A pressure sensor test calibration device and calibration method

Abstract

The application relates to the field of sensor calibration, and discloses a pressure sensor test calibration device and a calibration method, which comprise a test cavity; a gas inlet pipeline, a gas outlet pipeline, a temperature sensor, a pressure gauge and a pressure relief valve are connected to the first end of the test cavity; the gas inlet pipeline is used for feeding test gas into the test cavity and monitoring the quality of the fed test gas; the gas outlet pipeline is used for discharging the test gas in the test cavity and monitoring the quality of the discharged test gas; a plurality of to-be-calibrated pressure sensors and a standard pressure sensor are connected to the second end of the test cavity; the application obtains a calculated pressure value by feeding the discharged test gas into the test cavity, obtains a standard pressure value through the standard sensor, corrects the calculated pressure value through the standard pressure value to obtain a corrected pressure value, and then calibrates the to-be-calibrated sensor, so that the calibration precision and stability are improved.

Description

Technical Field

[0001] This invention relates to the field of sensor calibration, and in particular to a pressure sensor testing and calibration device and method. Background Technology

[0002] In the field of lasers, the gas pressure inside the laser discharge cavity has a significant impact on the laser's performance. Too low or too high gas pressure will affect the laser's power and discharge stability. Excessive gas pressure will also affect the laser's spectral characteristics and the gas's lifespan. Therefore, higher detection accuracy is required for the pressure sensor inside the laser discharge cavity.

[0003] Existing pressure sensors used in lasers generally require calibration before use. This is typically done using either the actual gas equation method or the standard pressure sensor reference method. However, both of these methods have limitations. While the actual gas equation method can accurately calculate the gas pressure within the cavity under constant temperature conditions, errors still exist in the mass of the gas introduced into the cavity during actual operation, and the mass of gas introduced in a single cycle is difficult to control. The standard pressure sensor reference method, on the other hand, requires high accuracy and reliability from the standard pressure sensor, and the standard pressure sensor still exhibits errors under different operating conditions, thus affecting the calibration accuracy of the pressure sensor. Summary of the Invention

[0004] The technical problem this invention aims to solve is: how to improve the calibration accuracy of pressure sensors. To address this problem, this invention provides a pressure sensor testing and calibration device and method, including a test chamber. The first end of the test chamber is connected to an inlet pipe, an outlet pipe, a temperature sensor, a pressure gauge, and a pressure relief valve. The inlet pipe is equipped with a first valve and a first flow meter. The first valve controls the test gas entering the test chamber, and the first flow meter monitors the mass of the test gas entering the test chamber. The outlet pipe is equipped with a second valve and a second flow meter. The second valve controls the test gas exiting the test chamber, and the second flow meter monitors the mass of the test gas exiting the test chamber. The temperature sensor detects the temperature within the test chamber, the pressure gauge monitors the gas pressure within the test chamber, and the pressure relief valve discharges the gas from the test chamber.

[0005] The second end of the test chamber is connected to multiple pressure sensors to be calibrated and at least one standard pressure sensor. The standard pressure sensor is used to detect the pressure of the test gas in the test chamber and to calibrate the pressure sensors to be calibrated.

[0006] Preferably, a first end cap is welded to the first end, and the temperature sensor and multiple socket weld tubes are provided on the side of the first end cap away from the test chamber. An adapter is provided at the other end of the socket weld tubes, and the multiple adapters are respectively connected to the first valve, the second valve, the pressure gauge and the pressure relief valve. The end of the first valve away from the first end cap is connected to the first flow meter, and the end of the second valve away from the first end cap is connected to the second flow meter.

[0007] Preferably, a second end cap is welded to the second end, and a plurality of adapter flanges are provided on the side of the second end cap away from the test chamber. The ends of the plurality of adapter flanges away from the second end cap are respectively connected to the standard pressure sensor and the pressure sensor to be calibrated; a sealing ring is provided between the adapter flange and the second end cap.

