High-pressure adjustable driving disc piston type gas flow standard device

Abstract

The utility model relates to a high-pressure adjustable driving disc piston type gas flow standard device, which structurally comprises a manifold, the manifold is communicated with the atmosphere through an air inlet valve, and the manifold is communicated with a gas source pretreatment module through a pressure adjusting module; the manifold is connected with one or more disc-type piston devices connected in parallel through an upstream pipeline, each disc-type piston device comprises a sealed piston cylinder, each piston cylinder is divided into a balance cavity and a metering cavity by a disc-type piston, the balance cavities are communicated with the metering cavities through connecting pipelines, and differential pressure sensors are arranged between the balance cavities and the metering cavities; the balance cavity is communicated with the upstream pipeline, the metering cavity is connected with the detection test bench through the downstream pipeline, and the piston rod is connected with the driving mechanism. According to the utility model, the gas in the metering cavity can quickly reach a stable state, so that the pressure and the flow of the metering cavity can quickly reach preset values, the volume of the metering cavity is fully utilized, and metrological verification and calibration of medium and small flow instruments under the working pressure condition are realized.

Description

Technical Field

[0001] The utility model relates to a gas flow standard device, in particular to a high-pressure adjustable active disc type 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 can be 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 device lacks a power drive device, and the piston can only move by relying on 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 are slightly inferior to those of the active device, most of the piston-type gas flow standard devices established internationally are active. The active piston device drives the piston to move through the driving device. 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 being tested. The active piston 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.

[0004] One side of the existing active piston device is a metering chamber connected to the device under test, and the other side is connected to the atmosphere. When the pressure required by the device under test is relatively small, due to the low gas pressure inside the metering chamber, the resistance encountered by the driving mechanism when driving the piston to move is relatively small. During the movement of the piston, the gas inside the piston cylinder has a slight fluctuation and then can quickly reach 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. However, under higher pressure conditions, when performing verification and calibration work, the pressure of the gas in the metering chamber is relatively large, resulting in a large pressure difference on both sides of the piston. During the piston movement of the existing active piston device, the resistance encountered by the driving mechanism when driving the piston to move is relatively large, and the gas inside the metering chamber will produce large fluctuations. It takes a long time to reach a stable state, which affects the stability and accuracy of the gas flow standard device, and cannot fully utilize the volume of the metering chamber. At the same time, the pressure adjustment range of the existing active piston gas flow standard device is small, and it cannot meet the needs of verification or calibration of small and medium flow gas flow meters with high pressure loss. Utility Model Content

[0005] The utility model aims to provide a high-pressure adjustable active disc piston type gas flow standard device to solve the problems of unstable flow, inability to fully utilize the volume of the metering chamber, pressure adjustment range, etc. of the existing active piston type gas flow standard device.

[0006] The utility model is implemented as follows: a high-pressure adjustable active disc-type piston type gas flow standard device, comprising a manifold, the manifold is connected to the atmosphere through an intake valve, and the manifold is connected to a gas source pretreatment module through a pressure regulating module; the manifold is connected to one or more disc-type piston devices in parallel through an upstream pipeline, and the disc-type piston device is connected to a detection test bench through a downstream pipeline; the disc-type piston device comprises a piston cylinder, a disc-type piston is arranged in the piston cylinder, the piston cylinder is a sealed cavity, the disc-type piston divides the piston cylinder into a balancing chamber and a metering chamber, a pressure difference sensor is arranged between the balancing chamber and the metering chamber, wherein the upstream pipeline is connected to the balancing chamber, the downstream pipeline is connected to the metering chamber, and the balancing chamber and the metering chamber are connected through a connecting pipeline, valves are arranged on each pipeline, the piston is connected to a piston rod, the piston rod passes through the balancing chamber and extends out of the piston cylinder to be connected to a driving mechanism.

[0007] As a further improvement of the high-pressure adjustable active disc type piston gas flow standard device of the utility model, the driving mechanism includes a servo motor, a reducer, a coupling and a screw rod. The outer end of the piston rod is connected to the guide column through a guide plate, and a grating scale is arranged on one side of the guide column.

