Seal detection system for pressure vessels and detection method thereof

Abstract

This invention discloses a pressure vessel sealing detection system and method, relating to the field of pressure vessel sealing performance testing technology. It aims to solve the problem that existing technologies cannot simultaneously meet the requirements of high precision, high efficiency, anti-interference, low cost, and adaptability to all scenarios. The system includes a gas source unit, a gas path control unit, a dual differential pressure detection unit, a standard reference tank, an ultrasonic positioning unit, a main control unit, a safety protection unit, and a data management unit. These units are connected via gas and electrical paths to form a closed-loop detection system. The gas source unit includes a high-pressure gas source and a tracer gas source. By setting up a dual differential pressure detection unit, a standard reference tank, and a three-channel temperature sensor array, combined with a temperature compensation algorithm based on the ideal gas law, this invention achieves high-precision, anti-interference detection, overcoming the shortcomings of existing technologies such as large temperature interference and low detection accuracy. It can stably detect 1×10⁻⁶ temperature sensors. ‑ 6 Pa・m 3 / s-level micro-leakage significantly improves detection consistency.

Description

Technical Field

[0001] This invention relates to the field of pressure vessel sealing performance testing technology, and more specifically, to a pressure vessel sealing performance testing system and testing method thereof. Background Technology

[0002] Pressure vessels, as core equipment in strategic industries such as energy, chemical industry, nuclear power, and hydrogen energy, undertake critical functions such as media storage, transportation, and reaction. Their sealing performance directly determines the operational safety and system reliability of the equipment. With the advancement of the "dual carbon" goals, the installed capacity of nuclear power continues to expand, and the hydrogen energy "production, storage, transportation, and utilization" industrial chain is accelerating its layout. The application scenarios of pressure vessels are constantly expanding, and the working environment is becoming increasingly harsh. They generally face extreme conditions such as high temperature, high pressure, strong radiation, vibration, and shock. Moreover, the media are mostly flammable, explosive, toxic, or highly permeable substances. Leakage accidents caused by sealing failure may lead to catastrophic consequences.

