Interposable Seal Assembly for Sealing Between Shafts

DESCRIPTION

1. Technical Field

The disclosure generally relates to sealing and more particularly is concerned, for example, with intershaft-type sealing between an inner shaft and an outer shaft for separating a first side and a second side wherein the seal assembly includes a sealing ring secured to an annular member adapted so that the sealing ring maintains a face seal adjacent to one of the shafts.

2. Background Art

Intershaft sealing is suitable for use within turbine engines and other applications that require sealing between a rotatable runner and a non-rotatable frame, or between a rotating shaft and a non-rotating shaft, or between a pair of co-rotating shafts, or between a pair of counter-rotating shafts. Sealing assemblies for such applications are described by Vasagar in U.S. Patent No. 8,205,891 entitled Intershaft Seal Assembly. In one example, a sealing ring sealingly contacts a circumferential surface of a shaft. In another example, a sealing ring circumferentially contacts at least one end ring so as to maintain a controlled-leak clearance adjacent to a circumferential surface of a shaft. In these examples, circumferential sealing is formed by either contacting or non-contacting means between a circumferential surface of the sealing ring adjacent to the circumferential surface of the shaft, whereby the sealing ring presents a barrier between fluid at one side of the sealing ring and fluid at another side of the sealing ring.

Intershaft sealing assemblies capable of circumferential sealing often include design-inherent deficiencies. In one example, a circumferential sealing ring of an intershaft seal may include a gap which allows the sealing ring to expand and contract. This gap, however, permits some fluid at a higher-pressure side of the sealing ring to traverse the sealing ring so as to enter a lower-pressure side of the sealing ring. In another example, a circumferential sealing ring is separated from a shaft by a clearance which minimizes contact therebetween. This clearance, however, permits some fluid at a higher-pressure side to pass around the sealing ring so as to enter a lower-pressure side. In yet another example, continuous or intermittent contact between an inside corner along a circumferential sealing ring of an intershaft seal and an end ring may mechanically and/or thermally stress the sealing ring so as to weaken or compromise the ring. These and other circumferential-sealing designs are therefore susceptible to reduced sealing function, reduced sealing life, and greater friction- induced wearing and heating. The engines and other applications within which these and other circumferential-sealing designs are used may experience compromised performance or function within the higher-pressure side and/or the lower-pressure side about the sealing ring.

These and other design-inherent deficiencies of intershaft sealing assemblies are amplified by improvements to turbine engines and other applications implemented via higher-rotational speeds by the shaft(s). The knock-on effects are higher centrifugal forces which increase with the square of rotational speed and correspondingly greater wearing, heating, and stressing of a sealing ring.

The operational life and performance of a sealing ring are optimized by minimizing wear, heat, and stress experienced by a sealing ring; therefore, improved performance with respect to power, efficiency, or another metric specific to a turbine engine or other application is often detrimental to the seals therein, and particularly circumferential seals. The end results may include more frequent maintenance and higher operating costs over the lifecycle of the turbine engine or other application within which a seal is employed.

Therefore, it is understood that advances within the turbine engine and other arts continue to drive the need for more durable, resilient, and reliable seal assemblies interposable between structures wherein at least one of such structures rotates. Accordingly, these interposable seal assemblies should optimize sealing function and seal life, mitigate seal wear, heating and stresses, and/or minimize impairment within the compartments separated thereby.

Accordingly, what is required is an interposable seal with an adaptive face seal applicable to sealing between a pair of shafts which avoids at least one of the design- inherent deficiencies of intershaft seals that rely on circumferential sealing.

3. Summary of the Disclosure

An object of the disclosure is an interposable seal with an adaptive face seal applicable to sealing between a pair of shafts which avoids at least one of the design- inherent deficiencies of intershaft seals that rely on circumferential sealing.

In accordance with embodiments of the interposable seal assembly for sealing between a pair of shafts to separate a first side and a second side, the assembly includes a first ring, a second ring, an annular member, a sealing ring, and an annular pocket. The annular member is radially disposed between and secured to the first ring and the second ring. The sealing ring is secured to and movable with the second ring. The annular pocket is disposed between a pair of end rings. The first ring is secured to one of the shafts. The end rings are secured to another of the shafts with the sealing ring disposed between the end rings. Each end ring has a sealing surface within the annular pocket. The sealing ring is biased toward one of the sealing surfaces so as to form a face seal. The face seal is disposed between a face of the sealing ring and the sealing surface. The annular member is adapted to maintain the face seal when one shaft moves relative to another shaft.

In accordance with other embodiments, one of the shafts is an inner shaft and another of the shafts is an outer shaft. The annular member has a pair of ends. The first ring is secured to one of the ends within an opening of the annular member. The first ring is secured along an outer surface of the inner shaft. The end rings are secured along an inner surface of the outer shaft. The second ring is secured about another of the ends. The second ring is movable between the end rings adjacent to the outer shaft.

In accordance with other embodiments, one of the shafts is an outer shaft and another of the shafts is an inner shaft. The annular member has a pair of ends. The first ring is secured about one of the ends. The first ring is secured along an inner surface of the outer shaft. The end rings are secured along an outer surface of the inner shaft. The second ring is secured to another of the ends within an opening of the annular member. The second ring is movable between the end rings adjacent to the inner shaft.

In accordance with other embodiments, a spacer ring is disposed between the end rings with a gap radially disposed between the spacer ring and the sealing ring.

