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Characteristics of O-rings in dynamic sealing conditions

Update:2018-12-22

DSH Seal share with you more about the basics of seals in low-pressure conditions (working environment or occasion).

Taking the safety valve seal as an example, the safety valve seal is a kind of valve used for the safety protection of the system's working pressure automatic opening and closing. According to the principle of action, it can be a direct acting safety valve seal and a non-direct acting safety valve seal. 

The large class, spring-loaded safety valve seals (Fig. 1) and pilot-operated safety valve seals (Fig. 1) are representative of these two types of safety valve seals. Taking these two common safety valve seals as an example, let us look at the main application (working environment) of the rubber O-ring.

Taking the pilot safety valve seal as an example (Fig. 2), the O-ring structure consisting of the main valve and the pilot valve controls the opening and closing of the main valve by the pilot valve sensing system pressure. The internal structure of the pilot valve is compact, the flow path is narrow, the space position is limited, the relative movement seals many parts, and the sealing part is tight. 

The piston seal structure between the main valve disc and the sealing guide sleeve not only leaks the medium in the chamber formed by the valve flap and the sealing guide sleeve, but also keeps the valve flap moving well when the safety valve sealing ring is opened. Sealing characteristics, the dynamic seal in the shaft does not use rubber O-rings in most cases.