A calibration device and method for a capacitance tomograph for liquid flow measurement

Abstract

The application discloses a kind of for liquid flow measurement electrical capacitance tomography device and method, the calibration device includes the flow pattern identification of gas-liquid two-phase flow electrical capacitance tomography, for the pipe sealing of electrical capacitance tomography sealing system, and for the filling system of input measured fluid to electrical capacitance tomography;Sealing system includes the flange component being arranged at the both ends of electrical capacitance tomography, the port valve being arranged at the end of flange component, and the sealing member being arranged between flange component and electrical capacitance tomography;Filling system includes filling assembly, the valve assembly being arranged at filling assembly, and the liquid loading assembly being arranged at filling assembly, and filling system is connected to the flange component at the both ends of electrical capacitance tomography.The application is set by combining electrical capacitance tomography calibration device, to obtain high and low two boundary values, it is favorable to flow measurement, and device structure cost is low, recycling collection, avoid producing environmental impact.

Description

Technical Field

[0001] This invention relates to the field of liquid flow measurement technology, and in particular to a calibration device and method for a capacitance tomography imager used for liquid flow measurement. Background Technology

[0002] Gas-liquid two-phase flow is a complex nonlinear dynamic system that is widely used in petroleum, chemical, and fire protection fields. The detection of its characteristic parameters is of great significance for the control of its flow process.

[0003] Capacitive tomography (CTT) can be used to identify important characteristic parameters of gas-liquid two-phase flows, such as manifold recognition and porosity measurement. CTT technology is based on the fact that gas and liquid phases have different dielectric constants. When the distribution or concentration of each phase changes, the equivalent dielectric constant of the mixed fluid changes. Using an array of capacitive sensors, the capacitance between electrode pairs is measured, and a corresponding image reconstruction algorithm is used to reconstruct the dielectric distribution map of the measured field, which can visually display the gas-liquid two-phase distribution on the cross-section of a pipe. Due to its non-invasive nature, it has a unique advantage in characterizing two-phase flows.

[0004] Before using a capacitance tomography (CTT) system for measurements, it must be calibrated. Accurate calibration is a necessary prerequisite for obtaining key parameters such as fluid manifold, velocity, and gas-liquid distribution. Calibrator calibration typically involves performing a high and a low calibration under static conditions, corresponding to pure liquid and pure gas in a two-phase flow, respectively. The low calibration fills the pipe with the material with the lowest conductivity, typically air; the high calibration fills the pipe with the material with the highest conductivity, typically the liquid being measured. These two values ​​serve as boundary values ​​for conversion to other measurements.

[0005] For liquids such as water and oil, which are liquids at room temperature and pressure, air is generally used for propulsion. During calibration, the test liquid and air can be conveniently filled separately into the capacitance tomography (CMT) tubes to obtain two boundary values. However, for low-boiling-point fire extinguishing agents or refrigerants such as heptafluoropropane, trifluoromethane, and pentafluoroethane, which are gaseous at room temperature and pressure, and are transported in the tubes after pressurization, the flow is a two-phase gas-liquid flow. Calibration requires filling the CMT tubes with these liquids in both pure gaseous and pure liquid states, but suitable calibration devices and methods are currently lacking. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art. To achieve the above objective, a calibration device and method for a capacitance tomography imager for liquid flow measurement is provided to solve the problems mentioned in the background art.

[0007] A calibration device and method for a capacitance tomography imager for liquid flow measurement, the calibration device comprising a capacitance tomography imager for manifold identification and parameter measurement of gas-liquid two-phase flow, a sealing system for sealing the pipes of the capacitance tomography imager, and a filling system for inputting the fluid to be measured into the capacitance tomography imager.

[0008] The sealing system includes flange components disposed at both ends of the capacitance tomography imager, port valves disposed at the ends of the flange components, and a sealing element disposed between the flange components and the capacitance tomography imager.

[0009] The filling system includes a filling component, a valve component disposed on the filling component, and a liquid loading component disposed on the filling component, and the filling system is connected to flange components at both ends of the capacitance tomography imager.

[0010] As a further embodiment of the present invention: the flange component includes a first flange and a second flange disposed at both ends of the capacitance tomography imager.

[0011] As a further embodiment of the present invention: the port valve is disposed at the end of the first flange.

