Ball valve structure having pressure actuated seats

Claim 2

A valve comprising a valve body having a valve chamber, upstream and downstream flow passages formed in said valve body and being in fluid communication with said valve chamber, a valve member disposed within the valve chamber and being movable between open and closed positions to control the flow of fluid through the valve, a seat recess formed in the valve body on the upstream side of the valve member, upstream and downstream seat assemblies movably disposed within said seat recesses, said upstream seat assembly having a circumferential face seal in sealing contact with the valve memBer about a sealing perimeter, a separate annular member loosely mounted in the upstream seat recess adjacent the valve body and spaced from said associated upstream seat assembly to form an annular back seal chamber between the seat assembly and the annular member, an annular seal in said back seal chamber between the annular member and the associated seating assembly, and movable within the back seal chamber between innermost and outermost positions in sealing contact with the valve body, said annular seal being out of contact with the valve body when moving between said innermost positions and said loosely mounted separate annular member permitting a leakage of fluid between the annular member and the valve body when said annular seal is between said innermost and outermost positions of the back seal chamber so that upon an increase in body pressure to an extent greater than the upstream fluid pressure the annular seal is moved out of contact with the valve body and a leakage of fluid is effected from the valve body behind the separate annular member to relieve the body fluid pressure.

Claim 3

A valve as set forth in claim 1 wherein said separate annular member is generally triangular in cross section and has a face thereof adjacent the associated seat assembly defining the back seal chamber and inclined with respect to the longitudinal axis of the flow passages through the valve.

Claim 4

A valve as set forth in claim 1 wherein said annular seal is an O-ring.

Claim 5

A valve as set forth in claim 1 wherein resilient spring means continuously urges each seat assembly toward the valve member.

Claim 6

A valve as set forth in claim 1 wherein said back seal chamber has a width extending in a generally transversely direction with respect to the longitudinal axis of the valve.

Claim 7

A valve comprising a valve body having a valve chamber, upstream and downstream flow passages formed in said valve body and being in fluid communication with said valve chamber, a valve member disposed within the valve chamber and being movable between open and closed positions to control the flow of fluid through the valve, seat recesses formed in the valve body on opposite sides of the valve member, a pair of seat assemblies having a circumferential face seal in sealing contact with the valve member about a sealing perimeter, a separate annular member loosely mounted in each seat recess and spaced rearwardly from the associated seat assembly to form an annular back seal chamber between the associated seat assembly and the separate annular member in generally longitudinal alignment with the face seal, each back seal chamber having a width extending in a generally transversely direction with respect to the longitudinal axis of the valve, an annular seal in each back seal chamber between the annular member and the associated seating assembly, each back seal chamber exposed to both flowline and body fluid pressures, the outer extent of each back seal chamber extending radially outwardly of the perimeter of sealing contact of the associated face seal and the inner extent of said back seal chamber extending radially inwardly of the perimeter of sealing contact of said associated face seal with each annular seal providing a fluid tight seal between said annular member and the associated seating assembly, each annular seal being positioned in the outer extent of the associated back seal chamber in sealing contact with the valve body when the adjacent flowline fluid pressure is greater than the body fluid pressure and being positioned in the inner extent of the associated back seal chamber in sealing contact with the valve body when the body fluid pressure is greater than the adjacent flowline fluid pressure, each annular seal being out of contact with the valve body when moving between said inner and outer extents of said back seal chamber, each loosely mounted separate annular member permitting a leakage of fluid between the annular member and valve body when the annular seal is between the inner and outEr extents of the associated back seal chamber so that upon an increase in body pressure to an extent greater than the adjacent flowline fluid pressure the associated annular seal is moved out of contact with the valve body and a leakage of fluid is effected from the valve body behind the associated annular member to relieve the body fluid pressure.

Claim 8

A valve comprising a valve body having a valve chamber, upstream and downstream flow passages formed in said valve body and being in fluid communication with said valve chamber, a valve member disposed within the valve chamber and being movable between open and closed positions to control the flow of fluid through the valve, seat recesses formed in the valve body on opposite sides of the valve member, a pair of seat assemblies having a circumferential face seal in sealing contact with the valve member about a sealing perimeter, a separate annular member loosely mounted in each seat recess and spaced rearwardly from the associated seat assembly to form an annular back seal chamber between the associated seat assembly and the separate annular member in generally longitudinal alignment with the face seal, each back seal chamber having a width extending in a generally transversely direction with respect to the longitudinal axis of the valve, an annular seal in each back seal chamber between the annular member and the associated seating assembly, each back seal chamber exposed to both flowline and body fluid pressures, the outer extent of each back seal chamber extending radially outwardly of the perimeter of sealing contact of the associated face seal and the inner extent of said back seal chamber extending radially inwardly of the perimeter of sealing contact of said associated face seal with each annular seal providing a fluid tight seal between said annular member and the associated seating assembly, each annular seal being positioned in the outer extent of the associated back seal chamber in sealing contact with the valve body when the adjacent flowline fluid pressure is greater than the body fluid pressure and being positioned in the inner extent of the associated back seal chamber in sealing contact with the valve body when the body fluid pressure is greater than the adjacent flowline fluid pressure, each annular seal being out of contact with the valve body when moving between said inner and outer extents of said back seal chamber, each loosely mounted separate annular member permitting a leakage of fluid between the annular member and valve body when the annular seal is between the inner and outEr extents of the associated back seal chamber so that upon an increase in body pressure to an extent greater than the adjacent flowline fluid pressure the associated annular seal is moved out of contact with the valve body and a leakage of fluid is effected from the valve body behind the associated annular member to relieve the body fluid pressure.

Claim 9

A valve as set forth in claim 6 wherein said valve member is a gate valve member.

Claim 10

A valve as set forth in claim 6 wherein said valve member is a spherical plug valve member.