Online calibration method for pressure measurement system in pressure test bench

Abstract

The invention discloses an online calibration method for a pressure measurement system in a pressure test bench, and the method comprises the steps: selecting a standard device matched with the pressure measurement system according to the parameter information of the pressure measurement system; connecting the selected standard device with a pressure test bench; the pressure field calibrator is connected with the standard device through a special connecting line, and the pressure test bench and the pressure field calibrator are controlled to be started for preheating; starting pressure measurement according to the selected pressure calibration point, and reading and recording a measurement result; and completing online calibration of the pressure measurement system according to the recorded measurement result. According to the online calibration method, the consistency of the calibration environment and the actual working environment of the pressure measurement system can be ensured, errors caused by height difference are effectively reduced, and data processing is simple and convenient.

Description

Technical Field

[0001] The invention belongs to the field of metrology science and technology, and in particular relates to an online calibration method for a pressure measurement system in a pressure test bench. Background Art

[0002] At present, the pressure transmitters used in pressure test benches must be disassembled and sent to the metrology laboratory for calibration and verification every year. Disassembly leads to problems and hidden dangers such as interface damage, loose sealing, wrong range connection, production line shutdown and delay of production cycle. Moreover, the qualified individual calibration of pressure transmitters and display instruments cannot guarantee that the metrological performance of the entire pressure measurement system meets the process parameter requirements. For the above reasons, there is an urgent need for a new calibration method that can solve the online calibration of the pressure measurement system in the pressure test bench and provide a technical reference for the metrological reliability of various pressure tests. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and to provide an online calibration method for a pressure measurement system in a pressure test bench, which can ensure the consistency between the calibration environment of the pressure measurement system and the actual working environment, effectively reduce the error introduced by the height difference, and make data processing simple and convenient.

[0004] In order to solve the above technical problems, the present invention discloses an online calibration method for a pressure measurement system in a pressure test bench, comprising:

[0005] According to the parameter information of the pressure measurement system, select a standard device that matches the pressure measurement system;

[0006] Connect the selected standard to the pressure test bench;

[0007] Connect the pressure field calibrator to the standard instrument through a dedicated connection line to control the pressure test bench and the pressure field calibrator to start and preheat;

[0008] According to the selected pressure calibration point, start pressure measurement, read and record the measurement results;

[0009] Based on the recorded measurement results, an online calibration of the pressure measurement system is completed.

[0010] In the above-mentioned online calibration method for the pressure measurement system in the pressure test bench, the pressure test bench includes: a pressure measurement system and a pressure pipeline; wherein the pressure measurement system and the pressure pipeline are installed on the pressure test bench.

[0011] In the above-mentioned online calibration method for the pressure measurement system in the pressure test bench, the pressure measurement system includes: a display instrument and a pressure transmitter; wherein the pressure transmitter is connected to the pressure pipeline; and the display instrument is connected to the pressure transmitter via a dedicated connecting line.

[0012] In the above-mentioned online calibration method for the pressure measurement system in the pressure test bench, a standard matching the pressure measurement system is selected according to the parameter information of the pressure measurement system, including: determining the measuring range and accuracy grade of the pressure transmitter; and selecting a standard matching the measuring range and accuracy grade of the pressure transmitter.

[0013] In the above-mentioned online calibration method for the pressure measurement system in the pressure test bench, the selected standard is connected to the pressure test bench, including: installing the selected standard that matches the range and accuracy level of the pressure transmitter at the outlet position of the pressure pipeline.

[0014] In the above-mentioned online calibration method for the pressure measurement system in the pressure test bench, pressure measurement is started according to the selected pressure calibration point, and the measurement results are read and recorded, including:

[0015] Determine the upper and lower pressure limits according to the measuring range of the pressure transmitter;

[0016] Based on the upper pressure limit and the lower pressure limit, several pressure calibration points are selected;

[0017] The pressure is adjusted step by step, starting from the lower pressure limit value and steadily increasing to each pressure calibration point until the upper pressure limit value; then the pressure is adjusted step by step in the opposite direction, starting from the upper pressure limit value and steadily decreasing to each pressure calibration point until the lower pressure limit value; this is recorded as one cycle;

[0018] Perform at least 3 cycles continuously, and read and record the output value A of the standard at each pressure calibration point during each cycle. i,j And the display value of the display instrument C i,j ; Wherein, i represents the number of cycles, i≥3; j represents the sequence number of the pressure calibration point, j≥3.

