Flow meter verification system and method

Abstract

The present application relates to a kind of flowmeter verification system, including fluid medium storage tank, measuring container, fluid pushing device, the flowmeter to be examined and host computer, fluid medium storage tank, for storing fluid medium, measuring container, for receiving fluid medium, fluid pushing device, for sending fluid medium into measuring container, the flowmeter to be examined, for measuring the flow of gas that measuring container receives fluid medium after being extruded, host computer, for obtaining the weight before measuring container receives fluid medium, obtaining the weight after measuring container receives fluid medium and obtaining the flow volume of gas measured by the flowmeter to be examined, and the measurement accuracy of the flowmeter to be examined is verified according to the each value obtained.It also provides a kind of flowmeter verification method.The present application can realize the problem of automatic measurement verification of different flowmeters by the cooperation of fluid medium storage tank, measuring container, fluid pushing device, the flowmeter to be examined and host computer, improve operation convenience, test accuracy.

Description

Technical Field

[0001] This invention relates to the field of metrological verification technology, specifically to a flow meter verification system and method. Background Technology

[0002] A flow meter is an instrument used to measure the volume or mass of gas or liquid fluid passing through a cross-section of a pipe per unit time. It has wide applications in industry, commerce, and daily life. Flow meter measurement is crucial for ensuring the accuracy, efficiency, and safety of fluid transport and is an indispensable part of modern industrial society. However, for the calibration of small-flow and ultra-micro-flow flow meters, there is currently no universally accepted, effective, and reliable metrological calibration method, nor is there an automated calibration approach. Summary of the Invention

[0003] The purpose of this invention is to provide a flow meter calibration system and method, which can at least solve some of the defects in the prior art.

[0004] To achieve the above objectives, embodiments of the present invention provide the following technical solution: a flow meter calibration system, comprising a fluid medium storage tank, a measuring container, a fluid delivery device, a flow meter under test, and a host computer.

[0005] The fluid medium storage tank is used to store fluid media.

[0006] The measuring container is used to receive the fluid medium.

[0007] The fluid delivery device is used to deliver the fluid medium into the measuring container.

[0008] The flow meter under test is used to measure the flow rate of gas expelled from the measuring container after receiving the fluid medium.

[0009] The host computer is used to acquire the weight of the measuring container before receiving the fluid medium, the weight of the measuring container after receiving the fluid medium, and the flow rate and volume of the gas measured by the flow meter under test, and to verify the measurement accuracy of the flow meter under test based on the acquired values.

[0010] Furthermore, it also includes a weighing unit for recording the weight of the measuring container, the weighing unit being communicatively connected to the host computer.

[0011] Furthermore, the fluid delivery device includes a fluid delivery unit capable of drawing in the fluid medium and discharging the drawn-in fluid medium.

[0012] Furthermore, there are multiple fluid delivery units, and each fluid delivery unit cooperates to form a continuous fluid delivery device that continuously delivers fluid medium.

[0013] Furthermore, it also includes a linkage mechanism connecting the drive ends of each of the fluid delivery units.

[0014] Furthermore, it also includes a three-way valve assembly for connecting the fluid delivery device, the fluid medium storage tank, and the measuring container.

[0015] This invention provides another technical solution: a flow meter calibration method, comprising the following steps:

[0016] S1, fluid media are stored in a fluid media storage tank;

[0017] S2, a fluid delivery device is used to deliver the fluid medium in the fluid medium storage tank into the measuring container, and the headspace gas of the measuring container is squeezed out from the outlet of the measuring container;

[0018] S3, the flow rate of the gas extruded from the measuring container is measured using the flow meter under test;

[0019] S4, the weight of the measuring container before receiving the fluid medium, the weight of the measuring container after receiving the fluid medium, and the flow rate and volume of the gas measured by the flow meter under test.

[0020] S5, calculate the difference between the weight of the measuring container after receiving the fluid medium and the weight of the measuring container before receiving the fluid medium, so as to obtain the volume of the fluid medium pushed by the fluid pushing device;

[0021] S6, compare the actual volume of the fluid medium pushed by the fluid pushing device with the gas flow volume measured by the flow meter under test to verify the measurement accuracy of the flow meter under test.

