Patent Description:
Face seals for fluid coupling assemblies are commonly used to sealingly connect together components in a fluid system. A face seal coupling assembly generally is one in which a sealing surface of one of the coupling members has a generally flat face disposed in a plane that is generally perpendicular to the central or longitudinal axis of the coupling member, and a seal carried by the other coupling member sealingly engages against the flat face of the first coupling member. In this type of fluid coupling assembly, the seal may be a conventional elastomeric O-ring seal that is retained in a groove in the second coupling member and provides a fluid seal when the coupling members are connected together. Such elastomeric O-ring seals may be selected in a known manner, examples of which are disclosed in <CIT> and <CIT>.

One common issue with elastomeric O-ring seals is that they are unsuitable for use in some severe service applications, such as hightemperature applications or conditions in which the elastomer lacks chemical compatibility with the external environment and/or internal fluid chemistry. As such, face seals made of metal are commonly used in such severe service applications. Some metal seals may include retaining features to better secure the metal seal against the coupling member. An example of such a metal face seal with retaining members is described in <CIT>.

The following documents may provide additional technical background to the present disclosure: <CIT> directed towards a metallic sealing device for valve; and <CIT> directed towards a hydraulic tubing fitting seal.

Although metal face seals of the type described above are suitable for use in many severe service applications, such metal seals may lack stiffness and may distort prior to assembly on the face coupling assembly. As such, the installer may have issues securing the metal face seal onto the coupling member and obtaining a suitable seal. The lack of stiffness and distortion of the metal seal also may render retaining features inadequate to secure the seal to the coupling member during the installation procedure. This issue is particularly problematic for larger diameter coupling designs. Although stiffer materials or thicker gauge material stock may address some of these concerns, such material selection is not practical for many applications.

At least one aspect according to the present disclosure provides a metal seal for a face seal coupling assembly that solves one or more problems of conventional metal face seal designs.

For example, according to at least one aspect, a metal seal for a face seal coupling assembly provides an angled outer annular portion that is designed to enhance stiffness of the seal body and improve the retaining force provided by one or more retaining members of the seal. The exemplary seal according to the present disclosure includes unique retaining members that improve over conventional designs.

According to an aspect, a metal seal for a flat face fluid coupling is provided as defined in appended claim <NUM>, including: an annular seal body defining a central axis and a central passage extending axially through the seal body along the central axis; and a plurality of seal retainers circumferentially spaced apart along a radially inner portion of the seal body; each of the plurality of seal retainers having a fixed end fixed to a radially inner portion of the seal body, a free end spaced from the seal body, and an intermediate portion extending between the free end and the fixed end, each of the plurality of seal retainers being configured to engage a retainer wall of the fluid coupling with a retaining force for securing the seal to the fluid coupling; wherein the annular seal body has opposite axially facing first and second flat annular sealing surfaces, and a radially outer annular angled portion that is inclined relative to the first flat annular sealing surface, the annular angled portion being configured to enhance stiffness around a circumference of the annular seal body, and the annular angled portion being configured to engage a face of the fluid coupling to generate a moment of force about a portion of each of the plurality of seal retainers for enhancing the retaining force of each of the plurality of seal retainers acting against the retainer wall of the fluid coupling.

According to another aspect, a fluid coupling assembly is provided as defined in appended claim <NUM>, including: a first face seal fluid coupling having a first flat sealing surface at a first end, a first fluid passage extending through the first end radially inwardly of the first flat sealing surface, and a threaded nut rotatable about the first end; a second face seal fluid coupling having: threads for threadedly engaging the threaded nut of the first fluid fitting; a second flat sealing surface at a second end of the second fluid coupling that faces toward the first flat sealing surface of the first fluid coupling, an annular face groove extending axially into the second end and axially away from the second flat sealing surface of the second fluid coupling, and a second fluid passage extending through the second end radially inwardly of the second flat sealing surface and the annular face groove; and a metal seal arranged between the first flat sealing surface and the second flat sealing surface, the metal seal comprising: an annular seal body defining a central axis and a central passage extending axially through the seal body along the central axis, the central passage being aligned with the first and second fluid passages of the fluid couplings; and retainers circumferentially spaced apart from each other about a radially inner portion of the annular seal body, each retainer having a fixed end fixed to the radially inner portion, a free end spaced from the seal body, and an intermediate portion extending between the free end and the fixed end, the retainers being configured to engage a surface of the annular face groove of the second fluid coupling; wherein the annular seal body has opposite axially facing first and second flat annular sealing surfaces in which the first annular sealing surface engages the first flat sealing surface of the first fluid coupling and the second annular sealing surface engages the second flat sealing surface of the second fluid coupling, and the annular seal body having an annular angled portion that is radially outward of the first and second flat annular sealing surfaces and is inclined relative to the first flat annular sealing surface in a direction radially outwardly and toward the second fluid coupling, the annular angled portion being configured to enhance stiffness around a circumference of the annular seal body, and being configured to engage a surface of the second fluid coupling to generate a moment of force that enhances retaining force of the retainers acting against the surface of the annular groove of the second fluid coupling.

