WO1991019171A1 - Fluid level detector system and apparatus - Google Patents
Fluid level detector system and apparatus Download PDFInfo
- Publication number
- WO1991019171A1 WO1991019171A1 PCT/AU1991/000242 AU9100242W WO9119171A1 WO 1991019171 A1 WO1991019171 A1 WO 1991019171A1 AU 9100242 W AU9100242 W AU 9100242W WO 9119171 A1 WO9119171 A1 WO 9119171A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- fluid
- signal
- container
- level
- tube
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
- G01F23/296—Acoustic waves
- G01F23/2962—Measuring transit time of reflected waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
- G01F23/284—Electromagnetic waves
Definitions
- the present invention relates to an apparatus and method for the measurement of fluid level.
- the invention has particular application to the measurement of the fluid level in a container, though it is to be understood it is not restricted thereto, while a container may include a discrete vessel or an enclosure such as a dam.
- the present invention seeks to overcome these disadvantages in the prior art or at least to ameliorate them by providing a substantially more flexible and accurate measurement of fluid level in a container.
- the invention comprises an apparatus for determining the level of fluid in a container including waveguide means for extending into a fluid, means for transmitting a signal down said waveguide means, means for receiving a reflection of said signal from said fluid through which said waveguide means passes in use, means for measuring as a function of the transmission of said signal and reception of said reflection the length along said waveguide means of said fluid.
- a method of determining the level of a fluid including the steps of: placing a tube into said fluid with a length of tube extending from said fluid; transmitting a signal down said tube; receiving a reflection of said signal corresponding to reflection from the fluid boundary; measuring the time delay between the transmission and reception of said signal and determining the length along said tube at which said boundary occurs.
- the signal comprises an ultrasonic or other sonic signal but could also include an electromagnetic signal.
- plastic tubing acts as a suitable wave guide for the signal.
- an apparatus for determining the level of a fluid including tubular means, open at one end, for extending into a fluid, means for transmitting a signal down said tubular means, means for receiving a reflection of said signal from a surface of said fluid through which said tubular means passes in use, means for measuring the time delay between a transmission of said signal and reception of said reflection, and means to convert said time delay to a measure of length along said tubular means at which said reflection occurred.
- a simple symmetrical container in the form of a beaker 10 is filled with liquid to a level 12.
- the top 20 of the spiral tube 14 is then connected via section 22 with an acoustic matching section 24 which matches the tube 14 to an acoustic receiver/ transmitter 26.
- the receiver/transmitter 26 is of any standard form and is designed to be operated at a suitable acoustic frequency.
- the receiver/transmitter 26 operates at ultrasonic frequencies above human or other animate hearing sensitivities.
- the receiver/transmitter 26 also incorporates circuitry as is well known in the Sonar or Radar art for determining the duration or time delay between a pulse being transmitted and a reflection or echo being returned.
- a signal propagating down the tube 22 into the spiral 14 will encounter the surface of the fluid at level
- the open end 16 of spiral 14 enables the fluid in the container to fill the tube to the height of the fluid in the rest of the container.
- the tube for example in parts 22 and 20 above level of the liquid 12, for example, is filled with air and the mismatch in impedance between this medium and the liquid in the container results in the transmitted signal from the receiver/transmitter 26 being reflected at the interface between these two media.
- the fact that the propagation path is enclosed within a tube results in an echo which is conserved by being concentrated within the tube rather than being scattered as in existing acoustic techniques.
- a very small bleed hole (not shown) can be provided in the measurement tube 14, usually close to the transmitter/receiver apparatus in section 22. This hole allows pressure equalisation between the measurement tube and the surrounding atmosphere. Its size would be chosen to provide a damping effect against sudden changes in fluid height, while minimising signal loss from the measurement system.
- the propagation path of the signal as the liquid level decreases is substantially great.
- the sensitivity of the measurement can be enhanced compared with a purely depth measurement.
