Patent Description:
Ball valves typically require the use of seat seals to preserve effective valve integrity when pressurized. Single piston effect seat seals operate unidirectionally while double piston effect seals operate bidirectionally.

Ball valves are used in a wide variety of industries including transportation, transmission and storage of fluids, gas processing, and industrial manufacturing. <CIT> is concerned with a sealing assembly including a sealing component, a first backup ring component, and a second backup ring component. Industries utilizing ball valves continue to demand improvements in seat seal performance, particularly when operating in extreme environmental conditions like cryogenic temperatures, such as below -<NUM>.

Embodiments are illustrated by way of example and are not intended to be limited in the accompanying figures.

The following description in combination with the figures is provided to assist in understanding the teachings disclosed herein. The following discussion will focus on specific implementations and embodiments of the teachings. This focus is provided to assist in describing the teachings and should not be interpreted as a limitation on the scope or applicability of the teachings. However, other embodiments can be used based on the teachings as disclosed in this application.

The terms "generally," "substantially," "approximately," and the like are intended to cover a range of deviations from the given value. In a particular embodiment, the terms "generally," "substantially," "approximately," and the like refer to deviations in either direction of the value within <NUM>% of the value, within <NUM>% of the value, within <NUM>% of the value, within <NUM>% of the value, within <NUM>% of the value, within <NUM>% of the value, within <NUM>% of the value, within <NUM>% of the value, within <NUM>% of the value, or within <NUM>% of the value.

The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent not described herein, many details regarding specific materials and processing acts are conventional and may be found in textbooks and other sources within the seal arts.

A ball valve in accordance with an embodiment can include a seal forming a double piston effect seal in cryogenic conditions. In a particular embodiment, the seal can form a double piston effect seal at both an upstream seat position and a downstream seat position. The ball valve can include a trunnion mounted ball valve, a floating ball valve, or a rising stem ball valve. While the ball valve can be two-way, three-way, four-way, or more-way depending on the use, description herein is made with respect to a two-way ball valve for simplicity.

In an embodiment, the ball valve can include an upstream seat seal, a downstream seat seal, or a combination thereof. In a particular embodiment, the upstream seat seal and downstream seat seal can be symmetrical, such as reflectively symmetrical, translationally symmetrical, or rotationally symmetrical. In a more particular embodiment, the upstream seat seal and downstream seat seal can be identical. In an embodiment, the ball valve can further include a rotatable bore that can be moved a quarter turn to selectively close the ball valve and restrict fluid movement.

According to the invention, the seal (either or both the upstream and downstream seal(s)) includes a resilient ring defining an engagement feature and a first polymer ring disposed adjacent to a first axial end of the resilient ring and coupled with the engagement feature. A second polymer ring is disposed adjacent to a second axial end of the resilient ring and coupled with the engagement feature. In a particular embodiment, the first and second polymer rings can be coupled with the same engagement feature.

The engagement feature can be adapted to selectively couple with the first and second polymer rings. In an embodiment, the engagement feature includes at least one of a notch, a ridge, a cutout, a castellation, a tine, or any combination thereof. In an embodiment, the engagement feature can be disposed along an outer diameter of the resilient ring. In an embodiment, the engagement feature defines a first axial end and a second axial end. The first polymer ring can be coupled with the resilient ring adjacent to the first axial end and the second polymer ring can be coupled with the resilient ring adjacent to the second axial end. The first polymer ring contacts the second polymer ring. The first polymer ring contacts the second polymer ring at an axial location corresponding with the engagement feature.

In an embodiment, the first polymer ring can include a first corresponding engagement feature adapted to engage with the engagement feature of the resilient ring. In another embodiment, the second polymer ring can include a second corresponding engagement feature adapted to engage with the engagement feature of the resilient ring. In an embodiment, the first corresponding engagement feature includes a barb adapted to engage with the engagement feature of the resilient ring. In another embodiment, the second corresponding engagement feature includes a barb adapted to engage with the engagement feature of the resilient ring.

In an embodiment, the first and second corresponding engagement features can have at least one of a same or generally same cross-sectional shape, a same or generally same cross-sectional area, a same or generally same cross-sectional dimension, or any combination thereof.

