FLEXIBLE CRYOGENIC SEAL

Systems and methods are disclosed that include providing a valve suitable for maintaining a seal and preventing fluid flow through the valve at cryogenic temperatures. The valve includes a valve body, a ball selectively rotatable within the valve body, a seat having a seat insert at disposed within the valve body and configured to form a seal with the ball, and a seal disposed within a cavity formed between the valve body and the seat. The seal includes a seal body having a heel, an upper leg and a lower leg extending from the heel, and a cavity comprising a first cavity portion and a second cavity portion disposed between the upper leg and the lower leg. The first cavity portion includes at least one energizing element, and the second cavity portion may be free of an energizing element or include an energizing element.

BACKGROUND OF THE INVENTION

Valves are used to control the flow of fluids in a wide range of applications. Ball valves are typically used in applications where interruption of the flow of fluid through the ball valve is required. The interruption and establishment of fluid flow through the ball valve is accomplished via selective actuation of a ball within the ball valve. Seals within the ball valve may be used between ball valve components to control relative motion between such ball valve components to aid in controlling fluid flow through the ball valve. However, when a ball valve is subjected to extreme environmental conditions such as cryogenic temperatures, ball valve components may shrink, deform, or otherwise translate shift, thereby allowing leakage of the fluid through the ball valve. Accordingly, the industry continues to demand improvements in ball valve technology for such applications.

SUMMARY

Embodiments of the present invention relate in general to a valve having an annular seal that accommodates and/or compensates for hardware deformations in the valve that result from the valve being operated in or subjected to extreme environmental conditions such as at cryogenic temperatures. Embodiments of a seal may include a seal body, comprising: a heel; an upper leg and a lower leg each extending from the heel; and a cavity formed between the upper leg and the lower leg and comprising a first cavity portion and a second cavity portion; and an energizing element disposed within the first cavity portion. Embodiments of a valve may include a valve body; a ball selectively rotatable within the valve body; a seat having a seat insert disposed within the valve body and configured to form a seal with the ball; and a seal disposed within a cavity formed between the valve body and the seat, wherein the seal comprises: a seal body, comprising: a heel; an upper leg and a lower leg extending from the heel; and a cavity comprising a first cavity portion and a second cavity portion disposed between the upper leg and the lower leg; and an energizing element disposed within the first cavity portion.

DETAILED DESCRIPTION

FIG. 1shows a partial cross-sectional view of a valve100according to an embodiment of the disclosure. In some embodiments, valve100may comprise a ball valve. However, in other embodiments, valve100may comprise any other suitable valve. Valve100may generally comprise a valve body102having a longitudinal axis104along a flow path through the valve100and a ball106selectively rotatable within the valve body102to selectively allow fluid flow along the flow path and through the valve100. Valve100may also comprise a seat108having a seat insert112that may generally be designed to prevent leakage of a fluid through a leakage path when the ball106is selectively rotated to prevent fluid flow along the flow path and through the valve100. In some embodiments, a cavity110may be formed between the valve body102and the seat108. Additionally, in some embodiments, the valve100may also comprise one or more springs114configured to bias the seat108away from the valve body102and towards the ball106to selectively maintain a fluid tight seal between the seat insert112and the ball106. Furthermore, in some embodiments, the valve100may also comprise one or more seals200.

FIG. 2shows a partial cross-sectional view of a seal200according to an embodiment of the disclosure. Seal200may generally be configured to accommodate and/or compensate for hardware deformations in the valve100that result when the valve100is operated in extreme environmental conditions such as at cryogenic temperatures. Seal200may generally comprise a heel202, an upper leg204extending from the heel202, a lower leg206extending from the heel202, a cavity208formed between the upper leg204and the lower leg206, and an energizing element210. The heel202may generally comprise a base and/or vertical structure of the seal200. In some embodiments, the heel202may form an inner diameter of the seal200. In other embodiments, the heel202may form an outer diameter of the seal200. Accordingly, in some embodiments, the heel202may seat against the valve body102of the valve100. In other embodiments, the heel202may seat against the seat108of the valve100. In alternative embodiments, the heel202may seat against other components of the valve100depending on the configuration of the valve100.