The following description and the annexed drawings set forth certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features according to aspects of the invention will become apparent from the following detailed description when considered in conjunction with the drawings.

Referring initially to <FIG>, a conventional face seal fitting assembly according to <CIT> is shown, including a face seal fluid fitting <NUM> and a metal seal <NUM> that is capable of operating in extreme conditions. As shown, the conventional face seal fluid fitting <NUM> includes a first flat face seal fitting member <NUM>, a second flat face seal fitting member <NUM>, a sleeve <NUM>, a nut <NUM>, and the metal seal <NUM>, which are all arranged in coaxial alignment along a longitudinal axis <NUM>. The first fitting member <NUM>, second fitting member <NUM>, sleeve <NUM>, and nut <NUM> may each be generally cylindrical. An example of such fitting components may be of the type generally described in <CIT> and <CIT>, the disclosures of which are incorporated herein by reference. These fitting components may be stainless steel or other suitable material.

The first flat face seal fitting member <NUM> may be of any desired configuration, and in the illustrated embodiment is integrally formed on the free end <NUM> of a metal tube <NUM>. The free end <NUM> of the tube <NUM> may be deformed laterally outward or laterally away from the longitudinal axis <NUM> to form a generally flat laterally-extending flange or wall <NUM> having a generally smooth, flat, annular laterally-extending sealing surface <NUM> disposed in a plane substantially perpendicular to the longitudinal axis <NUM>, as illustrated. Alternatively, for example, the flat laterally-extending sealing surface <NUM> of the first fitting member <NUM> may be formed on a separate piece that is attached to the tube <NUM> in the manner generally illustrated in the above-referenced <CIT>, or in any other desired manner. The sleeve <NUM> is arranged on the tube <NUM> on the side of the flange or wall <NUM> opposite the sealing surface <NUM>. The nut <NUM> may include an annular flange <NUM> that engages the sleeve <NUM> and may have an exterior wrench flat surface <NUM> for engagement with a wrench (not shown) for tightening the nut <NUM> onto the second fitting member <NUM>.

The second flat face seal fitting member <NUM> may include a fitting member body <NUM> having a central passage <NUM>, an exterior wrench flat surface <NUM> for engagement with a wrench (not shown) during assembly, and an exterior threaded end surface <NUM>. A generally smooth, flat, annular, laterally-extending sealing surface <NUM> of the fitting member body <NUM> may be disposed in a plane generally perpendicular to the longitudinal axis <NUM>. The sealing surface <NUM> may be generally parallel to the surface <NUM>, and the surfaces <NUM> and <NUM> face in axially opposing directions toward one another.

An annular face groove or channel <NUM> may extend axially away from the sealing surface <NUM> into the body <NUM>. The channel <NUM> includes generally cylindrical laterally inner and outer side walls <NUM> and <NUM> and a bottom wall <NUM>. A retainer wall <NUM> extends laterally from the outer side wall <NUM> across a portion of the opening of the channel <NUM>. The retainer wall <NUM> includes a top surface <NUM> facing longitudinally away from the bottom wall <NUM> and a bottom or retaining surface <NUM> facing longitudinally toward the bottom wall <NUM> to thereby form a lip. The top and bottom surfaces <NUM> and <NUM> meet at a laterally innermost annular edge <NUM> of the retainer wall <NUM>. When the first fitting member <NUM>, second fitting member <NUM>, sleeve <NUM>, and nut <NUM> are used as a conventional O-ring face seal fitting, the retainer wall <NUM> retains an elastomeric O-ring (not shown) in the channel <NUM> prior to and during assembly of the fitting <NUM> in the manner described in the above-referenced <CIT> and <CIT>.

The conventional metal seal device <NUM> shown in <FIG> includes a generally flat annular seal body <NUM> having opposite axially facing annular sealing surfaces <NUM> and <NUM>, and a central passage <NUM> extending axially through the body <NUM> between the sealing surfaces <NUM> and <NUM>. The seal <NUM> further includes longitudinally extending retainers <NUM>. The body <NUM> and retainers <NUM> are of an integral one-piece construction. Each retainer <NUM> includes a fixed end <NUM> fixed to the annular seal body <NUM>, a free end <NUM> spaced longitudinally away from the sealing surfaces <NUM> and <NUM>, and an intermediate wall <NUM> extending between the fixed end <NUM> and free end <NUM>. The intermediate wall <NUM> is generally C-shaped with a generally smooth convex outer surface <NUM> facing laterally outwardly away from the longitudinal axis <NUM> and a corresponding concave inner surface <NUM> facing laterally inwardly toward the longitudinal axis <NUM>. In the assembled state, the convex outer wall <NUM> of each retainer <NUM> engages both the bottom or retaining surface <NUM> of the retainer wall <NUM> and the outer wall <NUM> of the channel <NUM>. The retainers <NUM> position and hold the seal <NUM> in proper alignment with the second fitting member <NUM>, so that the sealing surface <NUM> of the seal device <NUM> and the sealing surface <NUM> of the second fitting member <NUM> are aligned and engage one another before and during assembly of the second fitting member <NUM> and first fitting member <NUM>.