[0008] As a further improvement of the high-pressure adjustable active disc-type piston gas flow standard device of the utility model, there are two disc-type piston devices, and the working flow ranges of the two disc-type piston devices are (0.1~30)L / min and (1~500)L / min respectively.

[0009] As a further improvement of the high-pressure adjustable active disc-type piston-type gas flow standard device of the utility model, the gas source pretreatment module includes an air compressor, a buffer container, a high-pressure dehumidifier, a switch valve, a gas storage container, a heat exchanger and a pressure reducing valve connected in sequence.

[0010] As a further improvement of the high-pressure adjustable active disc-type piston-type gas flow standard device of the utility model, the pressure regulating module includes a first pressure regulating pipeline and a second pressure regulating pipeline connected in parallel, a pressure reducing valve and a switch valve are arranged in sequence on the first pressure regulating pipeline, and two pressure reducing valves and a switch valve are arranged in sequence on the second pressure regulating pipeline.

[0011] As a further improvement of the high-pressure adjustable active disc-type piston gas flow standard device of the utility model, the upstream pipeline includes a constant flow pipeline and a constant pressure pipeline in parallel, a flow controller group and a switch valve are arranged on the constant flow pipeline, and a switch valve is arranged on the constant pressure pipeline.

[0012] As a further improvement of the high-pressure adjustable active disc type piston type gas flow standard device of the utility model, the detection test bench includes a sonic nozzle detection test bench and a flow meter type detection test bench.

[0013] Among them, the sonic nozzle detection test bench includes a first detection pipeline, on which a stagnation container, a nozzle installation station, and a back pressure container are arranged in sequence. The end of the first detection pipeline is connected to the atmosphere and is connected in parallel with a vacuum pump.

[0014] The flow meter test bench includes a second test pipeline, on which a flow meter installation station is arranged, and at the end of the second test pipeline, a back pressure regulating valve group is connected and a branch connected to the atmosphere is connected in parallel.

[0015] The utility model discloses a high-pressure adjustable active disc-type piston gas flow standard device. The piston gas flow standard device adopts an active type. During the stable movement of the piston, a stable and adjustable gas flow will be continuously generated. The disc-type piston device is driven by a driving mechanism to move the piston. The disc-type piston divides the inner cavity of the piston cylinder into a balancing cavity and a metering cavity. The balancing cavity has a pressure compensation function, which can make the pressure and flow of the balancing cavity and the metering cavity quickly reach a dynamic balance, so that the gas pressure difference on both sides of the piston disc is very small and tends to be balanced, reducing the output torque of the driving mechanism, shortening the time for the gas flow in the metering cavity to reach a stable state, making the pressure and flow of the metering cavity quickly reach a preset value, making the volume of the metering cavity fully utilized, and at the same time playing a role of constant temperature and constant pressure on the gas flowing through the balancing cavity, thereby improving the stability and accuracy of the gas flow standard device detection.

[0016] The manifold is provided with a high-pressure gas source by the gas source pretreatment module, and the gas source pressure is adjusted by the pressure regulating module, so that the utility model is suitable for different gas pressure requirements during detection. The upstream pipeline is divided into a constant pressure pipeline and a constant flow pipeline, which can provide constant pressure airflow and constant flow airflow respectively, and can meet the needs of different constant flow and constant pressure modes. Multiple active disc-type piston devices can be set in parallel to provide different working flow ranges, which can meet the detection of different flow conditions.

[0017] The test bench includes a sonic nozzle test bench and a flow meter test bench, which can be used for the detection of sonic nozzles and flow meters respectively. The detection pipeline of the sonic nozzle test bench is connected to the atmosphere or a vacuum pump, and with the valve on the manifold directly connected to the atmosphere, the sonic nozzle can be tested by both positive pressure and negative pressure methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural diagram of the utility model.

[0019] Figure 2 It is a structural diagram of the disc-type piston device of the utility model.

[0020] Figure 3 It is a structural diagram of the gas source pretreatment module of the utility model.

