Valve with seat assembly

A valve comprising:

• a valve body having a closure member and a closure member chamber therein, said valve body defining upstream and downstream passages extending through said valve body and being in communication with said chamber to define a flow path through said valve body, said valve body defining pockets surrounding said upstream and downstream passages adjacent to said closure member chamber;
• a telescoping seat assembly in said pockets, said telescoping seat assembly comprising,
• an outer seat element for sealing within said pocket of said valve body, and
• an inner seat element moveable with respect to said outer seat element for sealing engagement with said closure member, said outer seat element and said inner seat element defining surfaces therebetween whereby pressure in at least one of said inlet or outlet passages acting on said surfaces during operation of said valve urges said outer seat element to move relatively away from said inner seat element to enhance respective sealing with said pocket and said closure member,
• a seal disposed in a groove in at least one of said outer seat element or said inner seat element, said groove comprising therein a tapering surface, said tapering surface defining a groove depth which varies with increasing radial distance away from said flow path.

A valve comprising:

• a valve body having a closure member and a closure member chamber therein, said valve body defining inlet and outlet passages extending through said valve body and being in communication with said chamber to define a flow path through said valve body, said valve body having a pocket surrounding said inlet and outlet passages adjacent to said closure member chamber;
• a telescoping seat assembly in said pockets, said telescoping seat assembly comprising,
• an outer seat element for sealing within said pocket of said valve body;
• and
• an inner seat element moveable with respect to said outer seat element for sealing engagement with said closure member, said outer seat element and said inner seat element defining a slot therebetween, a pair of oppositely oriented unidirectional seals mounted within said slot.

A method for a valve, said valve having a valve body with a passageway therethrough and a gate chamber therein, a pair of recesses along said passageway adjacent said gate chamber;

• said method comprising:
• providing telescoping seat assemblies with inner and outer seat components for each of said recesses to thereby form a flow path between said inner and outer seat components, said outer seat components and said inner seat components defining surfaces therebetween whereby pressure in at least an upstream portion of said passageway acting on said surfaces during operation of said valve urges a respective outer seat component to move relatively away from a respective inner seat component;
• forming a groove in at least one of said inner and outer seat components;
• providing a tapering groove wall within said groove which is angularly offset with respect to said passageway;
• and
• providing a seal ring which is moveable in said groove along said tapering groove wall.

A valve body having a closure member and a closure member chamber therein, inlet and outlet passages extending through said valve body and being in communication with said closure member chamber to define a flow path through said valve body, said valve body defining a pocket surrounding said inlet and outlet passages adjacent to said closure member chamber;

• a telescoping seat assembly in said pockets, said telescoping seat assembly comprising,
• an outer seat element for sealing within said pocket of said valve body;
• an inner seat element moveable with respect to said outer seat element for sealing engagement with said closure member, said outer seat element and said inner seat element defining surfaces therebetween whereby pressure in at least one of said inlet or outlet passageways acting thereon during operation urges said outer seat element relatively away from said inner seat element to enhance respective sealing with said pocket and said closure member;
• and
• a groove disposed in at least one of said inner seat element or said outer seat element, a seal moveable within said groove along a tapering surface defining said groove.