A test method for the temperature effect test of pressure gauges

Abstract

This invention relates to a testing method for the temperature effect test of pressure gauges. The method includes placing the pressure gauge under test in a heat preservation chamber of a high and low temperature test chamber; acquiring the actual temperature and pressure within the heat preservation chamber; controlling the temperature rise or fall within the chamber; controlling a pressure generator to increase or decrease the pressure within the chamber; when the actual temperature and pressure within the chamber reach target temperature and target pressure respectively, entering a heat preservation and pressure holding stage; performing an indication detection stage, controlling the pressure generator to bring the actual pressure within the chamber to different calibration points, and acquiring photographic files of the pressure gauge under test through a vision device; based on the photographic files, acquiring indication data, and associating the indication data corresponding to each calibration point with the filename of the photographic file. This invention achieves full automation of the pressure gauge temperature effect test process, significantly improving testing efficiency.

Description

Technical Field

[0001] This invention relates to the field of pressure instrument type evaluation technology, and in particular to a test method for the temperature effect test of pressure instruments. Background Technology

[0002] Type evaluation of pressure instruments (hereinafter referred to as "type evaluation") is a type approval test conducted on new products to verify whether the prototype pressure instruments meet the requirements of the technical specifications. During the type evaluation process, performance and stability tests are performed on multiple pressure instrument samples of one or more models. Only products that pass the type test and meet the requirements can be officially put into production and launched on the market. Type evaluation must be conducted by a qualified metrology verification institution, which must issue the corresponding certification.

[0003] Type evaluation focuses on samples (i.e., pressure gauges under test), with temperature influence testing being a crucial and indispensable part of the process. Temperature influence testing consists of two parts: low-temperature performance testing and high-temperature performance testing. The low-temperature performance test requires holding the sample at -40°C for a specified time (usually 3 hours) under ambient and medium temperatures. Following this, the accuracy of the sample's indication is tested according to the prescribed procedure (i.e., indication detection). Specific steps include: increasing the sample pressure to the pressure at each calibration point, tapping lightly, reading the value, determining the tapping displacement, holding the pressure for 3 minutes, then decreasing the pressure to the pressure at each calibration point, tapping lightly again, reading the value, determining the tapping displacement, and calculating the hysteresis error. The calibration point pressure is typically the pressure corresponding to each major graduation on the pressure gauge under test. Similarly, the high-temperature performance test is conducted at 70°C under the same testing procedure.

[0004] According to the requirements of the "Regulations" and "Type Evaluation Outline", when the temperature reaches -40°C or 70°C, the sample pressure should be pre-increased to 75% of its range, and then maintained at the specified temperature for a specified time (generally 3 hours). After the temperature maintenance is completed, the indicated value should be measured, and the instrument under test and the medium should always maintain the corresponding temperature (-40°C or 70°C).

[0005] Currently, most testing devices place the pressure gauges under test in a high and low temperature test chamber, first cooling them to -40°C and holding them there for 3 hours, then removing the samples and testing their readings at room temperature. Subsequently, the samples are placed back in the chamber, heated to 70°C and held there before completing the high-temperature reading test at room temperature. Some devices in this method connect an external pressure-pressurizing device to the high and low temperature chamber. However, because pressurization, maintaining pressure during the 3-hour process, and reading the readings all require manual operation and readings, not only is it necessary to constantly adjust the pressurizing device to control the pressure within the error range, but also the inspector needs to read the readings of multiple (usually 3) gauges through the observation window during the reading test. This not only results in high labor intensity, low efficiency, unreliable data accuracy, and lack of data traceability, but also violates the regulations by conducting reading tests at room temperature. Therefore, improvements are urgently needed. Summary of the Invention

[0006] Therefore, this invention provides a test method for the temperature effect test of pressure gauges, which realizes the full automation of the pressure gauge temperature effect test process, and can complete the photography and reading of each calibration point without manual intervention, thus greatly improving the testing efficiency.

[0007] To address the aforementioned technical problems, this invention provides a test method for the temperature effect test of pressure instruments, the test method comprising:

[0008] The pressure gauge under test is placed in the insulation chamber of the high and low temperature test chamber. The pressure gauge under test is connected to the digital pressure gauge and the pressure generator through the medium pipeline. Each pressure gauge under test is assigned a vision device and a tapping device. The vision device is used to take pictures of the pressure gauge under test.

