A device and control method for detecting and controlling the airtightness of pipes in subway cars.

Abstract

This invention discloses a device and control method for detecting the airtightness of subway car pipes, relating to the field of rail transit vehicle maintenance technology. The detection device includes a gas supply pipe, a first pressure sensor, a pressure regulating device, a gas storage unit, a detection unit, and a control unit. The gas supply pipe is connected to a gas source; the first pressure sensor is mounted on the gas supply pipe; the pressure regulating device is mounted on the gas supply pipe to regulate the gas pressure; the gas storage unit is connected to the pressure regulating device; the detection unit includes a second pressure sensor and a pressure gauge, connected to the gas outlet pipe of the gas storage unit, and has an output interface; the control unit is electrically connected to the first pressure sensor, the pressure regulating device, and the detection unit. This invention solves the problems of existing airtightness detection devices relying on manual operation for gas filling and having a low degree of automation.

Description

Technical Field

[0001] The present invention relates to the technical field of rail transit vehicle maintenance, and particularly to an airtightness detection device and control method for subway carriages' pipelines. Background Art

[0002] The braking system of rail transit vehicles is the core guarantee for the safe operation of vehicles. The sealing performance of the braking pipeline system directly affects the reliability of vehicle braking and driving safety. If the sealing performance of the braking pipeline system is poor, it may cause the vehicle to fail to brake and stop in time, leading to serious safety accidents. Therefore, during the manufacturing and maintenance processes of rail transit vehicles, airtightness detection of the braking pipelines is an essential process.

[0003] Currently, the pressure drop method is a relatively commonly used method for pipeline airtightness detection. Its basic principle is: filling a certain pressure of gas into the pipeline system to be tested, closing the gas source and maintaining the pressure for a period of time, and judging whether there is leakage in the pipeline system by comparing the pressure difference between the starting and ending moments of pressure maintenance.

[0004] In the prior art, Chinese Patent Application No. 202310996043.9 discloses a pressure maintenance device for traffic pipelines. It includes a frame, an air intake unit, and a pressure maintenance unit; the air intake unit has an air intake port and a cut-off cock; the pressure maintenance unit includes a first solenoid valve, a booster pump, a working air cylinder, a second solenoid valve, and a first pressure sensor connected in sequence, and the working air cylinder is also connected with a second pressure sensor; a controller is provided on the frame, which is electrically connected to the cut-off cock, the first solenoid valve, the booster pump, the second solenoid valve, the first pressure sensor, and the second pressure sensor.

[0005] However, the above-mentioned prior art device still has the following deficiencies while solving problems: such as being fixedly installed and unable to move; manually recording data and unable to automatically archive; unable to monitor the leakage rate in real time during the detection process; lacking identity verification and electronic signature functions; not setting up a structure to prevent small animals from intruding.

[0006] In addition, there is still room for further optimization in the control method of existing airtightness detection devices. For example, most existing devices only calculate the total pressure drop and judge whether it is qualified after the pressure maintenance ends, and cannot respond immediately to rapid leaks during the pressure maintenance process, resulting in too long ineffective waiting time. Also, the test parameters of existing devices are usually fixed values or set manually, and cannot be dynamically adjusted according to the operating state of the equipment or the type of the test object. Moreover, after the test is judged unqualified, usually, the operator needs to manually restart the test, and the detection efficiency is low.

[0007] Therefore, how to provide an airtightness detection device for subway carriages' pipelines with flexible movement, intelligent operation, traceable data, and higher safety, as well as the corresponding control method, has become a technical problem that needs to be urgently solved by those skilled in the art. Summary of the Invention

[0008] This invention provides a device and control method for detecting the air tightness of pipelines in subway cars, which can solve the problems of existing air tightness detection devices relying on manual operation for air filling and cutting off, and having a low degree of automation.

