API Butterfly Valve Sealing Form

Structure Classification

Centerline sealing

The center axis of the butterfly plate and the vertical centerline of the valve body, rubber and other non-metallic pressure valve body or seat, butterfly plate outer ring and soft sealing valve seat extrusion to produce elastic deformation, so that the valve sealing.

Single eccentric sealing: single eccentric distance set so that the butterfly plate and seat sealing surface is a complete circle, opening and closing the sealing surface between mechanical wear and extrusion to reduce, sealing performance, applicable working pressure and service life than the center line type has improved.

Double eccentric sealing

When closing, the sealing surface of the outer circle of the butterfly plate squeezes the valve seat, which has a larger and better sealing pressure. The sealing performance of this structure is better than the single eccentric type, the use of pressure is also higher, longer service life.

Three eccentric sealing

When opening, the butterfly plate immediately leaves the seat sealing surface, when closing, only in the closing moment the butterfly plate sealing surface will contact and press the seat sealing surface, the sealing pressure between the two sealing surfaces is determined by the eccentric distance and the size of the torque of the valve stem.