Although the metal seal <NUM> provides suitable positioning and retention for many applications, one issue with the metal seal <NUM> is that the relatively thin metal material can lack stiffness which allows the seal <NUM> to distort (e.g., twist) in an unloaded state prior to assembly on the fluid fitting <NUM>. This distortion can impact the retention functionality of the retainers <NUM> and can impact the ease of installation for the installer. This distortion issue becomes exacerbated with larger diameter fitting designs. The retainers <NUM> of the conventional metal seal <NUM> also may not provide adequate retaining force against the retainer wall of the fitting to prevent the seal <NUM> from being dislodged.

Turning to <FIG>, an exemplary face seal coupling assembly <NUM> according to an embodiment of the present disclosure is shown, including face seal fluid coupling <NUM> and metal seal <NUM>, in which the metal seal <NUM> solves one or more problems associated with the conventional metal seal <NUM> shown in <FIG>. The fluid coupling <NUM> is generally the same as the fluid fitting <NUM> described above in connection with <FIG>, and thus the same reference numerals refer to the same or similar parts. It is understood that although the fluid coupling <NUM> according to the present disclosure is shown as a fluid fitting, other flat face fluid couplings for interconnecting fluid-carrying conduits could be employed, such as SAE J518 / ISO <NUM> / ISO <NUM> type flanges having a flat face design, for example.

As shown in the illustrated embodiment, the metal seal <NUM> includes an annular seal body <NUM> having opposite axially facing annular sealing surfaces <NUM> and <NUM>, and a central passage <NUM> extending axially through the body <NUM> between the sealing surfaces <NUM> and <NUM>. The seal <NUM> further includes a plurality of retainers <NUM> (also referred to as retaining members) configured to engage a surface in the annular face groove <NUM> of the coupling <NUM> with a retaining force for securing the seal <NUM> to the fluid coupling <NUM>.

The retainers <NUM> are circumferentially spaced apart along a radially inner portion <NUM> of the seal body <NUM>, and may include two, three, four or more retainers <NUM>. Each retainer <NUM> includes a fixed end <NUM> fixed to the radially inner portion <NUM> of the seal body <NUM>, a free end <NUM> spaced from the seal body <NUM>, and an intermediate portion <NUM> extending between the free end <NUM> and the fixed end <NUM>. In the illustrated embodiment, the intermediate portion <NUM> (also referred to as an intermediate wall) extends axially toward the bottom surface <NUM> of the annular groove <NUM> and has a generally C-shaped cross-section. The C-shaped cross-section of the intermediate portion <NUM> is configured such that the concave side <NUM> of the C-shape faces radially inwardly and the convex side <NUM> of the C-shape faces radially outwardly. The C-shape of the intermediate portion <NUM> enables the retainer <NUM> to grab a radially protruding lip formed by the retainer wall <NUM> of the coupling <NUM>. The C-shape of the intermediate portion <NUM> also may provide a smooth cam surface that enables displacement of the intermediate portion <NUM> and the free end <NUM> radially inwardly when the metal seal <NUM> is being installed on and removed from the annular groove <NUM> of the fluid coupling <NUM>.

As shown, the annular seal body <NUM> also includes a radially outer annular angled portion <NUM> that is inclined at an angle (α) relative to the first and second flat annular sealing faces <NUM>, <NUM>. The outer annular angled portion <NUM> is configured to enhance stiffness around the circumference of the seal body <NUM> to thereby reduce deformation (e.g., twisting) of the seal <NUM>, which may be caused by residual stresses, external forces, or the like. Also as shown, the outer annular angled portion <NUM> of the seal <NUM> is configured to engage a radially outward face <NUM> of the fluid coupling <NUM>, which by virtue of the incline of the angled portion <NUM>, engages the face <NUM> with a force (F) that generates a moment (M) of force about a portion of the retainer <NUM>. This moment (M) of force results in a reaction force (Fr) at the interface between the retainer <NUM> and side wall <NUM> and/or retainer wall <NUM>. The additional reaction force (Fr) enhances the retaining force provided by the retainers <NUM>, thereby promoting a more active engagement and securement of the seal <NUM> with the coupling <NUM>.