[0009] To address the above problems, the present invention provides a device for detecting the airtightness of pipes in subway cars, comprising: A gas supply pipe, the input end of which is connected to a gas source; A first pressure sensor is installed on the gas delivery pipe, and the first pressure sensor detects the gas pressure of the gas delivery pipe; A pressure regulating device is installed on the gas transmission pipe, and the pressure regulating device regulates the gas pressure of the gas transmission pipe; A gas storage unit is installed on the gas transmission pipe, and the gas inlet of the gas storage unit is connected to the gas outlet of the pressure regulating device. The detection unit includes a second pressure sensor and a pressure gauge. The detection end of the second pressure sensor is connected to the gas outlet pipeline of the gas storage unit, and the pressure gauge is connected in parallel to the gas outlet pipeline. An output interface is provided at one end of the detection unit. The control unit is electrically connected to the first pressure sensor, the pressure regulating device, and the detection unit.

[0010] The present invention provides a subway car pipe airtightness testing device, which, compared with the prior art, has the following beneficial effects, but is not limited to: By setting up a control unit electrically connected to the air pump, pressure sensor, pressure regulator, and detection unit, centralized automated control of inflation, pressure holding, and pressure acquisition is achieved, eliminating the need for manual monitoring and shutdown, thus significantly improving detection efficiency and accuracy. At the same time, the stable output pressure of the gas storage unit, the flexible adjustment of the gas pipeline pressure by the pressure regulator, and the coordinated monitoring by the pressure sensor and pressure gauge in the detection unit ensure the safety and reliability of the detection process and the readability of the data, effectively solving the problems of traditional detection methods that rely on manual operation, have low automation, and poor detection consistency.

[0011] Preferably, the pressure regulating device includes: A pressure boosting valve is installed on the gas transmission pipe; An overflow valve; its input end is connected to the output end of the booster valve through the gas supply pipe, and the output end of the overflow valve is connected to the atmosphere or return air pipeline, used to automatically open and release pressure when the system pressure exceeds the set value.

[0012] Preferably, an air filter, an electromagnetic shut-off valve, and a pressure boosting valve are sequentially arranged on the gas supply pipe along the airflow direction.

[0013] Preferably, it also includes a mobile trolley, on which the gas supply pipe, the first pressure sensor, the pressure regulating device, the gas storage unit, the detection unit and the control unit are all installed; The mobile trolley has a four-wheel structure, and the front wheels of the mobile trolley are equipped with a locking mechanism; The mobile vehicle has a closed outer shell, which is equipped with a protective net or sealing structure to prevent small animals from entering.

[0014] Preferably, this application also provides a control method, comprising the following steps: Step S1: Start the self-test program to check the sealing of the device's own pipelines. If the self-test is qualified, it will enter the standby state. Step S2: Receive the test parameters input by the user, including the target holding pressure value P0, the holding time T0, and the qualified pressure drop threshold P. th ; Step S3: Control the opening of the electromagnetic shut-off valve and the booster valve so that the workshop air source is purified and boosted before being supplied to the pipeline of the test vehicle, and at the same time collect the pressure value P fed back by the first pressure sensor in real time. Step S4: When P reaches P0±ΔP, the electromagnetic shut-off valve is automatically closed to stop inflation, where ΔP is the allowable deviation; Step S5: Enter the pressure holding stage, continuously monitor the pressure value P and record the time. When the pressure holding time reaches T0, calculate the difference between the pressure value at the beginning of the pressure holding and the pressure value at the end of the pressure holding. This difference is the pressure drop value. Step S6: Compare the pressure drop value with the acceptable pressure drop threshold P th Comparison: Step S7: Automatically store the experimental process data and generate an electronic record sheet.

[0015] The control method provided by this invention has, but is not limited to, the following beneficial effects compared to the prior art: After ensuring the device's own sealing through a self-testing procedure, it automatically receives the target pressure, pressure holding time, and qualified pressure drop threshold set by the user. After inflating to the target pressure, it automatically cuts off the gas supply and enters the pressure holding stage, requiring no manual intervention throughout the process. After the pressure holding is completed, it automatically calculates the pressure drop value and compares it with the preset threshold. At the same time, it automatically stores the test process data and generates an electronic record sheet, thus realizing intelligent control of the entire process from parameter input, inflation, pressure holding, judgment to data archiving. This not only avoids the errors and inefficiencies caused by manual operation, but also ensures the traceability of test results, significantly improving the automation level and operational standardization of subway car pipeline airtightness testing.