[0003] To ensure the safe operation of pressure vessels, leakage tests are required for pressure vessels containing highly hazardous media or those where even minute leaks are unacceptable, and the leakage rate must be controlled within 1×10⁻⁶. -6 Pa・m 3 Below / s, some high-end scenarios (such as hydrogen energy storage and transportation) require a speed of 1×10 -9 Pa・m 3 / s level. However, existing seal detection technologies still have many insurmountable shortcomings, specifically in the following aspects: 1. Traditional bubble method and pressure drop method rely on visual observation or pressure change judgment, which is not suitable for 10 -7 Pa・m 3 Micro-leakage below a certain speed has an extremely high failure rate and cannot penetrate nanoscale pores; ultrasonic testing is easily affected by environmental noise, with a false alarm rate exceeding 15% in industrial settings, and a detection rate of less than 60% for microcracks smaller than 0.5 mm; while helium mass spectrometry leak detection meets sensitivity standards, the equipment cost is as high as several million yuan, helium consumption is expensive, and a vacuum environment is required, making it difficult to popularize in on-site operation and maintenance, mass production, and other scenarios. At the same time, the detection medium has poor compatibility with actual working conditions. Conventional air and nitrogen molecules have large diameters and cannot simulate the permeation characteristics of high-risk media such as hydrogen, leading to frequent false compliance issues of "detection qualified, actual leakage". In addition, it requires long-term pressure holding (30 minutes to 10 days), resulting in low single-station detection efficiency and reliance on manual judgment (such as bubble observation and suction gun scanning), leading to poor consistency and a high risk of fatigue-induced false failures; large pressure vessels (such as the sealing ring of a nuclear power reactor with a diameter of 5 meters) require complete immersion or vacuum treatment, which takes a very long time for preparation and testing, severely restricting the pace of mass production and the tight operation and maintenance requirements of nuclear power plant overhauls; 2. In the differential pressure method, a temperature change of ±0.3℃ can introduce a 0.5% detection error. However, large pressure vessels have poor temperature uniformity, and the thermal expansion and contraction of gas during pressure holding can directly mask the true leakage signal. In addition, factors such as ambient air pressure, humidity fluctuations, electromagnetic interference, vibration, and background noise can cause sensor zero-point drift and a decrease in signal-to-noise ratio, further aggravating the detection error. In complex scenarios such as strong radiation from nuclear power plants and high noise levels at hydrogen refueling stations, the error can even reach more than 20%. Moreover, existing pressure drop, differential pressure, and flow methods can only determine "whether there is a leak," but cannot locate the leak point, requiring additional manpower for secondary investigation, resulting in extremely low maintenance efficiency. Ultrasonic positioning technology, limited by sensor layout and algorithm defects, can only achieve a positioning accuracy of more than 50mm, which is insufficient to meet the requirements for accurate repair. Furthermore, poor sealing of pipelines, joints, and clamps in the detection system can introduce background leakage, which, when superimposed on the actual leakage signal of the container, leads to a significant increase in the false positive rate, especially in high-pressure detection scenarios where the system's own sealing reliability issues are even more prominent. Based on the above problems, we propose a sealing detection system and detection method for pressure vessels. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art, adapt to practical needs, and provide a sealing detection system and method for pressure vessels, so as to solve the problem that the prior art cannot simultaneously meet the requirements of high precision, high efficiency, anti-interference, low cost and full-scenario adaptability.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a sealing detection system for pressure vessels, including a gas source unit, a gas path control unit, a dual differential pressure detection unit, a standard reference tank, an ultrasonic positioning unit, a main control unit, a safety protection unit, and a data management unit, wherein each unit is connected through a gas path and an electrical path to form a closed-loop detection system; The gas source unit includes a high-pressure gas source and a tracer gas source, used to provide the base gas for detection and the tracer gas for micro-leak confirmation; The gas circuit control unit includes a pressure regulating valve, a solenoid valve, a rapid charge / discharge valve, and a precision filter, which are used to realize gas pressure regulation, on / off control, and impurity filtration. The dual differential pressure detection unit includes a high-precision differential pressure sensor, a pressure sensor, and a three-channel temperature sensor array. The three temperature sensors are used to collect the temperature of the pressure vessel under test, the temperature of the standard reference tank, and the ambient temperature, respectively. The standard reference tank and the pressure vessel under test are of the same volume and material, and are used to provide a sealing reference. The ultrasonic positioning unit includes an array of ultrasonic sensors and a noise suppression module, used for locating and identifying the leak point. The main control unit includes a PLC, an edge computing module, and a human-machine interface, which is used to receive detection data, execute temperature compensation algorithms, control the detection process, and output judgment results. The safety protection unit includes an overpressure relief valve, an explosion-proof module, an emergency stop device, and a leakage concentration monitor, which are used to ensure the safety of the detection process. The data management unit is used to store test data, generate test reports, and upload data. Among them, the standard reference tank serves as a sealing reference and is synchronously filled and pressure stabilized with the pressure vessel under test. The dual differential pressure detection unit collects the pressure difference between the two in real time through a high-precision differential pressure sensor to eliminate basic interference caused by ambient air pressure and gas source fluctuations. The three-channel temperature sensor array synchronously collects the real-time temperature of the pressure vessel under test, the standard reference tank, and the environment. The main control unit executes a temperature compensation algorithm based on the ideal gas law to correct the measured differential pressure to the theoretical differential pressure at the reference temperature.

[0006] Preferably, the tracer gas output by the tracer gas source is a hydrogen-nitrogen mixture, wherein the hydrogen volume percentage is 3% to 8%, and the dual differential pressure detection unit is also equipped with a thermally conductive tracer gas sensor for confirming micro-leakage signals.

[0007] Preferably, the temperature compensation algorithm executed by the main control unit is based on the ideal gas law, and the calculated differential pressure after compensation is as follows: in, To compensate for the differential pressure value, To detect the initial absolute temperature, Let k be the real-time absolute temperature of the kth sample. Let K be the pressure of the pressure vessel being measured during the k-th sampling. The standard reference tank pressure is the pressure of the k-th sample.

