Abstract:
A retainer for a gasket used to connect modular piping in a modular gas delivery system to the gas flow controlling components protects the sealing surface of the gasket from scratches before assembly by suspending the gasket at least 0.003 inches inside the retainer, regardless of orientation. Additionally, a slit in the circumference of the retainer allows the retainer to flex open for insertion of the seal gasket, and to compress to a smaller circumference, for a tight fit inside the sealing counterbore. A chamfer on the ID of the retainer aids the easier insertion of the seal into the retainer. In the ID of the retainer, a groove engages a protruding portion of the seal. The depth of this groove is such that with a complete compression of the retainer where the circumferential gap is completely closed, the protruding edge of the seal still has some clearance. This clearance acts as a stop to prevent the retainer from being overly compressed.

Description:
[0001]    This application claims the benefit under 35 U.S.C. 119(e) of the filing date of Provisional U.S. Application Ser. No. 61/420,268, entitled Ring Seal Retainer Assembly and Methods, filed on Dec. 6, 2010, which is commonly assigned herewith and herein expressly incorporated herein by reference, in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]    This invention relates generally to fluid couplings and more particularly to fluid couplings having seal assemblies including flexible gaskets and flexible retainers for those gaskets. 
       BACKGROUND OF THE INVENTION 
       [0003]    Ring seals are typically annularly shaped, defining an axially aligned hole for gas or fluid passage, two axially opposed end surfaces, a radial inner surface and a radially outer surface. A simplistic ring seal has planar end surfaces and smooth circular radial inner and outer surfaces which define the inner diameter (ID) and outer diameter (OD) of the ring seal. However, it is common practice in the industry to utilize seals having different radial cross-sections to obtain varying sealing capabilities for different fluid flow environments. 
         [0004]    A commonly used ring seal is circular and has a radial cross-section of a “C” shape. These “C seals” are constructed with the open side of the C construction facing the center of the ring such as is described in U.S. Pat. No. 5,354,072, or with the open side of the C facing away from the center of two mating surfaces are brought together with the C seal in the middle, the C seal is compressed with the open side of the C cross-section closing during compression. The ductile properties of the seal permit plastic deformation to occur without damaging the mating surfaces. 
         [0005]    Additional seals which have been available include “V” seals which are also circular, but instead of having a “C” cross-section, have a “V” cross-section with the low point of the V constructed to point either inwardly or outwardly towards the center of the seal. Other seals known in the art include “Z” seals and simple  0 -rings. These other types of seals are discussed, for example, in U.S. Pat. No. 6,708,985. Both of the &#39;072 and &#39;985 patents are herein expressly incorporated by reference, in their entirety. 
         [0006]    Still another type of ring seal known in the industry is the “W”-seal type face seal, particularly adapted for use in surface mount gas panels. Such a sealing system is disclosed, for example, in U.S. Pat. No. 7,140,647, also herein expressly incorporated by reference, in its entirety. The “W” seal in the &#39;647 patent uses a snap ring situated on the inside of a retaining ring, identified in the patent as a guide, to retain the W-seal in the retainer and to keep the sealing surfaces on the W-seal or gasket protected from scratches. The &#39;647 patent retainer or guide also has a snap ring situated on its outside diameter to keep the retainer engaged in the counterbore. 
         [0007]      FIGS. 1-4  illustrate a typical prior art “W” seal  2 , comprising a retainer sleeve  2   a,  and a metal seal  2   b.  As discussed above, the assembly  2  further comprises an interior snap ring  2   c  and an exterior snap ring  2   d.  To accommodate these snap rings, there is provided a first Outside Diameter (OD) groove  2   e  on the outer surface of the retainer sleeve  2   a,  and an Inside Diameter (ID) groove  2   f  on the inner surface of the retainer sleeve  2   a.  Additionally, a second OD groove  2   g  is provided on the outer surface of the metal seal  2   b,  which corresponds to the ID groove  2   f,  wherein the second OD groove  2   g  and the ID groove  2   f  together accommodate the interior snap ring  2   c.  It should be noted that the cut in the ring and seal shown in  FIG. 2  is illustrative only, for the purpose of illustrating particular constructional features of the seal assembly. In actuality, both the seal and the retaining ring are circumferentially continuous and unbroken. 
