suitable metal or preferably plastic. Various internal structures of the pump bodies described herein may be formed as a negative features (i.e. openings) integrally formed in the body by suitable fabrication and machining methods such as without limitation casting, molding, 3D printing, boring, etc. to name a few depending on the type of material selected.

[0106] Pumps M1-M4 each comprise a recessed pumping cavity 112 formed on one of the outer surfaces 107 of the pump bodies and which is designated herein as an active outer surface 107a which is associated with the actual diaphragm-action pumping mechanism of the pumps (see, e.g., exploded pump view FIG. 25). Pumping chamber 112 comprises an outwardly open concavity formed in active outer surface 107a. A resiliently deformable diaphragm 111 formed of a suitable elastomeric or rubber material is disposed at and over the pumping cavity 112 and fluidly seals the cavity on the inward facing side, which is the pilot side. The opposite outward facing side of diaphragm 111 constitutes the working side which is in direct wetted contact with the process fluid such as slurry, standard solution, diluent, water, or other depending on which pump is involved. Diaphragm 111 may be generally disk-shaped in one embodiment having a circular or oval configuration. A plurality of anti-stall grooves 113 may be recessed into the arcuately curved bottom wall 114 of the pumping cavity to prevent the diaphragm from adhering and getting stuck on the surface when the diaphragm is actuated and deformed during the pump cavity fill stroke of the pump. Any suitable configuration of anti-stall grooves 113 may be provided, including an array of intersecting grooves as shown in one embodiment. In testing, it was discovered that if smooth surfaces are provided within the pumping cavity 112, the flexible diaphragm tends on occasion to get stuck on the concave curved surface. This unfortunately blocks fluid flow and pumping before the diaphragm is fully displaced/deformed and prevents the appropriate liquid volume in the lower chamber from being fully expelled. This causes inconsistency in the volume of fluid pumped per actuation, which can adversely affect proper sample fluid processing and analysis since the volumetric capacity for each pump chamber is carefully predetermined and timing of the discharge of sample fluid to the plasma torch is important.

[0107] It bears noting that the concave shaped pumping cavity 112 defines the volumetric capacity of each diaphragm pump which is dispensed with each pump stroke. When the pumps M1-M4 are actuated, a flow of the pumped process fluid is dispensed based on the volumetric capacity of the pumping cavity. With the hybrid pump, the dispensed volume is infinitely variable up to the maximum volume of the cavity based on the amount of pilot fluid displaced for the pump stroke. [0108] The diaphragm-operated hybrid pumps M1-M4 each include a pilot fluid operating mechanism operable to flow and displace a pilot fluid which actuates the diaphragm 111 for drawing the process fluid into the pump and pumping the fluid out. In one embodiment, a positive displacement pump operable to pump the pilot fluid and actuate the diaphragm may be incorporated directly into the pump body to provide the operating mechanism. This is distinguishable from external pumps or compressed air sources which might be used and add bulk to the apparatus and system. Incorporating the positive displacement pump directly into the pump body is efficient and conserves space.

[0109] In one embodiment, the positive displacement pump may be a syringe pump 115 and the pilot fluid may be a liquid fluid such as oil or water; both of which are generally incompressible relative to air or other gases. Hydraulic oil may be used in one preferred but non-limiting embodiment as the pilot fluid since the elastomeric or rubber material used to make the pump diaphragms is not entirely impermeable to gas including air. Accordingly, if air were to be used as the pilot fluid for actuating the diaphragm valves, some air might pass through the diaphragm from the pilot fluid side and form air bubbles in the process fluid (e.g., slurry, standard solution, diluent, etc.) on the opposite process fluid side of the diaphragm. Due to the viscous nature of oils, it is less likely to penetrate the diaphragms or at least a very minimal amount which would not interfere with the analysis of the slurry via the spectrometer 300. A liquid fluid such as oil is further relatively incompressible which is preferred for the pilot fluid unlike air. However, it bears noting that in some embodiments air could still be used as the pilot fluid although not preferred.

[0110] Each syringe pump 115 may comprise an elongated pump bore 116 formed integrally in the pump body 110. The pump bore contains an inventory or volume of the pilot fluid and is fluidly coupled to the pumping cavity 112 on the inward facing pilot side of diaphragm 111 via a cross flow passage 122a. Syringe pump 115 further includes a pump piston 117 slideably disposed in pump bore 116 and coupled to an operating rod 118 of a linear actuator 119. Actuator 119 may be electric in some embodiments as shown; however other embodiments may use a pneumatic actuator. Any suitable commercially-available linear actuator may be used. In one embodiment, an electric linear actuator 127 having a stepper motor may be used. The stepper motor may be disposed externally on the top or bottom of the pump body 110 and enclosed via a cover 120 coupled to the body by threaded fasteners 121 in one embodiment or other coupling means.

[OHl] Actuator 119 alternatingly is operable to extend or retract the operating rod 118 and piston 117 in pump bore 116. Specially, in one embodiment, the actuator is operable to: move the piston 117 in a first direction to cause the pilot fluid to flow to the pumping cavity 112 of pumps Ml -M4 which deforms and moves the diaphragm 111 towards the process fluid side of the diaphragm to pump process fluid; and move the piston in an opposite second direction to draw the pilot fluid back out of the pumping cavity which moves the diaphragm away from the process fluid side which can draw process fluid into the pumping cavity.

[0112] In one embodiment, the pilot fluid actuation system for the diaphragm pumps M1-M4 may include a pressure relief device 128 comprising a spring-biased piston mechanism also integrated directly into the pump body 110 to conserve space. Relief device 128 includes an elongated relief bore 122 formed directly into the pump body. Relief bore 122 may be parallel to pump bore 116 in some embodiments and each may be cylindrical in shape. The relief bore is fluidly coupled to the pump bore via cross flow passage 122a (see, e.g., FIG. 22) such that over-pressurized pilot fluid may enter the relief bore from the system to prevent damaging the diaphragm of the diaphragm pumps. To provide this protection, a relief piston 123 is slideably disposed in the relief bore and acted upon by a relief spring 124 in the bore. The operating face of the relief piston 123 is acted directly on by the pilot fluid and the opposite side of the piston is acted upon by the spring. A threaded cap 125 may be coupled to the pump body 110 at relief bore 122 to retain the spring in the relief bore. The relief piston and spring assembly act in concert as a fluidic shock absorber to dampen pressure surges in the pilot fluid system. In operation, overpressurization of the pilot fluid moves the relief piston 123 towards and compresses relief spring 124 to absorb the excess pressure. When the overpressurization condition abates, the spring will relax to move the relief piston back to its normal operating position in the relief bore 122.

[0113] In each pump M1-M4, the diaphragms and pumping cavities 112 are preferably vertically oriented especially with respect to the sample pump M4. Some air may make its way into the pumping system which can adversely affect pumping performance and flow. By orienting the pumping cavities and diaphragms vertically, air bubbles will collect at the top of the pumping chamber where the bubbles may be removed during commissioning or service. Any air anywhere in the pilot fluid side decreases total pump displacement and causes compressibility in the system which is highly undesirable. To ensure accuracy of the spectrometry analysis of the sample fluid (e.g., slurry in one embodiment) in the plasma torch device 200 in particular, the sample fluid outlet port 151 of sample pump M4 (which is formed by pump manifold block 134 as described elsewhere herein) is preferably positioned in the middle of the pumping cavity as shown in FIGS. 27-28. This minimizes the chance that any air bubbles accumulating at the top of the pumping cavity might be drawn into the slurry discharge with each pumping stroke rather than remain at the top of the pumping cavity.

[0114] As shown in FIG. 26, the pump bore 116 and relief bore 122 may be vertically oriented and elongated as formed integrally with pump body 110. The cross flow passage 122a may be horizontally oriented, or oriented at an oblique angle to a horizontal reference plane in other embodiments. Bores 116 and 122 may be parallel to each other as shown, or obliquely angled or perpendicular to each other in some embodiments. The pump and relief bores may comprise cylindrical walls which slideably engage the pump and relief pistons 117, 123, respectively. Pump bore 116 is terminated at the end opposite the actuator 119 with a reduced diameter flow exchange bore 116a having a diameter smaller than the pump bore. Similarly, relief bore 122 is terminated at the end opposite the spring 124 end with a reduced diameter flow exchange bore 122b having a diameter smaller than the relief bore. Bore 122b may extend completely through the pump body 110 to define an externally accessible pilot fluid fill port for adding or extracting the pilot fluid. The bore 122b in this case is sealed by a removable plug 126 affixed to the pump body which provides selectable access to the reservoir of pilot fluid in the pump body defined primarily by the pump bore 116, relief bore 122, and cross flow passage 122a for filling or extracting pilot fluid. The bores 116a and 122b define orifices are fluidly connected to the cross flow passage 122a as shown, which in turn is fluidly connected to the pumping cavity 112 associated with the diaphragm 111.

[0115] In one embodiment, the pressure of the pilot fluid may be monitored by the controller 2820 via a pressure sensor 520 operable to measure the pressure of the pilot fluid (see, e.g., FIG. 20). This information can be useful for purposes including identifying if a blockage downstream of pumps M1-M4 occurs in the flow passages occurs and flow diagnostics. Sensor 520 may be operably coupled to any convenient and accessible portion of the pilot fluid reservoir 521 (defined primarily by cross flow passage 122a, pump bore 116, and relief bore 122 which hold a majority of the volume of the pilot fluid) which can provide a pressure measure indicative of the actual pilot fluid pressure. In one example shown, the pressure sensor 520 may be operably coupled to the pilot fluid through plug 126 which seals the pilot fluid fill port defined by reduced diameter flow exchange bore 122b associated with the relief bore 122 described elsewhere herein. Other points of connection including separate discrete path to the pilot fluid may be used to monitor the pilot fluid pressure. Any commercially-available pressure sensor may be used which is configured to be operably and communicably linked to controller 2820 may be used.

[0116] Pumps M1-M4 may be oriented vertically as shown in one embodiment with pump and relief bores 116 and 122 being vertically elongated. In other embodiments, the pumps may be oriented at other positioned including horizontal with bores 116, 122 being horizontally elongated. Angled orientations neither horizontal or very of the pumps may also be used in some embodiments. Not all pumps need to be in the same orientation, but may be in some embodiments as shown.