As shown in the illustrated embodiment, the annular angled portion <NUM> continuously extends radially outwardly and axially toward the coupling <NUM> and terminates at a peripheral outer edge <NUM> of the seal <NUM>. In exemplary embodiments, the radially outer peripheral portion proximal the outer edge <NUM> of the seal <NUM> is configured to engage the face <NUM> of the coupling <NUM> to thereby increase the lever-effect and the moment (M) of force acting about the fixed end <NUM> of the retainer <NUM>, whereby the convex side <NUM> of the C-shaped intermediate portion <NUM> grips into the annular groove <NUM> at an underside of the lip of the retaining wall <NUM>. In addition, the radially outer peripheral portion proximal the outer edge <NUM> engage the coupling face <NUM> helps to minimize the edge <NUM> from overhanging the face <NUM> of the coupling <NUM> and potentially getting caught, as may be the case in the convention seal <NUM> design. As such, the exemplary seal <NUM> enables positioning radially in between two fixed coupling ends in narrow conditions, which is often the case in a face seal coupling assembly which usually has zero tube entry for allowing a straight tube with two flanged ends to position and couple together. The conventional seal <NUM>, on the other hand, has the overhanging outer edge that could be hit by the outer diameter corners of the flanges and pushed radially out of position. As such, the annular angled portion <NUM> of the seal <NUM> enables prevention of the collision with the flange outer diameter corners. Furthermore, because the metal seal body <NUM> may have resiliency (such as at transitional bend <NUM>), the engagement force (F) provided by the outer annular angled portion <NUM> may provide a spring-like preload and lever-action across the seal face <NUM> that further enhances the moment (M) of force and retaining force (Fr) of the retainers <NUM>.

The incline angle (α) and annular width (W1) of the outer annular angled portion <NUM> may be configured as needed to provide the desired moment (M) and/or retaining force (Fr) when interacting with the coupling <NUM> in a particular application. This may depend on factors such as the material chosen for the seal body <NUM>, the wall thickness (t) of the seal body <NUM>, the diameter of the coupling <NUM>, the annular width (W2) of the annular sealing surface(s) <NUM>, <NUM>, the lever-arm distance to the retainers <NUM>, or the like. The engagement face <NUM> of the coupling <NUM> may be perpendicular to the central axis <NUM>, or the engagement face <NUM> itself may have an inclined angle. The inclined angle (α) of the outer angled portion <NUM> may be about the same or greater than an inclined angle of the engagement face <NUM> of the coupling <NUM>. In exemplary embodiments, the angle (α) may be in a range from about <NUM>-degrees to about <NUM>-degrees (including all values, ranges and subranges with <NUM>-degree increments between the stated values), more particularly about <NUM>-degrees to about <NUM>-degrees, even more particularly about <NUM>-degrees. In exemplary embodiments, the annular width (W1) of the annular angled portion <NUM> is less than the annular width (W2) of the annular seal face <NUM>, such as a ratio (W1:W2) in a range from about <NUM>:<NUM> to about <NUM>:<NUM> (including all values, ranges and subranges with <NUM>-point increments between the stated values), or about <NUM>:<NUM> to about <NUM>:<NUM>, for example, such as about <NUM>:<NUM>.

The metal seal <NUM> may be made from any suitable metal or combination of metals. For example, the metal of the seal <NUM> may be capable to withstand temperatures in a range from -<NUM>°F to about <NUM>°F. An example of such metal may be stainless steel, such as <NUM> stainless. As shown, the seal body <NUM> (including seal faces <NUM>, <NUM> and outer angled portion <NUM>) and retainers <NUM> may be a unitary construction and may have a uniform wall thickness (t) for the respective parts <NUM>, <NUM> of the seal <NUM>. Such a metal seal <NUM> may be stamped from a metal blank with the outer angled portion <NUM> and retainers <NUM> then bent and formed into position. An exemplary wall thickness of the metal seal <NUM> may be in a range from about. <NUM>-inches to about <NUM>-inches (including all values, ranges and subranges with. <NUM>-inch increments between the stated values). The metal seal <NUM> may be sized for standard-sized couplings, such as fittings, flanges, or the like, that are in a range from <NUM>/<NUM>-inch to <NUM>-inch, for example.

In some exemplary embodiments, one or more of the retainers <NUM> are configured as resilient tabs or fingers that displace to fit over the retainer wall <NUM> and spring back to engage under the lip of the retainer wall <NUM>. Alternatively or additionally, one or more of the retainers <NUM> may be configured to be plastically deformed by a tool or by hand to actively engage the retainer wall <NUM>. The plastic deformation of the retainers <NUM> combined with the enhanced retaining force resulting from the lever-effect provided by outer annular angled portion <NUM> the moment (M) may provide a more active and secure engagement of the seal <NUM> with the coupling <NUM>.

Turning to <FIG>, another exemplary face seal coupling assembly <NUM> according to an embodiment of the present disclosure is shown, including face seal fluid coupling <NUM> and metal seal <NUM>. The fluid coupling <NUM> is the same as the fluid coupling described above, and consequently the same reference numerals are used. The metal seal <NUM> is substantially the same or similar to the above-referenced metal seal <NUM>, and consequently the same reference numerals but in the <NUM>-series are used to denote structures corresponding to similar structures in the metal seals <NUM>, <NUM>. In addition, the foregoing description of the metal seal <NUM> is equally applicable to the metal seal <NUM>, except as noted below. Moreover, it is understood that aspects of the metal seals <NUM>, <NUM> may be substituted for one another or used in conjunction with one another where applicable.

