High-pressure adjustable active piston type gas flow standard device

Abstract

The utility model discloses a high-pressure adjustable active piston type gas flow standard device which comprises a gas supply assembly, a metering assembly and a test bed which are connected in sequence. The metering assembly comprises a first pipeline, a third valve, a horizontal cylindrical double-piston module and a fourth valve, a second pipeline is arranged beside the first pipeline, and a flow control assembly, a first valve and a second valve are arranged on the second pipeline. The horizontal column type double-piston module is provided with a balance cavity and a metering cavity, the balance cavity and the metering cavity are designed in a sealed mode, gas flows through the balance cavity and the metering cavity to be inflated, and the effect that the gas in the balance cavity and the gas in the metering cavity are constant in temperature and pressure is achieved. In addition, the balance cavity plays a role in balancing the pressure and the flow of the metering cavity in the verification and calibration process, so that the pressure and the flow of the metering cavity rapidly reach preset values, and the metering range of the metering cavity is fully utilized.

Description

Technical Field

[0001] The utility model relates to the field of gas flow standard devices, in particular to a high-pressure adjustable active piston type gas flow standard device. Background Art

[0002] The measurement methods used by gas flow standard devices mainly include bell method, piston method, soap film method, PVTt method, mass time (mt) method, sonic nozzle method and standard flow meter method. The piston type gas flow standard device is a new type of volume-time method gas flow standard device, which is developed from the bell type gas flow standard device and is used to calibrate gas flow meters with high pressure loss. At present, the piston type gas flow standard devices that have been put into use internationally are divided into active and passive types.

[0003] The passive piston gas flow standard device lacks a power drive device, and its piston can only move by the pressure between the fluid medium and the pipeline. It has a simple structure and low operating cost. Since the accuracy and response speed of the passive piston gas flow standard device are slightly inferior to those of the active device, most of the piston gas flow standard devices established internationally use active piston gas flow standard devices.

[0004] The active piston gas flow standard device pushes the piston to move through the drive unit. During the smooth movement of the piston, a stable and adjustable gas flow will continue to be generated, and finally the gas is discharged through the experimental pipeline and the flow meter under test. During the movement of the piston, the gas inside the piston cylinder has a slight fluctuation and then reaches a stable state. After reaching the stable state, it can be considered that the temperature and pressure of the gas inside the cylinder no longer change. The active piston gas flow standard device achieves precise control of the gas flow by actively adjusting the position of the piston. It has higher stability and accuracy, and is suitable for occasions with high requirements for flow changes.

[0005] The current active piston gas flow standard device has only one piston cylinder body, and a metering chamber is provided in the cylinder body. The volume of the metering chamber is changed by the movement of the piston rod, and the gas in the metering chamber is discharged to achieve precise control of the gas flow. When this active piston gas flow standard device is used to calibrate a flow meter (such as a flow meter) at normal pressure, there is no problem because the air pressure at both ends of the piston rod is at normal pressure. However, when calibrating a flow meter measuring high pressure (greater than 0.4MPa), the piston rod will be subjected to the reaction force of the gas in the metering chamber due to the inconsistent pressure at both ends of the piston rod. The reaction force will be applied to the drive unit, which will not only increase the output power of the drive unit and reduce its service life, but also cause the gas flow output from the metering chamber to be unstable, resulting in inaccurate calibration results. This is particularly obvious when calibrating flow meters with small flows (such as less than 1ml / min) and high pressures. Utility Model Content

[0006] The technical problem to be solved by the utility model is to provide a high-pressure adjustable active piston gas flow standard device, which is used to solve the problems of unstable flow and small pressure adjustment range of the current active piston gas flow standard device when calibrating high-pressure flow meters, and to realize the measurement verification and calibration of small flow meters under working pressure conditions.

[0007] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0008] A high-pressure adjustable active piston gas flow standard device comprises an air supply component, a metering component and a test bench connected in sequence; the metering component comprises a first pipeline connected between the air supply component and the test bench, a third valve, a horizontal cylindrical double-piston module and a fourth valve arranged on the first pipeline in sequence from the air supply component to the test bench, a second pipeline is arranged on one side of the first pipeline, a portion of the first pipeline between the fourth valve and the horizontal cylindrical double-piston module is connected to one end of the second pipeline, and the other end of the second pipeline is connected to the air supply component, a flow control component, a first valve and a second valve are arranged on the second pipeline in sequence from the air supply component to the first pipeline, a portion of the first pipeline between the third valve and the horizontal cylindrical double-piston module is connected to a portion of the second pipeline between the first valve and the second valve.