[0008] Preferably, the main control unit further calculates the leakage rate using a discretization algorithm, and the leakage rate calculation formula is as follows: in, Let k be the leakage rate from the kth sampling. The volume of the pressure vessel being tested. The PLC sampling cycle This is the compensated differential pressure value after the (k-1)th sampling.

[0009] Preferably, the array-type ultrasonic sensor operates at a frequency of 35kHz to 45kHz, the noise suppression module employs an adaptive filtering algorithm to suppress background noise interference in the industrial environment, the leak point positioning accuracy of the ultrasonic positioning unit is ≤10mm, the resolution of the high-precision differential pressure sensor is ≤1Pa, the detection range of the pressure sensor is 0.1MPa to 70MPa, and the temperature compensation algorithm has a temperature adaptation range of 0℃ to 50℃.

[0010] Preferably, it also includes an automatic clamping fixture, which is equipped with a quick-change sealing interface and a sealing self-test module. The sealing self-test module verifies the sealing reliability of the pipeline, joint and fixture through pre-inflation pressure detection.

[0011] Preferably, the human-machine interface is a touch screen, used to display real-time detection curves, leakage rate values, leak location coordinates, and detection results. The data management unit supports both local storage and cloud upload modes, and the detection data is uniquely bound to the pressure vessel under test via barcode or QR code.

[0012] 8. The pressure vessel sealing detection system according to claim 7, wherein the gas circuit control unit is further configured with a one-way valve and a silencer, the one-way valve is used to prevent gas backflow, the silencer is used to reduce exhaust noise, and the safety protection unit further includes a door interlock device, wherein the system cannot start the inflation process when the detection chamber door is not closed.

[0013] The method for testing the sealing performance of pressure vessels is applicable to the sealing testing system for pressure vessels described in any of the above-mentioned methods.

[0014] Preferably, the method includes the following steps: Step S1: System initialization, the main control unit reads the preset detection parameter formula, performs self-check of each unit state, and enters the detection state after confirming that there are no abnormalities; Step S2: Fix the pressure vessel to be tested to the automatic clamping fixture, identify the model and volume information of the pressure vessel to be tested by scanning the barcode or QR code, and the main control unit triggers the automatic clamping fixture to clamp and complete the sealing docking; Step S3: Start the sealing self-test process. The gas circuit control unit opens the pre-charge valve to charge low-pressure gas into the test pipeline, automatic clamping fixture and standard reference tank. Hold the pressure for 10s~30s. The dual differential pressure detection unit detects the pressure change. If the pressure drop value is ≤ the preset self-test threshold, the seal is deemed qualified and proceed to the next step. If it is unqualified, the main control unit triggers an alarm and stops the process. After manual inspection, step S2 is re-executed. Step S4: The gas circuit control unit turns on the high-pressure gas source, adjusts the gas pressure to the preset detection pressure through the pressure regulating valve, and simultaneously and quickly fills the pressure vessel under test and the standard reference tank with gas. After the filling is completed, the filling valve is closed and the pressure stabilization stage is entered to eliminate the elastic deformation of the container and the airflow interference. Step S5: After the pressure stabilization is completed, the dual differential pressure detection unit synchronously collects the pressure of the pressure vessel under test (Pxk), the pressure of the standard reference tank (Psk), and three temperature data (initial absolute temperature T0, real-time absolute temperature Tk). The main control unit calls the temperature compensation algorithm to calculate the compensated differential pressure value (ΔPc). Step S6: Based on the compensated differential pressure value, the main control unit calculates the leakage rate (Qk) using a discretization algorithm and compares the leakage rate (Qk) with a preset leakage rate threshold: if Qk ≤ threshold, the pressure vessel under test is deemed to be sealed and step S9 is executed; if Qk > threshold, it is deemed to be a suspected leak and step S7 is executed. Step S7: The gas circuit control unit shuts off the high-pressure gas source, opens the exhaust valve to purge the gas in the pressure vessel under test and the standard reference tank, and then switches to the tracer gas source to fill the pressure vessel under test with a hydrogen-nitrogen mixture and maintain the pressure for 20s~40s. Step S8: The thermal conductivity tracer gas sensor scans and detects key parts of the pressure vessel under test, such as welds, joints, and sealing surfaces, using a flexible suction gun or a ring scanning probe. If no tracer gas signal is detected, it is determined to be a false leak, and step S9 is executed. If a tracer gas signal is detected, a real leak is confirmed, the ultrasonic positioning unit is activated, and the leak ultrasonic signal is collected by an array of ultrasonic sensors. After processing by the noise suppression module, the leak location coordinates are calculated and output. The main control unit triggers an audible and visual alarm and executes step S9. Step S9: The gas circuit control unit opens the fast exhaust valve to purge the gas in the pressure vessel under test. During the exhaust process, the noise is reduced by the silencer and the one-way valve prevents gas backflow. Step S10: The automatic clamping fixture is released to complete the unloading of the pressure vessel under test; the data management unit binds the test data with the barcode / QR code of the pressure vessel under test, generates a test report, and synchronously stores it in the local database and uploads it to the cloud; Step S11: The main control unit determines whether to continue detection: if yes, return to step S2; if no, the system enters standby mode.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention achieves high-precision, anti-interference detection by setting up a dual differential pressure detection unit, a standard reference tank, and a three-channel temperature sensor array, combined with a temperature compensation algorithm based on the ideal gas law. The standard reference tank has the same volume and material as the container being tested, and synchronous inflation and pressure stabilization can offset the basic interference from ambient gas pressure and gas source fluctuations. The three temperature sensors collect temperature data in real time, and the measured differential pressure is corrected to the theoretical differential pressure at the reference temperature through a compensation formula, eliminating detection errors of more than 0.5% caused by temperature fluctuations of ±0.3℃ or higher. This solves the defects of existing technologies such as large temperature interference and low detection accuracy. Combined with a high-precision differential pressure sensor with a resolution ≤1Pa, it can stably detect 1×10 -6 Pa・m 3 It achieves micro-leakage at the / s level and is compatible with a wide temperature range of 0℃ to 50℃, significantly improving detection consistency.

