Abstract:
In accordance with one embodiment of the present invention, a seal for a surge relief valve includes a) a valve housing having a flow inlet and a flow outlet; b) an annular retainer for coupling a plug to an interior of the valve housing, the retainer having a first end oriented toward the flow inlet and a second end remote therefrom; c) the plug having a first end oriented toward the flow inlet and a second end remote therefrom, the plug having a mating junction for coupling with the second end of the retainer, the plug having a first countersink, a second countersink, a first lip defined between the first and second countersinks and a second lip adjacent the second countersink; and d) an annular plug seal having a first end oriented toward the flow inlet and a second end remote from the first end for mating with the second countersink and a lip that abuts the second end of the retainer.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to seals for industrial fluid flow applications. More particularly, the present invention relates to seals for surge relief valves. 
     BACKGROUND OF THE INVENTION 
     Oil and gas pipelines are extremely important for delivery of oil and gas from the source to the consumer. Such pipelines must accommodate large quantities of oil and gas, be able to withstand various pressures, and are at times, subject to surges of pressure. Pressure surges also known as pressure surge waves or “water hammers,” are caused by various factors, such as, rapid opening or closure of a valve or starting or stopping of a pump. Thus, pipelines are equipped with surge relief valves to accommodate and handle pressure surges. 
     Surge relief valves must respond very quickly and smoothly to pressure surges. The surge relief valves must open quickly to track the large initial pressure rise and then close in direct response to pressure decrease at the valve inlet, relieving sufficient fluid volume to eliminate the surge. The excess fluid is typically diverted to a storage vessel and then returned to the product line. 
     It has been known to provide a dynamically balanced-plug assembly that slides back and forth easily and rapidly to open, close and throttle. Pressure in the plug cavity closes the valve while lack of pressure opens the valve. Typically, the cavity behind the valve plug is filled with nitrogen gas to affect proper relief set pressure of the valve and hold the valve&#39;s internal plug or piston, tight against its seat. This cavity loading force seats the valve and opposes the force generated by line pressure in front of the valve. The valve remains closed until the surge wave pressure exceeds the force behind the plug (set pressure). The surge relief valve then opens to track the surge. 
     Thus, the seals in the valves must be seated properly and provide a tight seal, preventing fluid flow leaks under both steady state conditions and surges. In order to properly function, it is advantageous for the mating surfaces within the valve to engage with a relatively high degree of precision without slippage or gaps. 
     Oftentimes, it is difficult to provide a seal that functions across a range of pressures and temperatures, is compatible with a variety of fluids, allows the valve to be opened and closed with minimal effort, and is sufficiently wear resistant to withstand repeated opening and closing operations. Accordingly, it is desirable to provide a seal for surge relief valves, and all valves in general, that can withstand high pressure applications, operate over long periods of time, and forms a tight seal that reduces or eliminates fluid leak around the seal. 
     SUMMARY OF THE INVENTION 
     The foregoing needs are met, to a great extent, by the present invention, which provides a seal for surge relief valves, and all valves in general, that can withstand high pressure applications, operate over long periods of time, and forms a tight seal that reduces or eliminates fluid leak around the seal. 
     In accordance with one embodiment of the present invention, a seal for a surge relief valve includes a) a valve housing having a flow inlet and a flow outlet; b) an annular retainer for coupling a plug to an interior of the valve housing, the retainer having a first end oriented toward the flow inlet and a second end remote therefrom; c) the plug having a first end oriented toward the flow inlet and a second end remote therefrom, the plug having a mating junction for coupling with the second end of the retainer, the plug having a counterbore, a groove, a first lip defined between the counterbore and groove and a second lip adjacent the groove; and d) an annular plug seal having a first end oriented toward the flow inlet and a second end remote from the first end for mating with the groove and a lip that abuts the second end of the retainer. 
