A static mass method calibration device and method for ultra-low temperature liquid

Abstract

The present invention discloses a static mass method calibration device for ultra-low temperature liquids and a method thereof, wherein the static mass method calibration device for ultra-low temperature liquids comprises a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a meter to be tested, a cryogenic protection tank, a weighing tank, a cryogenic tank, a cryogenic storage tank, a power source, a reversing valve group, a scale, and a lifting mechanism. The static mass method calibration device for ultra-low temperature liquids provided by the present invention can avoid frost on the weighing tank mouth and its attached pipes, can also avoid gasification of cryogenic liquids in the weighing tube, and can also avoid direct contact between sensors such as scales and storage tanks, thereby ensuring the stability and accuracy of the measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of flow detection, and in particular to a static mass method calibration device and method for ultra-low temperature liquid. Background Art

[0002] Natural gas is a clean energy. It is our national energy policy to realize the diversification, cleanliness, efficiency and low carbonization of energy. The development of natural gas vehicle and ship industry is one of the concrete manifestations. Natural gas also has the greatest growth potential among civilian energy sources. This is the case with trade measurement, which is the first choice, followed by flowmeters. However, flowmeters can only be selected for process measurement in automobile refueling. How to ensure the measurement error of flowmeters, in addition to the stability and accuracy of the flowmeter itself, the actual flow calibration close to the medium state is very important. The critical temperature of liquefied natural gas under normal pressure is -162℃. Considering that natural gas is flammable and explosive, the general method is to use liquid nitrogen with a higher safety factor for calibration. The critical temperature of liquid nitrogen under normal pressure is -196℃, which is sufficient to meet the calibration needs. The current calibration method is mainly to compare with each other, and there is an Emerson flowmeter as a standard table for comparison.

[0003] The dynamic mass method used by the National Institute of Standards and Technology of the United States has a system expanded uncertainty of 0.17%, k = 2. The static mass method can provide the uncertainty level of the calibration system. The difficulties of the existing low-temperature calibration device are as follows: frost on the weighing tank mouth and the attached pipes (pre-cooling of water molecules in the air), vaporization of cryogenic liquid in the weighing tube (the volume of cryogenic liquid is about 1 to several hundred of the same amount of gas volume), sealing devices, the weight of the weighing (metering) tank, and the scale sensor cannot directly contact the storage tank. Summary of the invention

[0004] In order to solve the limitations and defects of the prior art, the present invention provides a static mass method calibration device for ultra-low temperature liquids, comprising a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a meter to be tested, a cryogenic protection tank, a weighing tank, a cryogenic tank, a cryogenic storage tank, a power source, a reversing valve group, a scale, and a lifting mechanism;

[0005] The bottom of the low-temperature protection tank is connected to the power source through the third valve. The low-temperature protection tank is made of a vacuum tank. The weighing tank is arranged at the upper part of the low-temperature protection tank. The low-temperature protection tank is used to store the low-temperature medium used for calibration. The weighing tank is low-temperature protected to prevent the weighing tank from frosting.

[0006] The weighing tank is loaded with the measured liquid, the top of the weighing tank is connected to the scale, the bottom of the weighing tank is connected to the reversing valve group, the reversing valve group and the lifting mechanism form a reversing system, the scale is used to weigh the weight of the liquid, the upper part of the scale is connected to the lower end of the lifting mechanism, the lower part of the scale is connected to the weighing tank through three connecting rods to avoid transmitting low temperature to the weighing sensor, and the top of the lifting mechanism is fixed on an immovable object;

[0007] The weighing tank is connected to one end of the inspected meter through the first valve, and the other end of the inspected meter is connected to the cryogenic tank through the second valve. The cryogenic tank is used to cool the recovered liquid. One end of the cryogenic tank is connected to a low-temperature storage tank through the fifth valve, and the other end of the cryogenic tank is connected to the power source. The low-temperature storage tank is connected to the power source through the fourth valve, and the low-temperature storage tank is used to provide low-temperature liquid used for calibration.

[0008] Optionally, the power source is a cryogenic pump or a compressor.