[0008] This invention also provides a pressure sensor testing and calibration method, using the pressure sensor testing and calibration device described above, comprising the following steps:

[0009] S1. Connect the intake pipe and exhaust pipe to the air source device, then open the first valve and the second valve, and use the test gas to purge the test chamber for a first preset time to remove other gases from the test chamber.

[0010] S2. Close the second valve and fully open the first valve to pressurize the gas pressure in the test chamber to a preset multiple of the target pressure. Then close the first valve and let the test chamber stand for a second preset time. If the rate of pressure drop in the test chamber during the standing period is greater than the preset rate, check the pipeline sealing and repeat step S2.

[0011] S3. Open the second valve and gradually adjust the opening of the first valve. At the same time, observe the changes of the first flow meter, the second flow meter and the pressure gauge. When the pressure gauge detects that the pressure in the test chamber is within the preset range of the target pressure, fine-tune the second valve to balance the flow and stabilize the pressure in the test chamber to the target pressure.

[0012] S4. When the pressure gauge monitors the air pressure in the test chamber and it becomes constant to the target pressure, the host computer reads the standard pressure value of the standard pressure sensor and the temperature value of the temperature sensor under the current state, and calculates the calculated pressure value under the current state through the measurement values ​​of the first flow meter and the second flow meter.

[0013] S5. Using the calculated pressure value as a reference, the calculated pressure value is corrected using the standard pressure value and temperature value to obtain the corrected pressure value.

[0014] S6. Collect the analog signal of the pressure sensor to be calibrated, and then construct a pressure-signal curve by combining the corrected pressure value;

[0015] S7. Save the data, close the first valve, and release the pressure through the pressure relief valve. When the pressure gauge reading is 0, close the entire pressure sensor test and calibration device.

[0016] Preferably, the preset multiplier is 1.2 times; the second preset time is 5 minutes; and the preset rate is 0.5% / min.

[0017] Preferably, in step S3, the opening degree of the first valve is adjusted by ≤5% each time.

[0018] Preferably, in step S4, the pressure value is calculated using the following formula:

[0019]

[0020] Where P is the calculated pressure, V is the cavity volume, R is the actual gas constant, T is the absolute temperature, n is the amount of gas, m is the gas mass, M is the molar mass, a is the intermolecular attraction correction parameter, b is the molecular volume correction parameter, and q is the molecular volume correction parameter. in q represents the intake mass flow rate monitored by the first flow meter. out The mass flow rate of the exhaust gas monitored by the second flow meter is m0, where m0 is the mass of the initial gas.

[0021] Preferably, in step S4, the calculated pressure value P is recorded at multiple target pressure points of the pressure sensor to be calibrated. 1 计算压力值 To P n 计算压力值 With the standard pressure value P 1 标准压力值 To P n 标准压力值 Furthermore, the calculated pressure values ​​of the multiple sets correspond one-to-one with the standard pressure values ​​of the multiple sets.

[0022] Preferably, in step S4, the calculated pressure value and the standard pressure value are recorded at the target pressure points of 10%, 30%, 50%, 70%, and 90% of the design range of the pressure sensor to be calibrated.

[0023] Preferably, in step S5, the following correction formula is used:

[0024] or

[0025] P 修正 =A·P 标准压力值 +B, or

[0026]

[0027] Wherein, P 修正To correct the pressure value, P 计算压力值 To calculate the pressure value, A, B, C, and D are equation coefficients, and T is the temperature value.

[0028] Compared with the prior art, the pressure sensor testing and calibration device and method provided in this embodiment of the invention have the following advantages:

[0029] In this invention, test gas is continuously introduced into the test chamber, and the calculated pressure value inside the test chamber can be calculated by combining two mass flow meters and the actual gas equation. At the same time, the standard pressure value inside the test chamber is obtained by testing with a standard pressure sensor. Subsequently, the calculated pressure value is compensated and corrected using the standard pressure value, thereby improving the calibration accuracy of the pressure sensor to be calibrated. This avoids the problem of insufficient accuracy caused by simply using the actual gas equation method to calibrate the sensor in traditional solutions, and also reduces the dependence on the reliability of the standard pressure sensor under different operating conditions. Attached Figure Description

[0030] Figure 1 This is a perspective view of the present invention;

[0031] Figure 2 This is another perspective view of the present invention;

[0032] Figure 3 This is a flowchart illustrating the present invention.

