US20140265151A1 - Circumferential Seal with Ceramic Runner - Google Patents

Abstract

The disclosure describes a circumferential seal applicable to turbine engines. The circumferential seal includes a ceramic runner, an annular seal ring, at least one tolerance ring, and a pair of sealing rings. The runner is circumscribed about a shaft or a carrier within a recess along the shaft and is bounded by a shoulder and a clamping ring. At least one non-sealing spring mechanism is disposed between and directly contacts the shoulder and the first end of the runner. A second end of the runner directly contacts the clamping ring. In other embodiments, at least one non-sealing spring mechanism is disposed between and directly contacts the second end and the clamping ring and the first end directly contacts the shoulder. An anti-rotation element is attached to the clamping ring, carrier, or shaft and extends into a slot or hole or slot along the runner. The spring(s) applies a biasing force onto the runner toward the clamping ring or shoulder. The annular seal ring is rotationally stationary and circumscribed about the runner. The tolerance ring(s) directly contacts the runner and the shaft. The runner is fixed to the shaft or carrier via the tolerance ring(s), anti-rotation element, and spring(s) so that the runner rotates with the shaft. The sealing rings directly contact the runner and the shaft along the annular gap about the tolerance ring(s).

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• This application is based upon and claims priority from Patent Cooperation Treaty Application No. PCT/US2013/040812 filed May 13, 2013 which further claims priority from U.S. Provisional Application No. 61/789,419 filed Mar. 15, 2013, both entitled Circumferential Seal with Ceramic Runner. The subject matters of the prior applications are incorporated in their entirety herein by reference thereto.
FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT
• None.
BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• The invention generally relates to a sealing device for turbine engines. Specifically, the invention is directed to a circumferential seal disposed about a rotatable shaft wherein a ceramic runner is attached to the shaft adjacent to a carbon sealing ring.
• 2. Background
• Seal assemblies are used in gas turbine engines to prevent or limit leakage of a fluid along the interface between a rotating shaft and an otherwise fixed element.
• By way of example,FIG. 1 shows a typicalcircumferential seal1 including a rotating component called a seal rotor2 and a non-rotating component called aseal stator3. The seal rotor2 is made of metal, is mounted to a rotatable shaft4, and has a radially outward facing sealingsurface5. Theseal stator3 includes aring6 made of metal mounted to thehousing7 and a sealingring8. The sealingring8 is made of carbon and includes an inward facingsealing surface10. Theseal stator3 and seal rotor2 are arranged so that the inward facingsealing surface10 circumscribes the outward facingsealing surface5. A smallradial gap9 is maintained between the sealingring8 and seal rotor2 to avoid damage to thesofter sealing ring8.
• A common problem associated with circumferential seals and bushings occurs as a result of variation in theradial gap9 between thesealing ring8 and seal rotor2. This variation is due in part to the mechanical growth of the seal rotor2 due to centrifugal effects, but more significantly due to a disparity in the thermal growth between the seal rotor2, typically composed of a material with a higher coefficient of thermal expansion, and thesealing ring8, typically composed of a material with a lower coefficient of thermal expansion.
• A variation in theradial gap9 produces an undesirable effect when it is too wide open or too narrow. If theradial gap9 is too large, then the flow of fluid between thesealing ring8 and the seal rotor2 increases so as to adversely affect pressures within the high and low pressure sections of a turbine engine, thereby reducing the performance and efficiency thereof. If the gap is too small, then contact between thesealing ring8 and seal rotor2 occurs and damage results to one or both components.
• In U.S. Pat. No. 6,322,081, Ullah et al. describes a circumferential seal with ceramic runner to address sealing challenges associated with a seal system incorporating materials with divergent thermal expansions.
• Referring now to theFIG. 2, asection11 of a gas turbine engine is shown including a rotatable shaft4 on which rotating engine components, such as theradial compressor wheel12, are mounted. Circumscribing the rotatable shaft4 is astationary housing7. Thestationary housing7 is mounted atop abearing13 having aninner race14 which is mounted on the rotatable shaft4. Disposed between thehousing7 and shaft4 is acircumferential seal15. Thecircumferential seal15 includes aseal stator3 having ametal ring6 mounted to thehousing7 and acarbon sealing ring8 mounted to its radial inward facing surface. Thecarbon sealing ring8 has a radially inward facingsealing surface10.
• Thecircumferential seal15 also includes asealing rotor16. Therotor16 includes aceramic runner17 having a radially outward facingsealing surface5 in rubbing contact with the radially inward facingsealing surface10 of the sealingring8 to control leakage across theradial gap9. At one axial end, therunner17 has a radially outward extendingflange18. At this same axial end, therunner17 has a radially inward extendingflange19 having axial faces adapted to receive an axial clamping load. The sealingrotor16 further includes two metallicannular clamping members20,21 for providing this clamping load.
• The first annular clamping member21 includes acylindrical portion22 having a radially inward extending flange23 at one end and a radially outward extending lip24 at the other end. The length and thickness of thecylindrical portion22 are selected to impart radial flexibility to the annular clamping member21 so that thecylindrical portion22 acts as a cantilevered beam rigidly fixed at the inward extending flange23.
• The secondannular clamping member20 has acylindrical portion25 with a radially inward extending flange26 at one end and anaxial face27 at the other end. Thecylindrical portion25 has a plurality of circumferentially extending slots (not shown) that impart axial flexibility to thecylindrical portion25 allowing it to compress and expand like a coil spring. Theceramic runner17 is flexibly clamped between theaxial face27 and outward extending lip24.
• Thecircumferential seal15 provides substantially improved sealing efficiency over metal seal rotors2 by virtue of theceramic runner17. The thermal growth of the ceramic is low due to its low coefficient of thermal expansion, thus enabling therunner17 to more closely track thesealing ring8 resulting in a more constantradial gap9 throughout the entire operating envelope of a turbine engine.
• Alternatively, because the frictional and wear properties of the ceramic-to-carbon interface are substantially improved over those of carbon-to-metal interfaces, theceramic runner17 could be in rubbing contact with thecarbon sealing ring8, thus either eliminating or reducing the need for cooling of theseal rotor16.
• Unfortunately, the clamping mechanism employed by Ullah et al. and other similar mechanisms know within the art are problematic in that, when used with hard ceramic runners, the runners are susceptible to fracture induced failures.
• In U.S. Pat. No. 7,905,495, Munson describes a circumferential seal with a ceramic runner for use within a turbine engine.
• Referring now toFIGS. 3-5, aseal assembly28 is shown includingcarbon sealing rings33 contacting aceramic seal runner38. Thecarbon sealing rings33 are housed within astator30 between aflange31 attached to thestator30 at a first end and aremovable locking ring32 at a second end. Thestator30 contacts and is attached to ahousing29 along the engine. Theseal runner38 is a cylinder or sleeve-shaped element residing about a portion of theshaft40. Theshaft40 is attached to ashaft structure39 so that theshaft structure39 and elements secured thereto rotate with theshaft40. A first end of theshaft40 includes aflange41 projecting from theshaft40 inFIGS. 3 and 4 or attached to aspool member45 inFIG. 5. Thespool member45 is further attached to theshaft structure39. The second end of theshaft40 includes alocking ring43 which is attached to theshaft40 in a removable fashion inFIGS. 3 and 4 or to thespool member45 inFIG. 5.
• Theseal runner38 is fixed to theshaft40, so as to rotate therewith, by applying a compressive force in the direction of theflange41 when thelocking ring43 is secured to theshaft40 orspool member45. InFIGS. 3-5, aface seal44 is provided between theseal runner38 andlocking ring43 to prevent gases from bypassing the seal formed between the inward facingsealing surfaces34 along thesealing rings33 and the outward facingsealing surface35 along theseal runner38. InFIG. 3, awasher42 is also provided between theseal runner38 and theflange41 to prevent gases from bypassing the seal formed between the inward facingsealing surfaces34 and the outward facingsealing surface35. Theface seal44 is axially compliant so that it is deformed in response to the relative changes in the length between theseal runner38 and theshaft40 andshaft structure39.
• The radial position of theseal runner38 is maintained by a pair ofresilient member36. InFIG. 3, eachresilient member36 includes a plurality ofplates37 each having deflectable, resilient fingers. InFIG. 4, eachresilient member36 is a ring with a u-shaped cross section. Theresilient members36 separately form a gas-tight seal within the cavity between theseal runner38 and theshaft structure39. InFIG. 5, eachresilient member36 is a ring with a u-shaped cross section attached to comprise a single structure.
• The assemblies taught by Munson are problematic for several reasons. First, attachment of theseal runner38 to theshaft40 between theflange41 and thecompliant face seal44 restricts or limits axial growth of theseal runner38 andshaft40, thereby allowing temperature-induced stress fractures to form along theseal runner38. Second, the sealing properties of theface seal44 are compromised by cyclic expansion and contraction of components within a turbine engine. Third, the sealing properties of theresilient members36 are compromised by cyclic expansion and contraction of components within a turbine engine.
• Accordingly, what is required is a means for attaching a ceramic runner to a rotatable metal shaft that allows the runner to be used in a circumferential seal system and avoids damage to the runner associated with cyclic expansion and contraction of components with a turbine engine.
• What is also required is a means for attaching a ceramic runner within a circumferential seal system to a rotatable metal shaft that allows for sealing between the runner and shaft while avoiding damage to the sealing surface during use.
• What is also required is a means for attaching a ceramic runner within a circumferential seal system which allows for axial movement of the ceramic runner while avoiding the problems of the related arts.
• What is also required is a means for attaching a ceramic runner within a circumferential seal system which avoids radial expansion of the ceramic runner resulting from the radial expansion of a rotatable metal shaft and components thereon.
SUMMARY OF THE INVENTION
• An object of the invention is to provide a means for attaching a ceramic runner to a rotatable metal shaft that allows the runner to be used in a circumferential seal system and avoids damage to the runner associated with cyclic expansion and contraction of components with a turbine engine.
• An object of the invention is to provide a means for attaching a ceramic runner within a circumferential seal system to a rotatable metal shaft that allows for sealing between the runner and shaft while avoiding damage to the sealing surface during use.
• An object of the invention is to provide a means for attaching a ceramic runner within a circumferential seal system which allows for axial movement of the ceramic runner while avoiding the problems of the related arts.
• An object of the invention is to provide a means for attaching a ceramic runner within a circumferential seal system which avoids radial expansion of the ceramic runner resulting from the radial expansion of a rotatable metal shaft and components thereon.
• In accordance with embodiments of the invention, the circumferential seal includes a ceramic runner, an annular seal ring, at least one tolerance ring, and a pair of sealing rings. The ceramic runner is circumscribed about a shaft within a recess along the shaft. The recess is bounded by a shoulder and a clamping ring. A first annular gap is disposed between a first end of the ceramic runner and the shoulder. A second end of the ceramic runner directly contacts the clamping ring. An anti-rotation pin is attached to the clamping ring and extends into a slot along the ceramic runner. At least one non-sealing spring mechanism is disposed between and directly contacts the shoulder and the first end along the first annular gap. The non-sealing spring mechanism applies a biasing force onto the ceramic runner toward the clamping ring. The annular seal ring is circumscribed about the ceramic runner and disposed within a seal housing so that the annular seal ring is stationary. The tolerance ring(s) directly contacts the ceramic runner and the shaft along a second annular gap between the ceramic runner and the shaft. The ceramic runner is fixed to the shaft via the tolerance ring(s), anti-rotation pin, and non-sealing spring mechanism so that the ceramic runner rotates with the shaft. The non-sealing spring mechanism expands and contracts in response to expansion and contraction of the ceramic runner. The pair of sealing rings directly contacts the ceramic runner and the shaft along the second annular gap. The tolerance ring(s) is disposed between the pair of sealing rings.
• In accordance with other embodiments of the invention, the non-sealing spring mechanism is a wave spring or a compression spring.
• In accordance with other embodiments of the invention, the non-sealing spring mechanism is compression springs separately disposed about the first annular gap and attached to the shoulder along the shaft.
• In accordance with other embodiments of the invention, each tolerance ring and each sealing ring is separately disposed within an equal number of annular grooves along the ceramic runner.
• In accordance with other embodiments of the invention, each tolerance ring and each sealing ring is separately disposed within an equal number of annular grooves along the shaft.
• In accordance with other embodiments of the invention, the annular seal ring forms a contact seal or a non-contact seal about the ceramic runner.
• In accordance with other embodiments of the invention, the sealing ring is an O-ring, a spring-energized seal, or a high-temperature metallic seal ring.
