Calibration device and calibration method for improving calibration precision of float flowmeter

Abstract

The invention belongs to the technical field of calibration and verification of shipbuilding equipment, and discloses a calibration device and a calibration method for improving the calibration precision of a float flowmeter. The problem that an existing float flowmeter is low in calibration precision is effectively solved. The calibration device comprises an intelligent comprehensive flow / pressure calibrator, a CO2 gas source and a pressure reducing valve used for adjusting the output pressure value of the CO2 gas source, an inlet of the detected float flowmeter is connected to the CO2 gas source through the pressure reducing valve, and an outlet of the detected float flowmeter is connected to the intelligent comprehensive flow / pressure calibrator. And a temperature sensor is arranged between the pressure reducing valve and the detected float flowmeter. According to the method for optimizing the calibration of the float flowmeter by increasing the real-time temperature correction coefficient, misjudgment caused by the influence of the CO2 gas temperature in an existing calibration method can be made up; by introducing the real-time temperature correction coefficient, the calibration process of the float flowmeter is optimized, and the calibration qualification rate of the float flowmeter is improved to a certain extent.

Description

Technical Field

[0001] This invention belongs to the field of calibration and verification technology of shipbuilding equipment, and particularly relates to a calibration device and calibration method for improving the calibration accuracy of a float flowmeter. Background Technology

[0002] The float flowmeter calibration device consists of a main standard instrument intelligent integrated flow / pressure calibrator 1, a CO2 gas source 2, and a pressure reducing valve 3. The calibration and verification process is based on JJG257-2007 "Verification Procedure for Float Flowmeters". The calibration environment should meet the requirements of 5~35℃, and the direct measurement method is used.

[0003] like Figure 1 As shown, the current float flowmeter calibration device consists of a main standard instrument, an intelligent integrated flow / pressure calibrator 1, a CO2 gas source 2, and a pressure reducing valve 3. The inlet of the float flowmeter 4 under test is connected to the CO2 gas source 2 via the pressure reducing valve 3, and the outlet of the float flowmeter 4 under test is connected to the intelligent integrated flow / pressure calibrator 1. The current calibration method for the float flowmeter is as follows: the inlet and outlet of the float flowmeter 4 under test are connected to the CO2 gas source 2 and the intelligent integrated flow / pressure calibrator 1, respectively. The CO2 gas source 2 is turned on, and the pressure reducing valve 3 is used to adjust the output pressure of the CO2 gas source 2 to match the working pressure of the float flowmeter 4 under test. Then, by adjusting the switch of the float flowmeter 4 under test, the forward and reverse strokes of the float flowmeter 4 under test are calibrated sequentially. The scale value of the float flowmeter 4 under test is compared with the flow rate reading on the intelligent integrated flow / pressure calibrator 1. If it does not exceed the maximum permissible error range, it is considered qualified.

[0004] During actual calibration, the laboratory maintains a constant temperature (20±5℃) year-round, meeting the environmental temperature requirements for calibration in JJG257-2007 "Verification Procedure for Float Flowmeters". However, considering the cooling characteristics of CO2, the temperature of the CO2 medium during actual calibration is lower than the 20℃ calibrated on the float flowmeter and is not constant. The CO2 temperature during calibration will have a certain impact on the outlet flow rate of the tested float flowmeter. Currently, most calibrated float flowmeters exhibit issues with calibration accuracy, even slightly exceeding the maximum permissible error. Therefore, improving the calibration accuracy of float flowmeters is of great significance. Summary of the Invention

[0005] One objective of this invention is to provide a calibration device for improving the calibration accuracy of float flowmeters, effectively solving the problem of low calibration accuracy in current float flowmeters.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a calibration device for improving the calibration accuracy of a float flowmeter, comprising an intelligent integrated flow / pressure calibrator, a CO2 gas source, and a pressure reducing valve for adjusting the output pressure value of the CO2 gas source. The inlet of the float flowmeter under test is connected to the CO2 gas source through the pressure reducing valve, and the outlet of the float flowmeter under test is connected to the intelligent integrated flow / pressure calibrator. A temperature sensor is installed between the pressure reducing valve and the float flowmeter under test.

[0007] Furthermore, the temperature sensor has a display screen that can display the detected temperature value in real time.

[0008] Another objective of this invention is to provide a calibration method for improving the calibration accuracy of a float flowmeter, applied to the apparatus for improving the calibration accuracy of a float flowmeter described in the above embodiments, comprising the following steps: First, turn on the CO2 gas source switch and control the pressure reducing valve to adjust the output pressure value of the CO2 gas source to be consistent with the working pressure of the float flowmeter under test; then, calibrate the forward and reverse strokes of the float flowmeter under test sequentially by adjusting the switch of the float flowmeter under test, while recording the temperature value detected by the temperature sensor at each calibration point to obtain the value of the real-time temperature correction coefficient; finally, correct the flow reading read on the intelligent integrated flow / pressure calibrator, and then compare it with the scale flow reading of the float flowmeter under test. If it does not exceed the maximum permissible error range, it is considered qualified.