[0033] In the diagram: 1. Test chamber; 11. First end; 12. Second end; 13. First end cap; 131. Socket welded pipe; 132. Adapter; 14. Second end cap; 141. Adapter flange;

[0034] 2. Temperature sensor; 3. Pressure gauge;

[0035] 4. Inlet pipe; 41. First valve; 42. First flow meter;

[0036] 5. Exhaust pipe; 51. Second valve; 52. Second flow meter;

[0037] 6. Pressure relief valve; 7. Pressure sensor to be calibrated; 8. Standard pressure sensor. Detailed Implementation

[0038] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0039] like Figure 1 and Figure 2As shown, a preferred embodiment of the present invention provides a pressure sensor testing and calibration device and method, which includes a test chamber 1. The first end 11 of the test chamber 1 is connected to an inlet pipe 4, an exhaust pipe 5, a temperature sensor 2, a pressure gauge 3, and a pressure relief valve 6. The inlet pipe 4 is equipped with a first valve 41 and a first flow meter 42. The inlet pipe 4 is used to introduce test gas into the test chamber 1, and the first flow meter 42 is used to monitor the mass of the test gas introduced into the test chamber 1. The exhaust pipe 5 is equipped with a second valve 51 and a second flow meter 52. The exhaust pipe 5 is used to discharge the test gas from the test chamber 1, and the second flow meter 52 is used to monitor the mass of the test gas discharged from the test chamber 1. The temperature sensor 2 is used to detect the temperature inside the test chamber 1, the pressure gauge 3 is used to monitor the gas pressure state inside the test chamber 1, and the pressure relief valve 6 is used to discharge the gas inside the test chamber 1.

[0040] The second end 12 of the test chamber 1 is connected to multiple pressure sensors 7 to be calibrated and at least one standard pressure sensor 8. The standard pressure sensor 8 is used to detect the pressure of the test gas in the test chamber 1 and to calibrate the pressure sensors 7 to be calibrated.

[0041] Specifically, in traditional sensor calibration methods, the actual gas equation method is difficult to control calibration accuracy, while the standard pressure sensor method has high requirements for the accuracy and reliability of the standard pressure sensor itself. Moreover, the accuracy of the standard pressure sensor also has errors under different operating conditions, and the calibration data is greatly affected by the state of the standard pressure sensor itself. In this embodiment, an inlet pipe 4 and an exhaust pipe 5 are provided at the first end 11 of the test chamber 1. Test gas is introduced into the test chamber 1 through the inlet pipe 4 and discharged through the exhaust pipe 5. The calculated pressure value within the test chamber 1 can be obtained using a first flow meter 42 and a second flow meter 52. Simultaneously, multiple standard pressure sensors 8 and a pressure sensor 7 to be calibrated are provided at the second end 12 of the test chamber 1. Standard pressure values ​​are obtained using the standard pressure sensors 8. Then, based on the calculated pressure value, the standard pressure value is used to correct and compensate for the calculated pressure value, eliminating errors in the calculated pressure value. The corrected pressure value is then coupled with the electrical signal of the pressure sensor 7 to be calibrated, ultimately obtaining the pressure-signal curve of the pressure sensor 7 to be calibrated, achieving accurate calibration of the pressure sensor 7. Furthermore, nitrogen is used as the test gas in this embodiment. In this embodiment, the temperature value inside the test chamber 1 obtained by the temperature sensor 2 can be coupled with the data from the standard pressure sensor 8 during the calibration process, thereby eliminating the influence of temperature on the data of the standard pressure sensor 8, and thus reducing the impact of different temperatures on the calibration accuracy of the pressure sensor 7 to be calibrated, solving the problem of temperature drift in the sensor. The first valve 41 and the second valve 51 can effectively control the amount of test gas entering and exiting the test chamber 1, facilitating the acquisition and calculation of pressure values.

