Patent Publication Number: US-2005139266-A1

Title: Full-opening compact swing check valve

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This application claims the benefit of U.S. Provisional Application No. 60/528,783, filed Dec. 11, 2003, which is hereby incorporated by reference in its entirety for all purposes. 
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      This invention relates to a check valve. More specifically, the present invention relates to a check valve that can be fully opened.  
      2. Description of the Related Art  
      Compact manifold solutions, such as those used in oilfield operations, generally require compact valves. The overall length of a given valve with its weldable companion flanges is a significant determining factor in the overall size of a compact manifold. Swing check valves currently used in compact manifolds typically include two body penetrations in order to retain the flapper. Such body penetrations create undesirable potential leak paths.  
      Wafer-style swing check valves, such as a check valve  10  shown in  FIG. 1 - FIG. 2 , have been used for many years. The wafer-style valve  10  is mounted between two standard flanges  12 ,  14 , which have bores generally matching those of mating pipes  16 ,  18 , respectively. The flange bore  20  (shown in phantom in  FIG. 2 ) provides the cavity for a flapper  22  to swing open. This arrangement limits the size of the flapper  22 , thereby limiting the size of the check valve bore  24 . This reduced port, or valve bore  24 , precludes pigging of the flowline, which is the running of a device (i.e., a pig) within a pipeline to clean the interior surfaces of the pipeline or to perform other operations on the pipeline. The reduced port or valve bore  24  also creates a generally undesired pressure drop across the valve  10  during flow. Existing wafer-style swing check valves employ such a construction.  
      Fully welded swing check valves, with all body joints or penetrations welded and the flowlines also connected by welding, are also available. Fully welded valves minimize the overall length of the valve and eliminate undesirable body penetrations, but do not allow for valve maintenance. The valve may only be removed from the flowline for service by cutting the flowline. Easy valve removal and maintenance with minimal disruption of the flowline is a requirement for compact manifold valves.  
      The present invention is directed to overcoming, or at least reducing, the effects of one or more of the problems set forth above.  
     SUMMARY OF THE INVENTION  
      In one aspect of the present invention, a check valve is provided. The check valve includes a body defining a flow bore therethrough, a slot, and a cavity extending from the flow bore and a flapper shoe retained in the slot. The check valve further includes a flapper operatively mounted to the flapper shoe such that, when closed, flow is inhibited through the flow bore and, when opened, the flapper is completely received in the cavity.  
      In another aspect of the present invention, a check valve assembly is provided. The check valve assembly includes a valve body defining a flow bore therethrough and a flapper operatively mounted within the valve body such that, when closed, flow is inhibited through the flow bore and, when opened, flow is uninhibited through the flow bore. The check valve assembly further includes a tailpiece attached to the valve body, the tailpiece defining a flow bore therethrough in fluid communication with the flow bore of the valve body and defining a cavity extending from its flow bore for completely receiving the flapper when opened.  
      In yet another aspect of the present invention, a check valve assembly is provided. The check valve assembly includes a first flange defining a flow bore therethrough and a flapper operatively mounted within the first flange such that, when closed, flow is inhibited through the flow bore and, when opened, flow is uninhibited through the flow bore. The check valve assembly further includes a second flange attached to the valve body, the second flange defining a flow bore therethrough in fluid communication with the flow bore of the first flange and defining a cavity extending from its flow bore for completely receiving the flapper when opened.  
      In another aspect of the present invention, a valve assembly is provided. The valve assembly includes a valve defining a flow bore therethrough and a check valve wafer attached to the valve and defining a flow bore therethrough in fluid communication with the valve&#39;s flow bore such that, when the check valve wafer is in a closed state, flow is inhibited through the check valve flow bore and, when opened, flow is uninhibited through the check valve flow bore.  