[0117] Each diaphragm-operated hybrid pump M1-M4 has an associated pump manifold block containing flow passages 102 which form integral parts of the multi-branched flow network 101 with fluid interconnections configured to produce the flow paths shown in FIG. 3. The manifold blocks control the flow of the process fluids entering and pumped out of the hybrid pumps. In one embodiment, four pump manifold blocks may be provided which form integral parts of the pump assemblies including manifold block 131 corresponding to diluent pump Ml, manifold block 132 corresponding to standard pumps M2, manifold block 133 corresponding to mixing pump M3, and manifold block 134 corresponding to sample pump M4. Other embodiments may have more or less diaphragm pumps depending on the different types of process fluids to be used in the sample analysis system. Manifold blocks 131-134 and mixing manifold block 130 (further described herein) may have a rectangular cuboid shape in one embodiment as shown so that a flat-to-flat interface may be formed with the diaphragm pumps for sealing the pumping cavity, as further described herein.

[0118] Portions of the flow passages 102 in each of the manifold blocks 131-134 form at least one fluid inlet port 150 and at least one fluid outlet port 151 which is in fluid communication with pumping cavity 112 of pumps M1-M4 to exchange fluids therewith. Some manifold blocks may have additional fluid ports. To illustrate this aspect, FIGS. 27 and 28 show pump manifold block 134 for the sample pump M4 as an example. Manifold block 134 may comprise three fluid ports defined by flow passages 102 of the manifold block including a sample fluid inlet port 150a, bottom fluid port 152a, and a middle sample fluid outlet port 151a located anywhere between ports 150a and 152a. Each port 150a, 151a, and 152a is in fluid communication with pumping cavity 112 of pump M4. In one embodiment, with respect to a vertically oriented pumping cavity 112 as previously described herein, sample fluid inlet port 150 may be a top port located in a first upper end region of pumping cavity, fluid port 152a may be a bottom port located in a second lower end region of the pumping cavity, and sample fluid outlet port 151a may be located in a central region of the pumping cavity defines as being anywhere between ports 150a and 152a. In one embodiment, sample fluid outlet port 151a may be disposed proximate to the center of the pumping cavity 112 as shown in FIG. 28.

[0119] The fluid ports of each manifold block (including ports 150a-152a of sample pump manifold block 134 shown in FIGS. 27-28) may extend completely through manifold block 134 from side to side, and each port is fluidly coupled to a continuation of these ports comprising corresponding flow passages 102 formed in mixing manifold block 130 (see, e.g., FIG. 29) which are mated to the ports, which is further described below. The continuations of ports 150a- 152a are numbered as flow passages 150b-152b respectively in FIG. 29. The remaining pump manifold blocks 131-133 are similar with respect to formation of fluid inlet and outlet ports defined by flow passages 102 in each block for their respective pumps Ml -M3.

[0120] Referring back to FIGS. 27-28, sample fluid inlet port 150a is used for adding the agricultural sample slurry into pumping cavity 112 of sample pump M4. The bottom fluid port 152a of sample pump M4 may be used for multiple purposes as shown by the system flow schematic diagram of FIG. 3. One use of port 152a after processing of the agricultural slurry for analysis is to introduce flushing water from a water source as shown in the flow schematic diagram of FIG. 3 (via opening valve VI 2) into pumping cavity 112 of the sample pump to clean out residual slurry from the cavity between sample runs to avoid contaminating the next batch of slurry to be processed. Since different batches of agricultural sample slurry may come from different regions of the agricultural field and exhibit different concentrations/levels of plant available nutrient, it is important to avoid cross contamination to get a true picture of the nutrient levels in each region to plan for soil amendments. By changing position of the valving shown in FIG. 3, the bottom fluid port of sample pump M4 may be used to discard the flushing water to waste via opening valve V8.

[0121] In another second use, bottom fluid port 152a may also be used to add extractant from an extractant source to the slurry in pumping cavity 112 of sample pump M4 for mixing with the sample slurry to draw out a particular analyte of interest (i.e. plant available nutrient). Sample fluid outlet port 151a is used for discharging the mixture of sample slurry and extractant after combined to the plasma torch device 200 for analysis via spectrometer 300 after a plasma is ignited.

[0122] Actuation of the diaphragms 111 of each pump M1-M4 via pilot fluid syringe pumps 115 deforms the diaphragm to pump the process fluid out of pumping cavity 112 via moving the diaphragm towards the process fluid side of the pumping cavity, or to allow the cavity to be filled with process fluid via moving the diaphragm back towards the pilot fluid side of the pumping cavity. In operation of the pumps, in general, the diaphragms are deformable via actuating the syringe pumps 115 which moves pump piston 117 in opposing directions to either push pilot fluid against that diaphragm to pump process fluid, draw pilot fluid back into pump bore 116 to fill the pumping cavities of the hybrid pumps. With respect to the sample pump M4, as an example, the diaphragm is deformable for flowing the agricultural sample fluid into the pumping cavity 112 through sample fluid inlet port 150a, or for pumping the sample fluid out of the pumping cavity through sample fluid outlet port 151a.

[0123] At least some of these manifold blocks 130-133 may also include one or more air-actuated diaphragm valves integrated directly into the blocks and designated VI through VI 0 inclusive. The term “integrated” here refers to the fact that the manifold block bodies form the valve seats, as further described herein. The diaphragm valves variously control the flow of different fluids through manifold the blocks to and from the pumps M1-M4 and to the plasma torch 201 (see, e.g., FIG. 3).

[0124] Sample pump manifold block 134 may not contain any directly integrated diaphragm valves in some embodiments as shown. Manifold block 134 however may include a pair of two- port electric solenoid valves comprising top water valve VI 1 and bottom water valve VI 2 shown in FIGS. 3 and 27. These valves are physically coupled externally to the manifold block and control the flow of water to both sample pump M4 and mixing pump M3 through the flow network shown. Water valves VI 1 and VI 2 are fluidly coupled to a source of pressurized preferably filtered water and normally closed to ensure positive shutoff of water into the flow network 101 system when not desired. This positive shutoff may not be possible with the diaphragm valves which open/close via operation of pressure applied to the diaphragms by fluid flows generated from the pumps Ml- M4. Any suitable commercially-available electric solenoid valves such as those available from SMC Corporation of America or other suppliers may be used.

[0125] FIG. 4 shows the association and layout of the onboard diaphragm valves with their respective manifold blocks 131, 132, 133. The function of valves VI -10 are shown in FIGS. 3 and 4. Specifically, the diaphragm valves include: VI (diluent inlet valve) and V2 (diluent mix valve) associated with manifold block 131; V3 (standard inlet valve) and V4 (standard mix valve) associated with manifold block 132; V5 (sample inlet valve), V6 (sample outlet valve), V7 (extractant inlet valve) and V8 (waste outlet valve) associated with mixing manifold block 130; and V9 (mixing water valve) and VI 0 (transfer valve) associated with manifold block 133.

[0126] The resiliently deformable diaphragm 144 of each valve may be seated in a recessed valve seat 135 formed on one or more external surface of pump manifold blocks 131, 132, and 133. The valve diaphragms 134 and corresponding valve seats 135 may be circular in shape in one embodiment. One or more operating air manifold blocks 138 containing air conduit couplers 138a may be provided which are fluidly coupled to a source 139 of pressurized operating air (see, e.g., FIG. 21). The air manifold blocks 138 may be detachably coupled variously to the mixing and pump manifold blocks 130-134 in one embodiment. The air manifold blocks 138 include internal airways 138b which are configured to fluidly couple the valves VI -VI 0 to the operating air for actuating and moving the valves between open and closed positions. The operating air acts on one side of valve diaphragms 144 and the opposite side is acted on by the process fluid (e.g., sample slurry, standard solution, diluent, water, etc.) whose flow through the flow network 101 is to be controlled by the valves. The valves are changeable between a closed position to block flow through the valve and associated flow passage, and an open position to enable fluid flow.

[0127] FIG. 4 also shows valves V5-V8 which are associated with and incorporated into a mixing manifold block 130 which contains plurality of fluid passages 102 forming part of the flow network 101 seen in FIG. 3. Mixing manifold block 130 further shown in FIG. 29 contains a main flow passage 130a which is in direct fluid communication with plasma torch 201 which extends into the plasma chamber 202 of the plasma torch device 200, as further described herein. The main flow passage 130a is fluidly coupled to pumps M1-M4 and the flow passages 102 as shown in FIG. 3. Specifically, the main flow passage 130a collects and receives flow from diluent pump Ml, standards pump M2, and sample pump M4 and transfers these flow streams to the plasma torch. Since the fluids from some of these pumps may be simultaneously pumped to main flow passage 130a, the main flow passage may have a larger diameter for increased flow capacity in some embodiments than the other flow passages in mixing manifold block 130. Due to its increased flow manifold block 130 may be centrally located on apparatus 100 directly beneath the plasma torch device so that main flow passage 130a may be coupled readily to cathode tube 203 of plasma torch device 200, as further described herein. The mixing manifold block with diaphragm valves V1-V10 described elsewhere herein functions as a flow control device for the system to receive, discharge, and direct various fluid flows into, through, and out of the flow network 101. Combinations of the various valves are opened or closed to create different fluid pathways for different purposes of the system.

[0128] Referring to FIG. 29, an upper portion of main flow passage 130a defines a common mixing zone Z. This common mixing zone is where the flow passages 102 in mixing manifold block 130 that receive fluid flow from the diluent pump Ml and standards pump M2 are fluidly joined to the main flow passage to mix these flows with sample slurry and extractant mixture from sample pump M4. Preferably, mixing zone Z is located no more than 3 inches from the plasma electrode gap 209 between anode pin 205 and cathode tube 203 (see, e.g., FIG. 38). This is an important consideration since larger than normal passageways must be used to accommodate solid particulate in the sample slurry, so flow passage line volumes add up which ultimately increases the volume of the sample that must be collected and transported to the system. A short length of central passage 130a in the mixing zone Z enables lower line fluid volumes to complete a spectrometry test of the sample slurry.

[0129] Mixing manifold block 130 in one embodiment may be directly interfaced and abuttingly engaged with pump manifold blocks 131, 132, and 134 to form sealed flow passages therebetween at the interfaces. Accordingly, flow passages 102 in these pump manifold blocks fluidly couple to corresponding flow passages in mixing manifold block 103 which serve as continuations of the pump manifold block flow passages to create the flow network 101 shown in FIG. 3. The interface between flow passages in the mixing manifold block 130 and pump manifold blocks 131, 132, and 134 may include an annular seal 137a such as an O-ring seated in a corresponding circular seal recess 137b to form a fluid tight coupling therebetween (see, e.g., FIGS. 22 and 29). When the manifold blocks are abuttingly engaged and coupled together, the seals 137a are compressed and expand to form fluid-tight liquid interconnections between the blocks.