- it may be useful to have the spiral other than conform to the shape of the container for example a conical form may be used such that the diameter of the turns of the spiraling increase with increasing depth of the container to enable a greater sensitivity to be obtained at lower liquid levels.
- a conical form may be used such that the diameter of the turns of the spiraling increase with increasing depth of the container to enable a greater sensitivity to be obtained at lower liquid levels.
- irregular that shape may be the fluid in the tube accurately reflects at all times the level of liquid within the container irrespective of the orientation of the container.
- An alternative embodiment can employ the spiral tube as the wall of the container with suitable sealing of the turns to provide a fluid tight enclosure.
- the open end of the tube can then comprise an aperture in the tube at its lowest point.
- the use of a coil avoids any need for computing any compensation with irregularly shaped containers.
- the pitch and/or the diameter of the coil is adjusted at the appropriate places of the container to automatically linearize the measurement. This latter aspect makes it ideal as a linear feed back sensor in a control system for tank filling, particularly where the tank is shallow or irregularly shaped.
- An alternative acoustic method to that described above uses commonly known electronic techniques to determine the resonant acoustic frequency of the gas column within the measurement tube 14.
- the schematic representation of such a system is the same as shown in Figure 1.
- the power required to propagate a signal of given strength within the gas column is a function of frequency, and is a minimum at the resonant frequencies of the gas column. These frequencies in turn depend on the distance to the liquid level 12 or, in general, the point of reflection of the signal. Determining the minimum in the power curve as a function of frequency and applying knowledge of the relationship between resonant frequency and length of the gas column will give the height of the liquid.
- the commonly known techniques include Automatic Frequency Tracking, Frequency Chirping, and other like techniques within the knowledge of persons skilled in the art.
- An automatic frequency tracking system can also provide a very convenient feedback signal for process control systems.
- figure 1 was described with respect to the liquid in a container.
- the invention is equally applicable to determining the level of a gas in a container with the tubing between the horn matching section 24 and the level of the gas being filled with some other fluid whether a gas or liquid of suitable density.
- the method is different to that used for liquid measurements.
- the boundary reflection would take place at the base 18 of the chamber or container (or end of the tube 16).
- the transit time for the pulse and echo would vary in relation to the mixture of gases in the measurement tube.
- the tube 14 could comprise a hollow tube wound into a suitable form provided with a reflective coating on the inside.
- a flexible tube can be employed dimensioned as required for the particular frequency of operation as is well known in the art.
- a (solid) fibre optic cable from which the outer refractive layer had been stripped can be used.
- the fluid e.g. liquid
- the refractive index of the fluid is higher than that of the plastics or glass material of the fibre optic cable, some of the signal is returned to the cable by the fluid from which returned signal the depth (extent) of the fluid can be determined using interferometry.
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Thermal Sciences (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
Apparatus to measure the level (12) of liquid in a container (10) using a coiled tube (14) open at the end (16) situated at the base (18) of the container. An acoustic signal or electromagnetic signal is transmitted down tube (14) from transmitter/receiver (26). By determining the point at which reflection occurs using the time delay for an echo or resonance within lengths (20, 22) of tube (14), the level (12) is measured. By shaping the coil to the container a linear measure can be achieved even for an irregularly shaped container. It can also measure the level of unmixed or immiscible gases.
Description
FLUID LEVEL DETECTOR SYSTEM AND APPARATUS
Technical Field
The present invention relates to an apparatus and method for the measurement of fluid level. The invention has particular application to the measurement of the fluid level in a container, though it is to be understood it is not restricted thereto, while a container may include a discrete vessel or an enclosure such as a dam.
Background of the Invention
A variety of methods and apparatus exist for the determination of the level of a fluid. These prior art methods have included ultrasonic ranging to the fluid boundary, the use of floats operating mechanical or electrical sensors or the use of electrical measurements where the fluid bridges contacts in an electrical circuit having an electrical parameter such as resistance which varies along the length of the contacts.