The upper leg204may generally extend from an upper end of the heel202. In some embodiments, the upper leg204may extend orthogonally from the upper end of the heel202. In other embodiments, the upper leg204may extend at an acute or obtuse angle from the upper end of the heel202(e.g., 5 degrees, 10 degrees, etc.). The upper leg204may generally comprise an outer upper surface212that extends from the heel202, a radial transition214, and an outer upper contact surface216. In some embodiments, the radial transition214may comprise multiple radial curves that join the outer upper surface212and the outer upper contact surface216. In some embodiments, the outer upper surface212and the outer upper contact surface216may be substantially parallel. In some embodiments, the outer upper contact surface216may comprise a larger vertical height from a center218of the energizing element210than does the outer upper surface212from the center218of the energizing element210. Thus, the seal200may comprise a larger overall vertical height measured at the outer upper contact surface216as compared the vertical height measured at the outer upper surface212. It will further be appreciated that in some embodiments, the outer upper contact surface216may remain in contact with the valve body102, the seat108, and/or another component of the valve100during operation to stabilize the components of the valve100and accommodate and/or compensate for hardware deformations in the valve100that result when the valve100is operated. Further, in some embodiments, the upper leg204may comprise a bevel220at an end of the outer upper contact surface216. Still further, in some embodiments, the upper leg204may comprise an end surface222extending from the bevel220. In some embodiments, the end surface222may angle inwards towards the center218of the energizing element210. However, in other embodiments, the end surface222may be substantially vertical.

The lower leg206may generally extend from a lower end of the heel202. In some embodiments, the lower leg206may extend orthogonally from the lower end of the heel202. In other embodiments, the lower leg206may extend at an acute or obtuse angle from the lower end of the heel202(e.g., 5 degrees, 10 degrees, etc.). The lower leg206may generally comprise an outer lower surface224that extends from the heel202, a radial transition226, and an outer lower contact surface228. In some embodiments, the radial transition226may comprise multiple radial curves that join the outer lower surface224and the outer lower contact surface228. In some embodiments, the outer lower surface224and the outer lower contact surface228may be substantially parallel. In some embodiments, the outer lower contact surface228may comprise a larger vertical height from the center218of the energizing element210than does the outer lower surface224from the center218of the energizing element210. Thus, the seal200may comprise a larger overall vertical height measured at the outer lower contact surface228as compared the vertical height measured at the outer lower surface224. It will further be appreciated that in some embodiments, the outer lower contact surface228may remain in contact with the valve body102, the seat108, and/or another component of the valve100during operation to stabilize the components of the valve100and accommodate and/or compensate for hardware deformations in the valve100that result when the valve100is operated. Further, in some embodiments, the lower leg206may comprise a bevel230at an end of the outer lower contact surface228. Still further, in some embodiments, the lower leg206may comprise an end surface232extending from the bevel230. In some embodiments, the end surface232may angle inwards towards the center218of the energizing element210. However, in other embodiments, the end surface232may be substantially vertical.

The cavity208may generally be formed between the upper leg204and the lower leg206and comprise a first cavity portion234and a second cavity portion236. The first cavity portion234may generally comprise an opening238defined between an upper opening surface240that extends from the upper end surface222of the upper leg204and a lower opening surface that extends from the lower end surface232of the lower leg206. In some embodiments, the opening surfaces240,242may be substantially horizontal and/or parallel to each other. However, in other embodiments, the opening surfaces240,242may comprise any other non-horizontal orientation and/or may comprise different dimensions. The first cavity portion234may also comprise an upper curved surface244extending from the upper opening surface240and a lower curved surface246extending from the lower opening surface242. The curved surfaces244,246may extend from the opening surfaces240,242, respectively, and truncate at and be open to the second cavity portion236. In some embodiments, the curved surfaces244,246may be symmetrical about a horizontal centerline that extends through the center218of the energizing element210. Thus, it will be appreciated that the curved surfaces244,246may comprise substantially equal radii and/or substantially equal curve lengths. Furthermore, the first cavity portion234may be configured to receive the energizing element210and capture the energizing element210between the upper curved surface244and the lower curved surface246. Thus, it will be appreciated that the curved surfaces244,246may comprise a larger radius than that of the energizing element210.

