Patent Description:
Seals are typically used to prevent leakage from occurring within an annulus between two or more components. For example, a seal may be used in hardware between inner and outer components, such as a shaft and a bore. The seal may be positioned between the shaft and the bore to maintain different fluidic pressures or to separate different fluidic components on opposing sides of the seal.

In many applications, for instance in oil and gas drilling and refining operations, it is necessary for seals to withstand wide temperature ranges while maintaining effective sealing characteristics. Industries utilizing seals continue to demand improved seal performance over a wide range of environmental conditions.

Related patent application <CIT> shows an annular seal having several features in common with the presently claimed invention.

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 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 sealing arts.

Seals are generally used in hardware to isolate volumes and pressures from one another. In particular, seals can be used in hardware adapted for use in harsh environmental conditions, such as at low temperatures, and required to meet certain leakage performance metrics.

In one or more embodiments, a seal can include an annular body adapted to fit around an inner component and within an outer component. In particular, the seal can fit within an annulus defined between the inner and outer components. In certain instances, the seal can be adapted to have a fugitive emission measured leakage rate, as measured according to ISO <NUM>-<NUM>, less than <NUM>*s-<NUM>*m-<NUM>. In a more particular embodiment, the seal can be certified as Class AH compliant, as measured according to ISO <NUM>-<NUM>.

In one or more embodiments, the seal can include a plurality of rings stacked together in axial alignment. The plurality of rings can include, for example, a first energized jacket, a second energized jacket, and a plurality of seal rings. The first and second energized jackets can be stacked adjacent to one another. In an embodiment, the second energized jacket can be disposed between the first energized jacket and the plurality of seal rings. A spacer can be positioned between the first and second energized jackets and extend at least partially into the second energized jacket.

In an embodiment, the first and second energized jackets can include different types of energizing elements. For example, the first energized jacket can include a coiled spring having a generally "O" shaped cross-sectional profile and the second energized jacket can include a cantilevered spring having a generally U-shaped cross-sectional profile.

In certain instances, the first and second energized jackets can operate differently. For example, the first energized jacket can operate under axial pressure generated within the annulus on a first axial end of the seal. The pressure can cause the first energized jacket to radially bias into the hardware, thus generating a primary effective sealing condition. Meanwhile, the second energized jacket can operate under mechanical loading caused by the first energized jacket (or the spacer disposed between the first and second energized jackets). That is, the first energized jacket (or the spacer disposed between the first and second energized jackets) can mechanically load the second energized jacket to generate a secondary effective sealing condition.

<FIG> include cross-sectional views of a seal <NUM> in accordance with an embodiment. The seal <NUM> includes a first energized jacket <NUM> and a second energized jacket <NUM>. In an embodiment, the first energized jacket <NUM> can define a first axial end <NUM> of the seal <NUM>. The first axial end <NUM> of the seal <NUM> can be adapted for use on a relatively high-pressure region of a hardware (not illustrated). The resulting load from the high-pressure region can bias the first energized jacket <NUM> toward a relatively low-pressure side of the hardware.

The first energized jacket <NUM> can include a body <NUM> defining a volume <NUM> at least partially containing a first energizing element <NUM>.

In an embodiment, the body <NUM> can include a polymeric material. Exemplary polymers include tetrafluoroethylene (TFE) such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), perfluoroalkoxy (PFA), polychlorotrifluoroethylene (PCTFE), polyethylenetetrafluoroethylene (ETFE), vinylidene fluoride (THV), polyethylenechlorotrifluoroethylene (ECTFE), polyether ether ketone (PEEK), or any combination thereof. The scope of the disclosure is not intended to be limited to those exemplary polymers listed above. In a particular embodiment, the body <NUM> includes PTFE, such as, for example, FLUOROLOY® A02 (available from Saint-Gobain Performance Plastics). FLUOROLOY® A02 exhibits a tensile strength, as measured according to ASTM D4894, of <NUM> MPa, an elongation, as measured according to ASTM D4894, of <NUM>%, a compressive modulus, as measured according to ASTM D695, of <NUM> MPa, a deformation under load, as measured according to ASTM D621 and as tested at <NUM>,<NUM> PSI for <NUM> hours, of <NUM>%, a Shore D hardness, as measured according to ASTM D2240, of between <NUM> and <NUM>, and a coefficient of linear thermal expansion, as measured according to ASTM E831 between <NUM> and <NUM>, of <NUM>/m/°C.