Each of these known techniques have disadvantages and are often inaccurate in that they often can only determine the average level of the fluid by measuring its value at one point in the vessel or container. For a vessel or container which is of an unusual or complex shape and where the container may be subject to movement the sensor arrangement may provide a very unreliable measurement. The measurement generally involves or depends upon a non-linear function.
If a resonance technique is used to measure length ambiguity exists as to which mode is being measured, whether the fundamental or an harmonic.
Statement of the Invention
The present invention seeks to overcome these disadvantages in the prior art or at least to ameliorate them by providing a substantially more flexible and accurate measurement of fluid level in a container.
In its broadest form, the invention comprises an apparatus for determining the level of fluid in a container including waveguide means for extending into a fluid, means for transmitting a signal down said waveguide means, means for receiving a reflection of said signal from said fluid through which said waveguide means passes in use, means for measuring as a function of the transmission of said signal and reception of said reflection the length along said waveguide means of said fluid.
In one aspect according to the invention there is provided a method of determining the level of a fluid including the steps of: placing a tube into said fluid with a length of tube extending from said fluid; transmitting a signal down said tube; receiving a reflection of said signal corresponding to reflection from the fluid boundary; measuring the time delay between the transmission and reception of said signal and determining the length along said tube at which said boundary occurs. Preferably the signal comprises an ultrasonic or other sonic signal but could also include an electromagnetic signal. In the case of a sonic signal plastic tubing acts as a suitable wave guide for the signal.
According to a further aspect of the invention there is provided an apparatus for determining the level of
a fluid including tubular means, open at one end, for extending into a fluid, means for transmitting a signal down said tubular means, means for receiving a reflection of said signal from a surface of said fluid through which said tubular means passes in use, means for measuring the time delay between a transmission of said signal and reception of said reflection, and means to convert said time delay to a measure of length along said tubular means at which said reflection occurred.
Description of the Drawing
A preferred embodiment of the invention will now be described with respect to the figure, in which a spiral tube measures the depth of fluid in a cylindrical container.
BEST MODE FOR CARRYING OUT THE INVENTION
As shown a simple symmetrical container in the form of a beaker 10 is filled with liquid to a level 12. A tube 14 having an open end 16 wound as a tight spiral from the base 18 of the container up to a height at which liquid is to be retained in the container. The top 20 of the spiral tube 14 is then connected via section 22 with an acoustic matching section 24 which matches the tube 14 to an acoustic receiver/ transmitter 26. The receiver/transmitter 26 is of any standard form and is designed to be operated at a suitable acoustic frequency.
Preferably the receiver/transmitter 26 operates at ultrasonic frequencies above human or other animate hearing sensitivities. The receiver/transmitter 26 also incorporates circuitry as is well known in the Sonar or Radar art for determining the duration or
time delay between a pulse being transmitted and a reflection or echo being returned.
A signal propagating down the tube 22 into the spiral 14 will encounter the surface of the fluid at level
12. The open end 16 of spiral 14 enables the fluid in the container to fill the tube to the height of the fluid in the rest of the container. The tube for example in parts 22 and 20 above level of the liquid 12, for example, is filled with air and the mismatch in impedance between this medium and the liquid in the container results in the transmitted signal from the receiver/transmitter 26 being reflected at the interface between these two media. The fact that the propagation path is enclosed within a tube results in an echo which is conserved by being concentrated within the tube rather than being scattered as in existing acoustic techniques.
A very small bleed hole (not shown) can be provided in the measurement tube 14, usually close to the transmitter/receiver apparatus in section 22. This hole allows pressure equalisation between the measurement tube and the surrounding atmosphere. Its size would be chosen to provide a damping effect against sudden changes in fluid height, while minimising signal loss from the measurement system.
As the tube is wound in conformity with the shape of the container, in this case a cylinder the propagation path of the signal as the liquid level decreases is substantially great. Depending on the pitch and diameter of the spiral which is also dependent on the size or diameter of the tube the sensitivity of the measurement (resolution) can be enhanced compared with a purely depth measurement.