[0016] 2. This invention achieves the dual effect of accurate detection of micro-leakage and rapid leak location by setting up a high-pressure gas source, a tracer gas source, and an ultrasonic positioning unit, combined with a phased detection mode from coarse to fine. The dual differential pressure detection is used for coarse inspection to quickly screen qualified workpieces, and suspected leaking parts are switched to hydrogen-nitrogen mixture gas with a cost of only 1 / 5 that of helium for fine inspection. The thermal conductivity sensor accurately captures the micro-leakage signal and avoids false judgment. The ultrasonic positioning unit uses a 35kHz~45kHz array sensor and an adaptive filtering algorithm to suppress background noise interference, and the leak location accuracy is ≤10mm. This solves the problems of missed detection of micro-leakage and difficulty in leak location in the prior art. No manual secondary inspection is required, which greatly shortens the maintenance cycle. It is especially suitable for the inspection needs of large pressure vessels and complex structural parts.

[0017] 3. This invention achieves full-process automation and high-efficiency testing by setting up an automatic clamping fixture, a PLC main control unit, and a data management unit, while ensuring data traceability. The automatic clamping fixture is equipped with a quick-change sealing interface and a sealing self-test module, and pre-inflation testing eliminates interference from pipeline and fixture leaks. The main control unit pre-stores multiple sets of parameter formulas. After scanning the workpiece, it automatically triggers the entire process of clamping, inflation, testing, judgment, and unloading without manual intervention. The testing cycle for a single workpiece is shortened to 60s~180s, which is suitable for batch production and compact operation and maintenance needs. The data management unit supports local storage and cloud upload. The test data is uniquely bound to the workpiece barcode / QR code to generate a traceable test report, which meets the regulatory requirements for special equipment and solves the defects of existing technologies such as high dependence on manual labor, low efficiency, and lack of data traceability. Attached Figure Description

[0018] Figure 1 This is a block diagram of the overall structure of the pressure vessel sealing detection system of the present invention; Figure 2 This is a schematic flowchart of the detection method of the present invention; Figure 3This is a schematic diagram showing the connection between the dual differential pressure detection unit of the present invention and the standard reference tank; Figure 4 This is a logic block diagram of the temperature compensation algorithm of the present invention. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments: Example 1

[0020] In this embodiment, the pressure vessel under test has a volume of 0.01 m³. 3 A 10L hydrogen storage cylinder, tested at a pressure of 35MPa, with a leakage rate threshold of 1×10⁻⁶. -6 Pa・m 3 / s, ambient temperature 25℃ (initial absolute temperature T0=298.15K), PLC sampling period Δt=1s.

