GB/T 32218-2015Vacuum technology—Test methods for leak rates of vacuum system (English PDF)

3.1 Effective minimum leak rate

Minimum leak was seized after connecting member and the leak detection system, leak detector and leak detection system under specific operating conditions, can leak detection

Leak rate.

Note. Units Pa cubic meters per second (Pa · m3/s).

3.2 Cumulative leak

After the pieces were seized evacuated and shut down the cumulative valve exhaust system isolation. When the subject member externally applied certain concentration of helium, if the subject member

The leakage hole, within the prescribed cumulative time from being leaked leak detection member helium will accumulate in the subject member that is Helium member within minutes

Pressure increases with the accumulation time. Open the valve when the cumulative cumulative time expires, use helium leak detectors detect the partial pressure of helium within the subject member, from

Calculated method is one kind of leak detection member total leak rate.

NOTE. It is a method used to detect small leaks of helium mass spectrometer leak detection methods.

3.3 Helium concentration

In the mixed gas, helium gas mixture and pressure points ratio of the total pressure.

4.1 helium mass spectrometry vacuum system leak rate testing principle

Gun or helium leak helium hood is shown through the drain hole into the subject member, and introduced into the leak detector, leak detector causes a change in the output instruction, […]