[0042] In some embodiments, a first end cap 13 is welded to the first end 11. A temperature sensor 2 and a plurality of socket weld tubes 131 are provided on the side of the first end cap 13 away from the test chamber 1. An adapter 132 is provided at the other end of the socket weld tubes 131. The plurality of adapters 132 are respectively connected to a first valve 41, a second valve 51, a pressure gauge 3 and a pressure relief valve 6. The end of the first valve 41 away from the first end cap 13 is connected to a first flow meter 42, and the end of the second valve 51 away from the first end cap 13 is connected to a second flow meter 52.

[0043] Furthermore, a second end cap 14 is welded to the second end 12. Multiple transition flanges 141 are provided on the side of the second end cap 14 away from the test chamber 1. The ends of the multiple transition flanges 141 away from the second end cap 14 are respectively connected to the standard pressure sensor 8 and the pressure sensor 7 to be calibrated. A sealing ring is provided between the transition flange 141 and the second end cap 14.

[0044] Specifically, in this embodiment, the first end cap 13 and the second end cap 14 are fixed at both ends of the test chamber 1 by argon arc welding, thereby ensuring the integrity and airtightness of the entire test chamber 1. Subsequently, the temperature sensor 2 is installed in the middle of the first end cap 13 by a screw hole, and a circular groove is also provided for installing the socket weld tube 131. The end of the temperature sensor 2 and the end of the socket weld tube 131 closest to the test chamber 1 are both inserted into the test chamber 1 and communicate with the space inside the test chamber 1. The end of the socket weld tube 131 away from the test chamber 1 is provided with a VCR adapter 132. Multiple different socket weld tubes 131 are connected to the pressure gauge 3, the pressure relief valve 6, the first valve 41, and the second valve 51 respectively through the VCR adapter 132. The VCR adapter 132 can ensure the airtightness and stability of the connection and ensure the accuracy of various data during the calibration process. The end of the second end cap 14 away from the test chamber 1 is fixed with multiple transition flanges 141 by screws. A nitrile rubber ring is set between the transition flange 141 and the second end cap 14 as a sealing ring, which can achieve the sealing effect and prevent gas from leaking out of the test chamber 1.

[0045] like Figure 3 As shown, the present invention also provides a pressure sensor testing and calibration method, which uses the pressure sensor testing and calibration device described above, and includes the following steps:

[0046] S1. Connect the intake pipe 4 and the exhaust pipe 5 to the air source device, then open the first valve 41 and the second valve 51, and use the test gas to purge the test chamber 1 for a first preset time to remove other gases in the test chamber 1.

[0047] S2. Close the second valve 51 and fully open the first valve 41 to pressurize the gas pressure in the test chamber 1 to a preset multiple of the target pressure. Then close the first valve 41 and let the test chamber 1 stand for a second preset time. If the rate of pressure drop in the test chamber 1 during the standing process is greater than the preset rate, check the pipeline sealing and repeat step S2.

[0048] S3. Open the second valve 51 and gradually adjust the opening of the first valve 41. At the same time, observe the changes of the first flow meter 42, the second flow meter 52 and the pressure gauge 3. When the pressure gauge 3 detects that the pressure in the test chamber 1 is close to the target pressure and within the preset range of the target pressure, fine-tune the second valve 51 to balance the flow and stabilize the pressure in the test chamber 1 to the target pressure.

[0049] S4. When the pressure gauge 3 monitors the air pressure in the test chamber 1 and it becomes constant to the target pressure, the host computer reads the standard pressure value of the standard pressure sensor 8 and the temperature value of the temperature sensor 2 under the current state, and calculates the calculated pressure value under the current state through the measurement values ​​of the first flow meter 42 and the second flow meter 52.

[0050] S5. Using the calculated pressure value as a reference, the calculated pressure value is corrected using the standard pressure value and temperature value to obtain the corrected pressure value.