[0130] The pump manifold blocks 131-134 together with pump bodies 110 form a complete and fluidly sealed pump assembly for pumps M1-M4. Accordingly, each pump manifold block has a flat active outer surface 134a which abuttingly engages and interfaces with the active outer surface 107a of their associated pump body to enclose and seal the respective concave pumping cavity 112 with the diaphragm 111 being trapped therebetween. To illustrate this point as one representative example, FIGS. 27-28 show the pump manifold block 134 associated with the pump assembly of sample pump M4. Active outer surface 134a of manifold block 134 abuttingly engages the active outer surface 107a of the sample pump body 110 (see, e.g., FIGS. 22 and 25-26). The active outer surface of the manifold block 134 comprises a pumping recess 136 which has a perimetric shape in outline that is complementary configured (e.g., shape and dimension) to the pumping cavity 112 of the pump body for the sample pump. In the illustrated embodiment, pumping recess has a circular perimetric shape. In contrast to the concave pumping cavity 112 of the pump body 110 which has a bottom wall with an arcuately curved shape (see, e.g., FIGS. 22 and 26), the bottom wall of the pumping recess 136 may have a flat profile. The pumping recess 136 and pumping cavity 112 are arranged in opposing facing relationship to form a complete operational pumping chamber collectively formed by the pump body in part and associated pump manifold block in part. The manifold block thus encloses the pumping cavity. This same arrangement and pumping recess are similar for the manifold blocks associated with the remaining pumps Ml , M2, and M3 without undue explanation necessary of each for sake of brevity.

[0131] In some embodiments, the pumping recesses 136 of the pump manifold blocks 131-134 may also include anti-stall grooves 113 similar to the pumping cavities 112 of the pumps hybrid M1-M4. These anti-stall grooves in the manifold block are recessed into the flat bottom wall of the pumping recesses 136 to prevent the diaphragm from adhering to and getting stuck on the surface when the diaphragm 111 is actuated and deformed during the outward fluid pumping stroke toward the manifold blocks. Any suitable arrangement of anti-stall grooves may be provided as needed to prevent diaphragm sticking.

[0132] The block-shaped pump bodies 110 of pumps M1-M4, mixing manifold block 130, and pump manifold blocks 131-134 are polygonal shapes which may be tightly abutted and detachably coupled together to collectively form a compact apparatus housing 100a having a configuration as shown. Threaded fasteners 140 may be used in one embodiment (see, e.g., FIG. 22) to couple these components together in the arrangement shown in the figures. Threaded fasteners may also be used in a similar manner to detachably couple each pump manifold block to their respective pump. The pump bodies and manifold blocks may include fastener mounting openings as shown for example in FIG. 29 which threadably engage fasteners 140. Other mechanical coupling means may also be used instead of or in addition to threaded fasteners in other embodiments. The housing 110a has sufficient structural rigidity to support the plasma torch device 200 and spectrometer 300 which are attached to the block-shaped components by suitable means such as threaded fasteners. The housing is a structurally self-supporting unit when the block-shaped flow-related components are assembled and is portable and readily transportable. It bears noting that the fluid side components, plasma generation components, and spectrometer components are cooperatively packaged together thereby forming a complete agricultural sample fluid analysis system.

[0133] According to one aspect of the invention, the mixing pump M3 and sample pump M4 are fluidly coupled together according to FIG. 3 and operable to function as a mixer for combining extractant and additional water if needed with the agricultural sample fluid which may be a slurry in some embodiments. Physically, mixing pump M3 with manifold 133 may be vertically stacked on top of sample pump M4 with manifold 134 to facilitate the mixing the fluids/chemicals. As mentioned elsewhere herein, sample pump manifold 134 includes three ports: sample fluid inlet port 150a, sample fluid outlet port 151a, and bottom fluid port 152a. Mixing pump M3 is fluidly coupled to sample pump M4 via transfer valve VI 0. In operation, the sample slurry is added into sample pump M4 via sample fluid inlet valve V5. An amount of the appropriate extractant formulated to draw the analyte of interest out of the slurry is added to the slurry in the sample pump. An additional amount of water if needed may be added to the mixture in sample pump M4 via electric water valve V12 to dilute the slurry to the desired water to sample solids ratio (e.g., soil/water ratio in one embodiment). Preferably, each constituent of the slurry mixture (i.e. slurry, extractant, and water) is added to pumping cavity 112 of sample pump M4 one at a time so that a precise metered amount of each fluid can be incorporated thereby allowing control over the composition of the mixture. Once the mixture is complete, mixing pump M3 and sample pump M4 may be operated in an alternating manner to shuffle the slurry mixture back and forth between the pumps to ensure thorough mixing. As an example, with transfer valve VI 0 open shown in FIG. 3, sample pump M4 discharges the slurry mixture into mixing pump M3. Then, mixing pump M3 returns the slurry mixture to sample pump M4. This process may be performed for one or more cycles as need until the slurry mixture is completely mixed. No physical stirring of the slurry mixture occurs. After mixing is complete, sample pump M4 may discharge the slurry mixture via sample fluid outlet port 15 la to mixing manifold block 130 and the main flow passage 130a therein to the plasma torch 201.

[0134] The plasma torch device 200 and spectrometer 300 of the agricultural sample fluid analysis system will now be further described. The plasma torch device 200 is an apparatus which is electrically energizable to prepare the agricultural sample for spectroscopic examination by vaporing a flow of an agricultural sample fluid such as slurry or other liquid to create a plasma. Accordingly, plasma torch device 200 comprises both fluidic portions in fluid communication with pump M4 to receive the sample fluid, and electrical portions operable to ignite and vaporize the sample fluid to generate a plasma for analysis by spectrometer 300.

[0135] FIGS. 30-38 show the plasma torch device in isolation and greater detail. Referring initially to these figures, plasma torch device 200 generally comprises a body 210 which may have a rectangular cuboid shape in one embodiment including a top 211, bottom 212, and four adjoining sides 213. Other configurations of housing may be used and does not limit the invention. Body 210 has a configuration which defines an open plasma chamber 202. Body 210 may be detachably coupled to and supported by one or more of the diaphragm pumps M1-M4 and/or the manifold blocks 130-134. Threaded fasteners such as those described herein may be used. Body 210 may be generally rectangular cuboid in shape and may comprise a monolithic body formed of a suitable material such as metal or a plastic, or a combination of these or other materials.

[0136] The plasma torch device body 210 supports plasma torch 201 which has portions exposed in the plasma chamber for creating the plasma is created from the agricultural sample fluid for analysis. The housing also supports a pair of electrodes; one electrode 208 is electrically coupled to a suitable electric power source PS which may be a DC power supply in one embodiment, and the other electrode 207 is electricity coupled to ground G (represented schematically in FIG. 36).

[0137] The plasma torch 201 includes an anode pin 205 electrically coupled to the positive electrode 208 and a cathode tube 203 electrically coupled to the ground electrode 207. Anode pin 205 may have a solid structure and is supported by a pin holder 206 coupled to the plasma torch device body 210 (see, e.g., FIGS. 37-38). Pin holder 206 defines a passage 206a which receives the anode pin 205 at least partially therein. The pin holder is electrically coupled to power electrode 208, which in turn energizes the anode pin. Cathode tube 203 is supported by a tube holder 204 defining a passage 204a which receives the cathode tube at least partially therein. The polarity of the anode and cathode could potentially be reversed and multiple options are possible such as for example without limitation: (1) Positive +5 kV electrode (anode) at the top, grounded (0 kV) solution (cathode) at the bottom; (2) Positive +5 kV solution on the bottom, grounded electrode at the top; (3) Negative -5 kV electrode at the top, grounded (0 kV) solution at the bottom, or (4) AC power supply going to anode (±5 kV) , grounded solution (0 kV). The tube holder is electrically coupled to ground electrode 207, which in turn electrically grounds the cathode tube. The anode pin and cathode tube may each have a generally cylindrical shape in one embodiment and are formed of an electrically conductive metal. Other shapes and exterior profiles are possible.

[0138] One end of each of the anode pin 205 and cathode tube 203 project into plasma chamber

202 for a distance. The tips of the anode pin and cathode tube in the chamber are spaced apart by a gap 209 where the plasma is generated by igniting a flow of the agricultural sample fluid such as a sample slurry in some embodiments. To deliver the slurry to the plasma chamber, cathode tube

203 includes a longitudinal fluid passageway 203a which extends completely through the tube from the flow discharge tip in the plasma chamber to the opposite flow entrance end which may be positioned inside passage 204a of the cathode tube holder 204 (see, e.g., FIGS. 37-38). Cathode tube 203 is fluidly coupled (in fluid communication) to all of the process fluids as shown in FIG. 3 including with sample pump M4 for receiving the sample slurry via main flow passage 130a of mixing manifold block 130 (see, e.g., FIG. 29). In one embodiment, the cathode may be configured to inject a conductive fluid into the longitudinal fluid passageway thereof and mix the conductive fluid with the sample fluid upstream of the gap. Example conductive fluids include nitric acid and hydrochloric acid.

[0139] Plasma torch device body 210 further includes a waste sink 215 positioned in plasma chamber 202 and formed integrally with the body in one embodiment. Housing may be generally rectangular cuboid in shape and may comprise a monolithic body formed of a suitable material such as metal or a plastic. Other shaped bodies such as round (cylindrical) as one non-limiting example may be used. The sink comprises a depression formed in the bottom wall of the plasma chamber which collects excess process fluid such as the agricultural sample fluid (e.g., sample slurry), standard solution, diluent, or flushing water expelled from cathode tube 203. Sink 215 extends partially in a front to rear direction from front 216 of body 210 towards the rear 217, and partially in a side-to-side direction in the area below the cathode tube. The waste sink may be concave and arcuately curved from side-to side so that the waste fluid accumulates in the central portion of the sink. A waste trough 214 is formed in the bottom wall of the sink to collect waste fluid and direct the fluid outwards through exit opening 214a of the trough to waste. Exit opening 214a penetrates one side of the plasma torch device housing in one embodiment. A waste fluid connector 214b may be provided which is configured to be fluidly coupled to a waste conduit (e.g., piping or tubing) not shown for conveying the excess waste process fluid to waste.

[0140] Plasma torch device 210 is operably interfaced with and coupled to spectrometer 300 which has a direction or indirect line of sight into the plasma chamber 202 for capturing light emitted by the plasma for analysis to measure analytes of agricultural interest in the sample slurry. A nonlimiting example of an indirect line of sight is using an optics cable or light bending lens configuration to capture and direct the light emitted by the plasma to the spectrometer. A nonlimiting example of a direct line of sight to the spectrometer from the plasma chamber which is illustrated in the figures is using a linear light collection tube. For this example, body 210 of the plasma torch device includes a rear through passage 220 formed through a rear wall of the body and configured to accept the light collection tube 301 of the spectrometer which gives the spectrometer a direct line of sight into the plasma chamber 202. In one embodiment, light collection tube 202 may include an objective lens 302 which forms a physical barrier that prevents vapors or mist created by igniting a plasma in plasma chamber 202 from reaching and wetting the operating parts of the spectrometer like the photodetector and electronics. Lens 302 may be made of a suitable material such as sapphire or quartz in some embodiments. Lens 302 may preferably be located 1-4 inches from the centerline CL of the plasma torch 201 defined by the anode and cathode (see, e.g., FIG. 37), which may each be vertically oriented in one embodiment as shown. Because light intensity captured by the spectrometer falls off as a function of distance, it is therefore preferable to locate the spectrometer as close as possible to the plasma within this preferred range of distance for a strong light signal but not too close to reduce fouling/fogging of the lens as described below. Through passage 220 may extend horizontally through the rear wall 217a of the body 210 in one embodiment as shown best in FIG. 38.

