A segmented shaft seal is provided for circumferentially sealing an outer surface of a rotating shaft unit. The shaft seal includes a plurality of seal ring segments disposed within a housing having a circumferential spring holding the ring segments together. The ring segments further have lift groo
A segmented shaft seal is provided for circumferentially sealing an outer surface of a rotating shaft unit. The shaft seal includes a plurality of seal ring segments disposed within a housing having a circumferential spring holding the ring segments together. The ring segments further have lift grooves defined on the circumferential inner surfaces thereof to generate a radially outwardly directed lift force acting against the inwardly directed spring force. The lift grooves have a tapered profile radially and/or circumferentially to facilitate formation of the outwardly directed lift force as well as molding of the ring segments.
대표청구항▼
The invention claimed is: 1. In a segmented seal assembly configured for mounting on an equipment body and a rotatable shaft for sealing an outer shaft surface of said rotatable shaft which is rotatable about a shaft axis extending in an axial direction, said seal assembly including an annular seal
The invention claimed is: 1. In a segmented seal assembly configured for mounting on an equipment body and a rotatable shaft for sealing an outer shaft surface of said rotatable shaft which is rotatable about a shaft axis extending in an axial direction, said seal assembly including an annular seal ring which extends circumferentially about a center ring axis extending in said axial direction so as to extend about said outer shaft surface to sealingly separate first and second fluid regions, said seal ring comprising a plurality of arcuate ring segments which are assembled within said seal assembly circumferentially adjacent to each other so as to define said seal ring, each said ring segment having opposite first and second end faces, which extend radially outwardly in a radial direction and respectively face axially toward said first and second fluid regions, and having inner and outer segment surfaces, which extend axially in said axial direction between said first and second end faces and respectively face radially inwardly and outwardly relative to said ring axis so as to be radially spaced apart, wherein said inner and outer segment surfaces of said circumferentially adjacent ring segments extend circumferentially and respectively define an inner diameter and an outer diameter of said seal ring, said seal assembly including a biasing arrangement acting on said outer ring diameter to generate a respective biasing force on said ring segments which acts radially inwardly such that said inner diameter is adapted to sealingly cooperate with said outer shaft surface, comprising the improvement wherein said inner segment surfaces further include hydrodynamic lift means for receiving fluid from said first fluid region and generating a hydrodynamic fluid force during shaft rotation which biases said ring segments radially outwardly against said biasing force, said lift means comprising a plurality of tapered feed grooves which are recessed radially in said radial direction into said inner segment surface to define a radial groove depth wherein each said feed groove has closed sides defined by axially-extending side edges lying within said inner groove surface that are circumferentially spaced apart in a side-to-side circumferential direction to define a circumferential groove width, each of said feed grooves extending axially from said first end face between an open outer groove end at said first end face and a closed inner groove end spaced axially from said first end face to define an axial groove length, and which said feed grooves are configured to receive fluid axially into said open outer groove ends from said first fluid region, said radial groove depth of each of said feed grooves progressively decreasing along said axial groove length from said outer groove end to said inner groove end to generate said hydrodynamic fluid force during shaft rotation which acts radially outwardly away from said shaft and against said biasing force to reduce contact forces between said inner diameter of said seal ring and said opposing shaft surface when in contact and minimize formation of a clearance space therebetween as a result of shaft rotation, said radial groove depth also progressively decreasing in said side-to-side circumferential direction from a center groove portion toward at least one said side edge of said feed groove where said radial groove depth is shallower at said one side edge than said radial groove depth in said center groove portion, said axially-extending side edges of said feed grooves being circumferentially spaced apart and converging circumferentially sidewardly toward each other from said outer groove ends toward said inner groove ends, where said circumferential groove width is widest at said outer groove ends and said circumferential groove width is narrowest at said inner groove ends, such that said circumferential groove width for each said feed groove progressively decreases in said axial direction away from said outer groove end. 2. The segmented seal assembly according to claim 1, wherein said outer groove ends of said feed grooves open axially from said first end face of said seal ring and said radial groove depth is deepest at said first end face. 3. The segmented seal assembly according to claim 1, wherein said plurality of said feed grooves are provided in circumferentially spaced relation about said inner diameter to define lands which extend circumferentially between said side edges of adjacent said feed grooves and which are adapted for sealing contact with said outer shaft surface and separation therefrom during shaft rotation. 