[0009] Furthermore, the horizontal cylindrical double-piston module includes a symmetrically arranged left cylinder and a right cylinder, the left cylinder and the right cylinder are coaxial, the openings of the left cylinder and the right cylinder are opposite, a guide column parallel to the axis of the left cylinder is provided between the left cylinder and the right cylinder, the left cylinder and the right cylinder are respectively fixedly connected to the corresponding end of the guide column, a T-shaped connecting block is slidably connected to the guide column, a piston rod is fixedly connected to the middle part of the T-shaped connecting block, two ends of the piston rod are respectively inserted into the left cylinder and the right cylinder, guide rings for guiding are provided between the piston rod and the left cylinder and between the piston rod and the right cylinder; the cavity on the left side of the piston rod in the left cylinder is a balancing chamber connected to the third valve, the cavity on the right side of the piston rod in the right cylinder is a metering chamber connected to the fourth valve, a differential pressure gauge is connected between the metering chamber and the balancing chamber; the T-shaped connecting block is provided with a driving unit for driving it to move axially along the piston rod.

[0010] Furthermore, the driving unit includes a screw rod threadedly connected to the T-shaped connecting block, the screw rod is a ball screw, the ball screw is parallel to the piston rod, one end of the ball screw is provided with a servo motor for driving the rotation thereof, and the servo motor is in turn connected to the ball screw through a reducer and a coupling.

[0011] Furthermore, a grating ruler for measuring the displacement of the T-shaped connecting block is provided next to the left cylinder.

[0012] Furthermore, the test bench is a sonic nozzle detection test bench and / or a flow meter detection test bench.

[0013] Furthermore, the sonic nozzle detection test bench includes a fourth pipe connected to the end of the first pipe away from the air supply component, and the fourth pipe is connected with a seventh valve, a stagnation container, a first fixture, a back pressure container and a ninth valve in sequence from near to far at the end close to the first pipe. The ninth valve is connected to the outside atmosphere, and the sonic nozzle to be tested is installed on the first fixture.

[0014] Furthermore, the portion of the fourth pipeline between the back pressure container and the ninth valve is sequentially connected to the eighth valve and the vacuum pump.

[0015] Furthermore, the flow meter test bench includes a third pipe connected to the end of the first pipe away from the air supply component, and the third pipe is connected with a fifth valve, a second fixture, a sixth valve and a back pressure regulating valve group in sequence from near to far at the end close to the first pipe. The flow meter to be measured is installed on the second fixture, and the back pressure regulating valve group is connected to the outside atmosphere.

[0016] Furthermore, a pressure sensor and a temperature sensor are provided in sequence at a portion of the third pipeline between the fifth valve and the second fixture.

[0017] Furthermore, the metering component is provided with at least one group, the gas supply component includes an air distribution pipe, the air distribution pipe is connected with a tenth valve and an air source pretreatment unit in parallel, the air source pretreatment unit includes a pressure reducing valve, a heat exchanger, a gas storage tank group 3600L, a switch valve, a high-pressure dehumidifier, a degassing tank group 1000L and an air compressor connected in sequence to the air distribution pipe, and a humidity sensor is also provided on the air distribution pipe.

[0018] The positive effects of the utility model are:

[0019] 1. The utility model is provided with a gas supply component, a metering component and a test bench. The metering component includes a horizontal columnar double piston module. The horizontal columnar double piston module is provided with two chambers, a balancing chamber and a metering chamber. The balancing chamber and the metering chamber are sealed. The gas flows through the balancing chamber and the metering chamber for inflation, and plays a role in keeping the gas in the balancing chamber and the metering chamber at a constant temperature and pressure. In addition, the balancing chamber also plays a role in balancing the pressure and flow of the metering chamber during the verification and calibration process, so that the pressure and flow of the metering chamber quickly reach the preset value, so that the metering range of the metering chamber is fully utilized.