One or more fillers can be included in the body <NUM> of the first energized jacket <NUM>. For instance, 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 nitride, 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 energizing element <NUM> can be fully contained within the volume <NUM> of the body <NUM> such that the first axial end <NUM> of the seal <NUM> is defined by one or more portions of the body <NUM>. In a more particular embodiment, at least a portion of the first energizing element <NUM> can be visible from the first axial end <NUM> of the seal <NUM>. In certain instances, at least <NUM>% of the first energizing element <NUM> can be disposed in the volume <NUM>, at least <NUM>% of the first energizing element <NUM> can be disposed in the volume <NUM>, at least <NUM>% of the first energizing element <NUM> can be disposed in the volume <NUM>, or at least <NUM>% of the first energizing element <NUM> can be disposed in the volume. In a more particular embodiment, the entire first energizing element <NUM> can be disposed in the volume <NUM>.

The first energizing element <NUM> can include a deformable energizer, such as a spring, adapted to bias the body <NUM> of the first energized jacket <NUM> into the hardware. In an embodiment, first energizing element <NUM> can include a double coiled spring, a single coiled spring, an advanced pitch spring, a cantilevered spring, or a plurality of cantilevered springs. In a particular embodiment, the first energizing element <NUM> can have a generally "O" shaped cross-sectional profile. In an embodiment, the first energizing element <NUM> can be formed from a metal, alloy, or other resilient material. Exemplary alloys may include cobalt and nickel. In certain instances, the first energizing element <NUM> can be heat treated to increase mechanical properties.

The second energizing jacket <NUM> can include a body <NUM> defining a volume <NUM> at least partially containing a second energizing element <NUM>. In an embodiment, the body <NUM> can include a polymeric material. Exemplary polymers include tetrafluoroethylene (TFE) such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), perfluoroalkoxy (PFA), polychlorotrifluoroethylene (PCTFE), polyethylenetetrafluoroethylene (ETFE), vinylidene fluoride (THV), polyethylenechlorotrifluoroethylene (ECTFE), polyether ether ketone (PEEK),or any combination thereof. The scope of the disclosure is not intended to be limited to those exemplary polymers listed above. In a particular embodiment, the body <NUM> includes PTFE, such as, for example, FLUOROLOY® A02 (available from Saint-Gobain Performance Plastics).

One or more fillers can be included in the body <NUM> of the second energized jacket <NUM>. For instance, 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 nitride, 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 second energizing element <NUM> can be fully contained within the volume <NUM> of the body <NUM>. In certain instances, at least <NUM>% of the second energizing element <NUM> can be disposed in the volume <NUM>, at least <NUM>% of the second energizing element 118can be disposed in the volume <NUM>, at least <NUM>% of the second energizing element 118can be disposed in the volume <NUM>, or at least <NUM>% of the second energizing element 118can be disposed in the volume <NUM>. In a more particular embodiment, the entire first energizing element <NUM> can be disposed entirely in the volume <NUM>.

In a particular embodiment, the body <NUM> can include one or more retention features <NUM> adapted to prevent extrusion of the second energizing element <NUM> from the volume <NUM>. The retention feature <NUM> can include, for instance, a notch or structure extending into the volume <NUM> to prevent axial translation of the second energizing element <NUM> from the volume <NUM>. The exemplary embodiment illustrated in <FIG> includes the retention feature <NUM> on an outer surface <NUM> of the volume <NUM>. However, in other embodiments, the retention feature <NUM> can be disposed on an inner surface <NUM> of the volume <NUM> or the body <NUM> can include a plurality of retention features (e.g., one retention feature on the inner surface <NUM> and one retention feature on the outer surface <NUM>).

The second energizing element <NUM> can include a deformable energizing element, such as a spring, adapted to bias the body <NUM> of the second energized jacket <NUM> into the hardware. The second energizing element <NUM> can include a double coiled spring, a single coiled spring, an advanced pitch spring, a cantilevered spring, or a plurality of cantilevered springs. In an embodiment, the first and second energizing elements <NUM> and <NUM> can include different types of energizing elements, as compared to one another. For instance, the first energizing element <NUM> can include a double coiled spring and the second energizing element <NUM> can include a cantilever spring. The cantilever spring can have a generally "U" shaped cross-sectional profile. In another embodiment, the first and second energizing elements <NUM> and <NUM> can include the same type of energizing elements, as compared to one another. The second energizing element <NUM> can be formed from a metal, alloy, or other resilient material. Exemplary alloys may include cobalt and nickel.

