Abstract: A two-stage seal, such as a ring seal for use in a pressurized process fluid line, has a dynamic sealing member and a static sealing member. The dynamic sealing member is arranged to continuously sealingly engage against a seal surface that slides along the dynamic sealing member. The static sealing member is arranged to sealingly engage against the seal surface in response to an increased process fluid pressure within the process fluid line to increase static seal pressure against the seal surface. The static sealing member is also arranged to release from the seal surface to minimize friction with the seal surface when the process fluid pressure drops and/or in response to movement of the seal surface. The two-stage seal may be used in arrangements requiring both dynamic sealing and static sealing, such as in some process control valves. A process control valve having the two-stage seal is disclosed.

Abstract: A valve assembly includes a valve body having a body recess and a bonnet including a bonnet recess having a bonnet mating surface. The valve assembly further includes a valve cage disposed within an interior of the valve body, the valve cage including a body portion extending along a longitudinal axis and a circumferential mating protrusion extending from an outer surface in a transverse direction, the mating protrusion including an upper mating surface and a lower mating surface. The upper mating surface is disposed within the bonnet recess to be aligned with the bonnet mating surface, and the lower mating surface is disposed within the body recess to be aligned with the body mating surface, wherein the upper and lower mating surface are not parallel. Accordingly, clamping forces acting on the mating protrusion include a longitudinal and tangential component, allowing for increased clamping forces without plastically deforming the mating protrusion.

Abstract: A two-stage seal, such as a ring seal for use in a pressurized process fluid line, has a dynamic sealing member and a static sealing member. The dynamic sealing member is arranged to continuously sealingly engage against a seal surface that slides along the dynamic sealing member. The static sealing member is arranged to sealingly engage against the seal surface in response to an increased process fluid pressure within the process fluid line to increase static seal pressure against the seal surface. The static sealing member is also arranged to release from the seal surface to minimize friction with the seal surface when the process fluid pressure drops and/or in response to movement of the seal surface. The two-stage seal may be used in arrangements requiring both dynamic sealing and static sealing, such as in some process control valves. A process control valve having the two-stage seal is disclosed.