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An ANSI Leakage Class V control valve having consistent shut off characteristics with a reduced actuator force required to open and close the valve is provided. The trim arrangement of the control valve includes a valve cage having a multi-contoured inner surface. The multi-contoured inner surface c

An ANSI Leakage Class V control valve having consistent shut off characteristics with a reduced actuator force required to open and close the valve is provided. The trim arrangement of the control valve includes a valve cage having a multi-contoured inner surface. The multi-contoured inner surface can include a plurality of surfaces. The multi-contoured surface can include first, second, and third perimeter surfaces, and a first transition surface disposed between and coupling the first and second perimeter surfaces, and a second transition surface disposed between and coupling the second and third perimeter surfaces. The valve also includes a valve plug disposed at one end of a valve stem. The valve plug controls the fluid flow through the valve. The valve plug includes an opening through the plug for equalizing pressure across the valve plug. An annular channel is formed within a wall of the valve plug and is sized to accommodate a sealing ring. The sealing ring engages the second perimeter surface to form a fluid seal that substantially hinders fluid leakage through the valve.

대표청구항 ▼

1. A valve, comprising:a valve body having an inlet port and an outlet port; a valve seat disposed within the valve body defining an opening fluidly communicating between the inlet port and the outlet port; a valve stem extending through the valve body and movable therethrough along an axis; a valve