     In accordance with another embodiment of the present invention, a seal for a valve includes a) a plug seal having an annular shape and a generally rectangular profile, comprising a top surface, a bottom surface remote from the top surface, an interior side and an exterior side remote from the interior side, the top surface having a protrusion, the exterior side having a frusto-conical lip, and a bump defined by a junction of the top surface and the interior side; and b) a plug for mating with the plug seal, the plug comprising a first lip with a slope, a second lip and a depression defined between the first and second lips, wherein the slope of the first lip mates with the bump of the plug seal, the depression of the plug mates with the bottom surface of the plug seal and the second lip mates with the frusto-conical lip of the plug seal. 
     In accordance with yet another embodiment of the present invention, a method for sealing a surge relief valve includes a) providing a plug seal having an annular shape and a generally rectangular profile, comprising a top surface, a bottom surface remote from the top surface, an interior side and an exterior side remote from the interior side, the top surface having a protrusion, the exterior side having a frusto-conical lip and a bump defined by a junction of the top surface and the interior side; b) mating with the plug seal, a plug having a generally cylindrical shape, a first end and a second end remote from the first end, the plug first end comprising a first lip with a slope, a second lip and a depression defined between the first and second lips, wherein the slope of the first lip mates with the bump of the plug seal, the depression mates with the bottom surface of the plug seal and the second lip mates with the frusto-conical lip of the plug seal; and c) mating with the plug seal a seal spacer, the seal spacer having an annular shape and a generally rectangular profile, comprising a top surface, a bottom surface remote from the top surface, the bottom surface having a depression formed therein for mating with the protrusion of the plug seal, the seal spacer having an interior surface and an exterior surface remote from the interior surface. 
     There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto. 
     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. 
     As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross sectional view illustrating a surge relief valve and its components according to a preferred embodiment of the present invention. 
         FIG. 2  is a cross sectional view of a plug of the surge relief valve depicted in  FIG. 1 . 
         FIG. 3  is a detailed cross sectional view of a portion of the plug depicted in  FIG. 2 . 
         FIG. 4  is a detailed cross sectional view of the surge relief valve of  FIG. 1 . 
         FIG. 5  is a cross sectional view of a seal retainer of the surge relief valve of  FIG. 1 . 
         FIG. 6A  is a cross sectional view of a seal spacer of the surge relief valve depicted in  FIG. 1 . 
         FIG. 6B  is a detailed view of the seal spacer depicted in  FIG. 6A . 
         FIG. 7A  is a cross sectional view of a retainer of the surge relief valve of  FIG. 1 . 
         FIG. 7B  is a detailed view of the retainer depicted in  FIG. 7A . 
         FIG. 8A  is a cross sectional view of a plug seal of the surge relief valve of  FIG. 1 . 
         FIG. 8B  is a detailed view of the plug seal depicted in  FIG. 8A . 
     
    
    
     DETAILED DESCRIPTION 
     The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. An embodiment in accordance with the present invention provides a seal for surge relief valves, and valves in general, that can withstand high pressure applications, operate over long periods of time, and form a tight seal that reduces or eliminates fluid leak around the seal. 
       FIG. 1  is a cross-sectional view of a surge relief valve in accordance with an embodiment of the present invention. The valve  10  includes a valve body  12 , a plug  14  and a retainer  16  that maintains the plug  14  in place. The direction of fluid flow is indicated with an arrow as illustrated. 
       FIG. 2  is a cross sectional view of the plug  14  of  FIG. 1 . The plug  14  has a first end  18  and a second end  20  remote therefrom. The first end  18  has a frusto-conical shape with a generally convex face  22  facing or oriented toward the direction of fluid flow. Further, the plug  14  has a generally cylindrical plug housing  24  disposed between the first and second ends  18 ,  20  respectively. A junction point  26  exists where the first end  18  meets the plug housing  24 . The junction point  26  provides a location where the retainer  16  mates with the plug  14 , as will be discussed in greater detail below. Although reference is made to “a” junction point  26 , it is noted that the term “a” is made with reference only to the figures. Because the plug  14  is generally cylindrical and the retainer  16  is an annular structure, the junction point  26  refers to a profile location where the retainer  16  and plug  14  mate along their respective circumferential surfaces and is not a single point in actuality. 