[0016] Preferably, step S2 further includes an identity verification sub-step: before inputting test parameters, the operator is identified, and the test parameters can only be received after successful verification; and the operator's electronic signature is associated with the generated test record table.

[0017] Preferably, in step S5, the pressure drop rate is judged in real time during the pressure holding period. If the pressure drop exceeds the preset rate threshold per unit time, an audible and visual alarm is triggered in advance and the test is terminated.

[0018] Preferably, in step S6, if the pressure drop value is ≤ the acceptable pressure drop threshold P th If the test is passed, a green light will illuminate to indicate that the test is successful, and a test record form will be automatically generated. If the pressure drop value is greater than the acceptable pressure drop threshold P th If the test fails, the test is deemed unqualified, an audible and visual alarm is triggered, and the unqualified data is recorded. When the test is deemed unqualified, the device automatically records the pressure value and corresponding time at the moment of leakage, and automatically jumps to step S3 to re-perform the pressure holding test, and records the number of retests; if the test still fails after a preset number of retests, the test is stopped and an alarm is triggered.

[0019] Preferably, after step S7, a pressure relief step is further included: automatically controlling the electromagnetic shut-off valve or manually operating the pressure relief valve to release the pressure in the system pipeline.

[0020] Preferably, the self-test procedure in step S1 specifically includes: performing a sealing test on the piping system of the device body to ensure that the device itself has no leaks before entering the standby state. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall structure of the subway car pipeline airtightness testing device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the internal overall structure of a subway car pipeline airtightness testing device according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the pressure regulating device and detection unit according to an embodiment of the present invention; Figure 4 This is a flowchart illustrating the method for detecting and controlling the airtightness of subway car pipes according to an embodiment of the present invention.

[0023] Explanation of reference numerals in the attached figures: 100. Mobile trolley; 110. Gas supply pipe; 120. First pressure sensor; 130. Pressure regulating device; 131. Pressure boosting valve; 132. Overflow valve; 140. Gas storage unit; 150. Detection unit; 151. Second pressure sensor; 152. Pressure gauge; 160. Control unit; 170. Air filter; 180. Electromagnetic shut-off valve. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, specific embodiments of this application are described clearly and completely below with reference to the accompanying drawings. It should be understood that the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments described in this application without creative effort will fall within the scope of protection of this application.

[0025] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the specification of this application is for the purpose of describing specific embodiments only and is not intended to limit this application; the terms "comprising," "including," "having," "containing," "comprise," etc., in the specification, claims, and accompanying drawings of this application are open-ended terms, indicating that a method comprises one or more steps, or an apparatus comprises one or more elements, but not excluding the inclusion of other steps or elements. The terms "first," "second," etc., in the specification, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0026] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0027] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0028] It should be emphasized that when the term "comprising / including" is used in this specification, it is used to explicitly indicate the presence of the stated feature, integer, step, or component, but does not exclude the presence or addition of one or more other features, integers, steps, parts, or groups of features, integers, steps, or parts.

[0029] like Figures 1 to 4 As shown in the figure, an embodiment of the present invention provides a subway car pipeline airtightness testing device, including a gas supply pipe 110, a first pressure sensor 120, a pressure regulating device 130, a gas storage unit 140, a detection unit 150, and a control unit 160. The input end of the gas supply pipe 110 is connected to a gas source; the first pressure sensor 120 is disposed on the gas supply pipe 110 and detects the gas pressure of the gas supply pipe 110; the pressure regulating device 130 is disposed on the gas supply pipe 110 and regulates the gas pressure of the gas supply pipe 110; the gas storage unit 140, the detection unit 150, and the control unit 160 are all included. A gas unit 140 is disposed on the gas supply pipe 110, and the gas inlet of the gas storage unit 140 is connected to the gas outlet of the pressure regulating device 130; the detection unit 150 includes a second pressure sensor 151 and a pressure gauge 152, the detection end of the second pressure sensor 151 is connected to the gas outlet pipe of the gas storage unit 140, the pressure gauge 152 is connected in parallel to the gas outlet pipe, and an output interface is provided at one end of the detection unit 150; the control unit 160 is electrically connected to the first pressure sensor 120, the pressure regulating device 130, and the detection unit 150.