[0141] The lens 302 may be subject to fogging when the wet agricultural sample slurry mixture is ignited in the plasma chamber 202 and vaporized. This fogging may adversely affect the accuracy of measurements performed by the spectrometer. To help combat this problem, the lens 302 is recessed in the through passage 220 and separated from the plasma chamber 202 by a distance selected to minimize vaporized slurry from depositing on and fogging the surface of the lens. In other embodiments where this may not be sufficient, an automatic lens cleaning system may be provided to clean and defog the lens.

[0142] In one embodiment, the lens cleaning system may include blowing an air stream across the outer surface of the lens 302 facing the plasma chamber 202. The rear wall 217a of plasma torch body 210 includes an air inlet passage 221 fluidly coupled to a pressurized air source 223 (shown schematically in FIG. 38). The air may be heated in some embodiments above ambient temperature to increase the dew point of the airstream and both prevent condensation and dry any moisture that might have already condensed on the lens. Passage 221 is fluidly coupled to through passage 220 and configured to direct a flow of air across the spectrometer lens 302. The air is captured by an air outlet passage 222 in the housing rear wall 217a which is in fluid communication with lower ambient atmospheric pressure. In one embodiment, the air may travel tangentially over the exposed lens surface to minimize possible escape of some air into the plasma chamber 202 through the through passage 220 which might disturb the plasma.

[0143] To further prevent the defogging airflow from disturbing and destabilizing the plasma generated in plasma chamber 202, the plasma chamber may be physically sealed from the spectrometer lens 302 and the airflow by providing a light-transmissible barrier 220 ’(represented schematically by dashed lines in FIG. 38).

[0144] Other means for defogging the spectrometer lens 302 may be used, including without limitation electrically heating the lens with a heater, continuously applying a flow of a cleaning solution across the surface of the lens, physically wiping the lens with a mechanical wiping device including a wiping element that contacts and moves across the surface of the lens, or others.

[0145] Spectrometer 300 may be any commercially-available spectrometer suitable for use with atmospheric pressure glow discharge flowing liquid cathode atomic emission spectrometry which is implemented by the present agricultural sample analysis apparatus 100. Such an examination technique is well known in the art.

[0146] A method or process for operating the agricultural sample analysis apparatus 100 for processing and analyzing an agricultural sample fluid will now be briefly described. The process described below and other aspects of processing and analyzing the sample fluid may be automatically controlled and implemented by programmable controller 2820 further described herein.

[0147] In operation, the diaphragm-operated hybrid pumps Ml, M2, and M4 may initially be filled with their respective process fluids including diluent, standards solution, and agricultural sample fluid respectively via opening/closing the appropriate valving shown in FIG. 3. The sample fluid may be a slurry containing solids or filtrate produced from filtering an agricultural solids slurry (e.g., soil, crop residue, manure, etc.) outside the apparatus 100 which is then added to the sample pump M4. The sample fluid may be further prepared for processing and analysis by adding extractant and additional water if required to sample pump M4 via extractant inlet valve V7 and water valves VI 1 or VI 2. The mixture may be mixed in via exchanging the mixture with mixing pump M3 one or more cycles as previously described herein to ensure thorough mixing and a homogenous sample fluid is produced for generating the plasma.

[0148] Once the diluent pump Ml, standards pump M2, and sample pump M4 are primed with their respective process fluids, the system is ready to begin pumping the agricultural sample fluid (i.e. mixture of sample fluid, extractant and additional water if added) to the plasma torch device 200 to generate the plasma. Reference is made to FIG. 1 which shows the basic process. Diluent, standards solution, and agricultural sample fluid may first be pumped and conveyed to plasma torch 201 of the plasma torch device 200 via mixing manifold block 130 and main flow passage 130a therein (previously described herein) before igniting the plasma. This provides a “washout” period to get rid of any air bubbles which might be entrained in the process fluids before the plasma is lit. These three process fluids may be pumped and discharged to the plasma torch in a preselected proportional rate, which may be programmed into controller 2820 which controls the process sequence and analysis implemented by sample analysis apparatus 100. Accordingly, the process includes varying individual flowrates from each of the hybrid pumps Ml, M2, and M4 to achieve a specific ratio of each process fluid in the combined flow to the plasma torch.

[0149] As a non-limiting example of the above proportional flow scheme, a ratio of 20% sample fluid, 20% standards solution, and 60% diluent could be used in some embodiments. Other proportional flow combinations may be used as appropriate for different analytes. The three process fluids are mixed in mixing zone Z of the mixing manifold block and then flow to cathode tube 203 from which the fluids are dispensed into gap G between the cathode and anode (see also FIGS. 36-38). Flow may be initiated to the plasma torch before the plasma is ignited to provide time to equilibrate the flow stream first. The combined process fluid stream may be conveyed to the plasma torch 201 at an appropriate preselected fixed flowrate (e.g., milliliters per minute) which can be selected at least in part to establish a stable plasma.

[0150] According to one aspect of igniting a plasma from the sample fluid, standards solution, and/or diluent, the inventors have discovered that a steady state flow rate of these process fluids desired to measure the analyte in the sample fluid is not necessarily an ideal flow rate for igniting and initially sustaining the plasma. Specifically, it has been discovered that a higher flow rate of these process fluids is advantageous to ignite the plasma.

[0151] Accordingly, a process or method for operating a plasma torch may comprise steps including but not limited to: increasing flow of a process fluid through a hollow electrode of the plasma torch to a first flow rate; igniting a plasma from the process fluid via energizing the hollow electrode; decreasing the flow of the process fluid to a second flow rate lower than the first flow rate; and measuring the process fluid for an analyte of interest at the second flow rate. The first flow rate increases the amount of process fluid dispensed which in turn reduces the effective air gap measured between the fluid and the anode or cathode (one of which is the hollow electrode configured to receive and dispense the process fluid and the other which may be solid). Once the plasma has been ignited and stabilized, the flow rate and effective air gap may be decreased to the steady state flow condition at the second flow rate to collect the analyte measurements. The process fluid may comprise the sample fluid which contains the analyte of agricultural interest and value. This stepped and staged flow rate control is effective for igniting and stabilizing the plasma generated by the energized plasma torch.

[0152] Once flow has been established, the plasma torch 201 is then energized by turning on the power to the plasma torch device, which ignites a plasma between the process fluid stream and the opposing electrode. Controller 2820 may initiate a timer after the plasma is lit for a preprogrammed “wait time.” This ensures that the plasma has been stabilized to avoid inaccurate measurement of the analyte of agricultural interest in the sample fluid. After the timer runs out, the spectrometer 300 captures the light (spectra) emitted by the plasma to measure the analyte. One or more spectra capture events (exposures) may be made by the spectrometer to provide multiple data points which can be averaged to determine a level or concentration of the analyte present in the sample (e.g., plant available nutrient). The measurements are transmitted and communicated to the controller 2820. [0153] Once measurements are completed, the plasma torch 201 is de-energized and pumps Ml, M2, and M4 may be stopped. This ends a first sample processing run.

[0154] Although in the non-limiting example process described above the plasma is generated from three process fluids and the associated spectra measurements are captured by spectrometer 300, in other embodiments the plasma may be generated and spectra measurements taken by flowing the agricultural sample fluid through the plasma torch 201 alone. In yet other variations of the process, a proportional combination of the diluent and sample fluid without the standards solution may be initiated to generate the plasma and capture spectral data before replacing a portion of the diluent with the standards solution. For example, an initial flow stream to the plasma torch may comprise 80% diluent and 20% sample fluid to produce the plasma and capture the spectral data at the start. The standards solution may then be initiated to replace a portion of the diluent until a ratio of 20% sample fluid, 20% standards solution, and 60% diluent is established while the plasma remains lit and spectral date is captured by spectrometer 300. Other ratios of the diluent, standards solution, and sample fluid may be used.

[0155] It bears noting that the foregoing combined flows of process fluids (diluent, standards solution containing a known amount of the analyte to be measured in the sample, and agricultural sample fluid) allows the spectrometer to be dynamically calibrated on the fly during the analysis process. In other embodiments, a typical batch calibration may be used to calibrate the spectrometer in which successive runs of standards solution alone each with a different concentration of the analyte are processed in succession generate the plasma and capture the spectral data. Accordingly, any suitable method of calibrating the spectrometer and analyzing the agricultural sample fluid are possible with the present agricultural sample processing and analysis system.

[0156] The present agricultural sample processing and analysis system by virtue of controller 2820 and the internal flow network 101 embodied in sample analysis apparatus 100 as previous described herein advantageously provides consideration operational flexibility. In addition to creating proportional flowrates and mixing of different process fluids (e.g., diluent, standards solution, and agricultural sample fluid) from hybrid pumps Ml, M2, and M4 as previously described herein, the system can implement ramping down a flowrate of a first process fluid from a first hybrid pump to the plasma torch 201 while simultaneously ramping up a flowrate of a second process fluid discharged from the second hybrid pump to the plasma torch in order to maintain a minimum flowrate to the plasma torch necessary to sustain a stable plasma. In addition, a first hybrid pump may be filled with a first process fluid while simultaneously discharging a second process fluid to the plasma torch from a second hybrid pump. The operation of the first and second hybrid pumps may be toggled back and forth such that a continuous supply of either the first or second process fluid is maintained to the plasma torch to sustain a stable plasma. The preceding are some non-limiting examples of the operational flexibility of the system. Other variations are possible due to the flow network 101 of the system including the hybrid pumps and valving shown in FIG. 3.

[0157] The agricultural sample processing and analysis system further includes provisions for flushing and cleaning out the hybrid mixing pump M3, hybrid sample pump M4, and plasma torch 200 with water as shown in FIG. 3 by opening and closing the appropriate valving associated with the water supply and pumps. The waste water is discarded via waste outlet valve V8. The water cleaning system may be used between each sample fluid run through the system to prevent crosscontamination of samples.