[0021] A pressure vessel sealing detection system includes a gas source unit, a gas path control unit, a dual differential pressure detection unit, a standard reference tank, an ultrasonic positioning unit, a main control unit, a safety protection unit, a data management unit, and an automatic clamping fixture.

[0022] The high-pressure gas source of the gas source unit uses nitrogen, and the tracer gas source outputs a hydrogen-nitrogen mixture (hydrogen volume percentage 5%). The pressure regulating valve of the gas circuit control unit is an electro-proportional pressure regulating valve with an adjustment range of 0.1MPa~70MPa. The rapid charge / discharge valve uses a high-flow electromagnetic ball valve with exhaust noise ≤75dB. The dual differential pressure detection unit features a high-precision differential pressure sensor with a resolution of 0.5Pa, a pressure sensor range of 0~40MPa, a temperature sensor array accuracy of ±0.1℃, and a thermal conductivity tracer gas sensor with a detection limit of 1×10⁻⁶. -7 Pa・m 3 / s; Standard reference tank volume 0.01m³ 3 The material is the same as the hydrogen storage cylinder being tested (316L stainless steel); the ultrasonic positioning unit has an array of 8 ultrasonic sensors with a working frequency of 40kHz, and the noise suppression module uses the LMS adaptive filtering algorithm, with a positioning accuracy of ±5mm; the main control unit uses a Siemens S7-1500 PLC, an NVIDIA Jetson Nano edge computing module, and a 10-inch touchscreen; the overpressure relief valve of the safety protection unit is set to a pressure of 38MPa, and the hydrogen detection lower limit of the leakage concentration monitor is 0.1%VOL; the data management unit has a local storage capacity of 1TB and supports 4G / 5G cloud upload; the quick-change sealing interface of the automatic clamping fixture uses fluororubber seals, the pre-charge pressure of the sealing self-test module is 0.2MPa, the pressure holding time is 20s, and the self-test threshold is 0.005MPa.

