WO2014169319A1

WO2014169319A1 - A furnace and a method for preparing samples for sample analysis

Info

Publication number: WO2014169319A1
Application number: PCT/AU2014/000320
Authority: WO
Inventors: Boyne Friederich HOHENSTEIN
Original assignee: IMP GROUP Pty Ltd
Current assignee: IMP GROUP Pty Ltd
Priority date: 2013-04-15
Filing date: 2014-03-26
Publication date: 2014-10-23
Anticipated expiration: 2015-10-15
Also published as: AU2014253660B2; AU2014253660A1

Abstract

The present disclosure provides a furnace for preparing samples for sample analysis. The furnace comprises a housing having an interior region. Further, the furnace comprises a carousel positioned within the interior region of the housing, the carousel having a plurality of receiving portions for receiving the samples. The furnace also comprises a heater for heating the interior region of the housing and a gas distributor for distributing a gas within the interior region of the housing. The gas distributor comprises a plurality of gas outlets and the furnace is arranged such that in use each gas outlet of the plurality of gas outlets is positioned in the proximity of a sample.

Description

A FURNACE AND A METHOD FOR PREPARING SAMPLES FOR SAMPLE

ANALYSIS

Field of the Invention

The present invention broadly relates to a furnace and a method for preparing samples for sample analysis.

Background of the Invention

A variety of samples, such as mineral samples and other material samples need to be analysed in order to determine properties of the samples. The samples may be provided in the form of relatively small quantities of the material, but should have material properties that are

representative of larger quantities. It is often required to determine an initial moisture content of the samples or a dry weight of the samples, which may be determined form a rate of weight loss during the drying process. However, the drying process i.s dependent on various parameters and simultaneous drying of a number of samples in a furnace at uniform conditions is still a challenge.

Summary of the Invention The present invention provides in a first aspect a furnace for preparing samples for sample analysis, the furnace comprising :

a housing having an interior region; a carouse.], positioned within the interior region and having a plurality of receiving portions for receiving the samples ;

a heater for heating the interior region of the housing; and

a gas distributor having at least one gas inlet and a plurality of gas outlets for distri.buti.ng the gas;

wherein the furnace is arranged such that in use each gas outlet is positioned in the proximity of a sample.

Embodiments of the invention have significant advantages. By positioning each of the plurality of gas outlets in the proximity of a sample, the drying process of the samples when positioned in the receiving stations of the carousel may be accelerated.

The furnace may be arranged such that in use the gas distribution is substantially uniform at the locations of the samples. Further, the furnace may be arranged such that gas that gas is directed to the samples from positions above the samples.

The furnace may be arranged such that the number of receiving stations equals the number of gas outlets of the gas distributor.

In one embodiment the furnace is arranged such that each sample is in use positioned in close proximity of a respective gas outlet of the plurality of gas outlets. Each gas outlet may be positioned above a respective receiving station such that the gas outlet is positioned over a respective sample when a sample is positioned in the receiving station. In an alternative embodiment the plurality of gas outlets comprises groups of gas outlets and in use each sample is positioned in close proximity of a respective group of gas outlets.

In some embodiments, the gas distributor comprises an interior region for guiding the gas from the ab least one gas inlet to the gas outlets and the interior region is otherwise closed.

The plurality of gas outlets may be in the form of apertures that may comprise respective valves. In a specific embodiment, the gas distributor is substantially disc shaped. However, any other suitable shape of the gas distributor is envisaged.

The gas distributor may be insertable into and/or removable from the furnace. For example, the gas distributor may be retrofitted to the furnace.

In one embodiment, the gas distributor is a component of the carousel. In this embodiment, the carousel may be insertable into and/or removable from the furnace.

Alternatively, the gas distributor may be separate from the carousel .

The housing of the furnace may also comprise a lid or a wall portion that comprises the gas distributor. The gas may be nitrogen. However, any other suitable gas or gas composition is envisaged. For example, the gas may be dried air. The receiving stations of the carousel may be arranged to receive crucibles in which the samples are positioned.

