Triple Eccentric Butterfly Valve
Triple eccentric means:-
1)First eccentric is the offset between the shaft centre line and the disc trunnion centre line.
2)Second eccentric is the offset between the body centre line and the disc centre line.
3)The third and the most important is the eccentric in the sealing(multiple) itself such that if you draw a imaginary contour line between the sealing shape vs the body centre,It becomes a cone with one side flat on surface.(I hope my words are clear enough to make you understand).
The reason for this shape is because it gives better sealing ability for the valve.eg:- Fire safe valves are triple eccentric valves which are also called pyrogenic butterfly valves.The sealings are multiple in nos. and together they form a pyrogenic shape therefore this sealing is also called pyrogenic sealing.
