Abstract:
The present invention provides an end cap sealing system for sealing an open piping end. The end cap sealing system includes an end cap having an end cap core. The end cap core has a generally cylindrical end with a circumferential groove formed around the exterior thereof and a closed end that defines a generally circular rim. An o-ring is positioned within the groove for sealingly engaging an interior wall of the piping open end. The end cap sealing system also includes a generally circular clamp having a channel formed therein for capturing the rim and a flange formed on the check valve. The o-ring being spaced-apart from the rim of the end cap core.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates generally to systems for sealing access ports and other openings in piping systems and more particularly to an end cap cover for a check valve assembly where the end cap cover is held in place by a circumferential clamp. 
   It is known to seal the open ends of piping and ports formed in pipe fixtures using removable caps. In this regard, the end or port can be accessed by removing the cap for replacing the end cap with another fixture or for providing access to a space within the piping of fixture. End caps are used in fixtures such as check valve assemblies for sealing an access port formed in a check valve housing. Generally such end caps are metallic, and a gasket or o-ring for sealing is positioned between a flange formed on the end cap and a flange formed on the check valve assembly. 
   Conventional end caps are often attached to pipes by engaging retaining rings, clamps, cooperating threaded surfaces formed on the pipe end and on the cap, and the like. In each case the gasket or o-ring for sealing is positioned between the flange of the end cap and the flange of the fixture. 
   A problem with such known end caps is that in order for the gasket or o-ring to be sealingly engaged, the o-ring must be compressed between the flanges around the entire circumference of the end cap. Such uniform compression can be difficult to obtain. Another problem with known end cap sealing systems is that the end caps are metallic. Metallic end caps can be costly to manufacture and contribute significantly to the weight of the fixture, such as a check valve assembly, in which the end cap is being used. 
   BRIEF SUMMARY OF THE INVENTION 
   Accordingly, there is a need to provide an end cap sealing system that is lighter, less costly to manufacture, and more reliably sealed than known end cap sealing systems. 
   Therefore it is an object of the present invention to provide an end cap sealing system that includes an end cap having polymeric components. 
   Therefore it is an object of the present invention to provide an end cap sealing system that is lighter in weight than conventional end cap sealing systems. 
   Therefore it is an object of the present invention to provide a check valve assembly that is lighter in weight than conventional check valve assemblies. 
   Therefore it is an object of the present invention to provide an end cap sealing assembly having an end cap core that is non metallic. 
   Therefore it is an object of the present invention to provide an end cap sealing system having a gasket or o-ring for sealing that is spaced-away from flanges formed on an end cap such that the gasket or o-ring can engage an interior surface of the piping end or fixture being sealed. 
   Therefore there is provided an end cap sealing system for sealing an open piping end. The end cap sealing system includes an end cap having an end cap core. The end cap core has a generally cylindrical end with a circumferential groove formed around the exterior thereof and a closed end that defines a generally circular rim. An o-ring is positioned within the groove for sealingly engaging an interior wall of the piping open end. The end cap sealing system also includes a generally circular clamp having a channel formed therein for capturing the rim and a flange formed on the check valve. The o-ring being spaced-apart from the rim of the end cap core. 
   In accordance with one embodiment of the present invention, a generally circular clamp having a channel formed therein for capturing the rim and a flange formed on the open piping end is provided. 
   In accordance with another embodiment of the invention, the open piping end is formed on a fixture. 
   In accordance with another embodiment of the invention, the fixture is a check valve and the open piping end is an access port. 
   In accordance with another embodiment of the invention, the flange is formed around the access port and defines a surface that engages the lip of the end cap. 
   In accordance with another embodiment of the invention, the end cap includes a polymeric end cap core. 
   In accordance with another embodiment of the invention, a metallic end cap cover is provided. 
   In accordance with another embodiment of the invention, the end cap cover is attached to the end cap core by a screw. 
   In accordance with another embodiment of the invention, the end cap cover is attached to the end cap core by a valve having a portion that extends through the end cap core. 