[0009] Optionally, the reversing valve group includes a sealing block, a connecting rod mechanism, a liquid guide hole, a sealing joint surface, a weighing tank, and an ejector pin;

[0010] The sealing block is connected to the liquid diversion hole through the connecting rod mechanism, the weighing tank is arranged below the sealing block, the weighing tank is fixedly connected to the liquid diversion hole, the sealing joint surface is arranged between the sealing block and the weighing tank, the ejector pin is arranged below the weighing tank, the ejector pin and the sealing block are arranged opposite to each other, and the ejector pin and the connecting rod mechanism are on the same axis.

[0011] Optionally, the outer shell of the cryogenic tank is made using vacuum.

[0012] The present invention also provides a method for calibrating a super-low temperature liquid by static mass method, wherein the method uses any of the above-mentioned super-low temperature liquid static mass method calibrating devices, and the method comprises:

[0013] The third valve and the fifth valve are closed, the first valve, the second valve and the fourth valve are opened, the power source is started, and the liquid enters the cryogenic tank to cool the liquid. The liquid after entering the cryogenic tank enters the meter under test to ensure the low temperature state of the liquid and prevent the liquid from heating up and gasifying. The lifting mechanism in the reversing system falls, the reversing valve group is opened, and the liquid entering the weighing tank flows into the low temperature protection tank. When the liquid reaches the preset liquid level, the precooling of the meter under test is completed;

[0014] Close the first valve, open the fifth valve, close the reversing system, lift the scale, and read the tare weight Q of the weighing tank after the scale reading stabilizes. ij ;

[0015] The fifth valve is closed, the first valve is opened, the reversing system is opened, and after the flow rate is stabilized, the reversing system is closed, the cryogenic liquid is in the weighing tank, and the control system starts counting to measure the number of pulses output by the meter under test;

[0016] When the number of pulses reaches a preset value, the first valve is closed, the fifth valve is opened, and the control system ends counting N. ij , read Q1 after the reading of the scale stabilizes ij ;

[0017] Open the reversing system to drain the liquid in the weighing tank. If the liquid in the low-temperature protection tank is higher than the preset liquid level, close the fourth valve and open the third valve. When the liquid in the low-temperature protection tank drops to the preset liquid level, close the third valve and open the fourth valve to continue extracting liquid from the low-temperature storage tank.

[0018] The fourth valve and the second valve are closed, and the third valve and the fifth valve are opened, so that the liquid flows from the low-temperature protection tank into the cryogenic tank, and returns to the cryogenic storage tank after being cooled in the cryogenic tank.

[0019] Optionally, the cumulative mass measured by the ultra-low temperature liquid static mass method verification device is: Qs ij =Q1 ij -Q0 ij , the cumulative pulse number of the meter under test is: Q ij =N ij / K, the error calculation formula for a single calibration is as follows:

[0020]

[0021] Among them, Q ij Qs is the cumulative pulse number of the meter under test, ij It is the cumulative mass measured by the ultra-low temperature liquid static mass method calibration device.

[0022] Optionally, also include:

[0023] When the lifting mechanism lifts the scale, the scale drives the weighing tank to be lifted, the sealing block is separated from the ejector pin, and under the action of the spring of the connecting rod mechanism, the sealing block moves downward, and the sealing block is combined with the sealing joint surface to play a sealing role;

[0024] When the lifting mechanism is lowered, the weighing tank moves downward under the action of gravity, and the ejector pin pushes the sealing block to move upward, a gap is generated between the sealing joint surface and the sealing block, and the liquid flows out through the gap.

[0025] The present invention has the following beneficial effects:

[0026] The static mass method calibration device for ultra-low temperature liquid provided by the present invention comprises a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a meter to be tested, a cryogenic protection tank, a weighing tank, a cryogenic tank, a cryogenic storage tank, a power source, a reversing valve group, a scale, and a lifting mechanism. The static mass method calibration device for ultra-low temperature liquid provided by the present invention can avoid frost on the weighing tank mouth and its attached pipes, can also avoid gasification of cryogenic liquid in the weighing tube, and can also avoid direct contact between sensors such as scales and storage tanks, thereby ensuring the stability and accuracy of the measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the structure of the ultra-low temperature liquid static mass method calibration device provided in Example 1 of the present invention.

