Pressure vessel pressure tester and use method thereof

Abstract

The invention relates to the field of pressure testing instruments, and provides a pressure container pressure testing instrument and a using method thereof in order to solve the problem that in the prior art, the maintenance pressure testing time of a pressure container is long, the pressure container pressure testing instrument comprises a medium conveying mechanism, a pressure measuring component, a temperature measuring component and a processor, and the medium conveying mechanism is used for conveying a medium into the pressure container; the pressure measuring part is used for measuring the internal pressure of the pressure container; the temperature measuring part is used for measuring the wall temperature of the pressure vessel; the medium conveying mechanism, the pressure measuring part and the temperature measuring part are all connected with the processor. According to the pressure container pressure tester provided by the invention, pressure data and temperature data of the container are detected and transmitted through the pressure measuring part and the temperature measuring part, and the processor processes and stores the data after receiving the data; according to the maintenance pressure test of the pressure vessel, the initial curve obtained through the initial pressure test is compared with the real-time curve, the state of the pressure vessel is judged in real time, quick judgment can be conducted when the pressure vessel leaks or deforms, and the pressure test time and the observation work of the vessel state are reduced.

Description

Technical Field

[0001] The present invention relates to the field of pressure testers, and in particular to a pressure tester for a pressure vessel and a method for using the same. Background Art

[0002] A pressure vessel refers to a closed device that contains gas or liquid and bears a certain pressure. Its scope is defined as gases and liquefied gases with a maximum working pressure greater than or equal to 0.1 MPa (gauge pressure), and liquids with a maximum working temperature higher than or equal to the standard boiling point, fixed containers and mobile containers with a volume greater than or equal to 30L and an inner diameter (non-circular cross-section refers to the maximum geometric dimension of the inner boundary of the cross-section) greater than or equal to 150mm; gas cylinders and oxygen chambers containing gases and liquefied gases with a nominal working pressure greater than or equal to 0.2MPa (gauge pressure) and a product of pressure and volume greater than or equal to 1.0MPa•L, and liquids with a standard boiling point equal to or lower than 60℃.

[0003] After pressure vessels are manufactured, they undergo a final pressure test. The purpose of the pressure test is to comprehensively verify the strength (pressure resistance test) and tightness (air tightness test) of the pressure-bearing components of the pressure vessel. It is a comprehensive inspection of the vessel's material selection, design calculations, structure, and manufacturing quality. During the test, the pressure-bearing components are observed for obvious deformation or cracking to verify whether the pressure vessel has the necessary pressure-bearing capacity for safe operation under the design pressure. At the same time, the tightness of the pressure vessel is verified by observing the welds, flanges, and other joints for leakage.

[0004] During the use of pressure vessels, pressure testing is usually required to ensure that they can operate safely within the design parameters. The pressurization time ranges from 30 minutes to several hours, and the pressure testing time during maintenance is longer. Summary of the Invention

[0005] The object of the present invention is to provide a pressure tester for a pressure vessel and a method for using the same, so as to solve the problem in the prior art that the maintenance and pressure testing time of the pressure vessel is long.

[0006] The embodiments of the present invention are achieved through the following technical solutions:

[0007] A pressure tester for a pressure vessel comprises: a medium conveying mechanism, a pressure measuring component, a temperature measuring component and a processor, wherein the medium conveying mechanism is used to convey a medium into the pressure vessel; the pressure measuring component is used to measure the internal pressure of the pressure vessel; the temperature measuring component is used to measure the wall temperature of the pressure vessel; the medium conveying mechanism, the pressure measuring component and the temperature measuring component are all connected to the processor.

[0008] A method for using the pressure vessel pressure tester includes:

[0009] S100, during the initial pressure test, obtaining the internal pressure and wall temperature of the container in real time, constructing an initial curve based on the internal pressure, wall temperature, and time; and storing the initial curve and its corresponding pressure test process parameters in a processor;

[0010] S200, when performing maintenance inspection and pressure testing on the pressure vessel, the pressure test is performed using the pressure test process parameters of the initial pressure test; a real-time curve is constructed in real time based on the internal pressure, the vessel wall temperature, and time, and the real-time curve is compared with the initial curve in real time to obtain a deviation value;

[0011] S300 , obtaining a difference between the deviation value and a set threshold value; when the difference is less than or equal to 0, storing the real-time curve as a historical curve in the processor.

