Leak detection of high-pressure solenoid valves of pvd coating machines is a very challenging task for high-pressure solenoid valve products used in natural gas gas stations or industrial gas pipeline transmission such as hydrogen. In order to ensure that hydrogen does not overflow the valve, this requires a very low leak rate to test this product, the leak rate should not be greater than 1×10-6 mbar l/sec. After comparative testing: this leak rate range is much lower than the leak rate at which we can see bubbling air escaped from the water (the maximum value of air bubbles visible to the naked eye in water is approximately equal to 10-3 mbar l/sec).

       Technical requirements for the road to custom leak detection system for pvd coating machine:
       1. The pressure of the valve is between 0.5 and 360 bar. All tests are required to be completed in a fully automated environment.
       2. A test gas recovery system for continuous measurement and free choice of test gas concentration. Technical requirements background: If a valve is filled with helium, the subsequent continuous filling of helium will decrease. Approximately 180 liters of helium will be released in a single-cycle test system with a pressure of 360 bar and an internal valve capacity of 0.5 liters. Due to the complexity of the gas production process and cost issues, helium is an expensive test gas. Test gas recovery system can bring more benefits from both economic and ecological aspects. And the recycling rate can reach more than 95%.
       3. In order to ensure that the calibrated test pressure is above 360 bar and avoid any possible pressure peaks, a high-pressure comparison system with a pressure up to 500 bar must be developed. The test gas needs to be stored in a buffer container with a special device to gradually release downward gas.
       4. In addition, the customized leak detection system of the pvd coating machine requires an additional functional valve test system: when the nitrogen pressure is above 100 bar, the pressure can flow from the valve to the atmosphere. In this process, the flow rate will reach 2.5 times the speed of sound, and the result will be a lot of noise, which requires a special mute device.