Referring to <FIG>, a partial cross-sectional perspective view of the metal seal <NUM> fully installed on the coupling <NUM> is shown. Similarly to the seal <NUM>, the metal seal <NUM> includes an annular seal body <NUM> having opposite axially facing annular sealing surfaces <NUM> and <NUM>, and a central passage <NUM> extends axially through the body <NUM> between the sealing surfaces <NUM> and <NUM>. The seal <NUM> further includes a plurality of retainers <NUM> configured to engage a surface in the annular face groove <NUM> of the coupling <NUM>, such as the retainer wall <NUM> and/or sidewall <NUM>, for securing the seal <NUM> to the fluid coupling <NUM>. The seal body <NUM> also includes a radially outer annular angled portion <NUM> that is inclined at an angle relative to the first and second flat annular sealing faces <NUM>, <NUM>. As described above, the outer annular angled portion <NUM> may be configured to enhance stiffness around the circumference of the seal body <NUM> and/or may enhance the retaining force of the retainers <NUM> by generating a moment of force about the retainers <NUM>. The incline angle (α) of the angled portion <NUM>, the annular width or ratio of the angled portion <NUM>, the wall thickness of the seal <NUM>, type of material, etc. may be the same as that described above in connection with seal <NUM>.

The retainers <NUM> are circumferentially spaced apart along a radially inner portion <NUM> of the seal body <NUM>, and may include two, three, four or more retainers <NUM>. Each retainer <NUM> includes a fixed end <NUM> fixed to the radially inner portion of the seal body <NUM>, a free end <NUM> spaced from the seal body <NUM>, and an intermediate portion <NUM> extending between the free end <NUM> and the fixed end <NUM>. In the illustrated embodiment, the intermediate portion <NUM> (also referred to as intermediate wall) extends axially toward the bottom surface <NUM> of the annular groove <NUM> and forms a hook having a general angular C-shaped cross-section, which includes a V-shaped hook portion. The angular C-shaped intermediate portion <NUM> in this embodiment has the convex side <NUM> facing radially inwardly and the concave side <NUM> facing radially outwardly, and thus forms the hook whereby the free end <NUM> can engage the underside of the radially inwardly protruding lip of the retainer wall <NUM> to secure the seal <NUM> in place. In the illustrated embodiment, the retainers <NUM> are configured to be plastically deformed by a tool or by hand to actively engage the retainer wall <NUM>.

Referring to <FIG>, an installation of the metal seal <NUM> onto the coupling <NUM> with an exemplary tool <NUM> is shown. As shown, the tool <NUM> includes a receptacle <NUM> that receives an end portion of the coupling <NUM>. The receptable <NUM> includes an annular shoulder <NUM> that engages the end face of the coupling <NUM>. A plunger <NUM> is adapted to fit within the annular groove <NUM> of the coupling <NUM> and displace and plastically deform the retainers <NUM> to latch onto the lip of the retainer wall <NUM>. The plunger <NUM> may be spring-biased with a spring <NUM>. <FIG> shows the seal <NUM> in an initial state in which the retainers <NUM> are not bent, and <FIG> shows an installed state by the tool <NUM> in which the retainers <NUM> (e.g., hook tabs) are plastically deformed into the installed state to grab onto the lip of the retainer wall <NUM>.

Turning to <FIG>, another exemplary face seal coupling assembly <NUM> according to an embodiment of the present disclosure is shown, including face seal fluid coupling <NUM> and metal seal <NUM>. The fluid coupling <NUM> is the same as the fluid coupling described above, and consequently the same reference numerals are used. The metal seal <NUM> is substantially the same or similar to the above-referenced metal seals <NUM>, <NUM> and consequently the same reference numerals but in the <NUM>-series are used to denote structures corresponding to similar structures in the metal seals <NUM>, <NUM>, <NUM>. In addition, the foregoing description of the metal seals <NUM>, <NUM> is equally applicable to the metal seal <NUM>, except as noted below. Moreover, it is understood that aspects of the metal seals <NUM>, <NUM>, <NUM> may be substituted for one another or used in conjunction with one another where applicable.

Referring to <FIG>, a partial cross-sectional perspective view of the metal seal <NUM> fully installed on the coupling <NUM> is shown. Similarly to the seals <NUM> and <NUM>, the metal seal <NUM> includes an annular seal body <NUM> having opposite axially facing annular sealing surfaces <NUM> and <NUM>, and a central passage <NUM> extends axially through the body <NUM> between the sealing surfaces <NUM> and <NUM>. The seal <NUM> further includes a plurality of retainers <NUM> configured to engage a surface of the annular face groove <NUM> of the fluid coupling <NUM> with a retaining force for securing the seal <NUM> to the fluid coupling <NUM>. In the illustrated embodiment, the retainers <NUM> are configured to engage a radially inner sidewall <NUM> of the annular groove <NUM>, which serves as a retainer wall of the coupling <NUM> in this embodiment. The seal body <NUM> also includes a radially outer annular angled portion <NUM> that is inclined at an angle (α) relative to the first and second flat annular sealing faces <NUM>, <NUM>. As described above, the outer annular angled portion <NUM> may be configured to enhance stiffness around the circumference of the seal body <NUM> and/or may enhance the retaining force of the retainers <NUM> by generating a moment of force about the retainers <NUM>. The incline angle (α) of the angled portion <NUM>, the annular width or ratio of the angled portion <NUM>, wall thickness of the seal, type of material, etc. may be the same as that described above in connection with seal <NUM> and/or <NUM>.