[0012] Preferably, the S200 includes: continuously comparing the real-time curve generated in real time with the initial curve to continuously generate an array of deviation values;

[0013] The step S300 includes: obtaining a difference between each deviation value and a set threshold value; and determining whether to continue the pressure test according to the difference.

[0014] Preferably, a difference curve is constructed by the difference to obtain the difference change rate; when the fluctuation value of the difference change rate within the set time range is less than or equal to the fluctuation threshold, the pressure test continues; when the fluctuation value of the difference change rate within the set time range is greater than the fluctuation threshold, the pressure test is stopped.

[0015] Preferably, the fluctuation value of the difference change rate within the set time range , Indicates the The rate of change of the difference at each moment, Represents the arithmetic mean of all difference change rate data, is the number of difference change rate data.

[0016] Preferably, the time range t=aT used for calculating the fluctuation value; wherein T is the total time of the initial pressure test, a is a constant, 0<a<1.

[0017] Preferably, the first-order derivative function curve of the difference curve is a difference change rate curve.

[0018] Preferably, the method further comprises: after the historical curve is stored in the processor, a deviation value is obtained by comparing the real-time curve constructed by the next pressure test with the most recently acquired historical curve.

[0019] Preferably, after the pressure vessel is repaired or parts are replaced, the initial pressure test is performed again to construct an initial curve and replace the original initial curve in the processor.

[0020] Preferably, during the initial pressure test, when the internal pressure of the container P1=bP2, the medium delivery speed is reduced, where P2 is the design pressure of the pressure container and b is a constant.

[0021] The present invention has at least the following beneficial effects:

[0022] The pressure vessel pressure tester provided by the present invention can detect and transmit the pressure data and temperature data of the container in real time through the pressure measuring component and the temperature measuring component. After receiving the data, the processor processes and stores the data. The maintenance pressure test of the pressure vessel can compare the initial curve obtained by the initial pressure test with the real-time curve to judge the status of the pressure vessel in real time. When the pressure vessel leaks or deforms, it can be quickly judged, reducing the pressure test time and the observation work of the container status. Since the various performances of the pressure vessel will change during use, the curve obtained by the maintenance pressure test will be stored during each maintenance pressure test so that it can be called up during the next maintenance pressure test data analysis, thereby improving the accuracy of the data analysis results. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 This is the structural diagram of the pressure tester for pressure vessels;

[0025] Icons: 1-medium conveying mechanism, 2-pressure measuring component, 3-temperature measuring component, 4-processor, 5-pressure vessel, 6-inlet valve, 7-pressure relief valve. DETAILED DESCRIPTION

[0026] In order to make the purpose, method scheme and advantages of the embodiments of the present invention clearer, the method scheme in the embodiments of the present invention is clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0027] Example 1: Figure 1 As shown, a pressure tester for a pressure vessel includes: a medium conveying mechanism, a pressure measuring component, a temperature measuring component and a processor, wherein the medium conveying mechanism is used to convey the medium into the pressure vessel; the pressure measuring component is used to measure the internal pressure of the pressure vessel; the temperature measuring component is used to measure the wall temperature of the pressure vessel; the medium conveying mechanism, the pressure measuring component and the temperature measuring component are all connected to the processor.

[0028] In specific implementations, the medium delivery mechanism can utilize an air compressor or a pressure test pump. The pressure measurement component can utilize a pressure sensor or a combination of a pressure gauge and a pressure transmitter. The temperature measurement component can utilize a temperature sensor. The processor can utilize a computer. An inlet valve can be installed at the inlet of the pressure vessel, and a pressure relief valve can be installed at the outlet. Both the inlet valve and the pressure relief valve can also be directly electrically connected to the processor, allowing the processor to control the opening and closing of the two valves.

[0029] During the pressure test, the inlet valve is opened, and the medium, typically water, is continuously fed into the pressure vessel via the medium delivery mechanism for a hydrostatic test. During this process, the pressure and temperature measuring components acquire data in real time and transmit it to a processor for processing, analysis, and storage. Finally, based on the results of the data analysis, the processor issues an action command, such as closing the medium delivery mechanism, opening the pressure relief valve, or terminating the pressure test.

