A high-precision flow meter performance test system and test method

Abstract

The present invention discloses a high-precision flowmeter performance test system and a test method thereof. The system comprises a storage tank, a fluid pump, a detection pipeline and a weighing device. The fluid pump delivers a liquid medium in the storage tank to the detection pipeline. The detection pipeline comprises a standard flow meter, a flow meter to be measured and a joint which are connected in sequence. The weighing device is provided with a sealed container which can be connected to the joint. The detection pipeline is also provided with a flow regulating valve. The flow regulating valve is used to regulate and stabilize the flow velocity of the detection pipeline during the detection time, thereby solving the fluctuation influence of the tank pressure change on the flow velocity in the detection pipeline when the sealed container is filled, and improving the detection accuracy of the flow meter to be measured.

Description

Technical Field

[0001] The invention belongs to the technical field of flow meter calibration, and in particular relates to a high-precision flow meter performance testing system and a testing method thereof. Background Art

[0002] After the preparation of the low-temperature flow meter is completed, the flow meter needs to be tested to ensure its accuracy. In the prior art, the standard meter method or the weighing method at room temperature is often used for testing. The quality method at room temperature is that the liquid medium in the container is not transported to the detection pipeline by a pump. The liquid medium flows into the sealed container after passing through the standard meter and the flow meter to be measured. The controller is used to obtain the mass data of the liquid medium in the weighed and filled sealed container and the flow data measured by the flow meter to be measured for comparison, so as to achieve the accuracy measurement of the flow meter to be measured. However, during the detection process, since the measurement data of the flow meter to be measured needs to be converted into electrical signals before it can be obtained by the controller, there is a time difference between the measured flow value sensed by the flow meter to be measured and the corresponding flow value obtained by the controller, such as Figure 1 Described, the x-axis is the time axis t, and the y-axis is the instantaneous flow Q detected by the flow meter to be measured; the flow rate data of the flow meter to be measured obtained by the controller at the measurement start time t1 should actually be the data detected by the flow meter to be measured at time t0 before t1, and similarly, the flow rate data of the flow meter to be measured obtained by the controller at the measurement end time t4 should actually be the data detected by the flow meter to be measured at time t3 before t4; in addition, since the air pressure in the sealed container will change when the fluid medium enters the sealed container, the air pressure in the sealed container will act on the detection pipeline, and the air pressure will cause fluctuations in the flow rate in the detection pipeline. Therefore, the total flow data (S1+S2) of the flow meter to be measured obtained by the controller during the detection time t1-t4 is different from the total flow data (S2+S3) actually measured by the flow meter to be measured, which affects the detection accuracy of the flow meter to be measured and causes errors in the results of subsequent measurement and verification. Summary of the invention

[0003] It can be seen that the cryogenic flow meter does not have a set of source-level measuring equipment to calibrate the flow meter in the actual low-temperature state. Therefore, in order to solve the problem that the cryogenic flow meter cannot be traced in the actual flow state of the cryogenic medium, the present invention provides a high-precision flow meter performance test system and a test method thereof, which reduces the fluctuation effect of the air pressure on the flow velocity in the detection pipeline when filling the sealed container, and improves the detection accuracy of the flow meter to be tested.

[0004] The embodiments of the present invention are implemented by the following technical solutions:

[0005] A high-precision flow meter performance test system includes a storage tank, a fluid pump, a detection pipeline and a weighing device. The fluid pump pumps the liquid medium in the storage tank to the detection pipeline. The detection pipeline includes a standard flow meter, a flow meter to be measured and a joint connected in sequence. The weighing device is provided with a sealed container that can be connected to the joint. The detection pipeline is also equipped with a flow regulating valve.

[0006] The flow regulating valve is arranged between the flow meter to be measured and the joint.

[0007] The detection pipeline also includes a reversing valve and a liquid return pipeline. The inlet of the reversing valve is connected to the flow meter to be measured. The reversing valve is configured with an outlet connected to the liquid return pipeline. The other interface of the reversing valve is connected to the joint. Preferably, the flow regulating valve is configured between the reversing valve and the joint, and the liquid return pipeline is connected to the storage tank.

[0008] A gas-liquid separator is also arranged between the fluid pump and the standard flow meter.

