Abstract:
Device, system, and method are described directed to seal assemblies with support to reduce seal extrusion under high to very high pressure changes due to repeated piston reciprocating movement. In some examples, concave features are incorporated on the inner and outer edges of support and backup ring elements to support and hug the preceding element and constrain extrusion, as well as utilizing multiple contact points on certain elements in order to reduce friction against the dynamic surface. The seal assemblies described herein can also incorporate bearing surfaces to reduce damage to seal ID due to off-axis floating rod, such as incorporating one or more multi-point contacts to reduce friction.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This is a regular utility application of provisional application No. 61/524,844, filed Aug. 18, 2011, the contents of which are expressly incorporated herein by reference. 
     
    
     FIELD OF ART 
       [0002]    Aspects of the present device, system, and method relate to seals for sealing a dynamic surface and a static surface, for example spring energized seal assemblies for reciprocating applications in which a shaft reciprocates back-and-forth. 
       BACKGROUND 
       [0003]    A seal for a reciprocating application is typically used to seal liquid media and designed to be retained between a static surface and a dynamic surface, where the dynamic surface is translated back-and-forth in an axial direction, generating pulsating pressure. 
         [0004]    Typical seal applications in which seals make such dynamic contact include reagent dispensing, and syringe pumps generating low to high or ultra high pressure, etc., such as several hundred pounds of pressure to several thousand pounds of pressure. In such applications, seals can deform or extrude due to the pulsating pressure. 
         [0005]    Past solutions for such conditions include the use of rectangular and tapered support rings to fit within specialized retaining glands to try to block seal material extrusion. However, past solutions do not always support seal extrusion as well as prevent side-loading to the seal lip in contact with the dynamic surface of the piston. 
       SUMMARY OF EMBODIMENTS 
       [0006]    Aspects of the present device, system, and method include provisions for minimizing gaps between the reciprocating piston or shaft and elsewhere within a sealing box where a seal ring can flow or be pushed due to high system pressure to minimize flowable space for seal material extrusion. 
         [0007]    In one example, concave features on the inner and outer edges of support and backup elements or rings are provided to support and hug the preceding element to constrain extrusion. 
         [0008]    In another example, multiple contact points on certain elements of the seal assembly are provided to reduce friction against the dynamic surface, such as on the support ring and/or the backup ring. 
         [0009]    In still another example, interconnecting axial elements are provided between seal components to minimize separation during installation and use. In some examples, these interconnecting axial elements are support feet without mechanical engagement, such as detents or latches. 
         [0010]    In still yet another example, radial centering of the seal assembly along its exterior perimeter is provided to center the assembly relative to the seal holding box. For example, an energizer may be incorporated so that the backup ring or the support ring can also function a bearing. 
         [0011]    The device, system, and method are directed to support and reduce seal extrusion under extreme pressure changes due to repeated piston reciprocating movement by incorporating concave features on the inner and outer edges of support and backup ring elements to support and hug the preceding element and constrain extrusion, as well as utilizing multiple contact points on certain elements in order to reduce friction against the dynamic surface. The seal assemblies also include, to reduce damage to seal ID of an off-axis floating rod, a bearing surface on the rod, and multi-points of contact, to reduce friction. 
         [0012]    An assembly in accordance with aspects of the present disclosure can comprise at least two components wherein at least one component is a sealing ring and at least one component is a rigid support ring or a backup ring; the at least one of the rigid support ring or the backup ring comprises a concave interface feature and the sealing ring comprises matching a convex surface on an outer face feature to accept, one another when in direct contact with one another. 
         [0013]    In an example, the seal assembly comprises both a rigid support ring and a backup ring; and wherein the backup ring comprises a support foot, the rigid support ring comprises a support foot, and the seal ring comprises an inside axial lip extension for contacting a dynamic shaft and an outside radial lip extension for contacting a holding bore. 
         [0014]    A more specific feature of the seal assembly can include a groove on the backup ring having an energizer, spring or elastomer disposed therein. 
         [0015]    A material selection for the sealing ring or element can include PTFE, polyethylene, PTFE composition, or polyethylene composition. 
         [0016]    In embodiments with a spring, the spring can be at least one of a canted coil spring, a ribbon spring, or a V-spring. 
         [0017]    In another embodiment, the seal ring comprises an outer flange and an inner flange and a center channel section comprising a width located therebetween and wherein the support ring comprises a width measure from a groove to a surface that contacts the seal ring that is about 90% to about 150% of the width of the center channel section of the seal ring. 