The retainers <NUM> are circumferentially spaced apart along a radially inner portion of the seal body <NUM>, and may include two, three, four or more retainers <NUM>. Each retainer <NUM> includes a fixed end <NUM> fixed to the radially inner portion of the seal body <NUM>, a free end <NUM> spaced from the seal body <NUM>, and an intermediate portion <NUM> extending between the free end <NUM> and the fixed end <NUM>. In the illustrated embodiment, the intermediate portion <NUM> (also referred to as intermediate wall) extends laterally across the groove <NUM> toward the radially inner sidewall <NUM> and forms a general C-shaped cross-section. The C-shaped intermediate portion <NUM> in this embodiment has the convex side <NUM> facing axially toward the bottom <NUM> of the groove <NUM> and the concave side <NUM> facing upwardly out of the groove <NUM>. In the illustrated embodiment, the retainer <NUM> is adapted to form an interference fit in the groove <NUM> so that the free end <NUM> engages the inner wall <NUM> with a retaining force. The retainers <NUM> may be configured to be resilient to provide a spring force as a component of the retaining force; or the retainers <NUM> may be plastically deformed to form the interference fit.

Referring to <FIG>, an installation of the metal seal <NUM> onto the coupling <NUM> with an exemplary tool <NUM> is shown. The tool <NUM> may be the same as the tool described above, and consequently the same reference numerals are used. <FIG> shows the seal <NUM> in an initial state in which the retainers <NUM> have a wider extent than the groove <NUM> and thus overlap the radially inner wall <NUM>. <FIG> shows an installed state by the tool <NUM> in which the retainers <NUM> are pushed into the groove <NUM> and the free ends <NUM> engage the radially inner wall <NUM>.

Turning to <FIG>, another exemplary face seal coupling assembly <NUM> according to an embodiment of the present disclosure is shown. The coupling assembly <NUM> shares similarities with the foregoing face seal coupling assemblies <NUM>, <NUM>, <NUM> and consequently the same reference numerals but in the <NUM>-series are used to denote structures corresponding to similar structures in the face seal coupling assemblies. In addition, the foregoing description of the face seal coupling assemblies <NUM>, <NUM>, <NUM> is equally applicable to the face seal coupling assembly <NUM>, except as noted below. Moreover, it is understood that aspects of the face seal coupling assemblies <NUM>, <NUM>, <NUM>, <NUM> may be substituted for one another or used in conjunction with one another where applicable.

In the illustrated embodiment, the face seal coupling assembly <NUM> is configured as a flange-style face seal coupling assembling, including a tube <NUM> (or tube end <NUM>) having a radially outwardly protruding shoulder <NUM>, a flat annular sealing surface <NUM>, and an annular face groove or channel <NUM> extending into the surface <NUM>. The annular groove <NUM> in the sealing surface <NUM> may be constructed the same as the above-described annular groove <NUM>, including cylindrical laterally inner and outer side walls <NUM>, <NUM>; bottom wall <NUM>; and retainer wall <NUM>. A flange adapter <NUM> operatively couples to the tube end <NUM> via an interface <NUM>, which is shown via radially overlapping shoulders of the tube end <NUM> and flange adapter <NUM> in the illustrated embodiment, but which also may include a tapered interface, or the like. In addition, the flange adapter <NUM> includes one or more fastening receivers (such as through-holes or threaded bores) that receive one or more fasteners <NUM> (e.g., bolts) for attaching the flange adapter <NUM> to the tube end <NUM>. In the illustrated embodiment, the flange adapter <NUM> is attached to a manifold block <NUM> via the fasteners <NUM> to form a continuous fluid passage <NUM>; although it is understood that the tube end <NUM> may be operatively coupled to another tube end via another flange adapter or the like.

As shown, a metal seal <NUM> is disposed on the sealing surface <NUM> between the tube end <NUM> and a sealing surface of the manifold block <NUM>. In the illustrated embodiment, the metal seal <NUM> is substantially the same as the metal seal <NUM> described above, and includes an annular seal body <NUM>, one or more retainers <NUM> having a fixed end <NUM> fixed to a radially inner portion of the seal body <NUM>, a free end <NUM> spaced from the seal body <NUM>, and an intermediate portion <NUM> extending between the free end and the fixed end. Similarly to the seal <NUM>, the seal <NUM> has the at least one seal retainer <NUM> engaging the retainer wall <NUM> with a retaining force for securing the seal <NUM> to the fluid coupling. Also as with the seal <NUM>, the seal <NUM> includes a radially outer annular angled portion <NUM> that is inclined at an angle relative to first and second flat annular sealing faces, wherein the outer annular angled portion <NUM> is configured to enhance stiffness around the circumference of the seal body and is configured to engage a radially outward face <NUM> of the tube end <NUM> to generate a moment of force that enhances the retaining force.