[0020] 2. The two ends of the piston rod correspond to the balance chamber and the metering chamber respectively. The pressure in the balance chamber and the metering chamber is balanced, so that both ends of the piston rod are stressed and the force acting on the piston rod is balanced, thereby reducing the stress on the servo motor and extending the service life of the horizontal column type double piston module. At the same time, the servo motor outputs a very small torque to achieve stable movement of the piston rod, so that the utility model has a more stable flow rate and a large pressure adjustment range when calibrating high-pressure flow meters. 3. The test bench includes a sonic nozzle test bench and a flow meter test bench. The flow meter under test can be calibrated using the constant current method and the constant pressure method, and the sonic nozzle can be calibrated using the positive pressure method or the negative pressure method. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the system principle diagram of the utility model;

[0022] Figure 2 It is a structural schematic diagram of a horizontal cylindrical double piston module;

[0023] Figure 3 It is the system schematic diagram of the metering component;

[0024] Figure 4 It is the system schematic diagram of the gas source pretreatment unit;

[0025] In the figure: 1-1, air compressor; 1-2, gas tank 1000L; 1-3, high-pressure dehumidifier; 1-4, switch valve; 1-5, gas tank group 3600L; 1-6, heat exchanger; 1-7, pressure reducing valve; 1-8, vacuum pump; 2-1, servo motor; 2-2, reducer; 2-3, coupling; 2-4, ball screw; 2-5, T-type connection block; 2-6, guide column; 2-7, balance chamber; 2-8, left cylinder; 2-9, piston rod; 2-10, guide ring; 2-11, right cylinder; 2-12, metering chamber; 2-13, horizontal column type double piston module; 3-1, precision pressure regulating valve group; 3-2, flow controller group; 3-3, stagnation container; 3-4, back pressure container; 3-5, back pressure regulating valve group; 4-1. Grating ruler; 4-2. Temperature sensor; 4-3. Pressure sensor; 4-4. Humidity sensor; 5. Sonic nozzle to be measured; 6. Flow meter to be measured; 7. Sonic nozzle detection test bench; 8. Flow meter detection test bench; 9. First pipeline; 10. Second pipeline; 11. First valve; 12. Second valve; 13. Third valve; 14. Fourth valve; 15. Third pipeline; 16. Fifth valve; 17. Sixth valve; 18. Fourth pipeline; 19. Seventh valve; 20. Eighth valve; 21. Ninth valve; 22. Gas distribution pipe; 23. Tenth valve. DETAILED DESCRIPTION

[0026] like Figure 1 and Figure 3 As shown, a high-pressure adjustable active piston type gas flow standard device includes a gas supply component, a metering component 2 and a test bench connected in sequence from left to right. The metering component 2 includes a first pipeline 9 connected between the gas supply component and the test bench, a third valve 13, a horizontal cylindrical double piston module 2-13 and a fourth valve 14 arranged in sequence on the first pipeline 9 from left to right, a second pipeline 10 is arranged beside the first pipeline 9, the first pipeline 9 is located between the fourth valve 14 and the horizontal cylindrical double piston module 2-13 and is connected to one end of the second pipeline 10, and the other end of the second pipeline 10 is connected to the gas supply component, and the second pipeline 10 is sequentially provided with a flow control component 3-2, a first valve 11 and a second valve 12 from the gas supply component to the first pipeline 9, and the first pipeline 9 is located between the third valve 13 and the horizontal cylindrical double piston module 2-13. The part of the second pipeline 10 located between the first valve 11 and the second valve 12 is connected to the part of the second pipeline 10 located between the first valve 11 and the second valve 12.

[0027] Combination Figure 2 As shown, the horizontal cylindrical double-piston module 2-13 includes a symmetrically arranged left cylinder 2-8 and a right cylinder 2-11, the left cylinder 2-8 and the right cylinder 2-11 are coaxial, the openings of the left cylinder 2-8 and the right cylinder 2-11 are opposite, and a guide column 2-6 parallel to the axis of the left cylinder 2-8 is provided between the left cylinder 2-8 and the right cylinder 2-11, and the guide column 2-6 is two upper and lower arranged outer circles of the left cylinder 2-8 and the right cylinder 2-11 are respectively fixedly connected to the corresponding end of the guide column 2-6, A T-type connection block 2-5 is slidably connected to the guide column 2-6, and a piston rod 2-9 is fixedly connected to the middle of the T-type connection block 2-5. The two ends of the piston rod 2-9 are respectively inserted into the left cylinder 2-8 and the right cylinder 2-11. A guide ring 2-10 for guiding the piston rod 2-9 is provided between the piston rod 2-9 and the left cylinder 2-8, and between the piston rod 2-9 and the right cylinder 2-11. A grating ruler 4-1 for measuring the displacement of the T-type connection block 2-5 is provided next to the left cylinder 2-8. The grating ruler 4-1 serves as a feedback carrier for the movement distance of the horizontal column type double piston module 2-13, and transmits the feedback signal to the computer control system. The grating ruler 4-1 is a feedback device for measuring displacement that works based on the optical principle of the grating. Its structure and working principle are both existing technologies and will not be repeated here.