[0158] When made of plastic, transparent polymeric materials may be used in one embodiment to form the monolithic manifold blocks 130-134 and hybrid pump bodies 110 to allow visual observation of the fluids being processed therein and operation of the pumps and diaphragm valves. Some non-limiting examples of thermoplastics (polymers) which may be used include for example without limitation PMMA (polymethyl methacrylate commonly known as acrylic), PC (polycarbonate), PS (polystyrene), PVC (polyvinyl chloride), CPVC (chlorinated polyvinyl chloride), and others. Examples of suitable elastomeric materials which may used to form the diaphragms of the hybrid pumps and valves V1-V10 include without limitation silicone, PDMS (polydimethylsiloxane), fluorosilicone, neoprene, and others. The pressurized air used to hold the diaphragm valves closed will permeate through elastomeric diaphragms over time, causing air bubbles to develop in the process fluid side of the valves. These air bubbles negatively affect the ability to volumize liquids properly, as the air bubbles displace the otherwise precise fluid volumes that are being manipulated. Fluorosilicone is one preferred non-limiting material due its low gas permeability property which aids in decreasing gas diffusion through the diaphragm over time to combat the foregoing problem.

[0159] Pressure-Balanced Seal System for Positive Displacement Pumps [0160] FIGS. 39 and 40 show an alternative embodiment of the hybrid pumps M1-M4 in which the syringe pumps 115 which control the pilot fluid to operating the pumps M1-M4 further comprises a pressure-balanced seal system.

[0161] Dynamic seals such as those formed by pump piston 117 slideably moving back and forth within pump bore 116 of syringe pump 115 when the hybrid pumps are actuated are very difficult to seal when a vacuum condition occurs in the pilot fluid (e.g., oil in one embodiment). This vacuum condition occurs during the return or reverse stroke when the syringe pump retracts in the pump bore 116 to pull back on the pilot fluid in pumping cavity 112 in order to draw the diaphragm 111 of the hybrid pump inwards against the curved surface of the concave pumping cavity (see also FIGS. 19-22 and 25-26). This makes it possible to pull air both past and through (via permeation) the seals on the pump piston 117. Once air infiltrates into the pilot fluid system, it displaces oil and changes the total volume of the pilot fluid system thereby adversely affecting proper operation of the system. In order to combat this, a pressure-balanced piston device 400 such as shown in FIGS. 39-40 can be used according to the present disclosure.

[0162] The pressure-balanced piston 400 replaces single pump piston 117 with a dual piston assembly 400s comprising a primary operating piston 401 and a secondary sealing piston 402 connected together by a diametrically smaller intermediate connecting member 403. Sealing piston 402 is coupled to operating rod 118 of linear actuator 127 for moving the piston assembly back and forth in pump bore 116 as previously described herein. The piston assembly may have a monolithic body in which the pair of pistons and connecting member are all formed as integral unitary parts of the body. The connecting member may therefore be a reduced diameter middle portion of the body. In other embodiments, connecting member 403 may be a separate component coupled to and between pistons 401, 402. Each piston 401, 402 comprises one or more annular seals 403 such as elastomeric O-rings to seal the sliding interface between the cylindrical piston sidewalls and the cylindrical inside surface or walls of the pump bore 116.

[0163] A pressure balancing intermediate chamber 404 is formed in pump assembly between the pistons 401, 402 due to the smaller diameter of connecting member 403 than the pistons and pump bore 116 as shown. The intermediate chamber 404, of annular shape therefore, contains a reservoir or volume of the pilot fluid (e.g., oil or other) filled on a pilot side of operating piston 401 opposite the working side of the piston which operably displaces the pilot fluid in cross flow passage 122a to actuate the hybrid pump diaphragm 111 when the syringe pump 115 is actuated. A reservoir or volume of the pilot fluid is also contained in cross flow passage 122a and pump bore 116 on the working side of operating piston 401 the same as previously described herein. Oil may be used in one embodiment as the pilot fluid.

[0164] The pressure balancing intermediate chamber 404 is fluidly coupled via flow conduit 406 to a pressure control apparatus 410. Apparatus 410 is configured and operable to adjust the pressure in the intermediate chamber during operation of the hybrid pumps so that the pressure of the pilot fluid in the chamber is less than the pressure of the pilot fluid on the working side of piston 401. In one embodiment the pilot fluid may be used both in chamber 404 and on the working side of operating piston 401 between the piston and diaphragm 111 of hybrid pumps M1-M4 in the cross flow passage 122a, as previously described herein. This is advantageous in the event of any leakage past the seals on the operating piston 401 between the intermediate chamber 404 and working side of the operating piston. A pilot fluid reservoir 413 may be incorporated in flow conduit 406 and fluidly interposed between pressure control apparatus 410 and intermediate chamber 404 of operating piston assembly 400a. The reservoir holds a volume of pilot fluid subjected to a negative pressure (vacuum) applied by apparatus 410.

[0165] In particular, the pressure control apparatus 410 is configured to control and set the pressure of the pilot fluid in intermediate chamber 404 during the return stroke of the syringe pump 115 when the diaphragms 111 of the hybrid pumps M1-M4 are drawn back into the concave recess of the pumping cavity 112. At this time, a vacuum is created in a first pressure zone on the working side of primary operating piston 401 which is in fluid communication with the pumping cavity 112 via cross flow passage 122a as previously described herein. In one embodiment, the pressure control apparatus 404 may be a commercially-available vacuum pump which may include a user- adjustable vacuum regulator 411 thereby providing a means for allowing the pressure in intermediate chamber 404 to be set. The vacuum pump is fluidly coupled to intermediate chamber 404 of the piston assembly 400a via a fluid penetration in pump bore 116.

[0166] In operation, the pressure control apparatus 410 draws a vacuum on intermediate chamber 404 of the operating piston assembly 400a in pump bore 116 so that the pilot fluid pressure in this pressure zone is lower than the pilot fluid pressure in the pressure zone formed on the working side of the operating piston 401. The pilot fluid pressure in the working side pressure zone preferably remains higher during the return stroke of operating piston 401a than the pilot fluid pressure in the pilot side pressure zone formed by intermediate chamber 404 at all times during the return pump stroke. This ensures that any air leaking into the pumping system will be flow into the lower pressure zone in the intermediate chamber.

[0167] In sum, since positive pressure oil is much easier to seal, it is possible to pull suction on the back side of the primary oil seal (e.g., primary operating piston 401) in the intermediate pressure balancing chamber 404 via pressure control apparatus 410 to lower the pilot fluid pressure therein, thus making the pilot fluid higher in pressure on the operating side of operating piston 401 which acts on the hybrid pump diaphragm 111 than the pilot fluid contained in the intermediate pressure balancing chamber 404 between the pistons 401 and 402. When this occurs, the working side pilot fluid cannot draw air into the fluid. Since the pistons 401, 402 are of the same area and coupled together via connecting member 405, there is no net force on the piston.

[0168] Also, a fluid such as oil when used for the pilot fluid on both sides of primary operating piston 401 can be maintained in the intermediate pressure balancing chamber 404 to keep the primary sealing interface formed by primary operating piston 401 and inside surface of pump bore 116 in a regime where it is sealing oil from oil, instead of air from oil which is much more difficult. [0169] To further mitigate any possible air leakage into the pumping system, the same type piston assembly may be incorporated in the pressure relief system of hybrid pumps M1-M4. Specifically, a relief piston assembly 420 may be slideably disposed in relief bore 122 of pump body 110. Piston assembly 420 includes relief piston 421 coupled to a spaced apart second sealing piston 422 by connecting member 423. Piston assembly 420 may be the same as operating piston assembly 400a previously described herein and contains the same features such as seals 403. A second intermediate chamber 425 is formed between pistons 421 and 422. Relief spring 124 remains the same and acts on the piston assembly.

[0170] In one embodiment, the second intermediate chamber 425 of the relief piston assembly 420 may be fluidly coupled to the first intermediate chamber 404 of the operating piston assembly 400a via pressure equalizing passage 424 formed transversely through pump body 110 between pump bore 116 and relief bore 122. Pump bore 116 and relief bore 122 are therefore in fluid communication, which in turn puts intermediate chambers 404 and 425 in mutual fluid communication. Pressure equalizing passage 424 extends transversely through pump body 110 and is fluidly coupled to pump and relief bores 116, 122 in a middle portion of the bores between the ends of each as shown. Passage 424 is located so that intermediate chambers 404, 425 remains in fluid communication during the full range of axial motion of the pump piston 117 during the pumping and return strokes (see, e.g., FIGS. 39 and 40).

[0171] Intermediate chamber 425 of relief piston assembly 420 defines a third pressure zone. In operation, when the pressure control apparatus 410 (e.g., vacuum pump)draws a vacuum on the pressure zone formed by intermediate chamber 404 of the operating piston assembly 400a, this same vacuum or negative pressure is in turn applied to intermediate 425 in relief bore 122 via the pressure equalizing passage 424. The pressure (negative pressure or vacuum) is therefore equal in both intermediate chambers 404, 425. Provision of pressure equalizing passage 424 therefore advantageously allows a single vacuum pump to be provided which acts as a common pressure control apparatus which controls the pressure in both intermediate chambers simultaneously, thereby avoiding the cost of providing a second vacuum pump for the pressure relief system.

[0172] FIG. 39 shows the operating piston assembly 400a at the finish of the pumping stroke and start of the return stroke of the syringe pump 115. FIG. 40 shows the operating piston assembly after the full return stroke fully retracted deeper into pump bore 116 via operation of the linear actuator 119. It bears noting at the start and end of the return pump stroke, intermediate chambers 404 and 425 remain in fluid communication via proper positioning of pressure equalizing passage 424 in the pump body 110.

[0173] Pilot Fluid Air Removal System

[0174] According to another aspect of the invention, an air removal system 500 is provided which is configured to actively remove air which might infiltrate into and become entrained in the pilot fluid resulting in the potential process fluid pumping issues and inaccuracies previously described herein. Air removal system 500 is a vacuum-operated system in one embodiment as further described herein. FIGS. 41 to 49 show one possible but non-limiting embodiment of the air removal system. Hybrid pump Ml is shown as a non-limiting example for application of the air removal device.

[0175] Air removal system includes an air removal device 502 fluidly coupled to the internal reservoir (volume) of pilot fluid in the hybrid pump body 110, which is collectively defined primarily by the pump bore 116, relief bore 122, and cross flow passage 122a. Air removal device 502 includes device housing 501 mechanically coupleable to a fluidic component body such as hybrid pump body 110. Housing 501 may be generally cylindrical in shape in one embodiment as shown; however, other configurations for the housing may be used including without limitation cuboid, hexagonal, octagonal, etc. The invention is not limited by the housing shape selected.