[0012] As a further embodiment of the present invention: the filling assembly includes a main pipe connected to the capacitance tomography imager, a vacuum pump disposed in the middle of the main pipe, a filling pump disposed at the end of the main pipe, and an air compressor disposed at the filling pump.

[0013] As a further aspect of the present invention: the liquid loading assembly includes a first storage assembly disposed at the tail end of the main pipeline, a second storage assembly disposed at the filling pump, and a collector connected to the main pipeline.

[0014] As a further aspect of the present invention: the valve assembly includes a pressure gauge disposed between the capacitance tomography imager and the main pipeline, a pressure reducing valve disposed between the first storage component and the main pipeline, an electronic scale disposed between the second storage component, a pressure relief valve disposed between the collector and the main pipeline, and a vacuum switch disposed between the vacuum pump and the main pipeline.

[0015] As a further embodiment of the present invention: the two ends of the collector are respectively connected to a port valve and a main pipeline.

[0016] Another technical solution: a calibration method for a capacitance tomography calibration device for liquid flow measurement, wherein the calibration method employs the capacitance tomography calibration device for liquid flow measurement as described above, and the specific steps of the calibration method include:

[0017] Step 1: Place the capacitance tomography imager vertically, connect it to the filling system, and set up the sealing system;

[0018] Step 2: Turn on the vacuum pump of the filling system to evacuate the pipeline of the capacitance tomography imager, then turn off the vacuum pump, turn on the second storage component to connect it to the pipeline of the capacitance tomography imager, and after the pressure gauge reading on the main pipeline stabilizes, turn on the capacitance tomography imager software and calibrate it to the lowest boundary value of the fluid to be measured.

[0019] Step 3: Restart the vacuum pump of the filling system to evacuate the pipeline of the capacitance tomography imager. Then turn off the vacuum pump, turn on the second storage component, the air compressor, and the filling pump to fill the capacitance tomography imager pipeline with liquid reagent exceeding the pipeline volume. Then turn on the nitrogen cylinder of the first storage component to pressurize it so that the pressure in the pipeline exceeds the critical pressure of the liquid being filled. After the pressure gauge reading on the main pipeline stabilizes, turn on the capacitance tomography imager software and calibrate it as the highest boundary value of the fluid to be tested.

[0020] As a further aspect of the present invention: after each calibration is completed, the fluid to be tested in the pipeline is discharged to the collector through a pressure relief valve or a port valve of the sealing system.

[0021] As a further aspect of the present invention, the calibration order of the lowest boundary value in step two and the highest boundary value in step three can be changed according to actual measurement needs.

[0022] Compared with the prior art, the present invention has the following technical advantages:

[0023] By employing the above technical solution, and through a process of first evacuating and then filling, the capacitance tomography imaging system's pipeline can be easily filled with both pure liquid and pure gaseous test fluids, obtaining two boundary values ​​(high and low), thus laying the foundation for subsequent flow measurements. The device is simple to operate; the evacuation and fluid filling steps can be easily switched, and a pressure gauge displays the internal pressure of the pipeline in real time, allowing for a direct assessment of the fluid's gas-liquid state. The calibration device includes a collector to collect the test liquid discharged from the pipeline, preventing environmental impact. Furthermore, the device is low in manufacturing cost and suitable for calibrating capacitance tomography imaging systems used for flow measurements of various low-boiling-point media such as fire extinguishing agents and refrigerants. Attached Figure Description

[0024] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings:

[0025] Figure 1 This is a schematic diagram of the calibration device according to an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the sealing system structure according to an embodiment of this application.

[0027] In the diagram: 1. Port valve; 2. First flange; 3. Seal; 4. Capacitive tomography; 5. Second flange; 6. First storage component; 7. Air compressor; 8. Second storage component; 9. Filling pump; 10. Vacuum pump; 11. Pressure reducing valve; 12. Nitrogen valve; 13. Vacuum switch; 14. Pressure relief valve; 15. Main pipeline; 16. Filling switch; 17. Pressure gauge; 18. Electronic scale; 19. Collector. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Please refer to Figure 1 and Figure 2 In this embodiment of the invention, a calibration device and method for a capacitance tomography imager for measuring liquid flow are provided. The calibration device includes a capacitance tomography imager 4, a sealing system, and a filling system.