         [0018]    A further aspect of the present disclosure is a method for manufacturing a seal assembly. In some embodiments, the method can comprise the steps of providing at least two mating components: wherein at least one component is a sealing ring and at least one component is a rigid support ring or a backup ring. The at least one of the rigid support ring or the backup ring can comprise a concave interface feature and the sealing ring can comprise a matching convex surface on an outer face feature to accept one another. The method can further comprise the step of placing the sealing ring in direct contact with the rigid support ring or the backup ring so that the convex surface on the sealing ring directly contacts the concave interface feature on the rigid support ring or the backup ring. 
         [0019]    In some embodiments, the method includes providing both the rigid support ring and the backup ring. 
         [0020]    In yet other embodiments, the method includes providing a groove on the backup ring and placing a canted coil spring in the groove. 
     
    
     
       SUMMARY OF THE DRAWINGS 
         [0021]      FIG. 1  is a schematic cross-sectional side view of a seal assembly provided in accordance with aspects of the present device, system, and method; 
           [0022]      FIG. 2  is a schematic cross-sectional side view of an alternative seal assembly provided in accordance with aspects of the present device, system, and method; and 
           [0023]      FIG. 3  is a schematic cross-sectional side view of another alternative seal assembly provided in accordance with aspects of the present device, system, and method. 
           [0024]      FIG. 4  is a schematic cross-sectional side view of yet another alternative seal assembly provided in accordance with aspects of the present device, system, and method. 
           [0025]      FIG. 5  is a schematic cross-sectional side view of still yet another alternative seal assembly provided in accordance with aspects of the present device, system, and method. 
           [0026]      FIG. 6  is a schematic process flow diagram depicting a method for manufacturing or for using a seal assembly provided in accordance with aspects of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    The detailed description set forth below in connection with the appended drawings is intended as a description of the presently preferred embodiments of seal assemblies provided in accordance with aspects of the present device, system, and method and is not intended to represent the only forms in which the present device, system, and method may be constructed or utilized. The description sets forth the features and the steps for constructing and using the seal assemblies of in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and structures may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the disclosure. As denoted elsewhere herein, like element numbers are intended to indicate like or similar elements or features. 
         [0028]    With reference to  FIG. 1 , a cross-sectional view of a seal assembly  30  provided in accordance with aspects of the present device, system, and method is shown. The seal assembly  30  is understood to be annular in shape with only half of the seal assembly shown from the centerline of the shaft. The seal assembly  30  comprises a number of seal components including a rigid backup ring  32 . In one example, the rigid backup ring  32  is made from a high modulus high temperature polymer material, a ferrous, or non-ferrous metal, such as PEEK (polyetheretherketone), PET (polyethylene terephthalate). PEK (polyetherketone), steel or stainless steel. The high modulus material of the backup ring  32  acts as a support for the support ring  34  to reduce material extruding into radial gap(s) under high pressure. In one embodiment, the rigid backup ring is generally rectilinear, i.e., rectangular, with an extended support foot extending towards a seal ring, as further discussed below. In another embodiment, the rigid backup ring is generally rectilinear and without a support foot. 
         [0029]    The rigid support ring  34 , located next to the rigid backup ring  32 , is made from a high modulus high temperature polymer material, a ferrous, or non-ferrous metal. The high modulus material of the support ring  34  supports a rear portion of the seal ring  36  to reduce material extruding into radial gap(s) under high pressure. As used herein, a front, front facing, or front portion is a structure or location that faces or is closest to the pressure region  8  of the seal chamber and the rear, rear facing, or rear portion is a structure or location that is remote from the pressure region, such as closest to the atmospheric region  10 . In one embodiment, the support ring is generally rectilinear, i.e., rectangular, with an extended support foot extending towards a seal ring, as further discussed below. Where a support foot is incorporated for the backup ring, a recessed section is provided on the rear facing side of the support ring. 