In some embodiments it may be useful to have the spiral other than conform to the shape of the container for example a conical form may be used such that the diameter of the turns of the spiraling increase with increasing depth of the container to enable a greater sensitivity to be obtained at lower liquid levels. However if the tube is made to conform to the shape of the container however irregular that shape may be the fluid in the tube accurately reflects at all times the level of liquid within the container irrespective of the orientation of the container.
An alternative embodiment can employ the spiral tube as the wall of the container with suitable sealing of the turns to provide a fluid tight enclosure. The open end of the tube can then comprise an aperture in the tube at its lowest point.
The use of a coil avoids any need for computing any compensation with irregularly shaped containers. The pitch and/or the diameter of the coil is adjusted at the appropriate places of the container to automatically linearize the measurement. This latter aspect makes it ideal as a linear feed back sensor in a control system for tank filling, particularly where the tank is shallow or irregularly shaped.
An alternative acoustic method to that described above uses commonly known electronic techniques to determine the resonant acoustic frequency of the gas column within the measurement tube 14. The schematic representation of such a system is the same as shown in Figure 1. In general principles, the power required to propagate a signal of given strength within the gas column is a function of frequency, and is a minimum at the resonant frequencies of the gas column. These frequencies in turn depend on the
distance to the liquid level 12 or, in general, the point of reflection of the signal. Determining the minimum in the power curve as a function of frequency and applying knowledge of the relationship between resonant frequency and length of the gas column will give the height of the liquid. To determine and track the resonances a number of techniques are known. The commonly known techniques include Automatic Frequency Tracking, Frequency Chirping, and other like techniques within the knowledge of persons skilled in the art. An automatic frequency tracking system can also provide a very convenient feedback signal for process control systems.
The embodiment of figure 1 was described with respect to the liquid in a container. The invention is equally applicable to determining the level of a gas in a container with the tubing between the horn matching section 24 and the level of the gas being filled with some other fluid whether a gas or liquid of suitable density. When used for gas level measurements with an acoustic pulse/echo mode (as supra) the method is different to that used for liquid measurements. When used for gas levels, the boundary reflection would take place at the base 18 of the chamber or container (or end of the tube 16). However the transit time for the pulse and echo would vary in relation to the mixture of gases in the measurement tube. For example when a heavier than air gas leaks into a bilge, bunker or chamber which normally contains only breathable air, the heavier than air gas sinks to the bottom of the chamber, enters the measurement tube and displaces a portion of the breathable air. The transit time for the signal will change. Prior calibration can then relate the magnitude of this change to the height of gas in the chamber.
In the case of an optical signal the tube 14 could comprise a hollow tube wound into a suitable form provided with a reflective coating on the inside.
To operate using a radio frequency, microwave or other electromagnetic signal a flexible tube can be employed dimensioned as required for the particular frequency of operation as is well known in the art.
In the particular case of an optical signal a (solid) fibre optic cable from which the outer refractive layer had been stripped can be used. The fluid (e.g. liquid) replaces the outer layer of the fibre optic cable. When the refractive index of the fluid is higher than that of the plastics or glass material of the fibre optic cable, some of the signal is returned to the cable by the fluid from which returned signal the depth (extent) of the fluid can be determined using interferometry.
Though the invention has been described above with respect to a preferred embodiment thereof other variations of the invention are contemplated within the knowledge of a person skilled in the art.
Claims
1. An apparatus for determining the level of fluid in a container including waveguide means for extending into a fluid, means for transmitting a signal down said waveguide means, means for receiving a reflection of said signal from said fluid through which said waveguide means passes in use, means for measuring as a function of the transmission of said signal and reception of said reflection the length along said waveguide means of said fluid.
2. An apparatus for determining level of fluid in a container as claimed in claim 1 wherein said waveguide means includes tubular means, open at one end, for extending into said fluid, said reflection of said signal is from a surface of said fluid through which said tubular means passes in use, and said means for measuring measures the time delay between a transmission of said signal and reception of said reflection, and converts said time delay to a measure of length along said tubular means at which said reflection occurred.