The second cavity portion236may generally be formed between the first cavity portion234and the heel202. The second cavity portion236may generally comprise an upper surface248, an opposing lower surface250, and a vertical wall252disposed between the upper surface248and the lower surface250and opposite the opening238of the first cavity portion234. While the first cavity portion234comprises the energizing element210, the second cavity portion236may be free of an energizing element210. In alternative embodiments, the second cavity portion236may comprise an energizing element210, a spring, or any combination thereof, and the surfaces248,250may comprise a profile substantially similar to that of the curved surfaces244,246. The upper surface248may extend towards the heel202from the upper curved surface244to the vertical wall252. The lower surface250may extend towards the heel202from the lower curved surface246to the vertical wall252. In some embodiments, the upper surface248and the lower surface250may comprise substantially equal lengths. In some embodiments, the upper surface248and the lower surface250may be substantially parallel. However, in other embodiments, the upper surface248and the lower surface250may be angled or curved with respect to the horizontal centerline that extends through the center218of the energizing element210. Additionally, in some embodiments, the vertical wall252may be substantially parallel to the heel202of the seal200and orthogonal to each of the upper surface248and the lower surface250. However, in other embodiments, the vertical wall252may comprise any other profile (e.g., including one or more non-vertical elements). Thus, it will be appreciated that in some embodiments, the second cavity portion236may comprise a substantially rectangular or square cross-sectional profile. Further, in some embodiments, a chamfer and/or radius may be present between the vertical wall252and each of the upper surface248and the lower surface250. However, in other embodiments, the second cavity portion236may comprise any other shaped profile (e.g., oval, rounded having similar or dissimilar radii, trapezoidal, symmetrical, non-symmetrical, or any combination of various features and/or profiles).

The energizing element210may generally comprise a spring and be disposed within the first cavity portion234between the upper curved surface244and the lower curved surface246. The energizing element210may be configured to bias the upper leg204and the lower leg206away from each other to maintain contact between the outer upper contact surface216and the valve body102, the seat108, and/or another component of the valve100and the outer lower contact surface228and the valve body102, the seat108, and/or another component of the valve100. Accordingly, the energizing element may conform to one or more curved surfaces244,246in response to deformation or misalignment in the valve100caused by operation of the valve100. In some embodiments, the energizing element210may comprise a circular profile. However, in other embodiments, the spring may comprise another profile, such as an oval-shaped profile, a U-shaped profile, a V-shaped profile, or any other shaped profile. In some embodiments, the energizing element210may comprise a single layer of material. However, in other embodiments, the energizing element210may comprise multiple layers or plies of material. Suitable materials for the energizing element210may include, for example, titanium, stainless steel, steel, Inconel®, Elgiloy®, Hastelloy®, other resilient metallic materials, or any combination thereof. Furthermore, the seal body (comprising all components of the seal200without the energizing element210) may be formed from PTFE, a fluoropolymer, a perfluoropolymer, PTFE, TFM, PVF, PVDF, PCTFE, PFA, FEP, ETFE, ECTFE, PCTFE, a polyarylketone such as PEEK, PEK, or PEKK, a polysulfone such as PPS, PPSU, PSU, PPE, or PPO, aromatic polyamides such as PPA, thermoplastic polyimides such as PEI or TPI, or any combination thereof.