[0019] In the above-mentioned online calibration method for the pressure measurement system in the pressure test bench, the online calibration of the pressure measurement system is completed according to the recorded measurement results, including:

[0020] According to the output value A of the standard under each pressure calibration point in each cycle i,j And the display value of the display instrument C i,j , combined with the set value B of the pressure measurement system i,j , calculate the indication error Δ of the pressure measurement system i,j , repeatability s of indication error and control deviation t;

[0021] According to the indication error Δ i,j , repeatability of indication error s and control deviation t, to determine whether the pressure measurement system meets the technical indicators.

[0022] In the above-mentioned online calibration method for the pressure measurement system in the pressure test bench, when the pressure transmission medium is liquid, if the reference plane of the pressure port of the standard instrument and the reference plane of the pressure port of the pressure transmitter are not on the same horizontal plane, a steel ruler is used to determine the height difference h for correction.

[0023] The above-mentioned online calibration method for the pressure measurement system in the pressure test bench also includes: using a thermometer and a hygrometer to record the ambient temperature and humidity, and the ambient temperature and humidity meet the use requirements of the pressure measurement system.

[0024] The above-mentioned online calibration method for the pressure measurement system in the pressure test bench also includes: before performing the online calibration, checking the overall status of the pressure test bench and the pressure measurement system.

[0025] The present invention has the following advantages:

[0026] The invention discloses an online calibration method for a pressure measurement system in a pressure test bench, which can ensure the consistency between the calibration environment of the pressure measurement system and the actual working environment, effectively reduce the error introduced by the height difference, and the data processing is simple and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a structural schematic diagram of an online calibration device in an embodiment of the present invention;

[0028] Figure 2 The present invention is a flowchart of an online calibration method for a pressure measurement system in a pressure test bench according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0030] One of the core ideas of the present invention is to provide an online calibration method that can realize online calibration of the pressure measurement system in the pressure test bench. The online calibration method is based on Figure 1 The online calibration device shown is implemented. Figure 1As shown, the online calibration device mainly includes: a standard instrument 1, a field calibrator 2, a steel ruler 3, a thermometer 4 and a hygrometer 5. The pressure test bench 10 mainly includes: a pressure measurement system 100, a pressure pipeline 200 and other parameter systems, and the pressure measurement system 100, the pressure pipeline 200 and other parameter systems are all installed on the pressure test bench 10. Further, the pressure measurement system 100 mainly includes: a display instrument 101 and a pressure transmitter 102, the pressure transmitter 102 is connected to the pressure pipeline 200, and the display instrument 101 is connected to the pressure transmitter 102 through a dedicated connecting line.

[0031] In this embodiment, if Figure 2 As shown, the online calibration method for the pressure measurement system in the pressure test bench comprises:

[0032] Step 1: Select a standard device 1 that matches the pressure measurement system 100 according to parameter information of the pressure measurement system 100 .

[0033] In this embodiment, the measuring range and accuracy level of the pressure transmitter 102 are first determined; then, a standard 1 matching the measuring range and accuracy level of the pressure transmitter 102 is selected. The standard is usually a pressure module or a digital pressure gauge, etc., and the measuring range should be greater than or equal to the measuring range of the pressure transmitter; the expanded uncertainty introduced by the combination of the standard and the pressure field calibrator should not be greater than 1 / 4 of the absolute value of the maximum allowable error of the pressure transmitter.

[0034] Step 2, connecting the selected standard device 1 to the pressure test bench 10.

[0035] In this embodiment, the standard instrument 1 selected to match the measuring range and accuracy level of the pressure transmitter 102 is installed at the outlet of the pressure pipeline 200. When the pressure transmission medium is liquid, the reference plane of the pressure port of the standard instrument 1 should be on the same horizontal plane as the reference plane of the pressure port of the pressure transmitter 102.

