Seal assembly

Claim 1

A valve for controlling fluid flow comprising: a. A valve body having a passage therethrough; b. A valve closure means pivotally positioned in said valve body; c. a stem adapted to rotate said valve closure means; and, d. a seal assembly including: (i) a recess on said valve body adjacent to said passage, the depth of the recess increasing substantially uniformly with increasing distance from the passage; (ii) a retainer overlying the recess in said valve body, said retainer having a recess, the depth of the recess increasing substantially uniformly with increasing distance from the passage, the retainer recess disposed in juxtaposition to the recess on said valve body to thereby form a chamber therebetween adapted to receive a seat ring; and, (iii) a seat ring located in the chamber said seat ring having a base extending into the valve body passage and a plurality of legs depending from said base compressingly disposed in the chamber, said base having a perforation being blocked by said valve closure means when said valve closure means is rotated closed, each of said legs having a convex surface thereon adjacent to each respective recess, whereby fluid passing between a recess and one of said legs forces the convex surface on the other leg into fluid-tight engagement with its respective recess and with said valve closure means when said stem rotates said valve closure means into the closed position, the fluid in the chamber passing through the performation into the passage in said valve body when the stem rotates the valve closure means into the open position.