The detachable surface parts in the valve are used to support the fully closed position of the valve core and form the sealing pair. Generally, the seat diameter is the maximum flow diameter of the valve. For example, the seat material of butterfly valve is very wide, all kinds of rubber, plastic and metal materials can be used as seat material, such as: EPDM, NBR, NR, PTFE, PEEK, PFA, SS315, STELLITE and so on.