• In accordance with embodiments of the invention, the circumferential seal includes a ceramic runner, an annular seal ring, at least one tolerance ring, and a pair of sealing rings. The ceramic runner is circumscribed about a recess along a shaft. The recess is bounded by a shoulder and a clamping ring. A first annular gap is disposed between a second end of the ceramic runner and the clamping ring. A first end of the ceramic runner directly contacts the shoulder along the shaft. An anti-rotation pin is attached to the shoulder and extends into a slot along the ceramic runner. At least one non-sealing spring mechanism is disposed between and directly contacts the clamping ring and the second end along the first annular gap. At least one non-sealing spring mechanism applies a biasing force onto the ceramic runner toward the shoulder. The annular seal ring is circumscribed about the ceramic runner and disposed within a seal housing so that the annular seal ring is stationary. The tolerance ring(s) directly contacts the ceramic runner and the shaft along a second annular gap between the ceramic runner and the shaft. The ceramic runner is fixed to the shaft via the tolerance ring(s), anti-rotation pin, and non-sealing spring mechanism so that the ceramic runner rotates with the shaft. The non-sealing spring mechanism expands and contracts in response to expansion and contraction of the ceramic runner. The pair of sealing rings directly contacts the ceramic runner and the shaft along the second annular gap. The tolerance ring(s) is disposed between the pair of sealing rings.
• In accordance with other embodiments of the invention, the non-sealing spring mechanism is a wave spring or a compression spring.
• In accordance with other embodiments of the invention, the non-sealing spring mechanism is compression springs separately disposed about the first annular gap and attached to the clamping ring.
• In accordance with other embodiments of the invention, each tolerance ring and each sealing ring is separately disposed within an equal number of annular grooves along the ceramic runner.
• In accordance with other embodiments of the invention, each tolerance ring and each sealing ring is separately disposed within an equal number of annular grooves along the shaft.
• In accordance with other embodiments of the invention, the annular seal ring forms a contact seal or a non-contact seal about the ceramic runner.
• In accordance with other embodiments of the invention, the sealing ring is an O-ring, a spring-energized seal, or a high-temperature metallic seal ring.
• In accordance with embodiments of the invention, the circumferential seal includes a carrier, a ceramic runner, an annular seal ring, at least one tolerance ring, and a pair of sealing rings. The carrier is disposed about and directly contacts a shaft within a recess along the shaft. The carrier is rotatable with the shaft. The carrier has a shoulder at one end. The ceramic runner is circumscribed about the carrier and disposed between the shoulder and a clamping ring. A first annular gap is disposed between a first end of the ceramic runner and the shoulder. A second end of the ceramic runner directly contacts the clamping ring. An anti-rotation key is attached to the clamping ring and extends into a slot along the ceramic runner. At least one non-sealing spring mechanism directly contacts the shoulder and the first end along the first annular gap. The non-sealing spring mechanism applies a biasing force onto the ceramic runner toward the clamping ring. The annular seal ring is circumscribed about the ceramic runner and disposed within a seal housing so that the annular seal ring is stationary. The tolerance ring(s) directly contacts the ceramic runner and the carrier along a second annular gap between the ceramic runner and the carrier. The ceramic runner is fixed to the carrier via the tolerance ring(s), anti-rotation key, and non-sealing spring mechanism so that the ceramic runner rotates with the carrier. The non-sealing spring mechanism expands and contracts in response to expansion and contraction of the ceramic runner. The pair of sealing rings directly contacts the ceramic runner and the carrier along the second annular gap. The tolerance ring(s) is disposed between the pair of sealing rings.
• In accordance with other embodiments of the invention, the non-sealing spring mechanism is a wave spring or a compression spring.
• In accordance with other embodiments of the invention, the non-sealing spring mechanism is compression springs separately disposed about the first annular gap and attached to the shoulder.
• In accordance with other embodiments of the invention, each tolerance ring and each sealing ring is separately disposed within an annular groove along the carrier.
• In accordance with other embodiments of the invention, each tolerance ring and each sealing ring is separately disposed within an annular groove along the ceramic runner.
• In accordance with other embodiments of the invention, the annular seal ring forms a contact seal or a non-contact seal about the ceramic runner.
• In accordance with other embodiments of the invention, the sealing ring is an O-ring, a spring-energized seal, or a high-temperature metallic seal ring.
• In accordance with embodiments of the invention, the circumferential seal includes a carrier, a ceramic runner, an annular seal ring, at least one tolerance ring, and a pair of sealing rings. The carrier is disposed about and directly contacts a shaft within a recess along the shaft. The carrier is rotatable with the shaft. The carrier has a shoulder at one end. The ceramic runner is circumscribed about the carrier and disposed between the shoulder and a clamping ring. A first annular gap is disposed between a second end of the ceramic runner and the clamping ring. A first end of the ceramic runner directly contacts the shoulder. An anti-rotation key is attached to the shoulder and extends into a slot along the ceramic runner. At least one non-sealing spring mechanism directly contacts the clamping ring and the second end along the first annular gap. The non-sealing spring mechanism applies a biasing force onto the ceramic runner toward the shoulder. The annular seal ring is circumscribed about the ceramic runner and disposed within a seal housing so that the annular seal ring is stationary. The tolerance ring(s) directly contacts the ceramic runner and the carrier along a second annular gap between the ceramic runner and the carrier. The ceramic runner is fixed to the carrier via the tolerance ring(s), anti-rotation key, and non-sealing spring mechanism so that the ceramic runner rotates with the carrier. The non-sealing spring mechanism expands and contracts in response to expansion and contraction of the ceramic runner. The pair of sealing rings directly contacts the ceramic runner and the carrier along the second annular gap. The tolerance ring(s) is disposed between the pair of sealing rings.
• In accordance with other embodiments of the invention, the non-sealing spring mechanism is a wave spring or a compression spring.
• In accordance with other embodiments of the invention, the non-sealing spring mechanism is compression springs separately disposed about the first annular gap and attached to the clamping ring.
• In accordance with other embodiments of the invention, each tolerance ring and each sealing ring is separately disposed within an annular groove along the carrier.
• In accordance with other embodiments of the invention, each tolerance ring and each sealing ring is separately disposed within an annular groove along the ceramic runner.
• In accordance with other embodiments of the invention, the annular seal ring forms a contact seal or a non-contact seal about the ceramic runner.
• In accordance with other embodiments of the invention, the sealing ring is an O-ring, a spring-energized seal, or a high-temperature metallic seal ring.
• In accordance with embodiments of the invention, the circumferential seal includes a carrier, a ceramic runner, an annular seal ring, at least one tolerance ring, and a pair of sealing rings. The carrier is disposed about and directly contacts a shaft within a recess along the shaft. The carrier is rotatable with the shaft. The carrier has a shoulder at one end. The ceramic runner is circumscribed about the carrier and disposed between the shoulder and a clamping ring. A first annular gap is disposed between a first end of the ceramic runner and the shoulder. A second end of the ceramic runner directly contacts the clamping ring. An anti-rotation screw is attached to the carrier and extends into a hole along the ceramic runner. At least one non-sealing spring mechanism directly contacts the shoulder and the first end along the first annular gap. The non-sealing spring mechanism applies a biasing force onto the ceramic runner toward the clamping ring. The annular seal ring is circumscribed about the ceramic runner and disposed within a seal housing so that the annular seal ring is stationary. The tolerance ring(s) directly contacts the ceramic runner and the carrier along a second annular gap between the ceramic runner and the carrier. The ceramic runner is fixed to the carrier via the tolerance ring(s), anti-rotation screw, and non-sealing spring mechanism so that the ceramic runner is rotatable with the carrier. The non-sealing spring mechanism expands and contracts in response to expansion and contraction of the ceramic runner. At least one sealing ring directly contacts the ceramic runner and the carrier along the second annular gap. The tolerance ring(s) and anti-rotation screw are disposed between the pair of sealing rings.
• In accordance with other embodiments of the invention, the non-sealing spring mechanism is a wave spring or a compression spring.
• In accordance with other embodiments of the invention, the non-sealing spring mechanism is compression springs separately disposed about the first annular gap and attached to the shoulder.
• In accordance with other embodiments of the invention, each tolerance ring and one sealing ring is separately disposed within an annular groove along the carrier and another sealing ring is disposed within another annular groove along the clamping ring.
• In accordance with other embodiments of the invention, each tolerance ring and one sealing ring is separately disposed within an annular groove along the ceramic runner and another sealing ring is disposed within another annular groove along the clamping ring.
• In accordance with other embodiments of the invention, the annular seal ring forms a contact seal or a non-contact seal about the ceramic runner.
• In accordance with other embodiments of the invention, the sealing ring is an O-ring, a spring-energized seal, or a high-temperature metallic seal ring.
• In accordance with embodiments of the invention, the circumferential seal includes a carrier, a ceramic runner, an annular seal ring, at least one tolerance ring, and a pair of sealing rings. The carrier is disposed about and directly contacts a shaft within a recess along the shaft. The carrier is rotatable with the shaft. The carrier has a shoulder at one end. A ceramic runner is circumscribed about the carrier and disposed between the shoulder and a clamping ring. A first annular gap is disposed between a second end of the ceramic runner and the clamping ring. A first end of the ceramic runner directly contacts the shoulder. An anti-rotation screw is attached to the carrier and extends into a hole along the ceramic runner. At least one non-sealing spring mechanism directly contacts the clamping ring and the second end along the first annular gap. The non-sealing spring mechanism applies a biasing force onto the ceramic runner toward the shoulder. The annular seal ring is circumscribed about the ceramic runner and disposed within a seal housing so that the annular seal ring is stationary. The tolerance ring(s) directly contacts the ceramic runner and the carrier along a second annular gap between the ceramic runner and the carrier. The ceramic runner is fixed to the carrier via the tolerance ring(s), anti-rotation screw, and non-sealing spring mechanism so that the ceramic runner is rotatable with the carrier. The non-sealing spring mechanism expands and contracts in response to expansion and contraction of the ceramic runner. At least one sealing ring directly contacts the ceramic runner and the carrier along the second annular gap. The tolerance ring(s) and anti-rotation screw are disposed between the pair of sealing rings.
• In accordance with other embodiments of the invention, the non-sealing spring mechanism is a wave spring or a compression spring.
• In accordance with other embodiments of the invention, the non-sealing spring mechanism is compression springs separately disposed about the first annular gap and attached to the clamping ring.
• In accordance with other embodiments of the invention, each tolerance ring and one sealing ring is separately disposed within an annular groove along the carrier and another sealing ring is disposed within another annular groove along the clamping ring.
• In accordance with other embodiments of the invention, each tolerance ring and one sealing ring is separately disposed within an annular groove along the ceramic runner and another sealing ring is disposed within another annular groove along the clamping ring.
• In accordance with other embodiments of the invention, the annular seal ring forms a contact seal or a non-contact seal about the ceramic runner.
• In accordance with other embodiments of the invention, the sealing ring is an O-ring, a spring-energized seal, or a high-temperature metallic seal ring.
• During operation of a turbine engine, the shaft rotates with respect to the annular seal ring. The ceramic runner is configured to rotate with the shaft via the non-sealing spring mechanism, anti-rotation element, and tolerance ring(s). The non-sealing spring mechanism applies an axial load onto the ceramic runner biasing the runner against the clamping ring attached to the shaft. Friction between the ceramic runner and clamping ring resists relative rotational motion between the runner and shaft. Relative motion is further avoided by the anti-rotation element fixed to and movable with the shaft. The anti-rotation element contacts the ceramic runner thereby arresting rotation between runner and shaft. Contact by the tolerance rings between the ceramic runner and shaft or a carrier along the shaft further resists relative rotational motion between the runner and shaft.
• In one of its aspects, the invention utilizes a spring mechanism which deflects or compresses axially along the length of the shaft to accommodate thermal expansion axially along the ceramic runner during operation of the turbine engine so as to minimize stresses within the ceramic runner thereby minimizing the possibility of stress induced failures.
• In other of its aspects, the invention utilizes a spring mechanism which allows the ceramic runner to expand independently relative to the shaft and/or carrier so as to minimize stresses within the ceramic runner thereby minimizing the possibility of stress induced failures.
• In other of its aspects, the invention utilizes sealing rings between the ceramic runner and shaft or a carrier along the shaft which prevent oil leakage under the ceramic runner thereby minimizing oil coking under the runner.
• In other of its aspects, the invention utilizes sealing rings between the ceramic runner and shaft or a carrier along the shaft about the tolerance ring which prevent oil from contacting the tolerance ring(s) thereby avoiding slippage between the runner and shaft or carrier.