The interior region of the housing may comprise sealed wall portions and may be arranged such that the gas can only enter the interior region through the plurality of gas outlets and only exit the interior region through an exit port. The exit port may have a position that is selected such that the gas distribution is substantially uniform when the gas flows through the interior region of the furnace.

In one example, wall portions of the furnace comprise a metallic material. The wail portions may be hermetically sealed.

In one embodiment, the furnace comprises a component for determining a weight of a sample. In one specific example the component is arranged to determine a change in weight of a sample (typically with a crucible) during drying, which may be indicative of an initial moisture content of the sample.

In embodiments in which the interior region comprises sealed wall portions, the component for determining the weight of the sample may be positioned within the interior region of the housing. The carousel may be arranged to rotate the samples about an axis when the samples are positioned in the receiving stations . In one embodiment, the furnace comprises a mechanism for moving crucibles into or out of a respective receiving station. For example, that mechanism may be arranged, to move the crucibles in a direction that has a component perpendicular zo the rotational axis about which the carousel is arranged to move the crucibles . In one example, the mechanism is arranged to move the crucibles in a substantially horizontal direction.

In an alternative embodiment, the mechanism, for moving the crucibles is arranged to move the crucibles in a direction that has a component parallel to the rotational axis about which the carousel is arranged to move the crucibles. The gas distributer may have at least one passageway through which a crucible can be moved.

The heater may be arranged to heat the samples, such as a suitable mixture of a mineral sample material and a flux, to a temperature sufficient to effect melting of the samples .

The furnace may comprise a control system that is arranged to control operation of components of the furnace such as at least one of the heater, the carousel, the gas distributor, the component for determining a weight, and the mechanism for moving the crucibles. The control system may be arranged such that heat treatment, rotation of the carousel, the gas distribution and the weighing is performed in an automated manner. Furthermore, the control system may be arranged such that Loading and unloading the receiving stations with respective crucibles is performed in an automated manner. The control system may also be arranged such that parameters are selectable by a user. For example, the parameters may include a rotation or an oscillation rate of the carousel, a temperature of the furnace, a duration of the heat treatment or a duration of the gas

distribution.

The control system in accordance with an embodiment of the present invention comprises a timer for timing a period of time during which the samples are exposed to the heat treatment and/or a flow of the gas. The control system with the timer may be arranged to interrupt the heat treatment and/or the gas distribution after a

predetermined time or effect an alarm signal. The control system may comprise a memory device for storing control parameters.

In one embodiment, the carousel is one of a plurality of carousels. For example a first carousel may be positioned over a second carousel and arranged for rotation about the same axis.

In a second aspect of the present invention, there is provided an insert for a furnace for preparing samples for sample analysis, the furnace comprising a heater and a housing that has an interior region in which a carousel is positioned, the carousel having a plurality of receiving stations for receiving the samples, the insert comprising: at least one gas inlet; and a plurality of gas outlets for distributing the gas; wherein the furnace is arranged such that in use each gas outlet is positioned in the proximity of a sample. The insert may be arranged such that the gas is directed to the samples from positions above the samples .

The insert may be arranged such that the number of receiving stations is equal to the number of gas outlets of the insert.

In one embodiment each sample is in use positioned in close proximity of a respective gas outlet of the plurality of gas outlets. Each gas outlet may be

positioned above a respective receiving station such that the gas outlet is positioned over a respective sample when a sample is positioned in the receiving station.

Alternatively, the plurality of gas outlets may comprise groups of gas outlets and each sample may in use be positioned in close proximity of a respective group of gas outlets .

In some embodiments, the insert comprises an interior region for guiding the gas to the gas outlets and the interior region is otherwise closed.

The insert may be separate from the carousel.

Alternatively, the insert comprises the carousel.

In one embodiment, the insert is arranged such that in use the gas distribution is substantially uniform. The insert may be substantially disc shaped.

The plurality of gas outlets may comprise respective valves .

The insert may form a part of a lid or wall portion of a housing of the furnace.