[0051] S6. Collect the analog signal of the pressure sensor 7 to be calibrated, and then construct a pressure-signal curve by combining the corrected pressure value;

[0052] S7. Save the data, close the first valve 41, and release the pressure through the pressure relief valve 6. When the reading of the pressure gauge 3 is 0, close the entire pressure sensor test and calibration device.

[0053] Specifically, in this embodiment, the first valve 41, the second valve 51, the first flow meter 42, the second flow meter 52, the pressure gauge 3, the temperature sensor 2, and multiple standard pressure sensors 8 and multiple pressure sensors 7 to be calibrated are first assembled on the test chamber 1. At the same time, each valve, flow meter, and sensor is connected to the power supply equipment, the air supply equipment, and the control equipment. Then, the main power is turned on, the control software is started, and the main switch of the air supply equipment is slowly opened. It is observed whether the pressure gauge 3 is stable within the preset range, thereby testing whether each component is working properly and completing the self-test of the entire device.

[0054] Then, the first valve 41 on the inlet pipe 4 and the second valve 51 on the exhaust pipe 5 can be opened to introduce nitrogen into the test chamber 1. The nitrogen is used to flush the test chamber 1, removing any remaining gases and ensuring the accuracy of the calculated pressure values ​​obtained from the inlet and outlet flow rates of the test chamber 1. This avoids adverse effects from other impurities on the calculated pressure values. The nitrogen introduction rate and the preset introduction time can be adjusted adaptively according to the actual size of the test chamber 1. When the test chamber 1 is large, the nitrogen flushing rate and flushing time should be increased accordingly to remove as many other gases as possible from the test chamber 1, minimizing the impact of these gases on subsequent data acquisition.

[0055] After the test chamber 1 has finished rinsing, the airtightness of the entire device needs to be checked. Problems with the airtightness of the entire device will seriously affect the accuracy of the calibration data for the pressure sensor 7 to be calibrated. Therefore, the airtightness of the entire device needs to be checked before each calibration. In this embodiment, the pressure inside the test chamber 1 is increased to several times the target pressure by fully opening the first valve 41. Then, the first valve 41 is closed, and the airtightness of the entire test device is judged by observing the rate of pressure drop inside the test chamber 1. When the rate of pressure drop inside the test chamber 1 is too fast, exceeding the preset rate, it indicates that the airtightness of the entire device is poor and there is a leak. It is not suitable for calibrating the pressure sensor 7 to be calibrated. At this time, the connection status of the entire device needs to be adjusted, and the airtightness of the entire device needs to be checked again to ensure that the device meets the requirements for subsequent use. The preset multiplier is preferably 1.2 times, the second preset time is preferably 5 minutes, and the preset rate is set at 0.5% / min.

[0056] After the entire device passes the airtightness check, calibration can begin. After opening the second valve 51 to facilitate gas venting, gradually adjust the opening of the first valve 41, and continuously observe the pressure within the test chamber 1 using pressure gauge 3. Adjust the first valve 41 and the second valve 51 to regulate the air intake and exhaust rates within the test chamber 1, bringing the pressure within the test chamber 1 close to the target pressure. Then, fine-tune the second valve 51 to stabilize the pressure within the test chamber 1 at the target pressure. Preferably, the adjustment of the opening of the first valve 41 should be maintained below 5% each time. Excessive adjustment in a single step can easily cause instability in the internal air pressure of the test chamber 1, affecting the stable reading of various data.