3. An apparatus as claimed in claim 2 wherein said tubular means is in a coiled form.
4. An apparatus as claimed in claim 3 wherein said coiled tubular means is shaped to fit said container in which said fluid is constrained.
5. An apparatus as claimed in claim 4 wherein said signal is an acoustic signal.
6. An apparatus as claimed in claim 4 wherein said signal is an electromagnetic signal and said tubular means confines said electromagnetic signal to propagate therealong.
7. An apparatus as claimed in claim 4 wherein said coiled tubular means has a variable radius.
8. An apparatus as claimed in claim 7 wherein said fluid, the level of which is to be measured, is a liquid.
9. An apparatus as claimed in claim 7 wherein said fluid, the level of which is to be measured, is a gas
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPK0502 | 1990-06-05 | ||
| AUPK050290 | 1990-06-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1991019171A1 true WO1991019171A1 (en) | 1991-12-12 |
Family
ID=3774736
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/AU1991/000242 Ceased WO1991019171A1 (en) | 1990-06-05 | 1991-06-05 | Fluid level detector system and apparatus |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO1991019171A1 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002001211A1 (en) * | 2000-06-28 | 2002-01-03 | The University Of Western Australia | Microwave measurement of phase equilibria |
| WO2005038415A1 (en) * | 2003-10-15 | 2005-04-28 | Axsensor Ab | Fluid level measurement device |
| DE102005044143A1 (en) * | 2005-09-15 | 2007-03-29 | Siemens Ag | Filling medium e.g. water, level measurement device for use in chemical industry, has line arrangement for guiding measurement serving electromagnetic waves with propagation characteristics, and designed as electromagnetic delay line |
| CN100442028C (en) * | 2003-10-15 | 2008-12-10 | 艾克森塞股份公司 | Fluid position measuring device and method |
| EP2310814A4 (en) * | 2008-08-07 | 2014-01-15 | Illinois Tool Works | Liquid level sensing system |
| DE102012218574A1 (en) * | 2012-10-11 | 2014-04-17 | Frima - T Sas | Sensor for measuring e.g. level of water in container of cooking apparatus based on time-domain reflectometry principle, has metal probe surrounded with dielectric material, and coupling device comprising magnet for fastening sensor at wall |
| DE102014214346A1 (en) | 2014-07-23 | 2016-01-28 | BSH Hausgeräte GmbH | household appliance |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3330059A1 (en) * | 1983-08-19 | 1985-02-28 | Siemens AG, 1000 Berlin und 8000 München | Filling-level gauge for liquid containers |
| US4641139A (en) * | 1984-04-25 | 1987-02-03 | Saab Marine Electronics Aktiebolag | Method and apparatus for measuring the level of a fluent material in a container |
| US4909080A (en) * | 1987-10-31 | 1990-03-20 | Toyoda Gosei Co., Ltd. | Ultrasonic level gauge |
-
1991
- 1991-06-05 WO PCT/AU1991/000242 patent/WO1991019171A1/en not_active Ceased
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3330059A1 (en) * | 1983-08-19 | 1985-02-28 | Siemens AG, 1000 Berlin und 8000 München | Filling-level gauge for liquid containers |
| US4641139A (en) * | 1984-04-25 | 1987-02-03 | Saab Marine Electronics Aktiebolag | Method and apparatus for measuring the level of a fluent material in a container |
| US4641139B1 (en) * | 1984-04-25 | 1998-04-14 | Saab Marine Electronics | Method and apparatus for measuring the level of a fluent material in a container |
| US4909080A (en) * | 1987-10-31 | 1990-03-20 | Toyoda Gosei Co., Ltd. | Ultrasonic level gauge |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6879166B2 (en) | 2000-06-28 | 2005-04-12 | University Of Western Australia | Microwave measurement of phase equilibria |
| WO2002001211A1 (en) * | 2000-06-28 | 2002-01-03 | The University Of Western Australia | Microwave measurement of phase equilibria |
| US7856876B2 (en) | 2003-10-15 | 2010-12-28 | Axsensor Ab | Fluid level measurement device |