[0009] The actual temperature and pressure inside the insulation chamber are obtained. Based on the difference between the actual temperature and the preset target temperature, the temperature inside the insulation chamber is controlled to rise or fall. Based on the difference between the actual pressure and the preset target pressure, the pressure generator is controlled to increase or decrease the pressure inside the insulation chamber.

[0010] When the actual temperature and actual pressure inside the insulation chamber reach the target temperature and the target pressure respectively, the insulation and pressure holding stage begins.

[0011] After the heat preservation and pressure holding stage, the indication detection stage is carried out. The pressure generator is controlled to make the actual pressure in the heat preservation chamber reach different calibration points. The visual device is used to acquire photo files of the pressure gauge under test. The photo files include the indication information of the dial pointer. The photo files include a first sample photo corresponding to each calibration point, and a second sample photo acquired after the pressure gauge under test is tapped by the tapping device at each calibration point.

[0012] Based on the photo file, the indication data is obtained, and the indication data corresponding to each of the calibration points is associated with the file name of the photo file.

[0013] In one embodiment of the present invention, when the actual temperature and actual pressure inside the insulation chamber reach the target temperature and the target pressure, respectively, the insulation and pressure holding stage is entered, including:

[0014] When the actual temperature and pressure inside the insulation chamber reach the corresponding target temperature and pressure, the temperature and / or pressure inside the insulation chamber are controlled and adjusted to maintain stability, and the insulation timer is started at the same time.

[0015] During the heat preservation and pressure holding stage, an alarm is triggered when the temperature and / or pressure inside the heat preservation chamber exceeds the error range.

[0016] In one embodiment of the present invention, after the heat preservation and pressure holding stage, an indication detection stage is performed, including:

[0017] When the accumulated time of heat preservation reaches the preset time, the pressure generator is controlled to depressurize, so that the medium pressure displayed on the digital pressure gauge returns to zero, and the indication detection stage is carried out.

[0018] In one embodiment of the present invention, the preset time is 3 hours.

[0019] In one embodiment of the present invention, the target temperature is -40°C or 70°C.

[0020] In one embodiment of the present invention, when the actual temperature inside the insulation chamber reaches -40°C±2°C or 70°C±2°C, the pressure generator is controlled to pre-pressurize the pressure of the pressure gauge under test to 75% of its range.

[0021] In one embodiment of the present invention, after controlling the pressure generator to bring the actual pressure inside the insulation chamber to different calibration points, the visual device acquires photographic files of the pressure gauge under test, including:

[0022] At zero pressure, the vision device is controlled to take the first zero-pressure point photograph of the pressure gauge under test.

[0023] The pressure generator is controlled to gradually increase the pressure to the first calibration point, and the vision device is controlled to take a picture of the first sample of the pressure gauge under test.

[0024] The tapping device is controlled to tap the pressure gauge under test, causing the dial pointer to shake slightly. After the tapping is completed, the vision device is controlled to take a picture of the second sample.

[0025] Repeat the above operation, gradually increasing the pressure to each verification point, and obtain the corresponding first sample photo and second sample photo at each verification point during the pressure increase process;

[0026] After pressurization is completed, the pressure is gradually reduced to each verification point. At each verification point during the pressure reduction process, the corresponding first sample photo and second sample photo are obtained until the pressure returns to zero, and the last sample zero-pressure point photo is obtained.

[0027] In one embodiment of the present invention, when the pressure is increased to the highest pressure calibration point, the pressure is held for 3 minutes.

[0028] In one embodiment of the present invention, the high and low temperature test chamber further includes a refrigeration unit and a hot air generator. The refrigeration unit includes evaporator copper tubes arranged in the insulation layer for cooling the insulation chamber. The hot air generator is connected to the insulation chamber through a pipeline and delivers hot air into the insulation chamber to raise the temperature of the insulation chamber.

[0029] In one embodiment of the invention, the vision device includes an industrial camera configured for each of the pressure gauges being inspected.

[0030] The technical solution of the present invention has the following advantages compared with the prior art:

[0031] This invention discloses a test method for the temperature influence test of pressure gauges, which fully automates the traditional manual operation of the pressure gauge temperature influence test process. The method includes temperature control, pressure adjustment, photographing, indication detection, and data storage. Photographing and indication reading at each calibration point can be completed without manual intervention, significantly improving testing efficiency. The indication data at each calibration point is saved as a linked photo file, providing visual evidence for all test data, facilitating traceability and verification. The system can retrieve photos for any data point, ensuring transparency and data traceability in the testing process. Attached Figure Description

[0032] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0033] Figure 1 This is a flowchart of the test method for the temperature effect test of pressure gauges according to the present invention.

