In troubleshooting vacuum integrated valves, quickly locating leaks requires combining system characteristics with testing techniques, employing a step-by-step troubleshooting approach to achieve precise identification. As a core component of a vacuum system, leaks in vacuum integrated valves can be caused by aging seals, welding defects, mechanical damage, or improper installation. Leaks not only reduce vacuum levels but can also lead to system instability and even equipment damage; therefore, a systematic approach is necessary to quickly pinpoint the leak.
Initial troubleshooting should focus on the appearance and basic condition of the vacuum integrated valve. Inspect the valve body surface for cracks, deformation, or corrosion; these mechanical damages can directly cause leaks. Simultaneously, observe the sealing conditions of connections such as flanges and threaded interfaces, confirming whether gaskets are aged, deformed, or misaligned. For example, rubber seals may harden and crack after prolonged use, and metal gaskets may develop gaps due to insufficient clamping force; these require initial assessment through visual inspection or touch.
If no external abnormalities are found, further testing of the sealing performance is necessary. For the dynamic sealing structure of a vacuum integrated valve, a bubble leak detection method can be used: immerse the valve in soapy water or a special leak detection solution, and slowly operate the valve (e.g., open/close), observing whether bubbles are generated on the sealing surface. If bubbles are continuously emitted, it indicates a leak at that location. This method is suitable for preliminary screening under low-pressure conditions, is simple to operate, and low in cost. However, it is important to ensure that the leak detection solution evenly covers the sealing surface to avoid missing critical areas.
For high-pressure or high-vacuum conditions, more precise detection methods are required. A helium mass spectrometer leak detector is the core tool for locating tiny leaks. Its principle is to fill the vacuum system with helium and detect changes in the external helium concentration using a mass spectrometer to pinpoint the leak. In practice, the vacuum integrated valve needs to be isolated from the system, and helium should be filled into the valve body (or blown externally) while simultaneously scanning the valve body surface with a leak detector probe. When the probe detects a helium signal, the leak location can be determined. This method has extremely high sensitivity and can detect leaks at the micron level, but requires specialized equipment and is suitable for scenarios with stringent vacuum requirements. If the leak is located inside the valve body or in a difficult-to-detect area, the pressure decay method can be used to assist in diagnosis. Connect the vacuum integrated valve to a vacuum pump, evacuate to the target vacuum level, and then close the valve. Monitor the system pressure change over time. If the pressure continues to rise, it indicates a leak. By comparing the pressure rise rate over different time periods, the size of the leak can be preliminarily determined. Combining this with a segmented isolation method (such as closing valves or pipelines segment by segment) can further narrow down the leak location, ultimately pinpointing the specific component.
For the welded areas of the vacuum integrated valve, the weld quality needs to be carefully inspected. Welding defects (such as porosity, cracks, and lack of fusion) are common causes of leaks, especially under high pressure or high temperature conditions. A fluorescent penetrant detection method can be used: a fluorescent penetrant is sprayed onto the weld surface, penetrating into tiny cracks; after removing excess penetrant, a developer is applied. The penetrant in the cracks fluoresces under ultraviolet light, thus visually indicating the leak location. This method is suitable for detecting surface cracks in metal valve bodies, is simple to operate, and provides reliable results.
If the above methods fail to locate the leak, internal structural issues must be considered. For example, the valve core and seat of a vacuum integrated valve may fail to seal due to wear or foreign object obstruction. In this case, the valve needs to be disassembled to check the smoothness, scratches, or corrosion of the mating surfaces of internal parts, and to clean impurities from the valve cavity. For repairable parts (such as slightly worn valve seats), sealing can be restored by grinding or polishing; for severely damaged parts, replacement is necessary.
Quickly locating leaks in vacuum integrated valves requires a comprehensive approach, utilizing visual inspection, bubble detection, helium mass spectrometry, pressure decay analysis, fluorescence penetrant testing, and internal structural analysis. A step-by-step, layered approach to troubleshooting can efficiently pinpoint the leak, providing a basis for subsequent repairs. In practice, the appropriate method should be selected based on the operating conditions of the vacuum system, equipment specifications, and the severity of the leak to ensure the accuracy and reliability of the diagnostic results.
