Seal assembly with thermal expansion restricter

Information

  • Patent Grant
  • 6318729
  • Patent Number
    6,318,729
  • Date Filed
    Friday, January 21, 2000
    24 years ago
  • Date Issued
    Tuesday, November 20, 2001
    23 years ago
Abstract
A seal assembly having a first seal with a first mating surface and a recess in the first mating surface, and a second seal having a second mating surface and a recess in the second mating surface. The first mating surface of the first seal is adjacent to the second mating surface of the second seal and a first thermal expansion restricter is received simultaneously into the recesses of the first and second mating surfaces of the first and second seals, respectively.
Description




BACKGROUND OF THE INVENTION




The present invention is directed generally to the field of seals for use in statically and dynamically sealing an annular cavity formed between two concentric tubes and more particularly to a restricter incorporated into a multi-element seal assembly to assist in restricting temperature-induced radial growth of the seals.




Seals take many shapes and forms and play a critical role in many devices. They are employed in settings wherein the components between which the seals are used are either static or dynamic with respect to one another. Moreover, the environment in which such seals are used may present extreme conditions such as high or low temperatures or transitions between the two, high pressure, friction, and chemical exposure. Seals used in this environment have a very short life, often failing after only a small number of cycles. Materials are therefore strategically selected to address one or more of the environmental conditions. One material may not address all conditions, but the combination of several seals made from different materials will typically address the majority of environmental conditions encountered.




A significant problem in designing seal assemblies for environments where conditions vary widely is that the materials selected for the seals may not all react in the same way to the environmental conditions. Such reactions may, in fact, be adverse to their sealing function. This difficulty is acutely manifested where extreme temperature changes are encountered. In such cases, the compensation for thermal conditions must be so great that if the seal is designed primarily to seal at higher temperatures, it loses its ability to seal at lower temperatures and vice versa.




Exemplary of these settings where such vexing environmental conditions are encountered are tools for use in subterranean downhole wells. Following the drilling of a downhole well, a string of casing is cemented in place to form an outer housing for the well hole. The casing is then perforated to permit the flow of fluids into the interior of the casing. Fluids are extracted from the casing via a string of conduits called production tubing or work tubes which are suspended concentrically within the casing. To permit the efficient extraction of fluids from the casing via the work tubes, or to permit the infusion of chemical inhibitors, stimulants or the like into the well hole, the work tubes are provided with a downhole well tool, generally located deep within the well, which acts as a valve to control the communication of fluids between the interior of the work tubes and the annular region between the work tubes and the casing.




Downhole well tools are well known in the drilling/extraction industry. Such downhole well tools are disclosed in, for example, U.S. Pat. No. 5,263,683 issued to Wong, entitled “Sliding Sleeve Valve,” U.S. Pat. No. 5,316,084 issued to Murray et al. and U.S. Pat. No. 5,156,220 issued to Forehand et al., both entitled “Well Tool With Sealing Means.” Such downhole well tools generally are provided with an outer housing which is an outer, generally tubular member, having threads on each end for connection to the work tubes and have a port or series of ports in the outer housing, generally arranged in a circumferential pattern around the midsection of the housing. Positioned concentrically and slidably within the housing is an inner, generally tubular member or sliding member, also having a port or series of ports arranged in a circumferential pattern around its midsection. The annular region between the outer housing and the sliding member is sealed at its upper end, above the housing ports, by a seal and at its lower end, below the housing ports, by another seal.




The valving function of the downhole well tool is accomplished by moving the sliding member longitudinally within the outer housing such that the ports of the sliding member are moved into and out of fluid communication with the housing ports. The sliding member is manipulated between the open and closed positions by means of a wireline, remedial coiled tubing, electric line, or any other well known mechanism controllable from atop the well hole. To permit fluid communication between the region within the work tubes and within the annular region outside the work tubes and within the casing, the sliding member is thus slidably moved to a position whereby the ports of the sliding member are located between the seals located above and below the housing ports. To discontinue or prevent fluid communication between the interior of the work tubes and the exterior of the work tubes, the sliding member is positioned whereby the ports of the sliding member are not located between the seals above and below the housing ports.