         [0008]    Thus, each prior art W-seal requires four separate parts, including two snap rings, and three formed grooves for accommodating those snap rings, resulting in manufacturing complexity and relatively high cost. Additionally, these snap rings have often been found to make it substantially more difficult to remove the seal from the counterbore when desired, causing productivity problems, and sometimes damage to the seal assembly. Another reason why these types of seals often stick in the counterbore when it is desired to remove them is because the seal is a thick VCR gasket, and tends to compress when expanded, thus causing the retainer to also expand. 
         [0009]    There are other problems with prior art ring seals of this type. These problems include the seal sometimes pushing the bead over, causing a leak due to high load, as well as the seal tending to move off-center. The off-center problem is often related to a build-up of tolerances because of the multiple parts, including the two snap rings, as well as over-compression of the snap ring, which causes the round retainer to distort into an oval or ellipse, thus forcing the seal off-center. 
         [0010]    What is needed, for above described sealing system applications, is a face seal system which affords certain functional advantages without the necessity and expense involved in employing snap rings, and which is preferably constructed to permit easy removal from the counterbore. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention addresses the issues noted above, by providing a ring sealing system suitable for applications such as a semiconductor manufacturing modular gas delivery system. 
         [0012]    Specifically, the inventive sealing system comprises a retainer for a gasket used to connect modular piping in a modular gas delivery system to the gas flow controlling components. The retainer design protects the polished sealing surface of the W-seal gasket from scratches before assembly by suspending the gasket at least 0.003 inches inside the retainer, regardless of orientation. Additionally, a slit or gap in the circumference of the retainer allows the retainer to flex open for insertion of the W-seal gasket. A small chamfer on the ID of the retainer, in certain embodiments, aids the easier insertion of the W-seal into the retainer. 
         [0013]    The gap in the circumference of the retainer also allows the retainer to compress to a smaller circumference, for a tight fit inside the sealing counterbore. In the ID of the retainer, there is a groove machined for a protruding portion of the W-seal to engage. The depth of this groove is such that with a complete compression of the retainer where the circumferential gap is completely closed, the protruding edge of the W-seal still has some clearance. This clearance, which acts as a stop to prevent the retainer from being overly compressed, insures that the seal and retainer assembly will not jam while trying to insert the assembly into the counterbore. 
         [0014]    The slit or gap in the circumference of the retainer allows for a larger tolerance in the machining on the OD of the retainer. With current designs, a slightly oversized OD will prevent insertion of the retainer and seal assembly into the counterbore because there is no room for compression. In the inventive design, the retainer is free to close up to 0.010 inches as currently manufactured. The gap in the circumference can be made larger and achieve the same results. 
         [0015]    There is a slight chamfer around the OD of the retainer for easier location of the retainer on the counterbore. The top half of the retainer has a slightly smaller OD for easy alignment of surface mount components. This is especially important for components with multiple sealing points that engage on the same block. 
         [0016]    An additional advantageous feature of the present invention is the employment of a chamfer on at least one outside corner of the annular retaining member for easing installation of the retaining member into a counterbore. A chamfer may also be disposed on at least one inside corner of the annular retaining member for easing insertion of the sealing member into the retaining member. Yet another advantageous feature of the invention is the inclusion of a load adjustment groove disposed on the ID of the seal member, for substantially improving the elastic response of the seal. 
         [0017]    More particularly, there is provided a ring seal assembly which comprises an annular metal seal having an ID, an OD, an upper sealing surface, and a lower sealing surface, wherein the OD comprises a larger OD portion and a smaller OD portion. An annular metal retaining ring is also provided, comprising an outer wall having an ID and OD, wherein the ID of the retaining ring is sufficiently large to accommodate the OD of the annular metal seal within its boundaries. Advantageously, the ID of the retaining ring has a groove disposed therein which is circumferentially arranged to receive the larger OD portion of the annular metal seal. The larger OD portion of the seal comprises metal, and extends radially into the groove and the remaining ID portion of the retaining ring bounding the smaller OD portion of the seal. 
         [0018]    The retaining ring is circumferentially compressible to a reduced circumferential size. The compressibility arises because a gap exists between at least a portion of the circumference of the retaining ring and a corresponding portion of the circumference of the seal when the retaining ring is in a relaxed state and thus at its full natural circumferential size. This gap permits the retaining ring to be compressed without impacting the seal. 