In accordance with other embodiments, one of the ends is secured at a joint to a surface of one of the first ring or the second ring.

In accordance with other embodiments, one of the ends is secured within a pocket along a surface of one of the first ring or the second ring.

In accordance with other embodiments, one of the ends is rotatably secured to one of the first ring or the second ring. In accordance with other embodiments, one of the ends includes a shaped flange rotatable within a shaped pocket along a surface of one of the first ring or the second ring.

In accordance with other embodiments, the sealing ring is wider than the second ring.

In accordance with other embodiments, the sealing ring includes a first portion and a second portion wherein the first portion is wider than each of the second portion and the second ring.

In accordance with other embodiments, the annular member is resilient.

In accordance with other embodiments, the annular member is deformable.

In accordance with other embodiments, the annular member is non-planar.

In accordance with other embodiments, the annular member has a corrugated cross section.

In accordance with other embodiments, the annular member is planar.

In accordance with other embodiments, the interposable seal assembly further includes a second annular member radially disposed between and secured to the first ring and the second ring.

In accordance with other embodiments, two interposable seal assemblies are disposed between the first side and the second side.

In accordance with other embodiments, abutting end rings form a single end ring.

In accordance with other embodiments, the face seals are adjacently disposed.

In accordance with other embodiments, the sealing ring and the end rings permit for bi-directional sealing.

In its simplest form, the interposable seal includes a first ring, an annular member, a second ring, and a sealing ring. One end of the annular member is secured to the first ring. Another end of the annular member is secured to the second ring. This arrangement places the annular member between the rings so that the annular member is radially oriented between the rings. The second ring is secured to the sealing ring so that the second ring is disposed between the sealing ring and the annular member. The shape and/or material(s) of the annular member may permit for either a springlike motion when the sealing ring is contacted or a non-springlike motion when the sealing ring is contacted. The annular member is a generally, disk-shaped element with an opening; although, other shapes are possible. One ring is secured to the annular member within the opening. Another ring is secured about the outer perimeter of the annular member. In preferred embodiments, the material(s) and/or the cross section of the annular member should permit either the first ring to move toward or relative to the second ring or the second ring to move toward or relative to the first ring when at least one of the rings is axially or radially contacted or moved either directly or indirectly by a shaft, a component attached to a shaft, or a component adjacent to the interposable seal.

The interposable seal may be arranged so that the first ring is secured to the inner shaft and so that both the second ring and the sealing ring are movable within the annular pocket adjacent to the outer shaft. The annular pocket may be formed by end rings disposed about a spacer ring. The end rings and the spacer ring may be secured to each other and the outer shaft via a pin or other suitable means understood in the art. In some embodiments, one end ring may be integral to or an additional element of the outer shaft. In preferred embodiments, the sealing ring and the spacer ring are separated by a gap so that the sealing ring is radially movable within the pocket. The end rings are sufficiently separated so that the sealing ring is axially movable between the end rings. In preferred embodiments, the sealing ring is biased toward and sealingly engages one of the end rings. In some embodiments, a face seal may be formable along either end ring for bi-directional sealing functionality.

In other embodiments, the interposable seal may be arranged so that the first ring is secured to the outer shaft and so that both the second ring and the sealing ring are movable within the annular pocket adjacent to the inner shaft. The annular pocket may be formed by end rings disposed about a spacer ring. The end rings and the spacer ring may be secured to each other and the inner shaft via a pin or other suitable means understood in the art. In some embodiments, one end ring may be integral to or an additional element of the inner shaft. In preferred embodiments, the sealing ring and the spacer ring are separated by a gap so that the sealing ring is radially movable within the pocket. The end rings are sufficiently separated so that the sealing ring is axially movable between the end rings. In preferred embodiments, the sealing ring is biased toward and sealingly engages one of the end rings. In some embodiments, a face seal may be formable along either end ring for bi-directional sealing functionality.

It is understood within the art that the application of traditional piston-ring type sealing between shafts often results in significant circumferential wear to the sealing ring. This problem is remedied by one or more embodiments described herein by firmly seating a diametrical surface of a sealing ring on a corresponding diametrical surface of one of the shafts.

One or more of the following advantages may be realized by an embodiment of the interposable seal assembly. In one aspect, the interposable seal assembly avoids the gap or the clearance typical within circumferential-sealing intershaft assemblies, thereby minimizing fluid flow between the sides. In another aspect, the interposable seal assembly minimizes contact between the sealing ring and the end rings, thereby avoiding a source of wear, heat, and stress. In another aspect, the resiliency or the deformability of the annular member of the interposable seal assembly maintains the face seal between the sealing ring and an end ring during excursions between the shafts. In another aspect, the resiliency or the deformability of the annular member of the interposable seal assembly minimizes forces applied by the face of the sealing ring onto the sealing surface of an end ring, thereby minimizing a source of wear, heat, and stress. In another aspect of the invention, the resiliency of the annular member of the interposable seal assembly permits the seal ring to self-center, separate or otherwise disengage from an end ring after contact between the face of the sealing ring and the sealing surface of the end ring, thereby minimizing a source of wear, heat, and stress.

The above and other objectives, features, and advantages of the present disclosure will become better understood from the following description, appended claims, and accompanying drawings, in which like reference numerals designate the same or similar elements.