Essential to the valving function of the downhole well tool is a reliable sealing engagement between the sliding member and housing both above and below the ports on the housing.




Prior attempts to provide seals capable of withstanding the high temperatures and broad temperature ranges present in the down hole well environment have included the use of various types of polymeric material. Although polymeric materials have proven to be chemically resistant, after prolonged exposure to the high temperatures and broad temperature ranges present within the well hole, seals made from such materials will harden, become brittle, and will fail to provide sealing engagement between the sliding member and housing.




A significant improvement over single-seal designs is provided by prior art designs employing a combination of individual seal elements in a single seal assembly. Examples of such “nested” or multi-element seal assemblies generally known in the art are disclosed in U.S. Pat. No. 4,576,385 issued to Ungchusri et al., entitled “Fluid Packing Assembly With Alternating Diverse Seal Ring Elements” and in U.S. Pat. No. 5,309,993 issued to Coon et al., entitled “Chevron Seal for a Well Tool,” the latter of which is incorporated herein in its entirety by reference. The advantage of such nested seal assemblies is that they permit the designer to combine seals made from several different materials into a single sealing unit. The materials employed can include a combination of metallic and non-metallic materials.




Nested seal assemblies provide the designer with the ability to partially compensate for the widely ranging conditions present in sealing applications, particularly in downhole wells. Whereas some of the individual seal components will function better at lower temperatures, others will function better at higher temperatures.




Thus, the purpose of using seal assemblies is to increase sealing efficiency relative to individual seal elements and to provide the opportunity to combine different types of seals and materials to accomplish sealing under a wide range of environmental conditions.




One significant drawback to any of the prior art seal assemblies, however, including nested seal assemblies, is that high temperatures and broad temperature ranges within the well bore, and of the downhole well tool itself, cause a large degree of thermally-induced growth in the individual seals and in the seal assembly as a whole. This thermally-induced seal growth occurs along the longitudinal axis of the downhole well and tool and in the radial (i.e., perpendicular to the longitudinal axis of the downhole well) direction. While longitudinal growth is not a particularly relevant factor insofar as seal longevity is concerned due to the ability to effectively restrain such growth, radial growth presents great challenges. Radial growth of seals results from the use of seal materials having high coefficients of thermal expansion.




When designing for sealing in environments where large variations in temperature occur, the degree of thermally-induced radial growth can be compensated for during design by sizing the various elements according to the amount of radial growth anticipated. However, as temperatures increase, or as the temperature range increases, compensation using sizing alone is insufficient to accommodate the degree of thermal growth that accompanies such conditions. This is due to the fact that seals cannot be sized to seal only at higher temperatures because the seals would not be capable of sealing at lower temperatures. Alternatively, sizing seals to accommodate the sealing function at lower temperatures can create a situation whereby thermally-induced radial growth creates too much interference at high temperatures. Such interference can cause seal damage or, in more extreme cases, can cause the downhole well tool to seize or lock up, whereby the sliding member cannot slide within the housing, thus leading to costly down time. Moreover, because seal assemblies may include seals made from disparate materials, thermally-induced radial growth is inconsistent among the various seal elements, thus complicating the design process.




The present invention improves on the seal assembly concept by providing a mechanism which restricts the thermal growth of adjacent seals in a seal assembly. The result is that, regardless of the non-metallic material used to make the seals, thermal growth of each seal is restricted, thus leading to greatly improved sealing capacity of the seal assembly, greater reliability, and lower operating costs.




BRIEF SUMMARY OF THE INVENTION




Briefly stated, the present invention is a seal assembly having a first seal with a first mating surface and a recess in the first mating surface, a second seal having a second mating surface and a recess in the second mating surface. The first mating surface of the first seal is adjacent to the second mating surface of the second seal. A first thermal expansion restricter is received simultaneously into the recesses of the first and second mating surfaces of the first and second seals, respectively.