[0022] Furthermore, the fluid delivery device includes a first fluid delivery unit and a second fluid delivery unit.

[0023] The first fluid delivery unit is used to extract fluid from the fluid medium storage tank, while the second fluid delivery unit is idle.

[0024] The first fluid delivery unit gradually delivers the extracted fluid medium into the measuring container, while the second fluid delivery unit gradually extracts the fluid medium from the fluid medium storage tank.

[0025] After all the fluid medium in the first fluid delivery unit has been delivered into the measuring container, the second fluid delivery unit continues to gradually deliver fluid medium into the measuring container. During this process, the first fluid delivery unit gradually extracts fluid medium from the fluid medium storage tank.

[0026] This cycle is repeated to ensure uninterrupted delivery of the fluid medium.

[0027] Furthermore, the difference between the weight of the measuring container after receiving the fluid medium and the weight of the measuring container before receiving the fluid medium is corrected to obtain the actual volume of the fluid medium pushed by the fluid pushing device. The correction formula is as follows:

[0028]

[0029] Where β is the coefficient of thermal expansion of the fluid, E is the bulk modulus of elasticity of the fluid, t is the ambient temperature, and P is the ambient pressure. This is the standard atmospheric pressure value at 25℃.

[0030] Furthermore, the fluid pushing device includes a servo motor for providing driving force. During the process of the servo motor providing driving force, the servo motor is calibrated in real time. The specific calibration method is as follows: the weight value of the measured container is fed back to the intermediate computer in real time, and the intermediate computer performs first-order differential processing on the weight value versus time mt curve.

[0031] Compared with the prior art, the beneficial effects of the present invention are: by cooperating with the fluid medium storage tank, the measuring container, the fluid pushing device, the flow meter under test and the host computer, the problem of automated measurement and verification of different flow meters can be realized, thereby improving the convenience of operation and the accuracy of testing. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of a flowmeter calibration system provided in an embodiment of the present invention;

[0033] Figure 2 This is a block diagram showing the connection of various components of a flowmeter calibration system provided in an embodiment of the present invention;

[0034] Figure 3 An mt curve diagram of a flowmeter calibration system provided in an embodiment of the present invention;

[0035] In the attached figures, the following are the reference numerals: 1-servo motor; 2-first fluid push unit; 3-second fluid push unit; 4-first three-way valve; 5-second three-way valve; 6-third three-way valve; 7-fluid medium storage tank; 8-measuring container; 9-weighing unit; 10-flow meter under test. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Please see Figure 1 and Figure 2 This invention provides a flow meter calibration system, including a fluid medium storage tank 7, a measuring container 8, a fluid delivery device, a flow meter under test 10, and a host computer. The fluid medium storage tank 7 stores the fluid medium, the measuring container 8 receives the fluid medium, the fluid delivery device delivers the fluid medium into the measuring container 8, and the flow meter under test 10 measures the flow rate of the gas expelled from the measuring container 8 after receiving the fluid medium. The host computer acquires the weight of the measuring container 8 before receiving the fluid medium, the weight of the measuring container 8 after receiving the fluid medium, and the flow rate and volume of the gas measured by the flow meter under test 10. Based on the acquired values, the measurement accuracy of the flow meter under test 10 is calibrated. The cooperation of the fluid medium storage tank 7, the measuring container 8, the fluid delivery device, the flow meter under test 10, and the host computer enables automated metrological calibration of different flow meters, improving operational convenience and testing accuracy. Specifically, the fluid medium in the fluid medium storage tank 7 can be any fluid, such as pure water. The measuring container 8 is initially empty. When the fluid delivery device sends the fluid medium into the measuring container 8, the headspace air in the measuring container 8 is expelled. This part of the measuring container 8 can be measured by the flow meter under test 10. Finally, the weight and volume data are acquired by the host computer, calculated, and compared to verify the measurement accuracy of the flow meter under test 10. The verification principle is that after the fluid medium is sent into the measuring container 8, an equal volume of gas can be expelled. Finally, by comparing the weight change of the measuring container 8 with the volume of gas measured by the flow meter under test 10, the measurement accuracy of the flow meter under test 10 can be verified. Preferably, the host computer runs a leak detection program to ensure the pipeline is sealed. The verification batch processing program is edited by the host computer, including but not limited to: the type of flow meter under test 10, the verification flow rate, the verification volume, the verification time, and the number of verifications. Preferably, the host computer mainly provides human-computer interaction, but the verification process is not static. The program can be adjusted and set as needed, such as designing different push flow rates to obtain different running programs, and then allowing the fluid push device to run according to the different programs.