• In other of its aspects, the invention utilizes one or more sealing rings between the ceramic runner and shaft or a carrier along the shaft to radially deflect and accommodate changes in the clearance between the runner and shaft or carrier as the shaft and/or carrier expands thereby avoiding radial expansion by and damage to the runner.
• In other of its aspects, the invention utilizes one or more gapped tolerance rings between the ceramic runner and shaft or carrier which expands circumferentially so as to accommodate changes in the clearance between the runner and shaft or carrier as the shaft and/or carrier expands thereby avoiding radial expansion by and damage to the runner.
• In other of its aspects, the invention separates axial functionality of the spring mechanism from sealing function of the sealing rings thereby minimizing degradation of the sealing rings by thermally induced expansion and contraction cycles within a gas turbine engine.
• In other of its aspects, the invention separates radial functionality of the tolerance ring(s) from sealing function of the sealing rings thereby minimizing degradation of the sealing rings by thermally induced expansion and contraction cycles within a gas turbine engine.
• The above and other objectives, features, and advantages of the embodiments of the invention will become apparent from the following description read in connection with the accompanying drawings, in which like reference numerals designate the same or similar elements.
BRIEF DESCRIPTION OF THE DRAWINGS
• Additional aspects, features, and advantages of the invention will be understood and will become more readily apparent when the invention is considered in the light of the following description made in conjunction with the accompanying drawings.
• FIG. 1 is a cross-sectional view illustrating a circumferential seal with metal rotor as described by Ullah et al. in U.S. Pat. No. 6,322,081.
• FIG. 2 is a cross-sectional view illustrating a circumferential seal with ceramic rotor as described by Ullah et al. in U.S. Pat. No. 6,322,081.
• FIG. 3 is a cross-section view illustrating a circumferential seal with a ceramic runner attached compressively along a shaft between a flange and a locking ring and radially supported along the shaft via a pair of resilient members each having a plurality of plates as described by Munson in U.S. Pat. No. 7,905,395.
• FIG. 4 is a cross-section view illustrating a circumferential seal with a ceramic runner attached compressively along a shaft between a flange and a locking ring and radially supported along the shaft via a pair of resilient members each being a ring with u-shaped cross section as described by Munson in U.S. Pat. No. 7,905,395.
• FIG. 5 is a cross-section view illustrating a circumferential seal with a ceramic runner attached compressively along a spool member between a flange and a locking ring and radially supported along the spool member via a pair of resilient members each being a ring with u-shaped cross section which form a single structure as described by Munson in U.S. Pat. No. 7,905,395.
• FIG. 6ais a cross-section view illustrating a circumferential seal with a ceramic runner recessed along a rotatable shaft and attached thereto via at least one anti-rotation pin and an annular spring wherein sealing and tolerance rings are disposed between the runner and shaft within annular grooves along the runner in accordance with an embodiment of the invention.
• FIG. 6bis a cross-section view illustrating the anti-rotation pin inFIG. 6awithin a slot or hole along the ceramic runner in accordance with an embodiment of the invention.
• FIG. 6cis a side view illustrating the tolerance ring inFIG. 6awith a gap in accordance with an embodiment of the invention.
• FIG. 6dis a cross-section view illustrating a circumferential seal with a ceramic runner recessed along a rotatable shaft and attached thereto via at least one anti-rotation pin and an annular spring wherein the spring mechanism is provided between the ceramic runner and a clamping ring in accordance with an embodiment of the invention.
• FIG. 7ais a cross-section view illustrating a circumferential seal with a ceramic runner recessed along a rotatable shaft and attached thereto via at least one anti-rotation pin and an annular spring wherein sealing and tolerance rings are disposed between the runner and shaft within annular grooves along the shaft in accordance with an embodiment of the invention.
• FIG. 7bis a cross section view illustrating a compression spring disposed between the ceramic runner and shaft inFIG. 7ain accordance with an embodiment of the invention.
• FIG. 7cis a cross-section view illustrating several compression springs each within a hole along a portion of the shaft in accordance with an embodiment of the invention.
• FIG. 8ais a cross-section view illustrating a circumferential seal with a ceramic runner disposed along a carrier recessed along a rotatable shaft and attached to the carrier via at least one key and a plurality of compression springs wherein sealing and tolerance rings are disposed between the runner and shaft within annular grooves along the carrier in accordance with an embodiment of the invention.
• FIG. 8bis a cross-section view illustrating the key inFIG. 8awithin a slot along the ceramic runner in accordance with an embodiment of the invention.
• FIG. 8cis a cross-section view illustrating several compression springs each within a hole along a portion of the carrier in accordance with an embodiment of the invention.
• FIG. 8dis a cross section view illustrating an annular spring disposed between the ceramic runner and carrier inFIG. 8ain accordance with an embodiment of the invention.
• FIG. 8eis a cross-section view illustrating a circumferential seal with a ceramic runner disposed along a carrier recessed along a rotatable shaft wherein the spring mechanism is disposed between the ceramic runner and a clamping ring in accordance with an embodiment of the invention.
• FIG. 9ais a cross-section view illustrating a circumferential seal with a ceramic runner disposed along a carrier recessed along a rotatable shaft and attached to the carrier via at least one anti-rotation screw and a plurality of compression springs wherein a first sealing ring and tolerance ring are disposed between the runner and shaft within annular grooves along the shaft and a second sealing ring is disposed between the runner and a clamping ring along a groove within the clamping ring in accordance with an embodiment of the invention.
• FIG. 9bis a cross-section view illustrating the anti-rotation screw inFIG. 9adisposed within a hole along the carrier in accordance with an embodiment of the invention.
• FIG. 9cis a cross-section view illustrating the anti-rotation screw inFIG. 9adisposed within a hole along the ceramic runner in accordance with an embodiment of the invention.
• FIG. 9dis a cross-section view illustrating a circumferential seal with a ceramic runner disposed along a carrier recessed along a rotatable shaft and attached to the carrier via at least one anti-rotation screw and a plurality of compression springs wherein a first sealing ring and tolerance ring are disposed between the runner and shaft within annular grooves along the shaft and a second sealing ring is disposed between the runner and the carrier along a groove within the carrier in accordance with an embodiment of the invention.
• FIG. 9eis a cross-section view illustrating a circumferential seal with a ceramic runner disposed along a carrier recessed along a rotatable shaft wherein a spring mechanism is disposed between the ceramic runner and a clamping ring in accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
• Reference will now be made in detail to several embodiments of the invention that are illustrated in the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts. The drawings are in simplified form and are not to precise scale.
• While features of various embodiments are separately described throughout this document, it is understood that such features could be combined to form a single embodiment.
• Referring now toFIGS. 6aand7a, thecircumferential seal46 is illustrated for descriptive purposes along an upper half of anexemplary shaft57 rotatable about acenterline67 along a turbine engine. While theshaft57 is generally represented as a cylindrical-shaped element, other configurations are possible.
• Theouter diameter100 of theshaft57 is shown including arecess98. Therecess98 could include one or more regions along theshaft57 each having a diameter smaller than theouter diameter100 of theshaft57. Theexemplary shafts57 inFIGS. 6aand7ahave arecess98 which includes three sections arranged end-to-end in a stepwise fashion, whereby the first section accommodates aceramic runner52, the second section accommodates a clampingring74, and the third section accommodates a lockingring75. The clampingring74 and lockingring75 are composed of materials suitable for use within a turbine engine. Materials should be wear, failure, and temperature resistant. Exemplary compositions include metals, preferably compositions of steel. The lockingring75 secures the various components described herein to theshaft57 about therecess98. It is understood that therecess98 could include one or more sections as well as other shapes and designs which facilitate attachment of elements required to provide circumferential sealing along ashaft57.
• The interface between theouter diameter100 of theshaft57 and theouter diameter62 of therecess98 is defined by afirst shoulder55. Therecess98 could include additional shoulders depending on the profile of therecess98, although such features are optional and design dependent. For example, therecess98 inFIGS. 6aand7ais shown with asecond shoulder56 at the interface between the regions for theceramic runner52 and clampingring74 formed at the discontinuity of theouter diameters62,79. Thesecond shoulder56 acts as a mechanical stop which fixes the clampingring74 at a prescribed distance from thefirst shoulder55. A clearance fit could be provided between theouter diameter79 of theshaft57 andinner diameter83 along the clampingring74 so that the clampingring74 is slidable with respect to theshaft57. The clampingring74 is secured to theshaft57 via the lockingring75 which could include threads along itsinner diameter84 which engage a complementary thread arrangement along theouter diameter80 of theshaft57. In another example, therecess98 at the interface between the regions for the clampingring74 and lockingring75 is shown without a shoulder because these regions includeouter diameters79,80 which are approximately equal.
• Theceramic runner52 is a cylindrically-shaped or sleeve-shaped element which is slid onto theshaft57 during assembly so as to circumscribe theshaft57 about therecess98. Theceramic runner52 is composed of a ceramic composition suitable for use within a turbine engine. In preferred embodiments, the ceramic composition should be wear, failure, and temperature resistant. Exemplary, non-limiting compositions include silicon nitride and silicon carbide.
• Theceramic runner52 has aninner diameter61 which is larger than theouter diameter62 of theshaft57 along therecess98 resulting in a secondannular gap72 which avoids direct contact between theceramic runner52 andshaft57. The distance between afirst end53 and asecond end54 of theceramic runner52 is less than the axial distance between thefirst shoulder55 andsecond shoulder56. Thefirst end53 is positioned adjacent to thefirst shoulder55 so that a firstannular gap73 separates thefirst end53 from thefirst shoulder55. The axial length of the firstannular gap73 is sized to accommodate a spring mechanism. The spring mechanism provides no sealing functionality. Although spring mechanisms are described herein, it is understood that such mechanisms could include other non-sealing devices which at least resist compression and are resilient. Thesecond end54 directly contacts the clampingring74 so that thesecond end54 is generally aligned with thesecond shoulder56.
• In some embodiments, the spring mechanism could be a singleannular spring58, as represented inFIGS. 6aand7a. Exemplaryannular springs58 include a wave spring or a compression spring or the like which circumscribe theshaft57 within the firstannular gap73. The length of theannular spring58 in its uncompressed state requires theannular spring58 to be partially compressed when assembled between theceramic runner52 andshaft57. Theannular spring58 is compressed by contact with thefirst shoulder55 at one end of theannular spring58 and thefirst end53 at another end of theannular spring58. In its partially compressed state, theannular spring58 communicates a biasingforce99 axially onto theceramic runner52 thereby pressing theceramic runner52 onto the clampingring74. The biasingforce99 is preferred to maintain contact between thesecond end54 of theceramic runner52 and the clampingring74 during operation of a turbine engine, thereby avoiding axial separation between theceramic runner52 and clampingring74 which could occur because of thermally induced expansion and contraction of components within the engine. The biasingforce99 also resists rotational sliding motion between theceramic runner52 and clampingring74 at thesecond end54. Theannular spring58 is partially compressed at or below ambient conditions so as to allow for further compression of theannular spring58 during operation of a turbine engine. This feature allows theannular spring58 to expand and contract with axial expansion and contraction of theceramic runner52 as theceramic runner52 and other components heat and cool.
• In other embodiments, the spring mechanism could include a plurality of compression springs88 or the like, as represented inFIGS. 7band7c. Eachcompression spring88 is axially aligned along the direction of theshaft57 as shown inFIG. 7b. The compression springs88 are further separately disposed about the diameter of theshaft57 along thefirst shoulder55 as generally shown inFIG. 7c, so as to communicate a biasingforce99 symmetrically about theceramic runner52 in the axial direction. One end of eachcompression spring88 could reside within a complementary shapedhole94 so that a portion of thecompression spring88 extends into the firstannular gap73 with sufficient length to contact thefirst end53 along theceramic runner52. Thecompression spring88 could be mechanically fixed to thehole94 via an interference fit or freely movable within thehole94. The compression springs88 are preferred to be sufficiently long so that each is partially compressed when assembled between theshaft57 andceramic runner52. Partial compression of thecompression spring88 maintains a biasingforce99 onto theceramic runner52 so that thesecond end54 of theceramic runner52 is biased toward and contacts the clampingring74. The biasingforce99 maintains contact between thesecond end54 of theceramic runner52 and the clampingring74 during operation of a turbine engine, thereby avoiding axial separation thereof because of thermally induced expansion and contraction ofceramic runner52 and other components within the engine. The biasingforce99 also resists rotational sliding motion between theceramic runner52 and clampingring74 at thesecond end54. The compression springs88 are partially compressed at or below ambient conditions so as to allow for further compression of the compression springs88 during operation of a turbine engine. This feature allows the compression springs88 to expand and contract with expansion and contraction of theceramic runner52 as theceramic runner52 and other components heat and cool.
