High purity gas pipeline helium leak detection methods mainly include the following:
i. Inward Leak Detection Method (Helium Injection Method/Helium Injection Method)
operation method: vacuum inside the high-purity gas pipeline, and then spray helium to the pipeline from the outside.
Detection principle: by detecting whether the inside of the pipeline inhales helium to determine whether there is a leak.
Leakage rate requirements: the measured leakage rate shall not be greater than 1 × 10 ^-9 mbar · l/s.
II. Valve seat leak detection method
how to operate: Fill with helium upstream of the valve while pulling a vacuum downstream.
Detection principle: by detecting whether the downstream detection of helium to determine whether the valve seat leakage.
Leakage rate requirements: the measured leakage rate shall not be greater than 1 × 10 ^-6 mbar · l/s.
Three, outward leak detection method (suction gun method)
operation method: Fill the high-purity gas pipeline with helium or helium-nitrogen mixture, and then use an external suction gun to check for possible leaks.
Detection principle: by detecting whether the external suction gun sucked helium to determine whether there is a leak.
Leakage rate requirements: the measured leakage rate shall not be greater than 1 × 10 ^-6 mbar · l/s.