Abstract: The special valves in S Zorb unit have high switching frequency, special transmission medium and great change in working temperature and pressure, so imported valves are mostly used. However, faults such as internal leakage, jamming and over long switching time are inevitable during the long-term operation of valves. This paper analyzes the reasons for the faults of three special valves in the S Zorb unit of a company. Based on the similarity of the faults and referring to the particularity of the faults of valves from other manufacturers, some optimization measures and suggestions are put forward, which can effectively ensure the safe balance and long-term operation of the equipment.

Key words: sequencing valve, back-flushing valve, slide valve, fault, countermeasure