[0009] Furthermore, the calculation method for the real-time temperature correction factor k is as follows: According to JJG257-2007 "Verification Procedure for Float Flowmeters", the flow rate calculation method using a gas float standard flowmeter as the standard is as follows:

[0010]

[0011] Where, p S p m The absolute gas pressures at the standard gas float flowmeter and the tested gas float flowmeter are T, respectively. S T m These are the gas thermodynamic temperatures at the outlets of the standard gas float flowmeter and the flowmeter under test, respectively, q SN q represents the flow rate of a standard gas float flowmeter at its calibrated flow rate. N The actual flow rate is the pressure and temperature calibrated on the float flowmeter under test.

[0012] During calibration, the standard gas float flowmeter and the float flowmeter under test are connected, and the absolute gas pressure is kept consistent, i.e., p. S =p m ,get:

[0013]

[0014] Where, q b T is the flow rate value read during the calibration process of the float flowmeter under test. a T b These are the actual measured gas thermodynamic temperature value and the gas thermodynamic temperature value calibrated by the float flowmeter, respectively. The calibrated gas thermodynamic temperature value of the float flowmeter is 293K. Therefore, a real-time temperature correction factor k is introduced:

[0015]

[0016] Compared with the prior art, the beneficial technical effects of the present invention are: (1) The present invention adds a temperature sensor that can display the real-time temperature between the pressure reducing valve of the CO2 gas source and the float flow meter under test, while keeping other components of the device unchanged; that is, the calibration device provided by the present invention has a simple and practical structure, low manufacturing cost, effectively makes up for the shortcomings of uncontrollable and unmeasurable temperature, improves the calibration accuracy of the float flow meter, optimizes the calibration process of the float flow meter, and improves the calibration pass rate of the float flow meter.

[0017] (2) This invention optimizes the calibration method of float flowmeters by adding a real-time temperature correction coefficient, which can compensate for the misjudgment caused by the influence of CO2 gas temperature in the current calibration method. According to practical experience, most of the float flowmeters currently calibrated have the phenomenon of being qualified by the wire or even slightly exceeding the maximum permissible error. By introducing a real-time temperature correction coefficient, this calibration status can be improved, the float flowmeter calibration process can be optimized, and the float flowmeter calibration pass rate can be improved to a certain extent. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the connection structure of an existing float flowmeter calibration device.

[0019] Figure 2 This is a schematic diagram of the connection structure of the float flowmeter calibration device of the present invention.

[0020] Figure labeling: Intelligent integrated flow / pressure calibrator-1; CO2 gas source-2; pressure reducing valve-3; tested float flow meter-4; temperature sensor-5; probe-6; display screen-7. Detailed Implementation

[0021] Example 1: As Figure 2As shown, the calibration device for improving the calibration accuracy of a float flowmeter provided in this embodiment includes an intelligent integrated flow / pressure calibrator 1, a CO2 gas source 2, and a pressure reducing valve 3 for adjusting the output pressure value of the CO2 gas source 2. The inlet of the float flowmeter 4 under test is connected to the CO2 gas source 2 through the pressure reducing valve 3, and the outlet of the float flowmeter 4 under test is connected to the intelligent integrated flow / pressure calibrator 1. A temperature sensor 5 that can display the real-time temperature is set between the pressure reducing valve 3 and the float flowmeter 4 under test. The temperature sensor 5 includes a probe 6 and a display screen 7.

[0022] In this embodiment, only a temperature sensor 5 that can display the real-time temperature is added between the pressure reducing valve 3 of the CO2 gas source 2 and the float flowmeter 4 under test; the other components of the device remain unchanged. The calibration device provided in this embodiment has a simple and practical structure, low manufacturing cost, and effectively compensates for the shortcomings of uncontrollable and unmeasurable temperature, thereby improving the calibration accuracy of the float flowmeter.

[0023] Based on the calibration device provided in this embodiment, the calibration method of the float flowmeter used in this embodiment is as follows: First, turn on the CO2 gas source 2 switch and control the pressure reducing valve 3 to adjust the output pressure value of the CO2 gas source 2 to be consistent with the working pressure of the float flowmeter 4 under test; then, calibrate the forward and reverse strokes of the float flowmeter 4 under test by adjusting the switch of the float flowmeter 4 under test in sequence, only at each calibration point the reading on the display screen 7 of the temperature sensor 5 needs to be recorded to obtain the value of the real-time temperature correction coefficient; finally, after correcting the flow reading read on the intelligent integrated flow / pressure calibrator 1, compare it with the scale flow reading of the float flowmeter 4 under test, and it is qualified if it does not exceed the maximum allowable error range.

[0024] In this embodiment, the real-time temperature correction coefficient k is calculated as follows: According to JJG257-2007 "Verification Procedure for Float Flowmeters", the flow rate calculation method using a gas float standard flowmeter as the standard is as follows:

[0025]

[0026] Where, p S p m The absolute gas pressures at the standard gas float flowmeter and the tested gas float flowmeter are T, respectively. S T m These are the gas thermodynamic temperatures at the outlets of the standard gas float flowmeter and the flowmeter under test, respectively, q SN q represents the flow rate of a standard gas float flowmeter at its calibrated flow rate. N The actual flow rate is the pressure and temperature calibrated on the float flowmeter under test.