       FIGS. 3 and 4  are detailed views of the junction point  26  of  FIG. 1 . The junction point  26  includes various components that function to seal and retain the plug  14  within the valve  10  and prevent fluid from leaking from the valve  10 . The plug  14  includes a counterbore  28  and a groove  30 . The counterbore  28  is sized and configured to mate with a bolt  32 . The groove  30  is sized and configured to mate with a plug seal  34 . Between the counterbore  28  and the first end  18  is a seat  36  for mating with a seal spacer  38  and a seal retainer  40 . 
     Defined between the counterbore  28  and groove  30  respectively, is a first lip  42  that has a first slope  44  angled toward the counterbore  28 . Further, the plug  14  includes a second lip  46  that is configured to mate with both the plug seal  34  and the retainer  16 . A second slope  48  is defined beyond the second lip  46  toward the housing  24  of the plug  14 . This second slope  48  contacts the retainer  16  and is angled toward the first end  18 . 
       FIG. 5  is a cross sectional view of the seal retainer  40  depicted in  FIGS. 3 and 4 . The seal retainer  40  is an annular structure and has a plurality of bores  50  disposed periodically through the seal retainer  40 . The seal retainer bores  50  allow for the bolt  32  to pass through the bores  50  to fasten the seal retainer  40  to the plug  14 . 
       FIG. 6A  is a cross sectional view of the seal spacer  38  according to an embodiment of the present invention. The seal spacer  38  is annular in geometry and has a plurality of bores  52  disposed about the seal spacer  38 . The seal spacer bores  52  allow for the bolt  32  to pass through the bores  52 , allowing the bolt  32  to fasten the seal retainer  40  and the seal spacer  38  to the plug  14 . 
       FIG. 6B  is a detailed profile view of the seal spacer  38 . The seal spacer  38  has a first planar surface  54  that contacts the seal retainer  40 . Further, the seal spacer  38  includes a second planar surface  56  remote from the first planar surface  54 . The second planar surface  56  has a depression  58  for mating with the plug seal  34  as will be described below. Lastly, the seal spacer  38  has an exterior seal spacer wall  60  that contacts the retainer  16  and an interior seal spacer wall  62 , remote from the exterior seal spacer wall  60 , that contacts the seat  36  of the plug  14 . Further, the interior seal spacer wall  62  includes a sloped surface positioned at an angle to the first end  18  for easily sliding the seal spacer into place. 
       FIG. 7A  is a cross sectional view of the retainer  16 , according to an embodiment of the present invention. The retainer  16  has an annular shape with a first end  62  facing or oriented toward the fluid flow and a second end  64  remote therefrom. Further, the retainer  16  has an exterior wall  66  and an interior wall  68 . The interior wall  68  contacts the seal retainer  40 , the seal spacer  38  and the plug seal  34  while the exterior wall contacts the valve body  12 . 
       FIG. 7B  is a detailed view of the retainer second end  64 , where the exterior and interior retainer walls  66 ,  68  respectively, are visible. The retainer second end  64  has a planar wall  70  and a first retainer sloped wall  72  and a second retainer sloped wall  74 . The first retainer sloped wall  72  extends at an angle from the retainer planar wall  70  toward the second retainer sloped wall  74 . The second retainer sloped wall  74  extends at an angle toward the retainer interior wall  68 . The first and second retainer sloped walls  72 ,  74  respectively, and a portion of the retainer interior wall  68  mate against the plug  14  and in particular, against the second lip  46  of the plug  14 . 