      In yet another aspect of the present invention, a valve assembly is provided. The valve assembly includes a valve comprising a body defining a flow bore therethrough and a flapper operatively mounted within the body such that, when closed, flow is inhibited through the flow bore and, when opened, flow is uninhibited through the flow bore. The valve assembly further includes a tailpiece attached to the body, the tailpiece defining a flow bore therethrough in fluid communication with the flow bore of the body and defining a cavity extending from its flow bore for receiving the flapper when opened. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The invention may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements, and in which:  
       FIG. 1  is a side view of a conventional check valve;  
       FIG. 2  is a cross-sectional, side view of the check valve of  FIG. 1 ;  
       FIG. 3 a  partial, cross-sectional side view of one illustrative embodiment of a check valve assembly according to the present invention;  
       FIG. 4  is a partial, cross-sectional end view of the check valve assembly of  FIG. 3  taken along the line  4 - 4  in  FIG. 3 ;  
       FIG. 5  is an enlarged view of a portion of the view of  FIG. 4 ;  
       FIG. 6  is a cross-sectional, side view of a first alternative illustrative embodiment of a check valve assembly according to the present invention;  
       FIG. 7  is cross-sectional, side view of a second alternative illustrative embodiment of a check valve assembly according to the present invention;  
       FIG. 8  is a cross-sectional, side view of a third alternative illustrative embodiment of a check valve assembly according to the present invention;  
       FIG. 9  is a partial, cross-sectional side view of a ball valve according to the present invention incorporating the check valve wafer of  FIG. 3 ; and  
       FIG. 10  is a partial, cross-sectional side view of a ball valve according to the present invention incorporating the components of the check valve wafer of  FIG. 3 . 
    
    
      While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.  
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS  
      Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developer&#39;s specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.  
      The present invention will now be described with reference to the attached figures. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase.  
      In the specification, reference may be made to the direction of fluid flow between various components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the present application, the device and systems described herein may be positioned in any desired orientation. Thus, the reference to the direction of fluid flow should be understood to represent a relative direction of flow and not an absolute direction of flow. Similarly, the use of terms such as “above,” “below,” or other like terms to describe a spatial relationship between various components should be understood to describe a relative relationship between the components as the device described herein may be oriented in any desired direction.  
       FIG. 3 - FIG. 5  depict a first illustrative embodiment of a check valve assembly  100  according to the present invention. The check valve assembly  100  comprises a valve body  105  and an upstream flange  110 , which are attached to downstream flange or tailpiece  115  via capscrews  120 . The scope of the present invention, however, encompasses other ways of mechanically fastening the valve body  105  and the upstream flange  110  to the tailpiece  115 . A valve seat  125  and a flapper shoe  130  are disposed within valve body  105 . In the illustrated embodiment, the flapper shoe  130  is retained in the valve body  105  by setscrews  135  (shown in  FIG. 4 - FIG. 5 ), but may be retained by other means. A flapper  140  is hingedly mounted on the flapper shoe  130  via a flapper pin  145  (best shown in  FIG. 4 - FIG. 5 ), which may comprise part of the flapper  140  or may be a separate element. In some embodiments, the flapper  140  is biased towards a closed position against the valve seat  125 , via a flapper spring  150  (best shown in  FIG. 5 ). The flapper spring  150 , however, may be omitted in some embodiments. In the illustrated embodiment, one or more seals  155  are provided on the valve seat  125  for sealing between the valve seat  125  and the flapper  140  when the flapper  140  is closed. Alternatively, the one or more seals  155  may be provided on the flapper  140  or may be omitted altogether. O-ring flange seals  160  are provided between the valve body  105  and the upstream flange  110 , as well as between the valve body  105  and the tailpiece  115 . One or more O-ring seals  165  are provided between valve seat  125  and valve body  105 . Sealing elements other than O-rings, however, may be used at any of these sealing locations.  