[0036] When the pressure transmission medium is liquid, if the reference plane of the pressure port of the standard device 1 and the reference plane of the pressure port of the pressure transmitter 102 are not in the same horizontal plane, the steel ruler 3 can be used to determine the working position height difference h between the standard device and the pressure transmitter; if h is not greater than the height difference threshold h0 calculated by the following formula 1, the error caused by the reference plane of the pressure port of the standard device and the reference plane of the pressure port of the pressure transmitter not being in the same horizontal plane can be ignored; if h is greater than the height difference threshold h0, it is corrected by the following formula 2:

[0037]

[0038] ΔP=±ρgh···(2)

[0039] Where a% represents the percentage of the accuracy grade of the pressure transmitter, ΔP represents the pressure compensation value, P m It represents the input range of the pressure transmitter, ρ represents the density of the pressure medium, and g represents the local gravity acceleration.

[0040] Step 3, connect the pressure field calibrator 2 to the standard device 1 through a dedicated connection line, and control the pressure test bench 10 and the pressure field calibrator 2 to start up and preheat.

[0041] In this embodiment, the pressure field calibrator 2 is small in size and light in weight, and is easy to carry to the site for calibration. The field pressure calibrator integrates the functions of AC and DC voltage regulators and DC current and voltage meters; the field pressure calibrator of level 0.02 and above is selected for high precision to ensure the reliability of field calibration. Use a dedicated connecting line to connect the standard device and the field pressure calibrator, and select the corresponding test gear of the field pressure calibrator. The pressure test bench 10 and the pressure field calibrator 2 are turned on and preheated, and the preheating time is usually not less than 15 minutes. At the same time, the thermometer 4 and the hygrometer 5 can be used to record the ambient temperature and humidity to ensure that the ambient temperature and humidity meet the use requirements of the pressure measurement system 100.

[0042] Step 4: Start pressure measurement based on the selected pressure calibration point, and read and record the measurement results.

[0043] In this embodiment, the specific implementation process of step 5 is as follows:

[0044] According to the measuring range of the pressure transmitter 102, the upper pressure limit value and the lower pressure limit value are determined; based on the upper pressure limit value and the lower pressure limit value.

[0045] Select several pressure calibration points. The selected pressure calibration points should generally include at least 3 points including the upper pressure limit and the lower pressure limit (or within 10% of the input range nearby); for pressure test benches that cannot achieve pressure rise and fall, one pressure point calibration can be performed at the pressure point where the pressure measurement system works.

[0046] The pressure is adjusted step by step, starting from the lower pressure limit and steadily increasing to each pressure calibration point until the upper pressure limit; then the pressure is adjusted step by step in the opposite direction, starting from the upper pressure limit and steadily decreasing to each pressure calibration point until the lower pressure limit; this is recorded as one cycle.

[0047] Perform at least 3 cycles continuously, and read and record the output value A of the standard 1 under each pressure calibration point during each cycle. i,j and the display value C of the display instrument 101 i,j .

[0048] Wherein, i represents the number of cycles, i≥3, i.e., no less than 3 cycles; j represents the number of pressure calibration points, j≥3, i.e., no less than 3 pressure calibration points. For a pressure test bench that can achieve pressure rise and fall, the pressure change inside the pressure pipeline when the pressure test bench is working normally is used as the pressure source.

[0049] Step 5: Complete the online calibration of the pressure measurement system 100 according to the recorded measurement results.

[0050] In this embodiment, the output value A of the standard device 1 under each pressure calibration point condition in each cycle can be recorded. i,j and the display value C of the display instrument 101 i,j , combined with the set value B of the pressure measurement system 100 i,j , calculate the indication error Δ of the pressure measurement system i,j , repeatability of indication error s and control deviation t; further, according to the indication error Δ i,j , the repeatability s of the indication error and the control deviation t are used to comprehensively determine whether the pressure measurement system 100 meets the technical indicators.

[0051] Preferably, the indication error Δ i,j , the calculation formulas for the repeatability s of the indication error and the control deviation t are as follows:

[0052] Δ i,j =C i,j -A i,j ···(3)

[0053]

[0054] t=A i,j -B i,j ···(5)

[0055] in, Indicates the average value of the indication error.

[0056] In an embodiment of the present invention, the online calibration method for the pressure measurement system in the pressure test bench also includes: before performing the online calibration, checking the overall status of the pressure test bench 10 and the pressure measurement system 100, including but not limited to: whether the appearance is intact, whether each component is operating normally, etc.