       FIG. 8A  is a cross sectional view of the plug seal  34 , according to an embodiment of the present invention. The plug seal  34  also has an annular shape.  FIG. 8B  is a detailed cross sectional view of the plug seal  34 . Generally, the plug seal  34  includes a first end  76  facing or oriented toward the direction of fluid flow and a second end  78 , remote from the first end  76 . Further, the plug seal  34  includes a first plug seal interior wall  80 . Proceeding in a clockwise fashion around the structure, the plug seal  34  includes a plug seal second end wall  82  perpendicular to the plug seal interior wall  80 . The plug seal  34  further includes plug seal exterior wall  84  remote from and parallel to the plug seal interior wall  80 . A plug seal lip  86  protrudes from the plug seal exterior wall  84 . The plug seal lip  86  includes a generally frusto-conical shape, having a planar surface  88  disposed between a first angled wall  90  and a second angled wall  92 . The planar surface  88  of the plug seal lip  86  is parallel to the plug seal interior wall  80 . A plug seal first seat  94  is defined by the junction of the plug seal exterior wall  84  and the plug seal lip  86 . 
     The plug seal first end  76  includes a protrusion  96 . The plug seal protrusion  96  includes a protrusion first wall  98  and a protrusion second wall  100  remote therefrom. The protrusion first and second walls  98 ,  100 , respectively, are parallel to the plug seal interior wall  80 . Disposed between the protrusion first and second walls  98 ,  100 , is a plug seal first end wall  102  that is parallel to the plug seal second end wall  82 . The plug seal  34  includes a plug seal second seat  104  formed at the junction of the plug seal lip  86  and the plug seal protrusion  96 . 
     Further, the plug seal  34  first end  76  has a depression  106 . The protrusion second wall  100  defines the depression  106  perpendicular to the protrusion second wall  100  and parallel to the plug seal second end wall  82 . The plug seal first end  76  further includes a generally triangular bump  108 . The bump has a first bump wall  110  parallel to the plug seal interior wall  80 . The bump  108  further includes a bump second wall  112  perpendicular to the bump first wall  110  and a bump third wall  114  disposed at an angle toward the plug seal interior wall  80 . At the junction of the bump second wall  112  and the bump third wall  114  is a rounded corner  116 . The angle θ between bump second wall  112  and the bump third wall is about 40° to about 50°, and preferably about 45°. Lastly, a junction between the bump third wall  114  and the plug seal interior wall  80  defines a plug seal third seat  118 . 
     There has thus been provided a detailed description of several components of a surge valve. In operation and with reference to  FIG. 4 , it can be seen that once the plug  14  is coupled to the valve  10  the plug seal  34  is coupled to the plug  14 . The second plug seal wall  82  mates with the groove  30  of the plug  14 . The plug seal bump  108  mates with the first lip  42  of the plug  14 . The angle of the first slope  44  of the first lip  42  of the plug  14  is such that it accommodates the angle of the bump third wall  114  of the plug seal  34 . 
     Further, the plug seal lip  86  rests against the second lip  46  of the plug  14  and abuts the retainer  16  at the retainer interior wall  68 . The angles of the first and second angled walls  90 ,  92  respectively, form a small gap between the plug seal lip  86  and the retainer interior wall  68 . When pressed tightly, the planar surface  88  of the plug seal  34  deforms and takes up the gap formed by the first and second angled walls  90 ,  92  allowing for a fluid tight seal. Further, this gap also prevents any shearing of the plug seal  34 . 
     Next, the seal spacer  38  is placed against the plug seal  34  such that depression  58  of the seal spacer  38  mates with the plug seal first end protrusion  96  and the plug seal bump  108  contacts and abuts the second planar surface  56  of the seal spacer  38 . Next, the seal retainer  40  is placed adjacent the seal spacer  38  such that the seal retainer  40  abuts and contacts against the first planar surface  54  of the seal spacer  38 . Once the seal retainer bores  50  and the seal spacer bores  52  align with the counterbore  28  of the plug  14 , the bolt  32  is slid through the bores  50 ,  52  and into the first connecting sink  28  to fasten the seal retainer  40  and the seal spacer  38  to the plug  14 . In this fashion, the seal spacer  38  is captured and also retained in place. The generally staggered formation of the plug  14 , the plug seal  34  and the seal spacer  38  combine to secure these components in a very tight manner to reduce or eliminate fluid leakage. 
     The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.