[0034] Figure 2 This is a front view of the automatic detection system for the temperature effect test of pressure gauges according to the present invention.

[0035] Figure 3 This is a top view of the automatic detection system for the temperature effect test of pressure gauges according to the present invention.

[0036] Figure 4 This is a side view of the automatic detection system for the temperature effect test of pressure gauges according to the present invention.

[0037] Explanation of reference numerals in the instruction manual:

[0038] 1. Camera; 2. Camera mounting plate; 3. Insulation chamber; 4. Mounting plate; 5. Evaporator copper pipe; 6. Insulation layer; 7. High and low temperature test chamber; 8. Standard digital pressure gauge; 9. Host computer; 10. Electrical auxiliary cabinet; 11. Pressure generator; 12. Pressure generator cabinet; 13. Media pipeline; 14. Lighting lamp; 15. Insulation chamber door; 16. Observation window; 17. Insulated glass; 18. Camera cabinet; 20. Threaded connector; 21. Sample mounting base; 22. Hot air generator; 23. Refrigeration unit; 24. Controller; 25. Camera data cable; 26. Pressure gauge under test; 27. Controller cable. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0040] In this invention, when directions (up, down, left, right, front, and back) are described, it is only for the convenience of describing the technical solution of this invention, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0041] In this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number. In the description of this invention, the terms "first" and "second" are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0042] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; a fixed connection, a detachable connection, or an integrally formed connection; a mechanical connection, an electrical connection, or a connection capable of mutual communication; or the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention based on the specific content of the technical solution.

[0043] Reference Figure 1 As shown, a test method for the temperature effect test of a pressure instrument is provided, the test method comprising:

[0044] S1. Place the pressure gauge 26 to be tested in the insulation chamber 3 of the high and low temperature test chamber. Connect the pressure gauge 26 to the digital pressure gauge and pressure generator 11 through the medium pipeline 13. Assign a vision device and a tapping device to each pressure gauge 26 to be tested. The vision device is used to take pictures of the pressure gauge 26.

[0045] In this embodiment, the high and low temperature test chamber further includes a refrigeration unit 23 and a hot air generator 22. The refrigeration unit 23 includes an evaporator copper tube 5 arranged in the insulation layer 6 for cooling the insulation chamber 3. The hot air generator 22 is connected to the insulation chamber 3 through a pipeline and supplies hot air into the insulation chamber 3 to raise its temperature. The vision device includes an (industrial) camera 1 configured for each of the pressure gauges 26 under test. An illumination lamp 14 is also provided on the top of the insulation chamber 3 to illuminate the pressure gauges 26 under test. The illumination lamp 14 provides the necessary brightness for taking pictures.

[0046] When setting up the specific configuration, refer to... Figures 2 to 4 As shown, a temperature sensor is arranged inside the insulation chamber 3; a sample mounting base 21 is also provided at the bottom of the insulation chamber 3, and a mounting base plate 4 is installed on the sample mounting base 21. A threaded connector 20 for installing the pressure gauge 26 under test is arranged on the mounting base plate 4, and the threaded connector 20 is connected to the medium pipeline 13.

[0047] In addition, the insulation chamber 3 includes an insulation chamber door 15, on which an observation window 16 is provided. The observation window 16 includes at least one layer of transparent heat-insulating glass 17 with heating function. The use of transparent heat-insulating glass 17 with heating function can not only prevent frost or fogging from affecting observation, but also play a role in heat insulation.

[0048] A camera cabinet 18 is mounted on the outside of the observation window 16. Each camera 1 is mounted on the camera mounting base plate 2 of the camera cabinet 18, and each pressure gauge 26 under test is matched with one camera 1. A lighting lamp 14 is also provided on the top of the insulation chamber 3 to illuminate the pressure gauges 26 under test. The lighting lamp 14 provides the necessary brightness environment for taking pictures. The camera cabinet 18 provides a stable mounting platform for the cameras 1 while preventing external interference from affecting the shooting effect. The lighting lamp 14 optimizes the shooting environment, ensuring the clarity of images captured under different conditions and supporting data acquisition by the vision device.