      The function of the valve of the present invention is to prevent flow in one direction while allowing flow in the other direction. The flapper  140  swings open when flow moves from left to right (as depicted in  FIG. 3 ) and swings closed when flow reverses (as shown in  FIG. 6 ). The flapper spring  150 , when present, urges the flapper  140  toward a closed position because the center of gravity of the flapper  140  may be upstream of the flapper pin  145  when the flapper  140  is in its closed position. The valve assembly  100  comprises the upstream flange  110 , a valve wafer  170 , and the tailpiece  115 . In the illustrated embodiment, the valve wafer  170 , in turn, comprises the valve body  105 , the valve seat  125 , the flapper  140 , the flapper shoe  130 , the flapper pin  145 , the flapper spring  150 , and the setscrews  135 . As noted above, in the illustrated embodiment, the upstream flange  110 , the valve wafer  170 , and the tailpiece  115  are connected by capscrews  120 . Alternatively, the upstream flange  105 , the valve wafer  170 , and the tailpiece  115  may be connected by studs extending from either the upstream flange  105 , the valve body  105 , or the tailpiece  115  and nuts (not shown). In the illustrated embodiment, the bolts or screws  120  may be installed with their fastener heads  175  adjacent the upstream flange  110  or the tailpiece  115 . The bolts or screws  120  may pass through clearance holes in the valve body  105 , as shown, or be installed in threaded holes in the valve body  105  and pass through clearance holes in the upstream flange  110  and tailpiece  115 , as illustrated in  FIG. 6 .  
      The complete valve assembly  100 , as illustrated in  FIG. 3 - FIG. 6 , is designed such that it may be welded into a flowline, such that the valve assembly can be serviced by removing the capscrews  120  and sliding the valve body  105  and its internal components (i.e., the valve wafer  170 ) out from between the upstream flange  110  and the tailpiece  115 . Having the three separate pieces (i.e., the upstream flange  105 , the valve wafer  170 , and the tailpiece  115 ) allows the placement of all sensitive items, such as seals, within the valve body  105 , which is generally not present at the time of welding. In the illustrated embodiment, the upstream flange  110  and the tailpiece  115  are single components that do not include items sensitive to the heat of welding or stress-relieving. The upstream flange  110  and tailpiece  115  may include weld preparations (e.g., bevels  178 , grooves, etc.) that are ready for welding to the mating pipe.  
      In the embodiments illustrated in  FIG. 3 - FIG. 6 , the tailpiece  115  also defines a cavity  180  that accepts the flapper  140  when it is in its fully-opened position. This allows the flapper  140  to swing fully out of the flow path, minimizing the pressure drop across the valve, and eliminating interference with operations such as pigging. Note that, while the cavity  180  is illustrated in the accompanying figures as extending radially around the entire flow bore  190 , concentric with the center line  188 , the present invention is not so limited. Rather, the cavity  180  may be sized only to completely contain the flapper  140  when in its fully-opened position.  
      The valve seat  125  may be integral with the valve body  105  or may be replaceable, as shown. In the event the valve seat  125  is integral with the valve body  105 , the seat to body seal  165  is omitted. Note that the valve seat  125  does not contribute to sealing the valve shell (i.e., to prevent external leakage from or to the valve assembly  100 ) but only serves a sealing function when the valve assembly  100  is closed. When flow reverses and the valve assembly  100  closes, the flapper  140  contacts the seat  125  and seals through the seat to flapper seal  155 . The seat  125  seals to the valve body  105  through the seat to body seal  165 . The flapper  140  pivots about the flapper pin  145 . The flapper pin  145  is rotatably retained by the flapper shoe  130 . The optional spring  150  assists the flapper  140  by providing a closing moment that biases the flapper towards the closed position.  
      The flapper shoe  130  and its mating slot in the valve body  105  provide a simple means for retaining the flapper pin  145  without making body pressure-boundary penetrations. In the illustrated embodiment, the flapper shoe  130  comprises a portion of a ring that fits in an internal groove  185  defined by the valve body  105 . The flapper shoe  130  is restrained from moving radially outwardly, upstream, or downstream by the groove  185 . The flapper shoe  130  is restrained from movement radially inwardly or tangentially about the valve centerline  188  by the setscrews  135 . The setscrews  135  may be threaded through the flapper shoe  130  and into blind holes in the valve body  105 . Setscrews, capscrews, pins, keys, or other such locking devices may be used to serve the same purpose as the setscrews  135 . By preventing radially inward movement, the setscrews  135  keep the flapper shoe  130  from becoming dislodged.  