• In other embodiments, thefirst end53 could directly contact thefirst shoulder55 and the spring mechanism, either theannular spring58 or the compression springs88, is disposed between thesecond end54 and clampingring74, as generally represented inFIG. 6d. The firstannular gap73 now resides between thesecond end54 and clampingring74. The biasingforce99 is directed toward theshoulder55. Theanti-rotation pin76 partially resides within ahole77 and is attached to theshaft57 along thefirst shoulder55 so as to extend toward theceramic runner52. Another portion of theanti-rotation pin76 resides within aslot78 along thefirst side53. The spring mechanisms could be attached to the clampingring74 in a similar manner as otherwise described herein for attachment to theshaft57.
• Referring again toFIGS. 6aand7a, the secondannular gap72 between theinner diameter61 of theceramic runner52 andouter diameter62 of theshaft57 is shown with a pair of tolerance rings70,71. Although two tolerance rings70,71 are shown and described, it is understood that the secondannular gap72 could include one or more such rings. The tolerance rings70,71 are generally described as a ring-shaped element with corrugations along an inward face or an outward face and with agap87, the latter feature represented inFIG. 6c(corrugated structure not shown). Tolerance rings70,71 provide no sealing functionality. When attached between theinner diameter61 andouter diameter62 along thegap72, the tolerance rings70,71 conform to the bore and are self-retaining thereby resisting rotational slippage between theceramic runner52 andshaft57. The tolerance rings70,71 could allow for axial slippage so as to avoid stresses within theceramic runner52. Exemplary tolerance rings70,71 are the BN Series devices sold by USA Tolerance Rings of Pennington, N.J. (United States). The tolerance rings70,71 maintain proper fit between theceramic runner52 andshaft57 by expanding circumferentially to the radial clearance between theinner diameter61 andouter diameter62 by closing thegap87. This functionality avoids radial expansion of theceramic runner52 which could damage therunner52. Eachtolerance ring70,71 resides within anannular groove63,65, respectively. Theannular grooves63,65 are disposed along theinner diameter61 of theceramic runner52 as shown inFIG. 6aor along theouter diameter52 of theshaft57 as shown inFIG. 7a. The depth of eachannular groove63,65 should allow assembly of theceramic runner52 onto theshaft57 and proper placement of the tolerance rings70,71 along theshaft57 while ensuring sufficient contact between the tolerance rings70,71 and inner andouter diameters61,62 for proper function of the tolerance rings70,71. Theannular grooves63,65 should be at least as wide as the tolerance rings70,71, preferably providing a tolerance fit which allows eachtolerance ring70,71 to be secured within the respectiveannular groove63,65.
• Referring again toFIGS. 6aand7a, the secondannular gap72 between theinner diameter61 of theceramic runner52 andouter diameter62 of theshaft57 is shown with a pair of sealing rings68,69. Sealing rings68,69 could include devices known within the art, examples including, but not limited to, multi-directional O-rings, unidirectional spring-energized seals, high-temperature metallic seal rings, or other comparable devices sold by the Parker Hannifin Corporation located in North Haven, Conn. (United States) or other suppliers. Other exemplary seals include those sold under the Trademark OMNISEAL® by Saint-Gobain Performance Plastics Corporation of Aurora, Ohio (United States). When assembled between theinner diameter61 andouter diameter62 about the secondannular gap72, the sealing rings68,69 conform to the bore thereby further resisting rotational slippage between theceramic runner52 andshaft57. The seal rings68,69 could allow for axial slippage so as to avoid stresses within theceramic runner52. Each sealingring68,69 resides within anannular groove64,66, respectively. Theannular grooves64,66 are disposed along theinner diameter61 of theceramic runner52 as shown inFIG. 6aor along theouter diameter52 of theshaft57 as shown inFIG. 7a. The depth of eachannular groove64,66 should be sufficiently deep so as to allow assembly of theceramic runner52 onto theshaft57 and proper placement of the sealing rings68,69 along theshaft57 while ensuring sufficient contact between the sealing rings68,69 and inner andouter diameters61,62 for proper function of the sealing rings68,69. Thegrooves64,66 should be at least as wide as the sealing rings68,69, preferably with a tolerance fit allowing each sealingring68,69 to be secured within the respectiveannular groove64,66.
• The sealing rings68,69 are disposed about the tolerance rings70,71, as represented inFIGS. 6aand7a. The sealing rings68,69 are oriented along the secondannular gap72 so that the sealingdirection101 of the sealing rings68,69 avoids or at least minimizes oil and other contaminants within the higher and/or lower pressure sides81,82 from entering the secondannular gap72 and interacting with the tolerance rings70,71. This feature minimizes degradation to the performance of the tolerance rings70,71 caused by oil and other contaminants and further minimizes oil coking under theceramic runner52.
• The clampingring74 further includes at least oneanti-rotation pin76. Theanti-rotation pin76 could reside within a complementary shapedhole77 along the clampingring74 so that a portion of theanti-rotation pin76 extends toward theceramic runner52. Theanti-rotation pin76 could be mechanically fixed to thehole77 via an interference fit or slidable therein via a clearance fit. The portion of theanti-rotation pin76 extending from the clampingring74 could reside within aslot78 along theceramic runner52. Theslot78 could extend from theinner diameter61 of theceramic runner52 and partially traverse the thickness of theceramic runner52 in the direction of the outwardfacing sealing surface60, as represented inFIG. 6b. Theslot78 is dimensioned to avoid contact with the end and sides of theanti-rotation pin76, seeFIGS. 6aand6b, respectively. Theanti-rotation pin76 could contact aside wall102, the latter shown inFIG. 6b, along theslot78 when theceramic runner52 rotates relative to the clampingring74. The degree of rotation before contact between theanti-rotation pin76 andside wall102 is determined by the clearance therebetween, which is design dependent.
• Anannular seal ring49 is circumferentially disposed about the outwardfacing sealing surface60 of theceramic runner52. Theannular seal ring49 includes an inwardfacing sealing surface59 which interacts with the outwardfacing sealing surface60 to form the circumferential sealing of the present invention. Theannular seal ring49 is a ring-shaped element with or without segmentation. In some embodiments, the inwardfacing sealing surface59 could physically contact the outwardfacing sealing surface60 during rotation of theceramic runner52 andshaft57 to provide a contact seal. In other embodiments, the inwardfacing sealing surface59 and outward facing sealingsurface60 could be separated by a gap to form a non-contact seal. In yet other embodiments, the outwardfacing sealing surface60 could include hydrodynamic pockets which form a thin-film between inward and outward facing sealing surfaces59,60 during rotation of theceramic runner52.
• Theannular seal ring49 resides within aseal housing47 and is secured thereto via asupport ring50 and a retainingring51 or other like elements via methods and designs known within the art. Theannular seal ring49 is stationary rotationally with respect to theseal housing47. As such, theannular seal ring49 does not rotate with respect to theseal housing47. Theannular seal ring49 could move radially inward and outward to track radial excursions of theceramic runner52. Theseal housing47 is secured to ahousing48 comprising a turbine engine. Both sealhousing47 andhousing48 are shown in a generalized form for descriptive purposes only and are not intended to limit the scope of the claimed invention. Arrangement of theannular seal ring49, sealhousing47, andhousing48 about theceramic runner52 andshaft57 generally defines ahigher pressure side81 and alower pressure side82. Thehigher pressure side81 could define the air or gas side within a turbine engine. Thelower pressure side82 could define the bearing or oil side within a turbine engine.
• Referring again toFIGS. 6aand7a, the outwardfacing sealing surface60 along theceramic runner52 is shown approximately radially aligned with theouter diameter100 of theshaft57. However, it is understood that outward facing sealingsurface60 could extend above or be depressed below theouter diameter100 in other embodiments of the invention. In yet other embodiments, it is possible for the outwardfacing sealing surface60 to move radially inward and outward with respect to theouter diameter100 during operation of a turbine engine.
• Referring now toFIG. 8a, thecircumferential seal46 is illustrated for descriptive purposes along an upper half of anexemplary shaft57 along a turbine engine rotatable about acenterline67. In this embodiment, aceramic runner52 is attached to acarrier91 to form acartridge90. Thecartridge90 facilitates assembly of components comprising thecircumferential seal46 prior to attachment to ashaft57. This approach simplifies assembly and repair of a turbine engine.
• Theouter diameter100 of theshaft57 is shown including arecess98. Therecess98 could include one or more regions along theshaft57 each having a diameter smaller than theouter diameter100. Theexemplary shaft57 has arecess98 which includes a single section to accommodate alocking ring75 and acarrier91, the latter supporting aceramic runner52 and aclamping ring74. The clampingring74 and lockingring75 are composed of materials suitable for use within a turbine engine. Materials should be wear, failure, and temperature resistant. Exemplary compositions include metals, preferably compositions of steel. The lockingring75 secures thecarrier91 with the various components described herein to theshaft57 about therecess98. It is understood that therecess98 could include one or more sections as well as other shapes and designs which facilitate attachment of elements required to provide circumferential sealing along ashaft57.
• The interface between theouter diameter100 of theshaft57 and theouter diameter62 of therecess98 defines afirst shoulder55. Therecess98 could include additional shoulders depending on the profile of therecess98, although such features are optional and design dependent. For example, therecess98 could include other shoulders each defined by a discontinuity where two outer diameters differ.
• Thecarrier91 is a ring-shaped element with aflange104 which extends perpendicular from one end of anannular ring105. In some embodiments, a clearance fit is provided for assembly purposes between theouter diameter62 of theshaft57 andinner diameter85 of thecarrier91 so that thecarrier91 is slidable with respect to theshaft57. In other embodiments, an interference fit is provided between theouter diameter62 and theinner diameter85 and thecarrier91 is heated to open theinner diameter85 prior to sliding thecarrier91 onto theshaft57. Thecarrier91 is then cooled to fix thecarrier91 to theshaft57. Theflange104 should contact theshoulder55 in addition to theannular ring105 contacting the surface of theshaft57. Thecarrier91 is composed of materials suitable for use within a turbine engine. Materials should be wear, failure, and temperature resistant. Exemplary compositions include metals, preferably compositions of steel with a coefficient of thermal expansion comparable to that of theshaft57 so thatcarrier91 tracks the expansion and contraction of theshaft57.
• Thecarrier91 could likewise include one or more shoulders along the surface of theannular ring105. The interface between theannular surface107 along thecarrier91 and theouter diameter106 of thecarrier91 defines afirst shoulder92. Thecarrier91 could also include a first segment with anouter diameter106 and a second segment with anouter diameter86. Theouter diameter106 could be larger than the otherouter diameter86 so that asecond shoulder103 is provided at the discontinuity between the two outer surfaces. A clearance fit could be provided between theouter diameter86 of thecarrier91 andinner diameter83 along the clampingring74 so that the clampingring74 is slidable with respect to thecarrier91. Thecarrier91 and clampingring74 are secured to theshaft57 via the lockingring75. The lockingring75 contacts both the clampingring74 and theend93 of thecarrier91 as illustrate inFIG. 8a. The lockingring75 includes threads along itsinner diameter84 which engage a complementary thread arrangement along theouter diameter80 of theshaft57. The force applied by the lockingring75 onto thecarrier91 and clampingring74 should be sufficient to prevent relative motion with respect to theshaft57.
• Theceramic runner52 is a cylindrically-shaped or sleeve-shaped element which is slid onto theshaft57 during assembly so as to circumscribe thecarrier91. Theceramic runner52 is composed of a ceramic composition suitable for use within a turbine engine. In preferred embodiments, the ceramic composition should be wear, failure, and temperature resistant. Exemplary, non-limiting compositions include silicon nitride and silicon carbide.
• Theceramic runner52 has aninner diameter61 which is larger than theouter diameter106 of thecarrier91 resulting in a secondannular gap72 which avoids direct contact between theceramic runner52 andcarrier91. The distance between afirst end53 and asecond end54 of theceramic runner52 is less than the axial distance between thefirst shoulder92 andsecond shoulder103. Thefirst end53 is positioned adjacent to thefirst shoulder92 so that a firstannular gap73 separates thefirst end53 from thefirst shoulder92. The axial length of the firstannular gap73 is sized to accommodate a spring mechanism. The spring mechanism provides no sealing functionality. Although spring mechanisms are described herein, it is understood that such mechanisms could include other non-sealing devices which at least resist compression and are resilient. Thesecond end54 directly contacts the clampingring74 so that thesecond end54 is generally aligned with thesecond shoulder103.