[0049] The observation window 16 is designed to facilitate real-time viewing of the equipment's operating status, improving operational convenience. The camera 1, located in front of the observation window 16, can take pictures of the sample through the glass.

[0050] The high and low temperature test chamber, through the refrigeration unit 23 and the hot air generator 22, can precisely control the temperature between -40°C and 70°C to meet the testing requirements. The pressure generator 11, used in conjunction with a digital pressure gauge, monitors and adjusts the medium pressure in real time, ensuring stable pressure and controllable error range during testing. The tapping device can be an existing electromagnet-driven tapping device.

[0051] In this embodiment, the high and low temperature test chamber, digital pressure gauge, and pressure generator 11 are connected to the control system via data cables, allowing the temperature and medium pressure to be controlled by the control system. The control system includes a host computer 9 and a controller 24. The pressure generator 11 is connected to the controller 24 via a cable, and the camera 1 is connected to the host computer 9 via a data cable. The host computer 9 controls the camera 1 to take pictures, and the pictures are saved in a designated location on the host computer 9. The host computer 9 sends control commands to the controller 24, and the controller 24, upon receiving the commands, controls the pressure generator 11 to increase, maintain, or decrease the pressure. The controller 24 is a PLC or a microcontroller.

[0052] S2. Obtain the actual temperature and actual pressure inside the insulation chamber 3, and control the temperature inside the insulation chamber 3 to rise or fall according to the difference between the actual temperature and the preset target temperature; control the pressure generator 11 to increase or decrease the pressure inside the insulation chamber 3 according to the difference between the actual pressure and the preset target pressure.

[0053] Specifically, the target temperature is -40°C or 70°C; when the actual temperature inside the insulation chamber 3 reaches -40°C±2°C or 70°C±2°C, the pressure generator 11 is controlled to pre-pressurize the pressure of the pressure gauge 26 under test to 75% of its range.

[0054] S3. When the actual temperature and actual pressure inside the insulation chamber 3 reach the target temperature and the target pressure respectively, the insulation and pressure holding stage begins.

[0055] Specifically, when the actual temperature and actual pressure inside the insulation chamber 3 reach the corresponding target temperature and target pressure, the temperature and / or pressure inside the insulation chamber 3 are controlled and adjusted to maintain stability, and the insulation timer is started at the same time.

[0056] During the heat preservation and pressure holding stage, an alarm is triggered when the temperature and / or pressure inside the heat preservation chamber 3 exceeds the error range.

[0057] S4. After the heat preservation and pressure holding stage, when the accumulated heat preservation time reaches the preset time, the pressure generator 11 is controlled to depressurize, so that the medium pressure displayed on the digital pressure gauge returns to zero, and the indication detection stage is performed. The preset time is 3 hours.

[0058] After controlling the pressure generator 11 to make the actual pressure in the insulation chamber 3 reach different calibration points, the visual device acquires a photo file of the pressure gauge 26 under test. The photo file includes the indication information of the dial pointer. The photo file includes a first sample photo corresponding to each calibration point, and a second sample photo acquired after the pressure gauge 26 under test is tapped by the tapping device at each calibration point.

[0059] Specifically, at zero pressure, the vision device is controlled to take the first zero-pressure point photograph of the pressure gauge under test 26.

[0060] The pressure generator 11 is controlled to gradually increase the pressure to the first calibration point, and the vision device is controlled to take a picture of the first sample of the pressure gauge 26 under test.

[0061] The tapping device is controlled to tap the pressure gauge 26 under test, causing the dial pointer to shake slightly. After the tapping is completed, the vision device is controlled to take a picture of the second sample.

[0062] Repeat the above operation, gradually increasing the pressure to each verification point, and obtain the corresponding first sample photo and second sample photo at each verification point during the pressure increase process;

[0063] After pressurization, the pressure is gradually reduced to each verification point. At each verification point during the pressure reduction process, the corresponding first sample photo and second sample photo are obtained until the pressure returns to zero, at which point the final sample zero-pressure photo is obtained. In addition, when the pressure is increased to the highest verification point, it is necessary to maintain the pressure for 3 minutes.

[0064] The tapping device simulates a manual tap on the gauge case, causing the pointer to swing and eliminating the frictional hysteresis effect, thus ensuring the accuracy of the readings. Photos are taken before and after the tapping at each calibration point, and the pointer movement is compared and analyzed to more accurately calculate the pressure gauge's measurement error.

