Abstract: This paper analyzed the different faults of various components of the ZQJ-291H helium mass spectrometer leak detector by means of the failure mode effect and hazard analysis method, and studied the influence on the working status of the system. It is intended to identify the weakness in the use of equipment and provides an effective basis for improving the reliability of this type of helium mass spectrometer leak detector in terms of design, manufacture and use. The results show that the main factors, which affect the reliability of the ZQJ-291H helium mass spectrometer leak detector are the degradation of the pump oil and the aging of the ion source. Therefore, it is recommended to increase the research efforts on the loss of ion source and thus improve the reliability of the leak detector.

Key words: helium mass spectrometer leak detector, FMECA, reliability analysis