[0028] The cavity on the left side of the piston rod 2-9 in the left cylinder 2-8 is a balancing cavity 2-7 connected to the third valve 13, and the cavity on the right side of the piston rod 2-9 in the right cylinder 2-11 is a metering cavity 2-12 connected to the fourth valve 14. A differential pressure gauge is connected between the metering cavity 2-12 and the balancing cavity 2-7. A driving unit for driving the T-shaped connecting block 2-5 to move axially along the piston rod 2-9 is provided.

[0029] The driving unit includes a screw rod that is threadedly connected to the top of the T-shaped connecting block 2-5, and the screw rod is a ball screw rod 2-4. The ball screw rod 2-4 is parallel to the piston rod 2-9. The left end of the ball screw rod 2-4 is provided with a servo motor 2-1 for driving it to rotate. The servo motor 2-1 is in turn connected to the ball screw rod 2-4 through a reducer 2-2 and a coupling 2-3.

[0030] The metering components 2 are arranged in three groups side by side, and the horizontal cylindrical double piston modules 2-13 of the three groups of metering components 2 are respectively 0.02L horizontal cylindrical double piston modules, 0.2L horizontal cylindrical double piston modules and 3L horizontal cylindrical double piston modules. The air supply component includes an air distribution pipe 22. The left ends of the first pipelines 9 of the three groups of metering components are all connected to the air distribution pipe 22, and the left ends of the three groups of second pipelines 10 are connected to the flow control valve group 3-2 after being connected. The left end of the flow control valve group 3-2 is connected to the air distribution pipe 22, and the air distribution pipe 22 is also connected to a humidity sensor 4-4. The gas supply assembly also includes a tenth valve 23 and an air source pretreatment unit connected to the gas distribution pipe 22. The gas source pretreatment unit includes a pressure reducing valve 1-7, a heat exchanger 1-6, a gas storage tank group 3600L1-5, a switch valve 1-4, a high-pressure dehumidifier 1-3, a degassing tank group 1000L1-2 and an air compressor 1-1 connected from right to left. The right end of the pressure reducing valve 1-7 is connected to the gas distribution pipe 22 through a precision pressure regulating valve group 3-1. A humidity sensor 4-4 is also provided on the gas distribution pipe 22.

[0031] The test benches are a sonic nozzle test bench 7 and a flow meter test bench 8 which are connected side by side to the right ends of the first pipelines 9 of the three metering components 2 .

[0032] The sonic nozzle test bench 7 includes a fourth pipe 18 connected to the right end of the first pipe 9, and the seventh valve 19, the stagnation container 3-3, the first fixture, the back pressure container 3-4 and the ninth valve 21 are connected to the fourth pipe 18 from left to right in sequence, and the right end of the ninth valve 21 is connected to the outside atmosphere through a muffler, and the sonic nozzle 5 to be tested is installed on the first fixture. The portion of the fourth pipe 18 between the back pressure container 3-4 and the ninth valve 21 is connected to the eighth valve 20 and the vacuum pump 1-8 in sequence.

[0033] The flow meter test bench 8 includes a third pipe 15 connected to the right end of the first pipe 9, and the third pipe 15 is connected with a fifth valve 16, a second fixture, a sixth valve 17 and a back pressure regulating valve group 3-5 from left to right in sequence. The measured flow meter 6 is installed on the second fixture, and the right end of the back pressure regulating valve group 3-5 is connected to the outside atmosphere.

[0034] The portion of the third pipeline 15 between the fifth valve 16 and the second fixture is provided with a pressure sensor 4 - 3 and a temperature sensor 4 - 2 in sequence from left to right.