         [0030]    The seal ring  36  has an inner seal flange  55   a  comprising a seal or sealing lip  54  for sealing against a shaft  60 , an outer seal flange  55   b  comprising a flange lip  57 , and a center channel section  27  having a width or thickness measured along the direction of the shaft centerline, and a spring cavity  59  for retaining a spring energizer  38 , which exerts a spring force on the seal lip  54  to maintain a sealing force against the shaft  60  and against the outer flange  55   b  to seal against the interior surface of the gland or seal housing  58 , as further discussed below. Use of the spring energizer allows the seal assembly to maintain its seal against the shaft even under low pressure or vacuum where system pressure does not sufficiently force the inner and outer seal flanges  55   a ,  55   b  to seal against adjacent surfaces. The seal ring may be made from a PTFE material. In other embodiments, the seal ring may be made from a polyethylene, a PTFE composition, or a polyethylene composition 
         [0031]    In one example, the inner face (IF) feature  40  of the rigid support ring  34 , which is at the interface of the support ring  34  and the seal ring  36  and is inside relative to the atmosphere  10 , has a concave geometry to receive the seal ring  36  and supports and reduces seal ring  36  material extrusion under high pressure. The seal ring  36  has a convex corresponding surface feature for mating with the concave geometry of the support ring  34 . The interface  40  acts as a net or catcher to capture and retain the seal ring within the confine of the concave surface. 
         [0032]    The IF feature  42  of the rigid backup ring  32 , which is at the interface of the support ring  34  and the backup ring  32 , has a concave geometry that receives the rigid support ring  34  and supports and reduces rigid support ring material extrusion under high pressure. The IF feature  42  of the rigid backup ring  32  supports the outer face (OF) feature  12  of the support ring  34 . The concave surface  42 , which is concave in the direction of the outside atmosphere  10 , may be slightly concave such that the surface is not generally flat, as further discussed below. 
         [0033]    In one example, closer to the inside diameter of the rigid backup ring  32 , a concave feature  44  is configured to cradle the inside surfaces at the OF feature  12  of the rigid support ring  34  to reduce material extrusion. As shown, the concave surface  44  comprises a generally flat section  44   a  and a slant section  44   b . In one example, the generally flat section  44   a  and the slant section  44   b  directly contact the support ring and wherein the flat section  44   a  has a thickness or width measured in the direction of the shaft centerline that is equal to or greater than the width of the center channel section  27  of the sealing ring  36  to support the sealing ring against extrusion, as further discussed below. In one example, the thickness or width of the backup ring  32  is about 300% or larger than the width of the center channel section  27  of the seal ring  36 . The support ring  34  similarly has a thickness measured in the direction of the shaft centerline that is 80% to about 200% larger than the width of the center channel section of the seal ring. The support ring  34  and the seal ring  36  preferably abut or contact one another without any intervening mechanical engagement therebetween, such as detents or latches. This allows the two components to freely float as they experience pressure exerted by the system and not be hung up or trapped due to the detents or latches. 
         [0034]    A support foot  46  is provided on the backup ring  32  to support a recessed section  47  on the OF feature  12  of the rigid support ring  34 . The support foot  46  is provided at the IF feature  42  of the rigid backup ring  32  to reduce material extrusion on the support ring  34 , which reduces material extrusion on the seal ring  36 , from contacting the shaft. For example, the support foot  46  provides support for sections or parts of the support ring  34  that may tend to bulge or deflect, such as extrude, due to the high pressure and/or the reciprocating shaft  60 . As shown, the support foot  46  engages a recessed section  47  of the support ring. 
         [0035]    In one example, the interface feature  40  of the support ring  42  comprises a concave feature  48  for cradling the outer face feature of the seal ring  36  to reduce seal ring material extrusion. In one exemplary embodiment, the concave feature  48  is a bend formed on the IF feature  40  of the rigid support ring  34 . As shown, the concave feature  48  comprises a generally flat section  48   a  and a slant section  48   b . The rigid support ring  34  extends beyond the bend near the concave feature  48  to define a support foot  52  for supporting a recess section  35  of the seal ring  36 . Thus, an aspect of the present embodiment is a seal assembly comprising a seal ring, a support ring, and a backup ring, and wherein a support foot on the support ring projects into a recessed section on the seal ring and a support foot on the backup ring projects into a recessed section on the support ring. Preferably, the contacts between the three components are direct and within any detents or latches in between so that they are free to move or rotate to conform to the force or system pressure. 