The present invention provides in a third aspect a method of preparing samples for sample analysis, the method comprising the steps of:

providing a plurali^ty of samples positioned at a plurality of receiving stations of a carousel in an interior region of a furnace;

exposing the samples to heat treatment; and distributing a gas within the interior region of the furnace from a plurality of gas outlets such that the gas is directed to each sample from a respective position or a respective group of positions.

The method may further comprise a step of inserting the gas distributor into zhe furnace.

In at least some embodiments, the method comprises a step of drying the gas prior to distributing the gas within the interior region.

The method may comprise a step of determining a weight of a sample. Further, the method may comprise determining a change in weight of the sample during drying of the sample in order to determine an initial moisture content of the sample . The method may be conducted in. an automated

manner. Further, the method may comprise selecting parameters, such as a temperature of the furnace, duration of the gas distribution or duration of the heat

treatment .

The method may comprise heating the samples to a temperature above the melting point of the sample. The invention will be more fully understood from the following description of specific embodiments of the invention by way of example only. The description is provided with reference to the accompanying drawings. Brief Description of the Drawings

Figure 1 shows schematic cross-sectional view of a furnace for preparing samples in accordance with an embodiment of the present invention;

Figures 2a and 2b show schematic perspective views of a gas distributor of the furnace of Figure 1;

Figures 3 and 4 show schematic cross-sectional views of a furnace in accordance with a further embodiment of the invention;

Figure 5 shows a schematic perspective view of a furnace into which an insert in accordance with embodiments of the invention may be inserted; and Figure 6 is s flow chart illustrating a method of preparing samples in accordance with an embodiment of the present invention. Detailed Description of Specific Embodiments

Embodiments of the present invention relate to a furnace and an insert for a furnace for preparation of samples, such as mineral samples. In one embodiment the furnace is arranged to dry a plurality of samples, such as mineral samples, at substantially uniform conditions.

Referring initially to Figure 1, a furnace 100 for preparing samples for sample analysis is now described. The furnace 100 comprises a housing 102 having an interior region in which a carousel 104 is positioned. The carousel 104 is arranged for rotation about an axis and drivable by a drive 106 of the carousel 104. The carousel 104 has a plurality of receiving stations that each have an aperture and the apertures are positioned in a ringlike manner along the periphery of the carousel 104. Each aperture of a receiving station is sized to receive and hold a crucible 108. The crucible 108 has a radial lip that extends in a ring-like manner at an upper portion of the crucible 108 and which rests on the carousel 104 when the crucible 108 is positioned in a respective receiving station 106.

In one embodiment the furnace 100 further comprises a heater 109 for heating samples to a temperature suitable for drying of the samples and may also be arranged for melting the samples to generate fused (homogenised) samples that form a homogeneous glass bead when cooled and are suitable for various analysis techniques. The samples for fusion may for example include mined materials (in powder form) or any other type of material that is suitably prepared. Sample preparation includes mixing a sample material with a flux material and receiving a resultant mixture into the crucibles 108.

A person skilled in the art will appreciate that in alternative embodiments the heater 109 may not necessarily be arranged for fusion of the samples, but may

alternatively be arranged for heating che samples to a lower temperature, such as a temperature that is

sufficient for reducing a moisture content of the samples. The furnace 100 also comprises a gas distributor 110 which is shown in more detail and isolated from the furnace 100 in Figure 2. In this embodiment, the gas distributor 110 is located within the interior region of the housing 102 of the furnace 100. However, it will be appreciated and illustrated further below that the gas distributor 110 may be in the form of an insert that is irisertable into a furnace. In this way, the gas distributor may be retrofitted with a conventional furnace. Referring back to Figure 1, the gas distributor 110 is arranged to distribute a gas within the interior region of the housing 102. The qas is suitable for drying a material sample. Examples of a suitable gas or suitable gases are nitrogen and. dried air. However, any other suitable is envisaged.