[0038] Please see Figure 1 and Figure 2The system also includes a weighing unit 9 for recording the weight of the measuring container 8, and the weighing unit 9 is communicatively connected to the host computer. The weighing unit 9 can be used to record the weight changes of the measuring container 8 and send the recorded weight data to the host computer.

[0039] Please see Figure 1 and Figure 2 The fluid pushing device includes a fluid pushing unit capable of drawing in the fluid medium and then pushing it out. Further refining the fluid pushing device, it can employ a fluid pushing unit to push the fluid medium, which draws in the fluid medium and then pushes it out to the measuring container 8. Preferably, there are multiple fluid pushing units, which cooperate to form a continuous fluid pushing device that uninterruptedly pushes the fluid medium. By designing multiple fluid pushing units, uninterrupted pushing of the fluid medium can be achieved, thereby providing continuous measurement, improving measurement accuracy, and avoiding errors caused by pauses. For example, two fluid delivery units can be used in conjunction. For ease of description, they are referred to as the first fluid delivery unit 2 and the second fluid delivery unit 3, respectively. First, the first fluid delivery unit 2 extracts fluid from the fluid medium storage tank 7. At this time, the second fluid delivery unit 3 is idle. The fluid medium extracted by the first fluid delivery unit 2 is gradually delivered into the measuring container 8. During this process, the second fluid delivery unit 3 gradually extracts fluid from the fluid medium storage tank 7. After all the fluid medium in the first fluid delivery unit 2 has been delivered into the measuring container 8, the second fluid delivery unit 3 continues to gradually deliver fluid into the measuring container 8. During this process, the first fluid delivery unit 2 gradually extracts fluid from the fluid medium storage tank 7, and so on, achieving uninterrupted delivery of fluid medium. Preferably, the fluid delivery unit can be constructed using a piston, plunger, diaphragm, or similar structure, such as a syringe, to achieve both suction and delivery of fluid medium. Preferably, when the first fluid delivery unit 2 operates for the first time, the dead volume of the pipeline is deducted to ensure the accuracy of subsequent medium delivery.

[0040] Please see Figure 1 and Figure 2 The system also includes a linkage mechanism connecting the drive ends of each fluid delivery unit. The linkage mechanism can be used to connect the various fluid delivery units. For example, when a servo motor 1 is used to provide linear driving force, the linkage mechanism can be used to send the linear driving force of the servo motor 1 to each fluid delivery unit. Taking two fluid delivery units as an example... Figure 1 As shown, when the servo motor 1 pushes the first fluid pushing unit 2 to expel the air or fluid medium inside, the linkage mechanism will pull the second fluid pushing unit 3 to extract the fluid medium. Figure 1Based on this, when the servo motor 1 pushes the second fluid pushing unit 3 to push out the fluid medium inside, the linkage mechanism will pull the first fluid pushing unit 2 to extract the fluid medium. This ensures that the two sets of fluid pushing units can work together without interruption. By repeating this alternating motion, large volumes of fluid can be continuously pushed into the measuring container 8 without being limited by the volume of a single piston, greatly improving work efficiency.