[0009] A method for testing a high-precision flowmeter performance test system, using the high-precision flowmeter performance test system, comprises the following steps:

[0010] S1. When the joint is connected to the sealed container, the liquid medium begins to be filled into the sealed container at time t1, and the instantaneous flow value V0 obtained by the controller at this time is set as the initial flow value;

[0011] S2. Starting from time t1, the flow meter to be measured measures the instantaneous flow value Vi (i = positive integer) at each moment, the controller obtains the instantaneous flow value Vi, and compares Vi with V0;

[0012] S3. If Vi is not equal to V0, the controller controls the flow rate through the flow meter to be measured through the flow control valve so that Vi is equal to V0;

[0013] S4. At time t4, the filling of liquid medium into the sealed container is completed. The total amount of liquid medium Q0 flowing through the flow meter to be measured within the time period T is measured by the flow meter to be measured, the total amount of liquid medium Q1 flowing through the standard flow meter to be measured within the time period T is measured by the standard flow meter, and the mass of liquid medium Q2 weighed by the weighing device within the time period T is read out. Compare Q0, Q1 and Q2 to complete the calibration of the flow meter to be measured, wherein time T = t4-t1.

[0014] A method for testing a high-precision flowmeter performance test system, using the high-precision flowmeter performance test system, comprises the following steps:

[0015] S1. When the joint is connected to the sealed container, the liquid medium begins to be filled into the sealed container at time t1, and the instantaneous flow value V0 obtained by the controller at this time is set as the initial flow value;

[0016] S2. When filling reaches time t1, the flow meter to be measured measures the instantaneous flow value Vi (i = positive integer) at this time and every time thereafter, and the controller obtains the instantaneous flow value Vi;

[0017] S3. When filling to time t2, compare Vi with V0. If Vi and V0 are not equal, the controller controls the flow rate through the flow meter to be measured through the flow control valve to make Vi and V0 equal;

[0018] S4. At time t3, the instantaneous flow rate V3 measured by the flow meter to be measured is equal to V0, and after time t3, the instantaneous flow rate measured by the flow meter to be measured is equal to V0;

[0019] S5. At time t4, the filling of the liquid medium into the sealed container is finished, the total amount of liquid medium Q0 flowing through the flow meter to be measured in the time period T is measured by the flow meter to be measured, the total amount of liquid medium Q1 flowing through the standard flow meter to be measured in the time period T is measured by the standard flow meter, and the mass of liquid medium Q2 weighed by the weighing device in the time period T is read out, and Q0, Q1 and Q2 are compared to complete the calibration of the flow meter to be measured, wherein time T = t4-t1;

[0020] Assume that the time difference from the flow meter to be measured to the controller obtaining the corresponding flow value is Δt, Δt <t4-t3。

[0021] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0022] The present invention configures a flow regulating valve in the detection pipeline and uses the flow regulating valve to regulate the flow velocity in the detection pipeline to stabilize the flow during the detection time, thereby solving the fluctuation effect of air pressure on the flow velocity in the detection pipeline during the filling of a sealed container and improving the detection accuracy of the flow meter to be measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a time t-flow Q coordinate diagram of the flow meter to be measured when the flow meter to be measured is measured by the weighing method in the prior art;

[0025] Figure 2 This is a schematic diagram of the structure of Example 1 of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of Example 2 of the present invention;

[0027] Figure 4 The time t-flow rate V coordinate diagram of the flow meter to be measured when the flow meter to be measured is measured by using Example 3 of the present invention;

[0028] Figure 5 The time t-flow rate V coordinate diagram of the flow meter to be measured when the flow meter to be measured is measured by using Example 4 of the present invention;

[0029] Icons: 1-storage tank, 2-fluid pump, 3-weighing device, 30-sealed container, 4-standard flow meter, 5-flow meter to be measured, 6-connector, 7-flow regulating valve, 8-gas-liquid separator, 9-reversing valve, 10-return liquid pipeline. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0033] In the description of the present invention, it should be noted that if the terms "inside" or "outside" appear to indicate an orientation or position relationship, it is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the invention is usually placed when in use. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0034] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "configure", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] Example 1

[0036] Please refer to Figure 2 The present embodiment provides a high-precision flow meter performance test system, including a storage tank 1, a fluid pump 2, a detection pipeline and a weighing device 3. The storage tank 1 stores a liquid medium. The fluid pump 2 pumps the liquid medium in the storage tank 1 to the detection pipeline. The detection pipeline includes a standard flow meter 4, a flow meter to be measured 5 and a connector 6 connected in sequence. The standard flow meter 4 is a flow meter with higher measurement accuracy and is used to calibrate the accuracy of the flow meter to be measured 5. The weighing device 3 is provided with a sealed container 30 that can be connected to the connector 6. The load-bearing device is arranged at the bottom of the sealed container 30 for weighing and measuring. The detection pipeline is also provided with a flow regulating valve 7.