[0065] S5. Based on the photo files, obtain the indication data, and associate the indication data corresponding to each of the verification points with the filenames of the photo files. Clicking on the data will bring up the corresponding photo file for verification of the indication data. After the test is completed, both the indication data and the photo files are saved. When querying the indication data obtained from the test of each sample, the corresponding photo can be displayed simultaneously, realizing the traceability of the indication data.

[0066] It is understandable that by combining the readings of the second sample photograph obtained after tapping the pressure gauge 26 by the tapping device with the readings of the first sample photograph, the tapping displacement of each calibration point can be obtained.

[0067] The readings at each testing point are saved as associated photo files, providing visual evidence for all test data and facilitating traceability and verification. The system can retrieve photos of any data point, ensuring transparency in the testing process and traceability of the data.

[0068] For example, after the pressure value stabilizes at each calibration point, the system controls the camera to take a picture of the pressure gauge under test. Each picture contains the pressure gauge dial and its pointer position. The naming rules for the picture files include information such as the test time, pressure calibration point, and tapping state (before or after). All picture files are saved in separate directories according to the sample number. The file name of each picture is mapped to the corresponding test point reading data and is stored in the system database. In the query interface, test data can be quickly located by sample number, test time, or pressure point. Clicking on the reading data will simultaneously bring up the corresponding picture, displaying the pointer position and scale lines on the picture.

[0069] In addition, the system automatically marks detection points that exceed the error range and prompts the user to review and check them. During the photo review process, the user can correct the displayed values. After correction, the system automatically records the modification operation and time, and retains the original data and photos.

[0070] Specifically, the host computer 9 parses each photo file through a vision processing procedure to obtain the value of the sample pointer within it. This value data is then displayed at a specific location on the test page via the host computer 9 program. For example, the specific process is as follows:

[0071] The vision device takes a picture of the pressure gauge 26 under test in a zero-pressure state and saves the picture.

[0072] The software processes the photo: locates the dial position and crops the portion outside the dial; performs grayscale processing (dividing the photo's grayscale values ​​into 0-255 levels based on a logarithmic relationship); filters to remove noise; and binarizes the image to achieve a clear black and white effect. It then locates the pointer in the processed photo and marks its first center line.

[0073] First calibration point test: Apply pressure to the pressure gauge 26 under test. When the pressure reaches the corresponding pressure value of the first calibration point, stop applying pressure and maintain the pressure for a period of time to take a picture. Take a picture of the gauge under test at this time and save it. Process the picture and mark the second center line of the pointer.

[0074] Establish a coordinate system with the intersection of the first center line and the second center line as the origin; identify the scale area in the photo and mark the scale lines; calculate the pressure value pointed to by the pointer based on the angle between the scale lines and the center line.

[0075] Continuously apply pressure to the gauge under test, gradually reaching each preset pressure value, and repeat the following steps:

[0076] Take a photograph of the gauge under test at each pressure point; process the photograph, mark the pointer center line, and calculate the pointer pressure value using a coordinate system; compare the calculated pressure value (P1) with the applied system pressure value (P2) and the pressure value read manually from the photograph (P3); if the error at the pressure point is within the permissible range, continue testing the next pressure point; if the error exceeds the permissible range, determine that the gauge under test is not accurate enough.

[0077] Test result recording and display: After the test is completed at the last preset pressure point, if the error of all points is within the permissible range, the accuracy of the tested instrument is determined to be up to standard; otherwise, the accuracy is determined to be down to standard.

[0078] During the testing process, all readings (P1) are displayed on the computer screen in real time; clicking on any reading will display the corresponding real-time photo. If there is a deviation between P1 and P3, manual corrections can be made, and the correction records are saved. Multiple test forms can be tested simultaneously, improving testing efficiency. Each test form is photographed by an independent camera 1, and the data is recorded and processed separately.

[0079] This process ensures the accuracy, efficiency, and reliability of the testing, while also providing data traceability and verification capabilities.