In another aspect, the present invention is a downhole well tool of the type having an outer generally tubular member, and an inner generally tubular member slidably and concentrically positioned within the outer tubular member. The outer tubular member is perforated by an outer tubular port and the inner tubular member is perforated by an inner tubular port. The downhole well tool further includes first and second seal assemblies interposed in an annular region between the outer and inner tubular members. A sealed region is formed between the first and second seal assemblies when one of the outer tubular port and inner tubular port is disposed between the first and second seal assemblies. Each of the first and second seal assemblies includes first and second seals and a first thermal expansion restricter. The first seal has a first mating surface and a recess in the first mating surface. The second seal has a second mating surface and a recess in the second mating surface. The first mating surface of the first seal is adjacent to the second mating surface of the second seal. The first thermal expansion restricter is received simultaneously into the recesses of the first and second mating surfaces of the first and second seals, respectively.











BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS




The foregoing summary, as well as the following detailed description of preferred embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings an embodiment which is presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:





FIG. 1

is a longitudinal, partial sectional view of a subterranean well showing well hole communication apparatus positioned above a well packer during actual production of the well;





FIG. 2

is an enlarged, longitudinally extending quarter sectional view of the downhole well tool shown in

FIG. 1

in a closed position;





FIG. 3

is a greatly enlarged view in torroidal cross-section of a downhole well tool showing a seal assembly in accordance with the prior art;





FIG. 4

is a greatly enlarged, partially-exploded, torroidal cross-sectional view of a preferred embodiment of the seal assembly of the present invention.











DETAILED DESCRIPTION OF THE INVENTION




In the drawings, like numerals are used to indicate like elements throughout. With reference to

FIG. 1

, there is shown a wellbore tool apparatus in which the present invention may be used. It will be recognized by those of ordinary skill in the art that the present invention need not be limited in application to the wellbore tool apparatus as shown, but may have application in any situation wherein static or dynamic sealing under varying temperature conditions is required, including wellbore tools other than the type described hereinbelow, pumps, transmission systems, valving systems, etc.




As shown in

FIG. 1

, a well head


10


including a blow-out preventer


12


is positioned atop a well hole


14


. The well hole


14


includes a casing


16


which generally extends from the top to the bottom of the well hole


14


and which, in essence, forms the lining of the well hole


14


. For purposes of moving fluids into and out of the well hole


14


, there is concentrically located within the casing


16


a wellbore fluid transfer tube


18


, including, at the bottom thereof, a downhole well tool


20


and well packer


22


.




With reference to

FIGS. 1 and 2

, the downhole well tool


20


includes a cylindrical upper housing


24


, which, at its upper end, is secured to the fluid transfer tube


18


by threads


26


. Secured to the lower portion of the upper housing


24


by threaded connection


28


is a cylindrical housing port section


30


which includes outer tubular ports or housing ports


32


perforating the housing port section


30


and disposed about the circumference of the housing port section


30


. Secured to the lower end of the housing port section


30


by threaded connection


34


is a cylindrical lower housing


36


. An additional fluid transfer tube


18


(not shown) or a well packer


22


may be connected to the lower housing


36


via threads


38


. The assembly of the upper housing


24


, housing port section


30


and lower housing


36


forms an outer generally tubular member or tubular housing


37


of the downhole well tool


20


.




Concentrically and slidably positioned within the interior of the tubular housing


37


of the downhole well tool


20


is an inner generally tubular member or sliding member


40


having inner tubular ports or sliding member ports


42


perforating therethrough and disposed about the circumference of the sliding member


40


. Interposed in the annular region formed between the interior cylindrical surface of the tubular housing


37


and the external cylindrical surface of the sliding member


40


to provide a sealing connection is a first seal assembly


44


located proximal to and above the housing ports


32


and a second seal assembly


46


located proximal to and below the housing ports


32


. It will be recognized by those of ordinary skill in the art that the combination of the tubular housing


37


, sliding member


40


, and first and second seal assemblies


44


,


46


provide the valving action of the downhole well tool


20


.