The body <NUM> of the second energized jacket <NUM> can define a radially inner surface <NUM> and a radially outer surface <NUM>. At least one of the radially inner and outer surfaces <NUM> and <NUM> can include one or more sealing features <NUM> adapted to create enhanced fluidic sealing characteristics. In an embodiment, the one or more sealing features <NUM> can include at least one sealing feature, at least two sealing features, at least three sealing features, at least four sealing features, or at least five sealing features. The sealing features <NUM> can include ridges, bumps, dimples, scrapers, edges, castellation, another radially projecting surface feature, or any combination thereof. In an embodiment, the sealing features <NUM> can extend around at least a portion of a circumference of the body <NUM>. In a particular embodiment, at least one of the sealing features <NUM> can extend continuously around the entire circumference of the body. That is, the at least one sealing feature <NUM> can have an uninterrupted and similar shaped profile around the entire circumference of the body <NUM>. For instance, in the illustrated embodiment (<FIG>), the sealing features <NUM> extend around the entire circumference of the body <NUM> of the second energized jacket <NUM>.

In the illustrated embodiment, the sealing feature <NUM> includes a first sealing feature 130A and a second sealing feature 130B disposed on the radially outer surface <NUM> of the body <NUM>. In the uninstalled state illustrated in <FIG> (i.e., prior to installation of the seal <NUM> within hardware), the first and second sealing features 130A and 130B can have different heights as compared to one another and as measured from the radially outer surface <NUM> of the body. For instance, in the illustrated embodiment, the first sealing feature 130A is taller than the second sealing feature 130B. By way of example, the first sealing feature 130A can be at least <NUM> times taller than the second sealing feature 130B, at least <NUM> times taller than the second sealing feature 130B, at least <NUM> times taller than the second sealing feature 130B, or at least <NUM> times taller than the second sealing feature 130B.

During installation, the body <NUM> of the second energized jacket <NUM> may deform to fit within the annulus of the hardware. More particularly, axial extensions 132A and 132B of the body <NUM> may deform toward one another from a hub <NUM> of the body <NUM> in a generally cantilevered manner. Such deformation may alter the relative, effective difference in height of the first and second sealing features 130A and 130B. That is, the perceived heights (i.e., the distance from central axis A) of the first and second sealing features 130A and 130B may be more similar in the installed state as compared to the uninstalled state. In a particular embodiment, the perceived height of the first and second sealing features 130A and 130B, as measured in the installed state, may be approximately the same as measured from the central axis A. In an embodiment, sealing load applied between the first sealing feature 130A and hardware can be approximately equal to sealing load applied between the second sealing feature 130B and the hardware. In another embodiment, sealing load between the hardware and the first sealing feature 130A may be different from sealing load between the hardware and the second sealing feature 130B. For instance, sealing load generated between the first sealing feature 130A and the hardware may be greater than sealing load generated between the second sealing feature 130B and the hardware. The plurality of sealing features <NUM> can provide redundant sealing characteristics. A pocket formed between the sealing features 130A and 130B may trap leaked fluids and prevent egress thereof from the relatively low-pressure side of the hardware. In an embodiment, the radially inner and outer surfaces of the body <NUM> can define a different number of annular ridges <NUM> as compared to one another. For by way of non-limiting example, the radially inner surface can have one or three annular ridges <NUM> and the radially outer surface can have two or four annular ridges <NUM>. It is noted that the body <NUM> can include a different number of annular ridges <NUM> arranged on the radially inner and outer surfaces.

As illustrated, the first and second energized jackets <NUM> and <NUM> can be disposed adjacent, or nearly adjacent to one another. The first energized seal <NUM> can form a primary sealing interface adapted to handle relatively high-pressure within the hardware. Pressure from the contained liquid can cause the body <NUM> of the first energized jacket <NUM> to bias radially into the hardware. The second energized jacket <NUM> can be mechanically biased by the first energizing jacket <NUM> or a spacer <NUM> disposed between the first and second energized jackets <NUM> and <NUM>.