[0030] Example 2: This example provides a method for using the pressure vessel pressure tester, comprising:

[0031] S100, during the initial pressure test, obtaining the internal pressure and wall temperature of the container in real time, constructing an initial curve based on the internal pressure, wall temperature, and time; and storing the initial curve and its corresponding pressure test process parameters in a processor;

[0032] S200, when performing maintenance inspection and pressure testing on the pressure vessel, the pressure test is performed using the pressure test process parameters of the initial pressure test; a real-time curve is constructed in real time based on the internal pressure, the vessel wall temperature, and time, and the real-time curve is compared with the initial curve in real time to obtain a deviation value;

[0033] S300 , obtaining a difference between the deviation value and a set threshold value; when the difference is less than or equal to 0, storing the real-time curve as a historical curve in the processor.

[0034] During the specific implementation process, the applicant hopes that the pressure tester can realize the self-test function. During the use of the pressure vessel, it can automatically detect and judge the status of the vessel regularly, without the need to manually start the pressure test and determine the status of the vessel through observation. It is suitable for manufacturers who need to use a large number of pressure vessels in the production process. The pressure test data of all pressure vessels can be processed by a central processor. At the same time, each pressure vessel can be equipped with identification information, such as number information and location information. When it is detected that the pressure bearing performance of a pressure vessel does not meet the standard or a leak occurs, the identification information of the pressure vessel can be displayed by the central processor or the aforementioned identification information can be directly transmitted to the maintenance personnel terminal so that the maintenance personnel can repair the pressure vessel. The maintenance personnel terminal can be a mobile phone, etc., which receives the identification information through the APP.

[0035] The initial curve can be constructed into a three-dimensional curve using internal pressure, wall temperature, and time. At least one of the internal pressure data points in the initial curve reaches the design pressure of the pressure vessel, i.e., the maximum pressure it can withstand. The maintenance and inspection of pressure vessels serves at least two purposes: to detect leaks and to verify the structural stability of the pressure vessel at the design pressure. If a leak is detected before the internal pressure reaches the design pressure, the flow of media can be stopped. After repairs are completed, the structural stability of the vessel at the design pressure can be tested after maintenance.

[0036] In order to detect container leaks in a timely manner without human observation and reduce pressure testing time, this embodiment, during maintenance inspection and pressure testing, constructs a real-time curve from the real-time data acquired and continuously compares it with the partial curve of the initial curve corresponding to the time period, thereby determining the overlap between the two in real time. When the pressure in the real-time curve is significantly lower than the initial curve, it is necessary to consider that the pressure vessel may have a leak. If the deviation is not large, the pressure test can be continued to avoid data deviation caused by the accuracy of the data detection mechanism. When the deviation exceeds a set threshold, it indicates that the pressure vessel is very likely to have a leak and the pressure test can be stopped. The set threshold can be set manually according to actual conditions.

[0037] After the leak is repaired, a second pressure test can be performed to re-check the container for leaks, and this cycle continues until the test result confirms no leaks. During the pressure test where the test result confirms no leaks, the medium can be continuously supplied until the internal pressure of the pressure vessel reaches at least the design pressure. The real-time curve corresponding to this pressure test is then stored in the processor as a historical curve. During the next pressure test, this historical curve is compared with the real-time curve to determine the condition of the pressure vessel.

[0038] Pressure test process parameters can be selected based on actual conditions. Pressure vessels with different structures, specifications, or materials can use the same or different pressure test process parameters. Pressure test process parameters may include: pressure, medium temperature, medium delivery speed, and pressure holding time.

[0039] Example 3: To further improve the accuracy of the data analysis and judgment results, an improvement is made based on Example 2. In this example, S200 includes: continuously comparing the real-time curve generated in real time with the initial curve to continuously generate an array of deviation values;

[0040] The step S300 includes: obtaining a difference between each deviation value and a set threshold value; and determining whether to continue the pressure test according to the difference.

[0041] A difference curve is constructed through the difference to obtain the difference change rate; when the fluctuation value of the difference change rate within the set time range is less than or equal to the fluctuation threshold, the pressure test continues; when the fluctuation value of the difference change rate within the set time range is greater than the fluctuation threshold, the pressure test is stopped.

[0042] In practice, the source of the deviation could be due to issues with the accuracy of the testing equipment or a leak in the container, resulting in a relative decrease in internal pressure. If the issue is with the testing equipment, the data difference will likely remain consistent. However, the rate of leakage from the leak is related to the container's internal pressure. As the medium is continuously conveyed, the internal pressure gradually increases, and the rate of gas escaping from the leak increases. Therefore, the change in container internal pressure is related to the magnitude of the internal pressure, the number of leaks, and their size. The deviation will not be due to the accuracy of the equipment, and will generally remain relatively stable.