A sealed region


35


is formed between the first and second seal asemblies


44


,


46


when one of the housing ports


32


or sliding member ports


42


is not disposed between the first and second seal assemblies


44


,


46


. More particularly, as the downhole well tool


20


appears in

FIG. 2

, the downhole well tool


20


is in the “closed” position wherein there is no fluid communication between the interior of the downhole well tool


20


and the region within the casing


16


and external to the downhole well tool


20


. Although the housing ports


32


are in fluid communication with the fluid within the casing


16


and external to the downhole well tool


20


, the coaction of the first and second seal assemblies


44


,


46


and the non-perforated portion of the sliding member


40


prevent fluid communication with the region within the downhole well tool


20


. To provide fluid communication, the sliding member


40


is moved by a wireline, remedial coil tubing or other mechanism (not shown) well known to those of ordinary skill in the art to a position wherein the sliding member ports


42


are disposed between the first and second seal assemblies


44


,


46


. In this configuration, because the housing ports


32


and sliding member ports


42


are both located between the first and second seal assemblies


44


,


46


, there is fluid communication between the region within the downhole well tool


20


and the region external to the downhole well tool


20


and within the casing


16


.




It is well recognized by those of ordinary skill in the art that the proper operation of the first and second seal assemblies


44


,


46


is critical to the proper operation of the downhole well tool


20


. Failure of one or both of these seal assemblies can cause great expense to the well operator insofar as the well head


10


(if used), fluid transfer tube


18


, and downhole well tool


20


must be removed from the well hole


14


, the downhole well tool


20


must be disassembled and repaired, and the entire apparatus must be reassembled and reinstalled.




Referring now to

FIG. 3

, there is shown in torroidal cross section a typical prior art seal assembly


100


of the type used for the first and second seal assemblies


44


,


46


. As those of ordinary skill in the art will recognize, prior art seal assemblies


100


are typically composed of various individual seal elements


108


which are nested and cooperate to form a unitary seal when used in a downhole well tool


20


. The prior art seal assembly


100


is shown with a center adapter


102


, and first and second end adapters


104


,


106


. These adapters are generally used not to provide sealing, but are used to retain the seals


108


. The seals


108


are typically chevron seal rings made from thermoplastic material. It is well known by those of ordinary skill in the art to combine seals


108


of different materials such that different operating conditions may be accommodated. Whereas the seals


108


can be designed, i.e., sized, to properly seal at lower operating temperatures, such seals may not seal effectively or may fail at higher operating temperatures due to the thermally-induced radial growth. Conversely, if the seals


108


are designed to properly seal at higher operating temperatures, the seals


108


may not seal at lower operating temperatures. Moreover, when seals of different material composition are used in a set or assembly as shown in

FIG. 3

, designing to accommodate thermally-induced radial growth of the seals


108


presents a significant obstacle to attaining optimal performance.




With reference to

FIG. 4

, there is shown a partially-exploded, torroidal cross-section of a preferred embodiment of the first low radial growth seal assembly


44


in accordance with the present invention. A first seal


202


includes a first mating surface


204


and a recess


206


in the first mating surface


204


. It will be recognized by those of ordinary skill in the art that the first seal


202


, and additional seals described hereinbelow, need not be rings as shown in

FIG. 4

, but alternatively may also be sleeves, split rings, packer or packing type elements, etc. without departing from the spirit and scope of the present invention. In such an alternative embodiment, there could be fewer or more seals than described hereinbelow. A second seal


208


has a second mating surface


210


and a recess


212


in the second mating surface


210


. The first mating surface


204


of the first seal


202


is disposed adjacent to the second mating surface


210


of the second seal


208


. The first and second seals


202


,


208


will generally be made from a non-metallic material, preferably non-elastomeric, thermoplastic materials such as polytetrafluoroethylene-based composite thermoplastic available from Greene Tweed and Company, Kulpsville, Pa., under the trademark AVALON NO. 89 manufactured by their Advante Division in Garden Grove, Calif., or polyetherketone, also available from Greene Tweed and Company. Those of ordinary skill in the art will recognize that the first and second seals


202


,


208


need not be made from the listed materials, but may be made from any of a number of seal materials well known in the art without departing from the spirit and scope of the invention.