Still referring toFIG. 2, the seal may generally be substantially symmetrical about the horizontal centerline that extends through the center218of the energizing element210. The seal200may also comprise a larger overall height as measured between the upper contact surface216and the lower contact surface228as compared to the overall height measured between the upper surface212and the lower surface224. It will be appreciated that the overall height of the first cavity portion234as measured between the upper curved surface244and the lower curved surface246may be larger than the overall height of the second cavity portion236as measured between the upper surface248and the lower surface250. Further, the overall height of the opening238as measured between the upper opening surface240and the lower opening surface242may be larger than the overall height of the second cavity portion236as measured between the upper surface248and the lower surface250.

The second cavity portion236may comprise a horizontal length or depth as measured by the horizontal length of the upper surface248and/or the lower surface250of the second cavity portion236. The depth of the second cavity portion236may comprise a percentage of the depth of the first cavity portion234as measured along the horizontal centerline that extends through the center218of the energizing element210. In some embodiments, the depth of the second cavity portion236may be at least 25%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 90%, at least 95%, or at least 100% of the depth of the first cavity portion234. In some embodiments, the depth of the second cavity portion236may be not greater than 200%, not greater than 150%, not greater than 125%, or not greater than 100% of the depth of the first cavity portion234. Further, it will be appreciated that the depth of the second cavity portion236may be between any of these minimum and maximum values, such as at least 25% and not greater than 200% of the depth of the first cavity portion234.

The depth of the second cavity portion236may also comprise a percentage of the overall length of the seal200as measured along the horizontal centerline that extends through the center218of the energizing element210. In some embodiments, the depth of the second cavity portion236may be at least 5%, at least 10%, at least 15%, at least 20%, at least 30%, at least 35%, or at least 40% of the overall length of the seal200. In some embodiments, the depth of the second cavity portion236may be not greater than 80%, not greater than 75%, not greater than 70%, not greater than 65%, not greater than 60%, not greater than 55%, not greater than 50%, not greater than 45%, or not greater than 40% of the overall length of the seal200. Further, it will be appreciated that the depth of the second cavity portion236may be between any of these minimum and maximum values, such as at least 5% and not greater than 80% of the overall length of the seal200.

FIG. 3shows a graph of the contact pressures (contact pressure profile) of embodiments of the seal200in an aligned condition, a 0.2 mm misaligned condition, and a 0.3 mm misaligned condition. As shown, it can be seen that the major impact of the misalignment is on the maximal load of each peak. The main difference between aligned and misaligned is that, during pressurization, the two peaks are merging (i.e. the sealing path becomes continuous) for a misaligned condition. The lower contact pressure is then compensated by a longer contact length. Thus, as a result, the seal200increases contact pressure between the contact surfaces216,228of the seal200and the components of the valve100. In some embodiments, as compared to a traditional seal without a second cavity portion236, seal200having a second cavity portion236may increase a contact pressure at each of the contact surfaces216,228and/or sealing force between the seal200and components of the valve100. In some embodiments, the seal200may increase the contact pressure and/or the sealing force by at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 75%, at least 95%, at least 100%, at least 125%, or at least 150%. In some embodiments, the seal200may increase the contact pressure and/or the sealing force by not greater than 500%, not greater than 400%, not greater than 300%, not greater than 200%, or not greater than 100%. Further, it will be appreciated that the seal200may increase the contact pressure and/or the sealing force by between any of these minimum and maximum values, such as at least 5% and not greater than 500%.

FIG. 4Ashows the leak performance data for multiple tests of an embodiment of a seal200for the aligned condition.FIG. 4Bshows the leak performance data for multiple tests of an embodiment of a seal200for the 0.2 mm misaligned condition.FIG. 4Cshows the leak performance data for multiple tests of an embodiment of a seal200for the 0.3 mm misaligned condition. As shown inFIG. 4A, it can be seen that the performance under aligned conditions is relatively constant and passes the 25% limit of the Shell300Specification. As shown inFIG. 4B, it can be seen that the performance in the 0.2 mm misaligned condition passes the 25% limit of the Shell300Specification. As shown inFIG. 4C, it can be seen that the performance in the 0.3 mm misaligned condition passes the 25% limit of the Shell300Specification.

