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US 4,385,747 AGranted
Self-relieving seat and ball valve incorporating the same
AssigneeWorcester Controls Corporation
InventorsPaul Renaud, Jr., Kenneth Paradis
Life of this patent
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AssigneeWorcester Controls Corporation
InventorsPaul Renaud, Jr., Kenneth Paradis
Estimating the term…
An annular seat for use in a ball valve has two groups of pressure relief passageways each of which extends completely through the seat between its front and rear faces. The relief passageways in one group are located adjacent the outer periphery of the seat. The passageways in the second group are located radially inward of the passageways in the first group, and extend between the rear face of the seat and a curved sealing surface on the front face of the seat. A pair of such seats are disposed in a ball valve housing adjacent opposite sides of a rotatable ball. The interior seat support surfaces in the housing have machined recesses adjacent the central axial fluid passageway through each seat, to facilitate lip flexure of the seats. The overall arrangement provides a bidirectional valve which seals on the downstream side only of the valve, and which relieves excessive cavity pressure in the valve past the upstream seat. The seats may be provided with chamfered outer rear corners to facilitate the pressure relief operation at the upstream side of the valve under conditions of extremely rapid cavity pressure generation.
A seat ring for a ball valve adapted to seal against a ball in the valve, said seat ring comprising an annular body of elastomeric material having a fluid passageway centrally located therein and extending axially therethrough, said annular body having a rear face, a front face spaced from said rear face and extending radially outward of said fluid passageway, and an outer peripheral wall extending between the radial outermost portions of said front and rear faces, said front face including a curved surface which extends radially outward from said fluid passageway and which terminates in cross section in a radial outward direction at a point that is disposed radially inward of said outer peripheral wall, at least one first pressure relief passageway extending completely through said annular body from the rear face thereof to the region of said front face between said outer peripheral wall and the radial outward termination of said curved surface, and at least one second pressure relief passageway extending completely through said annular body from the rear face of said body to a region of said curved surface located between said axial fluid passageway and the radial outward termination of said curved surface.
In a ball valve of the type comprising a housing having an interior cavity located between and communicating with a pair of fluid flow channels to define an axial flow passage extending through said housing, a ball located in said cavity, said ball having an axially directed bore extending therethrough, said ball being mounted for rotation about an axis of rotation transverse to said flow passage whereby its said bore may be selectively aligned with or disposed transverse to the axial flow passage in said housing to control the flow of fluid therethrough, and a pair of annular seat rings supported by said housing in surrounding relation to said axial flow passage adjacent the upstream and downstream sides of said cavity respectively for sealing engagement with said housing and ball, each said ring including at least one pressure relief passageway extending in an axial direction completely therethrough between the front and rear faces of the ring at a location in said seat ring located radially outward of the regions of sealing engagement of said ring to said ball and housing, the improvement wherein each of said seat rings includes at least one auxiliary pressure relief passageway extending completely therethrough between the front and rear faces of the ring, one end of said auxiliary pressure relief passageway being located at a region of the front face of said seat ring that is radially inward of the outermost extremity of the region of sealing engagement between the front face of said ring and said ball, the other end of said auxiliary pressure relief passageway being located at a region of the rear face of said seat ring that is radially outward of the region of sealing engagement between the rear face of said ring and said housing, said seat rings and their respective pressure relief passageways being so positioned and dimensioned relative to one another and to said housing and ball that, upon occurrence of excess cavity pressure in said houing, said excess pressure is relieved past the upstream one of said seat rings via a pressure relief path which extends in sequence from the cavity in a generally axial direction through the first-mentioned pressure relief passageway of said upstream seat ring to the rear face of said ring, thence from the rear face of said ring in a generally axial direction via said auxiliary pressure relief passageway to the front face of said upstream seat ring, and thence in a radially inward direction to the central opening of said annular upstream seat ring and to the upstream one of the fluid flow channels in said housing.
Dependencies are inferred from the claim text.