[0028] Figure 2 This is a schematic diagram of a first state of the ultra-low temperature liquid static mass method calibration device provided in Example 1 of the present invention.

[0029] Figure 3 This is a schematic diagram of a second state of the ultra-low temperature liquid static mass method calibration device provided in Example 1 of the present invention.

[0030] Figure 4 This is a schematic diagram of the third state of the ultra-low temperature liquid static mass method calibration device provided in Example 1 of the present invention.

[0031] Figure 5 This is a schematic diagram of a fourth state of the ultra-low temperature liquid static mass method calibration device provided in Example 1 of the present invention.

[0032] Figure 6 This is a block diagram of a static mass method calibration device for ultra-low temperature liquids provided in Example 1 of the present invention.

[0033] Figure 7 This is a schematic diagram of the structure of the reversing valve group provided in Example 1 of the present invention.

[0034] Among them, the accompanying drawings are marked as: the first valve-11, the second valve-12, the third valve-13, the fourth valve-14, the fifth valve-15, the inspected meter-20, the low-temperature protection tank-21, the weighing tank-22, the deep freezing tank-23, the low-temperature storage tank-24, the power source-30, the reversing valve group-31, the scale-32, the lifting mechanism-33, the sealing block-1, the connecting rod mechanism-2, the liquid guide hole-3, the sealing joint surface-4, and the ejector pin-6. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solution of the present invention, the ultra-low temperature liquid static mass method calibration device and method provided by the present invention are described in detail below in conjunction with the accompanying drawings.

[0036] Embodiment 1

[0037] Figure 1 This is a schematic diagram of the structure of the ultra-low temperature liquid static mass method calibration device provided in Example 1 of the present invention. Figure 2 This is a schematic diagram of a first state of the ultra-low temperature liquid static mass method calibration device provided in Example 1 of the present invention. Figure 3 This is a schematic diagram of a second state of the ultra-low temperature liquid static mass method calibration device provided in Example 1 of the present invention. Figure 4 This is a schematic diagram of the third state of the ultra-low temperature liquid static mass method calibration device provided in Example 1 of the present invention. Figure 5 This is a schematic diagram of the fourth state of the ultra-low temperature liquid static mass method calibration device provided in the first embodiment of the present invention. Figure 1-5 As shown, this embodiment provides a static mass method calibration device for ultra-low temperature liquids, including a first valve 11, a second valve 12, a third valve 13, a fourth valve 14, a fifth valve 15, a meter to be tested 20, a cryogenic protection tank 21, a weighing tank 22, a cryogenic tank 23, a cryogenic storage tank 24, a power source 30, a reversing valve group 31, a scale 32, and a lifting mechanism 33. The static mass method calibration device for ultra-low temperature liquids provided in this embodiment can prevent frost on the weighing tank mouth and its attached pipes, prevent the cryogenic liquid from gasifying in the weighing tube, and prevent the scale and other sensors from directly contacting the storage tank, thereby ensuring the stability and accuracy of the measurement.

[0038] In this embodiment, the bottom of the low-temperature protection tank 21 is connected to the power source 30 through the third valve 13. The low-temperature protection tank 21 is made of a vacuum tank. The weighing tank 22 is arranged at the upper part of the low-temperature protection tank 21. The low-temperature protection tank 21 is used to store the low-temperature medium used for calibration, and the weighing tank 22 is low-temperature protected to prevent the weighing tank 22 from frosting.

[0039] Figure 6 This is a block diagram of a static mass method test device for ultra-low temperature liquids provided in the first embodiment of the present invention. Figure 6As shown, the weighing tank 22 is loaded with the measured liquid, the top end of the weighing tank 22 is connected to the scale 32, the bottom end of the weighing tank 22 is connected to the reversing valve group 31, the reversing valve group 31 and the lifting mechanism 33 form a reversing system, the scale 32 is used to weigh the weight of the liquid, the upper part of the scale 32 is connected to the lower end of the lifting mechanism 33, the lower part of the scale 32 is connected to the weighing tank 22 through three connecting rods to avoid transmitting low temperature to the weighing sensor, and the top end of the lifting mechanism 33 is fixed on an immovable object.