| WO2005038415A1 (en) * | 2003-10-15 | 2005-04-28 | Axsensor Ab | Fluid level measurement device |
| EP1962066A3 (en) * | 2003-10-15 | 2008-09-03 | Axsensor AB | Fluid level measurement device |
| CN100442028C (en) * | 2003-10-15 | 2008-12-10 | 艾克森塞股份公司 | Fluid position measuring device and method |
| US7571645B2 (en) | 2003-10-15 | 2009-08-11 | Axsensor Ab | Fluid level measurement device |
| DE102005044143A1 (en) * | 2005-09-15 | 2007-03-29 | Siemens Ag | Filling medium e.g. water, level measurement device for use in chemical industry, has line arrangement for guiding measurement serving electromagnetic waves with propagation characteristics, and designed as electromagnetic delay line |
| EP2310814A4 (en) * | 2008-08-07 | 2014-01-15 | Illinois Tool Works | Liquid level sensing system |
| DE102012218574A1 (en) * | 2012-10-11 | 2014-04-17 | Frima - T Sas | Sensor for measuring e.g. level of water in container of cooking apparatus based on time-domain reflectometry principle, has metal probe surrounded with dielectric material, and coupling device comprising magnet for fastening sensor at wall |
| DE102012218574B4 (en) | 2012-10-11 | 2019-10-24 | Rational Wittenheim Sas | sensor |
| DE102014214346A1 (en) | 2014-07-23 | 2016-01-28 | BSH Hausgeräte GmbH | household appliance |
| DE102014214346B4 (en) * | 2014-07-23 | 2020-09-03 | BSH Hausgeräte GmbH | Home appliance |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102224398B (en) | System and method for filling level determination | |
| CN106338332B (en) | System and method for measuring the speed of sound in liquid or gaseous media | |
| KR940000144B1 (en) | Liquid level measuring device in container | |
| US7965087B2 (en) | Method for ascertaining and monitoring fill level of a medium in a container | |
| US5309763A (en) | Liquid-level gauging | |
| JP4773028B2 (en) | Microwave level transmitter proximity substance interface detection method | |
| US3695107A (en) | Method of measuring the level of a material in a tank, and an apparatus for practicing this method | |
| US5062295A (en) | Dual tube sonic level gage | |
| JP2005514586A (en) | Measuring signal evaluation method of measuring device based on propagation time | |
| US20080060431A1 (en) | Radar level gauging | |
| JPH05231905A (en) | Distance measuring equipment and method | |
| CN102047082A (en) | Method for Determining Interference Echo Distribution of Radar Level Meter System | |
| US20050241391A1 (en) | Targeted guided wire level measuring device | |
| US9279705B2 (en) | High temperature high pressure seal | |
| EP2901145A1 (en) | Emulsion measurement and profiling system and method | |
| EP3704451B1 (en) | Radar level gauge system and method for interface measurement | |
| CN103261854B (en) | Determination of medium properties for level measurement | |
| US9638568B2 (en) | Weight apparatus for a waveguide, probe apparatus, and method for manufacturing a weight apparatus | |
| CN109357729B (en) | A method for measuring liquid interface level based on guided wave radar level gauge | |
| WO1991019171A1 (en) | Fluid level detector system and apparatus | |
| US5099691A (en) | Method for measuring length, and apparatus for implementing the method | |
| US12104943B2 (en) | Guided wave radar level gauge and method for controlling the guided wave radar level gauge | |
| JPS63158423A (en) | Sensor for detecting moving characteristic of material in vessel and conduit and detecting emthod | |
| US5184512A (en) | Measuring the length of a column of fluid in a tube | |
| US20230228612A1 (en) | Level gauge and method for sensing material levels in tanks |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| AK | Designated states |
Kind code of ref document: A1 Designated state(s): AU CA JP US |
|
| AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK ES FR GB GR IT LU NL SE |
|
| NENP | Non-entry into the national phase |
Ref country code: CA |