         [0036]    In one example, the support foot  52  on the rigid support ring  34  is provided with multi-point contacts  50  within the inside diameter (ID) of the rigid support ring  34  to reduce drag and to provide a bearing surface to guide the rod or shaft  60 . The multi-point contact  50  on the support foot  52  may be formed by providing a recessed section  50   c  to create anon-contact region between two contact points  50   a ,  50   b . Thus, two contact points are spaced about a non-contact point or region  50   c . There may be more than one multi-point contacts and on both the support ring and the backup ring. In other examples, multiple recessed sections are provided between contact sections to create multiple contact regions. The configuration of the support foot  52  provides support for the seal ring  36  and reduces material contacting the shaft, such as by providing recessed sections between contact sections to provide multi-point contacts instead of a single line contact. The support foot  52  having multi-point contacts reduces friction compared to a support foot with a line contact without a recess. The support foot is also understood to provide support for the seal ring  36  against unwanted extrusion. 
         [0037]    In one embodiment, the support foot  52  on the rigid support ring  34  extends further radially inwardly towards the axis of the shaft or rod  60  than the support foot  46  on the backing ring  32 . In other words, the support foot  52  on the support ring is longer in the axial direction than the support foot  46  on the backup ring. The support foot  52  on the support ring also incorporates at least one multi-point contact  50  to minimize flowable gap or space. This configuration is provided so that any gap between the shaft  60  and the seal assembly is minimized or reduced by the support foot  52  to thereby support the seal ring  36  from unwanted extrusion through the gap(s) caused by the system pressure. Conversely, a relatively small gap  53  may be provided between the backup ring  32  and the shaft since this is less material extrusion from the support ring  42 . 
         [0038]    As previously discussed, a contact zone  54  is provided at the ID of the seal ring  36  to provide a seal against the movable surface of the rod  60  of shaft. At the outside diameter (OD) or outside flange  55   b  of the seal ring  36 , a contact zone  56  is provided to form a seal against the inner surface of the gland  58 . The biasing element or spring energizer  38 , such as a canted coil spring, is configured to exert an outwardly directed force to push the outside flange  55   b  into sealing contact with the inner surface of the gland and to push the inside flange  55   a  into sealing contact with the shaft. A gland plate or flange  62  is provided to secure against the gland  58  to retain the sealing system or assembly  30  within the seal space. The gland plate  62  facilitates installation of the seal assembly within the seal box or seal housing  58 . 
         [0039]    As described, the seal assembly  30  is understood to include a first support foot  52  that projects inwardly towards a seal ring  36  and a second support foot  46  that also projects inwardly towards the seal ring to provide axial alignment between different components of the seal assembly. In one example, the first support foot  52  is located on a rigid support ring  34  and the second support foot  46  is located in a rigid backup ring  32 . In the embodiment shown, the second support foot  52  projects axially under the support ring  34  and the first support foot  52  projects axially under the seal ring  36 . In some embodiments, one or more grooves along the OD of the backing ring  32 , support ring  34  or both are incorporated for accommodating a corresponding number of O-rings to further seal the seal assembly against the gland. Engagement detents or other surface features may be incorporated for the various seal assembly components to prevent relative rotation and axial separation during assembly or while in service but less preferred. 
         [0040]    The present seal assembly is further understood to include a seal ring  36  comprising an outer flange  55   a , an inner flange  55   b  comprising a seal lip  54 , and a recessed section  35  on an outer surface. The present seal assembly further includes a support ring  34  comprising an interface feature  40  comprising a concave feature  48  comprising a generally flat section  48   a  and a slant section  48   b  defining a bend therebetween. The slant section forming a support foot  52  and projecting into the recessed section  35  of the seal ring to support the inner flange  55   a  of the seal ring from extrusion due to high operating seal box pressure. In one example, the slant section  48   b  has a thickness at a widest point that is equal to or greater than the thickness of the inside flange to provide support for the inside flange against extrusion. At its narrowest point, the slant section  48   b  has a thickness of about 25% to about 55% of the thickness of the seal lip  54  to provide support for the inside flange  55   a  against extrusion. 
