Rotary valve top seal assembly
AssigneeWalworth Company
InventorPieter F. Hoos
Life of this patent
Estimating the term…
Abstract
In a rotary valve, such as a plug valve having a body cavity opening from the top, a top seal assembly includes a membrane of polytetrafluoroethelene or the like which extends over the cavity opening with its outer edges clamped between the valve body and a top closure. A groove around the opening accommodates cold flow of material from between the clamped surfaces beyond it. A circular opening in the membrane embraces and seals around the valve stem and an underturned lip around the opening engages against a generally horizontal sealing surface around the plug stem to be urged into sealing engagement by a load ring, providing a second, pressure augmented annular seal.
Claims7
In a rotary valve comprising:
- a valve body having flow passages therethrough;
- a cavity in said valve body opening from the top thereof;
- a top closure bolted to said valve body over said cavity;
- a valve closure member;
- a stem on said closure member rotatable in said top closures;
- and,
- a seal surface on said closure member around said stem and extending generally radially thereof;
- a top seal assembly for said valve comprising;
- a membrane of semi-rigid, distortable material extending over said cavity opening with outer portions thereof clamped between said valve body and said top closure;
- a generally circular opening in said membrane snugly receiving and sealing around said stem;
- an under-turned lip around said opening with an annular edge thereof engaging said seal surface;
- a loading ring around said stem mounted for movement therealong, the under surface of said loading ring being relieved around the inner diameter thereof overlying said lip;
- and
- means for forcing said loading ring downward to bias said lip against said seal surfaces.
Dependencies are inferred from the claim text.