         [0019]    A split is disposed through at least a portion of the retaining ring at a particular circumferential location thereon to provide the retaining ring with its circumferential compressibility. In one illustrated embodiment, this split extends upwardly from a bottom edge of the retaining ring through only the larger OD portion of the retaining ring. Preferably, a plurality of these partial splits are circumferentially spaced about said retaining ring. In other embodiments a single split extends upwardly through the entire height of the circumferential wall defining the retaining ring. 
         [0020]    The section of the retaining ring outer wall defining the larger ID portion is relatively thick and the section of the retaining ring outer wall defining the smaller ID portion is relatively thin. In certain inventive embodiments, the OD of the retaining ring is substantially uniform, while in others, the OD of the retaining ring comprises a smaller OD portion and a larger OD portion. In still another illustrated embodiment, a removal groove is disposed in the smaller retaining ring OD portion. This removal groove assists in visually determining the proper orientation of the seal assembly in the counterbore, and preferably groove forms a radially-oriented ledge for assisting in removal of the assembly from a counterbore. 
         [0021]    The OD of the seal preferably comprises a load adjusting feature. This load adjusting feature may comprise a groove extending circumferentially about the OD of the seal, or it may comprise a plurality of circumferentially spaced bores. The circumferentially spaced bores may form a single row between the smaller OD portion and the larger OD portion of the seal, or may form a row on the smaller OD portion of the seal and a second row on the larger OD portion of the seal. 
         [0022]    An important feature of the present invention is the provision of a chamfer on at least one inside corner of the retaining ring for easing insertion of the sealing member into the retaining member. A second chamfer may be disposed on at least one outside corner of the retaining ring, and even more advantageously, a chamfer or angled step may be provided on the larger OD portion of the seal for engaging the chamfer on the retaining ring. 
         [0023]    The inventive seal assembly does not have any snap rings, an important advantage over prior art approaches. 
         [0024]    In another aspect of the invention, there is provided a ring seal assembly, which comprises an annular seal member having an inner diameter (ID) and an outer diameter (OD), and having an axial hole defined by the ID for fluid passage, wherein the OD of the seal member comprises a smaller OD portion and a larger OD portion. An annular retaining member is also provided, having an ID and an OD, wherein the ID of the retaining member is larger than the OD of the seal member. A chamfer is provided on at least one inside corner of the annular retaining member for easing insertion of the sealing member into the retaining member. The OD of the seal member comprises a smaller OD portion and a larger OD portion and the ID of the retaining member comprises an axially cylindrical first portion and a second portion comprising a groove extending radially outwardly of the first portion for receiving and accommodating the larger OD portion of the seal, which extends radially outwardly into the groove. 
         [0025]    In its assembled state, with the seal disposed within the ID of the retaining ring, there is a gap between the seal and the retaining ring about a portion of the circumference of the assembly, to thereby permit compression of the retaining ring without substantial contact of the retaining ring with the seal. In one embodiment, the OD of the retaining ring comprises a smaller OD portion and a larger OD portion. A recess is disposed between an annular edge of the retaining ring and one of the upper and lower sealing surfaces of the sealing ring when the seal assembly is in an assembled state, the recess functioning to protect the one of the upper and lower sealing surfaces from inadvertent contact damage. A second recess is disposed between an opposing annular edge of the retaining ring and the other of the upper and lower sealing surfaces of the sealing ring when the seal assembly is in the assembled state, to thereby protect the other of the upper and lower sealing surfaces from inadvertent contact damage. 
         [0026]    Advantageously, the inventive assembly does not have any snap rings. 
         [0027]    In still another aspect of the invention, there is provided a fluid coupling which comprises a base block, a component, wherein the component is assembled to the base block, and a fluid flow passage extending through the assembled base block and component. A counterbore is disposed in the fluid passage and extends radially outwardly into the assembled base block and component, wherein each of the base block and component have a sealing bead extending into the counterbore for engaging a seal. A ring seal assembly is disposed in the fluid flow passage, and comprises an annular metal seal having an ID, an OD, an upper sealing surface, and a lower sealing surface. The OD comprises a larger OD portion and a smaller OD portion. An annular metal retaining ring comprises an outer wall having an ID and OD, wherein the ID of the retaining ring is sufficiently large to accommodate the OD of the annular metal seal within its boundaries. The ID of the retaining ring has a groove disposed therein which is circumferentially arranged to receive the larger OD portion of the annular metal seal. The larger OD portion of the seal comprises metal and extends radially into the groove and the remaining ID portion of the retaining ring bounding the smaller OD portion of the seal. The ring seal assembly is secured into the counterbore such that the sealing beads engage the annular metal seal to seal the joint between the base block and the component. 