[0035] The method of using the utility model is:

[0036] 1. Use the flow meter test bench 8 to verify and calibrate the flow meter 6 to be tested. When using the constant pressure working mode, the horizontal column type double piston module 2-13 uses a 0.02L horizontal column type double piston module as a calibrator. The specific working process is as follows:

[0037] (1) Adjust the precision pressure regulating valve group 3-1, open the third valve 13, the second valve 12 and the fourth valve 14 corresponding to the 0.02L horizontal column type double piston module, open the fifth valve 16, and close the first valve 11 corresponding to the 0.02L horizontal column type double piston module. Close the seventh valve 19 of the sonic nozzle test bench 7, and supply air to the 0.02L horizontal column type double piston module and the measured flow meter 6. Set the target flow of the measured flow meter 6, and adjust the needle regulating valve in the back pressure regulating valve group 3-5 so that the pressure in the first pipeline 9 reaches the required working pressure (generally more than 100 kPa), so that the measured flow meter 6 is in the pre-operation state.

[0038] (2) Start the servo motor 2-1. The servo motor 2-1 drives the ball screw 2-4 to rotate at a stable speed. The ball screw 2-4 drives the piston rod 2-9 to move to the left, so that the piston rod 2-9 is reset to the left part of the left cylinder 2-8.

[0039] (3) The speed of the servo motor 2-1 is initially set according to the target flow value of the measured flow meter 6. The servo motor 2-1 drives the ball screw 2-4 to rotate at a stable speed. The ball screw 2-4 drives the piston rod 2-9 to move to the right. The reading head of the grating ruler 4-1 moves synchronously with the piston rod 2-9. The piston rod 2-9 moves to the right and enters the right cylinder 2-11, while withdrawing from the left cylinder 2-8. When the balance chamber 2-7 and the metering chamber 2-12 reach flow balance, close the second valve 12, start the 0.02L horizontal column type double piston module PID adjustment, fine-tune the flow output by the piston 2-13, so that the pressure in the metering chamber 2-12 remains balanced, and start the verification and calibration work.

[0040] (4) The computer control system records in real time the temperature, pressure, humidity of the 0.02L horizontal columnar double piston module and the measured flow meter 6, the displacement signal of the grating ruler 4-1, and the movement time of the piston rod 2-9.

[0041] (5) After the verification and calibration work is completed, control the servo motor 2-1 to rotate in the reverse direction until the piston rod 2-9 returns to the left part of the left cylinder 2-8, and then repeat the above steps (1) to (4).

[0042] 2. Use the flow meter test bench 8 to verify and calibrate the flow meter 6 to be tested. When the constant flow working mode is adopted, the horizontal column type double piston module 2-13 uses a 0.02L horizontal column type double piston module as a calibrator. The specific working process is as follows:

[0043] (1) Adjust the precision pressure regulating valve group 3-1, preliminarily set the target flow of the flow controller group 3-2 according to the target flow value of the measured flow meter 6, open the fifth valve 16 and the first valve 11, the second valve 12 and the fourth valve 14 pneumatic valves corresponding to the 0.02L horizontal column type double piston module, and close the third valve 13 corresponding to the 0.02L horizontal column type double piston module. Close the seventh valve 19 of the sonic nozzle test bench 7, and according to the pressure requirement of the measured flow meter 6, open the sixth valve 17 or the eleventh valve 24 on the third pipeline 15 connected between the measured flow meter 6 and the sixth valve 17. If the valve 24 is opened, the needle regulating valve or the flow regulating valve in the back pressure regulating valve group 3-5 needs to be fine-tuned to make the measured flow meter 6 in the pre-operation state at the target flow.

[0044] (2) Start the servo motor 2-1. The servo motor 2-1 drives the ball screw 2-4 to rotate at a stable speed. The ball screw 2-4 drives the piston rod 2-9 to move to the left, so that the piston rod 2-9 is reset to the left part of the left cylinder 2-8.

[0045] (3) The speed of the servo motor 2-1 is initially set according to the target flow value of the measured flow meter 6. The servo motor 2-1 drives the ball screw 2-4 to rotate at a stable speed. The ball screw 2-4 drives the piston rod 2-9 to move to the right. The reading head of the grating ruler 4-1 moves synchronously with the piston rod 2-9. The piston rod 2-9 moves to the right and enters the right cylinder 2-11, while withdrawing from the left cylinder 2-8. When the balance chamber 2-7 and the metering chamber 2-12 reach flow balance, the second valve 12 is closed, and the PID adjustment of the 0.02L horizontal column type double piston module is started. After the flow output of the 0.02L horizontal column type double piston module is balanced with the target flow of the flow controller group 3-2, the verification and calibration of the measured flow meter 6 is started.