4. Brief Description of the Drawings

Additional aspects, features, and advantages of the disclosure will be understood and will become more readily apparent when the disclosure is considered in light of the following description made in conjunction with the accompanying drawings:

FIG. l is a cross-sectional view illustrating an interposable seal assembly (lower half not shown) between an inner shaft and an outer shaft wherein a first ring at an inner end of an annular member is secured to the inner shaft and a second ring with a sealing ring thereon at an outer end of the annular member is disposed within an annular pocket between a pair of end rings secured to the outer shaft whereby the sealing ring forms a face seal along a sealing surface of one end ring in accordance with an embodiment of the invention;

FIG. 2 is a cross-sectional view illustrating an interposable seal assembly (lower half not shown) between an inner shaft and an outer shaft wherein a first ring at an outer end of an annular member is secured to the outer shaft and a second ring with a sealing ring thereon at an inner end of the annular member is disposed within an annular pocket between a pair of end rings secured to the inner shaft whereby the sealing ring forms a face seal along a sealing surface of one end ring in accordance with an embodiment of the invention;

FIG. 3 is a cross-sectional view illustrating a first ring, a second ring, an annular member, and a sealing ring of an interposable seal assembly (other half not shown) wherein the sealing ring includes a first portion wider than a second portion in accordance with an embodiment of the invention;

FIG. 4 is a cross-sectional view illustrating a first ring, a second ring, an annular member, and a sealing ring of an interposable seal assembly (other half not shown) wherein one end of the annular member is secured at a joint along a surface of the first ring and another end of the annular member is secured at a joint along a surface of the second ring in accordance with an embodiment of the invention;

FIG. 5 is a cross-sectional view illustrating a first ring, a second ring, an annular member, and a sealing ring of an interposable seal assembly (other half not shown) wherein one end of the annular member is secured within a pocket along a surface of the first ring and another end of the annular member is secured within a pocket along a surface of the second ring in accordance with an embodiment of the invention;

FIG. 6 is a cross-sectional view illustrating a first ring, a second ring, an annular member, and a sealing ring of an interposable seal assembly (other half not shown) wherein one end of the annular member is movably secured within a pocket along a surface of the first ring and another end of the annular member is movably secured within a pocket along a surface of the second ring in accordance with an embodiment of the invention; FIG. 7a is a cross-sectional view illustrating an annular member of an interposable seal assembly wherein the annular member includes angular crests disposed in an alternating pattern which form an example non-planar shape between an outer end and an inner end about an opening in accordance with an embodiment of the invention;

FIG. 7b is a plan view further illustrating the annular member in FIG. 7a in accordance with an embodiment of the invention;

FIG. 8 is a cross-sectional view illustrating an annular member of an interposable seal assembly wherein the annular member includes non-angular crests disposed in an alternating pattern which form an example non-planar shape between an outer end and an inner end about an opening in accordance with an embodiment of the invention;

FIG. 9 is a cross-sectional view illustrating an annular member of an interposable seal assembly wherein the annular member is planar shaped between an outer end and an inner end about an opening in accordance with an embodiment of the invention;

FIG. 10 is a cross-sectional view illustrating a first ring, a second ring, a pair of annular members, and a sealing ring of an interposable seal assembly (other half not shown) wherein each annular member is secured to and between the first ring and the second ring to form a paired arrangement of annular members in accordance with an embodiment of the invention; and

FIG. 11 is a cross-sectional view illustrating a first ring, a second ring, an annular member, a sealing ring, end rings, a spacer ring, and a gap of an interposable seal assembly (other half not shown) wherein two such interposable seal assemblies are disposed in a side-to-side arrangement in accordance with an embodiment of the invention.

5. Modes for Carrying Out the Disclosure

Reference will now be made in detail to several embodiments of the disclosure that are illustrated in the accompanying drawings. Wherever possible, same or similar reference numerals may be used in the drawings and the description to refer to the same or like parts. While features of various embodiments are separately described herein, it is understood that such features may be combinable to form other additional embodiments.

One or more components described herein may be manufactured via methods, processes, and techniques understood in the art, including, but not limited to, machining, molding, forming, casting, or three-dimensional printing.

The drawing figures are not necessarily drawn to scale, but instead are drawn to provide a better understanding of the components thereof, and are not intended to be limiting in scope, but to provide exemplary illustrations.

Referring now to FIGS. 1 and 2, the interposable seal assembly 1 is sealingly positioned between a pair of coaxial shafts 8, 9. One shaft 8 is sometimes referred to as the inner shaft. Another shaft 9 is sometimes referred to as the outer shaft. One or both shafts 8, 9 may be rotatable about a centerline 10. Dually-rotatable shafts 8, 9 may be either co-rotated or counter-rotated. In some end uses, shaft 8, 9 may also refer to a rotatable runner or a non-rotatable frame.

Referring again to FIGS. 1 and 2, the interposable seal assembly 1 is configured between the shafts 8, 9 so as to sealingly separate a first side 11 at one end of the interposable seal assembly 1 from a second side 12 at another end of the interposable seal assembly 1. The position of the interposable seal assembly 1 between the shafts 8, 9 forms a barrier between the first side 11 and the second side 12. In preferred embodiments, the interposable seal assembly 1 prevents or limits a fluid at a higher pressure and/or temperature within the first side 11 from entering the second side 12 or a fluid at a higher pressure and/or temperature within the second side 12 from entering the first side 11.