[0021] In the figure: 1, manifold; 2, gas source processing module; 3, pressure regulating module; 4, first disc-type piston device; 5, second disc-type piston device; 6, sonic nozzle detection test bench; 7, flow meter detection test bench; 8, constant flow pipeline; 9, first constant pressure pipeline; 10, second constant pressure pipeline; 11, first connecting pipeline; 12, second connecting pipeline; 13, third connecting pipeline; 14, fourth connecting pipeline; 15, flow controller group; 16, second heat exchanger; 17, fourth switch valve; 18, fifth switch valve; 19, sixth switch valve; 20, seventh switch valve; 21, eighth switch valve; 22, ninth switch valve; 23, tenth switch valve; 24, eleventh switch valve; 25, twelfth switch valve; 26, thirteenth switch valve; 27, sonic nozzle under test; 28, flow meter under test;

[0022] 1-1, Intake valve;

[0023] 2-1, air compressor; 2-2, buffer container; 2-3, high-pressure dehumidifier; 2-4, first switch valve; 2-5, gas storage container; 2-6, first heat exchanger; 2-7, fourth pressure reducing valve;

[0024] 3-1, first pressure regulating pipeline; 3-2, second pressure regulating pipeline; 3-3, first pressure reducing valve; 3-4, second switch valve; 3-5, second pressure reducing valve; 3-6, third pressure reducing valve; 3-7, third switch valve;

[0025] 4-1, piston cylinder; 4-2, disc piston; 4-3, balance chamber; 4-4, metering chamber; 4-5, piston rod; 4-6, servo motor; 4-7, reducer; 4-8, coupling; 4-9, screw rod; 4-10, guide plate; 4-11, guide column; 4-12, grating ruler;

[0026] 6-1, stagnation container; 6-2, nozzle installation station; 6-3, back pressure container; 6-4, fourteenth switch valve; 6-5, fifteenth switch valve; 6-6, vacuum pump; 6-7, first muffler;

[0027] 7-1, flow meter installation station; 7-2, seventeenth switch valve; 7-3, needle regulating valve; 7-4, flow regulating valve; 7-5, sixteenth switch valve; 7-6, second muffler; 7-7, third muffler. DETAILED DESCRIPTION

[0028] The utility model is further described below in conjunction with the accompanying drawings.

[0029] like Figure 1 As shown, the utility model is a high-pressure adjustable active disc-type piston type gas flow standard device, comprising a gas source processing module 2, a pressure regulating module 3, a manifold 1, a disc-type piston device and a detection test bench.

[0030] The manifold 1 is connected to the atmosphere through the intake valve 1-1, and is connected to the gas source pretreatment module through the pressure regulating module 3. The manifold 1 is connected to one or more disc-type piston devices in parallel through the upstream pipeline, and the disc-type piston device is connected to the detection test bench through the downstream pipeline; the disc-type piston device includes a piston cylinder 4-1, in which a disc-type piston 4-2 is arranged, the piston cylinder 4-1 is a sealed cavity, the disc-type piston 4-2 divides the piston cylinder 4-1 into a balancing chamber 4-3 and a metering chamber 4-4, and a differential pressure sensor is arranged between the balancing chamber 4-3 and the metering chamber 4-4, wherein the upstream pipeline is connected to the balancing chamber 4-3, the downstream pipeline is connected to the metering chamber 4-4, and the balancing chamber 4-3 and the metering chamber 4-4 are connected through a connecting pipeline, valves are arranged on each pipeline, the piston is connected to a piston rod 4-5, the piston rod 4-5 passes through the balancing chamber 4-3 and extends out of the piston cylinder 4-1 to be connected to the driving mechanism.

[0031] In this specific embodiment, the manifold 1 is used to connect with multiple pipelines, and the gas source first enters the manifold 1, and then enters the subsequent pipeline through the manifold 1. The manifold 1 is connected to the atmosphere through the air intake valve 1-1, and is also connected to the gas source pretreatment module through the pressure regulating module 3. After opening the air intake valve 1-1, the manifold 1 is directly connected to the atmosphere, and the gas pressure in the manifold 1 is balanced with the atmospheric pressure. When a high-pressure gas source is needed, the air intake valve 1-1 needs to be closed, and the air passes through the gas source pretreatment module to form a high-pressure gas source. The high-pressure gas source is then regulated by the pressure regulating group, so that the air pressure in the manifold 1 is the required size.