         [0041]    The present seal assembly further includes a backup ring  32  positioned adjacent the support ring  34 . The backup ring  32  comprising an interface feature  42  comprising a concave feature  44  comprising a generally flat section  44   a  and a slant section  44   b  defining a bend therebetween. The slant section  44   b  forming a support foot  46  and projecting into the recessed section  47  of the support ring  34  to support the slant section  48   b  of the support ring  34  from extrusion due to high operating seal box pressure. In one example, slant section  44   b  of the backup ring  32  has a thickness at a widest point that is equal to or greater than the thickness of the inside flange  55   a  of the seal ring to provide support for the slant section  48   b  against extrusion. At its narrowest point, the slant section  44   b  of the backup ring has a thickness of about 25% to about 55% of the thickness of the seal lip  54  to provide support for the slant section  48   a  of the support ring against extrusion. As shown, the length of the slant section  44   b  of the backup ring  32  in the axial direction is about 20% to about 60% of the length of the slant section  48   b  of the support ring  42 . The shorter length slant section  44   b  of the backup ring  32  is incorporated since the structure that it supports, i.e. the support ring  34 , is made from a substantially more rigid material than the seal ring  36 , which means it is less susceptible to extrusion than the seal ring. In one example, the support ring is made from a high modulus high temperature polymer material, such as PEEK (polyetheretherketone), PET (polyethylene terephthalate), PEK (polyetherketone), while the backup ring is made from a metal, such as from steel or stainless steel. In another example, the backup ring  32  and the support ring  34  are both made from a high modulus high temperature polymer material. In yet another example, the backup ring  32  and the support ring  34  are both made from a metal material. 
         [0042]    As further discussed below with reference to  FIG. 5 , high pressure in the sealing box creates tangential forces against every surfaces of the seal ring  36 , which causes the seal ring to expand outwardly in all directions along the two seal flanges  55   a ,  55   b  and axially against the center channel section  27 , in the direction of the atmosphere  10 . These forces cause the seal  36  to extrude outwardly in the direction of the support ring  34  and radially against the slant section  48   b  and support foot  52  of the support ring  34 . If these forces are relatively high, they can cause the support foot  52  to slightly distort and abut against the shaft  60 . However, as the support foot  52  incorporates a recessed section  50   c , friction is reduced when the shaft and the support foot frictionally drag and slide against one another. Pressure acting on the sealing ring  36  not only pushes against the support ring  34  but also against the back up ring  32 . In an alternative embodiment, the support foot  46  on the backup ring  32  may incorporate a multi-point contact surface, similar to the contacts  50   a ,  50   b  on the support ring  34 . The backup ring  32  may also incorporate a groove along its exterior surface with a biasing element, such as a canted coil spring, to also function as a bearing, as further discussed below with reference to  FIG. 2 . 
         [0043]      FIG. 2  is a schematic cross-sectional side view of an alternative seal assembly, which is generally designated  63 . The seal assembly  63  is similar to the seal assembly  30  of  FIG. 1 , such as including a similar seal ring  36  and a similar spring energizer  38 , with a few exceptions. In the present embodiment, the support ring is eliminated in favor of an extended or enlarged rigid backup ring  66 , which is much longer lengthwise than the backup ring  32  of  FIG. 1 . Alternatively viewed, the present embodiment has a single support ring  66  and no backup ring. Thus, while the discussions that follow call out a backup ring, it may alternatively be referred to as a single support ring without a backup ring. 
         [0044]    A spring groove  70  is incorporated on the outside diameter of the backup ring  66  for accommodating a biasing element  64 , such as a radial canted coil spring  64 . In other embodiments, an elastomer may be used, such as an O-ring or a spring embedded O-ring. Alternatively, a ribbon spring or a V-spring may be used instead of a canted coil spring. The biasing element  64 , such as a spring or an elastomer, is configured to center the rigid backup ring  66  with respect to the gland or seal box  58 . Thus, the present rigid backup ring  66  is understood to be dynamically centered relative to the gland  58 , due to the biasing function of the spring or other biasing feature  64 . 
         [0045]    From time-to-time, such as during a surge in the system, due to vibration, due to misalignment, etc., the shaft  60  may move up-and-down in the direction orthogonal to the shaft centerline. When this occurs, the shaft  60  can physically move against the annular interior surface  80  of the backup ring  66  and occupies the gap  82  shown in  FIG. 2 . However, since the backup ring  66  has a biasing element  64 , the backup ring biases or absorbs the shaft&#39;s radial deflection, like a bearing. Thus, the backup ring  66  in the present embodiment not only supports the seal ring from high pressure extrusion, it also functions as a bearing to support the shaft. In another embodiment, the backup ring  66  incorporates one or more multi-point contacts similar to contact points  50   a ,  50   b  in  FIG. 1  along its interior annular surface  80  to reduce friction when in contact with the shaft  60 . In yet another embodiment, two or more grooves with two or more biasing elements may be used instead of a single groove  70  and a single biasing element  64 . 