Referring again to FIGS. 1 and 2, the interposable seal assembly 1 may include a first ring 2, a second ring 3, an annular member 4, a sealing ring 5, and an annular pocket 16. Components of the interposable seal assembly 1 are arranged to provide a face seal 37 either adjacent to the outer shaft 9 as illustrated in FIG. 1 or adjacent to the inner shaft 8 as illustrated in FIG. 2.

Referring now to FIG. 1, the first ring 2 may comprise one or more metals in part or whole or other material(s) suitable for the application. The first ring 2 is sized and shaped so as to contact the outer surface 26 of the inner shaft 8. The first ring 2 is secured to the shaft 8 so as to prevent or limit relative movement between the first ring 2 and the shaft 8. In preferred embodiments, the first ring 2 may be secured between a shoulder 24 and a locking ring 25. The shoulder 24 may be either a part of or an addition to the shaft 8 which extends outward from the shaft 8. In some embodiments, the locking ring 25 may be slidable onto the shaft 8 and securable thereto via a threaded engagement, the latter not shown. In other embodiments, the locking ring 25 may include two or more parts fastened about the shaft 8 via an inward clamping arrangement. Other arrangements and assembly means are possible for securing the first ring 2 to the shaft 8. Regardless as to the specific examples provided herein, it is understood that the first ring 2 is secured to the shaft 8 so as to prevent or limit axial and radial movement therebetween.

Referring again to FIG. 1, the second ring 3 may comprise one or more metals in part or whole or other material(s) suitable for the application. The second ring 3 is larger diameter-wise than the first ring 2. The second ring 3 is movable with respect to the outer shaft 9. In preferred embodiments, the second ring 3 is less wide than the first ring 2 and the rings 2, 3 are disposed in a concentric arrangement.

Referring again to FIG. 1, the annular member 4 is generally, disk shaped and comprising a metal, non-limiting examples including stainless steel or Inconel, or other material(s) suitable for the application. The annular member 4 is sized and shaped so as to facilitate cooperation with other elements of the interposable seal assembly 1 to enable sealing between the shafts 8, 9. The annular member 4 is disposed between and secured to the first ring 2 and the second ring 3. The annular member 4 has a pair of ends 6, each configured to facilitate separate attachment to the first ring 2 and the second ring 3. In preferred embodiments, the innermost end 6 is circular shaped to enable attachment along an outer surface 28 of the first ring 2 and the outermost end 6 is circular shaped to enable attachment along an inner surface 28 of the second ring 3. Other shapes are possible for the ends 6.

Referring again to FIG. 1, the sealing ring 5 may comprise one or more sealing compatible materials, one non-limiting example being carbon. The second ring 3 is secured along an inward surface 14 of the sealing ring 5 so that the sealing ring 5 is movable with the second ring 3. In some embodiments, the second ring 3 and the sealing ring 5 are secured via a press fit thereby fixing the second ring 3 and the sealing ring 5 in a concentric arrangement. In other embodiments, the second ring 3 and the sealing ring 5 are secured via a shrink fit whereby the second ring 3 is cooled or then returned to ambient temperature thereby fixing the second ring 4 and the sealing ring 5 in a concentric arrangement. Other assembly means understood in the art may be applicable.

Referring again to FIG. 1, a pair of end rings 13 may comprise one or more metals or other material(s) suitable for the application. The end rings 13 are arranged so as to inwardly extend toward the shaft 8. In some embodiments, the end rings 13 may include a wear-resistant coating, one non-limiting example being chrome. The end rings 13 are secured to the outer shaft 9 along the inner surface 20 thereof so as to prevent or limit relative movement by and between the end rings 13 and the shaft 9. In preferred embodiments, the end rings 13 may be secured between a shoulder 21 and a locking ring 19 wherein the end rings 13 are separately disposed about an optional spacer ring 15, the latter comprising one or more metals or other material(s) suitable for the application. The shoulder 21 may be either a part of or an addition to the shaft 9 which extends inward therefrom. In some embodiments, the locking ring 19 may be sized and shaped so as to be slidable onto the shaft 9 and securable thereto via a threaded engagement, the latter not shown. In other embodiments, the locking ring 19 may include two or more parts fastened about the shaft 9 via an outward clamping arrangement. In yet other embodiments, a pin 18 may be slidable through the end rings 13 and the spacer ring 15, and optionally into the outer shaft 9 at the shoulder 21. The pin 18 may secure the end rings 13 to the spacer ring 15 and the shaft 9 and/or prevent relative rotation between the end rings 13, the spacer ring 15, and the shaft 9. Other arrangements are possible for securing the end rings 13 to the shaft 9. Regardless as to the specific examples provided herein, it is understood that both end rings 13 are secured to the shaft 9 so as to prevent or limit relative movement therebetween. In some embodiments, the first ring 2 may be press fit onto the inner shaft 8, the end rings 13 may be press fit onto the outer shaft 9, and/or the spacer ring 15 may be press onto the outer shaft 9.