[0040] In this embodiment, the weighing tank 22 is connected to one end of the inspected meter 20 through the first valve 11, and the other end of the inspected meter 20 is connected to the cryogenic tank 23 through the second valve 12. The cryogenic tank 23 is used to cool the recovered liquid. One end of the cryogenic tank 23 is connected to the low-temperature storage tank 24 through the fifth valve, and the other end of the cryogenic tank 23 is connected to the power source 30. The low-temperature storage tank 24 is connected to the power source 30 through the fourth valve 14. The low-temperature storage tank 24 is used to provide low-temperature liquid used for calibration.

[0041] Figure 7 This is a schematic diagram of the structure of the reversing valve group provided in the first embodiment of the present invention. Figure 7 As shown, the power source 30 is a cryogenic pump or a compressor, and the reversing valve group 31 includes a sealing block 1, a connecting rod mechanism 2, a liquid diversion hole 3, a sealing joint surface 4, a weighing tank 22, and a ejector pin 6; the sealing block 1 is connected to the liquid diversion hole 3 through the connecting rod mechanism 2, the weighing tank 22 is arranged below the sealing block 1, the weighing tank 22 is fixedly connected to the liquid diversion hole 3, the sealing joint surface 4 is arranged between the sealing block 1 and the weighing tank 22, the ejector pin 6 is arranged below the weighing tank 22, the ejector pin 6 is arranged opposite to the sealing block 1, the ejector pin 6 and the connecting rod mechanism 2 are on the same axis, and the outer shell of the cryogenic tank 23 is made of vacuum.

[0042] See also Figure 1-5 , 5 valves are used to control the on and off of the pipeline, and change the flow direction of the medium in the pipeline as needed. The power source can be a cryogenic pump or a compressor. The low-temperature protection tank is made of a vacuum tank, which is used to store the low-temperature medium for calibration, and to protect the weighing tank from frosting. The weighing tank provided in this embodiment, also known as the metering tank, is connected to the scale and is used to load the liquid to be tested. The outer shell of the deep freezing tank is made of vacuum, which is used to cool the recovered liquid. The cryogenic storage tank is used to provide the cryogenic liquid required for calibration, and the reversing valve group and the lifting machine form a reversing system. The scale is used to weigh the liquid, connected to the lifting mechanism upward, and connected to the weighing tank through three connecting rods downward to prevent the low temperature from being transmitted to the weighing sensor. The lifting mechanism is fixedly set on an immovable object, and the prompt mechanism is connected to the scale.

[0043] The ultra-low temperature liquid static mass method calibration device provided in this embodiment includes a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a meter to be tested, a cryogenic protection tank, a weighing tank, a cryogenic tank, a cryogenic storage tank, a power source, a reversing valve group, a scale, and a lifting mechanism. The ultra-low temperature liquid static mass method calibration device provided in this embodiment can avoid frost on the weighing tank mouth and its attached pipes, and can also avoid the cryogenic liquid from gasifying in the weighing tube, and can also avoid the scale and other sensors from directly contacting the storage tank, thereby ensuring the stability and accuracy of the measurement.

[0044] Embodiment 2

[0045] This embodiment provides a method for calibrating ultra-low temperature liquid static mass method, which uses the ultra-low temperature liquid static mass method calibration device provided in the first embodiment. The specific content can be referred to the description of the first embodiment above, which will not be repeated here.

[0046] See also Figure 2 The ultra-low temperature liquid static mass calibration method provided in this embodiment includes: closing the third valve 13 and the fifth valve 15, opening the first valve 11, the second valve 12, and the fourth valve 14, starting the power source 30, and the liquid enters the cryogenic tank 23 to cool the liquid. After entering the cryogenic tank 23, the liquid enters the inspected meter 20 to ensure the low temperature state of the liquid and prevent the liquid from heating up and gasifying. The lifting mechanism 33 in the reversing system falls, and the reversing valve group 31 opens. The liquid entering the weighing tank 22 flows into the low temperature protection tank 21. When the liquid reaches the preset liquid level, the precooling of the inspected meter 20 is completed.