Embodiments of the valve100and/or the seal200may include, inter alia, one or more of the following items:

Embodiment 1. A seal, comprising: a seal body, comprising: a heel; an upper leg and a lower leg each extending from the heel; and a cavity formed between the upper leg and the lower leg and comprising a first cavity portion and a second cavity portion; and an energizing element disposed within the first cavity portion.

Embodiment 2. The seal of embodiment 1, wherein the upper leg comprises an upper surface extending from the heel and an upper contact surface, and wherein the lower leg comprises a lower surface extending from the heel and a lower contact surface.

Embodiment 3. The seal of embodiment 2, wherein each of the upper leg and the lower leg extend orthogonally from the heel.

Embodiment 4. The seal of any of embodiments 2 to 3, wherein the upper contact surface and the lower contact surface are substantially parallel.

Embodiment 5. The seal of any of embodiments 2 to 4, wherein the seal comprises a larger overall height measured between the upper contact surface and the lower contact surface as compared to the overall height measured between the upper surface and the lower surface.

Embodiment 6. The seal of any of embodiments 1 to 5, wherein the first cavity portion comprises an opening.

Embodiment 7. The seal of embodiment 6, wherein the opening is defined between an upper opening surface of the upper leg and a lower opening surface of the lower leg.

Embodiment 8. The seal of embodiment 7, wherein the first cavity portion comprises an upper curved surface extending from the upper opening surface to the second cavity portion and a lower curved surface extending from the lower opening surface to the second cavity portion.

Embodiment 9. The seal of embodiment 8, wherein the upper curved surface and the lower curved surface are symmetrical about a horizontal centerline that extends through the center of the seal.

Embodiment 10. The seal of any of embodiments 8 to 9, wherein the upper curved surface and the lower curved surface comprise substantially equal radii.

Embodiment 11. The seal of any of embodiments 8 to 10, wherein the upper curved surface and the lower curved surface comprise substantially equal curve lengths.

Embodiment 12. The seal of any of embodiments 8 to 11, wherein the first cavity portion is configured to receive the energizing element and capture the energizing element between the upper curved surface and the lower curved surface.

Embodiment 13. The seal of embodiment 12, wherein the upper curved surface and the lower curved surface comprise a larger radius than that of the energizing element.

Embodiment 14. The seal of any of embodiments 1 to 13, wherein the energizing element is formed from titanium, stainless steel, steel, Inconel®, Elgiloy®, Hastelloy®, other resilient metallic materials, or any combination thereof.

Embodiment 15. The seal of any of embodiments 1 to 14, wherein the second cavity portion is formed between the first cavity portion and the heel.

Embodiment 16. The seal of any of embodiments 8 to 15, wherein the second cavity portion comprises an upper surface extending towards the heel from the upper curved surface to the vertical wall, an opposing lower surface extending towards the heel from the lower curved surface to the vertical wall, and a vertical wall disposed between the upper surface and the lower surface and opposite the opening of the first cavity portion.

Embodiment 17. The seal of embodiment 16, wherein the vertical wall is substantially parallel to the heel.

Embodiment 18. The seal of embodiment 17, wherein the upper surface and the lower surface are substantially parallel.

Embodiment 19. The seal of embodiment 18, wherein the vertical wall is substantially orthogonal to each of the upper surface and the lower surface.

Embodiment 20. The seal of any of embodiments 1 to 19, wherein the second cavity portion is free of an energizing element.

Embodiment 21. The seal of any of embodiments 16 to 20, wherein an overall height of the opening as measured between the upper opening surface and the lower opening surface is larger than the overall height of the second cavity portion as measured between the upper surface and the lower surface.

Embodiment 22. The seal of any of embodiments 1 to 21, wherein a depth of the second cavity portion is at least 25%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 90%, at least 95%, or at least 100% of the depth of the first cavity portion.

Embodiment 23. The seal of embodiment 22, wherein the depth of the second cavity portion is not greater than 200%, not greater than 150%, not greater than 125%, or not greater than 100% of the depth of the first cavity portion.