[0057] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

[0058] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. An online calibration method for a pressure measurement system in a pressure test bench, characterized in that: include: Selecting a standard device (1) matching the pressure measurement system (100) according to parameter information of the pressure measurement system (100); Connecting the selected standard device (1) to the pressure test bench (10); The pressure field calibrator (2) is connected to the standard device (1) via a dedicated connection line, and the pressure test bench (10) and the pressure field calibrator (2) are controlled to start and preheat; According to the selected pressure calibration point, start pressure measurement, read and record the measurement results; Based on the recorded measurement results, the online calibration of the pressure measurement system (100) is completed.

2. The online calibration method for a pressure measurement system in a pressure test bench according to claim 1, characterized in that: A pressure test bench (10) comprises: a pressure measurement system (100) and a pressure pipeline (200); wherein the pressure measurement system (100) and the pressure pipeline (200) are installed on the pressure test bench (10).

3. The online calibration method for the pressure measurement system in the pressure test bench according to claim 2, characterized in that: A pressure measurement system (100) comprises: a display instrument (101) and a pressure transmitter (102); wherein the pressure transmitter (102) is connected to a pressure pipeline (200); and the display instrument (101) is connected to the pressure transmitter (102) via a dedicated connection line.

4. The online calibration method for a pressure measurement system in a pressure test bench according to claim 3, characterized in that: According to parameter information of the pressure measurement system (100), a standard device (1) matching the pressure measurement system (100) is selected, including: determining the measuring range and accuracy level of the pressure transmitter (102); and selecting the standard device (1) matching the measuring range and accuracy level of the pressure transmitter (102).

5. The online calibration method for the pressure measurement system in the pressure test bench according to claim 4, characterized in that: Connecting the selected standard device (1) to the pressure test bench (10) includes: installing the selected standard device (1) matching the measuring range and accuracy level of the pressure transmitter (102) at the outlet position of the pressure pipeline (200).

6. The online calibration method for a pressure measurement system in a pressure test bench according to claim 5, characterized in that: According to the selected pressure calibration point, start pressure measurement, read and record the measurement results, including: Determining an upper pressure limit and a lower pressure limit according to a measuring range of a pressure transmitter (102); Based on the upper pressure limit and the lower pressure limit, several pressure calibration points are selected; The pressure is adjusted step by step, starting from the lower pressure limit value and steadily increasing to each pressure calibration point until the upper pressure limit value; then the pressure is adjusted step by step in the opposite direction, starting from the upper pressure limit value and steadily decreasing to each pressure calibration point until the lower pressure limit value; this is recorded as one cycle; Perform at least 3 cycles continuously, and read and record the output value A of the standard instrument (1) at each pressure calibration point during each cycle. i,j and the display value C of the display instrument (101) i,j ; Wherein, i represents the number of cycles, i≥3; j represents the sequence number of the pressure calibration point, j≥3.

7. The online calibration method for a pressure measurement system in a pressure test bench according to claim 6, characterized in that: According to the recorded measurement results, the online calibration of the pressure measurement system (100) is completed, including: According to the output value A of the standard device (1) under each pressure calibration point in each cycle, i,j and the display value C of the display instrument (101) i,j , combined with the set value B of the pressure measurement system (100) i,j , calculate the indication error Δ of the pressure measurement system i,j , repeatability s of indication error and control deviation t; According to the indication error Δ i,j , the repeatability s of the indication error and the control deviation t, to determine whether the pressure measurement system (100) meets the technical indicators.

8. The online calibration method for a pressure measurement system in a pressure test bench according to claim 1, characterized in that: When the pressure transmission medium is liquid, if the reference plane of the pressure port of the standard device (1) and the reference plane of the pressure port of the pressure transmitter (102) are not on the same horizontal plane, a steel ruler (3) is used to determine the height difference h and make corrections.

9. The online calibration method for a pressure measurement system in a pressure test bench according to claim 1, characterized in that: Also includes: A thermometer (4) and a hygrometer (5) are used to record the ambient temperature and humidity, and the ambient temperature and humidity meet the use requirements of the pressure measurement system (100).

10. The online calibration method for a pressure measurement system in a pressure test bench according to claim 1, characterized in that: Also includes: Before performing online calibration, the overall status of the pressure test bench (10) and the pressure measurement system (100) is checked.

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