[0176] Housing 501 comprises an internal membrane receptacle 503 in which an air permeable membrane 504 is disposed. The receptacle 503 is fluidly coupled to the reservoir of pilot fluid inside pump body 110 by an air inlet 508 on one side of the membrane. Receptacle 503 is fluidly coupled to vacuum source 510 on an opposite side of the membrane by an air outlet 509. The vacuum source a negative pressure on the membrane to draw entrained air out of the pilot fluid through air inlet 509 and the membrane if present in the fluid. In one embodiment, air inlet 508 is an internal fluid passage defined by the housing which may include a stem 508a protruding outwards from housing 501 as shown for coupling the air removal device to the pump body 101. The stem may be at least partially insertable into an opening of a flow passage in the pump body 110 which contains the pilot fluid such as the pilot fluid fill port defined by the reduced diameter flow exchange bore 122b associated with the relief bore 122 previously described herein. Air inlet 508 therefore has a portion extending through the housing 501 and a contiguous portion in the stem (see, e.g., FIG. 49). The pilot fluid fills air inlet up to the membrane 504 and is in wetted contact with the membrane. The pilot fluid side of the membrane is the wet side and the opposite side of the membrane exposed to vacuum is the dry side.

[0177] Besides the pilot fluid fill port, housing 501 of air removal device 502 may also be fluidly coupled to the pump body 510 at any other suitable available port in fluid communication with the pilot fluid, or via a dedicated separate discrete port formed through the pump body 510 which is in fluid communication with the pilot fluid. Because of the clustered hybrid pump arrangement, coupling of the air removal device 502 directly to the pilot fluid fill port might not be possible for each hybrid pump M1-M4.

[0178] In other embodiments, the housing 501 of air removal device 502 may be coupled to other portions of the pump body 510, or may not be physically attached to the pump body at all if sufficient space and clearance prevents direct coupling. In this latter situation, the air removal device may only be fluidly coupled to the pilot fluid through a suitable port of the pump body such as the pilot fluid fill port (i.e. flow exchange bore 122b) noted above or a separate discrete port formed through the pump body 510 which is in fluid communication with the pilot fluid.

[0179] Air outlet 509 extends internally through housing 501. A fluid fitting 512 may be detachably coupled to the housing at the air outlet for coupling to an external flow conduit 510a coupled to vacuum source 510, which may be a vacuum pump in one embodiment. Flow conduit 510a may be piping or tubing in some embodiments. Any shape or type of fluid fitting 512 may be used.

[0180] The membrane receptacle 503 in one embodiment includes a wall 509a on the vacuum side of membrane 504 and an opposing facing second wall 509b on the pilot fluid side of the membrane. The walls may be formed at the bottom of mating recesses in the housing 501 as shown. Walls 509a, 509b each include a plurality of matched airflow through openings 511a, 511b which are in fluid communication with the pilot fluid on one side of membrane 504 and negative pressure (i.e. vacuum) created by the vacuum source 510 on the other side. In one embodiment, the through openings may be comprises of curved slots to maximize the amount of air which can be extracted from the pilot fluid. However, any suitable shapes openings or combination of shapes may be used. In one embodiment, each through opening 511a however preferably has an opposing mating through opening 511b on the other side of membrane 504 so that pairs of openings on each side of the membrane are axially aligned with each other. This creates a contiguous airflow path through the membrane with minimal pressure drop to optimize the amount of air extracted from the pilot fluid.

[0181] In one embodiment, housing 501 may be formed by and comprises a first half-section 501a detachably coupled to a mating second half-section 501b. The membrane receptacle 503 is collectively defined by a receptacle half-portion 503a in half-section 501a and receptacle halfportion 503b in half-section 501b as best shown in FIGS. 44-45 and 49. Membrane 504 is therefore trapped between the half-sections of the housing in receptacle 503 when coupled together.

[0182] The housing half-sections 501a, 501b may be detachably coupled by any suitable mechanical coupling means. In one embodiment, a plurality of threaded fasteners 505 (e.g., bolts or screws) may be used. The fasteners are inserted through fastener openings 506 in half-section 501a and threadably engage mating threaded sockets 507 formed in mating half-section 501b. In other embodiments, sockets 507 may instead be through holes and nuts may be threaded onto exposed bottom threaded shanks of the fasteners which project beyond the through holes to secure the half-sections together. Other types of fastener arrangements, and other types of fastening techniques may be used.

[0183] Air permeable membrane is formed of a material and constructed to create a gas- transmissible interface (air being a gas) between the pilot fluid and vacuum sides of the membrane which does not allow liquid as the pilot fluid to pass therethrough. The therefore allows air entrained in the liquid to be extracted through the membrane via the vacuum/negative pressure while retaining the liquid pilot fluid on the pilot fluid side of the membrane. In one embodiment, the membrane may be formed of silicone rubber; however, other materials may be used.

[0184] As already noted herein, the agricultural sample processing and analysis system and related processes/methods disclosed herein may be used for processing and testing various agricultural materials and substances such as without limitation soil, vegetation/plants, manure, feed, milk, or other agricultural materials for related parameters and analytes of agricultural interest. Particularly, embodiments of the system disclosed herein can be used to test for a multitude of chemical-related parameters and analytes of interest (e.g. plant available nutrients/chemicals) in other areas beyond soil and plant/vegetation sampling, such as those described above with respect to methods for calibration disclosed herein.

[0185] Control System

[0186] The process described herein and performed by the equipment of the agricultural sample processing and analysis system shown in the accompanying figures may be automatically controlled and executed by the programmable system controller 2820. The controller may be part of a main control system such as that further described herein and shown in FIG. 2. The controller 2820 is operably coupled to the components of the chemical analysis sub-system 3003 disclosed herein (e.g., pumps, valves, plasma torch device, spectrometer, etc.) for controlling the process sequence and flow of fluids (e.g., water, air, slurry, extractant, standard solution, etc.) through the system to fully process and analyze the soil or other type agricultural sample.

[0187] FIG. 2 is a schematic system diagram showing the control or processing system 2800 including programmable processor-based central processing unit (CPU) or system controller 2820 as referenced to herein. Controller 2820 may be operably and communicably coupled to all of the functioning flow control related components shown in FIG. 3 (e.g., pumps, valving, etc.), plasma torch device 200, and spectrometer 300. The controller may control operation, sequence, and timing of the various processes described herein including the processing and analysis of the agricultural sample fluid.

[0188] System controller 2820 may include one or more processors, non-transitory tangible computer readable medium, programmable input/output peripherals, and all other necessary electronic appurtenances normally associated with a fully functional processor-based controller. Control system 2800, including controller 2820, is operably and communicably linked to the different soil sample processing and analysis systems and devices described elsewhere herein via suitable communication links to control operation of those systems and device in a fully integrated and sequenced manner.

[0189] Referring to FIG. 2, the control system 2800 including programmable controller 2820 may be mounted on a stationary support in any location or conversely on a translatable self-propelled or pulled machine (e.g., vehicle, tractor, combine harvester, etc.) which may include an agricultural implement (e.g., planter, cultivator, plough, sprayer, spreader, irrigation implement, etc.) in accordance with one embodiment. In one example, the machine performs operations of a tractor or vehicle that is coupled to an implement for agricultural operations. In other embodiments, the controller may be part of a stationary station or facility.

[0190] Control system 2800, whether onboard or off-board a translatable machine, generally includes the controller 2820, non-transitory tangible computer or machine accessible and readable medium such as memory 2805, and a network interface 2815. Computer or machine accessible and readable medium may include any suitable volatile memory and non-volatile memory or devices operably and communicably coupled to the processor(s). Any suitable combination and types of volatile or non-volatile memory may be used including as examples, without limitation, random access memory (RAM) and various types thereof, read-only memory (ROM) and various types thereof, hard disks, solid-state drives, flash memory, or other memory and devices which may be written to and/or read by the processor operably connected to the medium. Both the volatile memory and the non-volatile memory may be used for storing the program instructions or software. In one embodiment, the computer or machine accessible and readable non-transitory medium (e.g., memory 2805) contains executable computer program instructions which when executed by the system controller 2820 cause the system to perform operations or methods of the present disclosure including measuring properties and testing of soil and vegetative samples. While the machine accessible and readable non-transitory medium (e.g., memory 2805) is shown in an exemplary embodiment to be a single medium, the term should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of control logic or instructions. The term “machine accessible and readable non-transitory medium” shall also be taken to include any medium that is capable of storing, encoding or carrying a set of instructions for execution by the machine and that cause the machine to perform any one or more of the methodologies of the present disclosure. The term “machine accessible and readable non-transitory medium” shall accordingly also be taken to include, but not be limited to, solid-state memories, optical and magnetic media, and carrier wave signals.

[0191] Network interface 2815 communicates with the agricultural (e.g. soil or other) sample processing and analysis systems (and their associated devices) described elsewhere (collectively designated 2803 in FIG. 2), and other systems or devices which may include without limitation implement 2840 having its own controllers and devices.

[0192] The programmable controller 2820 may include one or more microprocessors, processors, a system on a chip (integrated circuit), one or more microcontrollers, or combinations thereof. The processing system includes processing logic 2826 for executing software instructions of one or more programs and a communication module or unit 2828 (e.g., transmitter, transceiver) for transmitting and receiving communications from network interface 2815 and/or agricultural sample processing and analysis system 2803 which includes sample preparation sub-system 3002 and the components described herein further including the closed slurry recirculation flow loop 8002 components. The communication unit 2828 may be integrated with the control system 2800 (e.g. controller 2820) or separate from the programmable processing system.

[0193] Programmable processing logic 2826 of the control system 2800 which directs the operation of system controller 2820 including one or more processors may process the communications received from the communication unit 2828 or network interface 2815 including agricultural data (e.g., test data, testing results, GPS data, liquid application data, flow rates, etc.), and soil sample processing and analysis systems 2803 generated data. The memory 2805 of control system 2800 is configured for preprogrammed variable or setpoint/baseline values, storing collected data, and computer instructions or programs for execution (e.g. software 2806) used to control operation of the controller 2820. The memory 2805 can store, for example, software components such as testing software for analysis of soil and vegetation samples for performing operations of the present disclosure, or any other software application or module, images2808 (e.g., captured images of crops), alerts, maps, etc. The system 2800 can also include an audio input/output subsystem (not shown) which may include a microphone and a speaker for, for example, receiving and sending voice commands or for user authentication or authorization (e.g., biometrics). [0194] The system controller 2820 communicates bi-directionally with memory 2805 via communication link 2830, network interface 2815 via communication link 2832, display device 2830 and optionally a second display device 2825 via communication links 2834, 2835, and I/O ports 2829 via communication links 2836. System controller 2820 may further communicate with the soil sample processing and analysis systems 2803 via wired/wireless communication links 5752 either via the network interface 2815 and/or directly as shown.