4. The segmented seal assembly according to claim 1, wherein said biasing arrangement comprises an annular biasing member extending circumferentially about said outer diameter to hold said ring segments together. 5. The segmented shaft seal according to claim 1, wherein said feed grooves are conical along an axial length thereof to define said radial groove depth which progressively decreases along said axial groove length and across said circumferential width. 6. The segmented seal assembly of claim 1, wherein each said feed groove has said side edges lying in said inner segment surfaces and extending axially uninterrupted within said inner segment surfaces between said outer and inner groove ends to define said closed sides of each said feed groove. 7. In a segmented seal assembly configured to be mounted on an equipment body for sealing an outer circumferential shaft surface of a rotatable shaft which is rotatable about a shaft axis extending in an axial direction, said seal assembly adapted to be positioned within an annular chamber disposed circumferentially about said shaft, said seal assembly including an annular seal ring which circumferentially extends about a center ring axis and is configured to extend circumferentially about said outer shaft surface to sealingly separate high and low pressure regions one from the other which said high and low pressure regions contain relatively high and low pressure fluid therein, said seal ring comprising a plurality of arcuate ring segments which are assembled within said seal assembly circumferentially adjacent to each other wherein each said shaft segment includes opposite first and second end faces, which face axially, and inner and outer segment surfaces which respectively face radially inwardly and outwardly toward and away from said center ring axis so as to be radially spaced apart and extend circumferentially to respectively define an inner diameter and an outer diameter of said seal ring extending about said center ring axis, said seal assembly including a biasing arrangement acting on said outer ring diameter to generate a respective biasing force on said ring segments which acts radially inwardly to maintain said ring segments in circumferentially adjacent relation with said inner diameter of said seal ring being adapted for sealing cooperation with said outer shaft surface, wherein the improvement comprises said seal ring including lift means for generating a hydrodynamic fluid force during shaft rotation which biases said ring segments radially outwardly against said biasing force, said lift means comprising a plurality of tapered feed grooves disposed on said inner surfaces of said ring segments which extend from open outer groove ends receiving said high pressure fluid to closed inner groove ends, said feed grooves being recessed radially in said inner segment surfaces so as to have a radial groove depth tapering radially inwardly along an axial groove length of said feed grooves to receive said high pressure fluid therein from said high pressure region to generate said hydrodynamic fluid force during shaft rotation which acts radially outwardly away from said shaft and against said biasing force to reduce contact forces between said inner diameter of said seal ring and said opposing shaft surface and minimize formation of a clearance space therebetween as a result of shaft rotation, said feed grooves being circumferentially spaced apart and being tapered wherein said radial groove depth of each said feed groove progressively decreases in said axial direction along said axial groove length from said outer groove end, where said radial groove depth is deepest, to said inner groove end, where said radial groove depth is shallower, and wherein said radial groove depth of each said feed groove also progressively decreases in a side-to-side direction from a center groove portion toward at least one said side edge of said feed groove where said radial groove depth is shallower at said one side edge than said radial groove depth in said center groove portion, each of said feed grooves having closed sides defined by axially extending opposite side edges lying in said respective inner segment surfaces which extend from said outer groove ends to said inner groove ends and converge circumferentially sideways toward each other to define a circumferential width of said feed grooves which progressively decreases from said outer end where said circumferential width is widest to said inner end thereof where said circumferential width is narrowest, and said inner groove ends terminating a partial distance across an axial width of said inner ring surface to define an annular sealing dam which is adapted for substantially continuous circumferential contact with said outer shaft surface. 8. The segmented seal assembly according to claim 7, wherein said outer groove ends of said feed grooves open axially toward said high pressure region to receive said high pressure fluid which circulates into said feed grooves through said open outer groove ends to define said hydrodynamic fluid force. 