• In some embodiments, the spring mechanism could include a plurality of compression springs88 as represented inFIG. 8aand generally described inFIGS. 7band7c. Eachcompression spring88 is axially aligned along the direction of theshaft57. The compression springs88 are further separately disposed about theshaft57 along theflange104 of thecarrier91, as generally shown inFIG. 8c, so as to communicate a biasingforce99 symmetrically about theceramic runner52 in the axial direction. One end of eachcompression spring88 could reside within a complementary shapedhole94 within theflange104 so that a portion of thecompression spring88 extends into the firstannular gap73 with sufficient length to contact thefirst end53 along theceramic runner52. Thecompression spring88 could be mechanically fixed to thehole94 via an interference fit or freely movable within thehole94. The compression springs88 are preferred to be sufficiently long so that each is partially compressed when assembled between thecarrier91 andceramic runner52. Partial compression of thecompression spring88 maintains a biasingforce99 onto theceramic runner52 so that thesecond end54 of theceramic runner52 is biased toward and contacts the clampingring74. The biasingforce99 maintains contact between thesecond end54 of theceramic runner52 and the clampingring74 during operation of a turbine engine, thereby avoiding separation thereof because of thermally induced expansion and contraction ofceramic runner52 and other components within the engine. The biasingforce99 also resists rotational sliding motion between theceramic runner52 and clampingring74 at thesecond end54. The compression springs88 are partially compressed at or below ambient conditions so as to allow for further compression of the compression springs88 during operation of a turbine engine. This feature allows the compression springs88 to expand and contract with expansion and contraction of theceramic runner52 as theceramic runner52 and other components heat and cool.
• In other embodiments, the spring mechanism could be a singleannular spring58, as represented inFIG. 8d. Exemplaryannular springs58 include a wave spring or a compression spring or the like which circumscribe theshaft57 within the firstannular gap73 between thefirst end53 of theceramic runner52 andfirst shoulder92 along thecarrier91. The length of theannular spring58 in its uncompressed state requires theannular spring58 to be partially compressed when assembled between theceramic runner52 andcarrier91. Theannular spring58 is compressed by contact with thefirst shoulder92 at one side of theannular spring58 and thefirst end53 at another side of theannular spring58. In its partially compressed state, theannular spring58 communicates a biasingforce99 axially onto theceramic runner52 thereby pressing theceramic runner52 onto the clampingring74. The biasingforce99 is preferred to maintain contact between thesecond end54 of theceramic runner52 and the clampingring74 during operation of a turbine engine, thereby avoiding separation between theceramic runner52 and clampingring74 which could occur because of thermally induced expansion and contraction of components within the engine. The biasingforce99 also resists rotational sliding motion between theceramic runner52 and the clampingring74 at thesecond end54. Theannular spring58 is partially compressed at or below ambient conditions so as to allow for further compression of theannular spring58 during operation of a turbine engine. This feature allows theannular spring58 to expand and contract with axial expansion and contraction of theceramic runner52 as theceramic runner52 and other components heat and cool.
• In other embodiments, thefirst end53 could directly contact thefirst shoulder92 and the spring mechanism, either anannular spring58 or compression springs88, is disposed between thesecond end54 and clampingring74, as generally represented inFIG. 8e. The biasingforce99 is directed toward theflange104. The anti-rotation key89 is attached to theflange104 along thecarrier91 so as to extend toward theceramic runner52. A portion of the anti-rotation key89 resides within aslot78 along thefirst side53. The spring mechanisms could be attached to the clampingring74 as described inFIG. 8a. For example, eachcompression spring88 could partially reside within ahole94 so as to extend across the firstannular gap73 and contact thesecond end54.
• Referring again toFIG. 8a, the secondannular gap72 between theinner diameter61 of theceramic runner52 andouter diameter106 of thecarrier91 is shown with a pair of tolerance rings70,71. Although two tolerance rings70,71 are shown and described, it is understood that the secondannular gap72 could include one or more such rings. The tolerance rings70,71 are generally described as a ring-shaped element with corrugations along an inward face or an outward face and with agap87, the latter feature represented inFIG. 6c. Tolerance rings70,71 provide no sealing functionality. When attached between theinner diameter61 andouter diameter106 along thegap72, the tolerance rings70,71 conform to the bore and are self-retaining thereby resisting rotational slippage between theceramic runner52 andcarrier91. The tolerance rings70,71 could allow for axial slippage so as to avoid stresses within theceramic runner52. Exemplary tolerance rings70,71 are the BN Series devices sold by USA Tolerance Rings of Pennington, N.J. (United States). The tolerance rings70,71 maintain proper fit between theceramic runner52 andcarrier91 by expanding circumferentially to the radial clearance between theinner diameter61 andouter diameter106 by closing thegap87. This functionality avoids radial expansion of theceramic runner52 which could damage therunner52. Eachtolerance ring70,71 resides within anannular groove63,65, respectively. Theannular grooves63,65 could be disposed along theinner diameter61 of theceramic runner52 in an arrangement similar to that shown inFIG. 6aor along theouter diameter106 of thecarrier91 as shown inFIG. 8a. The depth of eachannular groove63,65 should allow assembly of theceramic runner52 onto thecarrier91 and proper placement of the tolerance rings70,71 along thecarrier91 while ensuring sufficient contact between the tolerance rings70,71 and inner andouter diameters61,106 for proper function of the tolerance rings70,71. Theannular grooves63,65 should be at least as wide as the tolerance rings70,71, preferably providing a tolerance fit which allows eachtolerance ring70,71 to be secured within the respectiveannular groove63,65.
• Referring again toFIG. 8a, the secondannular gap72 between theinner diameter61 of theceramic runner52 andouter diameter106 of thecarrier91 is shown with a pair of sealing rings68,69. Sealing rings68,69 could include devices known within the art, examples including, but not limited to, multi-directional O-rings, unidirectional spring-energized seals, high-temperature metallic seal rings, or other comparable devices sold by the Parker Hannifin Corporation located in North Haven, Conn. (United States) or other suppliers. Other exemplary seals include those sold under the Trademark OMNISEAL® by Saint-Gobain Performance Plastics Corporation of Aurora, Ohio (United States). When assembled between theinner diameter61 andouter diameter106 along the secondannular gap72, the sealing rings68,69 conform to the bore thereby further resisting rotational slip between theceramic runner52 andcarrier91. The sealing rings68,69 could allow for axial slippage so as to avoid stresses within theceramic runner52. Each sealingring68,69 resides within anannular groove64,66, respectively. Theannular grooves64,66 are disposed along theinner diameter61 of theceramic runner52 in an arrangement similar to that shown inFIG. 6aor along theouter diameter106 of thecarrier91 as shown inFIG. 8a. The depth of eachannular groove64,66 should be sufficiently deep so as to allow assembly of theceramic runner52 onto thecarrier91 and proper placement of the sealing rings68,69 along thecarrier91 while ensuring sufficient contact between the sealing rings68,69 and inner andouter diameters61,106 for proper function of the sealing rings68,69. Thegrooves64,66 should be at least as wide as the sealing rings68,69, preferably with a tolerance fit allowing each sealingring68,69 to be secured within the respectiveannular groove64,66.
• The sealing rings68,69 are disposed about the tolerance rings70,71, as represented inFIG. 8a. The sealing rings68,69 are oriented along the secondannular gap72 so that the sealingdirection101 of the sealing rings68,69 avoids or at least minimizes oil and other contaminants within the higher and/or lower pressure sides81,82 from entering the secondannular gap72 and interacting with the tolerance rings70,71. This feature minimizes degradation to the performance of the tolerance rings70,71 caused by oil and other contaminants and further minimizes oil coking under theceramic runner52.
• The clampingring74 further includes at least oneanti-rotation key89. The anti-rotation key89 is attached or fixed to one side of the clampingring74 via techniques understood in the art so that a portion of the anti-rotation key89 extends toward theceramic runner52. The portion of the anti-rotation key89 extending from the clampingring74 could reside within aslot78 along theceramic runner52. Theslot78 could extend from theinner diameter61 of theceramic runner52 and partially traverse the thickness of theceramic runner52 in the direction of the outwardfacing sealing surface60, as represented inFIG. 8b. The anti-rotation key89 could include a circular head as shown inFIG. 8bor a substantially rectangular head. Theslot78 is dimensioned to avoid contact with the end and sides of the anti-rotation key89, seeFIGS. 8aand8b, respectively. The anti-rotation key89 could contact aside wall102, the latter shown inFIG. 8b, along theslot78 when theceramic runner52 rotates relative to the clampingring74. The degree of rotation before contact between the anti-rotation key89 andside wall102 is determined by the clearance therebetween, which is design dependent.
• Anannular seal ring49 is circumferentially disposed about the outwardfacing sealing surface60 of theceramic runner52. Theannular seal ring49 includes an inwardfacing sealing surface59 which interacts with the outwardfacing sealing surface60 to form the circumferential sealing of the present invention. Theannular seal ring49 is a ring-shaped element with or without segmentation. In some embodiments, the inwardfacing sealing surface59 could physically contact the outwardfacing sealing surface60 during rotation of theceramic runner52 andshaft57 to provide a contact seal. In other embodiments, the inwardfacing sealing surface59 and outward facing sealingsurface60 could be separated by a gap to form a non-contact seal. In yet other embodiments, the outwardfacing sealing surface60 could include hydrodynamic pockets which form a thin-film between inward and outward facing sealing surfaces59,60 during rotation of theceramic runner52.
• Theannular seal ring49 resides within aseal housing47 and is secured thereto via asupport ring50 and a retainingring51 or other like elements via methods and designs known within the art. Theannular seal ring49 is rotationally stationary with respect to theseal housing47. As such, theannular seal ring49 does not rotate with respect to theseal housing47. Theannular seal ring49 could move radially inward and outward to track radial excursions of theceramic runner52. Theseal housing47 is secured to ahousing48 comprising a turbine engine. Both sealhousing47 andhousing48 are shown in a generalized form for descriptive purposes only and are not intended to limit the scope of the claimed invention. Arrangement of theannular seal ring49, sealhousing47, andhousing48 about theceramic runner52 andshaft57 generally defines ahigher pressure side81 and alower pressure side82. Thehigher pressure side81 could define the air or gas side within a turbine engine. Thelower pressure side82 could define the bearing or oil side within a turbine engine.
• Referring again toFIG. 8a, the outwardfacing sealing surface60 along theceramic runner52 andannular surface107 of thecarrier91 are shown approximately radially aligned with theouter diameter100 of theshaft57. However, it is understood that outward facing sealingsurface60 andannular surface107 could extend above or be depressed below theouter diameter100 in other embodiments of the invention. In yet other embodiments, it is possible for the outwardfacing sealing surface60 andannular surface107 to move radially inward and outward with respect to theouter diameter100 during operation of a turbine engine.
• Referring now toFIG. 9a, thecircumferential seal46 is illustrated for descriptive purposes along an upper half of anexemplary shaft57 along a turbine engine rotatable about acenterline67. In this embodiment, aceramic runner52 is attached to acarrier91 to form acartridge90. Thecartridge90 facilitates assembly of components comprising thecircumferential seal46 prior to attachment to ashaft57. This approach simplifies assembly and repair of a turbine engine.
• Theouter diameter100 of theshaft57 is shown including arecess98. Therecess98 could include one or more regions along theshaft57 each having a diameter smaller than theouter diameter100. Theexemplary shaft57 has arecess98 which includes a single section to accommodate alocking ring75 and acarrier91, the latter supporting aceramic runner52 and aclamping ring74. The clampingring74 and lockingring75 are composed of materials suitable for use within a turbine engine. Materials should be wear, failure, and temperature resistant. Exemplary compositions include metals, preferably compositions of steel. The lockingring75 secures thecarrier91 with the various components described herein to theshaft57 about therecess98. It is understood that therecess98 could include one or more sections as well as other shapes and designs which facilitate attachment of elements required to provide circumferential sealing along ashaft57.
• The interface between theouter diameter100 of theshaft57 and theouter diameter62 of therecess98 defines afirst shoulder55. Therecess98 could include additional shoulders depending on the profile of therecess98, although such features are optional and design dependent. For example, therecess98 could include other shoulders each defined by a discontinuity where two outer diameters differ.
• Thecarrier91 is a ring-shaped element with aflange104 which extends perpendicular from one end anannular ring105. In some embodiments, a clearance fit is provided for assembly purposes between theouter diameter62 of theshaft57 andinner diameter85 of thecarrier91 so that thecarrier91 is slidable with respect to theshaft57. In other embodiments, an interference fit is provided between theouter diameter62 and theinner diameter85 and thecarrier91 is heated to open theinner diameter85 prior to sliding thecarrier91 onto theshaft57. Thecarrier91 is then cooled to fix thecarrier91 to theshaft57. Theflange104 should contact theshoulder55 in addition to theannular ring105 contacting the surface of theshaft57. Thecarrier91 is composed of materials suitable for use within a turbine engine. Materials should be wear, failure, and temperature resistant. Exemplary compositions include metals, preferably compositions of steel with a coefficient of thermal expansion comparable to that of theshaft57 so thatcarrier91 tracks the expansion and contraction of theshaft57.