[0023] The specific steps of the detection method using the above system are as follows: Step S1: System initialization, the main control unit reads the preset detection parameters (detection pressure 35MPa, pressure holding time 60s, leakage rate threshold 1×10). -6 Pa・m 3 / s, temperature compensation coefficient), self-check the sensor, actuator and air circuit sealing, and enter the test state after confirming that there are no abnormalities; Step S2: Secure the hydrogen storage cylinder to be tested to the automatic clamping fixture, and identify the cylinder model and volume information (0.01m³) by scanning the QR code. 3 The main control unit triggers the automatic clamping fixture to clamp and complete the sealing docking; Step S3: Start the sealing self-test process. The gas circuit control unit opens the pre-charge valve and charges 0.2MPa low-pressure nitrogen into the test pipeline, automatic clamping fixture and standard reference tank. Hold the pressure for 20s. The dual differential pressure detection unit detects the pressure change. If the pressure drop value is 0.002MPa ≤ self-test threshold of 0.005MPa, the seal is deemed qualified and proceed to the next step. Step S4: The gas circuit control unit turns on the high-pressure gas source and adjusts the nitrogen pressure to 35MPa through the pressure regulating valve. It then simultaneously and rapidly fills the hydrogen energy storage cylinder under test and the standard reference tank with gas for 45 seconds. After the filling is completed, the filling valve is closed, and the pressure stabilization stage is entered for 60 seconds to eliminate container elastic deformation and airflow interference. Step S5: After the pressure stabilization is completed, the dual differential pressure detection unit synchronously collects the pressure of the hydrogen energy storage cylinder under test (Pxk), the pressure of the standard reference tank (Psk), and three-channel temperature data (real-time absolute temperature Tk=298.35K). The main control unit calls the temperature compensation algorithm to calculate the compensated differential pressure value ΔPc=298.15 / 298.35×(35000000Pa-34999998Pa)=1.998Pa; Step S6: The main control unit calculates the leakage rate Qk=0.01m using a discretization algorithm. 3 ×(1.998Pa-1.898Pa) / 1s=1×10 -3 Pa・m 3 / s, Qk>leakage rate threshold 1×10 -6 Pa・m 3 / s, is determined to be a suspected leak, and step S7 is executed; Step S7: The gas circuit control unit shuts off the high-pressure gas source, opens the exhaust valve to purge the nitrogen in the hydrogen energy storage cylinder under test and the standard reference cylinder (exhaust time 30s), and then switches to the tracer gas source to fill the hydrogen energy storage cylinder under test with 5% hydrogen-nitrogen mixture and maintain the pressure for 30s; Step S8: The thermal conductivity tracer gas sensor scans and detects key parts such as gas cylinder welds and valve joints using a flexible suction gun. If a tracer gas signal is detected, a real leak is confirmed. The ultrasonic positioning unit is activated, and the array ultrasonic sensor collects the leak ultrasonic signal. After processing by the noise suppression module, the coordinates of the leak location (gas cylinder shoulder weld, X=120mm, Y=80mm) are output. The main control unit triggers an audible and visual alarm and executes step S9. Step S9: The gas circuit control unit opens the fast exhaust valve to empty the 5% hydrogen-nitrogen mixture in the hydrogen energy storage cylinder to be tested. During the exhaust process, the silencer reduces the noise to 72dB, and the one-way valve prevents gas backflow. Step S10: The automatic clamping fixture is released, completing the unloading of the hydrogen storage cylinder to be tested; the data management unit will process the detection data (pressure, temperature, differential pressure, leakage rate 1×10⁻⁶). -3 Pa・m 3 The system binds the gas cylinder's QR code to the gas cylinder's location coordinates (e.g., leak location coordinates), generates a test report, and simultaneously stores it in the local database and uploads it to the cloud. Step S11: The main control unit prompts whether to continue the detection. If "Yes" is selected, return to step S2; if "No" is selected, the system enters standby mode. Example 2

[0024] In this embodiment, the pressure vessel under test has a volume of 1m³. 3 The industrial gas storage tank has a test pressure of 1.6 MPa and a leakage rate threshold of 5 × 10⁻⁶. -6 Pa・m 3 / s, ambient temperature 20℃ (initial absolute temperature T0=293.15K), PLC sampling period Δt=2s.

[0025] The system configuration is basically the same as in Example 1, except that the standard reference tank 4 has a volume of 1m³. 3 The material is the same as that of the industrial gas storage tank being tested (Q345R steel plate); the ultrasonic positioning unit 5 has 16 array-type ultrasonic sensors 51 with a positioning accuracy of ±8mm; the detection pressure is 1.6MPa, the pre-charge pressure is 0.3MPa, the pressure holding time is 30s, and the pressure stabilization time is 45s.

[0026] The detection method and steps are the same as in Example 1, wherein step S5 calculates the compensated differential pressure value ΔPc = 293.15 / 293.35 × (1600000Pa - 1599999.5Pa) = 0.499Pa; step S6 calculates the leakage rate Qk = 1m 3 ×(0.499Pa-0.497Pa) / 2s=1×10 -3 Pa・m 3 / s, Qk≤leakage rate threshold 5×10 -6 Pa・m 3 / s, if the seal is deemed qualified, proceed directly to steps S9~S11, and data management unit 8 generates a qualified inspection report and stores and uploads it.

[0027] As can be seen from the above embodiments, the pressure vessel sealing detection system and its detection method of the present invention can achieve high-precision sealing detection of pressure vessels of different volumes and pressure levels, effectively solve many defects of the prior art, and have good practicality and promotion value.

[0028] The embodiments disclosed in this invention are preferred embodiments, but are not limited thereto. Those skilled in the art can easily understand the spirit of this invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of this invention, they are all within the protection scope of this invention.