[0030] In this embodiment, an externally configured air source is connected to an air pump, which is connected to the workshop air. Preferably, the air source can be an inert gas or compressed air. The output end of the air pump is connected to an air delivery pipe 110, which is made of pressure-resistant rubber or stainless steel. In this embodiment, it is made of pressure-resistant rubber.

[0031] The gas pipeline 110 is equipped with a first pressure sensor 120 and a pressure regulating device 130. The pressure regulating device 130 is used to regulate the gas pressure in the gas pipeline 110. The pressure regulating device 130 may include components such as an electromagnetic shut-off valve 180, an overflow valve 132, and a pressure boosting valve 131.

[0032] The air inlet of the air storage unit 140 is connected to the air outlet of the pressure regulating device 130. The air storage unit 140 uses a 50L air storage cylinder to store the air in the workshop after it has been regulated by the pressure regulating device 130 and to provide a stable air source.

[0033] The second pressure sensor 151 of the detection unit 150 detects the gas pressure discharged from the gas storage unit 140. At the same time, one end of the detection unit 150 is provided with an output interface for connecting to the brake line or air duct of the subway car being tested.

[0034] It is worth noting that in this embodiment, the second pressure sensor 151 is electrically connected to the control unit 160 to collect pressure signals in real time and transmit them to the control unit 160 to realize automatic inflation, pressure holding monitoring and pressure drop calculation; while the pressure gauge 152 is connected in parallel to the pipeline to display the pressure value on site for manual reading and verification by the operator. The two complement each other, taking into account the convenience of automated detection and the reliability of manual verification, and avoiding the failure of detection results due to the failure of a single sensor.

[0035] The control unit 160 uses an industrial computer to receive sensor signals and control the actuators to achieve functions such as automatic inflation, pressure holding, detection, alarm, and data recording.

[0036] In this embodiment, the pressure regulating device 130 includes a booster valve 131 and an overflow valve 132. The booster valve 131 is disposed on the gas supply pipe 110. The input end of the overflow valve 132 is connected to the output end of the booster valve 131 through the gas supply pipe 110. The output end of the overflow valve 132 is connected to the atmosphere or the return air pipeline, and is used to automatically open and release pressure when the system pressure exceeds the set value.

[0037] In this embodiment, the booster valve 131 employs an air-driven booster with a boost ratio of 2, an inlet pressure of 1–8 bar, an outlet pressure of 16 bar, and a maximum flow rate of 1000 L / min. This booster valve 131 is installed on the gas supply pipe 110 and is used to boost the workshop gas source pressure to the required value. The input end of the overflow valve 132 is connected to the input end of the booster valve 131 via the gas supply pipe 110. The input end of the overflow valve 132 is connected to the atmosphere or a return air pipeline. The pressure regulation range of the overflow valve 132 is 0.007 MPa–3.45 MPa. The valve body is made of bronze, and the valve core is made of stainless steel.

[0038] When the system pressure exceeds the set value of the relief valve 132, the relief valve 132 automatically opens, releasing excess gas to the atmosphere or return air duct, thereby protecting downstream pipelines and equipment from overpressure damage. The set value of the relief valve 132 is usually higher than the test target pressure, typically limiting the maximum pressure to 10%-20% above the working pressure. When a malfunction of the booster valve 131 or upstream control component causes an abnormal pressure increase, the relief valve 132 immediately activates, providing safety protection.

[0039] In this embodiment of the application, an air filter 170, an electromagnetic shut-off valve 180 and a pressure boosting valve 131 are sequentially arranged on the air supply pipe 110 along the airflow direction.