1. A valve, comprising:a valve body having an inlet port and an outlet port; a valve seat disposed within the valve body defining an opening fluidly communicating between the inlet port and the outlet port; a valve stem extending through the valve body and movable therethrough along an axis; a valve plug coupled to one end of the valve stem, the valve plug having a closed position, in which the valve plug engages the valve seat to form a primary seal, wherein the valve plug is movable away from the closed position to control a fluid flow through the valve seat opening, the valve plug including a conduit adapted to equalize pressure across the valve plug and an annular channel; a sealing ring disposed within the annular channel of the valve plug; and a valve cage disposed within the valve body and having an internal surface sized to receive the valve plug, wherein a gap between the valve cage and the valve plug defines a secondary leak path, the valve cage internal surface including a multi-contoured inner perimeter surface having at least a first perimeter surface and a second perimeter surface, with a first transition surface disposed between the first perimeter surface and second perimeter surface, the second perimeter surface being formed as a generally cylindrical wall substantially concentric with the valve stem axis and being sufficiently proximate the valve plug to sealingly engage the sealing ring, thereby to form a secondary seal restricting fluid leakage through the secondary leak path, and the first perimeter surface being disposed farther away from the valve plug than the second perimeter surface. 2. The valve of claim in which the multi-contoured inner perimeter surface of the valve cage further includes a third perimeter surface and a second transition surface disposed between the second perimeter surface and the third perimeter surface, wherein the third perimeter surface is substantially concentric with the valve stem axis and is disposed closer to the valve plug.3. The valve of claim 1, in which the first perimeter surface is substantially concentric with the valve stem axis.4. The valve of claim 1, in which the sealing ring comprises a C-ring having an opening.5. The valve of claim 4, in which the C-ring is oriented so that the opening receives fluid flowing through the secondary leak path, so that the fluid fills the opening and pushes the C-ring against the second perimeter surface, thereby to improve the secondary seal.6. The valve of claim 1, in which the sealing ring comprises a material suitable for operation at temperatures of at least about 450° F.7. The valve of claim 6, in which the material comprises a metal.8. The valve of claim 1, further comprising a piston ring disposed between the valve cage and the valve plug for forming a fluid seal with the valve cage.9. The valve of claim 1, in which the sealing ring is adapted to slide along the second perimeter surface during use.10. The valve of claim 1, in which the first transition surface has a generally frustoconical shape formed at an angle of about 7.5 degrees with respect to the valve stem axis.11. A valve, comprising:a valve body having an inlet port and an outlet port; a valve seat disposed within the valve body defining an opening fluidly communicating between the inlet port and the outlet port; a valve stem extending through the valve body and movable therethrough along an axis; a valve plug coupled to one end of the valve stem, the valve plug having a closed position, in which the valve plug engages the valve seat to form a primary seal, wherein the valve plug is movable away from the closed position to control a fluid flow through the valve seat opening, the valve plug including a conduit adapted to equalize pressure across the valve plug; and a valve cage disposed within the valve body and having an internal surface sized to receive the valve plug, wherein a gap between the valve cage and the valve plug defines a secondary leak path; wherein one of the valve cage and valve plug is a secondary seal bearing component that includes a channel sized to receive a sealing ring; and wherein the other of the valve cage and valve plug is a secondary seal mating component that includes a multi-contoured inner perimeter surface, the multi-contoured inner perimeter surface having at least a first perimeter surface and a second perimeter surface, with a first transition surface disposed between the first perimeter surface and second perimeter surface, the second perimeter surface being formed as a generally cylindrical wall substantially concentric with the valve stem axis and being sufficiently proximate the seal bearing component to sealingly engage the sealing ring, thereby to form a secondary seal restricting fluid leakage through the secondary leak path, and the first perimeter surface being disposed farther away from the seal bearing component than the second perimeter surface. 12. The valve of claim 11, in which the secondary seal bearing component comprises the plug and the secondary seal mating component comprises the cage.13. The valve of claim 11, in which the multi-contoured inner perimeter surface of the valve cage further includes a third perimeter surface and a second transition surface disposed between the second perimeter surface and the third perimeter surface, wherein the third perimeter surface is substantially concentric with the valve stem axis and is disposed closer to the valve plug.14. The valve of claim 11, in which the first perimeter surface is substantially concentric with the valve stem axis.15. The valve of claim 11, in which the sealing ring comprises a C-ring having an opening.16. The valve of claim 11, in which the C-ring is oriented so that the opening receives fluid flowing through the secondary leak path, so that the fluid fills the opening and pushes the C-ring against the second perimeter surface, thereby to improve the secondary seal.17. The valve of claim 11, in which the sealing ring comprises a material suitable for operation at temperatures of at least about 450° F.18. The valve of claim 17, in which the material comprises a metal.19. The valve of claim 11, further comprising a piston ring disposed between the valve cage and the valve plug for forming a fluid seal with the valve cage.20. The valve of claim 11, in which the sealing ring is adapted to slide along the second perimeter surface during use.21. The valve of claim 11, in which the first transition has a generally frustoconical shape formed at an angle of about 7.5 degrees with respect to the valve stem axis.22. A high temperature valve comprising:a valve body having an inlet port and an outlet port; a valve seat disposed within the valve body defining an opening fluidly communicating between the inlet port and the outlet port; a valve stem extending through the valve body and movable therethrough along an axis; a valve plug coupled to one end of the valve stem, the valve plug having a closed position, in which the valve plug engages the valve seat to form a primary seal, wherein the valve plug is movable away from the closed position to control a fluid flow through the valve seat opening, the valve plug including a conduit adapted to equalize pressure across the valve plug and an annular channel; a sealing ring disposed within the annular channel of the valve plug; and a valve cage disposed within the valve body and having an internal surface sized to receive the valve plug, in which the valve cage internal surface includes a multi-contoured inner perimeter surface having at least a first perimeter surface and a second perimeter surface, wherein the second perimeter surface sealingly engage the sealing ring over a range of sealing positions and the first perimeter surface is disposed farther away from the valve plug than the second perimeter surface wherein a gap between the valve cage and the valve plug defines a secondary leak path, the valve cage internal surface sealingly engaging the sealing ring to form a secondary seal restricting fluid leakage through the secondary leak path over a range of plug positions, thereby to accommodate differences in thermal expansion between the valve plug and valve cage. 23. The valve of claim 22, in which the sealing ring comprises a material suitable for operation at temperatures of at least about 450° F.24. The valve of claim 22, in which the valve cage internal surface includes a multi-contoured inner perimeter surface having at least a first perimeter surface and a second perimeter surface, wherein the second perimeter surface sealingly engages the sealing ring over a range of plug positions and the first perimeter surface is disposed farther away from the valve plug than the second perimeter surface.25. The valve of claim 24, in which the second perimeter surface is formed as a generally cylindrical wall substantially concentric with the valve stem axis.26. The valve of claim 22, further comprising a first transition surface disposed between the first perimeter surface and second perimeter surface.27. The valve of claim 22, in which the sealing ring comprises a C-ring having an opening.28. The valve of claim 27, in which the C-ring is oriented so that the opening receives fluid flowing through the secondary leak path, so that the fluid fills the opening and pushes the C-ring against the second perimeter surface, thereby to improve the secondary seal.29. The valve of claim 22, which the sealing ring is adapted to slide along the second perimeter surface during use.30. The valve of claim 22, in which the first transition surface has a generally frustoconical shape fanned at an angle of about 7.5 degrees with respect to the valve stem axis.31. The valve of claim 22, in which the secondary seal allows a maximum fluid leakage substantially meeting ANSI Class V standards.