[0032] The air source pretreatment module includes an air compressor 2-1, a buffer container 2-2, a high-pressure dehumidifier 2-3, a first switch valve 2-4, a gas storage container 2-5, a first heat exchanger 2-6 and a fourth pressure reducing valve 2-7 which are connected in sequence. The gas storage container 2-5 is a gas storage tank group.

[0033] In this embodiment, the pressure regulating module 3 includes a first pressure regulating pipeline 3-1 and a second pressure regulating pipeline 3-2 connected in parallel. A first pressure reducing valve 3-3 and a second switch valve 3-4 are sequentially arranged on the first pressure regulating pipeline 3-1. The pressure regulating range of the first pressure reducing valve 3-3 is (100~500) kPa gauge pressure. A second pressure reducing valve 3-5, a third pressure reducing valve 3-6 and a third switch valve 3-7 are sequentially arranged on the second pressure regulating pipeline 3-2. When the second pressure reducing valve 3-5 and the third pressure reducing valve 3-6 work together, the pressure regulating range is (10-100) kPa gauge pressure.

[0034] In the utility model, there can be only one disc-shaped piston device, or there can be a plurality of disc-shaped piston devices connected in parallel with each other.

[0035] In this embodiment, two parallel disc-type piston devices are provided, and the specifications of the two disc-type piston devices are different. The operating flow range of one disc-type piston device is (0.1~30) L / min, and the operating flow range of the other disc-type piston device is (1~500) L / min, so that the testable flow range of the gas flow standard device of this embodiment is (0.1~500) L / min.

[0036] The disc-type piston device is an active piston device, that is, the movement of the piston is driven by a driving mechanism, which is connected to a piston rod 4-5 extending out of the piston cylinder 4-1. In order to ensure the smooth operation of the piston rod 4-5, an auxiliary guide structure is also provided.

[0037] The driving mechanism includes a servo motor 4-6, a reducer 4-7, a coupling 4-8 and a ball screw 4-9. The ball screw 4-9 is connected to a screw nut fixed at the end of the piston rod 4-5. The servo motor 4-6 rotates, and the ball screw 4-9 is driven to rotate together through the reducer 4-7 and the coupling 4-8. The piston rod 4-5 is driven to translate under the action of the ball screw 4-9 and the screw nut. The servo motor 4-6 itself has a PID adjustment function, through which the PID adjustment of the piston can be realized, and the output flow of the disc-type piston device metering chamber 4-4 can be fine-tuned to balance the gas pressure in the metering chamber 4-4.

[0038] A guide column 4-11 parallel to the piston rod 4-5 is arranged on the disc-type piston device, and a guide plate 4-10 is arranged on the piston rod 4-5. The guide column 4-11 is connected to the guide plate 4-10 so that the guide plate 4-10 can only move along the guide column 4-11, thereby achieving the guiding effect on the piston rod 4-5.

[0039] At the same time, a grating ruler 4-12 is arranged on one side of the guide column 4-11. By detecting the displacement of the guide plate 4-10 through the grating ruler 4-12, the displacement of the piston rod 4-5 and the piston can be obtained.

[0040] The manifold 1 is connected to the balancing chamber 4-3 of the disc-type piston device through the upstream pipeline, and the metering chamber 4-4 is connected to the test bench through the downstream pipeline. At the same time, the balancing chamber 4-3 and the metering chamber 4-4 are connected through a connecting pipeline, and a valve is arranged on the connecting pipeline. In this way, the gas of a certain pressure from the manifold 1 first passes through the upstream pipeline and the connecting pipeline and reaches the balancing chamber 4-3 and the metering chamber 4-4 at the same time, so that the gas pressure in the balancing chamber 4-3 and the metering chamber 4-4 are the same, that is, the pressure on both sides of the disc-type piston 4-2 is the same. In this way, when the driving mechanism drives the disc-type piston 4-2 to move, since the pressure on both sides is basically the same, the disc-type piston 4-2 will not be subject to resistance from the air pressure, and the corresponding servo motor 4-6 of the driving mechanism will not be subject to additional resistance. At the same time, since the balancing chamber 4-3 and the metering chamber 4-4 are connected to each other, when the disc-type piston 4-2 moves, it can achieve dynamic balance between the balancing chamber 4-3 and the metering chamber 4-4. Before starting the test, close the valve on the connecting pipeline to disconnect the connection between the balancing chamber 4-3 and the metering chamber 4-4, but allow gas at a certain pressure to enter the balancing chamber 4-3, and still keep the gas pressure on both sides of the disc-shaped piston 4-2 basically consistent. The servo motor 4-6 controls the movement of the disc-shaped piston 4-2 to keep the pressure in the metering chamber 4-4 balanced and continuously output gas at a certain pressure and flow rate to the test bench.