Referring again to FIG. 1, the end rings 13 are separately secured to the shaft 9 so as to form an annular pocket 16 therebetween. The annular pocket 16 is configured to receive the sealing ring 5. The sealing ring 5 is less wide than the annular pocket 16. In preferred embodiments, the sealing ring 5 is separated from either the spacer ring 15 or the shaft 9 via a gap 17. The second ring 3 is movable within the annular pocket 16 between the end rings 13. This arrangement permits the sealing ring 5 to axially move with respect to the end rings 13 and the end rings 13 to axially move with respect to the sealing ring 5. The gap 17 also permits the sealing ring 5 to radially move with respect to the spacer ring 15 or the shaft 9 and the spacer ring 15 or the shaft 9 to radially move with respect to the sealing ring 5.

Referring again to FIG. 1, each end ring 13 has a sealing surface 22 or 23 disposed at opposite sides of the annular pocket 16. Each sealing surface 22, 23 is arranged to permit engagement with one of two faces 39 of the sealing ring 5. In some embodiments, a contact arrangement between a face 39 and a sealing surface 22 or 23 permits formation of a face seal 37 which prevents or limits fluid flow therebetween. In other embodiments, a near-contact arrangement, whereby a face 39 and a sealing surface 22 or 23 are closely positioned but do not contact, permits formation of a face seal 37 which prevents or limits fluid flow therebetween. Leakage across the face seal 37, if any, may be further limited by the position of the sealing ring 5 with respect to the non-sealing end ring 13, the spacer ring 15, or the shaft 9. A sealing surface 22 or 23 may include optional hydrostatic or hydrodynamic grooves. In preferred embodiments, the sealing surfaces 22 and 23 are sufficiently spaced so that only one face seal 37 is possible within the annular pocket 16 at a time. In yet other preferred embodiments, the sealing ring 5 is initially biased in the direction of one sealing surface 22 or 23, the latter illustrated in FIG. 1, so that a face seal 37 is formed with one end ring 13. The initial bias may correlate with the pressure differential between the first side 11 and the second side 12 wherein the face seal 37 is often formed with the end ring 13 at the lower-pressure side. Although an initial bias may favor a face seal 37 along one sealing surface 23 or 22, it is further understood that a face seal 37 may be formable along the other sealing surface 22 or 23 whenever an excursion by and between the shafts 8, 9 facilitates for a closer arrangement between one of the faces 39 and one of the sealing surfaces 22 or 23. This latter optional feature enables bi-directional sealing between the sealing ring 5 and the end rings 13.

Referring again to FIG. 1, the annular member 4 is adapted to maintain a face seal 37. One or more parameters of the annular member 4, examples including but not limited to thickness, thickness profile, cross-sectional shape, plan-view shape, or material property(ies), may allow the annular member 4 to move or otherwise change shape whenever an end ring 13 contacts the sealing ring 5 as a result of a radial movement 32 and/or an axial movement 33 by or between the shafts 8, 9 or some other event. In some embodiments, the annular member 4 may be resilient, that is capable of recoiling or springing back after being bent, stretched, compressed or shape-wise changed in some fashion in part or whole. A resilient annular member 4 may recover its original shape in part or whole. In other embodiments, the annular member 4 may be deformable, that is capable of retaining a shape after being bent, stretched, compressed or shape-wise changed in part or whole. A deformable annular member 4 would not necessarily recover its original shape unless subsequent deformation(s) cause it to do so. In preferred embodiments, the annular member 4 may maintain a contact arrangement or a non-contact arrangement between the sealing ring 5 and the end ring 13 as required for proper sealing by the face seal 37 at the interface between a face 39 and a sealing surface 22 or 23. A contact arrangement may or may not impose a force onto the end ring 13 by the sealing ring 5. In some embodiments, the annular member 4 may either resiliently or deformably alter its shape after contact with a sealing surface 22 or 23 wherein contact is maintained for a number of revolutions in part or whole greater than 0 after which the annular member 4 changes shape to favor non-contact at the face seal 37. The adaptiveness of the annular member 4 may continuously maintain the face seal 37 in some embodiments or maintain the face seal 37 before and after an event which otherwise reduces the effectiveness of the face seal 37 in other embodiments.

Referring now to FIG. 2, the first ring 2 may comprise one or more metals in part or whole or other material(s) suitable for the application. The first ring 2 is sized and shaped so as to contact the inner surface 20 of the outer shaft 9. The first ring 2 is secured to the shaft 9 so as to prevent or limit relative movement between the first ring 2 and the shaft 9. In preferred embodiments, the first ring 2 may be secured between a shoulder 21 and a locking ring 19. The shoulder 21 may be either a part of or an addition to the shaft 9 which extends inward from the shaft 9. In some embodiments, the locking ring 19 may be slidable onto the shaft 9 and securable thereto via a threaded engagement, the latter not shown. In other embodiments, the locking ring 19 may include two or more parts fastened to the shaft 9 in an outward clamping arrangement. Other arrangements and assembly means are possible for securing the first ring 2 to the shaft 9. Regardless as to the specific examples provided herein, it is understood that the first ring 2 is secured to the shaft 9 so as to prevent or limit axial and radial movement therebetween. Referring again to FIG. 2, the second ring 3 may comprise one or more metals in part or whole or other material(s) suitable for the application. The second ring 3 is smaller diameter-wise than the first ring 2. The second ring 3 is movable with respect to the inner shaft 8. In preferred embodiments, the second ring 3 is less wide than the first ring 2 and the rings 2, 3 are disposed in a concentric arrangement.