A first thermal expansion restricter


214


is received simultaneously into the recesses


206


,


212


of the first and second mating surfaces


204


,


210


of the first and second seals


202


,


208


respectively. The first thermal expansion restricter


214


is preferably made from a material that has thermal growth properties similar to those of the downhole well tool


20


, particularly the upper and lower housings


24


,


36


, housing port section


30


, and sliding member


40


. Preferred materials include chemically-resistant metals such as stainless steel, Inconel (available from Inco Alloys located in Huntington, W.V., Elgiloy (available from Elgiloy Ltd. Partnership located in Elgin, Ill., or filled (including highly filled or reinforced) composites such as glass or carbon fiber with PEEK matrix, glass or carbon fiber with Ryton matrix, glass or carbon with Phenolix available from Automated Dynamics located in Schenectady, N.Y. The first thermal expansion restricter


214


need not be made of these materials, but to accomplish the objective of restricting thermally-induced radial growth of the low radial growth seal assembly


44


, the first thermal expansion restricter


214


must be made from a material with a lower coefficient of thermal expansion than at least one of the seals


202


,


208


into which the restricter


214


is recessed.




By nesting the first and second seals


202


,


208


with the first thermal expansion restricter


214


, thus causing the first and second seals


202


,


208


and the first thermal expansion restricter


214


to act as a single unit, the thermally-induced radial growth of the first seal assembly


44


is thus greatly reduced. The first and second seals


202


,


208


are, therefore, not free to expand due to thermal influences as would normally be expected. The thermal expansion restricter


214


of the preferred embodiment offers this significant advantage without affecting the geometric properties of the first seal assembly


44


. In other words, the restricter


214


may be incorporated into the first seal assembly


44


without the need to change the geometry of any accommodating features of the downhole well tool


20


.




Those of ordinary skill in the art will recognize that any number of seals may be combined to form the first seal


44


without departing from the scope and spirit of the invention.




In a preferred embodiment, the first mating surface


204


of the first seal


202


is shaped substantially correspondingly with the second mating surface


210


of the second seal


208


. The first and second seals


202


,


208


are preferably chevron seals. It will be recognized by those of ordinary skill in the art that the first and second seals


202


,


208


need not be chevron seals, but can have virtually any radial cross-sectional shape, such as round, square, or a hybrid shape that is essentially a composite of different shapes.




In the preferred embodiment, the first seal


202


further includes a second mating surface


205


and a recess


207


in the second mating surface


205


. The first seal assembly


44


further includes a terminal adapter


216


having a first mating surface


218


and a recess


220


in the first mating surface


218


, the first mating surface


218


of the terminal adapter


216


being adjacent to the second mating surface


205


of the first seal


202


. A second thermal expansion restricter


222


is received simultaneously into the recesses


220


,


207


of the first and second mating surfaces


218


,


205


of the terminal adapter and first seal


216


,


202


, respectively. Preferably, the first mating surface


218


of the terminal adapter


216


is shaped substantially correspondingly with the second mating surface


205


of the first seal


202


. Those of ordinary skill in the art will recognize that adjacent surfaces of adjacent seal members need not be shaped substantially correspondingly, but may have gaps therebetween (not shown). Such gaps can be considered by the designer and the size of the restricter can be adjusted accordingly. Again, preferably, the thermal expansion restricter are metallic or filled composite and the first and second seals


202


,


208


are non-metallic chevron seals.




In a further preferred embodiment, the second seal


208


further includes a first mating surface


209


and a recess


211


in the first mating surface


209


. The first seal assembly


44


further includes a center adapter


224


having a second mating surface


226


and a recess


228


in the second mating surface


226


. The second mating surface


226


of the center adapter


224


is adjacent to the first mating surface


209


of the second seal


208


. A third thermal expansion restricter


230


is received simultaneously into the recesses


228


,


211


of the center adapter


224


and second seal


208


, respectively. Preferably the second mating surface


226


of the center adapter


224


is shaped substantially correspondingly with the first mating surface


209


of the second seal


208


. Again, preferably, the thermal expansion restricter are metallic or filled composite and the first and second seals


202


,


208


are non-metallic chevron seals.