[0041] A pressure difference sensor is provided between the balancing chamber 4 - 3 and the metering chamber 4 - 4 , and the pressure sensor is used to detect whether the pressures in the balancing chamber 4 - 3 and the metering chamber 4 - 4 have reached a balanced state.

[0042] The upstream pipeline includes a constant current pipeline 8 and a constant pressure pipeline connected in parallel. A flow controller group 15 and a switch valve are arranged on the constant current pipeline 8, and a switch valve is arranged on the constant pressure pipeline.

[0043] In this embodiment, the upstream pipeline includes a constant flow pipeline 8, a first constant pressure pipeline 9 and a second constant pressure pipeline 10. The constant flow pipeline 8 is provided with a flow control valve group and a second heat exchanger 16. The constant flow pipeline 8 is connected to the balance chamber 4-3 of the first disc-type piston device 4 and is connected to the balance chamber 4-3 of the second disc-type piston device 5 through the third connecting pipeline 13. A fourth switch valve 17 for controlling the connection with the first disc-type piston device 4 and an eighth switch valve 21 for controlling the connection with the second disc-type piston device 5 are provided. The first constant pressure pipeline 9 is connected to the balance chamber 4-3 of the first disc-type piston device 4, and the second constant pressure pipeline 10 is connected to the balance chamber 4-3 of the second disc-type piston device 5. A fifth switch valve 18 is provided on the first constant pressure pipeline 9, and a ninth switch valve 22 is provided on the second constant pressure pipeline 10. The balance chamber 4-3 of the first disc-type piston device 4 is connected to the metering chamber 4-4 through the first connecting pipeline 11, and a sixth switch valve 19 is provided on the first connecting pipeline 11. The balancing chamber 4-3 and the metering chamber 4-4 of the second disc-type piston device 5 are connected through the second connecting pipeline 12, and a tenth switch valve 23 is arranged on the second connecting pipeline 12. By opening and closing each valve, a constant flow or constant pressure mode can be selected, and the first disc-type piston device 4 or the second disc-type piston device 5 can be selected.

[0044] The downstream pipeline of the first disc-type piston device 4 is provided with a seventh switch valve 20 and a twelfth switch valve 25, and the downstream pipeline of the second disc-type piston device 5 is provided with an eleventh switch valve 24 and a thirteenth switch valve 26. The downstream pipeline of the first disc-type piston device 4 is connected with the downstream pipeline of the second disc-type piston device 5 through the fourth connecting pipeline 14. Through the opening and closing of each valve, it is possible to select a subsequent detection test bench for connection.

[0045] The testing bench includes a sonic nozzle testing bench 6 and a flow meter testing bench 7 .

[0046] The sonic nozzle test bench 6 includes a first test pipeline connected to the twelfth switch valve 25, on which a stagnation container 6-1, a nozzle installation station 6-2, and a back pressure container 6-3 are sequentially arranged, and the end of the first test pipeline is connected to the atmosphere through the fourteenth switch valve 6-4 and the first muffler 6-7, and at the same time, a fifteenth switch valve 6-5 and a vacuum pump 6-6 are connected in parallel at the end of the first test pipeline. The nozzle installation station 6-2 is used to connect the sonic nozzle 27 to be tested to the test pipeline, and the test method of the sonic nozzle can be selected as a positive pressure method or a negative pressure method by opening and closing the switch valve.

[0047] The flowmeter test bench 7 is used to calibrate flowmeters and flow controllers, including a second test pipeline connected to the thirteenth switch valve 26, a flowmeter installation station 7-1 is provided on the second test pipeline, a back pressure regulating valve group is connected to the end of the second test pipeline through the seventeenth switch valve 7-2, and a sixteenth switch valve 7-5 connected to the atmosphere is connected in parallel to the end of the second test pipeline. The flowmeter installation station 7-1 is used to connect the flowmeter 28 to be tested to the test pipeline.