      The setscrews  135  fit completely inside a theoretical circle having its center at the center of the flow bore  190  (i.e., at the valve centerline  188 ) and passing just outboard of flapper arms  192  when the flapper  140  is in its fully-opened position. By keeping the flapper shoe locking means (e.g., the setscrews  135 ) inside this circle, the sealing diameter of the tailpiece connection (i.e., the connection between the valve wafer  170  and the tailpiece  115 ) is minimized. Keeping this sealed opening as small as possible is significant because the total bolt strength required for the connection is directly determined by the sealed diameter of this joint. A larger opening would require more or larger capscrews  120 , causing the outer diameter of the assembly to become larger.  
      By placing the downstream connection close to the flapper pin  145 , the overall length of the valve body  105  is minimized. The length of the tailpiece  115  is generally slightly longer than a comparable, conventional weldneck flange. The result is the shortest complete valve assembly (i.e., upstream flange  110 , valve wafer  170 , and tailpiece  115 ) that is suitable for welding in-line, and also allows easy maintenance and provides a full-opening flapper  140  suitable for pigging and other full-bore operations. Placing the downstream connection (i.e., the connection between the valve wafer  170  and the tailpiece  115 ) adjacent the flapper pin  145  also allows easier machining access for detail machining of the holes to accept the setscrews  135 . These holes would be much more difficult to machine, if not impractical, if the downstream connection were smaller and further downstream.  
      In total, there are two seals in the illustrated embodiment to prevent external leakage, compared to five on some existing valves. The two body penetrations required for installing the flapper pin in existing designs have been completely eliminated in the present invention. A third seal is eliminated by placing the replaceable valve seat  125  completely inside the valve body  105 , whereas some existing valve designs have a seal, disposed between the valve body and valve seat, that is exposed to the valve external environment. The combined length of the valve body  105  and the tailpiece  115  is very nearly the length of conventional valve bodies alone in existing compact swing check valves. In some embodiments, the upstream flange  105  is generally unchanged from that of existing valves.  
      While the embodiments illustrated in  FIG. 3  and  FIG. 6  comprise upstream flanges  110  and tailpieces  115  adapted to be welded to sections of pipe, such as in a pipeline, the present invention is not so limited. Rather, embodiments of the present valve assembly may be flange-bolted or otherwise mechanically fastened to piping sections. Moreover, the valve wafer  170  of  FIG. 3  and  FIG. 6  may be incorporated into either an upstream flange or a tailpiece.  FIG. 7  depicts one such embodiment according to the present invention, wherein a valve assembly  200  comprises an upstream flange  205  attached directly to a tailpiece  110 . In this embodiment, the components of the valve wafer  170  (i.e., the valve body  105 , the valve seat  125 , the flapper  140 , the flapper shoe  130 , the flapper pin  145 , the flapper spring  150 , and the setscrews  135  of  FIG. 3 - FIG. 5 ) are incorporated into the upstream flange  205  and operate in the same manner as discussed above. The tailpiece  110  of  FIG. 7  defines the cavity  180  for receiving the flapper  140  when in the open position and is configured to be welded to a piping section. The upstream flange  205  is adapted to be bolted to a piping or other flow section. Alternatively, the tailpiece  110  may be configured to be flange-bolted to a piping or other flow section.  
       FIG. 8  depicts another illustrative embodiment of a valve assembly  300  according to the present invention. This embodiment generally corresponds to that of  FIG. 3  and  FIG. 6 , except that the tailpiece  305  is adapted to be flange-bolted to a piping or other flow section, rather than being welded to a piping section. Alternatively, the upstream flange  105  may be configured to be flange-bolted and, in some embodiments, may incorporate the components of the valve wafer  170  therein.  