[0037] Through the above arrangement, when the performance test is performed on the flow meter 5 to be tested, the fluid pump 2 is started to pump the liquid medium in the storage tank 1 into the detection pipeline, and the liquid medium flows into the sealed container 30 through the standard flow meter 4 and the flow meter 5 to be tested in turn, and the flow regulating valve 7 in the detection pipeline stabilizes the flow of the fluid medium, thereby reducing the influence of the air pressure in the sealed container 30 on the flow velocity in the detection pipeline when the fluid medium is filled, thereby improving the detection accuracy of the flow meter 5 to be tested.

[0038] In this embodiment, the flow regulating valve 7 is further configured between the flow meter to be measured 5 and the connector 6, so that the flow regulating valve 7 can timely adjust the detection pipeline to reduce the detection impact on the flow meter to be measured 5. It should be noted that in other embodiments, the flow regulating valve 7 is configured between the standard flow meter 4 and the flow meter to be measured 5, or the flow regulating valve 7 is configured between the fluid pump 2 and the standard flow meter 4.

[0039] In this embodiment, in order to prevent the air in the liquid medium from affecting the test, a gas-liquid separator 8 is further arranged between the fluid pump 2 and the standard flow meter 4 .

[0040] Example 2

[0041] Please refer to Figure 3This embodiment provides a high-precision flow meter performance test system, whose basic structure is the same as that of embodiment 1, and the difference of this embodiment is that: the detection pipeline also includes a reversing valve 9 and a return liquid pipeline 10, the inlet of the reversing valve 9 is connected to the flow meter 5 to be measured, the reversing valve 9 is configured with an outlet connected to the return liquid pipeline 10, and the other interface of the reversing valve 9 is connected to the connector 6. Preferably, the flow regulating valve 7 is configured between the reversing valve 9 and the connector 6, and the return liquid pipeline 10 is connected to the storage tank 1. The return liquid pipeline 10 can be used to realize the standard meter test.

[0042] Example 3

[0043] Please refer to Figure 2 and Figure 4 This embodiment provides a method for testing a high-precision flow meter performance test system. When the high-precision flow meter performance test system described in Embodiment 1 is used, the method includes the following steps:

[0044] S1. Start the fluid pump 2. When the connector 6 is connected to the sealed container 30, the liquid medium begins to be filled into the sealed container 30 at time t1. The instantaneous flow value V0 obtained by the controller at this time is set as the initial flow value;

[0045] S2. From time t1, the flow meter 5 to be measured measures the instantaneous flow value Vi (i = positive integer) at each moment, the controller obtains the instantaneous flow value Vi, and compares Vi with V0;

[0046] S3. If Vi is not equal to V0, the controller controls the flow rate through the flow meter 5 to be measured through the flow control valve 7 so that Vi is equal to V0;

[0047] S4. At time t4, the filling of liquid medium into the sealed container 30 is completed, the total amount Q0 of liquid medium flowing through the flow meter 5 to be measured within the time period T is measured by the flow meter 5 to be measured, the total amount Q1 of liquid medium flowing through the standard flow meter 4 to be measured within the time period T is measured by the standard flow meter 4, the mass Q2 of liquid medium weighed by the weighing device 3 within the time period T is read out, Q0, Q1 and Q2 are compared, and the calibration of the flow meter 5 to be measured is completed, wherein the time T = t4-t1.

[0048] Please refer to Figure 3 and Figure 4 When the high-precision flow meter performance test system described in Example 2 is used in this embodiment, the following steps are included:

[0049] S1. Close the connection between the reversing valve 9 and the joint 6 and the sealed container 30, open the connection between the reversing valve 9 and the liquid return pipeline 10, start the fluid pump 2, and the fluid medium passes through the standard flow meter 4 and the flow meter to be measured 5 and then returns to the storage tank 1 through the liquid return pipeline 10. When the controller detects that the flow rate of the liquid medium in the detection pipeline 10 is stable, the reversing valve 9 is switched, the connection with the liquid return pipeline 10 is closed, and the connection with the joint 6 and the sealed container 30 is opened. This time is counted as time t1, and the liquid medium begins to be filled into the sealed container 30. The instantaneous flow value V0 obtained by the controller at this time is set as the initial flow value. The reversing valve 9 and the liquid return pipeline 10 are used to enable the controller to more accurately obtain the flow value V0 in the steady flow state;