[0041] Please see Figure 1 and Figure 2The system also includes a three-way valve assembly for connecting the fluid delivery device, the fluid medium storage tank 7, and the measuring container 8. When multiple flow paths are open or closed, such as when the fluid delivery device has multiple fluid delivery units, multiple three-way valves can be used to open and close different flow paths. Taking the two fluid delivery units mentioned above as an example, three three-way valves can be used to connect the flow paths. For ease of description, the three three-way valves can be defined as the first three-way valve 4, the second three-way valve 5, and the third three-way valve 6, respectively. The first fluid delivery unit 2 is connected to the first three-way valve 4, the second fluid delivery unit 3 is connected to the second three-way valve 5, the first three-way valve 4 and the second three-way valve 5 are both connected to the fluid medium storage tank 7, and the third three-way valve 6 is connected to both the first three-way valve 4 and the second three-way valve 5. Specifically, during operation, NC1 on the first three-way valve 4 is closed and NO1 is open; NC2 on the second three-way valve 5 is closed and NO2 is open; NC3 on the third three-way valve 6 is closed and NO3 is closed. The servo motor 1 drives the first fluid pushing unit 2 to retract and reset, drawing fluid from the fluid medium storage tank 7 into the first fluid pushing unit 2. Then, NC1 on the first three-way valve 4 is opened and NO1 is closed; NC2 on the second three-way valve 5 is closed and NO2 is open; NC3 on the third three-way valve 6 is closed and NO3 is open. The servo motor 1 drives the first fluid pushing unit 2 forward a short fixed distance, pushing a certain amount of fluid to the inlet of the measuring container 8. As the fluid in the measuring container 8 increases, headspace gas is squeezed out from the outlet of the measuring container 8 and reaches the flow meter 10 under test, generating a certain reading. Then, the weighing unit 9 is activated, acquiring and recording the mass m0 of the measuring container 8. The first fluid pushing unit 2 then continues pushing until the first fluid... When the pushing unit 2 is at its maximum pushing position, NC1 on the first three-way valve 4 is closed and NO1 is open, NC2 on the second three-way valve 5 is open and NO2 is closed, and NC3 on the third three-way valve 6 is open and NO3 is closed. The servo motor 1 drives the first fluid pushing unit 2 to retract and reset, and the fluid in the fluid medium storage tank 7 is drawn into the first fluid pushing unit 2. At the same time, due to the retraction of the first fluid pushing unit 2, the linkage mechanism is driven to rotate around a fixed point, which in turn drives the second fluid pushing unit 3 to continue pushing, thereby realizing the continuous flow of fluid. When the pushing and drawing speeds are set, the continuous fluid can also achieve constant speed flow throughout the process. Then, the pushed fluid flows out through the COM3 port on the third three-way valve 6 and enters the measuring container 8 placed on the weighing unit 9, causing the mass of the measuring container 8 to increase continuously. At the same time, the gas in the top space of the measuring container 8 is continuously pushed to the inlet of the flow meter 10 under test, and the flow meter 10 under test detects the flow rate / flow rate. Preferably, all the above three-way valves are solenoid valves, which can be controlled to open and close automatically by a host computer.

[0042] Please see Figure 1 and Figure 2The fluid delivery device includes a servo motor 1 for providing driving force to the fluid delivery unit. The servo motor 1 can be used to provide driving force to the fluid delivery unit, and a lead screw can be used to cooperate with the servo motor 1 to output linear driving force.

[0043] Please see Figure 1 and Figure 2 This invention provides a flow meter calibration method, which can be used in the flow meter calibration system described above. The method specifically includes the following steps: S1, storing a fluid medium in a fluid medium storage tank 7; S2, using a fluid pushing device to deliver the fluid medium from the fluid medium storage tank 7 into a measuring container 8, with headspace gas being expelled from the outlet of the measuring container 8; S3, using a flow meter under test 10 to measure the flow rate of the gas expelled from the measuring container 8; S4, obtaining the weight of the measuring container 8 before receiving the fluid medium, the weight of the measuring container 8 after receiving the fluid medium, and the volume of the gas flow measured by the flow meter under test 10; S5, calculating the difference between the weight of the measuring container 8 after receiving the fluid medium and the weight of the measuring container 8 before receiving the fluid medium, to obtain the volume of the fluid medium pushed by the fluid pushing device; S6, comparing the actual volume of the fluid medium pushed by the fluid pushing device with the volume of the gas flow measured by the flow meter under test 10 to calibrate the measurement accuracy of the flow meter under test 10. By coordinating the fluid medium storage tank 7, the measuring container 8, the fluid delivery device, the flow meter under test 10, and the host computer, the problem of automated metrological verification of different flow meters can be achieved, improving operational convenience and testing accuracy. Specifically, the fluid medium in the fluid medium storage tank 7 can be any fluid, such as pure water. The measuring container 8 is initially empty. When the fluid delivery device delivers the fluid medium into the measuring container 8, the headspace air in the measuring container 8 is expelled. This portion of the measuring container 8 can be measured by the flow meter under test 10. Finally, the host computer acquires the weight and volume data, performs calculations, and compares them to verify the measurement accuracy of the flow meter under test 10. The verification principle is that after the fluid medium is delivered into the measuring container 8, an equal volume of gas is expelled. Finally, by comparing the weight change of the measuring container 8 with the gas volume measured by the flow meter under test 10, the measurement accuracy of the flow meter under test 10 can be verified.

