Flanged triple eccentric butterfly valve

Triple eccentric butterfly valve structure introduction:  
There are three different eccentric structure in the Triple eccentric butterfly valve.Two offsets are at the center and the third offset is on the sealing surface creating a cone-like shape of the disk and the seat. Triple offset valves are used where a bubble-tight seal is required, the system is under high temperature and hard sealing with zero leakage is needed.

First eccentric is provided to the central axis of the sealing surface in which the disc rotates 360-degree around the middle axis to provide sealing by deforming the soft seal which results in full friction.

Second eccentric refers to the position of the shaft with respect to the centerline of the bore. At the time of operation, it produces a cam action to lift the seat away from the seal, results in friction during the first 10 degrees of opening and the last 10 degrees of closure.

The third eccentric is the geometry of the closing elements. Each sealing element is machined into a conical offset profile, which results in a right-angled cone. Throughout its working cycle, this guarantees friction-free stroking. Contact is only made with the 90° angle functioning as a mechanical stop at the final point of closure; this results in no over-travel of the disc seat.

When these three eccentric structure is provided together the valve offers a continuous sealing surface, shows minimal wear between sealing surfaces, and provides durable sealing throughout the valve’s life. In addition, sticking and binding of the disk is lowered and less operating torque is required as it has an optimized seating angle.