Referring again to FIG. 2, the annular member 4 is generally, disk shaped and comprising a metal, non-limiting examples including stainless steel or Inconel, or other material(s) suitable for the application. The annular member 4 is sized and shaped so as to facilitate cooperation with other elements of the interposable seal assembly 1 to enable sealing between the shafts 8, 9. The annular member 4 is disposed between and secured to the first ring 2 and the second ring 3. The annular member 4 has a pair of ends 6, each configured to facilitate separate attachment to the first ring 2 and the second ring 3. In preferred embodiments, the innermost end 6 is circular shaped to enable attachment along an outer surface 28 of the second ring 3 and the outermost end 6 is circular shaped to enable attachment along an inner surface 28 of the first ring 2. Other shapes are possible for the ends 6.

Referring again to FIG. 2, the sealing ring 5 may comprise one or more sealing compatible materials, one non-limiting example being carbon. The second ring 3 is secured along an outward surface 14 of the sealing ring 5 so that the sealing ring 5 is movable with the second ring 3. In some embodiments, the second ring 3 and the sealing ring 5 are secured via a press fit thereby fixing the second ring 3 and the sealing ring 5 in a concentric arrangement. In other embodiments, the second ring 3 and the sealing ring 5 are secured via a shrink fit whereby the second ring 3 is heated or then returned to ambient temperature thereby fixing the second ring 3 and the sealing ring 5 in a concentric arrangement. Other assembly means understood in the art may be applicable.

Referring again to FIG. 2, a pair of end rings 13 may comprise one or more metals or other material(s) suitable for the application. The end rings 13 are arranged so as to outwardly extend toward the shaft 9. In some embodiments, the end rings 13 may include a wear-resistant coating, one non-limiting example being chrome. The end rings 13 are secured to the inner shaft 8 along the outer surface 26 thereof so as to prevent or limited relative movement by and between the end rings 13 and the shaft 8. In preferred embodiments, the end rings 13 may be secured between a shoulder 24 and a locking ring 25 wherein the end rings 13 are separately disposed about an optional spacer ring 15, the latter comprising one or more metals or other material(s) suitable for the application. The shoulder 24 may be either a part of or an addition to the shaft 8 which extends outward therefrom. In some embodiments, the locking ring 25 may be sized and shaped so as to be slidable onto the shaft 8 and securable thereto via a threaded engagement, the latter not shown. In other embodiments, the locking ring 25 may include two or more parts fastened about the shaft 8 via an inward clamping arrangement. In yet other embodiments, a pin 18 may be slidable through the end rings 13 and the spacer ring 15, and optionally into the inner shaft 8 at the shoulder 24. The pin 18 may secure the end rings 13 to the spacer ring 15 and the shaft 8 and/or prevent relative rotation between the end rings 13, the spacer ring 15, and the shaft 8. Other arrangements are possible for securing the end rings 13 to the shaft 8. Regardless as to the specific examples provided herein, it is understood that both end rings 13 are secured to the shaft 8 so as to prevent or limit relative movement therebetween. In some embodiments, the first ring 2 may be press fit onto the outer shaft 9, the end rings 13 may be press fit onto the inner shaft 8, and/or the spacer ring 15 may be press onto the inner shaft 8.

Referring again to FIG. 2, the end rings 13 are separately secured to the shaft 8 so as to form an annular pocket 16 therebetween. The annular pocket 16 is configured to receive the sealing ring 5. The sealing ring 5 is less wide than the annular pocket 16. In preferred embodiments, the sealing ring 5 is separated from either the spacer ring 15 or the shaft 8 via a gap 17. The second ring 3 is movable within the annular pocket 16 between the end rings 13. This arrangement permits the sealing ring 5 to axially move with respect to the end rings 13 and the end rings 13 to axially move with respect to the sealing ring 5. The gap 17 also permits the sealing ring 5 to radially move with respect to the spacer ring 15 or the shaft 8 and the spacer ring 15 or the shaft 8 to radially move with respect to the sealing ring 5.

Referring again to FIG. 2, each end ring 13 has a sealing surface 22 or 23 disposed at opposite sides of the annular pocket 16. Each sealing surface 22, 23 is arranged to permit engagement with one of the two faces 39 of the sealing ring 5. In some embodiments, a contact arrangement between a face 39 and a sealing surface 22 or 23 permits formation of a face seal 37 which prevents or limits fluid flow therebetween. In other embodiments, a near-contact arrangement, whereby a face 39 and a sealing surface 22 or 23 are closely positioned but do not contact, permits formation of a face seal 37 which prevents or limits fluid flow therebetween. Leakage across the face seal 37, if any, may be further limited by the position of the sealing ring 5 with respect to the non-sealing end ring 13, the spacer ring 15, or the shaft 8. A sealing surface 22 or 23 may include optional hydrostatic or hydrodynamic grooves. In preferred embodiments, the sealing surfaces 22 and 23 are sufficiently spaced so that only one face seal 37 is possible within the annular pocket 16 at a time. In yet other preferred embodiments, the sealing ring 5 is initially biased in the direction of one sealing surface 22 or 23, the latter illustrated in FIG. 2, so that a face seal 37 is formed with one end ring 13. The initial bias may correlate with the pressure differential between the first side 11 and the second side 12 wherein the face seal 37 is often formed with the end ring 13 at the lower-pressure side. Although an initial bias may favor a face seal 37 along one sealing surface 23 or 22, it is further understood that a face seal 37 may be formable along the other sealing surface 22 or 23 whenever an excursion by and between the shafts 8, 9 facilitates for a closer arrangement between one of the faces 39 and one of the sealing surfaces 22 or 23. This latter optional feature enables bi-directional sealing between the sealing ring 5 and the end rings 13.

