Elliptical sealing surface for butterfly valve

Abstract

A reduced component wear valve is comprised of a valve body having a passage therethrough and a disc attached to a rotatable shaft. The disc is utilized with a seal forming a gap between the disc and the seal proximate to the rotational axis 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.

1 - 49 . (canceled) 
   
   
       50 . A valve having reduced seal wear and reduced friction comprising:
 a valve body having an inlet and an outlet forming a passage in the valve body, and a valve body side recess;   a valve stem extending into the valve body;   a disc rotatable by the valve stem to open and close the passage, the disc having a perimeter;   a valve seal having an elliptical first shape with a major axis greater than a minor axis, the valve seal deforming through contact with the disc as the disc rotates to a closed position to a second shape different from the first shape in which the valve seal substantially contacts the disc perimeter, thereby to substantially close the passage, wherein the valve seal is formed of a resilient material that substantially returns to the first shape when the disc subsequently moves back toward an open position, wherein the valve seal includes a peripheral portion; and   a seal cartridge, including a deformable annular seal element having a generally U-shaped cross-section about its periphery, said valve seal being sandwiched between a pair of annular seal support and retainer members operatively received and retained within the valve body side recess.   
   
   
       51 . The valve of  claim 50 , wherein the deformable annular seal element is metal. 
   
   
       52 . The valve of  claim 50 , wherein the deformable annular seal element has a rounded, radially inner annular portion that projects inwardly from each of the pair of seal support and retainer members, the rounded, radially inner annular portion providing operative sealing engagement by the disc perimeter.