In this embodiment, the gas distributor 110 is

substantially disc shaped and comprises a gas inlet 112 and a plural ity of gas outl ets 114 in form of a plurality of apertures that are positioned in close proximity to respective samples in the crucibles 108. In this example, the gas distributor 110 has an interior space 116 that can be filled with the gas which in this particular example is a nitrogen gas. As such, the nitrogen gas is directed into the space 116 through the gas inlet 112 and exits the space 116 through the plurality of apertures 114. Each aperture of the plurality of apertures 114 is positioned above a respective sample in a crucible such that the nitrogen gas is distributed into the crucible 108 onto a top surface of the sample. In this way, the drying process of the samples in the crucibles 108 may be accelerated. Furthermore, by positioning each of the apertures 114 in close proximity to a respective sample in a crucible 108 a substantially uniform gas distribution to the samples may be achieved. A person skilled in the art will appreciate that other arrangements of the plurality of gas outlets 114 relative to respective samples is envisaged. For example, each gas outlet may be positioned lateral to or below the

respective sample.

The number of apertures in the gas distributor 110 may or be equal to the number of receiving stations .

Consequently, if the receiving stations are fully loaded with samples in crucibles 108, the number of samples will be equal to the number of apertures.

In the embodiment shown in Figure 1, the interior region 117 of the housing 102 in which the carousel 104 with the .samples is positioned comprises sealed metallic wail portions. In this particular embodiment, the interior region 117 is arranged, such that the gas can only enter the interior region 117 through the plurality of apertures 114 and can only exit the interior region through an exit port (not shown) . The gas flows through the interior region 117 in a controlled manner without leaking into components of the furnace 100. Providing sealed wall portions in which the carousel 104 is positioned has the advantage of providing a more uniform gas distribution throughout the interior region 117 compared to

conventional furnaces that are typically made of porous ceramic material. In this way, moisture content may be removed from the samples in a uniform manner.

The furnace 100 further comprises a mechanism 118 for moving a crucible 108 relative to a receiving station of the carousel 104. In this particular embodiment, the mechanism 118 is in form of a piston 118 arranged for moving a crucible 108 in an upward or downward direction. In this way, by moving a crucible 108 in an upward direction, the crucible 108 may be moved out of a respective receiving station and to an exterior location of the furnace 100. Similarly, by moving a crucible 108 in a downward direction, the crucible 108 can be moved from an exterior location of the furnace 100 to a respective receiving station of the carousel 104.

For moving a crucible 108 in the above described way, the gas distributor 110 further comprises a passageway 120 for facilitating passage of the crucible 108. The passageway 120 in this embodiment is in form of an aperture.

However, other forms are envisaged. In variations of the described embodiment, the furnace 100 may also comprise more than one carousel 104 and the carousels may be positioned over one another and arranged for rotation about a common axis driven by the drive 106. In this case the furnace 100 comprises a suitable means for moving all carousels up and down such that the arms 112 and 114 are able co operate as described above.

Alternatively, the furnace 100 may also comprise more than one mechanism for moving the crucibles 108 and the mechanisms may be stacked on top of one another in the same manner as the carousels.

In a further embodiment (not shown), the carousel 104 is removable from the furnace 100 so that more than one furnace can be used. For example, the carousel 104 may be moved from a first furnace being heated to a first temperature such as 105°C to a second furnace being heated to a second temperature. As such, the samples may be heated through various temperature ranges.

Referring now to Figures 3 and 4 there is shown a front view and a corresponding plan view along the line BB of Figure 4 of a furnace 300 in accordance with a further embodiment of the present invention. Like reference numerals in Figures 3 and 4 denote like parts of the furnace 100 shown in Figure 1.

The furnace 300 comprises the heater 109 and the housing 102 in which the carousel 104 with the samples contained in crucibles 108 is positioned. The interior region of the furnace 300 also comprises sealed wall portions such that the gas flows through the interior region in a controlled manner. However, a. person skilled .in the art will appreciate that in other embodiments the interior region of the housing may be sealed such that the gas is captured .

The furnace 300 further comprises a component 322 for determining a weight of a sample. The component 322 is in form of: a balance 322 that can weigh samples through various temperature ranges and periods of gas

distribution. By determining a weight loss of a sample, for example over a period of time, the moisture content of the sample may be determined. In this particular embodiment, the balance 322 is located within the interior region with the sealed wall portions such that the gas does not leak into portions of the balance 322.