The first polymer ring can include a body defining an energized zone coupled with the first corresponding engagement feature. The second polymer ring can also include a body defining an energized zone coupled with the second corresponding engagement feature. In an embodiment, the energized zone of at least one of the first and second polymer rings can include at least two energizing elements, such as at least two springs disposed at least partially within the body of the polymer ring. In another embodiment, the energized zone of at least one of the first and second polymer rings can have a cross-sectional shape forming a capital E.

In an embodiment, the at least two energizing elements can be disposed along a straight line, when viewed in cross section. The at least two energizing elements can include a first element and a second element, such as a first spring and a second spring. The first energizing element can be disposed radially inside of the second energizing element. In an embodiment, the second energizing element has an energizing capacity greater than the energizing capacity of the first energizing element. For example, in an embodiment, the second spring can have a diameter greater than a diameter of the first spring. Moreover, the second spring can have a higher spring constant as compared to the first spring.

In an embodiment, the resilient ring can include an inner diameter, an outer diameter, a first axial end, and a second axial end. An edge between at least one of the first and second axial ends and the outer diameter can include a chamfer. In an embodiment, the chamfer has an angle of at least <NUM> degrees relative to a central axis of the seal, at least <NUM> degrees, at least <NUM> degrees, at least <NUM> degrees, at least <NUM> degrees, at least <NUM> degrees, at least <NUM> degrees, or at least <NUM> degrees. In a particular embodiment, the chamfer has an angle of approximately <NUM> degrees relative to a central axis of the seal.

In an embodiment, at least one of the first and second polymer rings includes a thermoplastic. In another embodiment, the first and second polymer rings are part of a same element (i.e., they are part of a single polymer element).

Referring to <FIG> a ball valve <NUM> can generally include a central bore <NUM> and a valve stem <NUM> with an exterior mounting flange <NUM> for supporting a hydraulic motor or manual interface for rotating the valve stem <NUM>. Flow lines 110A and 110B, with axes coincident with the axis of the central bore <NUM> are coupled with the ball valve <NUM> at locations 112A and 112B, respectively. In an embodiment, coupling the flow lines 110A and 110B to the ball valve can make an integral body. The flow tubes 110A and 110B can have flanged portions <NUM> at their ends for connection with similar attaching flanges on the tubulars in the flow patch in which the ball valve <NUM> is connected.

In an embodiment, the valve stem <NUM> is journaled in a gland bushing <NUM> and bushing <NUM>. A seal <NUM> can be provided between the gland bushing <NUM> and bushing <NUM>. The gland bushing <NUM> can be removably mounted in the valve stem <NUM> by a snap ring <NUM> received in an annular groove in the outer end of the valve stem <NUM>. The gland bushing <NUM> can further abut a washer <NUM> which bears against the end of the gland bushing <NUM>. The lower end of the bushing <NUM> can abut a shoulder <NUM> on the end of the valve stem <NUM> and the shouldered end of the stem can fit into a socket <NUM> in the ball <NUM>. In an embodiment, the stem can be keyed to the ball <NUM> by pins <NUM> to prevent relative movement between the ball <NUM> and the stem <NUM>.

Opposite the socket <NUM> can be a socket <NUM> in the ball <NUM> which has a bearing bushing <NUM> in which a trunnion is journaled. The trunnion can extend through the central bore <NUM> and a cover plate <NUM> can be secured by threaded fasteners <NUM> on the tube over the outer end of the trunnion. A seal <NUM> can be provided in the trunnion to provide a seal between the trunnion and the opening in the tube in which it fits.

The flange portions <NUM> can have spherical seating surfaces <NUM> and <NUM> which generally conform to the outer surface of the ball <NUM> and internal shoulders <NUM> of the central bore <NUM> abut the flanged portions <NUM> to leave a slight clearance between the ball and the surfaces <NUM> and <NUM>. Seats <NUM> and <NUM> can be disposed between the ball <NUM> and surrounding the sockets <NUM> and <NUM>.