• Thecarrier91 could likewise include one or more shoulders along theannular ring105. The interface between theannular surface107 along thecarrier91 and theouter diameter106 of thecarrier91 defines afirst shoulder92. Thecarrier91 could also include a first segment with anouter diameter106 and a second segment with anouter diameter86. Theouter diameter106 could be larger than the otherouter diameter86 so that asecond shoulder103 is provided at the discontinuity between the two outer surfaces. A clearance fit could be provided between theouter diameter86 of thecarrier91 andinner diameter83 along the clampingring74 so that the clampingring74 is slidable with respect to thecarrier91. Thecarrier91 and clampingring74 are secured to theshaft57 via the lockingring75. The lockingring75 contacts both the clampingring74 and theend93 of thecarrier91 as illustrate inFIG. 9a. The lockingring75 includes threads along itsinner diameter84 which engage a complementary thread arrangement along theouter diameter80 of theshaft57. The force applied by the lockingring75 onto thecarrier91 and clampingring74 should be sufficient to prevent relative motion with respect to theshaft57.
• Theceramic runner52 is a cylindrically-shaped or sleeve-shaped element which is slid onto theshaft57 during assembly so as to circumscribe thecarrier91. Theceramic runner52 is composed of a ceramic composition suitable for use within a turbine engine. In preferred embodiments, the ceramic composition should be wear, failure, and temperature resistant. Exemplary, non-limiting compositions include silicon nitride and silicon carbide.
• Theceramic runner52 has aninner diameter61 which is larger than theouter diameter106 of thecarrier91 resulting in a secondannular gap72 which avoids direct contact between theceramic runner52 andcarrier91. The distance between afirst end53 and asecond end54 of theceramic runner52 is less than the axial distance between thefirst shoulder92 andsecond shoulder103. Thefirst end53 is positioned adjacent to thefirst shoulder92 so that a firstannular gap73 separates thefirst end53 from thefirst shoulder92. The axial length of the firstannular gap73 is sized to accommodate a spring mechanism. The spring mechanism provides no sealing functionality. Although spring mechanisms are described herein, it is understood that such mechanisms could include other non-sealing devices which at least resist compression and are resilient. Thesecond end54 directly contacts the clampingring74 so that thesecond end54 is generally aligned with thesecond shoulder103.
• In some embodiments, the spring mechanism could include a plurality of compression springs88 as represented inFIG. 9aand generally described inFIGS. 7band7c. Eachcompression spring88 is axially aligned along the direction of theshaft57. The compression springs88 are further separately disposed about theshaft57 along theflange104 of thecarrier91, as generally shown inFIG. 8c, so as to communicate a biasingforce99 symmetrically about theceramic runner52 in the axial direction. One end of eachcompression spring88 could reside within a complementary shapedhole94 within theflange104 so that a portion of thecompression spring88 extends into the firstannular gap73 with sufficient length to contact thefirst end53 along theceramic runner52. Thecompression spring88 could be mechanically fixed to thehole94 via an interference fit or freely movable within thehole94. The compression springs88 are preferred to be sufficiently long so that each is partially compressed when assembled between thecarrier91 andceramic runner52. Partial compression of thecompression spring88 maintains a biasingforce99 onto theceramic runner52 so that thesecond end54 of theceramic runner52 is biased toward and contacts the clampingring74. The biasingforce99 maintains contact between thesecond end54 of theceramic runner52 and the clampingring74 during operation of a turbine engine, thereby avoiding separation thereof because of thermally induced expansion and contraction ofceramic runner52 and other components within the engine. The biasingforce99 is also resists rotational sliding between theceramic runner52 and clampingring74 at thesecond end54. The compression springs88 are partially compressed at or below ambient conditions so as to allow for further compression of the compression springs88 during operation of a turbine engine. This feature allows the compression springs88 to expand and contract with expansion and contraction of theceramic runner52 as theceramic runner52 and other components heat and cool.
• In other embodiments, the spring mechanism could be a singleannular spring58, as represented inFIG. 8d. Exemplaryannular springs58 include a wave spring or a compression spring or the like which circumscribe theshaft57 within the firstannular gap73 between thefirst end53 of theceramic runner52 andfirst shoulder92 along thecarrier91. The length of theannular spring58 in its uncompressed state requires theannular spring58 to be partially compressed when assembled between theceramic runner52 andcarrier91. Theannular spring58 is compressed by contact with thefirst shoulder92 at one side of theannular spring58 and thefirst end53 at another side of theannular spring58. In its partially compressed state, theannular spring58 communicates a biasingforce99 axially onto theceramic runner52 thereby pressing theceramic runner52 onto the clampingring74. The biasingforce99 is preferred to maintain contact between thesecond end54 of theceramic runner52 and the clampingring74 during operation of a turbine engine, thereby avoiding separation between theceramic runner52 and clampingring74 which could occur because of thermally induced expansion and contraction of components within the engine. The biasingforce99 also resists rotational sliding motion between theceramic runner52 and the clampingring74 at thesecond end54. Theannular spring58 is partially compressed at or below ambient conditions so as to allow for further compression of theannular spring58 during operation of a turbine engine. This feature allows theannular spring58 to expand and contract with axial expansion and contraction of theceramic runner52 as theceramic runner52 and other components heat and cool.
• In other embodiments, thefirst end53 could directly contact thefirst shoulder92 and the spring mechanism, either theannular spring58 or the compression springs88, is disposed between thesecond end54 and clampingring74, as shown inFIG. 9e. The biasingforce99 is directed toward theflange104. The spring mechanisms could be attached to the clampingring74 via in a similar manner as the attachment to theflange104 as described inFIG. 9a. The firstannular gap73 is now disposed between the clampingring74 andsecond end54.
• Referring again toFIG. 9a, the secondannular gap72 between theinner diameter61 of theceramic runner52 andouter diameter106 of thecarrier91 is shown with atolerance ring70. Although onetolerance ring70 is shown and described, it is understood that the secondannular gap72 could include one or more such rings. Thetolerance ring70 is generally described as a ring-shaped element with corrugations along an inward face or an outward face and with agap87, the latter feature represented inFIG. 6c. Thetolerance ring70 provides no sealing functionality. When attached between theinner diameter61 andouter diameter106 along thegap72, thetolerance ring70 conforms to the bore and is self-retaining thereby resisting rotational slip between theceramic runner52 andcarrier91. Thetolerance ring70 could allow for axial slippage so as to avoid stresses within theceramic runner52. Anexemplary tolerance ring70 is the BN Series devices sold by USA Tolerance Rings of Pennington, N.J. (United States). Thetolerance ring70 maintains proper fit between theceramic runner52 andcarrier91 by expanding circumferentially to the radial clearance between theinner diameter61 andouter diameter106 by closing thegap87. This functionality avoids radial expansion of theceramic runner52, which could damage therunner52. Thetolerance ring70 resides within anannular groove63. Theannular groove63 could be disposed along theinner diameter61 of theceramic runner52 in an arrangement similar to that shown inFIG. 6aor along theouter diameter106 of thecarrier91 as shown inFIG. 9a. The depth of theannular groove63 should allow assembly of theceramic runner52 onto thecarrier91 and proper placement of thetolerance ring70 along thecarrier91 while ensuring sufficient contact between thetolerance ring70 and inner andouter diameters61,106 for proper function of thetolerance ring70. Theannular groove63 should be at least as wide as thetolerance ring70, preferably providing a tolerance fit allowing thetolerance ring70 to be secured within theannular groove63.
• Referring again toFIG. 9a, the secondannular gap72 between theinner diameter61 of theceramic runner52 andouter diameter106 of thecarrier91 is shown with a sealingring68. The clampingring74 also includes a sealingring69 disposed along the vertical surface at the interface with theceramic runner52. In other embodiments, theseal ring69 could be disposed within anannular groove66 between thecarrier91 and theceramic runner52 along the secondannular gap72 further between the clampingring74 andanti-rotation screw96, as shown inFIG. 9d. Sealing rings68,69 could include devices known within the art, examples including, but not limited to, multi-directional O-rings, unidirectional spring-energized seals, high-temperature metallic seal rings, or other comparable devices sold by the Parker Hannifin Corporation located in North Haven, Conn. (United States) or other suppliers. Other exemplary seals include those sold under the Trademark OMNISEAL® by Saint-Gobain Performance Plastics Corporation of Aurora, Ohio (United States). When assembled between theinner diameter61 andouter diameter106 along the secondannular gap72, the sealingring68 conforms to the bore thereby further resisting rotational slip between theceramic runner52 andcarrier91. The sealingring68 could allow for axial slippage so as to avoid stresses within theceramic runner52. The sealingring69 conforms to the ring-shaped surfaces to further resist rotational slip when assembled between the clampingring74 and theceramic runner52. Each sealingring68,69 resides within anannular groove64,66, respectively. Theannular groove64 could be disposed along theinner diameter61 of theceramic runner52 in an arrangement similar to that shown inFIG. 6aor along theouter diameter106 of thecarrier91 as shown inFIG. 9a. The depth of eachannular groove64,66 should be sufficiently deep so as to allow assembly of theceramic runner52 onto thecarrier91 and proper placement of the sealing rings68,69 along thecarrier91 while ensuring sufficient contact between the sealingring68 and inner andouter diameters61,106, as well as the sealingring69 and theceramic runner52 and clampingring74, for proper function of the sealing rings68,69. Thegrooves64,66 should be at least as wide as the sealing rings68,69, preferably with a tolerance fit allowing each sealingring68,69 to be secured within the respectiveannular groove64,66.
• The sealing rings68,69 are disposed about thetolerance ring70, as represented inFIG. 9a. The sealing rings68,69 are oriented so that the sealingdirection101 avoids or at least minimizes oil and other contaminants within the higher and/or lower pressure sides81,82 from entering the secondannular gap72 and interacting with thetolerance ring70. This feature minimizes degradation to the performance of the tolerance rings70 caused by oil and other contaminants and further minimizes oil coking under theceramic runner52.
• Referring again toFIG. 9a, thecarrier91 further includes at least oneanti-rotation screw96. Theanti-rotation screw96 is attached or fixed to a threadedhole95 along thecarrier91, as represented inFIG. 9b, via techniques understood in the art so that a portion of theanti-rotation screw96 extends toward theceramic runner52. The end of theanti-rotation screw96 extending from thecarrier91 could reside within a hole orslot97 along theceramic runner52. The hole orslot97 could extend from theinner diameter61 of theceramic runner52 and partially traverse the thickness of theceramic runner52 in the direction of the outwardfacing sealing surface60. The hole orslot97 is dimensioned to avoid contact with the end and side of theanti-rotation screw96, seeFIGS. 9aand9c, respectively. Theanti-rotation screw96 could contact a side of the hole orslot97 when theceramic runner52 rotates relative to thecarrier91. The degree of rotation before contact between theanti-rotation screw96 and side of the threadedhole95 is determined by the clearance therebetween which is design dependent.
• Anannular seal ring49 is circumferentially disposed about the outwardfacing sealing surface60 of theceramic runner52. Theannular seal ring49 includes an inwardfacing sealing surface59 which interacts with the outwardfacing sealing surface60 to form the circumferential sealing of the present invention. Theannular seal ring49 is a ring-shaped element with or without segmentation. In some embodiments, the inwardfacing sealing surface59 could physically contact the outwardfacing sealing surface60 during rotation of theceramic runner52 andshaft57 to provide a contact seal. In other embodiments, the inwardfacing sealing surface59 and outward facing sealingsurface60 could be separated by a gap to form a non-contact seal. In yet other embodiments, the outwardfacing sealing surface60 could include hydrodynamic pockets which form a thin-film between inward and outward facing sealing surfaces59,60 during rotation of theceramic runner52.
• Theannular seal ring49 resides within aseal housing47 and is secured thereto via asupport ring50 and a retainingring51 or other like elements via methods and designs known within the art. Theannular seal ring49 is rotationally stationary with respect to theseal housing47. As such, theannular seal ring49 does not rotate with respect to theseal housing47. Theannular seal ring49 could move radially inward and outward to track radial excursions of theceramic runner52. Theseal housing47 is secured to ahousing48 comprising a turbine engine. Both sealhousing47 andhousing48 are shown in a generalized form for descriptive purposes only and are not intended to limit the scope of the claimed invention. Arrangement of theannular seal ring49, sealhousing47, andhousing48 about theceramic runner52 andshaft57 generally defines ahigher pressure side81 and alower pressure side82. Thehigher pressure side81 could define the air or gas side within a turbine engine. Thelower pressure side82 could define the bearing or oil side within a turbine engine.
• Referring again toFIG. 9a, the outwardfacing sealing surface60 along theceramic runner52 andannular surface107 of thecarrier91 are shown approximately radially aligned with theouter diameter100 of theshaft57. However, it is understood that outward facing sealingsurface60 andannular surface107 could extend above or be depressed below theouter diameter100 in other embodiments of the invention. In yet other embodiments, it is possible for the outwardfacing sealing surface60 andannular surface107 to move radially inward and outward with respect to theouter diameter100 during operation of a turbine engine.
• The invention is applicable for use within a variety of applications wherein sealing is required about a rotatable element. One specific non-limiting example is a turbine engine including a circumferential seal formed between a stationary annular seal and a rotatable runner.
• The description above indicates that a great degree of flexibility is offered in terms of the present invention. Although various embodiments have been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.