[0044] Please see Figure 1 and Figure 2 The fluid pushing device includes a first fluid pushing unit 2 and a second fluid pushing unit 3, which can work with a three-way valve assembly to open and close multiple flow paths, thereby achieving uninterrupted pushing operation. For details, please refer to the above embodiments, which will not be repeated here.

[0045] Please see Figure 1 and Figure 2 The difference between the weight of the measuring container 8 after receiving the fluid medium and the weight of the measuring container 8 before receiving the fluid medium is corrected to obtain the actual volume of the fluid medium pushed by the fluid pushing device. Since the density of the fluid medium is affected by temperature and pressure, its density must be corrected in real time when calculating the fluid volume. The density-temperature-pressure correction formula for the fluid medium is: Where β is the coefficient of thermal expansion of the fluid, E is the bulk modulus of elasticity of the fluid, t is the ambient temperature (degrees Celsius), and P is the ambient pressure. This represents the standard atmospheric pressure at 25°C. Ambient temperature can be obtained using a temperature sensor, and ambient pressure can be obtained using a pressure sensor. Common fluid β values ​​are: water = 0.002m. 3 / m 3 ·℃; Ethanol = 0.0011m 3 / m 3 ·℃; Common fluid E value: water = 2.15 * 10 9 (N / m 2 ); Ethanol = 1.06 * 10 9 (N / m 2 ).

[0046] Please see Figure 1 and Figure 2 The fluid pushing device includes a servo motor 1 for providing driving force. During the process of the servo motor 1 providing driving force, the servo motor 1 is calibrated in real time. The specific calibration method is as follows: the weight value of the measuring container 8 is fed back to the intermediate computer in real time, and the intermediate computer performs first-order differential processing on the weight value versus time (mt) curve. In this embodiment, when the flow meter is tested at ultra-low flow rates, the servo motor 1 will experience unstable rotational speed when moving at extremely slow speeds. Simultaneously, the driven lead screw thread has issues with movement backlash and pitch accuracy, both of which lead to speed instability and decreased position control accuracy. After prolonged operation, this will cause an increase in cumulative error, affecting the accuracy of the flow meter calibration. Therefore, real-time calibration is necessary. The weighing unit feeds back the weighing value m to the intermediate computer in real time, and the intermediate computer performs first-order differential processing on the weighing value versus time (mt) curve. When the fluid pushing device pushes the fluid, the time and mass curves should be as follows: Figure 3 The solid line shown may indicate a slope that is too large or too small when there are issues such as unstable rotational speed, backlash, or pitch accuracy in the driven leadscrew. Figure 3 As shown by the dashed line, first-order differentiation is required at this point to correct the accumulated error in order to obtain an accurate calibration result.

[0047] The following is a preferred embodiment of this flowmeter calibration method:

[0048] Step 1: Connect the inlet of the flow meter 10 to the outlet of the measuring container 8.

[0049] Step 2: Develop a calibration program using the host computer software, setting the fluid medium type and the medium density ρ. 25℃ (At 25℃), the coefficient of thermal expansion of the medium β, the bulk modulus of elasticity of the medium E, the test channel, the test flow rate / volume υ, the test volume V, the number of cycles, and the volume V of the fluid delivery unit. c Parameters such as these.