         [0028]    In yet another aspect of the invention, there is disclosed a method of assembling a resilient retaining ring and an annular seal, wherein the retaining ring comprises a chamfered edge. The method comprises a step of engaging the seal against the chamfered edge to expand the retaining ring, and a further step of sliding the seal into engagement with a groove on an ID surface of the retaining ring. Another step is that of permitting the retaining ring to expand circumferentially to seat and center the seal. 
         [0029]    The invention, together with additional features and advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying illustrative drawings. In these accompanying drawings, like reference numerals designate like parts throughout the figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]      FIG. 1  is an isometric view of a prior art W-seal; 
           [0031]      FIG. 2  is an isometric view of the W-seal shown in  FIG. 1 , wherein a circumferential portion has been removed to illustrate a cross-section of the seal; 
           [0032]      FIG. 3  is a cross-sectional view of the prior art W-seal shown in  FIGS. 1 and 2 ; 
           [0033]      FIG. 4  is an exploded view of the prior art W-seal shown in  FIGS. 1-3 ; 
           [0034]      FIG. 5  is a top view of one embodiment of a retaining ring constructed in accordance with the principles of the present invention; 
           [0035]      FIG. 6  is a cross-sectional view of the retaining ring shown in  FIG. 5 ; 
           [0036]      FIG. 7  is a detailed cross-sectional view of the portion of  FIG. 6  denoted by the letter A; 
           [0037]      FIG. 8  is an isometric view of the retaining ring of  FIGS. 5-7 ; 
           [0038]      FIG. 9  is a top view of a modified embodiment of the retaining ring of the present invention; 
           [0039]      FIG. 10  is a cross-sectional view of the retaining ring shown in  FIG. 9 ; 
           [0040]      FIG. 11  is a detailed cross-sectional view of the portion of  FIG. 10  denoted by the letter B; 
           [0041]      FIG. 12  is an isometric view of the retaining ring of  FIGS. 9-11 ; 
           [0042]      FIG. 13  is a top view of an embodiment of a sealing gasket constructed in accordance with the principles of the present invention; 
           [0043]      FIG. 14  is an elevation of the gasket shown in  FIG. 13 ; 
           [0044]      FIG. 15  is a cross-sectional view of the gasket shown in  FIGS. 13 and 14 ; 
           [0045]      FIG. 16  is a detailed cross-sectional view of the portion of  FIG. 15  denoted by the letter C; 
           [0046]      FIG. 17  is an isometric view of the gasket shown in  FIGS. 13-16 ; 
           [0047]      FIG. 18  is a top view of a modified embodiment of a sealing gasket according to the present invention; 
           [0048]      FIG. 19  is an isometric view of the gasket shown in  FIG. 18 ; 
           [0049]      FIG. 20  is an elevation of the gasket shown in  FIGS. 18 and 19 ; 
           [0050]      FIG. 21  is a cross-sectional view of the gasket illustrated in  FIGS. 18-20 ; 
           [0051]      FIG. 22  is an isometric view of a modified embodiment of a retaining ring forming a part of the seal ring assembly of the present invention; 
           [0052]      FIG. 23  is an isometric view of a seal ring assembly of the present invention, shown using the retaining ring illustrated in  FIG. 12 , for exemplary purposes; 
           [0053]      FIG. 24  is an elevation of another modified embodiment of a sealing gasket according to the present invention; 
           [0054]      FIG. 25  is an elevation of yet another modified embodiment of a sealing gasket according to the present invention; 
           [0055]      FIG. 25   a  is an elevation of still another modified embodiment of a sealing gasket according to the present invention; 
           [0056]      FIG. 26  is a cross-sectional view illustrating the retaining ring and gasket assembly shown in  FIG. 23 , for exemplary purposes; 
           [0057]      FIG. 27  is a cross-sectional view similar to  FIG. 26  illustrating an assembled seal, according to the invention, after it has been fully installed and compressed to its operational status; 
           [0058]      FIG. 28  is a top view of a fluid flow system in which the inventive seal assembly of the present invention has been installed; 
           [0059]      FIG. 29  is a cross-sectional view taken through lines  29 - 29  of  FIG. 28 ; 
           [0060]      FIG. 30  is a cross-sectional view taken through lines  30 - 30  of  FIG. 29 ; 
           [0061]      FIG. 31  is an exploded isometric view of the fluid sealing system shown in  FIGS. 28-30 ; 
           [0062]      FIG. 32  is an enlarged exploded isometric view of the portion of the system illustrated in  FIG. 31  which is denoted by the letter E; 