         [0046]    In one example, the rigid backup ring  66  is made from a high modulus high temperature polymer material, a ferrous, or non-ferrous metal. The high modulus material supports the rear portion of seal ring  36  to reduce material extrusion into radial gaps under high pressure. Although not shown, an optional support foot may be incorporated along the IF feature  72  of the backup ring to support the ID of the seal ring, similar to the embodiment of  FIG. 1 . Still furthermore the support foot may incorporate one or more multi-point contacts to reduce friction when in contact against the moving shaft  60 . 
         [0047]    In one example, the rigid backup ring  66  incorporates a concave geometry  68  near its ID and along the IF feature to receive and support the seal ring and biasing element, which has opposite but corresponding geometry. Because of its high modulus characteristics, the backup ring  66  supports and reduces seal ring  36  material extrusion under high pressure. 
         [0048]    In one embodiment, the IF feature  72  of rigid backup ring  66  is a concave geometry that receives the seal ring and spring energizer for support and reduce seal ring  36  material extrusion under high pressure. Preferably, the IF feature directly contacts the sealing ring  36  without any intervening detents or latches therebetween. This allows the two components  36 ,  66  to float freely without being hung up or caught up by the detents when exerted by system pressure. As shown, the width or thickness  71  of the backup ring  66  that directly contacts the sealing ring  36  measured from an edge of the groove  70  to the contact interface is about 80% to about 200% of the width of the center channel section  27  of the sealing ring  36 . This direct contact with the sealing ring  36  and thickness without any intervening detents or latches are configured to prevent unwanted sealing ring extrusion due to high to very high system pressure. 
         [0049]    Thus, an aspect of the present embodiment is understood to include a seal assembly comprising a dual purpose backup ring, which supports a seal ring from material extrusion and functions as a bearing to support shaft deflection. In a particular embodiment, the backup ring comprises a groove formed along its outside diameter (OD) and has a biasing element located therein. The interface between the backup ring and the seal ring may be generally flat, may be curved, may be concave, and may have a combination of a flat surface and a slant surface. The present embodiment is further understood to include a locking ring (See, e.g.,  FIG. 4 ) a second canted coil spring located in a cavity defined by the seal ring. In yet another embodiment, the contact between the seal ring and the backup ring is without any intervening detent or latch to enable movement without hindrance typically found in devices with detents or latches. To support the seal ring against material extrusion, the surface that directly contacts the center channel section of the seal ring has a thickness of about 80% to 200% or greater than the width of the center channel section. The thickness is measured from the point of contact to an edge of the groove for retaining the biasing element. 
         [0050]    With reference now to  FIG. 3 , a schematic cross-sectional side view of an alternative seal assembly is shown, which is generally designated  73 . The seal assembly  73  is similar to the seal assembly  63  of  FIG. 2 , such as incorporating a similar sealing ring  36  and a backup ring  66 , with a few exceptions. In the present embodiment, the rigid support ring  66  incorporates an inner bearing  74   a  and an outer bearing  74   b  having multi-contact surfaces. The inner and outer bearings  74   a ,  74   b  stabilize the seal assembly against the shaft  60  and provide added reducers to minimize gaps, which act as pathways for unwanted material extrusion. Thus, aspects of the present seal assembly is understood to include a rigid backup ring  66  having a biasing element  64  for centering the seal assembly against the gland and two spaced apart bearing surfaces, for stabilizing and preventing seal material extrusion, and for supporting shaft movement. In other embodiments, there three or more bearings having multi-point contacts are provided. 
         [0051]    In one example, the rigid backup ring  66  is provided with a concave feature  76  for cradling the seal ring  36  to thereby reduce material extrusion. A support foot  78  extends axially of the concave feature  76  to support the seal ring&#39;s ID, to reduce unwanted material contact with the rod  60 . The concave feature  76  includes a generally flat section  76   a  and a slant section  76   b , similar to corresponding features in  FIG. 1  for supporting a recessed section  79  of the sealing ring  36 . 