[0050] S2. From time t1, the flow meter 5 to be measured measures the instantaneous flow value Vi (i = positive integer) at each moment, the controller obtains the instantaneous flow value Vi, and compares Vi with V0;

[0051] S3. If Vi is not equal to V0, the controller controls the flow rate through the flow meter 5 to be measured through the flow control valve 7 so that Vi is equal to V0;

[0052] S4. At time t4, the filling of liquid medium into the sealed container 30 is completed, the total amount Q0 of liquid medium flowing through the flow meter 5 to be measured within the time period T is measured by the flow meter 5 to be measured, the total amount Q1 of liquid medium flowing through the standard flow meter 4 to be measured within the time period T is measured by the standard flow meter 4, the mass Q2 of liquid medium weighed by the weighing device 3 within the time period T is read out, Q0, Q1 and Q2 are compared, and the calibration of the flow meter 5 to be measured is completed, wherein the time T = t4-t1.

[0053] Please refer to Figure 4 Through the test method of the flow meter performance test system of this embodiment, the flow rate in the detection time period T is stabilized by the flow regulating valve 7. In the T time period, the total amount of liquid medium Q0 obtained by the controller through the flow meter 5 to be tested is (S1+S2), and the weight of the liquid medium actually measured by the flow meter 5 to be tested in the T time period is Q(S2+S3). It can be seen that Q0=Q, thereby avoiding the fluctuation influence of the air pressure of the filling sealed container 30 on the flow rate in the detection pipeline during weighing measurement, and having higher measurement accuracy.

[0054] Example 4

[0055] This embodiment provides a method for testing a high-precision flow meter performance test system. When the high-precision flow meter performance test system described in Embodiment 1 is used, the method comprises the following steps:

[0056] S1. Start the fluid pump 2. When the connector 6 is connected to the sealed container 30, the liquid medium begins to be filled into the sealed container 30 at time t1. The instantaneous flow value V0 obtained by the controller at this time is set as the initial flow value;

[0057] S2. When filling reaches time t1, the flow meter 5 to be measured measures the instantaneous flow value Vi (i = positive integer) at this time and every time thereafter, and the controller obtains the instantaneous flow value Vi;

[0058] S3. When filling to time t2, compare Vi with V0. If Vi and V0 are not equal, the controller controls the flow rate through the flow meter 5 to be measured through the flow control valve 7 so that Vi and V0 are equal;

[0059] S4. At time t3, the instantaneous flow rate V3 measured by the flow meter 5 to be measured is equal to V0, and after time t3, the instantaneous flow rate measured by the flow meter 5 to be measured is equal to V0;

[0060] S5. At time t4, the filling of the liquid medium into the sealed container 30 is finished, the total amount of liquid medium Q0 flowing through the flow meter 5 to be measured in the T time period is measured by the flow meter 5 to be measured, the total amount of liquid medium Q1 flowing through the standard flow meter 4 to be measured in the T time period is measured by the standard flow meter 4, the mass Q2 of the liquid medium weighed by the weighing device 3 in the T time period is read, Q0, Q1 and Q2 are compared, and the calibration of the flow meter 5 to be measured is completed, wherein the time T = t4-t1;

[0061] Assume that the time difference from the flow meter 5 to the controller obtaining the corresponding flow value is Δt, Δt <t4-t3。

[0062] This embodiment, when using the high-precision flow meter performance test system described in Embodiment 2, includes the following steps:

[0063] S1. The reversing valve 9 is used to close the connection between the joint 6 and the sealed container 30, and the connection between the joint 6 and the liquid return line 10, and the fluid pump 2 is started. The fluid medium passes through the standard flow meter 4 and the flow meter to be measured 5 and then returns to the storage tank 1 through the liquid return line 10. When the controller detects that the flow rate of the liquid medium in the detection line is stable, the reversing valve 9 is switched, the connection with the liquid return line 10 is closed, and the joint 6 is opened to communicate with the sealed container 30. The joint 6 is connected to the sealed container 30, and the liquid medium begins to be filled into the sealed container 30 at time t1. The instantaneous flow value V0 obtained by the controller at this time is set as the initial flow value;

[0064] S2. When filling reaches time t1, the flow meter 5 to be measured measures the instantaneous flow value Vi (i = positive integer) at this time and every time thereafter, and the controller obtains the instantaneous flow value Vi;

