Maintenance of Vacuum System in Finnigan Mat 4515 GC/MS

This paper introduces the maintenance of vacuum system in ten years old Finnigan Mat 4515 GC/MS. A scrapped oil diffusion pump from Finnigan Mat 4021 GC/MS was repaired and used instead of the damaged one of the Finnigan Mat 4515 GC/MS.This measure saves much money in purchasing a new set of instrument and is a valid experience for making full use of large scale instruments in China.The repairment is described in detail.