         [0052]    As shown, the IF feature  72  directly contacts the sealing ring  36  without any intervening detents or latches therebetween to permit free floating between the two components, as previously discussed. The width or thickness  71  of the backup ring  66  that directly contacts the sealing ring  36  measured from an edge of the groove  70  and the contact interface is about 80% to about 150% of the width of the center channel section  27  of the sealing ring  36 . This direct contact with the sealing ring  36  and thickness without any intervening detents or latches are configured to prevent unwanted sealing ring extrusion due to high to very high system pressure. 
         [0053]    With reference now to  FIG. 4 , a schematic cross-sectional side view of an alternative seal assembly is shown, which is generally designated  84 . The seal assembly  84  is similar to the seal assembly  63  of  FIG. 2  and the seal assembly  73  of  FIG. 3 , such as incorporating a similar sealing ring  36  and a backup ring  66 , with a few exceptions. In the present embodiment, the sealing ring  36  has been modified to have a shortened exterior seal flange  88  for accepting a locking ring  86 . The locking ring engages the exterior seal flange  88  and together with the locking ring  86  define a cavity  90  for receiving a canted coil spring  38 . The locking ring  86  further has a tab  92  and a cut-out  94  for forming a cantilevered section to engage against the interior surface of the sealing box. The locking ring  86  further has a ring lip  96  for capturing the canted coil spring  38  within the cavity  90 . 
         [0054]    Like the embodiment of  FIG. 3 , the rigid support ring  66  incorporates an inner bearing  74   a  and an outer bearing  74   b  having multi-contact surfaces. The inner and outer bearings  74   a ,  74   b  stabilize the seal assembly against the shaft  60  and provide added reducers to minimize gaps, which act as pathways for unwanted material extrusion. Thus, aspects of the present seal assembly is understood to include a rigid backup ring  66  having a biasing element  64  for centering the seal assembly against the gland and two spaced apart bearing surfaces, for stabilizing and preventing seal material extrusion, and for supporting shaft movement. In other embodiments, more than three bearing surfaces are incorporated. In still other embodiments, two or more grooves with two or more biasing elements are incorporated instead of just one of each as shown. 
         [0055]    As shown, the IF feature  72  directly contacts the sealing ring  36  without any intervening detents or latches therebetween to permit free floating between the two components, as previously discussed. The width or thickness  71  of the backup ring  66  directly contacts the sealing ring  36  measured from an edge of the groove  70  and the contact interface is about 80% to about 150% of the width of the center channel section  27  of the sealing ring  36 . This direct contact with the sealing ring  36  and thickness without any intervening detents or latches are configured to prevent unwanted sealing ring extrusion due to high to very high system pressure. 
         [0056]    With reference now to  FIG. 5 , a schematic cross-sectional side view of an alternative seal assembly is shown, which is generally designated  100 . The seal assembly  84  comprises a sealing ring  97  comprising an inner seal flange  97   a  and an outer seal flange  97   b  defining a cavity for optionally receiving a canted coil spring (not shown). The sealing ring  97  is shown with an elongated line contact  99  against the shaft  60 . In an alternative embodiment, a recessed or raised section may be incorporated to shorten the line contact, similar to that show in  FIGS. 1-4 . 
         [0057]    The sealing ring  97  is shown spaced from a backup ring  98  for purposes of discussions only. In practice, the sealing ring  97  is abutted against the backup ring  98  and the two corresponding curved surfaces  102 ,  104  mate. The concave feature  104  of the backup ring  98  has two similar terminal ends  104   a ,  104   b  that are shaped into pointed ends for fitting into corresponding shaped ends  120   a ,  120   b  on the sealing ring  97 . The backup ring  98  is also shown spaced from aback wall  106  of the seal housing  58  for discussion purposes only. In practice the outer surface  108  of the backup ring  98  is pushed into mating contact with the back wall  106  on that system pressure from the high pressure region  110  does not cause the various seal components to move during service. 
         [0058]    In the present embodiment, the concave shaped surface  102  of the seal ring and matching curvature  104  on the backup ring allow the two to come together and touch upon application of pressure. During the application of pressure, such as during service, the pressure  112  applied on the seal  97  will be transmitted to the backup ring  98  in all directions, which means that the applied pressure will be applied radially towards the ID and OD of the seal and axially along the back portion of the concave part  104  of the backup ring  98 . 
         [0059]    By applying pressure on the concave portion  104  of the backup ring  98  in a radial manner, it contributes to bringing the backup ring ID and OD in contact with the mating surface of the shaft  60  and housing  58  to eliminate any possible gap that may occur between the ID of the backup ring to form a seal  114  against the shaft  60  and the OD of the backup ring to form a seal  116  against the ID of the housing  58  so as to prevent extrusion of the seal ring  97  under all conditions of pressure. 