[0195] Display devices 2825 and 2830 can provide visual user interfaces for a user or operator. The display devices may include display controllers. In one embodiment, the display device 2825 is a portable tablet device or computing device with a touchscreen that displays data (e.g., test results of soil, test results of vegetation, liquid application data, captured images, localized view map layer, high definition field maps of as-applied liquid application data, as-planted or as- harvested data or other agricultural variables or parameters, yield maps, alerts, etc.) and data generated by an agricultural data analysis software application and receives input from the user or operator for an exploded view of a region of a field, monitoring and controlling field operations.

The operations may include configuration of the machine or implement, reporting of data, control of the machine or implement including sensors and controllers, and storage of the data generated.

The display device 2830 may be a display (e.g., display provided by an original equipment manufacturer (OEM)) that displays images and data for a localized view map layer, as-applied liquid application data, as-planted or as-harvested data, yield data, controlling a machine (e.g., planter, tractor, combine, sprayer, etc.), steering the machine, and monitoring the machine or an implement (e.g., planter, combine, sprayer, etc.) that is connected to the machine with sensors and controllers located on the machine or implement.

[0196] The system for analyzing an agricultural sample disclosed herein is usable with and may form part of an overall agricultural sampling and analysis systems, such as but not limited to those described in commonly-owned U.S. Patent Application Publication Nos. 2018/0124992A1,

US20210123836A1, US20210123936A1, US20210131917A1, US20210131929A1,

US20210208035A1, US20210208036A1, US20210208037A1, US20210208123A1,

US20210268456A1, US20210285869A1, US20210341442A1, US20210341452A1,

US20220196628A1, US20230133335A1, US20230144670A1, US20230151810A1,

US20230173415A1, US20230243792A1, US20230243801A1, US20230243802A1,

US20230243804A1, US20230266289A1, US20230266290A1, US20230273130A1, US20230273171A1, US20230273172A1, US20230273173A1, US20230304987A1,

US20230417363A1, US20230417635A1, US20240189743 Al, US20240189744A1,

US20240192112A1, US20240192708A1, US20240198331A1, US20240200547A1, PCT

Publication Nos. W02021/171120, WO2021/171121, WO2022/243792, WO2022/243797.

WO2022/243806, WO2022/243807, WO2022/243809, WO2022/259071, WO2022/259073.

WO2022/259074, WO2023/031725, WO2023/031726, WO2023/031727, W02023/042032.

W02023/042033, W02023/042035, W02023/042036, W02023/042037, W02023/042038.

W02023/042039, WO2023/161727, WO2023/161728, WO2023/170480, WO2023/170482.

WO2023/227959, WO2023/227960, WO2023/248015, WO2023/248016, WO2024/023728.

WO2024/023729, W02024/023730, and WO2024/023731, PCT Application Nos

PCT/IB2024/051283, filed 12-Feb-2024 and PCT/IB2024/051820, filed 26-Feb-2024, U.S.

Application Nos. 63/551120, filed 08-Feb-2024, 63/552730, filed 13-Feb-2024, 63/552739, filed 13-Feb-2024, 63/559305, filed 29-Feb-2024, 63/559308, filed 29-Feb-2024, 63/559312, filed 29- Feb-2024, 63/559316, filed 29-Feb-2024, 63/586486, filed 29-Sep-2023, 63/586489, filed 29-Sep- 2023, 63/586497, filed 29-Sep-2023, 63/586500, filed 29-Sep-2023, 63/586504, filed 29-Sep-

2023, 63/586510, filed 29-Sep-2023, 63/586514, filed 29-Sep-2023, 63/586524, filed 11-Oct-

2023, 63/586529, filed 29-Sep-2023, 63/586545, filed 29-Sep-2023, 63/586551, filed 29-Sep-

2023, 63/586555, filed 29-Sep-2023, 63/586562, filed 29-Sep-2023, 63/586608, filed 29-Sep-

2023, 63/586619, filed 29-Sep-2023, 63/586630, filed 29-Sep-2023, 63/586638, filed 29-Sep-

2023, 63/586656, filed 29-Sep-2023, 63/586672, filed 29-Sep-2023, 63/586702, filed 29-Sep-

2023, 63/586726, filed 29-Sep-2023, 63/586955, filed 29-Sep-2023, 63/586966, filed 29-Sep-

2023, 63/586978, filed 29-Sep-2023, 63/586984, filed 29-Sep-2023, 63/586990, filed 29-Sep-

2023, and 63/646070, filed 13-May-2024.

[0197] Referring to FIG. 52, provided is a non-limiting example of a process of calibrating the system described herein (see FIGS. 1-51). As seen in FIG. 52, a system comprising a plurality of pumps, such as a slurry pump, a diluent pump, and a standard pump, and a plurality of corresponding containers is filled with respective solutions. For instance, the slurry pump is fluidically coupled to a container filled with an agricultural sample solution, the diluent pump is fluidically coupled to a container filled with a diluent solution, and the standard pump is fluidically coupled to a container filled with a standard sample solution, such that each of the plurality of pumps can pump the respective solution. The plurality of pumps may be actuated to produce a calibration stream comprising agricultural sample solution, diluent, and/or standard sample solution. For instance, as seen in FIG. 52, the plurality of pumps may be actuated to produce a calibrations stream comprising 50 vol.% of diluent and 50 vol.% of agricultural sample, which is delivered to a plasma torch device comprising a plasma chamber and a plasma torch disposed at least partially in the plasma chamber.

[0198] The plasma torch may be ignited, e.g., to ionize the calibration stream. The calibration stream may be evaluated (e.g., analytes in the calibration stream, such as analytes of the agricultural stream, may be measured) for about 10 seconds, e.g., before varying the composition of the calibration stream.

[0199] The composition of the calibration stream may be varied over a period of time, e.g., by replacing an amount (e.g., by vol.%) of the diluent with an equivalent amount (e.g., by vol.%) of standard sample, while maintaining the amount (e.g., by vol.%) of agricultural sample in the calibration stream. The plasma formed from the calibration stream may be continuous measured.

EXAMPLES

[0200] The following are nonlimiting examples.

[0201] Example 1 - a method for utilizing an instrument adapted for analyzing an agricultural sample, the method comprising: continuously providing a calibration stream to the instrument adapted for analyzing an agricultural sample, the calibration stream having a composition that changes over a period of time.

[0202] Example 2 - the method of Example 1 further comprising: evaluating the composition of calibration stream over at least a portion of the period of time.

[0203] Example 3 - the method of Example 1 or Example 2, wherein the flow rate of the calibration stream provided to the instrument adapted for analyzing the agricultural sample is substantially constant for the evaluated period of time.

[0204] Example 4 - the method of one of Example 1 to Example 3, wherein the composition of the calibration stream continuously changes over the evaluated period of time.

[0205] Example 5 - the method of one of Example 1 to Example 3, wherein the composition of the calibration stream changes in a step wise manner over the evaluated period of time.

[0206] Example 6 - the method of any foregoing Example, wherein the composition of the calibration stream at the start of the evaluated period of time comprises an agricultural sample and a diluent. [0207] Example 7 - the method of Example 6, wherein, at the start of the evaluated period of time, the agricultural sample is present in the calibration stream in an amount from about 10 to about 60 vol.%, relative to the volume of the provided calibration stream.

[0208] Example 8 - the method of Example 6 or Example 7, wherein, at the start of the evaluated period of time, the diluent is present in the calibration stream in an amount of about 10 to about 90 vol.%, relative to the volume of the provided calibration stream.

[0209] Example 9 - the method of any foregoing Example, wherein the composition of the calibration stream at the conclusion of the evaluated period of time comprises an agricultural sample, a standard sample, and optionally a diluent.

[0210] Example 10 - the method of Example 9, wherein, at the conclusion of the evaluated period of time, the standard sample is present in the calibration stream in an amount of about 50 to about 90 vol.%, relative to the volume of the provided calibration stream.

[0211] Example 11 - the method of Example 9 or Example 10, wherein, at the conclusion of the evaluated period of time, the diluent is present in the calibration stream in an amount of 0 to about 50 vol.%, relative to the volume of the provided calibration stream.

[0212] Example 12 - the method of any foregoing Example, wherein the composition of the calibration stream comprises a substantially constant amount of the agricultural sample.

[0213] Example 13 - the method of any foregoing Example, wherein the agricultural sample comprises at least one soil particle and a carrier present in a weight ratio of the at least one soil particle to the carrier of about 3: 1.

[0214] Example 14 - the method of one of Example 2 to Example 4 and Example 6 to Example 13, wherein evaluating the calibration stream comprises determining a detected rate of change of the composition of the calibration stream.

[0215] Example 15 - the method of Example 14, wherein the detected rate of change of the composition is determined based on a rate of change of an analyte in the standard.

[0216] Example 16 - the method of Example 15, wherein the analyte is selected from potassium, sodium, magnesium, calcium, copper, iron, manganese, lithium, rhodium, thallium, indium, an ion thereof, a salt thereof, and a combination of two or more thereof.

[0217] Example 17 - the method of one of Example 14 to Example 16, wherein evaluating the calibration stream comprises identifying when the detected rate of change of the composition is substantially constant. [0218] Example 18 - the method of Example 17, wherein the detected rate of change of the composition is substantially constant if the detected rate of change of the composition does not vary by more than ±10% over a period of time of at least 1 second.

[0219] Example 19 - the method of Example 18, wherein the period of time is from 1 to 6 seconds.

[0220] Example 20 - the method of one of Example 14 to Example 17, wherein evaluating the calibration stream comprises identifying when the detected rate of change of the composition is constant.

[0221] Example 21 - the method of one of Example 14 to Example 20, wherein evaluating the calibration stream comprises determining a value of the detected rate of change of the composition when the rate of change of the composition is substantially constant or constant. [0222] Example 22 - the method of one of Example 1 to Example 8, wherein the calibration stream is free of a standard sample.

[0223] Example 23 - the method of Example 22, wherein evaluating the calibration stream comprises determining a detected background value based on assessing the calibration stream when the calibration stream is free of the standard sample.

[0224] Example 24 - the method of Example 23 further comprising calibrating the instrument using the detected background value and the value of the detected rate of change of the composition when the rate of change of the composition is substantially constant or is constant. [0225] Example 25 - the method of any foregoing Example, wherein the diluent comprises nitric acid, a hydrochloric acid, a salt thereof, or a combination of two or more thereof.