[0040] In this embodiment, an air filter 170 is first installed on the air supply pipe 110 along the air source inflow direction. This filter has a filtration accuracy of 0.025mm to 0.05mm and a filtration efficiency of over 90%. The air filter 170 is used to trap liquid and solid impurities in the compressed air, ensuring the cleanliness of the air entering subsequent pipelines. The outlet of the air filter 170 is connected to an electromagnetic shut-off valve 180. The electromagnetic shut-off valve 180 can be any suitable model known in the art. As a specific embodiment, the nominal diameter of the electromagnetic shut-off valve 180 is DN3 to DN100, and the connection method is threaded connection, flange connection, or welded connection. The valve body material is SS304 or brass, the working pressure range is 0.05 to 1.6MPa, and the medium temperature range is -10℃ to 130℃. Those skilled in the art understand that the above parameters are merely examples and do not constitute a limitation on the scope of protection of this invention.

[0041] The electromagnetic shut-off valve 180 is controlled by the control unit 160 to achieve automatic inflation and shut-off. The outlet of the electromagnetic shut-off valve 180 is connected to the pressure booster valve 131, which further pressurizes the purified compressed air to the pressure required for the test. The above sequential connection ensures that impurities are filtered first, then the on / off is controlled by the electromagnetic valve, and finally the pressure is boosted for output, avoiding damage to the electromagnetic valve and pressure booster valve 131 caused by impurities, while ensuring control accuracy.

[0042] In this embodiment of the application, a mobile cart 100 is also included. The air supply pipe 110, the first pressure sensor 120, the pressure regulating device 130, the air storage unit 140, the detection unit 150, and the control unit 160 are all installed on the mobile cart 100. The mobile cart 100 has a four-wheel structure, and the front wheels of the mobile cart 100 are equipped with a locking mechanism. The mobile cart 100 has a closed shell, and the shell is provided with a protective net or sealing structure to prevent small animals from entering.

[0043] In this embodiment, the entire airtightness testing device is integrated onto a mobile trolley 100, facilitating movement between different workstations within the depot. The mobile trolley 100 employs a four-wheel structure, with two rear directional wheels and two front swivel wheels. Locking mechanisms are installed on the front wheels; when the trolley reaches the predetermined position, the operator depresses the locking mechanisms, locking the front wheels and preventing accidental movement during testing. The trolley body has a closed outer shell, with all internal components housed within it. Protective netting, specifically metal mesh with an aperture no larger than 10mm, is installed at the bottom, side vents, and pipeline inlets / outlets of the outer shell to prevent small animals from entering.

[0044] This application embodiment also provides a control method, which is executed by a subway car pipe airtightness detection device, and includes the following steps: Step S1: Start the self-test program to check the sealing of the device's own pipelines. If the self-test is qualified, it will enter the standby state. Step S2: Receive the test parameters input by the user, including the target holding pressure value P0, the holding time T0, and the qualified pressure drop threshold P. th ; Step S3: Control the opening of the electromagnetic shut-off valve 180 and the pressure boosting valve 131 so that the workshop air source is purified and pressurized before being supplied to the pipeline of the test vehicle. At the same time, the pressure value P fed back by the first pressure sensor 120 is collected in real time. Step S4: When P reaches P0±ΔP, the electromagnetic shut-off valve 180 is automatically closed to stop inflation, where ΔP is the allowable deviation; Step S5: Enter the pressure holding stage, continuously monitor the pressure value P and record the time. When the pressure holding time reaches T0, calculate the difference between the pressure value at the beginning of the pressure holding and the pressure value at the end of the pressure holding. This difference is the pressure drop value. Step S6: Compare the pressure drop value with the acceptable pressure drop threshold P th Comparison: Step S7: Automatically store the experimental process data and generate an electronic record sheet.

[0045] In this embodiment, the control method is as follows: In step S1, the control unit 160 controls the electromagnetic shut-off valve 180 and the pressure boosting valve 131 to perform a sealing test on the piping system of the device itself. That is, a certain pressure of gas is injected into the internal piping of the device, and after closing all valves, the pressure change is monitored. If the pressure drop is within the allowable range, the self-test is deemed qualified and the device enters the standby state; if the self-test fails, the device reports an error and prohibits the test.