[0050] Step 3: Start the program.

[0051] Step 4: On the first three-way valve 4, NC1 is closed and NO1 is open. On the second three-way valve 5, NC2 is closed and NO2 is open. On the third three-way valve 6, NC3 is closed and NO3 is closed. The servo push system drives the first fluid push unit 2 to retract and reset, and the fluid in the fluid medium storage tank 7 is drawn into the first fluid push unit 2.

[0052] Step 5: NC1 on the first three-way valve 4 is open, and NO1 is closed. NC2 on the second three-way valve 5 is closed, and NO2 is open. NC3 on the third three-way valve 6 is closed, and NO3 is open. The servo push system drives the first fluid push unit 2 forward a short fixed distance, pushing a certain amount of fluid to the inlet of the measuring container 8. As the fluid in the measuring container 8 increases, headspace gas is squeezed out from the outlet of the measuring container 8 and flows to the flow meter under test 10. The flow meter generates a certain reading.

[0053] Step 6: Weighing unit 9 starts up, acquires and records the mass m0 of container 8 in one measurement.

[0054] Step 7: The first fluid pushing unit 2 continues to push according to the set test flow rate / flow rate υ. When the first fluid pushing unit 2 reaches its maximum pushing position, NC1 on the first three-way valve 4 closes and NO1 opens. NC2 on the second three-way valve 5 opens and NO2 closes. NC3 on the third three-way valve 6 opens and NO3 closes. The servo pushing system drives the first fluid pushing unit 2 to retract and reset, and the fluid in the fluid medium storage tank 7 is drawn into the first fluid pushing unit 2. At the same time, due to the retraction of the first fluid pushing unit 2, the linkage mechanism rotates around a fixed point, thereby driving the second fluid pushing unit 3 to continue pushing according to the set test flow rate / flow rate υ. This achieves a constant-speed, uninterrupted flow of continuous fluid.

[0055] Step 8: The pushed fluid flows out through the COM3 port on the third three-way valve 6 and enters the measuring container 8 placed on the weighing unit 9, causing the mass of the measuring container 8 to increase continuously. At the same time, the gas in the top space of the measuring container 8 is continuously pushed to the inlet of the flow meter under test 10 according to the set test flow rate / flow rate υ, so that the flow meter under test 10 detects the flow rate / flow rate.

[0056] Step 9: The first fluid delivery unit 2 and the second fluid delivery unit 3 operate continuously in a loop according to the above steps until the total delivery volume reaches the set delivery volume V, at which point operation stops. Simultaneously, the mass of the measuring container 8 will change, and the weighing unit 9 will record the second weighing mass m1. At the same time, the flow meter under test 10 measures the total flow rate V0 and sends it to the central control unit.

[0057] Step 10: The PLC sends the primary and secondary weighing data to the intermediate computer, which calculates the mass difference between the two weighings, Δm = m1 - m0.

[0058] Step 11: The PLC sends the measured ambient temperature and pressure data to the intermediate computer, which calculates the corrected density of the fluid medium using the following formula: Where β is the coefficient of thermal expansion of the fluid, E is the bulk modulus of elasticity of the fluid, t is the ambient temperature, and P is the ambient pressure. This is the standard atmospheric pressure value at 25℃.

[0059] Step 12: Using the density correction formula above, the mid-level computer calculates the actual total flow rate pushed by the first fluid push unit 2 and the second fluid push unit 3 as V1=△m / ρ.

[0060] Step 13: Compare the actual pushed volume V1 with the flow rate V0 measured by the flow meter under test 10, and calculate the single measurement error of the flow meter under test 10.

[0061] Step 14: Based on the verification program developed by the host computer software, automatically repeat steps 3 to 13 according to the different set measurement parameters.

[0062] Step 15: The intermediate computer feeds back all the above test parameters, process data, and result data to the upper computer software. The software performs relevant data statistical analysis, completes the verification and evaluation of the flow meter 10 under test, and provides results and opinions.