[0057] Once the pressure inside test chamber 1 stabilizes, the host computer can read the temperature value detected by temperature sensor 2 and the standard pressure value detected by standard pressure sensor 8. If multiple standard pressure sensors 8 are set, the values ​​detected by these sensors can be averaged, and the averaged data can be used as the standard pressure value for the current state. Simultaneously, the inlet flow rate monitored by the first flow meter 42 and the outlet flow rate monitored by the second flow meter 52 need to be acquired, and the calculated pressure value for the current state can be obtained using the actual gas equation. Finally, using the calculated pressure value as a benchmark, the calculated pressure value is corrected using the standard pressure value and temperature value to obtain the corrected pressure value. This corrected pressure value can then be used as the pressure value of the pressure sensor 7 to be calibrated. By using the corrected pressure value and the analog signal of the pressure sensor 7 to be calibrated, a pressure-signal curve for the pressure sensor 7 can be constructed, thus completing the calibration of the pressure sensor 7. Compared to the traditional method of calibrating pressure sensors by measuring air intake and exhaust volume, the calibration data in this embodiment is undoubtedly more accurate. Furthermore, the more data from the standard pressure sensors 8, the smaller the calibration error, improving the accuracy of the calibration data and eliminating the problem of insufficient reliability of a single standard pressure sensor 8. In practice, during formal measurements, the data from multiple standard pressure sensors 8 can be filtered. For example, the highest and lowest values ​​can be removed, followed by averaging. Alternatively, if the value deviation of a certain standard pressure sensor 8 is too large, exceeding a preset value, that standard pressure sensor 8 can be considered unreliable and its data removed, thereby further improving the accuracy of the calibration data.

[0058] In some embodiments, the pressure value in step S4 is calculated using the following formula:

[0059]

[0060] Where P is the calculated pressure, V is the cavity volume, R is the actual gas constant, T is the absolute temperature, n is the amount of gas, m is the gas mass, M is the molar mass, a is the intermolecular attraction correction parameter, b is the molecular volume correction parameter, and q is the molecular volume correction parameter. in q is the inlet mass flow rate monitored by the first flow meter 42. out The exhaust mass flow rate is monitored by the second flow meter 52, and m0 is the initial gas mass (usually 0).

[0061] in,

[0062] Specifically, in this embodiment, considering that the pressure range inside the test chamber 1 is 0MPa-10MPa, the actual gas equation of state is used for more accurate expression in actual operation. The actual gas equation of state is as follows:

[0063]

[0064] The relationship between gas mass m and time t is as follows:

[0065] Where q in (t)-q out (t) represents the dynamic net flow rate. Combining it with the actual gas law, we can obtain the relationship between P and the dynamic net flow rate.

[0066] Assuming the introduced gas is nitrogen at a constant flow rate, the container volume is 0.003 cubic meters, T = 298 kJ, M = 0.028 kg / mol, a = 0.137, b = 0.0000387, R = 8.314, qin = 0.005 kg / s, and qout = 0.002 kg / s, with a target pressure of 10 MPa, the following results are obtained by substituting the values ​​into the equations:

[0067] At 50s, P = 5.12MPa; at 100s, P = 8.62MPa; and at 117.6s, it can reach 10MPa. Therefore, this method can be used to achieve a specific pressure value by controlling the flow rate and the gas introduction time.

[0068] In some embodiments, in step S4, the calculated pressure value P is recorded at multiple target pressure points of the pressure sensor 7 to be calibrated. 1 计算压力值 To P n 计算压力值 Compared with standard pressure value P 1 标准压力值 To P n 标准压力值 Furthermore, multiple sets of calculated pressure values ​​correspond one-to-one with multiple sets of standard pressure values.

[0069] Furthermore, in step S4, the calculated pressure value and the standard pressure value are recorded at pressure points at 10%, 30%, 50%, 70%, and 90% of the design range of the pressure sensor 7 to be calibrated.

[0070] Specifically, single data points often contain errors. In actual operation, multiple sets of calculated and target pressure values ​​need to be recorded, covering multiple target pressure points within the range of the pressure sensor 7 to be calibrated, thereby minimizing the adverse effects of errors. In this embodiment, five sets of data are recorded at 10%, 30%, 50%, 70%, and 90% of the designed range of the pressure sensor 7 to be calibrated. Each set of data includes the corresponding calculated pressure value, standard pressure value, and temperature value. Furthermore, different temperatures can be set for the test chamber 1 at different target pressure points to eliminate the influence of temperature, making the corrected pressure value more accurate and reliable.