Exemplary face seal coupling assemblies including exemplary metal face seals have been described herein.

As used herein, an "operative connection," or a connection by which entities are "operatively connected," is one in which the entities are connected in such a way that the entities may perform as intended. An operative connection may be a direct connection or an indirect connection in which an intermediate entity or entities cooperate or otherwise are part of the connection or are in between the operatively connected entities. An operative connection or coupling may include the entities being integral and unitary with each other.

It is to be understood that terms such as "top," "bottom," "upper," "lower," "left," "right," "front," "rear," "forward," "rearward," and the like as used herein may refer to an arbitrary frame of reference, rather than to the ordinary gravitational frame of reference.

It is to be understood that all ranges and ratio limits disclosed in the specification and claims may be combined in any manner. It is to be understood that unless specifically stated otherwise, references to "a," "an," and/or "the" may include one or more than one, and that reference to an item in the singular may also include the item in the plural.

The term "about" as used herein refers to any value which lies within the range defined by a variation of up to ±<NUM>% of the stated value, for example, ±<NUM>%, ± <NUM>%, ± <NUM>%, ± <NUM>%, ± <NUM>%, ± <NUM>%, ± <NUM>%, ± <NUM>%, ± <NUM>%, ±<NUM> %, ±<NUM> %, or ±<NUM>% of the stated value, as well as values intervening such stated values.

The phrase "and/or" should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the "and/or" clause, whether related or unrelated to those elements specifically identified unless clearly indicated to the contrary. Thus, as a non-limiting example, a reference to "A and/or B," when used in conjunction with open-ended language such as "comprising" can refer, in one embodiment, to A without B (optionally including elements other than B); in another embodiment, to B without A (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc..

The word "or" should be understood to have the same meaning as "and/or" as defined above. Only terms clearly indicated to the contrary, such as "only one of" or "exactly one of," may refer to the inclusion of exactly one element of a number or list of elements.

The transitional words or phrases, such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," and the like, are to be understood to be open-ended, i.e., to mean including but not limited to.

Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a "means") used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.

In exemplary embodiment(s), the intermediate portion of the at least one retainer has a C-shaped cross-section including a concave side and a convex side, the intermediate portion being configured to extend laterally across an annular face groove in the fluid coupling such that the convex side faces axially toward a bottom of the annular face groove and the concave side faces axially away from the bottom of the annular face groove, and wherein the at least one retainer is configured such that the free end is engageable with a radially inner wall of the annular face groove to thereby hold the seal in place relative to the fluid coupling.

In exemplary embodiment(s), a combination or assembly including the seal according to any of the foregoing with a flat face seal fluid coupling is provided, in which the flat face seal fluid coupling having: a first end with a flat sealing surface engaging one of the first or second flat annular sealing surfaces of the metal seal, an annular face groove extending axially into the first end of the coupling member and axially away from the sealing surface of the coupling member, and a retainer wall extending circumferentially around the annular face groove.

In exemplary embodiment(s), the retainer wall extends circumferentially around the annular face groove adjacent to the coupling member sealing surface, the retainer wall having an inner surface facing axially away from the seal body and an outer surface abutting the seal body.

In exemplary embodiment(s), the intermediate portion of the at least one retainer of the seal engages the inner surface of the retainer wall.

In exemplary embodiment(s), the free end of the at least one retainer of the seal engages the inner surface of the retainer wall.

In exemplary embodiment(s), the retainer wall forms a radially inner surface of the annular face groove, and the intermediate portion of the at least one retainer is configured to extend laterally across the annular face groove such that the intermediate portion or the free end of the at least one retainer engages the retainer wall.

According to another aspect, a fluid coupling assembly includes: a first face seal fluid coupling having a first flat sealing surface at a first end, a first fluid passage extending through the first end radially inwardly of the first flat sealing surface, and a threaded nut rotatable about the first end; a second face seal fluid coupling having: threads for threadedly engaging the threaded nut of the first fluid coupling; a second flat sealing surface at a second end of the second fluid coupling that faces toward the first flat sealing surface of the first fluid coupling, an annular face groove extending axially into the second end and axially away from the second flat sealing surface of the second fluid coupling, and a second fluid passage extending through the second end radially inwardly of the second flat sealing surface and the annular face groove; and a metal seal arranged between the first flat sealing surface and the second flat sealing surface, the metal seal comprising: an annular seal body defining a central axis and a central passage extending axially through the seal body along the central axis, the central passage being aligned with the first and second fluid passages of the fluid coupling; and retainers circumferentially spaced apart from each other about a radially inner portion of the annular seal body, each retainer having a fixed end fixed to the radially inner portion, a free end spaced from the seal body, and an intermediate portion extending between the free end and the fixed end, the retainers being configured to engage a surface of the annular face groove of the second fluid coupling; wherein the annular seal body has opposite axially facing first and second flat annular sealing surfaces in which the first annular sealing surface engages the first flat sealing surface of the first fluid coupling and the second annular sealing surface engages the second flat sealing surface of the second fluid coupling, and the annular seal body having an annular angled portion that is radially outward of the first and second flat annular sealing surfaces and is inclined relative to the first flat annular sealing surface in a direction radially outwardly and toward the second fluid coupling, the annular angled portion being configured to enhance stiffness around a circumference of the annular seal body, and being configured to engage a surface of the second fluid coupling to generate a moment of force that enhances retaining force of the retainers acting against the surface of the annular groove of the second fluid coupling.