Claims (54)

What is claimed is:

1. A circumferential seal comprising:

(a) a ceramic runner circumscribed about a recess along a shaft, said recess bounded by a shoulder and a clamping ring, a first annular gap disposed between a first end of said ceramic runner and said shoulder, a second end of said ceramic runner directly contacts said clamping ring, an anti-rotation pin attached to said clamping ring and extends into a slot along said ceramic runner, at least one non-sealing spring mechanism disposed between and directly contacts said shoulder and said first end along said first annular gap, said at least one non-sealing spring mechanism applies a biasing force onto said ceramic runner toward said clamping ring;

(b) an annular seal ring circumscribed about said ceramic runner and disposed within a seal housing so that said annular seal ring is rotationally stationary;

(c) at least one tolerance ring directly contacts said ceramic runner and said shaft along a second annular gap between said ceramic runner and said shaft, said ceramic runner fixed to said shaft via said at least one tolerance ring, said anti-rotation pin, and said at least one non-sealing spring mechanism so that said ceramic runner rotates with said shaft, said at least one non-sealing spring mechanism expands and contracts in response to expansion and contraction of said ceramic runner; and

(d) a pair of sealing rings directly contacts said ceramic runner and said shaft between said pair of sealing rings.

2. The circumferential seal ofclaim 1, wherein said at least one non-sealing spring mechanism is a wave spring.

3. The circumferential seal ofclaim 1, wherein said at least one non-sealing spring mechanism is a compression spring.

4. The circumferential seal ofclaim 1, wherein said at least one non-sealing spring mechanism is a plurality of compression springs separately disposed about said first annular gap, each said compression spring separately attached to said shoulder.

5. The circumferential seal ofclaim 1, wherein each said tolerance ring and each said sealing ring separately disposed within an equal number of annular grooves along said ceramic runner.

6. The circumferential seal ofclaim 1, wherein each said tolerance ring and each said sealing ring separately disposed within an equal number of annular grooves along said shaft.

7. The circumferential seal ofclaim 1, wherein said annular seal ring forms a contact seal about said ceramic runner.

8. The circumferential seal ofclaim 1, wherein said annular seal ring forms a non-contact seal about said ceramic runner.

9. The circumferential seal ofclaim 1, wherein at least one said sealing ring is an O-ring, a spring-energized seal, or a high-temperature metallic seal ring.

10. A circumferential seal comprising:

(a) a ceramic runner circumscribed about a recess along a shaft, said recess bounded by a shoulder and a clamping ring, a first annular gap disposed between a second end of said ceramic runner and said clamping ring, a first end of said ceramic runner directly contacts said shoulder along said shaft, an anti-rotation pin attached to said shoulder and extends into a slot along said ceramic runner, at least one non-sealing spring mechanism disposed between and directly contacts said clamping ring and said second end along said first annular gap, said at least one non-sealing spring mechanism applies a biasing force onto said ceramic runner toward said shoulder;

(b) an annular seal ring circumscribed about said ceramic runner and disposed within a seal housing so that said annular seal ring is rotationally stationary;

(c) at least one tolerance ring directly contacts said ceramic runner and said shaft along a second annular gap between said ceramic runner and said shaft, said ceramic runner fixed to said shaft via said at least one tolerance ring, said anti-rotation pin, and said at least one non-sealing spring mechanism so that said ceramic runner rotates with said shaft, said at least one non-sealing spring mechanism expands and contracts in response to expansion and contraction of said ceramic runner; and

(d) a pair of sealing rings directly contacts said ceramic runner and said shaft along said second annular gap, said at least one tolerance ring disposed between said pair of sealing rings.