[0027] During calibration, the standard gas float flowmeter and the float flowmeter under test are connected, and the absolute gas pressure is kept consistent, i.e., p. S =p m ,get:

[0028]

[0029] Where, q b T is the flow rate value read during the calibration process of the float flowmeter under test. a T b These are the actual measured gas thermodynamic temperature value and the gas thermodynamic temperature value calibrated by the float flowmeter, respectively. The calibrated gas thermodynamic temperature value of the float flowmeter is 293K. Therefore, a real-time temperature correction factor k is introduced:

[0030]

[0031] Example 1: Taking the calibration of a 5.0-grade standard working pressure of 0.10325 MPa and a range of 25 L / min as an example, the maximum permissible error is ±1.25 L / min. When calibrating the flow rate to 15 L / min, adjust the pressure reducing valve to 0.1 MPa, control the switch of the float flow meter under test, adjust the float to the 15 L / min position, and directly read the value of 13.6 L / min from the intelligent integrated flow / pressure calibrator.

[0032] When the current calibration method for float flowmeters described in the background art is used: the indication error at the 15L / min position is 13.6-15=-1.4L / min, which exceeds the maximum permissible error range and is therefore unqualified.

[0033] When using the calibration method for the float flowmeter provided in Example 1: the temperature sensor value T is read. a =263K, the real-time temperature correction factor k is calculated as follows: Therefore, the actual flow rate of the tested float flowmeter is q. N =k×q b =1.055 × 13.6 = 14.35 L / min. Therefore, the indication error at the 15 L / min position is 14.35 - 15 = -0.65 L / min, which is within the maximum permissible error range and is qualified.

[0034] This invention proposes a method to optimize the calibration of float flowmeters by adding a real-time temperature correction coefficient. This method can compensate for the misjudgments caused by the influence of CO2 gas temperature in current calibration methods. Based on practical experience, most float flowmeters currently calibrated exhibit the phenomenon of being within acceptable limits or even slightly exceeding the maximum permissible error. By introducing a real-time temperature correction coefficient, this calibration situation can be improved, the float flowmeter calibration process can be optimized, and the calibration pass rate of float flowmeters can be increased to a certain extent.

[0035] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A calibration device for improving the calibration accuracy of a float flowmeter, characterized in that, It includes an intelligent integrated flow / pressure calibrator, a CO2 gas source, and a pressure reducing valve for adjusting the output pressure value of the CO2 gas source. The inlet of the tested rotameter is connected to the CO2 gas source through the pressure reducing valve, and the outlet of the tested rotameter is connected to the intelligent integrated flow / pressure calibrator. A temperature sensor is set between the pressure reducing valve and the tested rotameter.

2. The calibration device for improving the calibration accuracy of a float flowmeter according to claim 1, characterized in that, The temperature sensor has a display screen and can display the detected temperature value in real time.

3. A calibration method for improving the calibration accuracy of a float flowmeter, characterized in that, Applied to the device for improving the calibration accuracy of the rotameter described in claim 1 or 2, it includes the following steps: First, turn on the CO2 gas source switch, and control the pressure reducing valve to adjust the output pressure value of the CO2 gas source to be consistent with the working pressure of the tested rotameter; Then, calibrate the forward and reverse strokes of the tested rotameter by adjusting the switch of the tested rotameter in sequence. At the same time, record the temperature values detected by the temperature sensor at each calibration point to obtain the value of the real-time temperature correction coefficient; Finally, after correcting the flow indication value read on the intelligent integrated flow / pressure calibrator, compare it with the calibrated flow indication value of the tested rotameter. If it does not exceed the maximum allowable error range, it is qualified.

4. The calibration method for improving the calibration accuracy of a float flowmeter according to claim 3, characterized in that, The calculation method of the real-time temperature correction coefficient k is: According to the flow calculation method using a gas float standard flowmeter as the standard in JJG 257-2007 "Verification Regulation of Rotameters": Where, p S p m The absolute gas pressures at the standard gas float flowmeter and the tested gas float flowmeter are T, respectively. S T m These are the gas thermodynamic temperatures at the outlets of the standard gas float flowmeter and the flowmeter under test, respectively, q SN q represents the flow rate of a standard gas float flowmeter at its calibrated flow rate. N The actual flow rate is the pressure and temperature calibrated on the float flowmeter under test; During calibration, the standard gas float flowmeter and the float flowmeter under test are connected, and the absolute gas pressure is kept consistent, i.e., p. S =p m ,get: Where, q b T is the flow rate value read during the calibration process of the float flowmeter under test. a T b These are the actual measured gas thermodynamic temperature value and the gas thermodynamic temperature value calibrated by the float flowmeter, respectively. The calibrated gas thermodynamic temperature value of the float flowmeter is 293K. Therefore, a real-time temperature correction factor k is introduced:

Images