Embodiment 24. The seal of any of embodiments 1 to 23, wherein the depth of the second cavity portion is at least 5%, at least 10%, at least 15%, at least 20%, at least 30%, at least 35%, or at least 40% of the overall length of the seal.

Embodiment 25. The seal of embodiment 24, wherein the depth of the second cavity portion is not greater than 80%, not greater than 75%, not greater than 70%, not greater than 65%, not greater than 60%, not greater than 55%, not greater than 50%, not greater than 45%, or not greater than 40% of the length of the overall length of the seal.

Embodiment 26. The seal of any of embodiments 1 to 25, wherein as compared to a traditional seal without a second cavity portion, the seal increases a contact pressure at each of the upper contact surface and the lower contact surface by at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 75%, at least 95%, at least 100%, at least 125%, or at least 150%.

Embodiment 27. The seal of embodiment 26, wherein the seal increases a contact pressure at each of the upper contact surface and the lower contact surface by not greater than 500%, not greater than 400%, not greater than 300%, not greater than 200%, or not greater than 100%.

Embodiment 28. The seal of any of embodiments 1 to 27, wherein the seal conforms to a 25% limit of a Shell300Specification for leakage in each of an aligned condition and a misaligned condition.

Embodiment 29. A valve, comprising: a valve body; a ball selectively rotatable within the valve body; a seat having a seat insert at disposed within the valve body and configured to form a seal with the ball; and a seal disposed within a cavity formed between the valve body and the seat, wherein the seal comprises: a seal body, comprising: a heel; an upper leg and a lower leg extending from the heel; and a cavity comprising a first cavity portion and a second cavity portion disposed between the upper leg and the lower leg; and an energizing element disposed within the first cavity portion.

Embodiment 30. The valve of embodiment 29, wherein the upper leg comprises an upper surface extending from the heel and an upper contact surface, and wherein the lower leg comprises a lower surface extending from the heel and a lower contact surface.

Embodiment 31. The valve of embodiment 30, wherein each of the upper leg and the lower leg extend orthogonally from the heel.

Embodiment 32. The valve of any of embodiments 30 to 31, wherein the upper contact surface and the lower contact surface are substantially parallel.

Embodiment 33. The valve of any of embodiments 30 to 32, wherein the seal comprises a larger overall height measured between the upper contact surface and the lower contact surface as compared to the overall height measured between the upper surface and the lower surface.

Embodiment 34. The valve of any of embodiments 29 to 33, wherein the first cavity portion comprises an opening.

Embodiment 35. The valve of embodiment 34, wherein the opening is defined between an upper opening surface of the upper leg and a lower opening surface of the lower leg.

Embodiment 36. The valve of embodiment 35, wherein the first cavity portion comprises an upper curved surface extending from the upper opening surface to the second cavity portion and a lower curved surface extending from the lower opening surface to the second cavity portion.

Embodiment 37. The valve of embodiment 36, wherein the upper curved surface and the lower curved surface are symmetrical about a horizontal centerline that extends through the center of the seal.

Embodiment 38. The valve of any of embodiments 36 to 37, wherein the upper curved surface and the lower curved surface comprise substantially equal radii.

Embodiment 39. The valve of any of embodiments 36 to 38, wherein the upper curved surface and the lower curved surface comprise substantially equal curve lengths.

Embodiment 40. The valve of any of embodiments 36 to 39, wherein the first cavity portion is configured to receive the energizing element and capture the energizing element between the upper curved surface and the lower curved surface.

Embodiment 41. The valve of embodiment 40, wherein the upper curved surface and the lower curved surface comprise a larger radius than that of the energizing element.

Embodiment 42. The valve of embodiment 41, wherein the energizing element confirms to the upper curved surface and the lower curved surface under deformation, misalignment, or pressurization in the valve.

Embodiment 43. The valve of any of embodiments 29 to 42, wherein the energizing element is formed from titanium, stainless steel, steel, Inconel®, Elgiloy®, Hastelloy®, other resilient metallic materials, or any combination thereof.