Claims

1. A sealing detection system for pressure vessels, characterized in that, It includes a gas source unit, a gas path control unit, a dual differential pressure detection unit, a standard reference tank, an ultrasonic positioning unit, a main control unit, a safety protection unit, and a data management unit. Each unit is connected through a gas path and an electrical circuit to form a closed-loop detection system. The gas source unit includes a high-pressure gas source and a tracer gas source, used to provide the base gas for detection and the tracer gas for micro-leak confirmation; The gas circuit control unit includes a pressure regulating valve, a solenoid valve, a rapid charge / discharge valve, and a precision filter, which are used to realize gas pressure regulation, on / off control, and impurity filtration. The dual differential pressure detection unit includes a high-precision differential pressure sensor, a pressure sensor, and a three-channel temperature sensor array. The three temperature sensors are used to collect the temperature of the pressure vessel under test, the temperature of the standard reference tank, and the ambient temperature, respectively. The standard reference tank and the pressure vessel under test are of the same volume and material, and are used to provide a sealing reference. The ultrasonic positioning unit includes an array of ultrasonic sensors and a noise suppression module, used for locating and identifying the leak point. The main control unit includes a PLC, an edge computing module, and a human-machine interface, which is used to receive detection data, execute temperature compensation algorithms, control the detection process, and output judgment results. The safety protection unit includes an overpressure relief valve, an explosion-proof module, an emergency stop device, and a leakage concentration monitor, which are used to ensure the safety of the detection process. The data management unit is used to store test data, generate test reports, and upload data. Among them, the standard reference tank serves as a sealing reference and is synchronously filled and pressure stabilized with the pressure vessel under test. The dual differential pressure detection unit collects the pressure difference between the two in real time through a high-precision differential pressure sensor to eliminate basic interference caused by ambient air pressure and gas source fluctuations. The three-channel temperature sensor array synchronously collects the real-time temperature of the pressure vessel under test, the standard reference tank, and the environment. The main control unit executes a temperature compensation algorithm based on the ideal gas law to correct the measured differential pressure to the theoretical differential pressure at the reference temperature.

2. The pressure vessel sealing detection system according to claim 1, characterized in that, The tracer gas output by the tracer gas source is a hydrogen-nitrogen mixture, wherein the volume percentage of hydrogen is 3% to 8%. The dual differential pressure detection unit is also equipped with a thermally conductive tracer gas sensor for confirming micro-leakage signals.

3. The pressure vessel sealing detection system according to claim 2, characterized in that, The temperature compensation algorithm executed by the main control unit is based on the ideal gas law, and the calculated differential pressure after compensation is as follows: in, To compensate for the differential pressure value, To detect the initial absolute temperature, Let k be the real-time absolute temperature of the kth sample. Let K be the pressure of the pressure vessel being measured during the k-th sampling. The standard reference tank pressure is the pressure of the k-th sample.

4. The pressure vessel sealing detection system and detection method according to claim 3, characterized in that, The main control unit also calculates the leakage rate using a discretization algorithm. The leakage rate calculation formula is as follows: in, Let k be the leakage rate from the kth sampling. The volume of the pressure vessel being tested. The PLC sampling cycle This is the compensated differential pressure value after the (k-1)th sampling.

5. The pressure vessel sealing detection system according to claim 4, characterized in that, The array-type ultrasonic sensor operates at a frequency of 35kHz to 45kHz. The noise suppression module employs an adaptive filtering algorithm to suppress background noise interference in industrial settings. The leak location accuracy of the ultrasonic positioning unit is ≤10mm. The high-precision differential pressure sensor has a resolution of ≤1Pa. The pressure sensor has a detection range of 0.1MPa to 70MPa. The temperature compensation algorithm has a temperature adaptation range of 0℃ to 50℃.

6. The pressure vessel sealing detection system according to claim 5, characterized in that, It also includes an automatic clamping fixture, which is equipped with a quick-change sealing interface and a sealing self-testing module. The sealing self-testing module verifies the sealing reliability of pipelines, joints and fixtures through pre-inflation pressure detection.