[0043] To better distinguish the two aforementioned data deviations and improve the accuracy of the test and analysis results, this embodiment no longer directly uses the magnitude of the deviation as the basis for judgment. Instead, it uses the change in the difference as the basis for judgment. If the fluctuation in the rate of change of the difference is small, the current data deviation is likely caused by the accuracy deviation of the data detection equipment itself, and the pressure test operation continues. If the fluctuation in the rate of change of the difference is large, the container is likely to have a leak. In this case, the pressure test operation is stopped and the pressure vessel is repaired.

[0044] Example 4: In order to better obtain the fluctuation value, an improvement is made on the basis of Example 3. In this example, the fluctuation value of the difference change rate within the set time range is , Indicates the The rate of change of the difference at each moment, Represents the arithmetic mean of all difference change rate data, is the number of difference change rate data.

[0045] During implementation, to reduce the complexity of data processing, the calculation of the fluctuation value in this embodiment does not include all previously acquired data in the data processing scope. This reduces the amount of data to be processed while also ensuring the accuracy of the data results. If, based on previous data, it is determined that no leaks exist at the current pressure, there is no need to include previously acquired data in the subsequent calculation of the fluctuation value. This not only increases the data processing load, but also may result in a relatively small overall fluctuation value in the early stages of significant fluctuations in the later data due to the excessive amount of previous data, making it difficult to promptly determine if a container leak exists.

[0046] The time range can be set from a-5min to a, where a is the current time. This means that the data from the previous 5 minutes to the current time will be used for fluctuation calculation. Of course, the time range of the selected data can be set according to the actual situation.

[0047] Example 5: In order to more simply set the time range for fluctuation value calculation, an improvement is made on the basis of Example 4. In this example, the time range t=aT used for the fluctuation value calculation is used; wherein T is the total time of the initial pressure test, a is a constant, 0<a<1.

[0048] In a specific implementation, the length of time t can refer to the total time used for medium delivery during the initial pressure test, thereby providing a certain reference basis for the time range used in the fluctuation value calculation when the pressure tester of this embodiment is applied to different pressure vessels.

[0049] For example, a=0.1.

[0050] Example 6: In order to obtain the difference change rate more intuitively and simply, an improvement is made on the basis of Example 5. In this example, the first-order derivative function curve of the difference curve is the difference change rate curve.

[0051] During specific implementations, the tangent of the difference curve can be used to characterize the trend of the difference. Therefore, in this embodiment, the first-order derivative of the difference curve is used as the difference change rate curve. The ordinates corresponding to points on the difference change rate curve represent the speed of change in the difference. When the difference changes rapidly and shows an upward trend, it can be determined that a leak exists in the pressure vessel.

[0052] Example 7: In order to improve the accuracy of each pressure test, an improvement is made based on Example 4. In this embodiment, it also includes: after the historical curve is stored in the processor, the real-time curve constructed by the next pressure test is compared with the most recently obtained historical curve to obtain a deviation value.

[0053] During the specific implementation process, during use, with the passage of time, the materials used in the pressure vessel will undergo a natural aging process, such as metal fatigue, creep and other phenomena, which will lead to a reduction in the strength of the material, thereby affecting the pressure-bearing capacity of the pressure vessel. If there is a corrosive medium inside the pressure vessel or in the external environment, the container wall may become thinner due to corrosion, which will directly weaken the structural strength and pressure resistance of the container. Of course, being in a high temperature or low temperature environment for a long time may also affect the physical properties of the pressure vessel material, such as causing problems such as embrittlement or softening of the material, thereby affecting its pressure-bearing capacity. It can be seen that the performance of the pressure vessel itself will gradually decrease over time, and the initial curve obtained during the initial pressure test may not necessarily be applicable to pressure vessels that have been used for a long time. Therefore, this embodiment proposes that after the pressure test is completed, the real-time curve obtained is used as the comparison basis for the next pressure test, increasing the applicability of the two comparison results in characterizing the state of the pressure vessel.

[0054] Example 8: In order to better compare data, an improvement is made based on Example 7. In this example, after the pressure vessel is repaired or parts are replaced, the initial pressure test is performed again, the initial curve is constructed and the original initial curve in the processor is replaced.

