Abstract:
An improved seal retainer for an undersea hydraulic coupling member, which utilizes metal seals to maintain fluid integrity, is disclosed. The metal seals of the present invention are designed to either create an absolute barrier to fluid flow, or utilize a press or interference fit to create a barrier to fluid flow to ensure fluid integrity between the undersea hydraulic coupling and the environment outside the hydraulic coupling.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates, in general, to hydraulic couplings, and specifically to hydraulic couplings used in undersea drilling and production applications. More particularly, the invention involves undersea hydraulic couplings having seal retainers that hold and retain seals between the coupling members. The improved seal retainer of the present invention utilizes press fit or interference fit metal seals to provide the fluid integrity between the hydraulic coupling and surrounding fluid environment. 
   2. Description of Related Art 
   Subsea hydraulic couplings are old in the art. The couplings generally consist of a male member and a female member with seals to seal the junction between the male and female members. The female member generally has a cylindrical body with a relatively large diameter bore at one end and a relatively small diameter bore at the other. The small bore facilitates connections to hydraulic lines, while the large bore contains the seals and receives the male portion of the coupling. The male member includes a probe section insertable into the large bore of the female member. According to various embodiments of the device, the seals either abut the end, or face, of the male member or engage the male member about its outer circumference. Hydraulic fluid is then free to flow through the female and male portions of the coupling and seals prevent that flow from escaping about the joints of the coupling. 
   Optionally, a check valve may be installed in the female member and also in the male member. Each check valve is open when the coupling is made up; however, each check valve closes when the coupling is broken so as to prevent fluid from leaking out of the system of which the coupling is part. 
   U.S. Patent Application Publication No. 2004/0084902 a1 corresponding to application Ser. No. 10/285,062 filed on Oct. 31, 2002 commonly assigned to the assignee of the present invention, entitled “Seal Retainer For Undersea Hydraulic Coupling,” incorporated herein by reference, discloses a seal retainer for use with a female coupling member, wherein the seal retainer contains all seals for the female coupling. The seal retainer may be easily removed and repaired without damage to the female coupling member. 
   In higher pressure situations additional seal integrity may be desired to prevent fluid leakage from the hydraulic coupling. Therefore, what is needed is a seal retainer that contains metal seal that can be hydraulic pressure actuated to prevent fluid leakage in either direction inside the coupling. A copending application filed on the same day as the present application with the same assignee and inventor entitled “Seal Retainer with Pressure Energized Metal Seal Members for Undersea Hydraulic Couplings” is directed to the use of pressure energized metal seals and is incorporated herein by reference. 
   SUMMARY OF THE INVENTION 
   The present invention provides an improved seal retainer for an undersea hydraulic coupling that provides higher integrity press fit or interference fit metal seals while still providing the benefits of removal of seals as a single unit together with the seal retainer. The metal seals are designed to engage with a shoulder inside the receptacle of the female coupling member to prevent fluid passing through the coupling from mixing with fluid in the environment outside the hydraulic coupling. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein. 
       FIG. 1  is a section view of the improved seal retainer of the present invention according to a first embodiment. 
       FIG. 2  is a section view of a female coupling member with the improved seal retainer according to the first embodiment. 
       FIG. 3  is a section view of the improved seal retainer of the present invention according to a second embodiment. 
       FIG. 4  is a section view of a female coupling member with the improved seal retainer according to a second embodiment. 
   

   DETAILED DESCRIPTION 
   As shown in  FIG. 1 , in a first embodiment, seal retainer  10  comprises shell  21  and seal carrier  30 , with central bore  20  extending therethrough. The seal carrier fits together with the shell to form the seal retainer that may be inserted and removed from a female undersea hydraulic coupling member. The seal retainer  10  holds and secures one or more annular seals that are configured to engage the male coupling member. The seal retainer  10  also comprises seal members configured to engage the female coupling member. 