Embodiment 44. The valve of any of embodiments 29 to 43, wherein the second cavity portion is formed between the first cavity portion and the heel.

Embodiment 45. The valve of any of embodiments 36 to 44, wherein the second cavity portion comprises an upper surface extending towards the heel from the upper curved surface to the vertical wall, an opposing lower surface extending towards the heel from the lower curved surface to the vertical wall, and a vertical wall disposed between the upper surface and the lower surface and opposite the opening of the first cavity portion.

Embodiment 46. The valve of embodiment 45, wherein the vertical wall is substantially parallel to the heel.

Embodiment 47. The valve of embodiment 46, wherein the upper surface and the lower surface are substantially parallel.

Embodiment 48. The valve of embodiment 47, wherein the vertical wall is substantially orthogonal to each of the upper surface and the lower surface.

Embodiment 49. The valve of any of embodiments 29 to 48, wherein the second cavity portion is free of an energizing element.

Embodiment 50. The valve of any of embodiments 47 to 49, wherein the upper surface and the lower surface angle inward under deformation, misalignment, or pressurization in the valve.

Embodiment 51. The valve of any of embodiments 45 to 50, wherein an overall height of the opening as measured between the upper opening surface and the lower opening surface is larger than the overall height of the second cavity portion as measured between the upper surface and the lower surface.

Embodiment 52. The valve of any of embodiments 29 to 51, wherein a depth of the second cavity portion is at least 25%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 90%, at least 95%, or at least 100% of the depth of the first cavity portion.

Embodiment 53. The valve of embodiment 52, wherein the depth of the second cavity portion is not greater than 200%, not greater than 150%, not greater than 125%, or not greater than 100% of the depth of the first cavity portion.

Embodiment 54. The valve of any of embodiments 29 to 53, wherein the depth of the second cavity portion is at least 5%, at least 10%, at least 15%, at least 20%, at least 30%, at least 35%, or at least 40% of the overall length of the seal.

Embodiment 55. The valve of embodiment 54, wherein the depth of the second cavity portion is not greater than 80%, not greater than 75%, not greater than 70%, not greater than 65%, not greater than 60%, not greater than 55%, not greater than 50%, not greater than 45%, or not greater than 40% of the length of the overall length of the seal.

Embodiment 56. The valve of any of embodiments 29 to 55, wherein as compared to a traditional seal without a second cavity portion, the seal increases a contact pressure at each of the upper contact surface and the lower contact surface by at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 75%, at least 95%, at least 100%, at least 125%, or at least 150%.

Embodiment 57. The valve of embodiment 56, wherein the seal increases a contact pressure at each of the upper contact surface and the lower contact surface by not greater than 500%, not greater than 400%, not greater than 300%, not greater than 200%, or not greater than 100%.

Embodiment 58. The valve of any of embodiments 29 to 57, wherein the seal conforms to a 25% limit of a Shell300Specification for leakage in each of an aligned condition and a misaligned condition.

Embodiment 59. The seal of any of embodiments 1 to 28 or the valve of any of embodiments 29 to 58, wherein the seal body is formed from PTFE, a fluoropolymer, a perfluoropolymer, PTFE, TFM, PVF, PVDF, PCTFE, PFA, FEP, ETFE, ECTFE, PCTFE, a polyarylketone such as PEEK, PEK, or PEKK, a polysulfone such as PPS, PPSU, PSU, PPE, or PPO, aromatic polyamides such as PPA, thermoplastic polyimides such as PEI or TPI, or any combination thereof.

Embodiment 60. The seal of any of embodiments 1 to 28 and 59 or the valve of any of embodiments 29 to 59, wherein the upper surface and the lower surface are substantially curved.

Embodiment 61. The seal or the valve of embodiment 60, wherein the second cavity comprises an energizing element.

This written description uses examples to disclose the embodiments, including the best mode, and also to enable those of ordinary skill in the art to make and use the invention. The patentable scope is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.