[0046] In step S2, the operator inputs the target holding pressure value P0 via the touchscreen. P0 can be set to 9.0 bar, the holding time T0 can be set to 30 minutes, and the acceptable pressure drop threshold P. th P th It can be set to 0.1 bar, and the control unit 160 stores these parameters in memory.

[0047] In step S3, the control unit 160 opens the electromagnetic shut-off valve 180. The workshop air source, after passing through the air filter 170, electromagnetic shut-off valve 180, booster valve 131, and air storage unit 140, inflates the pipeline of the vehicle under test. At the same time, the second pressure sensor 151 installed on the air outlet pipeline of the air storage unit 140 collects the pressure value P in real time and feeds it back to the control unit 160.

[0048] In step S4, the control unit 160 compares the real-time pressure P with the target pressure P0. When P reaches P0±ΔP, where ΔP is the allowable deviation, for example, when ΔP=0.20bar, the control unit 160 automatically closes the electromagnetic shut-off valve 180 and stops inflation.

[0049] In step S7, the control unit 160 automatically stores the data of the entire test process on the local hard disk and generates an electronic record sheet, which supports subsequent export and printing. The data includes pressure-time curves, starting pressure, ending pressure, pressure drop value, judgment results, etc.

[0050] In this embodiment of the application, step S2 further includes an identity verification sub-step: before inputting test parameters, the operator is identified, and the test parameters can only be received after the verification is successful; and the operator's electronic signature is associated in the generated test record table.

[0051] In this embodiment, authentication can be achieved by entering the employee ID and password via a touchscreen, or by swiping an IC card, fingerprint recognition, or other methods. The control unit 160 associates and stores the operator's identity information with the test parameters. This authentication and electronic signature function ensures that the results of each airtightness test can be traced back to the specific operator, meeting the rail transit industry's management requirements for traceability of the maintenance process, and avoiding potential issues of missing or forged signatures when manually filling out record forms.

[0052] In this embodiment of the application, in step S5, the pressure drop rate is judged in real time during the pressure holding period. If the pressure drop exceeds the preset rate threshold per unit time, an audible and visual alarm is triggered in advance and the test is terminated.

[0053] In this embodiment, specifically, the control unit 160 collects pressure values ​​at regular intervals, such as every second, and calculates the pressure drop within that minute every 60 seconds. If the pressure drop exceeds a preset rate threshold, it indicates a significant leak in the tested pipeline, and continuing to maintain pressure would only waste time. At this point, the control unit 160 immediately triggers an audible and visual alarm, emitting a buzzer and flashing a red light, and simultaneously terminates the pressure holding test, without waiting for the remaining pressure holding time.

[0054] In the above, the preset rate threshold is set to 0.02 bar / min.

[0055] In this embodiment of the application, in step S6, if the pressure drop value is ≤ the qualified pressure drop threshold P th If the test is passed, a green light will illuminate to indicate that the test is successful, and a test record form will be automatically generated. If the pressure drop value is greater than the acceptable pressure drop threshold P th If the test fails, the test is deemed unqualified, an audible and visual alarm is triggered, and the unqualified data is recorded. When the test is deemed unqualified, the device automatically records the pressure value and corresponding time at the moment of leakage, and automatically jumps to step S3 to re-perform the pressure holding test, and records the number of retests; if the test still fails after a preset number of retests, the test is stopped and an alarm is triggered.

[0056] In this embodiment, after the control unit 160 completes the comparison, it processes the following qualified and unqualified cases separately: Acceptable condition: If the pressure drop value is ≤ acceptable pressure drop threshold P th The control unit 160 determines that the test is qualified, illuminates the green indicator light installed on the operation panel, and automatically generates an electronic record sheet containing all test data, which can be printed as a paper report.