In an embodiment, the spacer <NUM> can be disposed between the first and second energized jackets <NUM> and <NUM>. The spacer <NUM> can transmit axial loading from the first energized jacket <NUM> to the second energized jacket <NUM>. In an embodiment, the spacer <NUM> can include a base <NUM> and a support <NUM>. The support <NUM> can extend from the base <NUM> in a direction toward the second energized jacket <NUM>. In a more particular embodiment, the support <NUM> can define a height, HS, as viewed in cross section and measured parallel with a central axis A of the seal <NUM>, generally perpendicular to a thickness, TB, of the base <NUM>.

In an embodiment, HS can be no less than <NUM> TB. In a more particular embodiment, HS can be no less than <NUM> TB, no less than <NUM> TB, no less than <NUM> TB, or no less than <NUM> TB. In another embodiment, HS can be no greater than <NUM> TB, no greater than <NUM> TB, or no greater than <NUM> TB. In a particular embodiment, and as described in greater detail below, the support height, HS, can be sized to fit within the volume <NUM> of the second energized jacket <NUM>.

In an embodiment, the thickness, TB, of the base <NUM> may lie along a plane oriented perpendicular to the central axis A of the seal <NUM>. The base <NUM> thickness, TB, as measured between radially inner and outer locations, can be less than a thickness of the annulus adapted to receive the seal <NUM>. In such a manner, the spacer <NUM> can be adapted to be spaced apart from the hardware in the installed state.

In an embodiment, the spacer <NUM> may include a single, monolithic body. The spacer <NUM> can be formed from a resilient material, such as a resilient polymer. In an embodiment, the spacer <NUM> can include a material having a higher strength as compared to the material of the first and second energized jackets <NUM> and <NUM>. By way of non-limiting example, the spacer <NUM> can include an aramid, such as an aromatic polyamide, an aromatic polyester, an aromatic polyether, or an aromatic polyurethane, as these materials exhibit a low coefficient of linear thermal expansion and a low elongation at break. Other exemplary polymers include: polyimides (such as, for example, the KAPTON brand polyimide available from E. I duPont deNemours and Co. , Wilmington, Delaware), polyparaphenylene (PPP, available from Maxdem, Inc. , San Dimas, California), poly (ethylene naphthalene <NUM>,<NUM>-dicarboxylate, PEN), poly(ethylene naphthalate-co-<NUM>,<NUM>- bibenzoate, PENBB), polyethylene terephthalate (PET), polycarbonate (PC), cycloolefin copolymers (COC, such as, for example, TOPAS® available from Hoechst Technical Polymers), polyphenylene sulfide (PPS), PES (polyether sulfone), polyaryletherketone (PAEK), polysulfones, polyacrylates (e.g., crosslinked polymethyl methacrylate,PMMA) and the like and mixtures thereof. In a particular embodiment, the spacer <NUM> can include Meldin. It will be recognized that this list is not exhaustive and that other materials can also be used in the composition of the spacer <NUM>.

In a non-illustrated embodiment, the spacer <NUM> can be integral with the first energized jacket <NUM>. That is, the spacer <NUM> can be integral, or monolithic, with the body <NUM> of the first energized jacket <NUM>. In certain instances, the spacer <NUM> may be defined as the portion of the body <NUM> that acts primarily to space apart the first and second energized jackets <NUM> and <NUM>.

Referring to <FIG>, the spacer <NUM> can define a first axial end surface <NUM> adapted to contact the body <NUM> of the first energized jacket <NUM>. In a more particular embodiment, the first axial end surface <NUM> of the spacer <NUM> can be adapted to contact a surface of a hub <NUM> of the first energized jacket <NUM>. In the illustrated embodiment, the first axial end surface <NUM> of the spacer <NUM> contacts the hub <NUM> of the first energized jacket <NUM> along a planar contact interface <NUM>. In an embodiment, the interface <NUM> can lie along a plane generally perpendicular with the central axis A of the seal <NUM>. As illustrated, the interface <NUM> can extend across an entire thickness of the spacer <NUM>. Use of a planar interface <NUM> between the first energized jacket <NUM> and the spacer <NUM> may enhance sealing characteristics of the seal <NUM> as compared to non-planar interfaces, such as arched interfaces, multi-planar interfaces, or both. In certain embodiments, the interface <NUM> can be approximately uniform in shape, size, or both, as measured around the circumference of the seal <NUM>. In a non-illustrated embodiment, the interface <NUM> between the first energized jacket <NUM> and the spacer <NUM> can be non-planar.