           [0063]      FIG. 33  is an exploded isometric view similar to  FIG. 31 , showing the seal in an assembled state; and 
           [0064]      FIG. 34  is an enlarged exploded isometric view of the portion of the system illustrated in  FIG. 33  which is denoted by the letter F. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0065]    Referring now more particularly to  FIGS. 5-34 , wherein like reference numerals designate identical or corresponding parts throughout the several views and embodiments, and the terms “lower” and “upper” are with respect to the figures only, and not necessarily with the orientation of the sealing assembly in an actual installation, there is shown in  FIGS. 23 and 26  a ring seal assembly  10 , constructed and assembled in accordance with the principles of the present invention. The assembly  10  comprises a retainer or retaining ring  12  surrounding, in circumferential fashion, an annular step seal or gasket  14 . The gasket  14  comprises a center hole  16 , and an annular body element  18 . The retainer  12  is also annular in construction, comprising an annular body element  20  and a cylindrical inner wall  22  defining a center hole, into which the gasket  14  is inserted. Each of the retaining ring  12  and the gasket  14  are preferably fabricated of sheet steel or other suitable metal, having elastic characteristics and capable of being machined. In the embodiment shown in  FIG. 26 , the outer diameter (OD) of the retaining ring  12  is stepped, having a smaller OD portion  24  and a larger OD portion  26 . A “removal groove”  27  is disposed on the smaller OD portion  24  of the retaining ring  12 , for assisting in ensuring that the seal assembly is properly installed. The seal assembly  10  is so small that it is hard to see which side is larger (greater OD) without magnification, sometimes causing the installer to place the retainer in the counterbore in the wrong orientation. Essentially, this removal groove feature provides a visual identifiable feature, to assist the installer in ensuring the proper orientation of the seal assembly in the counterbore. Additionally, the groove serves as a place to hook a seal removal tool onto the retainer. Current design approaches require the person removing the seal assembly to exert radial pressure on the retainer wall, pulling the ring in an attempt to lift the assembly. If an insufficient amount of radial pressure is exerted, the assembly slips out of the removal tool. However, with the use of the groove  27  to receive and retain the removal tool, the operator can exert radial pressure as well as have a hook under the small ledge  27   a  created on the OD  24 . This engagement with the ledge functions to prevent the seal assembly from slipping out of the removal tool. 
         [0066]    A retainer ID groove  28  is disposed on the ring  12 , within the larger OD portion  26 . An outer chamfer  30  is disposed on each corner on the OD of the retainer  12 . Inner chamfers  32  are disposed on the lower corners of the ID of the retainer  12 , as well. 
         [0067]    The gasket  14  comprises a substantially cylindrical ID  34 , surrounding and defining the center hole  16 . The OD of the gasket  14  comprises a smaller OD portion  36  and a larger OD portion  38 . Between these two portions  36 ,  38  is disposed a load adjustment groove  40 , or, in alternative embodiments, cylindrical bores or depressions  40 . 
         [0068]      FIG. 27  illustrates the ring seal assembly  10  in an installed configuration. The seal assembly shown in  FIG. 27  is somewhat modified, in that in the  FIG. 27  embodiment the OD of the retaining ring  12  comprises the smaller OD portion  24  and the larger OD portion  26 , but the smaller OD portion  24  does not include the removal groove  27  shown in  FIG. 26 . Either embodiment is within the scope of the present invention, the removal groove  27  being a desirable, but not always required, feature, depending upon application and other design considerations. 
         [0069]    As illustrated in  FIG. 27 , the seal assembly  10  is disposed within a gas or fluid flow path  42 , wherein the fluid flow moves in the direction of the arrow  44 . Defining the fluid flow path  42  are a component  46  and a base block  48 . A component counterbore  50  is machined into the component  46 , while a complementary base block counterbore  52  is machined into the base block  48 . It is noted that the outer chamfers  30  are advantageously designed to permit easy insertion of the retaining ring  12  into the counterbores  50 ,  52 . The lower ends of the inner chamfers  32  extend into the ID of the ring  14  farther than the cylindrical inner wall portion  22 , so that the retainer can be spread, using an angle tool, from the inside to facilitate ready insertion of the seal  14  into the center hole  22  of the retainer  12 . 
