ELLIPTICAL SEALING SURFACE FOR BUTTERFLY VALVE

摘要

A reduced component wear valve (10) is comprised of a valve body (12) having a passage therethrough and a disc (14) attached to a rotatable shaft (38). The disc is utilized with a seal (18) forming a gap between the disc and the seal proximate to the rotational axis (16) of the disc. When the disc is in the open position, the seal major axis is greater then the disc diameter and they do not touch. As the disc rotates to near closure, the disc perimeter engages the minor axis of the seal (which is smaller than the disc diameter), and the disc stretches the seal in the minor axis direction thus decreasing the major axis such that the gap is closed. The seal can be pre-formed in an elliptical shape or it can be formed into an elliptical shape by a retaining mechanism. The seal may be a single-piece or a multi-piece assembly press-fit into the valve body. Zero or light disc to seal contact during the majority of the valve disc rotation minimizes valve seal wear and rotational friction.