<FIG> includes an enlarged view of the spacer <NUM> and second energized jacket <NUM> of a seal <NUM> in accordance with an embodiment. As illustrated, the support <NUM> of the spacer <NUM> can define a tapered profile extending into the volume <NUM> of the second energized jacket <NUM>. In an embodiment, the support <NUM> can contact the second energizing element <NUM> in the installed state. In a more particular embodiment, a tip <NUM> of the support <NUM> can contact the second energizing element <NUM> in the installed and uninstalled states. In a more particular embodiment, side surfaces <NUM> of the support <NUM> can be spaced apart from the second energizing element <NUM> at least when the seal <NUM> is in the uninstalled state (i.e., prior to deflection caused by installation force from the hardware).

In a particular embodiment, the support <NUM> can define a first thickness, TS1, as measured at a first axial location <NUM> along the support <NUM>, and a second thickness, TS2, as measured at a second axial location <NUM> along the support <NUM>, where TS1 is not equal to TS2. For instance, TS1 can be less than TS2. By way of example, TS1 can be no greater than <NUM> TS2, no greater than <NUM> TS2, no greater than <NUM> TS2, no greater than <NUM> TS2, no greater than <NUM> TS2, no greater than <NUM> TS2, no greater than <NUM> TS2, or no greater than <NUM> TS2. In another embodiment, TS1 can be no less than <NUM> TS2, no less than <NUM> TS2, or no less than <NUM> TS2. In an embodiment, the first axial location <NUM> can be disposed closer to the first axial end <NUM> of the seal <NUM> than the second axial location <NUM>.

In an embodiment, the support <NUM> can have a generally linear taper. That is, at least a portion of at least one side surface <NUM> of the support <NUM>, as viewed in cross section, can lie along a straight line L. In another embodiment, the support <NUM> can define an arcuate cross-sectional profile, a multi-faced polygonal cross-sectional profile, or both. In certain instances, the tip <NUM> of the support <NUM> can define a radius of curvature less than a radius of curvature of the second energizing element <NUM>. In an embodiment, the support <NUM> can extend from the base <NUM> at a curved or fileted interface to reduce cracking and interfacing issues therebetween.

In an embodiment, axial extensions 132A and 132B of the body <NUM> may deform toward one another as the seal <NUM> is installed within hardware. For instance, the first and second axial extensions 132A and 132B can define a first angle, as measured with respect to the central axis A of the seal <NUM> in the uninstalled state, and a second angle, as measured in the installed state, that are different from one another. In an embodiment, the first angle can be less than the second angle. In an embodiment, the second angle may be closer to a side angle, α, of the side surface <NUM> of the support <NUM> than the first angle. In an embodiment, the side angle, α, of the side surface <NUM> can be at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, or at least <NUM>°. Deflection of the axial extensions 132A and 132B exhibited during installation can be at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, or at least <NUM>°. That is, deflection can cause the axial extensions 132A and 132B to move toward the support <NUM>. In a particular embodiment, deflection of the axial extensions 132A and 132B is no greater than the side angle, α, of the side surface <NUM> of the support <NUM>. At maximum deflection, which may not be required for effective sealing characteristic, at least one of the first and second axial extensions 132A and 132B (or at least a portion of the second energizing element <NUM> associated therewith) may contact the support <NUM>. In this regard, the support <NUM> may define a maximum deflection capability of axial extensions 132A and 132B.

In a particular embodiment, the second energizing element <NUM>, one or both of the axial extensions 132A and 132B, or a combination thereof, may contact the side surface <NUM> of the support <NUM> when the seal <NUM> is fully installed within the hardware. That is, for example, inner surfaces <NUM> or <NUM> of the volume <NUM> may contact the side surface <NUM> of the support <NUM>. The second energizing element <NUM> can resist the deformation of the axial extensions 132A and 132B, generating a loading force of the second energized jacket <NUM> with respect to the hardware.