Further, the furnace 300 comprises the piston 118 for moving a crucible in an upward or downward position. As such, the gas distributor 110 also comprises the aperture 120 so that the crucible 108 can be moved to or from an exterior location. The piston 118 is also located within the interior region having the sealed wall portions. The furnace 300 comprises a sealing lid 324 that is positioned so that the aperture 120 can be sealed.

With reference to Figure 5, there is shown a furnace 500 into which an insert in accordance with an embodiment of the invention is insertable. Like reference numerals in Figure 5 denote like parts of the furnace 100 shown in Figure 1. As mentioned above, the gas distributor 110 as shown in Figure 2 may be provided in form of an insert that is insertable into the furnace 500 or any other suitable furnace. Tn this way, the gas distributor may be retrofitted into an existing furnace.

The furnace 500 also comprises a mechanism 510 for moving crucibles 108, for example between respective receiving stations 106 and a location that is exterior to the housing 102. Tn this particular embodiment, the mechanism 510 moves the crucibles in a substantially horizontal direction. The mechanism 510 comprises a first arm 512 and a second arm 514. The first arm 512 is arranged for moving the crucibles 108 from the exterior position to a respective receiving station 106 of the carousel 104. The second arm 514 is arranged for moving the crucibles 108 out of respective receiving stations and to the exterior location. However, a person skilled in the art will appreciate that any suitable mechanism for moving the crucibles is envisaged. For example, the furnace 300 may comprise a single arm that moves a crucible from and to a respective receiving station. Alternatively, the crucibles may be moved manually.

The housing 102 of the furnace 500 has an access port 516 at a side portion through which the arms 512 and 514 move the crucibles 108.

For this particular embodiment, the gas distributor 110 shown in Figure 2 may be provided without the passageway 120 as by moving the crucibles 108 in a substantially horizontal direction, a passage for crucibles through the gas distributor may not be required.

It will be appreciated by a person skilled in the art that not only the gas distributor 110 in form of the insert may be insertable into and/or removable from the furnace 500, but also the carousel 104.

The furnace 100, 300, 500 also comprises control electronics (not shown) that is arranged to allow automated operation of the furnace. Further, the furnace comprises temperature sensors (not shown) and is arranged such that a user can select a temperature and a time for the heat treatment ana the gas distribution. These parameters may be preselected and the control electronics is arranged to operate in accordance with the pre-selected parameters in an automated manner. Consequently, the control electronics controls operation of the drive 103, the heater 109, the carousel 104, the gas distributor 110 and the mechanism 118, 510.

A person skilled in the art will appreciate that any combinations cf parts of the embodiments shown in the Figures are envisaged. For example, the furnace 100 may comprise the mechanism 300 for moving crucibles in a substantially horizontal direction.

Referring now to Figure 6, a flow chart of a method 600 of preparing samples for sample analysis in a furnace in accordance with a specific embodiment of the present invention is now described. The furnace may for example be the above-described furnace 300. The method 600 comprises an initial step 602 of providing a plurality of crucibles with samples that are positioned at a plurality of receiving stations of a carousel in an interior region of a furnace. In a next step 604, the samples are exposed to heat treatment, for example, the samples may be heated through various temperature ranges starting with a temperature of 105°C. However, other temperature ranges are envisaged. During or subsequent to the heat treatment, a gas that is suitable for drying a sample such as dry nitrogen gas is distributed into the interior region of the furnace from a plurality of gas outlets of a gas distributor (606) . Each of the plurality of gas outlets is positioned in close proximity to a respective sample for drying the sample. Prior to the gas

distribution seep 606, the gas may be treated so that it is suitable for drying a sample (607) .

In this particular embodiment, che method further comprises a step 608 of determining a weight of a sample.

This step may be repeated until constant mass of the sample is retained or until a preset time period has elapsed. In a further step 610 a moisture content of the sample is determined, for example by determining a weight loss over time. The method is conducted in an automated manner.