[0065] S3. When filling to time t2, compare Vi with V0. If Vi and V0 are not equal, the controller controls the flow rate through the flow meter 5 to be measured through the flow control valve 7 so that Vi and V0 are equal;

[0066] S4. At time t3, the instantaneous flow rate V3 measured by the flow meter 5 to be measured is equal to V0, and after time t3, the instantaneous flow rate measured by the flow meter 5 to be measured is equal to V0;

[0067] S5. At time t4, the filling of the liquid medium into the sealed container 30 is finished, the total amount of liquid medium Q0 flowing through the flow meter 5 to be measured in the T time period is measured by the flow meter 5 to be measured, the total amount of liquid medium Q1 flowing through the standard flow meter 4 to be measured in the T time period is measured by the standard flow meter 4, the mass Q2 of the liquid medium weighed by the weighing device 3 in the T time period is read, Q0, Q1 and Q2 are compared, and the calibration of the flow meter 5 to be measured is completed, wherein the time T = t4-t1;

[0068] Assume that the time difference from the flow meter 5 to the controller obtaining the corresponding flow value is Δt, Δt <t4-t3。

[0069] Please refer to Figure 5 Through the test method of the flow meter performance test system of this embodiment, the flow rate in the detection time period t2-t4 is stabilized by the flow regulating valve 7. The total amount of liquid medium Q0 obtained by the controller through the flow meter 5 to be tested in the T time period should be (S1+S2+S3), and the weight of the liquid medium actually measured by the flow meter 5 to be tested in the T time period is Q(S2+S3+S4). It can be seen that Q0=Q. It also avoids the fluctuation influence of the air pressure of the filling sealed container 30 on the flow rate in the detection pipeline during weighing measurement, and has higher measurement accuracy.

[0070] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-precision flowmeter performance test system, comprising a storage tank, a fluid pump, a detection pipeline and a weighing device, wherein the fluid pump delivers the liquid medium in the storage tank to the detection pipeline, the detection pipeline comprises a standard flow meter, a flow meter to be measured and a joint connected in sequence, and the weighing device is provided with a sealed container that can be connected to the joint, characterized in that: The detection pipeline is also equipped with a flow regulating valve.

2. A high-precision flow meter performance test system according to claim 1, characterized in that: The flow regulating valve is arranged between the flow meter to be measured and the joint.

3. A high-precision flow meter performance test system according to claim 1, characterized in that: The detection pipeline also includes a reversing valve and a liquid return pipeline. The inlet of the reversing valve is connected to the flow meter to be measured. The reversing valve is configured with an outlet connected to the liquid return pipeline. The other interface of the reversing valve is connected to the flow regulating valve. The flow regulating valve is connected to the joint. The liquid return pipeline is connected to the storage tank.

4. A high-precision flow meter performance test system according to any one of claims 1-4, characterized in that: A gas-liquid separator is also arranged between the fluid pump and the standard flow meter.

5. A test method for a high-precision flow meter performance test system, characterized in that: A high-precision flow meter performance test system according to any one of claims 1-2 comprises the following steps: S1. Start the fluid pump. When the joint is connected to the sealed container, the liquid medium begins to be filled into the sealed container at time t1. The instantaneous flow value V0 obtained by the controller at this time is set as the initial flow value; S2. Starting from time t1, the flow meter to be measured measures the instantaneous flow value Vi at each moment, i = a positive integer, the controller obtains the instantaneous flow value Vi, and compares Vi with V0; S3. If Vi is not equal to V0, the controller controls the flow rate through the flow meter to be measured through the flow control valve so that Vi is equal to V0; S4. At time t4, the filling of liquid medium into the sealed container is finished. The total amount of liquid medium Q0 that passes through the flow meter to be measured within the time period T is read out, and the total amount of liquid medium Q1 that passes through the standard flow meter within the time period T is read out. The mass Q2 of the liquid medium weighed by the weighing device within the time period T is read out, and Q0, Q1 and Q2 are compared to complete the calibration of the flow meter to be measured, wherein the time T = t4-t1.