It is noted that the second energized jacket <NUM> illustrated in <FIG> includes rounded sealing features <NUM> whereas the second energized jacket <NUM> in <FIG> includes non-rounded sealing features <NUM>. The seal <NUM> can utilize a second energized jacket <NUM> including either rounded sealing features <NUM>, non-rounded sealing features <NUM>, or both. The uninstalled height of the sealing features <NUM> illustrated in <FIG> may be measured by a relative height from the central axis A of the seal <NUM> instead of the height from the radially outer surface <NUM> (<FIG>). In this regard, the sealing feature 130A in <FIG> is taller than sealing feature 130B.

As illustrated in <FIG>, the seal <NUM> can further include a plurality of seal rings <NUM>. In an embodiment, the seal rings <NUM> can define a chevron style packing. The seal rings <NUM> can be disposed on a relatively low-pressure side of the seal <NUM>. In an embodiment, the plurality of seal rings <NUM> can define a second axial end <NUM> of the seal <NUM>. The plurality of seal rings <NUM> can include, for example, a first axial end seal ring <NUM> and a second axial end seal ring <NUM> disposed on axial ends of the plurality of seal rings <NUM>. Second axial end seal ring <NUM> can define the second axial end <NUM> of the seal <NUM>. In an embodiment, an axial end of the second axial seal ring <NUM> can be planar. That is, for instance, the axial end of the second axial seal ring <NUM> can be oriented normal to the central axis A of the seal <NUM>. In certain instances, the axial end of the second axial seal ring <NUM> can be adapted to engage with a stop feature in the annulus of the hardware. The stop feature can prevent extrusion of the seal <NUM> from the hardware through the low pressure side. In an embodiment, the stop feature can be a projection extending into the annulus of the hardware. In another embodiment, the stop feature can include an end surface of the annulus.

One or more intermediary seal rings <NUM> can be disposed between the first and second axial end seal rings <NUM> and <NUM>. In certain instances, the one or more intermediary seal rings <NUM> can include at least one seal ring, at least two seal rings, at least three seal rings, at least four seal rings, or at least five seal rings. In an embodiment, the intermediary seal rings <NUM> can include first seal ring(s) <NUM> and second seal ring(s) <NUM>. In a particular embodiment, the first and second seal rings <NUM> and <NUM> can be alternated. The first and second seal rings <NUM> and <NUM> can have same or different properties (e.g., size, material composition, shape) as compared to one another. For instance, in an embodiment, the first seal rings <NUM> can include a first material and the second seal rings <NUM> can include a second material different from the first material. By way of non-limiting example, the first seal rings <NUM> can have a lower coefficient of friction and be adapted to flow more readily upon application of loading forces while the second seal rings <NUM> can be more ridged and adapted to contain the flowing first seal rings <NUM> during loading.

In an embodiment, the first and second axial end seal rings <NUM> and <NUM> can include a first material composition and the intermediary seal rings <NUM> can include a second material composition different than the first material composition. By way of example, the first material composition can include a more resilient material and the second material composition can have a lower coefficient of friction.

In an embodiment, the first axial end seal ring <NUM> can define a first axial end surface <NUM> adapted to contact the body <NUM> of the second energized jacket <NUM>. In a more particular embodiment, the first axial end surface <NUM> of the first axial end seal ring <NUM> can be adapted to contact a surface of a hub <NUM> of the second energized jacket <NUM>. In the illustrated embodiment, the first axial end surface <NUM> of the first axial end seal ring <NUM> contacts the hub <NUM> of the second energized jacket <NUM> along a planar contact interface <NUM>. In an embodiment, the interface <NUM> can lie along a plane generally perpendicular with a central axis A of the seal <NUM>. As illustrated, the interface <NUM> can extend across an entire thickness of the first axial end seal ring <NUM>, hub <NUM>, or both. Use of a planar interface <NUM> between the second energized jacket <NUM> and the first axial end seal ring <NUM> may enhance sealing characteristics of the seal <NUM> as compared to non-planar interfaces, such as arched interfaces, multi-planar interfaces, or both. In certain embodiments, the interface <NUM> can be approximately uniform in shape, size, or both, as measured around the circumference of the seal <NUM>. In a non-illustrated embodiment, the interface <NUM> can be non-planar.

In a non-illustrated embodiment, the first axial end seal ring <NUM> can be integral with the second energized jacket <NUM>. That is, the first axial end seal ring <NUM> can be integral, or monolithic, with the body <NUM> of the second energized jacket <NUM>. In certain instances, the first axial end seal ring <NUM> may be defined as the portion of the body <NUM> that acts primarily to interface the second jacket <NUM> with the plurality of seal rings <NUM>.