Referring to <FIG>, at least one of the seats <NUM> and <NUM> can include a seat body <NUM>, an insert <NUM> adapted to contact the ball <NUM>, and a seal <NUM>. In a particular embodiment, the seat body <NUM> can include a resilient material, such as a metal or an alloy. The insert <NUM> can extend between the seat body <NUM> and contact the ball <NUM>. In an embodiment, the insert <NUM> can include a polymeric material. In another embodiment, the insert <NUM> can include a metal or an alloy. A biasing element, such as a spring (not illustrated) can bias the seat body <NUM> relative to the flow tubes 110A and 110B. In an embodiment, the biasing element can bias the seat body <NUM> in a direction generally toward the ball <NUM>.

<FIG> includes a cross-sectional view of a seal <NUM> in accordance with an embodiment. While the following description is made with respect to the seal <NUM>, it should be understood that the seal <NUM> can have any similar or different features as compared with the seal <NUM>. In a particular embodiment, the seal <NUM> is disposed upstream of the ball <NUM> and the seal <NUM> is disposed downstream of the ball <NUM>. In certain instances, the seals <NUM> and <NUM> can define rings.

In an embodiment, the seal <NUM> can be adapted for use in cryogenic temperature applications. More particularly the seal <NUM> can be adapted for use at temperatures below - <NUM>, below -<NUM>, below -<NUM>, or below -<NUM>. In certain instances the seal <NUM> can be a double piston effect seal. In other instances, the seal <NUM> can be a single piston effect seal.

The seal <NUM> can include a resilient ring <NUM> having a generally annular structure defining a central axis. The resilient ring <NUM> can be formed from a resilient material, such as a metal, alloy, or resilient polymer. In a particular embodiment, the resilient ring <NUM> can include steel. In a more particular embodiment, the resilient ring <NUM> can include <NUM> ST steel.

The resilient ring <NUM> can define an inner diameter corresponding with an inner surface <NUM> of the resilient ring <NUM>, an outer diameter corresponding with an outer surface <NUM> of the resilient ring <NUM>, a first axial end <NUM>, and a second axial end <NUM> opposite the first axial end <NUM>.

In an embodiment, the resilient ring <NUM> can include a chamfered edge <NUM>. In certain instances, the chamfered edge <NUM> can extend between the outer surface <NUM> and the first axial end <NUM>. In another instance, the chamfered edge <NUM> can extend between the outer surface <NUM> and the second axial end <NUM>. In yet a further instance, the resilient ring <NUM> can include a chamfered edge <NUM> between the outer surface <NUM> and the first axial end <NUM> and a chamfered edge <NUM> between the outer surface <NUM> and the second axial end <NUM>. In an embodiment, the chamfered edge <NUM> can have an angle of at least <NUM> degrees as measured relative to a central axis of the seal <NUM>. In a more particular embodiment, the chamfered edge <NUM> can have an angle of at least <NUM> degrees, at least <NUM> degrees, at least <NUM> degrees, at least <NUM> degrees, at least <NUM> degrees, at least <NUM> degrees, or at least <NUM> degrees. In a particular embodiment, the chamfered edge <NUM> can have an angle of approximately <NUM> degrees as measured relative to the central axis of the seal <NUM>.

In an embodiment, the resilient ring <NUM> can define an engagement feature <NUM>. In a particular embodiment, the engagement feature <NUM> can be disposed along a surface of the resilient ring <NUM>. More particularly, the engagement feature <NUM> can be disposed along the outer surface <NUM> of the resilient ring <NUM>. In the illustrated embodiment, the engagement feature <NUM> is shown in an axially-centered position, equidistance from the first and second axial ends <NUM> and <NUM>. In another embodiment, the engagement feature <NUM> can be disposed closer to one of the first and second axial ends <NUM> or <NUM> as compared to the other of the first and second axial ends <NUM> or <NUM>.

In an embodiment, the engagement feature <NUM> can include one or more notches extending from the outer surface <NUM> of the resilient ring <NUM>. In a more particular embodiment, the engagement feature <NUM> can include a castellated feature(s) extending from the outer surface <NUM> of the resilient ring <NUM>. In another embodiment, the engagement feature <NUM> can include a ridge extending around a circumference of the resilient ring <NUM>. The notch(es) or ridge can extend continuously or discontinuously around the resilient ring <NUM>. In yet a further embodiment, the engagement feature <NUM> can include a cutout <NUM>. In a particular instance, the cutout <NUM> can extend from the outer surface <NUM> into the resilient ring <NUM>.