[0055] During the specific implementation process, the performance of the pressure vessel may change significantly after repair or replacement of parts. The initial curve obtained previously may not be applicable to the current pressure vessel. Therefore, after the pressure vessel has been repaired or replaced, it can be treated as a brand new pressure vessel for initial pressure testing.

[0056] Example 9: In order to improve the safety of the pressure test process, improvements are made based on Example 8. In this example, during the initial pressure test process, when the internal pressure of the container P1=bP2, the medium delivery speed is reduced, P2 is the design pressure of the pressure vessel, and b is a constant.

[0057] During the specific implementation process, at the initial stage of the pressure test, the medium conveying mechanism has a faster conveying speed in order to quickly increase the internal pressure of the container. However, in the later stage of the pressure test, if the pressure increases too quickly, the container may be subjected to a greater impact after the pressure exceeds the critical pressure that ensures the stability of the container structure, causing it to deform rapidly and even seriously affecting the surrounding safety.

[0058] For example, the pressure test process can be carried out by means of a water pressure test. A water pressure test is a pressure test of the pressure-bearing components of boilers, pressure vessels, and pressure pipes using water as the medium at a specified test pressure. The importance of the pressure vessel water pressure test is mainly reflected in the following two aspects:

[0059] ① Checking the compressive strength of pressure-bearing parts can effectively avoid accidents caused by damage to pressure-bearing parts and defects that are difficult to be discovered during operation.

[0060] ② Check whether the pressure-bearing parts and their welds, expansion joints, sealing surfaces (manholes, inspection holes, hand holes), flanges (or bolts) and other joints are tight and whether there is any leakage.

[0061] Hydrostatic testing is a testing method or inspection technique that can improve vessel performance, mechanically eliminate stress, and effectively de-energize cuts or cracks. Hydrostatic testing exceeding design pressures inherently carries significant risks and potential hazards. Only by scientifically controlling the hydrostatic testing process for pressure vessels and understanding all preparatory steps, test specifications, methods, and essential precautions can the quality of pressure vessels be guaranteed and major safety issues avoided during subsequent use.

[0062] As a result, the collection, recording and processing of important data during the pressure test is particularly important.

[0063] The main functions of the pressure vessel pressure tester designed by the applicant are as follows:

[0064] 1. Real-time collection of internal pressure and temperature data of the container;

[0065] 2. Use a microcomputer to convert and calculate the data required for engineering quantities based on the collected data values;

[0066] 3. Automatically store the calculated pressure and temperature engineering values;

[0067] 4. Draw the curve of the data in real time and store the generated curve for later reference and printing;

[0068] 5. Automatically select the pressure test process according to different containers;

[0069] 6. Intelligently control the pressure / time process section according to the requirements of quality inspection.

[0070] 7. According to the approach of the pressure value to the target value, flexible control output is performed so that the pressure test target value can be accurately obtained;

[0071] 8. Make comprehensive intelligent judgment on the rationality of pressure value according to the change of medium temperature;

[0072] Real-time data collection is achieved through a pressure sensor installed on the container, connected to the instrument itself, collecting initial pressure data from the container into the instrument's microcomputer. The pressure sensor undergoes annual third-party testing and verification, ensuring its accuracy and precision. For ease of on-site use and operation, the connection is designed with a quick-plug and waterproof plug-in design to better protect the equipment.

[0073] After the data is collected into the pressure tester, its signal is in the form of a common signal in industrial sites, and it is impossible to obtain the pressure data value. Therefore, a microcomputer and program calculation method must be used to convert the signal into a data volume to facilitate multi-functional processing such as pressure value display, curve drawing, storage and search.

[0074] The microcomputer can also perform calculations and processing of other functions, such as process identification and control, automatic pressure control, and judgment of the rationality of pressure changes.

[0075] Once the pressure signal is converted into a data word signal, the host computer uses the advantage of large-capacity storage to store the data with a timestamp as a marker, forming a powerful database for later processing and reproduction.

[0076] After the data is stored, the host computer will process the data and draw it into a curve. There are two types of curves: real-time curves and historical curves.

[0077] One type of curve is real-time, meaning the data exists and the curve has visible high and low changes, but only the curve within the visible time range of the window can be seen. The high and low values ​​of data outside the other ranges cannot be seen, and as time goes by, the data is constantly updated.

[0078] The other curve is the historical curve, which can be viewed at any time during and after the pressure test. This facilitates later viewing, analysis, and judgment, and serves as a basis for quality inspection.