In certain instances, elements of the seal <NUM> may freely float with respect to one another. That is, at least two of the first energized jacket <NUM>, the second energized jacket <NUM>, the spacer <NUM>, and the plurality of seal rings <NUM> may be adapted to axially translate with respect to one another. In an embodiment, at least two of the first energized jacket <NUM>, the second energized jacket <NUM>, the spacer <NUM>, and the plurality of seal rings <NUM> may be installed independently (i.e., at different times - e.g., in succession) with respect to one another. The elements of the seal <NUM> can be stacked prior to insertion into the hardware to ensure proper orientation during installation.

<FIG> includes a cross-sectional view of a seal <NUM> in accordance with another embodiment, not showing the plurality of seal rings which are also part of this embodiment.

The first energized jacket <NUM> can be similar to the first energized jacket <NUM> previously described. A spacer <NUM> can be disposed between the first energized jacket <NUM> and a second energized jacket <NUM>.

The second energized jacket <NUM> can include a first sealing element <NUM> defining a concavity <NUM> recessed from an axial surface <NUM> thereof and a second sealing element <NUM> disposed at least partially within the concavity <NUM>. The second sealing element <NUM> can define a concavity <NUM> recessed from an axial surface <NUM> thereof. An energizing element <NUM> can be disposed at least partially within the concavity <NUM> of the second sealing element <NUM>.

In an embodiment, at least <NUM>% of the second sealing element <NUM> can be disposed within a volume defined by the concavity <NUM>, at least <NUM>% of the second sealing element <NUM> can be disposed within a volume defined by the concavity <NUM>, at least <NUM>% of the second sealing element <NUM> can be disposed within a volume defined by the concavity <NUM>, or at least <NUM>% of the second sealing element <NUM> can be disposed within a volume defined by the concavity <NUM>.

In an embodiment, the second sealing element <NUM> can contact the first sealing element <NUM> along a surface of the first sealing element <NUM> defining the concavity <NUM>. In a more particular embodiment, the first and second sealing elements <NUM> and <NUM> can be close-fit with respect to one another. That is, for example, the contours of the mating surfaces of the first and second sealing elements <NUM> and <NUM> can be adapted to have similar shapes for close arrangement between the two parts.

In an embodiment, the concavity <NUM> of the second sealing element <NUM> can have a profile adapted to retain the energizing element <NUM> therein. For instance, the thickness of the concavity <NUM> can be less than the thickness of the energizing element <NUM> at, or near, the opening of the concavity <NUM>.

In an embodiment, the first and second sealing elements <NUM> and <NUM> can include complementary retention features <NUM> adapted to secure the first and second sealing elements <NUM> and <NUM> together. By way of non-limiting example, the complementary retention feature <NUM> can include a notch and groove adapted to snap fit together.

In an embodiment, the second sealing element <NUM> can include a multiple-piece construction. For instance, the second sealing element <NUM> can include a radially inner portion <NUM> and a radially outer portion <NUM> spaced apart from one another by the concavity <NUM>. The complementary retention feature <NUM> can prevent relative axial translation between the radially inner and outer portions <NUM> and <NUM>.

In an embodiment, the second sealing element <NUM> can define an axial end <NUM> having a profile adapted to mate with a surface <NUM> of the spacer <NUM>. Loading applied on the second sealing element <NUM> by the spacer <NUM> can bias the second sealing element <NUM> radially outward toward the hardware. In such a manner, the second sealing element <NUM> can either contact the hardware, bias the first sealing element <NUM> into the hardware, or both to form an effective sealing condition.

In an embodiment, the spacer <NUM> is axially spaced apart from the concavity <NUM> of the first sealing element <NUM>. In another embodiment, the spacer <NUM> is spaced apart from at least a majority of the concavity <NUM> of the second sealing element <NUM>. Use of a spacer <NUM> without support (e.g., support <NUM> previously described) may be suitable for applications where the energizing element <NUM> is a spring having a non-cantilevered profile. Use of a spacer support for non-cantilevered springs may result in damage to the non-cantilevered spring during high loading conditions.