The engagement feature <NUM> can define a first axial end <NUM> and a second axial end <NUM>. In certain instances, the first and second axial ends 220A and 220B can be parallel, or generally parallel with respect to one another. In other instances, the first and second axial ends 220A and 220B can be angularly offset from one another. For example, the first and second axial ends 220A and 220B can define negatively-sloped surfaces relative to the outer surface <NUM> of the resilient ring <NUM>, thus creating a cutout <NUM> with an increasing dimension as measured from the outer surface <NUM> into the body of the resilient ring <NUM>. The first and second axial ends 220A and 220B can be spaced apart by a distance corresponding generally with a distance required to secure one or more polymer rings (described in greater detail below) with the resilient ring <NUM>.

In certain instances, the engagement feature <NUM> can have a generally same shape as measured around the circumference of the resilient ring <NUM>. In other instances, the engagement feature <NUM> can have a generally same size as measured around the circumference of the resilient ring <NUM>. In yet other instances, the engagement feature <NUM> can have a generally same shape and a generally same size as measured around the circumference of the resilient ring <NUM>.

The seal <NUM> includes a first polymer ring <NUM> coupled with the resilient ring <NUM>. The first polymer ring <NUM> can be disposed adjacent to the first axial end <NUM> of the resilient ring <NUM>. In an embodiment, the first polymer ring <NUM> can contact the first axial end <NUM> of the resilient ring <NUM>. In a relaxed state (i.e., when the seal <NUM> is not yet installed in the ball valve <NUM>), the first polymer ring <NUM> can have a diameter, as measured between an innermost location and an outermost location of the first polymer ring <NUM>, that is greater than the diameter of the resilient ring <NUM>.

According to the invention, the first polymer ring <NUM> is coupled with the engagement feature <NUM> of the resilient ring <NUM>. In a more particular embodiment, the first polymer ring <NUM> can include a first complementary engagement feature <NUM> adapted to engage with the engagement feature <NUM> of the resilient ring <NUM>. For example, the first polymer ring <NUM> can be coupled with the resilient ring <NUM> at a location adjacent to the first axial end <NUM> of the engagement feature <NUM>. More particularly, the first polymer ring <NUM> can be engaged with the first axial end <NUM>.

In an embodiment, the first complementary engagement feature <NUM> can include a barb <NUM>. The barb <NUM> can have a surface <NUM> adapted to couple with the first axial end <NUM> of the engagement feature <NUM>. In an embodiment, the surface <NUM> of the barb <NUM> can have a profile similar or the same as the surface of the first axial end <NUM> of the engagement feature <NUM>. In a particular embodiment, the surface of the first axial end <NUM> of the engagement feature <NUM> lies along a best fit plane generally perpendicular to the central axis of the seal <NUM>. In a more particular embodiment, the surface of the first axial end <NUM> lies along a plane perpendicular to the central axis of the seal <NUM>. The surface <NUM> of the barb <NUM> can be adapted to lie parallel with the surface of the first axial end <NUM>.

To assemble the seal <NUM>, the first polymer ring <NUM> and resilient ring <NUM> can be axially moved, such as translated, relative to one another. For example, the first polymer ring <NUM> can be axially slid relative to the resilient ring <NUM> in a first direction <NUM> until the first complementary engagement feature <NUM> engages the engagement feature <NUM>.

Upon contacting the resilient ring <NUM>, the first complementary engagement feature <NUM> of the first polymer ring <NUM> can deform, such as flex. In an embodiment, deformation can occur in a radially outward direction. Chamfered edge <NUM> can assist in installation of the first polymer ring <NUM> relative to the resilient ring <NUM>. More specifically, the first complementary engagement feature <NUM> can have a profile adapted to be guided by the chamfered edge <NUM>. Even more specifically, the first complementary engagement feature <NUM> can have a chamfered edge <NUM> adapted to contact the chamfered edge <NUM> of the resilient ring <NUM> during installation. In a particular instance, the chamfered edges <NUM> and <NUM> can lie along same, or generally same, planes. The chamfered edges <NUM> and <NUM> can permit guiding of the first polymer ring <NUM> with respect to the resilient ring <NUM>.

