Acf Industries, Incorporated

Joy Manufacturing Company

William L Whaley

Willard J Sitton

A valve seat structure adapted to be positioned within each annular seat pocket (37, 36) which is formed about the flow passage (12, 13) adjacent the valve chamber on both the upstream and downstream sides of the gate element of a gate valve. The valve seat structure comprises a metallic seat ring (40) which fits snugly within the seat pocket (36, 37) but has an axial dimension which exceeds the depth of the pocket. The seat ring is formed with an annular notch (49, 50) in the outer corner of the ring at its rear face (48) for accommodating a resilient O-ring (66) therein. In its front face (47) the seat ring is provided with an annular groove (51) coaxial with the ring axis and provided with serrated side walls (51a, 51b). A plurality of passages (55) are formed in the ring with equiangular spacing and extend from the face groove (51) to the corner notch (49, 50). The passages (55) are filled with an elastomer (60 ) which is molded therein to fill the passages and the groove in the front face of the seat ring and is also bonded to the seat ring by an elastomer adhesive. The inner diameter of the face groove is less than the inner diameter of the corner notch such that the upstream seat structure tends to be pressure energized towards the gate of the valve to enhance its sealing effectiveness. The elastomer insert (60) is formed with a rounded face (65) which projects beyond the front face (47) of the seat ring. The annular opening of the groove in the face of the seat ring is formed with bevelled edges (53a, 53b) to provide a widened mouth of the groove which accommodates the deformed and compressed face of the elastomer sealing element when the gate element (16) is disposed in sealing engagement therewith. The accommodation of the elastomer material when compressed against the gate element enhances its resistance to wear and abrasion to extend the life of the valve and the passages (55) filled with elastomer (60) increase the resistance of the elastomer sealing element to being pressure extruded from the seat ring and enhances its sealing capabilities by being pressure energized towards the cooperating sealing surfaces of the valve.

Valve seat structure

A seat assembly for an expanding gate valve comprising an outer loose fitting main ring (31) with a resilient face seal (41) for sealing against an expanding gate assembly which is mounted in a valve chamber (11) and an inner auxiliary ring (44) fitting loosely in a counterbore recess in the main ring (31) for sealing against the rear wall (35) of a seat pocket (26). An O-ring (61) between opposed surfaces (51, 52) of the rings (31, 44) continuously urges the rings apart and their orientation such that when the gate assembly is expanded in its open and closed positions, the front face (38) of the main ring (31) is flush against the adjacent sealing surface (25) of the gate assembly and the rear face (46) of the auxiliary ring (44) is flush against the rear wall (35) of the seat pocket (26). When the sealing surfaces (24, 25) of the gate assembly are not parallel or there is a misalignment between the gate assembly sealing surfaces and the adjacent valve seat structure, pressurized fluid from the flow passage (12) enters between the rings (44, 31) of the upstream seat assembly. If there is a leak in the downstream seal or the valve chamber is free of flowline pressure, fluid pressure in the flowline forces the rings (31, 44) of the upstream seal assembly into sealing engagement with the gate element (19) and seat pocket wall (35), respectively. In addition, the O-ring (61) is radially expanded and compressed by the fluid pressure to seal between the rings (31, 44). The annular resilient seal (41) in the face (38) of the outer ring (31) is spaced a radial distance from the flow passage (12) which is less than the radial distance of the O-ring (61) from the flow passage (12) and provides a fluid pressure differential area for urging the outer ring (31) to seal against the valve element (19). The seat assembly is intended for upstream sealing but may be used as a downstream seal assembly which seals when the valve is closed by flowline pressure inducing a check valve action of the gate assembly.

A gate valve structure having a pair of opposed spacer carriers (72,74) fitting within the valve chamber in abutting relation to each other and spacing the floating upstream and downstream seats (60, 62) from each other a predetermined minimum distance. Each carrier (72, 74) has an annular base (76) adjacent one of the flow passages and a pair of spacers or guides (78, 80) secured to the base and extending from the base (76) in a direction axially of the flow passage. The spacers (78, 80) on opposed carriers are in abutting relation to each other and form a smooth continuation. An expanding gate assembly (28) fits between the spacers and moves between open and closed positions relative to the flow passages.

Growing community of inventors

Houston, TX, United States of America

William L Whaley