   In accordance with another embodiment of the invention, there is provided a method for using an end cap sealing system to seal open piping end. A clamp and an end cap having an end cap core are provided. The end cap core has a generally cylindrical end with a circumferential groove formed around the exterior thereof and a closed end that defines a generally circular rim. An o-ring is positioned within the groove for sealingly engaging an interior wall of the open piping end. The end cap sealing system also includes a generally circular clamp having a channel formed therein for capturing the rim and a flange formed on the check valve. The o-ring being spaced-apart from the rim of the end cap core. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The subject matter that is regarded as the invention may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures in which: 
       FIG. 1  is a sectional side view of a check valve assembly that includes end cap covers according to one embodiment of the present invention; 
       FIG. 2  is a partial sectional view of the check valve assembly and an end cap as shown in  FIG. 1 ; 
       FIG. 3  is a top view of the end cap shown in  FIG. 2 ; 
       FIG. 4  is a perspective view of an end cap according to another embodiment of the present invention having a valve positioned therein; 
       FIG. 5  is a side view of the end cap shown in  FIG. 2 ; and 
       FIG. 6  is a top view of the end cap shown in  FIG. 2 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to the drawings wherein identical reference numerals denote the same elements throughout the various views,  FIG. 1  illustrates a check valve assembly  10  that includes two end caps  70 A and  70 B according to the present invention. The end caps  70 A and  70 B are substantially similar such that the end cap  70 B can be understood from a description of the end cap  70 A with the exception of an alternative configuration described further below. 
   The check valve assembly  10  includes a pair of check valves  30 A and  30 B positioned in series with each other. The check valves  30 A and  30 B are substantially the same such that the check valve  30 B can be understood with regard to the following description of the check valve  30 A. Each check valve  30  includes a housing  32  formed by walls  34 . An interior surface of the walls  34  define an interior region  36 . An inlet  38  and an outlet  42  are defined in the housing  32  for permitting fluid flow from an upstream side to a downstream side of the housing  32 . An access port  44  is defined in housing  32  for permitting access to the interior region  36 , and a flange  45  is formed around the access port  44  as described further below. A valve mechanism  46  is positioned within the interior region  36  for controlling fluid flow therethrough. In the illustrated embodiment, the valve mechanism  46  is a check valve. It is appreciated that various types of devices can be received within the interior region  36 . By way of example and not limitation, the types of flow control devices that could be received within interior region  36  include the following: various types of valves including swing-type check valves, flow meters, sample collection devices, sensors for monitoring fluid qualities, flow control devices, flow restrictors, and combinations thereof. The valve mechanism  46  includes a valve seat  48  positioned in the interior region  36  of the valve housing  32 , and a seal retainer  52  positioned in the interior region  36  downstream from the valve seat  48 . The seal retainer  52  is mounted on a stem  54 . 
   The stem  54  and the seal retainer  52  are axially movable away from the valve seat  48  in response to fluid flow from the inlet  38  to the outlet  42 , i.e., in a downstream direction. The seal retainer  52  and the stem  54  are also axially movable toward the valve seat  48  in response to fluid flow from the outlet  42  to the inlet  38 , i.e., in an upstream direction. The seal retainer  52  and the stem  54  are configured to be positioned in sealing engagement against the valve seat  48  in the absence of fluid flow. A plurality of springs  55  connect the stem  54  to the interior of the walls  34 . The springs  55  are positioned in radial opposition to one another, and each spring  55  has one end pivotally connected to the valve seat  48  and another end pivotally connected to the stem  54 . The springs  55  are configured to maintain the seal retainer  52  in sealing engagement with the valve seat  48  in the absence of fluid flow. 
   As can be seen in  FIG. 1 , the valve mechanism  46  is positioned within a cage  56  that is configured to be received by the interior region  36  through access port  44  and retained within region  36  by end cap  70 A. 
   Referring to  FIGS. 1 and 2 , the end cap  70 A is generally cup-shaped and includes an end cap core  72 A and a metallic end cap cover  110 . The end cap core  72 A has an open end  74  and a closed end  76  and is configured such that the open end  74  can be received within the access port  44  of the check valve  30 . The end cap core  72 A is oriented such that the open end  74  is oriented such that it is open toward the valve mechanism  46 . The end cap core  72 A is generally cylindrical around an axis near the open end  74 . An inner wall  82  is formed on the open end  74  and extends away from the open end  74  coaxial to the axis of the end cap core  72 A. A land area  84  is formed on inner wall  82 . An outer wall  86  is positioned concentrically with the inner wall  82  and extends from the end cap core  72 A further than the inner wall  82 . The inner wall  82  and the outer wall  86  together define an annular channel  88  that is configured to receive a gasket  92 . 
   The gasket  92  is generally circular and has an outer ring portion configured to be received within the annular channel  88 . An inner seal portion  96  extends from the ring portion of the gasket  92 , and is configured to extend across the land area  84  of the inner wall  82 . The inner wall  82 , the outer wall  86 , and the gasket  92  are configured such that the gasket  92  is operable to sealingly engage the cage  56  when the end cap  70 A is positioned within access port  44 . 