[0071] In some embodiments, the following correction formula is used in step S5:

[0072] or

[0073] P 修正 =A·P 标准压力值 +B, or

[0074]

[0075] Among them, P 修正 To correct the pressure value, P 计算压力值 To calculate the pressure value, A, B, C, and D are equation coefficients, and T is the temperature value.

[0076] Specifically, in this embodiment, three correction formulas are provided. In actual operation, the formula can be selected based on the characteristic curves of different sensors. When the characteristic curve of the pressure sensor 7 to be calibrated is linear, then P is selected. 修正 =A·P 标准压力值 +B; When the characteristic curve of the pressure sensor 7 to be calibrated is nonlinear, two other correction formulas are selected. Furthermore, the coefficients of equations A, B, C, and D are obtained based on multiple sets of calculated pressure values, multiple sets of standard pressure values, and temperature values.

[0077] In one specific embodiment, the following data is available:

[0078] P 标准压力值 =[9.874,9.998,10.156,10.739,11.15]kPa;

[0079] P 计算压力值 =[10.145,10.322,10.614,11.152,11.432]kPa;

[0080] T = [20, 30, 40, 50, 60];

[0081] The formula used is: First, construct the data matrix:

[0082]

[0083] Construct the target vector:

[0084]

[0085] Coefficient vector of the system of equations:

[0086]

[0087] Subsequently, the coefficients are solved using the least squares method: β=(X T X) -1 X T y;

[0088] The solved coefficients are: A = -0.002312, B = 0.662714, C = 0.012846, D = 3.891045; therefore, the compensation formula is: If the measured value is P 标准压力值 =10.5kPa, T=45℃, then P 修正 =10.78 kPa;

[0089] In summary, the embodiments of the present invention provide a pressure sensor testing and calibration device and method. It obtains the calculated pressure value within the test chamber 1 using a first flow meter 42 and a second flow meter 52, while simultaneously obtaining standard pressure values ​​using multiple standard pressure sensors 8. Then, using the calculated pressure value as a reference, the calculated pressure value is calibrated using the standard pressure values ​​to obtain a more accurate corrected pressure value. By combining the corrected pressure value with the analog signal of the pressure sensor 7 to be calibrated, the calibration of the pressure sensor 7 is finally completed. This reduces the problems of excessive calibration error and low calibration accuracy in traditional solutions, and also reduces the dependence on the reliability of the standard pressure sensors 8 during the calibration process, making the calibration of the pressure sensor 7 to be calibrated more accurate and stable.

[0090] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several improvements and substitutions without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A pressure sensor testing and calibration device, characterized in that, The device includes a test chamber, with an inlet pipe, an outlet pipe, a temperature sensor, a pressure gauge, and a pressure relief valve connected to its first end. The inlet pipe is equipped with a first valve and a first flow meter. The first valve controls the amount of test gas introduced into the test chamber, and the first flow meter monitors the mass of the test gas introduced into the test chamber. The outlet pipe is equipped with a second valve and a second flow meter. The second valve controls the discharge of test gas from the test chamber, and the second flow meter monitors the mass of the discharged test gas. The temperature sensor detects the temperature within the test chamber, the pressure gauge monitors the gas pressure within the test chamber, and the pressure relief valve discharges gas from the test chamber. The second end of the test chamber is connected to multiple pressure sensors to be calibrated and at least one standard pressure sensor. The standard pressure sensor is used to detect the pressure of the test gas in the test chamber and to calibrate the pressure sensors to be calibrated.

2. The pressure sensor testing and calibration device according to claim 1, characterized in that, The first end is welded with a first end cap. The temperature sensor and multiple socket weld tubes are arranged on the side of the first end cap away from the test chamber. The other end of the socket weld tubes is provided with an adapter. The multiple adapters are respectively connected to the first valve, the second valve, the pressure gauge and the pressure relief valve. The end of the first valve away from the first end cap is connected to the first flow meter. The end of the second valve away from the first end cap is connected to the second flow meter.