[0048] The back pressure regulating valve group includes two branches, one of which is provided with a needle regulating valve 7-3 and a second muffler 7-6, and the other branch is provided with a flow regulating valve 7-4 and a third muffler 7-7. When the pressure in the pipeline is unstable and the gas flow needs to be controlled, the back pressure regulating valve group can be adjusted to achieve the purpose.

[0049] In addition, a humidity sensor is provided on the manifold 1, a temperature and pressure sensor is provided on the disc-type piston device, a temperature and pressure sensor is provided on the stagnation container 6-1, and a temperature and pressure sensor is also provided on the second detection pipeline. The temperature, humidity and pressure of the entire system are monitored through various sensors.

[0050] The utility model also discloses a calibration method based on a high-pressure adjustable active disc-type piston-type gas flow standard device.

[0051] When the flow controller is verified and calibrated, the constant pressure working mode is adopted, and the first disc-type piston device 4 is selected as the calibrator. The specific working process is as follows:

[0052] (1) Open the fifth on-off valve 18, the sixth on-off valve 19, the seventh on-off valve 20 and the thirteenth on-off valve 26, and close the fourth on-off valve 17 at the same time, supply air to the first disc-type piston device 4 and the flow controller to be tested through the constant pressure pipeline, set the target flow of the flow controller to be tested, and adjust the needle-type regulating valve in the back pressure regulating valve group so that the pressure of the pipeline reaches the required working pressure, which generally needs to be above 100 kPa, so that the flow controller to be tested is in the pre-operation state.

[0053] (2) Start the servo motor 4-6, which drives the ball screw 4-9 to rotate at a stable speed. The ball screw 4-9 drives the piston rod 4-5 to move to the left, so that the piston rod 4-5 is reset to the head of the piston cylinder 4-1.

[0054] (3) The speed of the servo motor 4-6 is initially set according to the target flow value of the flow controller to be inspected. The servo motor 4-6 drives the ball screw 4-9 to rotate at a stable speed. The ball screw 4-9 drives the piston rod 4-5 to move to the right, and the reading head of the grating ruler 4-12 moves synchronously with the piston rod 4-5. When the balance chamber 4-3 and the metering chamber 4-4 of the piston reach flow balance, the sixth switch valve 19 is closed, the piston device PID adjustment is started, and the flow output of the piston is fine-tuned to keep the pressure in the metering chamber 4-4 balanced, and the verification and calibration work is started.

[0055] (4) Real-time recording of the temperature, pressure, humidity of the piston and the flow controller being tested, the grating scale 4-12 displacement signal, and the piston movement time.

[0056] (5) After the verification and calibration work is completed, control the servo motor 4-6 to rotate in the opposite direction until the piston returns to the head of the piston cylinder 4-1, and then repeat the above steps (1) to (4).

[0057] When the flow meter is verified and calibrated, the constant flow working mode is adopted, and the first disc-type piston device 4 is selected as the calibrator. The specific working process is as follows:

[0058] (1) The pressure regulating module 3 is adjusted to initially set the target flow of the flow controller group 15 according to the target flow value of the flow meter 28 under test, and the fourth switch valve 17, the sixth switch valve 19, the seventh switch valve 20 and the thirteenth switch valve 26 are opened, and the fifth switch valve 18 is closed. According to the pressure requirement of the flow meter 28 under test, the sixteenth switch valve 7-5 or the seventeenth switch valve 7-2 is opened, and the needle control valve or the flow control valve 7-4 in the back pressure control valve group is fine-tuned to make the flow meter 28 under test in the pre-operation state at the target flow.

[0059] (2) Start the servo motor 4-6, which drives the ball screw 4-9 to rotate at a stable speed. The ball screw 4-9 drives the piston rod 4-5 to move to the left, so that the piston rod 4-5 is reset to the head of the piston cylinder 4-1.