Having described a specific embodiments of "he invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments and that various changes and modifications could be effected therein by one skilled in the art without departing from the spirit or scope of the invention as defined in the appended claims. In the claims which follow and in the preceding

description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Claims

Claims :

1. A furnace for preparing samples for sample analysis, the furnace comprising:

a housing having an interior region;

a carousel positioned within the interior region and having a plurality of receiving portions for receiving the samples ;

a heater for heating' the interior region of the housing; and

a gas distributor having at least one gas inlet and a plurality of gas outlets for distributing the gas;

2. The furnace of claim 1 wherein the furnace is arranged such that in use the gas distribution is substantially uniform at the locations of the samples.

3. The furnace of claim 1 or 2 wherein the furnace is arranged such that gas that gas is directed to the samples from positions above rhe samples.

4. The furnace of any one of the preceding claims wherein the furnace is arranged such that each sample is in use positioned in close proximity of a respective gas outlet of the plurality of gas outlets.

5. The furnace of any one of claims 1 to 3 wherein the plurality of gas outlets comprises groups of gas outlets and wherein in use each sample is positioned in close proximity of a respective group of gas outlets .

6. The furnace of any one of the preceding claims wherein the gas distributor comprises an interior region through which the gas can be directed to the plurality of gas outlets and the interior region is otherwise closed.

7. The furnace of any one of the preceding claims wherein the receiving stations of the carousel are arranged to receive crucibles in which the samples are positioned.

8. The furnace of any one of the preceding claims wherein the gas distributor is substantially disc shaped.

9. The furnace of any one of the preceding claims wherein the interior region of the housing comprises sealed wall portions and is arranged such that the gas can only enter the interior region through the plurality of gas outlets and only exit the interior region through an exit port.

10. The furnace of any one of the preceding claims wherein the gas distributor is a component of the carousel .

11. The furnace of any one of the preceding claims comprising a component for determining a weight of a sample .

12. The furnace of any one of the preceding claims comprising a mechanism for moving a crucible into or out of a respective receiving station.

1.3. The furnace of any one of the preceding claims comprising a control system that is arranged to control operation of components of the furnace such as at least one of the heater, the carousel, the gas distributor, a component for determining a weight, and a mechanism for moving the crucibles .

14. An insert for a furnace for preparing samples for sample analysis, the furnace comprising a heater and a housing that has an interior region in which a carousel is positioned, the carousel having a plurality of receiving stations for receiving the samples, the insert comprising: at least one gas inlet; and

a plurality of gas outlets for distributing the gas; wherein the furnace is arranged such that in use each gas outlet is positioned in the proximity of a sample.

15. The insert of claim 14 wherein the insert is arranged such that the gas is directed to the samples from positions above the samples.

16. The insert of claim 14 or 16 wherein in use each sample is positioned in close proximity of a respective gas outlet of the plurality of gas outlets .

17. The insert of claim 14 or 16 wherein the plurality of gas outlets comprises groups of gas outlets and wherein in use each sample is positioned in close proximity of a respective group of gas outlets.

IS. The insert of any one of claims 14 to 17 wherein the insert comprises an interior region for guiding the gas to the gas outlets and the .Interior region is otherwise closed.

19. The insert of any one of claims 14 to 18 wherein the insert comprises the carousel.

20. The insert of any one of claims 14 to 19 wherein the receiving stations of the carousel, are arranged to receive crucibles in which the samples are positioned.

21. The insert of any one of claims 14 to 20 wherein the insert is arranged such that in use the gas distribution is substantially uniform within the interior region of the hou s i ng .

22. The insert of any one of claims 14 to 21 being substantially disc shaped.

23. The insert of any one of claims 14 to 22 forming a part of a lid of a housing of the furnace.

24. A method of preparing samples for sample analysis, the method comprising the steps of:

providing a plurality of samples positioned at a plurality of receiving stations of a carousel in an interior region of a furnace;

25. The method of claim 24 further comprising a step of inserting the gas distributor into the furnace .

26. The method of claim 24 or 25 comprising a step of drying the gas prior ~o distributing the gas within the interior region.

27. The method of any one of claims 24 to 25 comprising step of determining a weight and/or a change in weight of a sample.

28. The method of any one of claims 24 to 27 being conducted in an automated manner.