7. The pressure vessel sealing detection system according to claim 6, characterized in that, The human-machine interface is a touch screen, which is used to display real-time detection curves, leakage rate values, leak location coordinates and detection results. The data management unit supports both local storage and cloud upload modes, and the detection data is uniquely bound to the pressure vessel under test through a barcode or QR code.

8. The pressure vessel sealing detection system according to claim 7, characterized in that, The gas circuit control unit is also equipped with a one-way valve and a silencer. The one-way valve is used to prevent gas backflow, and the silencer is used to reduce exhaust noise. The safety protection unit also includes a door interlock device. When the detection hatch is not closed, the system cannot start the inflation process.

9. A method for testing the sealing performance of a pressure vessel, characterized in that, A sealing detection system applicable to the pressure vessel according to any one of claims 1-8.

10. The method for testing the sealing performance of a pressure vessel according to claim 9, characterized in that, Includes the following steps: Step S1: System initialization, the main control unit reads the preset detection parameter formula, performs self-check of each unit state, and enters the detection state after confirming that there are no abnormalities; Step S2: Fix the pressure vessel to be tested to the automatic clamping fixture, identify the model and volume information of the pressure vessel to be tested by scanning the barcode or QR code, and the main control unit triggers the automatic clamping fixture to clamp and complete the sealing docking; Step S3: Start the sealing self-test process. The gas circuit control unit opens the pre-charge valve to charge low-pressure gas into the test pipeline, automatic clamping fixture and standard reference tank. Hold the pressure for 10s~30s. The dual differential pressure detection unit detects the pressure change. If the pressure drop value is ≤ the preset self-test threshold, the seal is deemed qualified and proceed to the next step. If it is unqualified, the main control unit triggers an alarm and stops the process. After manual inspection, step S2 is re-executed. Step S4: The gas circuit control unit turns on the high-pressure gas source, adjusts the gas pressure to the preset detection pressure through the pressure regulating valve, and simultaneously and quickly fills the pressure vessel under test and the standard reference tank with gas. After the filling is completed, the filling valve is closed and the pressure stabilization stage is entered to eliminate the elastic deformation of the container and the airflow interference. Step S5: After the pressure stabilization is completed, the dual differential pressure detection unit synchronously collects the pressure of the pressure vessel under test (Pxk), the pressure of the standard reference tank (Psk), and three temperature data (initial absolute temperature T0, real-time absolute temperature Tk). The main control unit calls the temperature compensation algorithm to calculate the compensated differential pressure value (ΔPc). Step S6: Based on the compensated differential pressure value, the main control unit calculates the leakage rate (Qk) using a discretization algorithm and compares the leakage rate (Qk) with a preset leakage rate threshold: if Qk ≤ threshold, the pressure vessel under test is deemed to be sealed and step S9 is executed; if Qk > threshold, it is deemed to be a suspected leak and step S7 is executed. Step S7: The gas circuit control unit shuts off the high-pressure gas source, opens the exhaust valve to purge the gas in the pressure vessel under test and the standard reference tank, and then switches to the tracer gas source to fill the pressure vessel under test with a hydrogen-nitrogen mixture and maintain the pressure for 20s~40s. Step S8: The thermal conductivity tracer gas sensor scans and detects key parts of the pressure vessel under test, such as welds, joints, and sealing surfaces, using a flexible suction gun or a ring scanning probe. If no tracer gas signal is detected, it is determined to be a false leak, and step S9 is executed. If a tracer gas signal is detected, a real leak is confirmed, the ultrasonic positioning unit is activated, and the leak ultrasonic signal is collected by an array of ultrasonic sensors. After processing by the noise suppression module, the leak location coordinates are calculated and output. The main control unit triggers an audible and visual alarm and executes step S9. Step S9: The gas circuit control unit opens the fast exhaust valve to purge the gas in the pressure vessel under test. During the exhaust process, the noise is reduced by the silencer and the one-way valve prevents gas backflow. Step S10: The automatic clamping fixture is released to complete the unloading of the pressure vessel under test; the data management unit binds the test data with the barcode / QR code of the pressure vessel under test, generates a test report, and synchronously stores it in the local database and uploads it to the cloud; Step S11: The main control unit determines whether to continue detection: if yes, return to step S2; if no, the system enters standby mode.

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