[0030] The capacitance tomography imager 4 is used for manifold identification and parameter measurement of gas-liquid two-phase flow;

[0031] The sealing system is used to seal the pipes of the capacitance tomography imager 4;

[0032] The filling system is used to input the fluid to be measured into the capacitance tomography imager 4;

[0033] In this embodiment, the sealing system includes flange components disposed at both ends of the capacitance tomography imager 4, port valves 1 disposed at the ends of the flange components, and sealing elements 3 disposed between the flange components and the capacitance tomography imager 4.

[0034] In a specific embodiment, the flange assembly includes a first flange 2 disposed at the upper end of the capacitance tomography imager 4 and a second flange 5 disposed at the lower end. The port valve 1 is disposed at the end of the first flange 2. The sealing element 3 may specifically be a gasket for further sealing.

[0035] In this embodiment, the filling system includes a filling component, a valve component disposed on the filling component, and a liquid loading component disposed on the filling component, and the filling system is connected to flange components disposed at the upper and lower ends of the capacitance tomography imager 4.

[0036] In a specific embodiment, the filling assembly includes a main pipe 15 connected to the capacitance tomography imager 4, a vacuum pump disposed in the middle of the main pipe 15, a filling pump 9 disposed at the tail of the main pipe 15, and an air compressor 7 disposed at the filling pump 9.

[0037] In a specific embodiment, the liquid loading assembly includes a first storage assembly 6 disposed at the tail of the main pipeline 15, a second storage assembly 8 disposed at the filling pump 9, and a collector 19 connected to the main pipeline 15.

[0038] In a specific embodiment, the valve assembly includes a pressure gauge 17 disposed between the capacitance tomography imager 4 and the main pipeline 15, a pressure reducing valve 11 disposed between the first storage component 6 and the main pipeline 15, an electronic scale 18 disposed between the second storage component 8, a pressure relief valve 14 disposed between the collector 19 and the main pipeline 15, and a vacuum switch 13 disposed between the vacuum pump and the main pipeline 15.

[0039] In a specific embodiment, the first storage component 6 is a nitrogen steel tank, and the second storage component 8 is a reagent storage tank used to store the liquid to be tested, such as pentafluoroethane, heptafluoropropane fire extinguishing agent, and other liquids that need to be measured.

[0040] In a specific embodiment, the two ends of the collector 19 are connected to the port valve 1 and the main pipeline 15, respectively.

[0041] Another technical solution: a calibration method for a capacitance tomography calibration device for liquid flow measurement, wherein the calibration method employs the capacitance tomography calibration device for liquid flow measurement as described above, and the specific steps of the calibration method include:

[0042] Step 1: Place the capacitor tomography imager 4 vertically, connect it to the filling system, and set the sealing system;

[0043] Step 2: Turn on the vacuum pump of the filling system to evacuate the pipeline of the capacitance tomography imager 4, then turn off the vacuum pump, turn on the second storage component 8 to connect it to the pipeline of the capacitance tomography imager 4, and after the pressure gauge 17 on the main pipeline 15 stabilizes, turn on the software of the capacitance tomography imager 4 and calibrate it as the minimum boundary value of the fluid to be measured.

[0044] Step 3: Restart the vacuum pump of the filling system to evacuate the pipeline of the capacitance tomography imager 4. Then turn off the vacuum pump, turn on the second storage component 8, the air compressor 7, and the filling pump 9 to fill the pipeline of the capacitance tomography imager 4 with liquid reagent exceeding the pipeline volume. Then turn on the nitrogen cylinder of the first storage component 6 to pressurize the pipeline so that the pressure inside the pipeline exceeds the critical pressure of the liquid being filled. After the pressure gauge 17 on the main pipeline 15 stabilizes, turn on the software of the capacitance tomography imager 4 and calibrate it as the highest boundary value of the fluid to be tested.

[0045] In the specific steps, after each calibration is completed, the fluid to be tested in the pipeline is discharged to the collector 19 through the pressure relief valve 14 or the port valve 1 of the sealing system.

[0046] In this embodiment, the calibration order of the lowest boundary value in step two and the highest boundary value in step three can be changed according to actual measurement needs.