[0046] (4) The computer control system records in real time the temperature, pressure, humidity of the 0.02L horizontal columnar double piston module and the measured flow meter 6, the displacement signal of the grating ruler 4-1, and the movement time of the piston rod 2-9.

[0047] (5) After the verification and calibration work is completed, control the servo motor 2-1 to rotate in the opposite direction until the piston rod 2-9 returns to the head of the left cylinder 2-8, and then repeat the above steps (1) to (4).

[0048] 3. Use the sonic nozzle test bench 7 to verify and calibrate the sonic nozzle 5 under test. The horizontal column type double piston module 2-13 selected is a 0.02L horizontal column type double piston module, which is used as a calibrator. The specific process of using the positive pressure method is as follows:

[0049] (1) The air supply assembly provides compressed air, closes the eighth valve 20, the first valve 11, and the fifth valve 16, opens the third valve 13, the second valve 12, the fourth valve 14, and the seventh valve 19, and adjusts the precision pressure regulating valve group 3-1 so that the sonic nozzle 5 under test reaches the critical back pressure ratio.

[0050] (2) Start the servo motor 2-1. The servo motor 2-1 drives the ball screw 2-4 to rotate at a stable speed. The ball screw 2-4 drives the piston rod 2-9 to move to the left, so that the piston rod 2-9 is reset to the left part of the left cylinder 2-8.

[0051] (3) The speed of the servo motor 2-1 is initially set according to the target flow value of the sonic nozzle 5 to be measured. The servo motor 2-1 drives the ball screw 2-4 to rotate at a stable speed. The ball screw 2-4 drives the piston rod 2-9 to move to the right. The reading head of the grating ruler 4-1 moves synchronously with the piston rod 2-9. The piston rod 2-9 moves to the right and enters the right cylinder 2-11, while withdrawing from the left cylinder 2-8. When the balance chamber 2-7 and the metering chamber 2-12 reach flow balance, close the second valve 12, start the PID adjustment of the 0.02L horizontal column type double piston module, fine-tune the flow output by the 0.02L horizontal column type double piston module, keep the pressure in the metering chamber 2-12 balanced, and start the verification and calibration work.

[0052] (4) The computer control system records in real time the temperature, pressure, humidity of the 0.02L horizontal columnar double piston module and the sonic nozzle 5 under test, the displacement signal of the grating ruler 4-1, and the movement time of the piston rod 2-9.

[0053] (5) After the verification and calibration work is completed, control the servo motor 2-1 to rotate in the reverse direction until the piston rod 2-9 returns to the left part of the left cylinder 2-8, and then repeat the above steps (1) to (4).

[0054] 4. Use the sonic nozzle test bench 7 to verify and calibrate the sonic nozzle 5 under test. The horizontal column type double piston module 2-13 selected is a 0.02L horizontal column type double piston module, which is used as a calibrator. The specific working process of the negative pressure method is as follows:

[0055] (1) Close all valves on the air supply assembly, open the seventh valve 23, the third valve 13, the fourth valve 14, the second valve 12, the seventh valve 19 and the eighth valve 20, close the first valve 11 and the ninth valve 21, start the vacuum pump 1-8, reduce the downstream pressure of the 0.02L horizontal column type double piston module, and make the back pressure of the measured sonic nozzle 5 reach the critical back pressure ratio.

[0056] (2) Start the servo motor 2-1. The servo motor 2-1 drives the ball screw 2-4 to rotate at a stable speed. The ball screw 2-4 drives the piston rod 2-9 to move to the left, so that the piston rod 2-9 is reset to the left part of the left cylinder 2-8.

[0057] (3) The speed of the servo motor 2-1 is initially set according to the target flow value of the sonic nozzle 5 to be measured. The servo motor 2-1 drives the ball screw 2-4 to rotate at a stable speed. The ball screw 2-4 drives the piston rod 2-9 to move to the right. The reading head of the grating ruler 4-1 moves synchronously with the piston rod 2-9. The piston rod 2-9 moves to the right and enters the right cylinder 2-11, while withdrawing from the left cylinder 2-8. When the balance chamber 2-7 and the metering chamber 2-12 of the piston reach flow balance, the pneumatic valve 7 is closed, the piston device PID adjustment is started, and the flow output by the piston 2-13 is fine-tuned to keep the pressure in the metering chamber 2-12 balanced, and the verification and calibration work is started.