   In a first embodiment, the shell  21  is a generally ring-shaped body with an outer diameter  22  that may be threaded to engage the female coupling member. The shell  21  has first end  28 , second end  45 , first larger inner diameter  23 , second smaller inner diameter  25 , and internal shoulder  27  between the first and second inner diameters. The shell also may include negative or reverse angle shoulder  26  that extends radially inwardly from internal shoulder  27 . Holes  35  may be included in the first end of the shell, and a spanner or other tool may be inserted into the holes to rotate the shell to engage or disengage it from the female member. 
   In the first embodiment, the seal carrier  30  is a generally ring shaped body, part of which engages or fits at least partially into the shell. The seal carrier  30  has a first end  39 , which fits into the shell, second end  29 , first larger outer diameter  42 , second smaller outer diameter  32 , first larger inner diameter  36 , and second smaller inner diameter  34 . In one embodiment, the seal carrier  30  may have negative or reverse angle shoulder  37  between the first larger inner diameter and second smaller inner diameter. The seal carrier also may include outer shoulder  31  between the first larger outer diameter and the second smaller outer diameter. 
   In one embodiment, the first end of the seal carrier slides into the first larger inner diameter  23  of the shell. There may be little or no clearance between the second smaller outer diameter of the seal carrier and the inner diameter of the shell, or there may be a slight interference fit. When the first end of the seal carrier is fully inserted into the shell, the first end  39  may abut internal step  27  of the shell, and first end  45  of the shell may abut outer shoulder  31  of the seal carrier. 
   In the embodiment of  FIG. 1 , the seal retainer holds third annular seal  60  between reverse angled shoulders  26  and  37  that restrain the seal from implosion into central bore  20 . Third annular seal  60  may be an elastomeric ring with a dovetail cross section, and may have a dovetail interfit between the reverse angled shoulders. The inner diameter of the third annular seal  60  may extend further into the central bore than the smaller inner diameters of the shell or seal carrier, to seal radially with the male member when the male member is in the receiving chamber. O-rings  62  are included on the outer circumference of the third annular seal to form a seal with inner diameter  36  of the seal carrier  30 . 
   Seal carrier  30  is preferably made of metal. Machined out of the body of seal carrier  30  is a groove that extends radially around the face of end  29 . At the edges of the groove, sharp blade-like extensions are formed to create metal blade seals  70 . An elastomeric o-ring  72  is placed in the groove to act as a secondary seal to the metal blade seals. 
     FIG. 2  shows the seal retainer of  FIG. 1  as it is installed in a female coupling member  74 . End  29  of the seal carrier seats against shoulder  76  of the female coupling member. As the shell  21  is tightened down, the metal blade seals  70  will pierce the metal surface of the shoulder  76  forming an absolute barrier to fluid flow in either direction. Each metal blade seal backs up the other with the o-ring  72  acting as an additional secondary seal. An additional seal member in the form of metal “c” seal  78  is used to form seals with the probe of the male coupling member as well as the shoulder  76  of the female coupling member. 
     FIG. 3  shows a second embodiment of the present invention. The elements of the seal retainer of  FIGS. 1 and 2  that are the same in  FIG. 3  have the same number. What is different is that instead of using the metal blade seals, an extension, that has tapered edges and a groove cut therein, is added to end  29  of the seal carrier. The tapered edges form two metal angular seals  80  that extend radially around the face of end  29 . 
     FIG. 4  shows the second embodiment of the seal retainer shown in  FIG. 3  as it is installed in a female coupling member. The female coupling member  82  is modified from the one shown in  FIG. 2  by having the angled groove  84  cut into shoulder  76 . The angles of groove  84  are machined so as to match up with the metal angular seals  80  of the seal retainer. The angles of groove  84  can be cut either so there is a snug interference fit with the metal angular seals, or they can be cut so that as the seal retainer is tightened down, the metal angular seals  80  are slightly displaced inward to create a press fit. Preferably the inward displacement is about 0.001 inches. Once installed, the interference or press fit between the angled sides of groove  84  and the metal angular seals  80  form two radial seals between the seal retainer and the female coupling member. The o-ring  72  provides a back up or secondary seal between the seal retainer and the female coupling member. 
   As those of skill in the art, not only are there variations to the configurations of the metal seals that may be made, but the invention could be used with additional metal seals. The invention, accordingly, should be understood to be limited only by the scope of the appended claims.