Triple Offset Butterfly Valve Design

1st Offset

The axis upon which the stem shaft rotates is pushed back behind the centerline of the sealing points. This provides positive sealing and increased sealing capacity.

2nd Offset

The axis upon which the stem shaft rotates is pushed down below the centerline of the pipe. This reduces friction between the seat and disc which in turn reduces running torque.

3rd Offset

The vertex of the seat and seal cone is moved sideways to approximately the wall of the pipe. This creates elliptical sealing surfaces which completely eliminates seat and seal friction and creates a zero-leakage seal in high pressure and temperature ranges. The uniform compression of the seat and seal make it inherently fire-safe.