         [0070]    Upon installation of the seal assembly  10  into the flow path  42 , the component  46  and base block  48  are compressed axially about the seal assembly  10 , causing a sealing bead  54  on each of the blocks  46 ,  48  to engage the gasket  14 . It is noted that, even when fully compressed, the retainer  12  remains spaced from the walls defining the counterbore  50 ,  52 , as shown in  FIG. 27 , allowing continued play between the retainer and the counterbore. 
         [0071]    It is important to note that the retainer  12  extends axially substantially above and below the seal  14 . The reason for this is to ensure that, even when compressed, the upper and lower surfaces of the seal  14 , which are highly polished, are protected from damage such as scratching, in order to preserve optimal seal integrity. 
         [0072]    With reference now to  FIGS. 5-21 , various embodiments of each of the retainer  12  and gasket  14  are illustrated. It should be noted that any of the retainer embodiments and gasket embodiments may be employed, as shown in  FIGS. 26 and 27 , within the scope of the present invention, with a caveat that specific complementary features and dimensions of each element must be coordinated to fit together appropriately. The specific dimensions shown in the figures are exemplary only. 
         [0073]    With respect to  FIGS. 5-8 , one embodiment of a retaining ring  12  is shown. As shown, a significant feature of the retaining ring  12  is the inclusion of a slot or gap  56  for the purpose of assisting fixation of the retainer  12  and gasket  14  within the counterbore. In this embodiment, the radial slot  56  passes completely through the wall of the retainer  12  for its entire axial length, thereby making it feasible to temporarily spread the slot (gap)  56  elastically. This spreading of the gap  56  enlarges the effective diameter of the center hole  22  sufficiently to accept the larger outside diameter portion  38  of the gasket  14 , and to easily position the retainer inside diameter groove  28  over the larger outside diameter portion  38  of the gasket  14 . This arrangement thus allows the gasket  14  to effectively float within the confines of the retainer  12 . 
         [0074]    As also shown throughout the various embodiments, chamfers  30  and  32  are preferably approximately  45  degrees, though that angle can be varied to a certain extent without substantially affecting ease of assembly. 
         [0075]    A somewhat modified embodiment of the retaining ring  12  is illustrated in  FIGS. 9-12 . The primary difference between this embodiment and that of  FIGS. 5-8  is the utilization of a retaining ring having a stepped OD, comprised of the aforementioned smaller OD portion  24  and larger OD portion  26 . This embodiment is the one shown, for illustration purposes, in  FIG. 27 . 
         [0076]      FIGS. 13-17  illustrate one embodiment of the step seal or gasket  14  in accordance with the present invention. As shown, this embodiment comprises a smaller OD portion  36  and a larger OD portion  38 , with a plurality of bores  40  spaced and disposed in each of the smaller OD portion  36  and the larger OD portion  38 . These bores circumferentially alternate, as shown in  FIG. 17 , so that only one is shown in  FIGS. 15 and 16 . 
         [0077]      FIGS. 18-21  illustrate a somewhat modified embodiment of the step seal or gasket  14 . The primary difference, other than with respect to certain dimensions, between the two embodiments is that in the  FIG. 14  embodiment a single circumferential load displacement groove  40  is employed, instead of the bores  40  of  FIGS. 9-13 . 
         [0078]      FIG. 22  illustrates yet another modified embodiment of the retaining ring  12 . This embodiment is similar to the embodiment of  FIG. 12 , also shown in FIG.  27 , differing only in the employment of a series of circumferentially spaced partial slots  58 , rather than the full slot  56  shown in  FIG. 12 . As shown, these slots  58  only extend upwardly from the lower edge of the retainer  12  through the thicker circumferential section of the retainer wall, i.e. the OD  26 . The partial slots  58  allow for the bottom half of the retainer  12  to spread open for receiving and protecting the seal  12 . During the insertion of the seal, the bottom half of the retainer deforms to a slightly larger OD. Upon insertion into a counterbore, this enlarged OD will be forced inwardly and provide spring tension to hold the assembly in place. 
         [0079]      FIG. 24  illustrates yet another modified embodiment of the step seal or gasket  14 . This embodiment is similar to that shown in  FIGS. 13-17 , but comprises only a single row of spaced bores  40 , between the smaller ID portion  36  and the larger ID portion  38 , rather than the dual rows of bores  40  shown in  FIGS. 14 and 17 . 