      The embodiments discussed to this point have been generally directed to a stand-alone check valve, in that the check valve assemblies  100 ,  200 ,  300  are not shown in combination with other flow control devices. The present invention, however, is not so limited. Rather, the valve wafer  170  may be incorporated with other valve assemblies or other flow control assemblies.  FIG. 9 - FIG. 10  illustrate the valve wafer  170  incorporated into ball valves  400 ,  500 . For example, as shown in  FIG. 9 , the valve wafer  170  is attached an inlet flange  405  of the ball valve  400 . Note that the inlet flange  405  may be adapted to receive fastening members (e.g., bolts  410  or the like) or it may comprise studs extending therefrom for attaching the valve wafer  170  thereto. In the illustrated embodiment, a body  415  of the ball valve  400  defines a bore  420  that includes a cavity  425  for receiving the flapper  140  when in its open position.  
      Alternatively, as depicted in  FIG. 10 , components of the valve wafer  170  may be incorporated into an output side  505  of the ball valve  500  in the same way that the components of the valve wafer  170  are incorporated into the upstream flange  205  of  FIG. 7 . In this embodiment, a tailpiece  510  defines a bore  515  including a cavity  520  for receiving the flapper  140  when in its open position. Alternatively, the valve wafer  170  may be attached to the output side of the ball valve  500 , rather than being incorporated therein.  
      While  FIG. 9 - FIG. 10  illustrate ball valves  400 ,  500  comprising the valve wafer  170  or the components of the valve wafer  170  incorporated therein, the present invention is not so limited. Rather, the scope of the present invention encompasses the valve wafer  170 , or the components thereof, in combination with various types of flow devices, such as other types of valves, wellhead fittings, tees, elbows, crosses, pipe connectors, pressure vessels, pig launchers, pig receivers, flow headers, and the like.  
      In one particular embodiment of the present invention, a check valve includes a body defining a flow bore therethrough, a slot, and a cavity extending from the flow bore and a flapper shoe retained in the slot. The check valve further includes a flapper operatively mounted to the flapper shoe such that, when closed, flow is inhibited through the flow bore and, when opened, the flapper is completely received in the cavity.  
      In another particular embodiment of the present invention, a check valve assembly includes a valve body defining a flow bore therethrough and a flapper operatively mounted within the valve body such that, when closed, flow is inhibited through the flow bore and, when opened, flow is uninhibited through the flow bore. The check valve assembly further includes a tailpiece attached to the valve body, the tailpiece defining a flow bore therethrough in fluid communication with the flow bore of the valve body and defining a cavity extending from its flow bore for completely receiving the flapper when opened.  
      In yet another particular embodiment of the present invention, a check valve assembly includes a first flange defining a flow bore therethrough and a flapper operatively mounted within the first flange such that, when closed, flow is inhibited through the flow bore and, when opened, flow is uninhibited through the flow bore. The check valve assembly further includes a second flange attached to the valve body, the second flange defining a flow bore therethrough in fluid communication with the flow bore of the first flange and defining a cavity extending from its flow bore for completely receiving the flapper when opened.  
      In another particular embodiment of the present invention, a valve assembly includes a valve defining a flow bore therethrough and a check valve wafer attached to the valve and defining a flow bore therethrough in fluid communication with the valve&#39;s flow bore such that, when the check valve wafer is in a closed state, flow is inhibited through the check valve flow bore and, when opened, flow is uninhibited through the check valve flow bore.  
      In yet another particular embodiment of the present invention, a valve assembly includes a valve comprising a body defining a flow bore therethrough and a flapper operatively mounted within the body such that, when closed, flow is inhibited through the flow bore and, when opened, flow is uninhibited through the flow bore. The valve assembly further includes a tailpiece attached to the body, the tailpiece defining a flow bore therethrough in fluid communication with the flow bore of the body and defining a cavity extending from its flow bore for receiving the flapper when opened.  
      This concludes the detailed description. The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.