The first polymer ring <NUM> can be slid in the first direction <NUM> until the first complementary engagement feature <NUM> (or barb <NUM>) arrives at the engagement feature <NUM>. Upon arriving at the engagement feature <NUM>, the first complementary engagement feature <NUM> can deform, such as flex, to engage with the engagement feature <NUM>. In an embodiment, deformation, or flexure, of the first complementary engagement feature <NUM> upon arriving at the engagement feature <NUM> can occur in a radially inward direction. In a particular instance, inward deformation of the first complementary engagement feature <NUM> can occur as a snap of the first complementary engagement feature <NUM>. In an embodiment, the snap can result in a tactile, audible, or otherwise perceptible indication to the operator performing the assembly. In such a manner, the first polymer ring <NUM> can be coupled with the resilient ring <NUM> and prevent from axially separating therefrom.

In an embodiment, the first polymer ring <NUM> can include an energized zone <NUM>. In a more particular embodiment, the energized zone <NUM> can be part of a same body <NUM> as the first complementary engagement feature <NUM>. In certain instances, the energized zone <NUM> and first complementary engagement feature <NUM> can be integral with one another, such as formed from a single monolithic body. In other instances, the energized zone <NUM> can be formed from a first component and the first complementary engagement feature <NUM> can be formed from a second component coupled with the first component.

In the illustrated embodiment, the energized zone <NUM> defines a diameter, as measured between an innermost location and an outermost location of the energized zone <NUM>, greater than a diameter of the first complementary engagement feature <NUM>. For example, by way of a non-limiting embodiment, the diameter of the energized zone <NUM> can be at least <NUM> times greater than the diameter of the first complementary engagement feature <NUM>. More particularly, the diameter of the energized zone <NUM> can be at least <NUM> times greater than the diameter of the first complementary engagement feature <NUM>, at least <NUM> times greater, at least <NUM> times greater, at least <NUM> times greater, at least <NUM> times greater, or at least <NUM> times greater. In another embodiment, the diameter of the energized zone <NUM> can be no greater than <NUM> times greater than the diameter of the first complementary engagement feature <NUM>, or no greater than <NUM> times greater than the diameter of the first complementary engagement feature <NUM>.

In an embodiment, the first complementary engagement feature <NUM> can extend from an outer portion of the energized zone <NUM>. In the illustrated embodiment, an outer surface <NUM> of the body <NUM> of the first polymer ring <NUM> can formed by a combination of the energized zone <NUM> and first complementary engagement feature <NUM>. In a particular embodiment, the surface <NUM> can be continuous. That is, the surface <NUM> can appear featureless, smooth, or otherwise non-indicative of a transition in the cross-sectional shape of the body <NUM> to an observer viewing the seal <NUM> after assembly.

In a particular embodiment, the energized zone <NUM> can have a cross-sectional shape forming a capital E. Members, such as middle member <NUM>, of the energized zone can extend toward the axial end <NUM> of the first polymer ring <NUM>. In an embodiment, the middle member <NUM> is longer than inner member <NUM> and outer member <NUM>.

The energized zone <NUM> can define one or more cavities 238A and 238B. In an embodiment, the cavities 238A and 238B can be disposed adjacent to a first axial end <NUM> of the first polymer ring <NUM>.

In certain embodiments, the first polymer ring <NUM> can include a transition zone <NUM> disposed between the energized zone <NUM> and the first complementary engagement feature <NUM>. In a particular embodiment, the transition zone <NUM> can have a tapering cross-sectional shape. In a more particular embodiment, the transition zone <NUM> can have a chamfered edge adapted to seat relative to the chamfered edge <NUM> of the resilient ring <NUM> when the first polymer ring <NUM> is engaged therewith.

At least one energizing element <NUM> can be disposed within or adjacent to the first polymer ring <NUM>. In an embodiment, the at least one energizing element <NUM> can include at least two energizing elements, at least three energizing elements, at least four energizing elements, or at least five energizing elements. In an embodiment, the at least one energizing element <NUM> can include no greater than fifty energizing elements, no greater than twenty-five energizing elements, no greater than ten energizing elements, or no greater than six energizing elements.

In a particular instance, the at least one energizing element <NUM> includes a first energizing element and a second energizing element. The first energizing element can be disposed at least partially radially inside of the second energizing element. In a particular embodiment, the first and second energizing elements can lie along a straight line extending perpendicular to the central axis of the first polymer ring <NUM>.