[0080] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0081] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0082] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0083] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0084] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A test method for the temperature effect test of a pressure instrument, characterized in that, The testing method includes: The pressure gauge under test is placed in the insulation chamber of the high and low temperature test chamber. The pressure gauge under test is connected to the digital pressure gauge and the pressure generator through the medium pipeline. Each pressure gauge under test is assigned a vision device and a tapping device. The vision device is used to take pictures of the pressure gauge under test. The actual temperature and pressure inside the insulation chamber are obtained. Based on the difference between the actual temperature and the preset target temperature, the temperature inside the insulation chamber is controlled to rise or fall. Based on the difference between the actual pressure and the preset target pressure, the pressure generator is controlled to increase or decrease the pressure inside the insulation chamber. When the actual temperature and actual pressure inside the insulation chamber reach the target temperature and the target pressure respectively, the insulation and pressure holding stage begins. After the heat preservation and pressure holding stage, the indication detection stage is carried out. The pressure generator is controlled to make the actual pressure in the heat preservation chamber reach different calibration points. The visual device is used to acquire photo files of the pressure gauge under test. The photo files include the indication information of the dial pointer. The photo files include a first sample photo corresponding to each calibration point, and a second sample photo acquired after the pressure gauge under test is tapped by the tapping device at each calibration point. Based on the photo file, the indication data is obtained, and the indication data corresponding to each of the calibration points is associated with the file name of the photo file.

2. The test method for the temperature effect test of a pressure instrument according to claim 1, characterized in that, When the actual temperature and actual pressure inside the insulation chamber reach the target temperature and the target pressure, respectively, the insulation and pressure holding stage begins, including: When the actual temperature and pressure inside the insulation chamber reach the corresponding target temperature and pressure, the temperature and / or pressure inside the insulation chamber are controlled and adjusted to maintain stability, and the insulation timer is started at the same time. During the heat preservation and pressure holding stage, an alarm is triggered when the temperature and / or pressure inside the heat preservation chamber exceeds the error range.

3. The test method for the temperature effect test of a pressure instrument according to claim 2, characterized in that, Following the heat preservation and pressure holding stage, an indication detection stage is performed, including: When the accumulated time of heat preservation reaches the preset time, the pressure generator is controlled to depressurize, so that the medium pressure displayed on the digital pressure gauge returns to zero, and the indication detection stage is carried out.

4. The test method for the temperature effect test of a pressure instrument according to claim 3, characterized in that, The preset time is 3 hours.

5. The test method for the temperature effect test of a pressure instrument according to claim 1, characterized in that, The target temperature is -40°C or 70°C.

6. The test method for the temperature effect test of a pressure instrument according to claim 1, characterized in that, When the actual temperature inside the insulation chamber reaches -40°C±2°C or 70°C±2°C, the control pressure generator pre-pressurizes the pressure of the pressure gauge under test to 75% of its range.

7. The test method for the temperature effect test of a pressure instrument according to claim 1, characterized in that, After controlling the pressure generator to bring the actual pressure inside the insulation chamber to different calibration points, the visual device acquires photographic files of the pressure gauge under test, including: At zero pressure, the vision device is controlled to take the first zero-pressure point photograph of the pressure gauge under test. The pressure generator is controlled to gradually increase the pressure to the first calibration point, and the vision device is controlled to take a picture of the first sample of the pressure gauge under test. The tapping device is controlled to tap the pressure gauge under test, causing the dial pointer to shake slightly. After the tapping is completed, the vision device is controlled to take a picture of the second sample. Repeat the above operation, gradually increasing the pressure to each verification point, and obtain the corresponding first sample photo and second sample photo at each verification point during the pressure increase process; After pressurization is completed, the pressure is gradually reduced to each verification point. At each verification point during the pressure reduction process, the corresponding first sample photo and second sample photo are obtained until the pressure returns to zero, and the last sample zero-pressure point photo is obtained.

8. The test method for the temperature effect test of a pressure instrument according to claim 1, characterized in that, When the pressure is increased to the highest pressure calibration point, hold the pressure for 3 minutes.

9. The test method for the temperature effect test of a pressure instrument according to claim 1, characterized in that, The high and low temperature test chamber also includes a refrigeration unit and a hot air generator. The outer wall of the insulation chamber is provided with an insulation layer. The refrigeration unit includes evaporator copper tubes arranged in the insulation layer to cool down the insulation chamber. The hot air generator is connected to the insulation chamber through a pipeline and delivers hot air into the insulation chamber to raise the temperature of the insulation chamber.

10. The test method for the temperature effect test of a pressure instrument according to claim 1, characterized in that, The vision device includes an industrial camera configured for each of the pressure gauges being inspected.

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