In the preferred embodiment shown in

FIG. 4

, the first seal assembly


44


has a second, opposing set of seals


232


mirroring the first and second seals


202


,


208


. The individual seals of the opposing set of seals


232


are interlocked to each other and to the center adapter


224


and a second terminal adapter


234


by restricter


238


,


236


, and


240


respectively. It will be appreciated by those of ordinary skill in the art that the first seal assembly


44


need not have an opposing set of seals


232


, first and second terminal adapters


216


,


234


, or center adapter


224


, but may be limited to just a first seal


202


and second seal


208


and a first restricter


214


. Any number of additional seals and restricters (not shown) may be added. Moreover, in a further embodiment (not shown), the first seal assembly


44


could include first and second terminal adapters


216


,


234


and any number of individual seals interlocked by restricter. The critical requirement of the present invention for providing the thermal-growth-restriction feature is to interlock individual seals with restricter to prevent thermally-induced radial growth of the seals.




The second seal assembly


46


is generally identical to the first seal assembly


44


. Accordingly, the description of the first seal assembly


44


is equally applicable to the second seal assembly


46


.




It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. As stated above, the present invention is not limited in application to downhole well tools but may have application in any configuration wherein sealing between concentric tubular members is desired. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.



Claims
  • 1. A seal assembly comprising:a first seal having a first mating surface and a recess in the first mating surface; a second seal having a second mating surface and a recess in the second mating surface, the first mating surface of the first seal being in mating engagement with the second mating surface of the second seal; a first thermal expansion restricter received simultaneously into the recesses of the first and second mating surfaces of the first and second seals, respectively.
  • 2. The seal assembly according to claim 1, wherein the first mating surface of the first seal is shaped substantially correspondingly with the second mating surface of the second seal.
  • 3. The seal assembly according to claim 1, wherein the seals are chevron seals.
  • 4. The seal assembly according to claim 1, wherein the seals are non-metallic.
  • 5. The seal assembly according to claim 1, wherein the first thermal expansion restricter is metallic.
  • 6. The seal assembly according to claim 1, wherein the first thermal expansion restricter is filled composite.
  • 7. The seal assembly according to claim 1, wherein the first seal further includes a second mating surface and a recess in the second mating surface, the seal assembly further comprising:a terminal adapter having a first mating surface and a recess in the first mating surface, the first mating surface of the terminal adapter being adjacent to the second mating surface of the first seal; and a second thermal expansion restricter received simultaneously into the recesses of the first and second mating surfaces of the terminal adapter and first seal, respectively.
  • 8. The seal assembly according to claim 7, wherein the first mating surface of the terminal adapter is shaped substantially correspondingly with the second mating surface of the first seal.
  • 9. The seal assembly according to claim 7, wherein the seals are chevron seals.
  • 10. The seal assembly according to claim 7, wherein the seals are non-metallic.
  • 11. The seal assembly according to claim 7, wherein the thermal expansion restricters are metallic.
  • 12. The seal assembly according to claim 7, wherein the thermal expansion restricters are filled composite.
  • 13. The seal assembly according to claim 7, wherein the second seal further includes a first mating surface and a recess in the first mating surface, the seal assembly further comprising:a center adapter having a second mating surface and a recess in the second mating surface, the second mating surface of the center adapter being adjacent to the first mating surface of the second seal; and a third thermal expansion restricter received simultaneously into the recesses of the second and first mating surfaces of the center adapter and second seal, respectively.
  • 14. The seal assembly according to claim 13, wherein the second mating surface of the center adapter is shaped substantially correspondingly with the first mating surface of the second seal.
  • 15. The seal assembly according to claim 13, wherein the seals are chevron seals.
  • 16. The seal assembly according to claim 13, wherein the seals are non-metallic.