[0063] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for calibrating a flow meter, characterized in that, Includes the following steps: S1, fluid media are stored in a fluid media storage tank; S2, a fluid delivery device is used to deliver the fluid medium in the fluid medium storage tank into the measuring container, and the headspace gas of the measuring container is squeezed out from the outlet of the measuring container; S3, the flow rate of the gas extruded from the measuring container is measured using the flow meter under test; S4, the weight of the measuring container before receiving the fluid medium, the weight of the measuring container after receiving the fluid medium, and the flow rate and volume of the gas measured by the flow meter under test. S5, calculate the difference between the weight of the measuring container after receiving the fluid medium and the weight of the measuring container before receiving the fluid medium, so as to obtain the volume of the fluid medium pushed by the fluid pushing device; S6. The actual volume of fluid medium pushed by the fluid pushing device is compared with the gas flow rate measured by the flow meter under test to verify the measurement accuracy of the flow meter under test. The difference between the weight of the measuring container after receiving the fluid medium and the weight of the measuring container before receiving the fluid medium is corrected to obtain the actual volume of the fluid medium pushed by the fluid pushing device. The correction formula is as follows: ； Where β is the coefficient of thermal expansion of the fluid, E is the bulk modulus of elasticity of the fluid, t is the ambient temperature, and P is the ambient pressure. ρ is the standard atmospheric pressure at 25℃. 25℃ The density of the medium at 25°C; The fluid delivery device includes a first fluid delivery unit and a second fluid delivery unit. The first fluid delivery unit is used to extract fluid from the fluid medium storage tank, while the second fluid delivery unit is idle. The first fluid delivery unit gradually delivers the extracted fluid medium into the measuring container, while the second fluid delivery unit gradually extracts the fluid medium from the fluid medium storage tank. After all the fluid medium in the first fluid delivery unit has been delivered into the measuring container, the second fluid delivery unit continues to gradually deliver fluid medium into the measuring container. During this process, the first fluid delivery unit gradually extracts fluid medium from the fluid medium storage tank. This cycle is repeated to ensure uninterrupted delivery of the fluid medium.

2. The flowmeter calibration method as described in claim 1, characterized in that, The fluid pushing device includes a servo motor for providing driving force. During the process of the servo motor providing driving force, the servo motor is calibrated in real time. The specific calibration method is as follows: the weight value of the measured container is fed back to the intermediate computer in real time, and the intermediate computer performs first-order differential processing on the weight value versus time mt curve.

3. A flowmeter calibration system, characterized in that: The flow meter calibration method as described in any one of claims 1 or 2 includes a fluid medium storage tank, a measuring container, a fluid delivery device, the flow meter under test, and a host computer. The fluid medium storage tank is used to store fluid media. The measuring container is used to receive the fluid medium. The fluid delivery device is used to deliver the fluid medium into the measuring container. The flow meter under test is used to measure the flow rate of gas expelled from the measuring container after receiving the fluid medium. The host computer is used to acquire the weight of the measuring container before receiving the fluid medium, the weight of the measuring container after receiving the fluid medium, and the flow rate and volume of the gas measured by the flow meter under test, and to verify the measurement accuracy of the flow meter under test based on the acquired values.

4. The flowmeter calibration system as described in claim 3, characterized in that: It also includes a weighing unit for recording the weight of the measuring container, the weighing unit being communicatively connected to the host computer.

5. The flowmeter calibration system as described in claim 3, characterized in that: The fluid delivery device includes a fluid delivery unit capable of drawing in the fluid medium and discharging the drawn-in fluid medium.

6. The flowmeter calibration system as described in claim 5, characterized in that: The fluid delivery unit comprises multiple units, and each fluid delivery unit cooperates to form a continuous fluid delivery device that continuously delivers fluid medium.

7. The flowmeter calibration system as described in claim 6, characterized in that: It also includes a linkage mechanism connecting the drive ends of each of the fluid delivery units.

8. The flowmeter calibration system as described in claim 3, characterized in that: It also includes a three-way valve assembly for connecting the fluid delivery device, the fluid medium storage tank, and the measuring container.

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