[0047] Example 1: Calibration of a capacitance tomography imager 4 for measuring the flow of heptafluoropropane fire extinguishing agent;

[0048] Step 1: Connect and fix the first flange 2 at the front end, the second flange 5 at the rear end, and the gasket 3 to both ends of the tomographic imager, respectively;

[0049] Step 2: Connect port valve 1 to the other end of the pipe at the first flange 2 at the front end;

[0050] Step 3: Place the capacitor tomography imager 4 vertically and connect the other end of the second flange 5 at the rear end to the main pipeline 15 of the filling system;

[0051] Step 4: Close port valve 1, turn on vacuum pump and vacuum switch 13, evacuate the pipeline of capacitive tomography imager 4, pressure gauge 17 displays the pressure change in the pipeline, and after the preset vacuum degree is reached in the pipeline, turn off vacuum switch 13 and vacuum pump in sequence.

[0052] Step 5: Open the reagent storage tank and filling switch 16 of the second storage component 8, and heptafluoropropane vapor enters the pipeline of the capacitive tomography imager 4 through the connecting pipeline;

[0053] Step 6: After the pressure gauge 17 stabilizes, close the reagent storage tank and filling switch 16 of the second storage component 8, and calibrate it using the capacitance tomography imager 4, setting it to the lowest boundary value.

[0054] Step 7: Open port valve 1 to allow the gaseous vapor in the pipeline to be discharged into collector 19.

[0055] Step 8: Turn on the vacuum pump and vacuum switch 13 again. After the pipeline reaches the set vacuum level, turn off the vacuum switch 13 and vacuum pump.

[0056] Step 9: Sequentially turn on the air compressor 7, filling pump 9, filling switch 16, and the heptafluoropropane storage tank of the second storage component 8. Monitor the mass change of the filling reagent using the electronic scale 18 located at the bottom of the storage tank. Fill the pipeline of the capacitance tomography imager 4 with liquid reagent exceeding the volume of the imager 4.

[0057] Step 10: Close the pipeline valve, the heptafluoropropane storage tank of the second storage component 8, the filling pump 9 and the air compressor 7, open the nitrogen valve 12, open the nitrogen steel tank of the first storage component 6, so that nitrogen enters the pipeline of the capacitive tomography imager 4, adjust the pressure reducing valve 11, and monitor the pressure through the pressure gauge 17 to make the pressure in the pipeline of the capacitive tomography imager 4 greater than the critical pressure of heptafluoropropane;

[0058] Step 11: After the pressure gauge 17 stabilizes, calibrate it using the software of the capacitance tomography imaging instrument 4 and set it to the highest boundary value.

[0059] Step 12: After calibration, close the nitrogen tank of the first storage component 6, close the pressure reducing valve 11, open the pressure relief valve 14, and discharge the test fluid in the pipeline to the collector 19.

[0060] Example 2: Calibration of a capacitance tomography imager 4 for measuring the flow of pentafluoroethane refrigerant;

[0061] Step 1: Connect and fix the gaskets of the first flange 2 at the front end, the second flange 5 at the rear end, and the sealing gaskets of the sealing element 3 to both ends of the tomographic imager 4 respectively;

[0062] Step 2: Connect port valve 1 (1) to the other end of the pipe at the first flange 2 at the front end;

[0063] Step 3: Place the capacitor tomography imager 4 vertically and connect the other end of the second flange 5 at the rear end to the main pipeline 15 of the filling system;

[0064] Step 4: Turn on the vacuum pump and vacuum switch 13 to evacuate the pipeline of the capacitance tomography imager 4. The pressure gauge 17 displays the pressure change in the pipeline. After the set vacuum level is reached in the pipeline, turn off the vacuum switch 13 and vacuum pump.

[0065] Step 5: Turn on the air compressor 7, filling pump 9, filling switch 16 and the pentafluoroethane storage tank of the second storage component 8 in sequence. Monitor the mass change of the filling reagent by the electronic scale 18 located at the bottom of the pentafluoroethane storage tank, and fill the pipeline of the capacitive tomography imager 44 with liquid pentafluoroethane reagent exceeding the volume of the capacitive tomography imager 44.

[0066] Step 6: Close the filling switch 16, the pentafluoroethane storage tank of the second storage component 8, the filling pump 9 and the air compressor 7, open the nitrogen valve 12, open the nitrogen steel tank, so that nitrogen enters the pipeline of the capacitive tomography imager 4, adjust the pressure reducing valve 11, and monitor the pressure in the pipeline of the capacitive tomography imager 4 through the pressure gauge 17 to make the pressure greater than the critical pressure of pentafluoroethane.