[0057] Unacceptable condition: If the pressure drop value is greater than the acceptable pressure drop threshold P th The control unit 160 determines that the test is unqualified, triggers an audible and visual alarm, and simultaneously records the pressure value and corresponding time at the moment when the pressure drop rate abnormally changes, as a basis for fault analysis. In addition, the control unit records the number of retries for the current test. If the current number of retries has not reached the preset maximum number of retries, it automatically jumps back to step S3 to repeat the pressure holding test; if the maximum number of retries has been reached, the test stops and a fault alarm is output, and automatic retries cease, awaiting manual intervention from the operator.

[0058] This automatic retry function requires no manual intervention, greatly improving operational efficiency, and is especially suitable for production line scenarios that require repeated inspections until a result is satisfactory. During multiple retry processes, all unsuccessful test data is saved for later analysis.

[0059] In this embodiment of the application, after step S7, a pressure relief step is also included: automatically controlling the electromagnetic shut-off valve 180 or manually operating the pressure relief valve to release the pressure in the system pipeline.

[0060] In this embodiment, after the test, before the operator disconnects the connecting hose, the compressed air in the tested vehicle's piping and the device's internal piping must be released to ensure operational safety. The control method provides two depressurization methods: Automatic pressure relief: After completing the last test and generating a record sheet, the control unit 160 automatically opens the electromagnetic shut-off valve 180 to release the compressed air in the pipeline to the external environment until the pressure value detected by the second pressure sensor 151 drops to close to 0 bar.

[0061] Manual pressure relief: Operators can also directly open the pressure relief channel and quickly release pressure by rotating the manual pressure relief valve handle on the control panel. Manual pressure relief is used in case of a malfunction or power failure in control unit 160.

[0062] After the pressure is released, the pressure gauge 152 reading will return to zero, and the operator can then safely disconnect the connecting hose.

[0063] In this embodiment of the application, the self-test procedure in step S1 specifically includes: performing a sealing test on the piping system of the device body to ensure that the device itself has no leaks before entering the standby state.

[0064] In this embodiment, the detailed self-test procedure is as follows: First, the control unit 160 closes all output interfaces connected to the vehicle under test, forming a closed loop within the device's internal piping. Then, the control unit 160 starts the air pump, pressurizing the internal piping to a set pressure via the pressure boosting valve 131, closes the electromagnetic shut-off valve 180, and begins timing and monitoring the second pressure sensor 151 installed at the outlet of the air storage unit 140. After maintaining the pressure for 30 minutes, the control unit 160 calculates the pressure drop. If the pressure drop does not exceed 0.1 bar, the device's piping is deemed to be well-sealed, the self-test is considered successful, and the control unit 160 displays "self-test passed" on the touchscreen, the device enters standby mode, and the vehicle under test can be connected for testing. If the pressure drop exceeds 0.1 bar, the device is deemed to have a leak, the control unit 160 displays "self-test failed" and the estimated leak location on the touchscreen, prohibits further testing, and prompts maintenance personnel to repair the device. This self-test function ensures the reliability of the device before each use, avoiding misjudgments of the airtightness of the vehicle under test due to equipment leaks.

[0065] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A device for detecting the airtightness of pipes in subway cars, characterized in that, include: Gas supply pipe (110), the input end of which is connected to a gas source; A first pressure sensor (120) is disposed on the gas supply pipe (110), and the first pressure sensor (120) detects the gas pressure of the gas supply pipe (110); A pressure regulating device (130) is provided on the gas transmission pipe (110), and the pressure regulating device (130) regulates the gas pressure of the gas transmission pipe (110); A gas storage unit (140) is installed on the gas transmission pipe (110), and the gas inlet of the gas storage unit (140) is connected to the gas outlet of the pressure regulating device (130). The detection unit (150) includes a second pressure sensor (151) and a pressure gauge (152). The detection end of the second pressure sensor (151) is connected to the gas outlet pipeline of the gas storage unit (140), and the pressure gauge (152) is connected in parallel to the gas outlet pipeline. An output interface is provided at one end of the detection unit (150). The control unit (160) is electrically connected to the first pressure sensor (120), the pressure regulating device (130), and the detection unit (150).