[0047] See also Figure 3 , close the first valve 11, open the fifth valve 15, close the reversing system, lift the scale 32, and read the tare weight Q0 of the weighing tank 22 after the reading of the scale 32 stabilizes. ij The ultra-low temperature liquid static mass method calibration device provided in this embodiment can prevent frost on the weighing tank mouth and its attached pipes, prevent the low temperature liquid from vaporizing in the weighing tube, and prevent the weighing sensor from directly contacting the storage tank, thereby ensuring the stability and accuracy of the measurement.

[0048] See also Figure 4 , close the fifth valve 15, open the first valve 11, open the reversing system, and after the flow rate stabilizes, close the reversing system. The cryogenic liquid is in the weighing tank 22, and the control system starts counting to measure the number of pulses output by the meter under test 20. When the number of pulses reaches a preset value, close the first valve 11, open the fifth valve 15, and the control system ends counting Nij , read Q1 after the reading of the scale 32 stabilizes ij The reversing system is opened to drain the liquid in the weighing tank 22. If the liquid in the low temperature protection tank 21 is higher than the preset liquid level, the fourth valve 14 is closed and the third valve 13 is opened. When the liquid in the low temperature protection tank 21 drops to the preset liquid level, the third valve 13 is closed and the fourth valve 14 is opened to continue extracting liquid from the low temperature storage tank 24.

[0049] See also Figure 5 , close the fourth valve 14 and the second valve 12, open the third valve 13 and the fifth valve 15, and the liquid flows from the low-temperature protection tank 21 into the cryogenic tank 23, and returns to the cryogenic storage tank 24 after being cooled by the cryogenic tank 23.

[0050] In this embodiment, the cumulative mass measured by the ultra-low temperature liquid static mass method verification device is: Qs ij =Q1 ij -Q0 ij , the cumulative pulse number of the meter under test 20 is: Q ij =N ij / K, the error calculation formula for a single calibration is as follows:

[0051]

[0052] Among them, Q ij is the cumulative pulse number of the meter under test 20, Qs ij It is the cumulative mass measured by the ultra-low temperature liquid static mass method calibration device.

[0053] See also Figure 7 The static mass method for ultra-low temperature liquid verification provided in this embodiment also includes: when the lifting mechanism 33 lifts the scale 32, the scale 32 drives the weighing tank 22 to be lifted, the sealing block 1 is separated from the ejector pin 6, and under the action of the spring of the connecting rod mechanism 2, the sealing block 1 moves downward, and the sealing block 1 is combined with the sealing joint surface 4 to play a sealing role. When the lifting mechanism 33 is lowered, the weighing tank 22 moves downward under the action of gravity, and the ejector pin 6 pushes the sealing block 1 to move upward, and a gap is generated between the sealing joint surface 4 and the sealing block 1, and the liquid flows out through the gap.

[0054] The steps of liquid filling into the cryogenic protection tank and precooling the meter under test provided in this embodiment are as follows: close the third valve 13 and the fifth valve 15, open the first valve 11, the second valve 12, and the fourth valve 14, start the power source, and in order to ensure the temperature of the liquid and prevent the liquid from heating up and vaporizing, the liquid enters the cryogenic tank 23 before entering the meter under test to cool the liquid, the lifting mechanism 33 in the reversing system falls, the reversing valve group opens, and the liquid entering the weighing tank flows into the cryogenic protection tank 21. When the liquid reaches a liquid level sufficient for protection, the precooling of the meter under test is completed and the process ends.

[0055] The steps of weighing the weighing tank provided in this embodiment are as follows: after the precooling is completed, the first valve 11 is closed, the fifth valve 15 is opened, the reversing system is closed, the scale 32 is lifted, and the tare weight Q of the weighing tank is read after stabilization. ij .