[0226] Example 26 - a method for calibrating an instrument adapted for analyzing an agricultural sample, the method comprising: continuously providing a calibration stream to the instrument adapted for analyzing an agricultural sample, the calibration stream having a composition that changes over a period of time; evaluating the composition of calibration stream over at least a portion of the period of time, wherein at the start of the evaluated period of time the composition of the calibration stream is free of a standard sample and comprises the agricultural sample and the diluent, and wherein at the conclusion of the evaluated period of time the composition of the calibration stream at comprises the agricultural sample, a standard sample, and optionally a diluent; determining a detected rate of change of the composition of the calibration stream; identifying when the detected rate of change of the composition is substantially constant; optionally, determining a value of the detected rate of change of the composition when the rate of change of the composition is substantially constant or constant; determining a detected background value based on assessing the calibration stream when the calibration stream is free of the standard sample; and calibrating the instrument using the detected background value and the value of the detected rate of change of the composition when the rate of change of the composition is substantially constant or constant.

[0227] Example 27 - the method of Example 26, wherein the flow rate of the calibration stream provided to the instrument adapted for analyzing the agricultural sample is substantially constant for the evaluated period of time.

[0228] Example 28 - the method of Example 27, wherein the flow rate of the calibration stream varies by about ±6% or less over the period of time.

[0229] Example 29 - the method of one of Example 26 to Example 28, wherein the flow rate of the calibration stream is constant over the period of time.

[0230] Example 30 - the method of any foregoing Example further comprising analyzing an amount of an analyte in the agricultural sample.

[0231] Example 31 - the method of Example 30, wherein the analyte in the agricultural sample is selected from sodium, calcium, magnesium, potassium, a salt thereof, and a combination of two or more thereof.

[0232] Example 32 - the method of any foregoing Example, wherein the agricultural sample is a soil sample.

[0233] Example 33 - a system for calibrating an instrument adapted for analyzing an agricultural sample, the system comprising: a plurality of pumps configured to provide a calibration stream having a composition that changes over a period of time to a detector; and a plasma torch device comprising a plasma chamber and a plasma torch disposed at least partially in the plasma chamber, the plasma torch being fluidly coupled to the plurality of the pumps.

[0234] Example 34 - the system of Example 33, wherein the plurality of pumps comprises a slurry pump configured to pump an agricultural sample, a standard pump configured to pump a standard sample, and a diluent pump configured to pump a diluent.

[0235] Example 35 - the system of Example 33 or Example 34, wherein at least one of the plurality of the pumps is a diaphragm pump. [0236] Example 36 - the system of one of Example 33 to Example 35, wherein each of the plurality of pumps is a diaphragm pump.

[0237] Example 37 - the system of one of Example 33 to Example 36, wherein the plasma torch device comprises a plasma chamber and a plasma torch disposed at least partially in the plasma chamber, the plasma torch being fluidly coupled to the receive the calibration stream.

[0238] Example 38 - the system of Example 37, wherein the plasma torch device is configured to discharge a pulsed flow of the calibration stream.

[0239] Example 39 - the system of Example 37, wherein the plasma torch device is configured to discharge a continuous flow of the calibration stream.

[0240] Example 40 - the system of one of Example 33 to Example 39 further comprising a spectrometer having a line of sight into the plasma chamber.

[0241] Example 41 - the system of Example 40, wherein the spectrometer is operable to detect an analyte of interest in the slurry when the pulsed flow of slurry discharged by the plasma torch is vaporized to form a gas plasma via energizing the plasma torch.

[0242] The system may repeatedly evaluate and/or determine if the detected rate of change of the composition of the calibration stream is substantially constant or constant. The system may determine if the detected rate of change of the composition of the calibration stream is substantially constant or constant as discussed above with respect to the method and/or systems disclosed herein. When the detected rate of change of the composition of the calibration stream is determined to be constant or substantially constant, the concentration of one or more analytes of the agricultural sample (such as those disclosed herein) at one or more points in time may be determined as well as the detector’s rate of change. The detector’s rate of change and/or the concentration of the one or more analytes may be used for calibration of the systems disclosed herein. In some embodiments, the plasma torch may be turned off (e.g., the flame extinguished) and the agricultural pump and respective container containing the agricultural sample cleaned.

Claims

CLAIMS What is Claimed is:

1. A method for utilizing an instrument adapted for analyzing an agricultural sample, the method comprising: continuously providing a calibration stream to the instrument adapted for analyzing an agricultural sample, the calibration stream having a composition that changes over a period of time.

2. The method of claim 1 further comprising: evaluating the composition of calibration stream over at least a portion of the period of time.

3. The method of claim 1 or claim 2, wherein the flow rate of the calibration stream provided to the instrument adapted for analyzing the agricultural sample is substantially constant for the evaluated period of time.

4. The method of one of claim 1 to claim 3, wherein the composition of the calibration stream continuously changes over the evaluated period of time.

5. The method of one of claim 1 to claim 3, wherein the composition of the calibration stream changes in a step wise manner over the evaluated period of time.

6. The method of any foregoing claim, wherein the composition of the calibration stream at the start of the evaluated period of time comprises an agricultural sample and a diluent.

7. The method of claim 6, wherein, at the start of the evaluated period of time, the agricultural sample is present in the calibration stream in an amount from about 10 to about 60 vol.%, relative to the volume of the provided calibration stream.

8. The method of claim 6 or claim 7, wherein, at the start of the evaluated period of time, the diluent is present in the calibration stream in an amount of about 10 to about 90 vol.%, relative to the volume of the provided calibration stream.

9. The method of any foregoing claim, wherein the composition of the calibration stream at the conclusion of the evaluated period of time comprises an agricultural sample, a standard sample, and optionally a diluent.

10. The method of claim 9, wherein, at the conclusion of the evaluated period of time, the standard sample is present in the calibration stream in an amount of about 50 to about 90 vol.%, relative to the volume of the provided calibration stream.

11. The method of claim 9 or claim 10, wherein, at the conclusion of the evaluated period of time, the diluent is present in the calibration stream in an amount of 0 to about 50 vol.%, relative to the volume of the provided calibration stream.

12. The method of any foregoing claim, wherein the composition of the calibration stream comprises a substantially constant amount of the agricultural sample.

13. The method of any foregoing claim, wherein the agricultural sample comprises at least one soil particle and a carrier present in a weight ratio of the at least one soil particle to the carrier of about 3:1.

14. The method of one of claim 2 to claim 4 and claim 6 to claim 13, wherein evaluating the calibration stream comprises determining a detected rate of change of the composition of the calibration stream.

15. The method of claim 14, wherein the detected rate of change of the composition is determined based on a rate of change of an analyte in the standard.

16. The method of claim 15, wherein the analyte is selected from potassium, sodium, magnesium, calcium, copper, iron, manganese, lithium, rhodium, thallium, indium, an ion thereof, a salt thereof, and a combination of two or more thereof.

17. The method of one of claim 14 to claim 16, wherein evaluating the calibration stream comprises identifying when the detected rate of change of the composition is substantially constant.

18. The method of claim 17, wherein the detected rate of change of the composition is substantially constant if the detected rate of change of the composition does not vary by more than ±10% over a period of time of at least 1 second.

19. The method of claim 18, wherein the period of time is from 1 to 6 seconds.

20. The method of one of claim 14 to claim 17, wherein evaluating the calibration stream comprises identifying when the detected rate of change of the composition is constant.

21. The method of one of claim 14 to claim 20, wherein evaluating the calibration stream comprises determining a value of the detected rate of change of the composition when the rate of change of the composition is substantially constant or constant.

22. The method of one of claim 1 to claim 8, wherein the calibration stream is free of a standard sample.

23. The method of claim 22, wherein evaluating the calibration stream comprises determining a detected background value based on assessing the calibration stream when the calibration stream is free of the standard sample.

24. The method of claim 23 further comprising calibrating the instrument using the detected background value and the value of the detected rate of change of the composition when the rate of change of the composition is substantially constant or is constant.

25. The method of any foregoing claim, wherein the diluent comprises nitric acid, a hydrochloric acid, a salt thereof, or a combination of two or more thereof.

26. A method for calibrating an instrument adapted for analyzing an agricultural sample, the method comprising: continuously providing a calibration stream to the instrument adapted for analyzing an agricultural sample, the calibration stream having a composition that changes over a period of time; evaluating the composition of calibration stream over at least a portion of the period of time, wherein at the start of the evaluated period of time the composition of the calibration stream is free of a standard sample and comprises the agricultural sample and the diluent, and wherein at the conclusion of the evaluated period of time the composition of the calibration stream at comprises the agricultural sample, a standard sample, and optionally a diluent; determining a detected rate of change of the composition of the calibration stream; identifying when the detected rate of change of the composition is substantially constant; optionally, determining a value of the detected rate of change of the composition when the rate of change of the composition is substantially constant or constant; determining a detected background value based on assessing the calibration stream when the calibration stream is free of the standard sample; and calibrating the instrument using the detected background value and the value of the detected rate of change of the composition when the rate of change of the composition is substantially constant or constant.

27. The method of claim 26, wherein the flow rate of the calibration stream provided to the instrument adapted for analyzing the agricultural sample is substantially constant for the evaluated period of time.

28. The method of claim 27, wherein the flow rate of the calibration stream varies by about ±6% or less over the period of time.

29. The method of one of claim 26 to claim 28, wherein the flow rate of the calibration stream is constant over the period of time.

30. The method of any foregoing claim further comprising analyzing an amount of an analyte in the agricultural sample.

31. The method of claim 30, wherein the analyte in the agricultural sample is selected from sodium, calcium, magnesium, potassium, a salt thereof, and a combination of two or more thereof.

32. The method of any foregoing claim, wherein the agricultural sample is a soil sample.

33. A system for calibrating an instrument adapted for analyzing an agricultural sample, the system comprising: a plurality of pumps configured to provide a calibration stream having a composition that changes over a period of time to a detector; and a plasma torch device comprising a plasma chamber and a plasma torch disposed at least partially in the plasma chamber, the plasma torch being fluidly coupled to the plurality of the pumps.

34. The system of claim 33, wherein the plurality of pumps comprises a slurry pump configured to pump an agricultural sample, a standard pump configured to pump a standard sample, and a diluent pump configured to pump a diluent.

35. The system of claim 33 or claim 34, wherein at least one of the plurality of the pumps is a diaphragm pump.

36. The system of one of claim 33 to claim 35, wherein each of the plurality of pumps is a diaphragm pump.

37. The system of one of claim 33 to claim 36, wherein the plasma torch device comprises a plasma chamber and a plasma torch disposed at least partially in the plasma chamber, the plasma torch being fluidly coupled to the receive the calibration stream.

38. The system of claim 37, wherein the plasma torch device is configured to discharge a pulsed flow of the calibration stream.

39. The system of claim 37, wherein the plasma torch device is configured to discharge a continuous flow of the calibration stream.

40. The system of one of claim 33 to claim 39 further comprising a spectrometer having a line of sight into the plasma chamber.

41. The system of claim 40, wherein the spectrometer is operable to detect an analyte of interest in the slurry when the pulsed flow of slurry discharged by the plasma torch is vaporized to form a gas plasma via energizing the plasma torch.