         [0060]    The ability to seal against the shaft  60  and the housing  58  with the support ring  98  is highly advantageous in high to very high pressure applications, in particular, in pulsating high pressure applications where extrusion of the seal ring  97  is a high possibility. By providing the backup ring  98  with the concave portion  104 , the design uses system pressure to force the outer  116  and inner  114  diameter of the backup ring  98  into intimate contact with the housing  58  and the shaft  60 , respectively, to prevent or minimize material extrusion of the seal ring through the gaps  118   a ,  118   b  that are normally present with prior art designs. 
         [0061]    By mating the seal ring  97  with the backup ring  98  in the manner described, extrusion of the seal ring under conditions of high pressure is minimized or eliminated thus preventing the deformation of the seal assembly  100  and stabilizing the cross section of the seal ring  97 . This concept is also disclosed and shown with reference to  FIGS. 1 ,  3 , and  4  and optionally incorporated with the assembly of  FIG. 2 . 
         [0062]    As disclosed, the present assemblies, such as the assemblies  30 ,  63 ,  73 ,  84  of  FIGS. 1-4 , are understood to optionally include similar concave surfaces  102 ,  104  as that shown with reference to  FIG. 5 . The mating concave surfaces  102 ,  104  are configured to form sealing contacts  114 ,  116  against adjacent surfaces, such as against the shaft and the seal housing respectively, when under high to very high pressure applications. The seal assembly  100  of  FIG. 5  may also include a locking ring, a canted coil spring inside a seal ring cavity, a groove with a biasing element, and bearing surfaces, similar to other embodiments discussed elsewhere herein. 
         [0063]      FIG. 6  is a process flow diagram depicting an exemplary method of the present disclosure. In one example, the method  130  depicts steps for manufacturing a seal assembly of the present disclosure. In another example, the method  130  depicts steps for using a seal assembly of the present disclosure to seal against a moving shaft. As shown, the method comprises a step  132  for forming a sealing ring comprising an inner flange having a sealing lip and an outer flange having a sealing surface for sealing against a sealing box. The method further includes an optional step of placing a biasing element, such as a canted coil spring in a seal cavity defined by the inner and outer sealing flanges. 
         [0064]    At  134 , the method comprises the step of placing a support ring in adjacent contact with the sealing ring without detents or latches therebetween to permit free floating between the support ring and the sealing ring. 
         [0065]    At  136 , the method comprises the step of placing a backup ring in adjacent contact with the support ring without detents or latches therebetween to permit free floating between the support ring and the backup ring. 
         [0066]    At  138 , the method comprises placing a locking ring in engagement with the sealing and adjusting the biasing element so that it is located in a cavity defined by the combination sealing ring and locking ring. Alternatively, the locking ring may be installed before placing a biasing element in a seal ring cavity. 
         [0067]    In an alternative embodiment, the method comprises the steps for forming the seal assembly of  30  of  FIG. 1 , without a locking ring. 
         [0068]    In another embodiment, the method comprises the steps for forming the seal assembly  63  of  FIG. 2 . 
         [0069]    In another embodiment, the method comprises the steps for forming the seal assembly  73  of  FIG. 3 . 
         [0070]    In another embodiment, the method comprises the steps for forming the seal assembly  84  of  FIG. 4 . 
         [0071]    In another embodiment, the method comprises the steps for forming the seal assembly  100  of  FIG. 5 . 
         [0072]    Although limited embodiments of seal assemblies and their components have been specifically described and illustrated herein, many modifications and variations will be apparent to those skilled in the art. For example, a different combination of pliable seal ring plastic material and rigid plastic housing structure may be used instead of PTFE and PEEK. Furthermore, it is understood and contemplated that features specifically discussed for one seal embodiment may be adopted for inclusion with another seal embodiment, provided the functions are compatible. For example, although a locking ring  86  is only shown with reference to  FIG. 4 , it may be incorporated and used with any of the embodiments of  FIGS. 1-3  and  5 . The present device and system further include methods for forming the seal assemblies as described. Accordingly, it is to be understood that the seal assemblies and their components constructed according to principles of this disclosure may be embodied other than as specifically described herein. The device, system, and method are also defined in the following claims.