[0056] After the step of weighing the weighing tank, in this embodiment, the fifth valve 15 is closed, the first valve 11 is opened, the reversing system is turned on, and after the flow rate stabilizes, the reversing system is closed, and the cryogenic liquid exists in the weighing tank. At the same time, the control system starts counting (measuring the number of output pulses of the meter under test).

[0057] When the preset value is reached, the first valve 11 is closed, the fifth valve 15 is opened, and the control system ends counting N at the same time. ij , read Q1 after the scale reading stabilizes ij After weighing, the reversing system is opened to drain the liquid in the weighing tank 22. If the liquid level in the low temperature protection tank 21 is high, the fourth valve 14 is closed and the third valve 13 is opened. When the liquid level drops to a reasonable position, the third valve 13 is closed and the fourth valve 14 is opened to continue taking liquid from the storage tank.

[0058] The steps of liquid recovery provided in this embodiment are as follows: during the liquid recovery process, the fourth valve 14 and the second valve 12 are closed, the third valve 13 and the fifth valve 15 are opened, and the liquid is cooled from the low-temperature protection tank 21 through the deep freezing tank 23 and then returns to the low-temperature storage tank 24.

[0059] In this embodiment, the device measures the cumulative mass as Qs ij =Q1 ij -Q0 ij ;

[0060] The accumulated number of the inspected tables is Q ij =N ij / K;

[0061] The error of a single test is as follows:

[0062]

[0063] See also Figure 6 and Figure 7The reversing valve group provided in this embodiment, because the weighing tank is in a low-temperature gas protection state, the actuators of both pneumatic valves and electric valves cannot work at low temperatures. The working principle is as follows:

[0064] When the lifting mechanism lifts the scale, the weighing tank is lifted because the scale is still connected to the weighing tank, and the sealing block is separated from the ejector pin. At the same time, the sealing block is pushed downward by the spring of the connecting rod mechanism, and the sealing block is combined with the sealing surface to play a sealing role;

[0065] On the contrary, when the lifting mechanism is lowered, the weighing tank moves downward due to gravity, the ejector pin pushes the sealing block upward, a gap is generated between the sealing surface and the sealing block, and the liquid flows out.

[0066] The static mass method for calibrating ultra-low temperature liquids provided in this embodiment uses a static mass method for calibrating ultra-low temperature liquids, which includes a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a meter to be tested, a cryogenic protection tank, a weighing tank, a cryogenic tank, a cryogenic storage tank, a power source, a reversing valve group, a scale, and a lifting mechanism. The static mass method for calibrating ultra-low temperature liquids provided in this embodiment can prevent frost on the weighing tank mouth and its attached pipes, prevent the cryogenic liquid from vaporizing in the weighing tube, and prevent the scale and other sensors from directly contacting the storage tank, thereby ensuring the stability and accuracy of the measurement.

[0067] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A static mass method calibration device for ultra-low temperature liquids, characterized in that: It includes the first valve, the second valve, the third valve, the fourth valve, the fifth valve, the meter under test, the cryogenic protection tank, the weighing tank, the cryogenic tank, the cryogenic storage tank, the power source, the reversing valve group, the scale, and the lifting mechanism; The bottom of the low-temperature protection tank is connected to the power source through the third valve. The low-temperature protection tank is made of a vacuum tank. The weighing tank is arranged at the upper part of the low-temperature protection tank. The low-temperature protection tank is used to store the low-temperature medium used for calibration. The weighing tank is low-temperature protected to prevent the weighing tank from frosting. The weighing tank is loaded with the measured liquid, the top of the weighing tank is connected to the scale, the bottom of the weighing tank is connected to the reversing valve group, the reversing valve group and the lifting mechanism form a reversing system, the scale is used to weigh the weight of the liquid, the upper part of the scale is connected to the lower end of the lifting mechanism, the lower part of the scale is connected to the weighing tank through three connecting rods to avoid transmitting low temperature to the weighing sensor, and the top of the lifting mechanism is fixed on an immovable object; The weighing tank is connected to one end of the inspected meter through the first valve, the other end of the inspected meter is connected to the cryogenic tank through the second valve, the cryogenic tank is used to cool the recovered liquid, one end of the cryogenic tank is connected to the low-temperature storage tank through the fifth valve, the other end of the cryogenic tank is connected to the power source, the low-temperature storage tank is connected to the power source through the fourth valve, and the low-temperature storage tank is used to provide low-temperature liquid for calibration; The power source is a cryogenic pump or a compressor; The reversing valve group includes a sealing block, a connecting rod mechanism, a liquid guide hole, a sealing joint surface, a weighing tank, and an ejector pin; The sealing block is connected to the liquid diversion hole through the connecting rod mechanism, the weighing tank is arranged below the sealing block, the weighing tank is fixedly connected to the liquid diversion hole, the sealing joint surface is arranged between the sealing block and the weighing tank, the ejector pin is arranged below the weighing tank, the ejector pin and the sealing block are arranged opposite to each other, and the ejector pin and the connecting rod mechanism are on the same axis.