[0060] (3) The speed of the servo motor 4-6 is initially set according to the target flow value of the flow meter 28 to be tested. The servo motor 4-6 drives the ball screw 4-9 to rotate at a stable speed. The ball screw 4-9 drives the piston rod 4-5 to move rightward in translation. The reading head of the grating ruler 4-12 moves synchronously with the piston rod 4-5. When the balance chamber 4-3 and the metering chamber 4-4 of the piston reach flow balance, the sixth switch valve 19 is closed, and the PID adjustment of the piston device is started. After the flow output of the piston is balanced with the target flow of the flow controller group 15, the verification and calibration work is started.

[0061] (4) Real-time recording of the temperature, pressure, humidity of the piston and the flow meter 28 being tested, the displacement signal of the grating scale 4-12, and the piston movement time.

[0062] (5) After the verification and calibration work is completed, control the servo motor 4-6 to rotate in the opposite direction until the piston returns to the head of the piston cylinder 4-1, and then repeat the above steps (1) to (4).

[0063] The methods for calibrating sonic nozzles include positive pressure method and negative pressure method.

[0064] The first disc-type piston device 4 is selected as the calibrator, and the specific process of the positive pressure method is as follows:

[0065] (1) The gas source module provides a high-pressure gas source, closes the fourth switch valve 17 and the fifteenth switch valve 6-5, opens the fifth switch valve 18, the sixth switch valve 19, the seventh switch valve 20, the twelfth switch valve 25 and the fourteenth switch valve 6-4, and adjusts the pressure regulating module 3 so that the sonic nozzle 27 under test reaches the critical back pressure ratio.

[0066] (2) Start the servo motor 4-6, which drives the ball screw 4-9 to rotate at a stable speed. The ball screw 4-9 drives the piston rod 4-5 to move to the left, so that the piston rod 4-5 is reset to the head of the piston cylinder 4-1.

[0067] (3) The speed of the servo motor 4-6 is initially set according to the target flow value of the sonic nozzle 27 to be inspected. The servo motor 4-6 drives the ball screw 4-9 to rotate at a stable speed. The ball screw 4-9 drives the piston rod 4-5 to move rightward in translation. The reading head of the grating ruler 4-12 moves synchronously with the piston rod 4-5. When the balance chamber 4-3 and the metering chamber 4-4 of the piston reach flow balance, the sixth switch valve 19 is closed, the piston device PID adjustment is started, and the flow output of the piston is fine-tuned to keep the pressure in the metering chamber 4-4 balanced, and the verification and calibration work is started.

[0068] (4) Real-time recording of the temperature, pressure, humidity of the piston and the sonic nozzle 27 being tested, the displacement signal of the grating scale 4-12, and the piston movement time.

[0069] (5) After the verification and calibration work is completed, control the servo motor 4-6 to rotate in the opposite direction until the piston returns to the head of the piston cylinder 4-1, and then repeat the above steps (1) to (4).

[0070] The first disc-type piston device 4 is selected as the calibrator, and the specific process of the negative pressure method is as follows:

[0071] (1) Close the first switch valve 2-4 and the third pressure reducing valve 3-6 of the gas source pretreatment module, open the first switch valve 2-4, the fifth switch valve 18, the sixth switch valve 19, the seventh switch valve 20, the twelfth switch valve 25 and the fifteenth switch valve 6-5, close the fourth switch valve 17 and the fourteenth switch valve 6-4, start the vacuum pump 6-6, reduce the downstream pressure of the device, and make the back pressure of the sonic nozzle 27 under test reach the critical back pressure ratio.

[0072] (2) Start the servo motor 4-6, which drives the ball screw 4-9 to rotate at a stable speed. The ball screw 4-9 drives the piston rod 4-5 to move to the left, so that the piston rod 4-5 is reset to the head of the piston cylinder 4-1.

[0073] (3) The speed of the servo motor 4-6 is initially set according to the target flow value of the sonic nozzle 27 to be inspected. The servo motor 4-6 drives the ball screw 4-9 to rotate at a stable speed. The ball screw 4-9 drives the piston rod 4-5 to move rightward in translation. The reading head of the grating ruler 4-12 moves synchronously with the piston rod 4-5. When the balance chamber 4-3 and the metering chamber 4-4 of the piston reach flow balance, the sixth switch valve 19 is closed, the piston device PID adjustment is started, and the flow output of the piston is fine-tuned to keep the pressure in the metering chamber 4-4 balanced, and the verification and calibration work is started.