Referring again to FIG. 2, the annular member 4 is adapted to maintain a face seal 37. One or more parameters of the annular member 4, examples including but not limited to thickness, thickness profile, cross-sectional shape, plan-view shape, or material property(ies), may allow the annular member 4 to move or otherwise change shape whenever an end ring 13 contacts the sealing ring 5 as a result of a radial movement 32 and/or an axial movement 33 by or between the shafts 8, 9 or some other event. In some embodiments, the annular member 4 may be resilient, that is capable of recoiling or springing back after being bent, stretched, compressed or shape-wise changed in some fashion in part or whole. A resilient annular member 4 may recover its original shape in part or whole. In other embodiments, the annular member 4 may be deformable, that is capable of retaining a shape after being bent, stretched, compressed or shape-wise changed in part or whole. A deformable annular member 4 would not necessarily recover its original shape unless subsequent deformation(s) cause it to do so. In preferred embodiments, the annular member 4 may maintain a contact arrangement or a non-contact arrangement between the sealing ring 5 and the end ring 13 as required for proper sealing by the face seal 37 at the interface between a face 39 and a sealing surface 22 or 23. A contact arrangement may or may not impose a force onto the end ring 13 by the sealing ring 5. In some embodiments, the annular member 4 may either resiliently or deformably alter its shape after contact with a sealing surface 22 or 23 wherein contact is maintained for a number of revolutions in part or whole greater than 0 after which the annular member 4 changes shape to favor non-contact at the face seal 37. The adaptiveness of the annular member 4 may continuously maintain the face seal 37 in some embodiments or maintain the face seal 37 before and after an event which otherwise reduces the effectiveness of the face seal 37 in other embodiments.

Referring now to FIG. 3, the sealing ring 5 in alternate embodiments of the interposable seal assembly 1 may include a first portion 34 and a second portion 35. The second portion 35 contacts the second ring 3 so that the sealing ring 5 is secured to the second ring 3. The annular member 4 is secured along the surface 28 of the second ring 3 opposite from the second portion 35. The annular member 4 is also secured along the surface 28 of the first ring 2. This arrangement positions the annular member 4 between the first ring 2 and the second ring 3. In preferred embodiments, the second ring 3 is less wide than the second portion 35, the second portion 35 is less wide than the first portion 34, and the first portion 34 is less wide than the first ring 2. It is also preferred that the sealing faces 39 along the sealing ring 5 at least initially reside along the first portion 34; however, the faces 39 could in some applications eventually extend to the second portion 35 dependent on the degree and rate of wear to the first portion 34. The width variation along the sealing ring 5 may be beneficial in certain applications by minimizing contact between the end rings 13 and a nonsealing component such as the second ring 3.

Referring now to FIG. 4, the annular member 4 in some alternate embodiments of the interposable seal assembly 1 may be directly and separately secured at the surface 28 of the first ring 2 and/or the surface 28 of the second ring 3. One end 6 of the annular member 4 may contact or nearly contact the surface 28 of the first ring 2 and another end 6 of the annular member 4 may contact or nearly contact the surface 28 of the second ring 3. Each end 6 may be secured to the respective ring 2 or 3 via a joint 27. The joint 27 may be formed via a joining material suitable for the application. In several non -limiting examples, a joining material for a joint 27 may be applied via welding, soldering, or brazing one or both sides of the annular member 4 and the first ring 2 adjacent to and about an end 6 or the annular member 4 and the second ring 3 adjacent to and about another end 6. The joint 27 between the second ring 3 and the annular member 4 may be formed either before or after the second ring 3 and the sealing ring 5 are secured.

Referring now to FIG. 5, the annular member 4 in some alternate embodiments of the interposable seal assembly 1 may be directly and separately secured at the surface 28 of the first ring 2 and/or the surface 28 of the second ring 3. One end 6 of the annular member 4 may extend into a pocket 29 along the surface 28 of the first ring 2 and another end 6 of the annular member 4 may extend into a pocket

29 along the surface 28 of the second ring 3. Each end 6 may be secured to the respective ring 2 or 3 via a joint 27. The joint 27 may be formed via a joining material suitable for the application. In several non-limiting examples, a joining material for a joint 27 may be applied via welding, soldering, or brazing one or both sides of the annular member 4 and the first ring 2 within the pocket 29 adjacent to and about an end 6 or the annular member 4 and the second ring 3 within the pocket 29 adjacent to and about another end 6. The joint 27 between the second ring 3 and the annular member 4 may be formed either before or after the second ring 3 and the sealing ring 5 are secured.