In an embodiment, the at least one energizing element <NUM> can include a spring. The spring can include, for example, a spring having a round cross-sectional shape such as a helical spring, a double coiled spring, a U-shaped spring, a C-shaped spring, a V-shaped spring, or any other shaped spring adapted to provide a radially outward biasing force. In certain instances, the first and second energizing elements can have a same, or generally same, shape, spring constant, size, or other similar characteristic as compared to one another. In other instances, the first and second energizing elements can have different shapes, different spring constants, different sizes, or one or more other different characteristics as compared to one another. In a particular embodiment, the first and second energizing elements have different energizing capacities (e.g., different spring constants). More particularly, the second energizing element, disposed radially outside of the first energizing element, can have a greater energizing capacity as compared to the energizing capacity of the first energizing element. In a particular instance, use of an outer energizing element with a greater energizing capacity can enhance sealing characteristic of the seal <NUM> as compared to a seal with an inner-energizing element with a greater energizing capacity.

As illustrated in <FIG>, in a non claimed embodiment, the seal <NUM> can include the resilient ring <NUM> and the first polymer ring <NUM> coupled together. In the non claimed embodiment, the resilient ring <NUM> can include half, or generally half, of the resilient ring <NUM> described with respect to <FIG>. In another embodiment, the resilient ring <NUM> can include a shape similar to that described with respect to <FIG>.

Referring again to <FIG>, according to the invention, the seal <NUM> further includes a second polymer ring <NUM>. The second polymer ring <NUM> can include any number of similar or different features as compared to the first polymer ring <NUM>. In an embodiment, the first and second polymer rings <NUM> and <NUM> are symmetrical. In a more particular embodiment, the first and second polymer rings <NUM> and <NUM> reflectively symmetrical.

The second polymer ring <NUM> can be disposed adjacent to the resilient ring <NUM>. More particularly, the second polymer ring <NUM> can be disposed adjacent to the second axial end <NUM> of the resilient ring <NUM>.

In an embodiment, the second polymer ring <NUM> can include a second complementary engagement feature <NUM> coupled with an energized zone <NUM>. The second complementary engagement feature <NUM> can be adapted to couple with the resilient ring <NUM>. More particularly, the second complementary engagement feature <NUM> can be adapted to couple with the engagement feature <NUM> of the resilient ring <NUM>. Even more particularly, in an embodiment, the second complementary engagement feature <NUM> can include a barb <NUM> adapted to couple with the second axial end <NUM> of the engagement feature <NUM>.

To assemble the seal <NUM>, the second polymer ring <NUM> and resilient ring <NUM> can be axially moved, such as translated, relative to one another. For example, the second polymer ring <NUM> can be axially slid relative to the resilient ring <NUM> in a second direction (opposite or generally opposite the first direction <NUM>) until the second complementary engagement feature <NUM> engages the engagement feature <NUM>.

Upon contacting the resilient ring <NUM>, the second complementary engagement feature <NUM> of the second polymer ring <NUM> can deform, such as flex. In an embodiment, deformation can occur in a radially outward direction. Chamfered edge <NUM> can assist in installation of the second polymer ring <NUM> relative to the resilient ring <NUM>. More specifically, the second complementary engagement feature <NUM> can have a profile adapted to be guided by the chamfered edge <NUM>. Even more specifically, the second complementary engagement feature <NUM> can have a chamfered edge adapted to contact the chamfered edge <NUM> of the resilient ring <NUM> during installation. In a particular instance, the chamfered edge of the second complementary feature <NUM> can lie along same, or generally same, plane as the chamfered edge <NUM> of the resilient ring <NUM>. The chamfered edges can permit guiding of the second polymer ring <NUM> with respect to the resilient ring <NUM>.