6. A test method for a high-precision flow meter performance test system, characterized in that: A high-precision flow meter performance test system according to claim 3 comprises the following steps: S1. Close the connection between the reversing valve and the joint and the sealed container, open the connection between the reversing valve and the liquid return pipeline, start the fluid pump, and the fluid medium passes through the standard flow meter and the flow meter to be measured and then returns to the storage tank through the liquid return pipeline. When the controller detects that the flow rate of the liquid medium in the detection pipeline is stable, the reversing valve is switched, the connection with the liquid return pipeline is closed, and the connection with the joint and the sealed container is opened. This time is counted as time t1, and the liquid medium begins to be filled into the sealed container. The instantaneous flow value V0 obtained by the controller at this time is set as the initial flow value. The reversing valve and the liquid return pipeline are used to enable the controller to more accurately obtain the flow value V0 in the steady flow state; S2. Starting from time t1, the flow meter to be measured measures the instantaneous flow value Vi at each moment, i = a positive integer, the controller obtains the instantaneous flow value Vi, and compares Vi with V0; S3. If Vi is not equal to V0, the controller controls the flow rate through the flow meter to be measured through the flow control valve so that Vi is equal to V0; S4. At time t4, the filling of liquid medium into the sealed container is completed. The total amount of liquid medium Q0 flowing through the flow meter to be measured within the time period T is measured by the flow meter to be measured, the total amount of liquid medium Q1 flowing through the standard flow meter to be measured within the time period T is measured by the standard flow meter, and the mass of liquid medium Q2 weighed by the weighing device within the time period T is read out. Compare Q0, Q1 and Q2 to complete the calibration of the flow meter to be measured, wherein time T = t4-t1.

7. A test method for a high-precision flow meter performance test system, characterized in that: A high-precision flow meter performance test system according to any one of claims 1-2 comprises the following steps: S1. Start the fluid pump. When the joint is connected to the sealed container, the liquid medium begins to be filled into the sealed container at time t1. The instantaneous flow value V0 obtained by the controller at this time is set as the initial flow value; S2. When filling reaches time t1, the flow meter to be measured measures the instantaneous flow value Vi at this time and every time thereafter, i = a positive integer, and the controller obtains the instantaneous flow value Vi; S3. When filling to time t2, compare Vi with V0. If Vi and V0 are not equal, the controller controls the flow rate through the flow meter to be measured through the flow control valve to make Vi and V0 equal; S4. At time t3, the instantaneous flow rate V3 measured by the flow meter to be measured is equal to V0, and after time t3, the instantaneous flow rate measured by the flow meter to be measured is equal to V0; S5. At time t4, the filling of the liquid medium into the sealed container is finished, the total amount of liquid medium Q0 measured by the flow meter to be measured in the time period T, the total amount of liquid medium Q1 measured by the standard flow meter in the time period T, the mass of liquid medium Q2 weighed by the weighing device in the time period T, and Q0, Q1 and Q2 are compared to complete the calibration of the flow meter to be measured, wherein time T = t4-t1; Assume that the time difference from the flow meter to be measured to the controller obtaining the corresponding flow value is Δt, Δt <t4-t3。 8. A test method for a high-precision flow meter performance test system, characterized in that: A high-precision flow meter performance test system according to claim 3 comprises the following steps: S1. Close the connection between the reversing valve and the sealed container, and the connection between the reversing valve and the liquid return line, start the fluid pump, and the fluid medium passes through the standard flow meter and the flow meter to be measured, and then returns to the storage tank through the liquid return line. When the controller detects that the flow rate of the liquid medium in the detection line is stable, switch the reversing valve, close the connection with the liquid return line, open the connection between the reversing valve and the sealed container, and the liquid medium begins to be filled into the sealed container at time t1. The instantaneous flow value V0 obtained by the controller at this time is set as the initial flow value; S2. When filling reaches time t1, the flow meter to be measured measures the instantaneous flow value Vi at this time and every time thereafter, i = a positive integer, and the controller obtains the instantaneous flow value Vi; S3. When filling to time t2, compare Vi with V0. If Vi and V0 are not equal, the controller controls the flow rate through the flow meter to be measured through the flow control valve to make Vi and V0 equal; S4. At time t3, the instantaneous flow rate V3 measured by the flow meter to be measured is equal to V0, and after time t3, the instantaneous flow rate measured by the flow meter to be measured is equal to V0; S5. At time t4, the filling of the liquid medium into the sealed container is finished, the total amount of liquid medium Q0 flowing through the flow meter to be measured in the T time period is measured by the flow meter to be measured, the total amount of liquid medium Q1 flowing through the standard flow meter to be measured in the T time period is measured by the standard flow meter, and the mass of liquid medium Q2 weighed by the weighing device in the T time period is read out, and Q0, Q1 and Q2 are compared to complete the calibration of the flow meter to be measured, wherein the time T = t4-t1; Assume that the time difference from the flow meter to be measured to the controller obtaining the corresponding flow value is Δt, Δt <t4-t3。

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