According to another aspect, a metal seal for a flat face seal fluid coupling, includes: a generally flat annular seal body defining a central axis and a central passage extending axially through the seal body along the central axis and between axially oppositely facing first and second generally flat annular sealing surfaces, the annular seal body having an outer annular angled portion; a longitudinally extending retainer, the retainer having: a fixed end rigidly fixed to the seal body, a free end axially spaced from the seal body, and an intermediate wall extending between the free end and the fixed end, the intermediate wall extending axially away from the fixed end, wherein the intermediate wall has a generally C-shaped cross section, the concave side of the C-shaped wall faces radially inward, and the convex side of the C-shaped wall faces radially outward and provides a smooth cam surface to displace the intermediate wall and the free end radially inwardly when the metal seal is being installed on and removed from a face seal coupling member, wherein the angled surface extends longitudinally toward the free end of the retainer.

According to another aspect, a metal seal for a flat face seal fluid coupling, includes: a generally flat annular seal body defining a central axis and a central passage extending axially through the seal body along the central axis and between axially oppositely facing first and second generally flat annular sealing surfaces; a longitudinally extending retainer, the retainer having: a fixed end rigidly fixed to the seal body, a free end axially spaced from the seal body, and an intermediate wall extending between the free end and the fixed end, the intermediate wall extending axially away from the fixed end, wherein the intermediate wall has a generally C-shaped cross section, the concave side of the C-shaped wall faces axially away from the fixed end, and the convex side of the C-shaped wall faces axially toward the fixed end and provides a surface for a tool to displace the intermediate wall and the free end radially inwardly when the metal seal is being installed on a face seal coupling member, wherein the retainer has only a single curve between the free end and the fixed end so as to form an overall C-shape.

In exemplary embodiments, the metal seal further includes a conical portion on an inner diameter of the metal seal.

Claim 1:
A metal seal (<NUM>; <NUM>; <NUM>) for a flat face fluid coupling (<NUM>), comprising:
an annular seal body (<NUM>; <NUM>; <NUM>) defining a central axis and a central passage (<NUM>; <NUM>; <NUM>) extending axially through the seal body (<NUM>; <NUM>; <NUM>) along the central axis; and
a plurality of seal retainers (<NUM>; <NUM>; <NUM>) circumferentially spaced apart along a radially inner portion (<NUM>; <NUM>; <NUM>) of the seal body;
each of the plurality of seal retainers (<NUM>; <NUM>; <NUM>) having a fixed end (<NUM>; <NUM>; <NUM>) fixed to a radially inner portion (<NUM>; <NUM>; <NUM>) of the seal body, a free end (<NUM>; <NUM>; <NUM>) spaced from the seal body (<NUM>; <NUM>; <NUM>), and an intermediate portion (<NUM>; <NUM>; <NUM>) extending between the free end (<NUM>; <NUM>; <NUM>) and the fixed end (<NUM>; <NUM>; <NUM>), each of the plurality of seal retainers (<NUM>; <NUM>; <NUM>) being configured to engage a retainer wall (<NUM>) of the fluid coupling with a retaining force for securing the seal (<NUM>; <NUM>; <NUM>) to the fluid coupling (<NUM>);
wherein the annular seal body (<NUM>; <NUM>; <NUM>) has opposite axially facing first and second flat annular sealing surfaces (<NUM>, <NUM>; <NUM>, <NUM>; <NUM>, <NUM>), and characterised in that the annular seal body (<NUM>; <NUM>; <NUM>) further has a radially outer annular angled portion (<NUM>; <NUM>; <NUM>) that is inclined relative to the first flat annular sealing surface (<NUM>; <NUM>; <NUM>), the annular angled portion (<NUM>; <NUM>; <NUM>) being configured to enhance stiffness around a circumference of the annular seal body (<NUM>; <NUM>; <NUM>), and the annular angled portion (<NUM>; <NUM>; <NUM>) being configured to engage a face (<NUM>) of the fluid coupling to generate a moment of force about a portion of each of the plurality of seal retainers (<NUM>; <NUM>; <NUM>) for enhancing the retaining force of each of the plurality of seal retainers (<NUM>; <NUM>; <NUM>) acting against the retainer wall (<NUM>) of the fluid coupling.