The second polymer ring <NUM> can be slid in the second direction until the second complementary engagement feature <NUM> arrives at the engagement feature <NUM>. Upon arriving at the engagement feature <NUM>, the second complementary engagement feature <NUM> can deform, such as flex, to engage with the engagement feature <NUM>. In an embodiment, deformation, or flexure, of the second complementary engagement feature <NUM> upon arriving at the engagement feature <NUM> can occur in a radially inward direction. In a particular instance, inward deformation of the second complementary engagement feature <NUM> can occur as a snap of the second complementary engagement feature <NUM>. In an embodiment, the snap can result in a tactile, audible, or otherwise perceptible indication to the operator performing the assembly. In such a manner, the second polymer ring <NUM> can be coupled with the resilient ring <NUM> and prevent the second polymer ring <NUM> and resilient ring <NUM> from axially separating.

According to the invention, the first and second polymer rings <NUM> and <NUM> contact one another when coupled with the resilient ring <NUM>. In an embodiment, the first complementary engagement feature <NUM> can contact the second complementary engagement feature <NUM>. In a more particular embodiment, the first complementary engagement feature <NUM> can contact the second complementary engagement feature <NUM> at a location corresponding in an axial direction with the engagement feature <NUM>. That is, for example, contact between the first and second complementary engagement features <NUM> and <NUM> can occur along a plane perpendicular to the central axis of the seal <NUM> and intersecting the engagement feature <NUM> of the resilient ring <NUM>. In a particular embodiment, the first and second complementary engagement features <NUM> and <NUM> can contact one another a location equally, or generally equally, spaced apart from the axial ends <NUM> and <NUM> of the complementary engagement feature <NUM>.

In an embodiment, the first and second complementary engagement features <NUM> and <NUM> can have at least one of a generally same cross-sectional shape, a generally same cross-sectional area, a generally same cross-sectional dimension, or any combination thereof. In a more particular embodiment, the first and second complementary engagement features <NUM> and <NUM> can have at least one of a same cross-sectional shape, a same cross-sectional area, a same cross-sectional dimension, or any combination thereof.

In certain instances, at least one of the first and second polymer rings <NUM> and <NUM> can include a thermoplastic material. In an embodiment, at least one of the first and second polymer rings <NUM> and <NUM> can include a nylon, a polyether ether ketone (PEEK), polyether sulfone (PES), polytetrafluoroethylene (PTFE), polyimide, or an organic or inorganic composite. Further exemplary polymers include fluorinated ethylene-propylene (FEP), polyvinylidenfluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene chlorotrifluoroethylene (ECTFE), perfluoroalkoxy alkane (PFA), polyacetal, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyimide (PI), polyetherimide, polyethylene (PE), polysulfone, polyamide (PA), polyphenylene oxide, polyphenylene sulfide (PPS), polyurethane, polyester, liquid crystal polymers (LCP), or any combination thereof.

In an embodiment, at least one of the first and second polymer rings <NUM> and <NUM>, can include a filler. Exemplary fillers include glass fibers, carbon fibers, silicon, PEEK, aromatic polyester, carbon particles, bronze, fluoropolymers, thermoplastic fillers, aluminum oxide, polyamidimide (PAI), PPS, polyphenylene sulfone (PPSO2), LCP, aromatic polyesters, molybdenum disulfide, tungsten disulfide, graphite, grapheme, expanded graphite, boron nitrade, talc, calcium fluoride, or any combination thereof. Additionally, the filler can include alumina, silica, titanium dioxide, calcium fluoride, boron nitride, mica, Wollastonite, silicon carbide, silicon nitride, zirconia, carbon black, pigments, or any combination thereof.

In an embodiment, the first and second polymer rings <NUM> and <NUM> can be parts of a single polymer element. That is, for example, the first and second polymer rings <NUM> and <NUM> can be integral with one another. More specifically, the first and second polymer rings <NUM> and <NUM> can be formed from, or include, a single body.

Claim 1:
A seal (<NUM>) for a ball valve (<NUM>) comprising:
a resilient ring (<NUM>) defining an engagement feature (<NUM>);
a first polymer ring (<NUM>) disposed adjacent to a first axial end (<NUM>) of the resilient ring (<NUM>) and coupled with the engagement feature (<NUM>); and
a second polymer ring (<NUM>) disposed adjacent to a second axial end (<NUM>) of the resilient ring (<NUM>) and coupled with the engagement feature (<NUM>),
wherein the first polymer ring (<NUM>) contacts the second polymer ring (<NUM>) at an axial location corresponding with the engagement feature (<NUM>).