Helium mass spectrometer leak detector for through valve leak detection
Valve leak detection requirements
The sealing performance of a valve is one of the main indexes to evaluate the quality of the valve. Therefore, it is necessary to improve the sealing performance when designing and producing the valve. At present, many domestic valve manufacturers use water detection method and air pressure method to detect the tightness of the valve, but only large leakage can be detected by using this method, Generally, the minimum leak detection rate is 1x10e-3 mbar L / s. however, with the continuous improvement of product quality requirements by customers, water detection method and air pressure method have been unable to meet the requirements. In order to ensure product competition, many manufacturers have introduced helium leak detector. For the commonly used leak detection methods, helium leak detection method is recognized as one of the most advanced and reliable methods.
Valve leak detection method
The helium mass spectrometer leak detector has two leak detection modes, vacuum mode and positive pressure mode. Different leak detection methods can be selected according to different requirements of customers. Most valves use the negative pressure mode of leak detector, i.e. vacuum mode. The minimum detectable leakage rate is 5x10-12 mbar L / s.
Valve leak detection operation
1. The staff connected the through valve to be tested with bellows and helium mass spectrometer leak detector.
2. Start the rotary vane vacuum pump, vacuum the through valve, and start the helium mass spectrometer leak detector, and display a leakage rate value. When the rotary vane vacuum pump reaches a certain vacuum degree (the maximum back pressure is 25 mbar, the highest in the industry), the leakage detection operation can be carried out.
3. The staff sprayed helium into the sealing part of the through valve and the place suspected of leakage, and observed whether the leakage rate value displayed on the leak detector changed.
4. If the leakage rate increases, it indicates that there is leakage at the helium injection place, and the quality of the inspected object is unqualified. If the leakage rate value can meet the requirements, the inspected object is qualified and the leakage detection is completed.