9. The segmented shaft seal assembly according to claim 7, wherein said feed grooves are conical along said axial groove length thereof to define said radial groove depth. 10. In a segmented shaft seal assembly having a holder and a plurality of arcuate ring segments disposed in circumferentially adjacent relation to define an annular seal ring which is supported by said holder, said seal ring having inner and outer diameters wherein said inner diameter is adapted for circumferential contact with an outer surface of a rotatable shaft, comprising the improvement wherein said ring segments are molded so as to have opposite first and second end faces which face in opposite axial directions and inner and outer segment surfaces which face radially inwardly and outwardly in opposite radial directions, said inner and outer segment surfaces respectively being aligned circumferentially with said ring segments disposed in circumferentially adjacent relation such that said inner and outer ring surfaces respectively define inner and outer circumferential ring surfaces of said seal ring having at least a constant inner diameter, said inner segment surfaces having respective tapered lift grooves which each extend axially in one said radial direction along a respective one of said inner segments from an open outer end at said first end face to a closed inner end spaced from said first end face in said axial direction, each said lift groove being recessed radially in said inner segment surface to define a radial groove depth which progressively decreases along an axial groove length extending away from said first end face to generate a hydrodynamic lift force during shaft rotation that acts radially outwardly away from said shaft to reduce contact forces between said inner ring diameter and said outer shaft surface, each said lift groove having said radial groove depth defined radially between said inner segment surface and a recessed groove surface, and having a circumferential width defined between opposite convergent side edges of said lift groove which said side edges are circumferentially spaced apart in a side-to-side direction, said side edges lying in said inner segment surface respectively so as to extend uninterrupted within said inner segment surface between said first end face and said closed inner end and define closed sides of said lift groove, each said lift groove having said open outer end which opens axially from said first end face to receive fluid therethrough and said closed inner end which terminates part way across said inner segment surface, said lift grooves tapering along said axial groove length such that the radial groove depth of said lift grooves progressively decreases along the axial groove length away from said open outer ends where said radial groove depth is deepest with said open outer ends being larger than said respective closed inner ends to permit removal of a mold die axially away from said first end face during manufacture, said radial groove depth defined between said recessed groove surface and said respective inner segment surface also progressively decreasing circumferentially from side to side so that said radial groove depth is shallower at said side edges than at a center groove portion disposed between said side edges, said side edges converging circumferentially toward each other in the side-to-side direction such that the circumferential width of said lift grooves progressively decreases in the side-to-side direction along the axial groove length extending away from said open outer ends which are wider than said closed inner ends. 11. The segmented seal assembly according to claim 10, wherein said outer segment surface has an arcuate channel having an open end and a closed end which said closed end terminates part way across an axial width of said outer segment surface, said open end having said circumferential width and said radial groove depth being greater at said open end than at said closed end to permit axial removal of a mold die during manufacture thereof. 12. The segmented seal assembly according to claim 11, wherein an annular spring is seated axially within said arcuate channel to hold said ring segments together in circumferentially adjacent relation. 13. The segmented seal assembly according to claim 10, wherein said radial groove depth tapers in the side-to-side direction so as to progressively decrease towards both of said side edges thereof. 14. The segmented seal assembly according to claim 10, wherein said holder is configured to fit within an equipment body. 15. The segmented seal assembly according to claim 10, wherein said holder is formed separate from and configured to be securely mounted on an equipment body.
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이 특허에 인용된 특허 (12)
Junker, Arnold, Circumferential ring seal assembly.
McNickle Alan D. (Sellersville PA) Hwang Mingfong (Lansdale PA) Pope Adam N. (Cincinnati OH), Seal for sealing an incompressible fluid between a relatively stationary seal and a movable member.
Haynes, George Perry; Manry, Jared Daniel, Bidirectional lift-off circumferential shaft seal segment and a shaft seal including a plurality of the segments.
O'Brien, Michael, Fluid transfer seal assemblies, fluid transfer systems, and methods for transferring process fluid between stationary and rotating components using the same.
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