2. The subway car pipeline airtightness testing device according to claim 1, characterized in that, The pressure regulating device (130) includes: A pressure boosting valve (131) is provided on the gas transmission pipe (110); Overflow valve (132); the input end is connected to the output end of the booster valve (131) through the gas supply pipe (110), and the output end of the overflow valve (132) is connected to the atmosphere or return air pipeline, which is used to automatically open and release pressure when the system pressure exceeds the set value.

3. The subway car pipeline airtightness testing device according to claim 2, characterized in that, An air filter (170), an electromagnetic shut-off valve (180), and a pressure booster valve (131) are sequentially arranged on the gas pipeline (110) along the airflow direction.

4. The subway car pipeline airtightness testing device according to claim 1, characterized in that, It also includes a mobile cart (100), on which the gas supply pipe (110), the first pressure sensor (120), the pressure regulating device (130), the gas storage unit (140), the detection unit (150) and the control unit (160) are all installed; The mobile trolley (100) has a four-wheel structure, and the front wheels of the mobile trolley (100) are equipped with a locking mechanism; The mobile vehicle (100) has a closed outer shell, which is equipped with a protective net or sealing structure to prevent small animals from entering.

5. A control method, executed by the subway car pipe airtightness detection device according to claim 3, characterized in that, Includes the following steps: Step S1: Start the self-test program to check the sealing of the device's own pipelines. If the self-test is qualified, it will enter the standby state. Step S2: Receive the test parameters input by the user, including the target holding pressure value P0, the holding time T0, and the qualified pressure drop threshold P. th ; Step S3: Control the opening of the electromagnetic shut-off valve (180) and the pressure boosting valve (131) so that the workshop air source is purified and pressurized before being supplied to the pipeline of the test vehicle. At the same time, the pressure value P fed back by the first pressure sensor (120) is collected in real time. Step S4: When P reaches P0±ΔP, the electromagnetic shut-off valve (180) is automatically closed to stop inflation, where ΔP is the allowable deviation; Step S5: Enter the pressure holding stage, continuously monitor the pressure value P and record the time. When the pressure holding time reaches T0, calculate the difference between the pressure value at the beginning of the pressure holding and the pressure value at the end of the pressure holding. This difference is the pressure drop value. Step S6: Compare the pressure drop value with the acceptable pressure drop threshold P th Comparison: Step S7: Automatically store the experimental process data and generate an electronic record sheet.

6. The control method according to claim 5, characterized in that, Step S2 also includes an identity verification sub-step: before inputting test parameters, the operator is identified, and the test parameters can only be received after successful verification; and the operator's electronic signature is associated with the generated test record table.

7. The control method according to claim 5, characterized in that, In step S5, the pressure drop rate is judged in real time during the pressure holding period. If the pressure drop exceeds the preset rate threshold per unit time, an audible and visual alarm is triggered in advance and the test is terminated.

8. The control method according to claim 5, characterized in that, In step S6, if the pressure drop value is ≤ qualified pressure drop threshold P th If the test is passed, a green light will illuminate to indicate that the test is successful, and a test record form will be automatically generated. If the pressure drop value is greater than the acceptable pressure drop threshold P th If the test fails, the test is deemed unqualified, an audible and visual alarm is triggered, and the unqualified data is recorded. When the test is deemed unqualified, the device automatically records the pressure value and corresponding time at the moment of leakage, and automatically jumps to step S3 to re-perform the pressure holding test, and records the number of retests; if the test still fails after a preset number of retests, the test is stopped and an alarm is triggered.

9. The control method according to claim 5, characterized in that, The process after step S7 also includes a pressure relief step: automatically controlling the solenoid shut-off valve (180) or manually operating the pressure relief valve to release the pressure in the system pipeline.

10. The control method according to claim 5, characterized in that, The self-test procedure in step S1 specifically includes: performing a sealing test on the piping system of the device body to ensure that the device itself has no leaks before entering the standby state.

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