   Continuing to refer to  FIGS. 1 and 2 , a circumferential groove  102  is formed around the cylindrical portion of the end cap core  72 A. In the illustrated embodiment, the circumferential groove  102  is spaced-away from the open end  74  of the end cap core  72 A and from a rim  106  of the end cap core  72 A (described below). It should be appreciated that the groove  102  could be formed on the outer wall  86  of the end cap core  72 A. The groove  102  is configured to receive an o-ring  104 . In one embodiment, the o-ring  104  is formed of a resilient polymeric material such as EPDM. The o-ring  104  could also be formed of suitable sealing materials such as buna-N, silicone rubber, Viton™, and the like. 
   The end cap core  72 A flares outwardly to the rim  106  at a closed end  76  that is positioned opposite the open end  74 . The rim  106  extends around the entire circumference of the end cap core  72 A and has two opposed recesses  108  formed therein that are dimensioned to receive a tool such as a screw driver. In the illustrated embodiment, the closed end  76  is generally dome-shaped and extends away from the interior region  36 . It should be appreciated that the closed end  76  could be generally flat or formed such that it extends into the interior region  36  of housing  32 . 
   In the illustrated embodiment, the end cap core  72 A is formed of a polymeric material. By way of example and not limitation, the end cap core  72 A can be formed of one of Noryl™, a polysulfone, an acetal, a metal, a ceramic or a combination thereof. 
   The end cap cover  110  is configured to fit over the closed end  76  of the end cap core  72 A. In the illustrated embodiment, the end cap cover  110  closely conforms to the shape of the closed end  76 . As shown in  FIG. 3 , a screw  112  is provided to attach the end cap cover  110  to the end cap core  72 A in one embodiment. Referring to an alternative configuration shown in  FIG. 4 , a test cock  114  is attached to the end cap core  72  B of the end cap  70 B. A nut  116  is engaged with a portion of the test cock  114  that extends through the end cap cover  110 , and is received within a recess  118  formed in the end cap core  72 B and shown in  FIG. 6 . Respective portions of the test cock  114  and the end cap core  72 B are configured to capture the end cap cover  110  and to retain it against the end cap cover  110 . It should be appreciated that some embodiments of the present invention do not include an end cap cover  110 . In some embodiments end cap cover  110  is integrally formed with end cap  70 . 
   Referring now to  FIG. 3 , a clamp  122  is configured to capture the end cap  70 A and a flange  45  formed around the access port  44 . The clamp  122  is generally circular and has a first end  124  and a second end  126 . A groove  102  is formed on the interior of the clamp  122  and is configured to receive rim  106  of the end cap  70 A. A pin  128  is repositionably attached to first end  124  and is configured to engage second end  126  such that clamp  122  can be quickly secured around the flange  45  of the access port  44  and the rim  106  of the end cap  70 . In this manner, end cap  70  can be attached to housing  32  of the check valve  30 . 
   The present invention can be better understood from a description of the operation of end cap  70 . As indicated above, end cap  70  is used to seal openings in pipes, fixtures, or tubes such as the access port  44 . Prior to placing end cap  70  within access port  44 , an o-ring  104  is positioned with in groove  102  and a gasket  92  is positioned within channel  88 . In the illustrated embodiment, the valve mechanism  46  is positioned within cage  56  that is then placed within interior region  36  through access port  44 . After cage  56  and valve mechanism  46  are positioned within interior region  36 , end cap  70  is positioned such that open end  74  extends through access port  44  and o-ring  104  is in sealing engagement with walls  34 . As indicated above, o-ring  104  is formed of a material that is deformable for providing a sealing engagement between end cap  70  and walls  34 . When the end cap  70  is positioned within the access port  44 , the lip  106  is near the flange  45  of the access port  44 . 
   The clamp  122  is then place around end cap  70  and access port  44  such that both the flange  45  and the lip  106  are captured within channel  88 . The pin  128  is engaged with second end  126  such that clamp  122  is secured around the flange  45  of the access port  44  and the rim  106  of the end cap  70 . In this manner, end cap  70  is attached to housing  32  of the check valve  30 . 
   The foregoing has described an end cap sealing system for an check valve. While specific embodiments of the present invention have been described, it will be apparent to those skilled in the art that various modifications thereto can be made without departing from the spirit and scope of the invention. Accordingly, the foregoing description of the preferred embodiment of the invention and the best mode for practicing the invention are provided for the purpose of illustration only and not for the purpose of limitation.