         [0080]      FIG. 25  shows still another modified embodiment of the gasket  14 , similar to that shown in  FIG. 24 , except for the addition of chamfer or angled step  59  about an upper circumferential edge of the larger ID portion  38 . This angled step  59 , preferably having an angle of about 45°, though this angle may be varied in accordance with design considerations, is intended to mate with the chamfer  32  on the retainer  14 , upon assembly of the seal ring or gasket  14  within the retainer ring  12 , to reduce the load on the assembly upon insertion. 
         [0081]    Yet another modified embodiment of the gasket  14  is illustrated in  FIG. 25   a , wherein the OD of the seal is solid, having neither a groove or a series of bores for load adjustment. In certain embodiments, where such functionality is not required, this embodiment may be fabricated at substantially lower cost. This solid walled embodiment may employ the angled steps or chamfers  59 , as shown in the  FIG. 25  embodiment, if desired. 
         [0082]    Referring once again to  FIG. 27 , it is noted that there is play between the seal and the retainer, even when assembled. The reason for this is to ensure that when the retainer compresses, it does not hit the seal, because otherwise it would not be able to be compressed to a dimension smaller than the counterbore, which would affect seal integrity. The split or slot  56 , 58  is a key to this feature, as it serves as the stop to control the amount of compression of the retaining ring  12 . Upon compression, the ring  12  compresses until the two surfaces defining the split engage one another. Another notable feature is that the larger OD portion  38  of the stepped seal is captured top and bottom by the retainer  14  in its relaxed or pre-compression position. There is no interference between the retainer and the elastic response modifying portions (bores or load adjustment groove  40 ) of the seal. 
         [0083]    As noted above, an important feature of the present invention is that both upper and lower sealing surfaces  60  ( FIG. 26 ) of the seal  14  are recessed relative to the upper and lower edges of the retainer ring  12 . In other words, there is a recess between respective opposed sealing surfaces  60  of the seal  14  and the upper and lower edges of the retainer ring  12 . The purpose for this recess is to fully protect the polished sealing surfaces  60  of the seal ring  14  during handling. 
         [0084]      FIGS. 28-34  illustrate the seal assembly  10  in a typical sealing environment, wherein the fluid flow path  42  to be sealed is defined by the component  46  and base block  48  which are attached by bolts  62  or other suitable means. The seal  10  is adapted to be fitted within the space formed by the component counterbore  50  and corresponding base block counterbore  52 , and to form a leak-tight fluid connection therein, via sealing beads  54 . As is the case with  FIGS. 26 and 27 , any of the seal embodiments disclosed herein may be employed in the combination illustrated in  FIGS. 29-34 . 
         [0085]      FIGS. 31-34  illustrate the process of snapping the metal seal assembly into the seal port counterbore  52  to install the seal. In  FIGS. 31-32 , the seal  10  is positioned above the counterbore  52 . The next sequential step is illustrated in  FIGS. 33-34 , wherein the seal  10  is dropped into the counterbore  152 . The two spring arms formed by the split  56 , and comprising the retainer ring  12 , fully wrap around the metal seal  14  and function to locate the metal seal at the center of the fluid path  42 . The seal  14  retains itself in a centered orientation within the counterbore because of the tension of the spring-loaded retaining ring  12 . 
         [0086]    To remove the retainer assembly from the counterbore, a slight pressure is applied against one side of the exposed top half of the retainer, thereby closing the slit gap  56 , and then applying a slight upward pressure to flip the assembly out of the counterbore. No tools are required. 
         [0087]    Advantages of the present invention include the following. The innovative retainer design functions to force the seal to a centered orientation. The retainer ring is chamfered at both ends to allow for easy insertion. This allows the columnar retainer to easily bottom out in the connecting block into which it is inserted prior to closure. The larger diameter portion of the stepped seal is captured top and bottom by the retainer in its relaxed or pre-compression position. There is no interference between the retainer and the elastic modifying portions (groove or bores) of the seal. The stepped seal has bores or a groove disposed thereon for adjusting the elastic response of the seal, and the retainer is internally and externally contoured to the steps for uniform clearance and flexural response to closing forces. 
         [0088]    While this invention has been described with respect to various specific examples and embodiments, it is to be understood that various modifications may be made without departing from the scope thereof. Therefore, the above description should not be construed as limiting the invention, but merely as an exemplification of preferred embodiments thereof and that the invention can be variously practiced within the scope of the following claims.