[0074] (4) Record the temperature, pressure, humidity of the piston and the sonic nozzle 27 being tested, the displacement signal of the grating scale 4-12, and the piston movement time.

[0075] (5) After the verification and calibration work is completed, control the servo motor 4-6 to rotate in the opposite direction until the piston returns to the head of the piston cylinder 4-1, and then repeat the above steps (1) to (4).

[0076] In each of the above methods, the second disc-type piston device 5 can also be selected as needed. When the second disc-type piston device 5 is selected, the method is basically the same as the above steps, and those skilled in the art can obtain it based on conventional reasoning, which will not be repeated here.

Claims

1. A high-pressure adjustable active disc piston gas flow standard device, characterized in that: It includes a manifold, which is connected to the atmosphere through an air inlet valve, and is connected to an air source pretreatment module through a pressure regulating module; the manifold is connected to one or more disc-type piston devices in parallel through an upstream pipeline, and the disc-type piston device is connected to a detection test bench through a downstream pipeline; the disc-type piston device includes a piston cylinder, a disc-type piston is arranged in the piston cylinder, the piston cylinder is a sealed cavity, the disc-type piston divides the piston cylinder into a balancing chamber and a metering chamber, and a differential pressure sensor is arranged between the balancing chamber and the metering chamber, wherein the upstream pipeline is connected to the balancing chamber, the downstream pipeline is connected to the metering chamber, and the balancing chamber and the metering chamber are connected through a connecting pipeline, valves are arranged on each pipeline, and the piston is connected to a piston rod, and the piston rod passes through the balancing chamber and extends out of the piston cylinder to be connected to a driving mechanism.

2. The high-pressure adjustable active disc piston type gas flow standard device according to claim 1 is characterized in that: The driving mechanism comprises a servo motor, a reducer, a coupling and a screw rod. The outer end of the piston rod is connected to a guide column through a guide plate, and a grating ruler is arranged on one side of the guide column.

3. The high-pressure adjustable active disc piston type gas flow standard device according to claim 1 is characterized in that: There are two disc-type piston devices in total, and the operating flow ranges of the two disc-type piston devices are 0.1-30 L / min and 1-500 L / min respectively.

4. The high-pressure adjustable active disc piston type gas flow standard device according to claim 1 is characterized in that: The air source pretreatment module comprises an air compressor, a buffer container, a high-pressure dehumidifier, a switch valve, a gas storage container, a heat exchanger and a pressure reducing valve which are connected in sequence.

5. The high-pressure adjustable active disc piston type gas flow standard device according to claim 1 is characterized in that: The pressure regulating module comprises a first pressure regulating pipeline and a second pressure regulating pipeline connected in parallel, a pressure reducing valve and a switch valve are sequentially arranged on the first pressure regulating pipeline, and two pressure reducing valves and a switch valve are sequentially arranged on the second pressure regulating pipeline.

6. The high-pressure adjustable active disc piston type gas flow standard device according to claim 1 is characterized in that: The upstream pipeline includes a constant current pipeline and a constant pressure pipeline connected in parallel, a flow controller group and a switch valve are arranged on the constant current pipeline, and a switch valve is arranged on the constant pressure pipeline.

7. The high-pressure adjustable active disc piston type gas flow standard device according to claim 1 is characterized in that: The detection test bench includes a sonic nozzle detection test bench and a flow meter detection test bench.

8. The high-pressure adjustable active disc piston type gas flow standard device according to claim 7 is characterized in that: The sonic nozzle detection test bench includes a first detection pipeline, on which a stagnation container, a nozzle installation station, and a back pressure container are sequentially arranged, and the end of the first detection pipeline is connected to the atmosphere and is connected in parallel with a vacuum pump.

9. The high-pressure adjustable active disc piston type gas flow standard device according to claim 7, characterized in that: The flow meter test bench includes a second test pipeline, on which a flow meter installation station is arranged, and at the end of the second test pipeline, a back pressure regulating valve group is connected and a branch connected to the atmosphere is connected in parallel.

Images