11. The circumferential seal ofclaim 10, wherein said at least one non-sealing spring mechanism is a wave spring.

12. The circumferential seal ofclaim 10, wherein said at least one non-sealing spring mechanism is a compression spring.

13. The circumferential seal ofclaim 10, wherein said at least one non-sealing spring mechanism is a plurality of compression springs separately disposed about said first annular gap, each said compression spring separately attached to said clamping ring.

14. The circumferential seal ofclaim 10, wherein each said tolerance ring and each said sealing ring separately disposed within an equal number of annular grooves along said ceramic runner.

15. The circumferential seal ofclaim 10, wherein each said tolerance ring and each said sealing ring separately disposed within an equal number of annular grooves along said shaft.

16. The circumferential seal ofclaim 10, wherein said annular seal ring forms a contact seal about said ceramic runner.

17. The circumferential seal ofclaim 10, wherein said annular seal ring forms a non-contact seal about said ceramic runner.

18. The circumferential seal ofclaim 10, wherein at least one said sealing ring is an O-ring, a spring-energized seal, or a high-temperature metallic seal ring.

19. A circumferential seal comprising:

(a) a carrier disposed about and directly contacts a shaft within a recess along said shaft, said carrier rotatable with said shaft, said carrier having a shoulder at one end;

(b) a ceramic runner circumscribed about said carrier, said ceramic runner disposed between said shoulder and a clamping ring, a first annular gap disposed between a first end of said ceramic runner and said shoulder, a second end of said ceramic runner directly contacts said clamping ring, an anti-rotation key attached to said clamping ring and extends into a slot along said ceramic runner, at least one non-sealing spring mechanism directly contacts said shoulder and said first end along said first annular gap, said at least one non-sealing spring mechanism applies a biasing force onto said ceramic runner toward said clamping ring;

(c) an annular seal ring circumscribed about said ceramic runner and disposed within a seal housing so that said annular seal ring is rotationally stationary;

(d) at least one tolerance ring directly contacts said ceramic runner and said carrier along a second annular gap between said ceramic runner and said carrier, said ceramic runner fixed to said carrier via said at least one tolerance ring, said anti-rotation key, and said at least one non-sealing spring mechanism so that said ceramic runner rotates with said carrier, said at least one non-sealing spring mechanism expands and contracts in response to expansion and contraction of said ceramic runner; and

(e) a pair of sealing rings directly contacts said ceramic runner and said carrier along said second annular gap, said at least one tolerance ring disposed between said pair of sealing rings.

20. The circumferential seal ofclaim 19, wherein said at least one non-sealing spring mechanism is a wave spring.

21. The circumferential seal ofclaim 19, wherein said at least one non-sealing spring mechanism is a compression spring.

22. The circumferential seal ofclaim 19, wherein said at least one non-sealing spring mechanism is a plurality of compression springs separately disposed about said first annular gap, each said compression spring separately attached to said shoulder.

23. The circumferential seal ofclaim 19, wherein each said tolerance ring and each said sealing ring separately disposed within an equal number of annular grooves along said carrier.

24. The circumferential seal ofclaim 19, wherein each said tolerance ring and each said sealing ring separately disposed within an equal number of annular grooves along said ceramic runner.

25. The circumferential seal ofclaim 19, wherein said annular seal ring forms a contact seal about said ceramic runner.

26. The circumferential seal ofclaim 19, wherein said annular seal ring forms a non-contact seal about said ceramic runner.

27. The circumferential seal ofclaim 19, wherein at least one said sealing ring is an O-ring, a spring-energized seal, or a high-temperature metallic seal ring.

28. A circumferential seal comprising:

(a) a carrier disposed about and directly contacts a shaft within a recess along said shaft, said carrier rotatable with said shaft, said carrier having a shoulder at one end;

(b) a ceramic runner circumscribed about said carrier, said ceramic runner disposed between said shoulder and a clamping ring, a first annular gap disposed between a second end of said ceramic runner and said clamping ring, a first end of said ceramic runner directly contacts said shoulder, an anti-rotation key attached to said shoulder and extends into a slot along said ceramic runner, at least one non-sealing spring mechanism directly contacts said clamping ring and said second end along said first annular gap, said at least one non-sealing spring mechanism applies a biasing force onto said ceramic runner toward said shoulder;

(c) an annular seal ring circumscribed about said ceramic runner and disposed within a seal housing so that said annular seal ring is rotationally stationary;

(d) at least one tolerance ring directly contacts said ceramic runner and said carrier along a second annular gap between said ceramic runner and said carrier, said ceramic runner fixed to said carrier via said at least one tolerance ring, said anti-rotation key, and said at least one non-sealing spring mechanism so that said ceramic runner rotates with said carrier, said at least one non-sealing spring mechanism expands and contracts in response to expansion and contraction of said ceramic runner; and

(e) a pair of sealing rings directly contacts said ceramic runner and said carrier along said second annular gap, said at least one tolerance ring disposed between said pair of sealing rings.

29. The circumferential seal ofclaim 28, wherein said at least one non-sealing spring mechanism is a wave spring.

30. The circumferential seal ofclaim 28, wherein said at least one non-sealing spring mechanism is a compression spring.

31. The circumferential seal ofclaim 28, wherein said at least one non-sealing spring mechanism is a plurality of compression springs separately disposed about said first annular gap, each said compression spring separately attached to said clamping ring.

32. The circumferential seal ofclaim 28, wherein each said tolerance ring and each said sealing ring separately disposed within an equal number of annular grooves along said carrier.

33. The circumferential seal ofclaim 28, wherein each said tolerance ring and each said sealing ring separately disposed within an equal number of annular grooves along said ceramic runner.

34. The circumferential seal ofclaim 28, wherein said annular seal ring forms a contact seal about said ceramic runner.

35. The circumferential seal ofclaim 28, wherein said annular seal ring forms a non-contact seal about said ceramic runner.

36. The circumferential seal ofclaim 28, wherein at least one said sealing ring is an O-ring, a spring-energized seal, or a high-temperature metallic seal ring.

37. A circumferential seal comprising:

(a) a carrier disposed about and directly contacts a shaft within a recess along said shaft, said carrier rotatable with said shaft, said carrier having a shoulder at one end;

(b) a ceramic runner circumscribed about said carrier, said ceramic runner disposed between said shoulder and a clamping ring, a first annular gap disposed between a first end of said ceramic runner and said shoulder, a second end of said ceramic runner directly contacts said clamping ring, an anti-rotation screw attached to said carrier and extends into a hole along said ceramic runner, at least one non-sealing spring mechanism directly contacts said shoulder and said first end along said first annular gap, said at least one non-sealing spring mechanism applies a biasing force onto said ceramic runner toward said clamping ring;

(c) an annular seal ring circumscribed about said ceramic runner and disposed within a seal housing so that said annular seal ring is rotationally stationary;

(d) at least one tolerance ring directly contacts said ceramic runner and said carrier along a second annular gap between said ceramic runner and said carrier, said ceramic runner fixed to said carrier via said at least one tolerance ring, said anti-rotation screw, and said at least one non-sealing spring mechanism so that said ceramic runner is rotatable with said carrier, said at least one non-sealing spring mechanism expands and contracts in response to expansion and contraction of said ceramic runner; and

(e) a pair of sealing rings, at least one said sealing ring directly contacts said ceramic runner and said carrier along said second annular gap, said at least one tolerance ring and said anti-rotation screw disposed between said pair of sealing rings.

38. The circumferential seal ofclaim 37, wherein said at least one non-sealing spring mechanism is a wave spring.

39. The circumferential seal ofclaim 37, wherein said at least one non-sealing spring mechanism is a compression spring.

40. The circumferential seal ofclaim 37, wherein said at least one non-sealing spring mechanism is a plurality of compression springs separately disposed about said first annular gap, each said compression spring separately attached to said shoulder.

41. The circumferential seal ofclaim 37, wherein each said tolerance ring and one said sealing ring separately disposed within an equal number of annular grooves along said carrier and another said sealing ring disposed within another said annular groove along said clamping ring.

42. The circumferential seal ofclaim 37, wherein each said tolerance ring and one said sealing ring separately disposed within an equal number of annular grooves along said ceramic runner and another said sealing ring disposed within another said annular groove along said clamping ring.

43. The circumferential seal ofclaim 37, wherein said annular seal ring forms a contact seal about said ceramic runner.

44. The circumferential seal ofclaim 37, wherein said annular seal ring forms a non-contact seal about said ceramic runner.

45. The circumferential seal ofclaim 37, wherein at least one said sealing ring is an O-ring, a spring-energized seal, or a high-temperature metallic seal ring.

46. A circumferential seal comprising:

(a) a carrier disposed about and directly contacts a shaft within a recess along said shaft, said carrier rotatable with said shaft, said carrier having a shoulder at one end;

(b) a ceramic runner circumscribed about said carrier, said ceramic runner disposed between said shoulder and a clamping ring, a first annular gap disposed between a second end of said ceramic runner and said clamping ring, a first end of said ceramic runner directly contacts said shoulder, an anti-rotation screw attached to said carrier and extends into a hole along said ceramic runner, at least one non-sealing spring mechanism directly contacts said clamping ring and said second end along said first annular gap, said at least one non-sealing spring mechanism applies a biasing force onto said ceramic runner toward said shoulder;

(c) an annular seal ring circumscribed about said ceramic runner and disposed within a seal housing so that said annular seal ring is rotationally stationary;

(d) at least one tolerance ring directly contacts said ceramic runner and said carrier along a second annular gap between said ceramic runner and said carrier, said ceramic runner fixed to said carrier via said at least one tolerance ring, said anti-rotation screw, and said at least one non-sealing spring mechanism so that said ceramic runner is rotatable with said carrier, said at least one non-sealing spring mechanism expands and contracts in response to expansion and contraction of said ceramic runner; and

(e) a pair of sealing rings, at least on said sealing ring directly contacts said ceramic runner and said carrier along said second annular gap, said at least one tolerance ring and said anti-rotation screw disposed between said pair of sealing rings.

47. The circumferential seal ofclaim 46, wherein said at least one non-sealing spring mechanism is a wave spring.

48. The circumferential seal ofclaim 46, wherein said at least one non-sealing spring mechanism is a compression spring.

49. The circumferential seal ofclaim 46, wherein said at least one non-sealing spring mechanism is a plurality of compression springs separately disposed about said first annular gap, each said compression spring separately attached to said clamping ring.

50. The circumferential seal ofclaim 46, wherein each said tolerance ring and one said sealing ring separately disposed within an equal number of annular grooves along said carrier and another said sealing ring disposed within another said annular groove along said clamping ring.

51. The circumferential seal ofclaim 46, wherein each said tolerance ring and one said sealing ring separately disposed within an equal number of annular grooves along said ceramic runner and another said sealing ring disposed within another said annular groove along said clamping ring.

52. The circumferential seal ofclaim 46, wherein said annular seal ring forms a contact seal about said ceramic runner.

53. The circumferential seal ofclaim 46, wherein said annular seal ring forms a non-contact seal about said ceramic runner.

54. The circumferential seal ofclaim 46, wherein at least one said sealing ring is an O-ring, a spring-energized seal, or a high-temperature metallic seal ring.

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