2. The ultra-low temperature liquid static mass method calibration device according to claim 1 is characterized in that: The outer shell of the cryogenic tank is made using vacuum.

3. A method for testing the static mass of ultra-low temperature liquids, characterized in that: The ultra-low temperature liquid static mass method verification method uses the ultra-low temperature liquid static mass method verification device according to claim 1 or 2, and the ultra-low temperature liquid static mass method verification method comprises: The third valve and the fifth valve are closed, the first valve, the second valve and the fourth valve are opened, the power source is started, and the liquid enters the cryogenic tank to cool the liquid. The liquid after entering the cryogenic tank enters the meter under test to ensure the low temperature state of the liquid and prevent the liquid from heating up and gasifying. The lifting mechanism in the reversing system falls, the reversing valve group is opened, and the liquid entering the weighing tank flows into the low temperature protection tank. When the liquid reaches the preset liquid level, the precooling of the meter under test is completed; Close the first valve, open the fifth valve, close the reversing system, lift the scale, and read the tare weight Q of the weighing tank after the scale reading stabilizes. ij ; The fifth valve is closed, the first valve is opened, the reversing system is opened, and after the flow rate is stabilized, the reversing system is closed, the cryogenic liquid is in the weighing tank, and the control system starts counting to measure the number of pulses output by the meter under test; When the number of pulses reaches a preset value, the first valve is closed, the fifth valve is opened, and the control system ends counting N. ij , read Q1 after the reading of the scale stabilizes ij ; Open the reversing system to drain the liquid in the weighing tank. If the liquid in the low-temperature protection tank is higher than the preset liquid level, close the fourth valve and open the third valve. When the liquid in the low-temperature protection tank drops to the preset liquid level, close the third valve and open the fourth valve to continue extracting liquid from the low-temperature storage tank. The fourth valve and the second valve are closed, and the third valve and the fifth valve are opened, so that the liquid flows from the low-temperature protection tank into the cryogenic tank, and returns to the cryogenic storage tank after being cooled in the cryogenic tank.

4. The ultra-low temperature liquid static mass method according to claim 3 is characterized in that: The cumulative mass measured by the ultra-low temperature liquid static mass method verification device is: Qs ij =Q1 ij -Q0 ij , the cumulative pulse number of the meter under test is: Q ij =N ij / K, the error calculation formula for a single calibration is as follows: Among them, Q ij Qs is the cumulative pulse number of the meter under test, ij It is the cumulative mass measured by the ultra-low temperature liquid static mass method calibration device.

5. The ultra-low temperature liquid static mass method verification method according to claim 3 is characterized in that: Also includes: When the lifting mechanism lifts the scale, the scale drives the weighing tank to be lifted, the sealing block is separated from the ejector pin, and under the action of the spring of the connecting rod mechanism, the sealing block moves downward, and the sealing block is combined with the sealing joint surface to play a sealing role; When the lifting mechanism is lowered, the weighing tank moves downward under the action of gravity, and the ejector pin pushes the sealing block to move upward, a gap is generated between the sealing joint surface and the sealing block, and the liquid flows out through the gap.

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