A seal is installed in an assembly between a bore having a <NUM> diameter and a shaft having a <NUM> diameter. The seal has a central opening with a diameter of <NUM> and an outer diameter of <NUM>. The seal comprises the design illustrated in <FIG>. Specifically, the seal includes a first energized jacket <NUM>, a second energized jacket <NUM>, a plurality of seal rings <NUM> including two intermediary seal rings <NUM>, and a spacer <NUM> between the first and second energized jackets <NUM> and <NUM>.

To test fugitive emissions leakage, the assembly is cycled between room temperature (approximately <NUM>) and a cold temperature (-<NUM>) at the rate illustrated in Chart <NUM> below. Helium is used as the test fluid with measurements made using a vacuum method defined in Annex A of ISO <NUM>-<NUM>. Leakage is measured per mm of stem diameter.

<FIG> includes a graph <NUM> depicting assembly leakage <NUM> as a function of temperature cycle. The temperature profile <NUM> is adjusted according to Chart <NUM> above. Class AH sealing performance is indicated by line <NUM>. Class BH sealing performance is indicated by line <NUM>. As illustrated, the assembly leakage <NUM> performed within both Class AH and Class BH criteria. More specifically, the sample seal exhibited a fugitive emission measured leakage rate (mass flow) less than <NUM> × <NUM>-<NUM> mg*s-<NUM>*m-<NUM> per stem perimeter, as measured according to ISO <NUM>-<NUM>. The sample seal may exhibit the above leakage rate or better over endurance classes of CO1 (<NUM> cycles), CO2 (<NUM> cycles), and CO3 (<NUM> cycles).

To test fugitive emissions leakage, the assembly is cycled between room temperature (approximately <NUM>) and an elevated temperature (<NUM>) at the rate illustrated in Chart <NUM> below. Helium is used as the test fluid. Leakage is measured per mm of stem diameter.

<FIG> includes a graph <NUM> depicting assembly leakage <NUM> as a function of temperature cycle. The temperature profile <NUM> is adjusted according to Chart <NUM> above. Class AH sealing performance is indicated by line <NUM>. Class BH sealing performance is indicated by line <NUM>. As illustrated, the assembly leakage <NUM> performed within both Class AH and Class BH criteria. More specifically, the sample seal exhibited a fugitive emission measured leakage rate (mass flow) less than <NUM> × <NUM>-<NUM> mg*s-<NUM>*m-<NUM> per stem perimeter, as measured according to ISO <NUM>-<NUM>. The sample seal may exhibit the above leakage rate or better over endurance classes of CO1, CO2, and CO3.

In an embodiment, the annular seal is adapted to have a fugitive emission measured leakage rate (volumetric flow) less than <NUM> x <NUM>-<NUM> mbar*<NUM>*s-<NUM>*mm of stem, as measured according to ISO <NUM>-<NUM>. The measured leakage rate (volumetric flow) can be determined per mm of stem diameter through the stem seal system. In an embodiment, the annular seal is adapted to exhibit the above leakage rate or better over endurance classes of CO1 (<NUM> cycles), CO2 (<NUM> cycles), and CO3 (<NUM> cycles). Such performance is typically only achievable using bellow-type seals.

Claim 1:
An annular seal (<NUM>; <NUM>) comprising:
a first energized jacket (<NUM>; <NUM>) defining a first axial end (<NUM>) of the annular seal (<NUM>; <NUM>);
a plurality of seal rings (<NUM>) defining a second axial end (<NUM>) of the annular seal (<NUM>; <NUM>);
a second energized jacket (<NUM>; <NUM>) comprising a hub (<NUM>) and disposed between the first energized jacket (<NUM>; <NUM>) and the plurality of seal rings (<NUM>); and
a spacer (<NUM>; <NUM>) disposed between the first (<NUM>; <NUM>) and second (<NUM>; <NUM>) energized jackets, wherein the first energized jacket (<NUM>; <NUM>) comprises a first body (<NUM>) defining a volume (<NUM>) at least partially containing a first energizing element (<NUM>) having a generally "O" shaped cross-sectional profile, and wherein a seal ring of the plurality of seal rings (<NUM>) contacts the hub (<NUM>) of the second energized jacket (<NUM>; <NUM>) along a planar interface (<NUM>) disposed generally perpendicular to a central axis A of the annular seal (<NUM>; <NUM>).