  • 17. The seal assembly according to claim 13, wherein the thermal expansion restricters are metallic.
  • 18. The seal assembly according to claim 13, wherein the thermal expansion restricters are filled composite.
  • 19. A downhole well tool of the type having an outer generally tubular member, an inner generally tubular member slidably and concentrically positioned within the outer tubular member, an outer tubular port perforating the outer tubular member, an inner tubular port perforating the inner tubular member, and first and second seal assemblies interposed in an annular region between the outer and inner tubular members, a sealed region being formed between the first and second seal assemblies when one of the outer tubular port and inner tubular port is not disposed between the first and second seal assemblies, the first and second seal assemblies each comprising:a first seal having a first mating surface and a recess in the first mating surface; a second seal having a second mating surface and a recess in the second mating surface, the first mating surface of the first seal being adjacent to the second mating surface of the second seal; a first thermal expansion restricter received simultaneously into the recesses of the first and second mating surfaces of the first and second seals, respectively.
  • 20. The seal assembly according to claim 19, wherein the first mating surface of the first seal is shaped substantially correspondingly with the second mating surface of the second seal.
  • 21. The seal assembly according to claim 19, wherein the seals are chevron seals.
  • 22. The seal assembly according to claim 19, wherein the seals are non-metallic.
  • 23. The seal assembly according to claim 19, wherein the first thermal expansion restricter is metallic.
  • 24. The seal assembly according to claim 19, wherein the first thermal expansion restricter is filled composite.
  • 25. The seal assembly according to claim 19, wherein the first seal further includes a second mating surface and a recess in the second mating surface, the seal assembly further comprising:a terminal adapter having a first mating surface and a recess in the first mating surface, the first mating surface of the terminal adapter being adjacent to the second mating surface of the first seal; and a second thermal expansion restricter received simultaneously into the recesses of the first and second mating surfaces of the terminal adapter and first seal, respectively.
  • 26. The seal assembly according to claim 25, wherein the first mating surface of the terminal adapter is shaped substantially correspondingly with the second mating surface of the first seal.
  • 27. The seal assembly according to claim 25, wherein the seals are chevron seals.
  • 28. The seal assembly according to claim 25, wherein the seals are non-metallic.
  • 29. The seal assembly according to claim 25, wherein the thermal expansion restricters are metallic.
  • 30. The seal assembly according to claim 25, wherein the thermal expansion restricters are filled composite.
  • 31. The seal assembly according to claim 25, wherein the second seal further includes a first mating surface and a recess in the first mating surface, the seal assembly further comprising:a center adapter having a second mating surface and a recess in the second mating surface, the second mating surface of the center adapter being adjacent to the first mating surface of the second seal; and a third thermal expansion restricter received simultaneously into the recesses of the second and first mating surfaces of the center adapter and second seal, respectively.
  • 32. The seal assembly according to claim 31, wherein the second mating surface of the center adapter is shaped substantially correspondingly with the first mating surface of the second seal.
  • 33. The seal assembly according to claim 31, wherein the seals are chevron seals.
  • 34. The seal assembly according to claim 31, wherein the seals are non-metallic.
  • 35. The seal assembly according to claim 31, wherein the thermal expansion restricters are metallic.
  • 36. The seal assembly according to claim 31, wherein the thermal expansion restricters are filled composite.
US Referenced Citations (26)
Number Name Date Kind
2264147 Dunlevy Nov 1941
2968516 Jarvis Jan 1961
3096660 Hausner Jul 1963
3342500 Kundson Sep 1967
3944306 Neilson Mar 1976
4040636 Albertson et al. Aug 1977
4066128 Davis et al. Jan 1978
4169604 Heathcott Oct 1979
4234197 Amancharla Nov 1980
4320803 Manderscheid Mar 1982
4512410 Forester Apr 1985
4527806 Ungchusri et al. Jul 1985
4576385 Ungchusri et al. Mar 1986
4612985 Rubbo et al. Sep 1986
4844411 Nelson Jul 1989
4848777 Zollo et al. Jul 1989
5052492 Torstensson Oct 1991
5156220 Forehand et al. Oct 1992
5263683 Wong Nov 1993
5271468 Streich et al. Dec 1993
5297805 Merkin et al. Mar 1994
5309993 Coon et al. May 1994
5316084 Murray et al. May 1994
5577739 Ciotola Nov 1996
5611547 Baugh et al. Mar 1997
5711372 Stokley Jan 1998