[0079] For factory operators, mastering the vessel pressure testing process is challenging and inherently risky. This is a key pain point in safety pressure testing. This instrument integrates a specific pressure testing process into a program. Simply input the relevant parameters of the pressure testing equipment through the host computer window. The instrument automatically identifies the required pressure testing process through program judgment and calculation, enabling precise and effective testing.

[0080] In order to make the pressure value control of the test container more accurate, this instrument has developed a control function that can automatically increase and decrease the pressure. Using PID program calculation, flexible control output is performed according to the approximation of the pressure value to the target value. Accurately obtaining the test pressure target value is no longer a problem.

[0081] Under ideal conditions, the pressure of a liquid has no variable relationship with its temperature.

[0082] However, during the pressure test, the metal container is exposed to the atmosphere, and the liquid is sealed within it, creating a complex complex system. The pressure fluctuates with the external temperature, fluctuating both upwards and downwards. However, could an increase indicate that the pressure test equipment is overpressurizing? Or could a decrease indicate a leak in the container? These phenomena can cause confusion and distraction for the pressure testers. Therefore, to determine if this phenomenon is a leak, an internal identification program has been developed. This program uses the on-site pressure and temperature, the delta value of their change, the relationship between metal expansion and temperature, and the relationship between micro-changes in liquid volume to provide a reasonable and accurate judgment of whether a leak is present.

[0083] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations are readily apparent to those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A pressure tester for a pressure vessel, characterized in that: include: A medium conveying mechanism, the medium conveying mechanism is used to convey the medium into the pressure vessel; A pressure measuring component, the pressure measuring component is used to measure the internal pressure of the pressure vessel; A temperature measuring component, wherein the temperature measuring component is used to measure the wall temperature of the pressure vessel; The processor is connected to the medium conveying mechanism, the pressure measuring component and the temperature measuring component.

2. A method for using the pressure vessel pressure tester according to claim 1, characterized in that: include: S100, during the initial pressure test, obtaining the internal pressure and the wall temperature of the container in real time, and constructing an initial curve based on the internal pressure, the wall temperature, and time; storing the initial curve and its corresponding pressure test process parameters in a processor; S200, when performing maintenance inspection and pressure testing on the pressure vessel, the pressure test is performed using the pressure test process parameters of the initial pressure test; a real-time curve is constructed in real time based on the internal pressure, the vessel wall temperature, and time, and the real-time curve is compared with the initial curve in real time to obtain a deviation value; S300 , obtaining a difference between the deviation value and a set threshold value; when the difference is less than or equal to 0, storing the real-time curve as a historical curve in the processor.

3. The method of use according to claim 2, characterized in that: The S200 includes: continuously comparing the real-time curve generated in real time with the initial curve, and continuously generating an array of deviation values; The step S300 includes: obtaining a difference between each deviation value and a set threshold value; and determining whether to continue the pressure test according to the difference.

4. The method of use according to claim 3, characterized in that: A difference curve is constructed through the difference to obtain the difference change rate; when the fluctuation value of the difference change rate within the set time range is less than or equal to the fluctuation threshold, the pressure test continues; when the fluctuation value of the difference change rate within the set time range is greater than the fluctuation threshold, the pressure test is stopped.

5. The method of use according to claim 4, characterized in that: The fluctuation value of the difference change rate within the set time range , Indicates the The rate of change of the difference at each moment, Represents the arithmetic mean of all difference change rate data, is the number of difference change rate data.

6. The method of use according to claim 5, characterized in that: The time range t=aT used for calculating the fluctuation value is as follows; wherein T is the total time of the initial pressure test, a is a constant, and 0<a<1.

7. The method of use according to claim 4, characterized in that: The first-order derivative function curve of the difference curve is the difference change rate curve.

8. The method of use according to any one of claims 2 to 7, characterized in that: Also includes: After the historical curve is stored in the processor, the real-time curve constructed by the next pressure test is compared with the most recently acquired historical curve to obtain a deviation value.

9. The method of use according to claim 8, characterized in that: After the pressure vessel is repaired or parts are replaced, the initial pressure test is carried out again to construct the initial curve and replace the original initial curve in the processor.

10. The method of use according to claim 8, characterized in that: During the initial pressure test, when the internal pressure of the container P1=bP2, the medium delivery speed is reduced. P2 is the design pressure of the pressure vessel and b is a constant.

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