Referring now to FIG. 6, the annular member 4 in some alternate embodiments of the interposable seal assembly 1 may be directly and separately secured via a rotatable joint 40 along the surface 28 of the first ring 2 and/or the surface 28 of the second ring 3. The rotatable joint 40 may permit rotation or pivot action similar to a ball-and-socket arrangement. One end 6 of the annular member 4 may include a shaped flange 36 which extends into a complementary shaped pocket

30 along the surface 28 of the first ring 2 and/or another end 6 of the annular member 4 may include a shaped flange 36 which extends into a complementary shaped pocket 30 along the surface 28 of the second ring 3. The shaped flange 36 may be a ringshaped structure secured to an end 6 of the annular member 4, or a curled or bent portion of the annular member 4, or another design element or feature compatible with j oint-like movement. In preferred embodiments, the shaped flange 36 and the shaped pocket 30 may have a substantially-circular cross section. In some embodiments, the shaped flange 36 may lockingly engage the shaped pocket 30 to prevent separation. It is generally understood that the shaped flange 36 and the shaped pocket 30 should permit relative movement between two or more of the first ring 2, the second ring 3, and the annular member 4. Preferred embodiments of the rotatable joint 40 should limit or prevent leakage across the interposable seal assembly 1. In other preferred embodiments, the shaped flange 36 should rotatably and sealingly engage the shaped pocket 30 so as to limit or prevent leakage therebetween. The rotatable joint 40 between the second ring 3 and the annular member 4 may be formed either before or after the second ring 3 and the sealing ring 5 are secured.

Referring now to FIGS. 7a and 7b, the annular member 4 is bounded by a pair of ends 6. In preferred embodiments, the annular member 4 is generally disk-shaped as illustrated in FIG. 7b, although other shapes are possible. One end 6 defines an opening 31 through the annular member 4. In preferred embodiments, the opening 31 is circular and centered within the annular member 4. The inner shaft 8 passes through the opening 31. The other end 6 defines a perimeter 41 of the annular member 4. In preferred embodiments, the perimeter 41 is circular and concentric with respect to the opening 31. The first ring 2 and the second ring 3 are separately secured to the ends 6. In FIG. 1, the first ring 2 is secured to the end 6 within the opening 31 and the second ring 3 is secured to the end 6 about the perimeter 41. In FIG. 2, the first ring 2 is secured to the end 6 about the perimeter 41 and the second ring 3 is secured to the end 6 within the opening 31.

Referring now to FIGS. 7a, 7b, 8, and 9, the annular member 4 in some alternate embodiments of the interposable seal assembly 1 may include a non-planar cross section by way of the non-limiting examples in FIGS. 7a and 8 or a planar cross section by way of the non-limiting example in FIG. 9. Non-planar cross sections may include, for example, a plurality of crests 7 which extend outward from the annular member 4 to form a corrugated cross section as illustrated in FIGS. 7a, 7b, and 8. The crests 7 may be more angular as illustrated in FIG. 7a or less angular as illustrated in FIG. 8. The pattern of the non-planar sections may include a variety of shapes and designs which are symmetric, non-symmetric, alternating, non-alternating, uniform, non-uniform, variable or invariable. Planar cross sections may include generally- planar shaped structures with a uniform or varied thickness. Non-planar and planar designs may enhance or impede the resiliency or the deformability of the annular member 4. Referring now to FIG. 10, it may be advantageous in alternate embodiments to the interposable seal assembly 1 to include a second annular member 38 between the first ring 2 and the second ring 3 and adjacent to the annular member 4. The annular members 4, 38 may be separately secured to the respective surfaces 28 of the first ring 2 and the second ring 3 as otherwise described herein, either before or after the second ring 3 and the sealing ring 5 are secured. The annular member 4 and the second annular member 38 may be the same design or different designs, the former illustrated in FIG. 10. This design approach may be beneficial to applications, but not limited thereto, wherein an interposable seal assembly 1 might be subjected to high loads, frequent loading, or large deflections or wherein the pressure differential about the interposable seal assembly 1 is high or highly variable.

Referring now to FIG. 11, it may be advantageous in alternate embodiments to arrange two interposable seal assembly 1 between the first side 11 and the second side 12. Each interposable seal assembly 1 would include a first ring 2, a second ring 3, an annular member 4, a sealing ring 5, end rings 13, and an annular pocket 16, and may further optionally include a spacer 15 and a gap 17. The interposable seal assemblies 1 may be positioned in a contact arrangement, such as illustrated in FIG. 11, or a noncontact arrangement with a separation between adjacent end rings 13 and/or first rings 2. In some contact arrangements, the innermost end rings 13 may form a single end ring 13 as indicated by the dashed line in FIG. 11. The sealing rings 5 may be oppositely disposed whereby one sealing ring 5 contacts the sealing surface 23 and the other sealing ring 5 contacts the sealing surface 22 so that the face seals 37 are adjacently disposed. This arrangement may result from the respective pressure applied to each interposable seal assembly 1 or from a biasing feature(s) of the design. Regardless, other sealing arrangements are possible between the sealing rings 5 and respective sealing surfaces 22, 23 either as a feature of a particular design or as imposed by conditions adjacent to the interposable seal assemblies 1. This design approach may be beneficial to applications, but not limited thereto, wherein redundancy is necessary due to performance requirements by the seal system or conditions adjacent to the seal system.

While the disclosure is susceptible to various modifications and alternative constructions, certain illustrative embodiments are shown in the drawings and are described in detail herein. It should be understood, however, there is no intention to limit the disclosure to the specific embodiments disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, combinations, and equivalents falling into the spirit and scope of the disclosure.

As is evident from the explanation herein, the disclosure in its various embodiments may be appropriate, but not limited, to applications that require sealing between a rotatable runner and a non-rotatable frame, or between a rotating shaft and a non-rotating shaft, or between a pair of co-rotating shafts, or between a pair of counter-rotating shafts.