[0067] Step 7: After the pressure gauge 17 stabilizes, calibrate it using the software of the capacitance tomography imaging instrument 4 and set it to the highest boundary value;

[0068] Step 8: Close the nitrogen cylinder, close the pressure reducing valve 11, open the pressure relief valve 14, and discharge the fluid in the pipeline to the collector 19;

[0069] Step 9: Turn on the vacuum pump and vacuum switch 13 again. After the pipeline reaches the set vacuum level, turn off the vacuum switch 13 and vacuum pump. Open the reagent storage tank and filling switch 16 of the second storage component 8. The pentafluoroethane vapor enters the pipeline of the capacitive tomography imager 4 through the connecting pipeline.

[0070] Step 10: After the pressure gauge 17 stabilizes, close the tank and filling switch 16 of the second storage component 8, and calibrate it using the capacitance tomography imager 4, setting it to the lowest boundary value.

[0071] Step 11: After calibration, open port valve 1 to discharge the fluid in the pipeline to collector 19.

[0072] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention. The scope of the invention is defined by the appended claims and their equivalents, all of which should be included within the scope of protection of the invention.

Claims

1. A calibration device for a capacitance tomography imager used for measuring liquid flow, characterized in that, The calibration device includes a capacitance tomography imager for manifold identification and parameter measurement of gas-liquid two-phase flow, a sealing system for sealing the pipes of the capacitance tomography imager, and a filling system for inputting the fluid to be tested into the capacitance tomography imager. The sealing system includes flange components disposed at both ends of the capacitance tomography imager, port valves disposed at the ends of the flange components, and a sealing element disposed between the flange components and the capacitance tomography imager. The filling system includes a filling assembly, a valve assembly disposed on the filling assembly, and a liquid loading assembly disposed on the filling assembly, and the filling system is connected to flange components at both ends of the capacitance tomography imager. The filling assembly includes a main pipe connected to the capacitance tomography imager, a vacuum pump located in the middle of the main pipe, a filling pump located at the end of the main pipe, and an air compressor located at the filling pump. The liquid loading assembly includes a first storage assembly disposed at the end of the main pipeline, a second storage assembly disposed at the filling pump, and a collector connected to the main pipeline; The valve assembly includes a pressure gauge disposed between the capacitance tomography imager and the main pipeline, a pressure reducing valve disposed between the first storage component and the main pipeline, an electronic scale disposed between the second storage component, a pressure relief valve disposed between the collector and the main pipeline, and a vacuum switch disposed between the vacuum pump and the main pipeline. The calibration method based on the calibration device includes the following specific steps: Step 1: Place the capacitance tomography imager vertically, connect it to the filling system, and set up the sealing system; Step 2: Turn on the vacuum pump of the filling system to evacuate the pipeline of the capacitance tomography imager, then turn off the vacuum pump, turn on the second storage component to connect it to the pipeline of the capacitance tomography imager, and after the pressure gauge reading on the main pipeline stabilizes, turn on the capacitance tomography imager software and calibrate it to the lowest boundary value of the fluid to be measured. Step 3: Restart the vacuum pump of the filling system to evacuate the pipeline of the capacitance tomography imager. Then turn off the vacuum pump, turn on the second storage component, the air compressor, and the filling pump to fill the capacitance tomography imager pipeline with liquid reagent exceeding the pipeline volume. Then turn on the nitrogen cylinder of the first storage component to pressurize it so that the pressure in the pipeline exceeds the critical pressure of the liquid being filled. After the pressure gauge reading on the main pipeline stabilizes, turn on the capacitance tomography imager software and calibrate it as the highest boundary value of the fluid to be tested.

2. The calibration device for a capacitance tomography imager for measuring liquid flow according to claim 1, characterized in that, The flange component includes a first flange and a second flange disposed at both ends of the capacitance tomography imager.

3. The calibration device for a capacitance tomography imager for measuring liquid flow according to claim 2, characterized in that, The port valve is located at the end of the first flange.

4. The calibration device for a capacitance tomography imager for measuring liquid flow according to claim 1, characterized in that, The collector is connected at both ends to a port valve and a main pipeline, respectively.

5. The calibration device for a capacitance tomography imager for measuring liquid flow according to claim 1, characterized in that, After each calibration, the test fluid in the pipeline is discharged to the collector through the pressure relief valve or the port valve of the sealing system.

6. The calibration device for a capacitance tomography imager for measuring liquid flow according to claim 1, characterized in that, The calibration order of the minimum boundary value in step two and the maximum boundary value in step three can be changed according to actual measurement needs.

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