3. The pressure sensor testing and calibration device according to claim 1, characterized in that, The second end is welded with a second end cap, and multiple adapter flanges are provided on the side of the second end cap away from the test chamber. The ends of the multiple adapter flanges away from the second end cap are respectively connected to the standard pressure sensor and the pressure sensor to be calibrated; a sealing ring is provided between the adapter flange and the second end cap.

4. A method for testing and calibrating a pressure sensor, using the pressure sensor testing and calibration apparatus as described in any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Connect the intake pipe and exhaust pipe to the air source device, then open the first valve and the second valve, and use the test gas to purge the test chamber for a first preset time to remove other gases from the test chamber. S2. Close the second valve and fully open the first valve to pressurize the gas pressure in the test chamber to a preset multiple of the target pressure. Then close the first valve and let the test chamber stand for a second preset time. If the rate of pressure drop in the test chamber during the standing period is greater than the preset rate, check the pipeline sealing and repeat the step. S3. Open the second valve and gradually adjust the opening of the first valve. At the same time, observe the changes of the first flow meter, the second flow meter and the pressure gauge. When the pressure gauge detects that the pressure in the test chamber is within the preset range of the target pressure, fine-tune the second valve to balance the flow and stabilize the pressure in the test chamber to the target pressure. S4. When the pressure gauge monitors the air pressure in the test chamber and it becomes constant to the target pressure, the host computer reads the standard pressure value of the standard pressure sensor and the temperature value of the temperature sensor under the current state, and calculates the calculated pressure value under the current state through the measurement values ​​of the first flow meter and the second flow meter. S5. Using the calculated pressure value as a reference, the calculated pressure value is corrected using the standard pressure value and temperature value to obtain the corrected pressure value. S6. Collect the analog signal of the pressure sensor to be calibrated, and then construct a pressure-signal curve by combining the corrected pressure value; S7. Save the data, close the first valve, and release the pressure through the pressure relief valve. When the pressure gauge reading is 0, close the entire pressure sensor test and calibration device.

5. The pressure sensor testing and calibration method according to claim 4, characterized in that, The preset multiplier is 1.2 times; the second preset time is 5 minutes; and the preset rate is 0.5% / min.

6. The pressure sensor testing and calibration method according to claim 4, characterized in that, In step S3, the opening degree of the first valve is adjusted by ≤5% each time.

7. The pressure sensor testing and calibration method according to claim 4, characterized in that, In step S4, the pressure value is calculated using the following formula: Where P is the calculated pressure, V is the cavity volume, R is the actual gas constant, T is the absolute temperature, n is the amount of gas, m is the gas mass (approximated by the ideal gas law), M is the molar mass, a is the intermolecular attraction correction parameter, b is the molecular volume correction parameter, and q... in q represents the intake mass flow rate monitored by the first flow meter. out The mass flow rate of the exhaust gas monitored by the second flow meter is m0, where m0 is the mass of the initial gas.

8. The pressure sensor testing and calibration method according to claim 4, characterized in that, In step S4, the calculated pressure value P is recorded at multiple target pressure points of the pressure sensor to be calibrated. 1 计算压力值 To P n 计算压力值 Compared with standard pressure value P 1 标准压力值 To P n 标准压力值 Furthermore, multiple sets of calculated pressure values ​​correspond one-to-one with multiple sets of standard pressure values.

9. The pressure sensor testing and calibration method according to claim 8, characterized in that, In step S4, at the target pressure points of 10%, 30%, 50%, 70%, and 90% of the design range of the pressure sensor to be calibrated, the corresponding calculated pressure value and standard pressure value are recorded respectively.

10. The pressure sensor testing and calibration method according to claim 8, characterized in that, In step S5, the following correction formula is used: or P 修正 =A·P 标准压力值 +B, or Among them, P 修正 To correct the pressure value, P 计算压力值 To calculate the pressure value, A, B, C, and D are equation coefficients, and T is the temperature value.

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