[0058] (4) The computer control system records in real time the temperature, pressure, humidity of the 0.02L horizontal columnar double piston module and the sonic nozzle 5 under test, the displacement signal of the grating ruler 4-1, and the piston movement time.

[0059] (5) After the verification and calibration work is completed, control the servo motor 2-1 to rotate in the opposite direction until the piston returns to the head of the left cylinder 2-8, and then repeat the above steps (1) to (4).

[0060] The operating flow range of 0.02L horizontal column type dual piston module is (0.1~20)mL / min, the operating flow range of 0.2L horizontal column type dual piston module is (0.8~200)mL / min, and the operating flow range of 3L horizontal column type dual piston module is (0.01~3)L / min. It can verify or calibrate the measured flow meter 6 of small flow gas.

[0061] The horizontal column type double piston module 2-13 is provided with two chambers, the balancing chamber 2-7 and the metering chamber 2-12. The balancing chamber 2-7 is designed to be sealed. The gas flows through the balancing chamber 2-7 and the metering chamber 2-12 for inflation, and plays the role of keeping the gas in the balancing chamber 2-7 and the metering chamber 2-12 at a constant temperature and pressure. In addition, the balancing chamber 2-7 also plays the role of balancing the pressure and flow of the metering chamber 2-12 during the verification and calibration process, so that the pressure and flow of the metering chamber 2-12 quickly reach the preset value, so that the metering range of the metering chamber 2-12 is fully utilized.

[0062] The two ends of the piston rod 2-9 correspond to the balance chamber 2-7 and the metering chamber 2-12 respectively. The pressure in the balance chamber 2-7 and the metering chamber 2-12 is balanced, so that both ends of the piston rod 2-9 are stressed and the force acting on the piston rod 2-9 is balanced, thereby reducing the stress on the servo motor 2-1 and extending the service life of the horizontal column type double piston module 2-13. At the same time, the servo motor 2-1 outputs a very small torque to achieve stable movement of the piston rod 2-9, so that the utility model has a more stable flow rate and a large pressure adjustment range when calibrating high-pressure flow meters.

[0063] The above-mentioned embodiments describe content in a relatively detailed and specific manner, and express the preferred embodiments of the present utility model. They are only used to illustrate the technical ideas and features of the present utility model, and their purpose is to enable technicians in this field to understand the content of the present utility model and implement it accordingly, but they are not limited to the present utility model. The patent scope of the present utility model cannot be limited only by this embodiment, that is, any equivalent changes or modifications made to the spirit disclosed by the present utility model, for researchers or technicians in this field, without departing from the structure of the present utility model, local improvements within the system and changes and conversions between subsystems, etc., are still within the patent scope of the present utility model.

Claims

1. A high-pressure adjustable active piston type gas flow standard device, characterized in that: The invention comprises an air supply component, a metering component (2) and a test bench connected in sequence; the metering component (2) comprises a first pipeline (9) connected between the air supply component and the test bench, a third valve (13), a horizontal cylindrical double piston module (2-13) and a fourth valve (14) arranged in sequence on the first pipeline (9) from the air supply component to the test bench, a second pipeline (10) is arranged on one side of the first pipeline (9), a portion of the first pipeline (9) between the fourth valve (14) and the horizontal cylindrical double piston module (2-13) is connected to one end of the second pipeline (10), and the other end of the second pipeline (10) is connected to the air supply component; a flow control component (3-2), a first valve (11) and a second valve (12) are arranged in sequence on the second pipeline (10) from the air supply component to the first pipeline (9), and a portion of the first pipeline (9) between the third valve (13) and the horizontal cylindrical double piston module (2-13) is connected to a portion of the second pipeline (10) between the first valve (11) and the second valve (12).

2. A high-pressure adjustable active piston type gas flow standard device according to claim 1, characterized in that: The horizontal columnar double piston module (2-13) comprises a symmetrically arranged left cylinder (2-8) and a right cylinder (2-11), the left cylinder (2-8) and the right cylinder (2-11) being coaxial, the openings of the left cylinder (2-8) and the right cylinder (2-11) being opposite, a guide column (2-6) being arranged between the left cylinder (2-8) and the right cylinder (2-11) and being parallel to the axis of the left cylinder (2-8), the left cylinder (2-8) and the right cylinder (2-11) being respectively fixedly connected to one end corresponding to the guide column (2-6), a T-shaped connecting block (2-5) being slidably connected to the guide column (2-6), a piston rod (2-9) being fixedly connected to the middle of the T-shaped connecting block (2-5), and both ends of the piston rod (2-9) being respectively inserted into Into the left cylinder (2-8) and the right cylinder (2-11), a guide ring (2-10) for guiding is provided between the piston rod (2-9) and the left cylinder (2-8) and between the piston rod (2-9) and the right cylinder (2-11); the cavity located on the left side of the piston rod (2-9) in the left cylinder (2-8) is a balancing cavity (2-7) connected to the third valve (13), and the cavity located on the right side of the piston rod (2-9) in the right cylinder (2-11) is a metering cavity (2-12) connected to the fourth valve (14), and a differential pressure gauge is connected between the metering cavity (2-12) and the balancing cavity (2-7); and the T-shaped connecting block (2-5) is provided with a driving unit for driving it to move axially along the piston rod (2-9).

3. A high-pressure adjustable active piston type gas flow standard device according to claim 2, characterized in that: The drive unit comprises a screw connected to a T-shaped connection block (2-5) through a thread, the screw being a ball screw (2-4), the ball screw (2-4) being parallel to a piston rod (2-9), one end of the ball screw (2-4) being provided with a servo motor (2-1) for driving the ball screw (2-4) to rotate, the servo motor (2-1) being sequentially connected to the ball screw (2-4) through a reducer (2-2) and a coupling (2-3).

4. A high-pressure adjustable active piston type gas flow standard device according to claim 2, characterized in that: A grating ruler (4-1) for measuring the displacement of the T-shaped connecting block (2-5) is provided on one side of the left cylinder (2-8).

5. A high-pressure adjustable active piston type gas flow standard device according to claim 1, characterized in that: The test bench is a sonic nozzle detection test bench (7) and / or a flow meter detection test bench (8).

6. A high-pressure adjustable active piston type gas flow standard device according to claim 5, characterized in that: The sonic nozzle detection test bench (7) comprises a fourth pipe (18) connected to an end of the first pipe (9) away from the air supply assembly, the fourth pipe (18) being connected in sequence from the end close to the first pipe (9) to a seventh valve (19), a stagnation container (3-3), a first fixture, a back pressure container (3-4) and a ninth valve (21), the ninth valve (21) being connected to the outside atmosphere, and the sonic nozzle (5) to be tested is mounted on the first fixture.

7. A high-pressure adjustable active piston type gas flow standard device according to claim 6, characterized in that: The portion of the fourth pipeline (18) located between the back pressure container (3-4) and the ninth valve (21) is connected in sequence to the eighth valve (20) and the vacuum pump (1-8).

8. A high-pressure adjustable active piston type gas flow standard device according to claim 5, characterized in that: The flow meter test bench (8) comprises a third pipe (15) connected to an end of the first pipe (9) away from the air supply component, and the third pipe (15) is connected with a fifth valve (16), a second fixture, a sixth valve (17) and a back pressure regulating valve group (3-5) in sequence from the end close to the first pipe (9) to the farthest end, the flow meter (6) to be measured is installed on the second fixture, and the back pressure regulating valve group (3-5) is connected to the outside atmosphere.

9. A high-pressure adjustable active piston type gas flow standard device according to claim 8, characterized in that: A pressure sensor (4-3) and a temperature sensor (4-2) are provided in sequence at a portion of the third pipeline (15) located between the fifth valve (16) and the second clamp.

10. A high-pressure adjustable active piston type gas flow standard device according to claim 1, characterized in that: The metering component is provided with at least one group, the gas supply component comprises a gas distribution pipe (22), the gas distribution pipe (22) is connected in parallel with a tenth valve (23) and a gas source pretreatment unit, the gas source pretreatment unit comprises a pressure reducing valve (1-7), a heat exchanger (1-6), a gas storage tank group 3600L (1-5), a switch valve (1-4), a high-pressure dehumidifier (1-3), a degassing tank group 1000L (1-2) and an air compressor (1-1) connected in sequence to the gas distribution pipe (22), and a humidity sensor (4-4) is also provided on the gas distribution pipe (22).

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