Abstract:
Apparatus for controlling a pressurized fluid in a piping network, and method for making the same. In accordance with some embodiments, a substantially cylindrical body has an annular wall surrounding a central axis with opposing first and second ends and at least one pass-through aperture extending through a medial portion of the wall. An annular valve seat is nested within a first end of the body. A moveable piston is aligned within the body along the central axis, the piston having a sealing surface adapted to contactingly engage an inner annular surface of the valve seat to establish a fluidic seal. The body, valve seat and piston form a valve insert for a valve housing.

Description:
RELATED APPLICATIONS 
     The present application makes a claim of domestic priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/525,569 filed Aug. 19, 2011. 
    
    
     BACKGROUND 
     Pressurized fluid systems are often used to transport and direct a pressurized fluid, such as liquid or gaseous state hydrocarbons, steam, water, etc., through a piping network. A variety of valve configurations can be used to direct and condition the fluidic flow through the system, such as pressure relief valves, emergency shutdown valves, blowdown valves, flapper valves, ball valves, pressure reducing valves (chokes), back pressure valves, pressure regulating valves, etc. 
     SUMMARY 
     Various embodiments of the present disclosure are generally directed to an apparatus for controlling a pressurized fluid in a piping network, and a method for making the same. 
     In accordance with some embodiments, a substantially cylindrical body has an annular wall surrounding a central axis with opposing first and second ends and at least one pass-through aperture extending through a medial portion of the wall. An annular valve seat is nested within a first end of the body. A moveable piston is aligned within the body along the central axis, the piston having a sealing surface adapted to contactingly engage an inner annular surface of the valve seat to establish a fluidic seal. The body, valve seat and piston form a valve insert for a valve housing. 
     These and various other features and advantages of the various embodiments disclosed herein can be understood from a review of the following detailed description section and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  shows a normally closed pressure relief valve constructed and operated in accordance with various embodiments. 
         FIG. 2  shows the valve of  FIG. 1  in an open position. 
         FIGS. 3A-3B  are isometric and cross-sectional exploded views of a valve insert of the valve of  FIGS. 1 and 2 . 
         FIG. 4  depicts an alternative pressure relief valve configured as a pressure differential valve. 
         FIG. 5  illustrates insertion of the valve insert of  FIGS. 3A-3B  into a housing of the valve of  FIGS. 1-2 . 
         FIG. 6  is a schematic representation of axial misalignment that can be accommodated between the valve insert and the housing. 
         FIG. 7  depicts another normally closed pressure relief valve that uses the valve insert in accordance with various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Without limitation, various embodiments of the present disclosure are generally directed to a valve insert for use in a valve assembly, such as but not limited to a pressure relief valve. As explained below, the valve insert may be assembled and inserted into an interior chamber in a valve assembly housing. The provision of a relatively loose spacing between the valve insert and the interior sidewalls of the housing chamber allows for easy manufacture and reliable operation. 
       FIG. 1  shows a cross-sectional elevational representation of an exemplary valve assembly  100 , characterized without limitation as a normally closed pressure relief valve. The valve  100  includes a rigid housing  102  with an inlet port  104  and an outlet port  106 . A medial chamber  107  is formed by an annular interior sidewall  108 , with the medial chamber being in fluidic communication between the respective inlet and outlet ports  104 ,  106 . The valve is characterized as a “90 degree valve” or a “right angle valve” on the basis that the outlet port  106  extends in a direction that is nominally 90 degrees with respect to the inlet port  104 . 
     A valve insert is generally denoted at  110 . The valve insert  110  is a self-contained, removably replaceable operational module. During manufacturing, the valve insert  110  can be assembled in a separate subassembly operation, and thereafter placed into the interior chamber  107  of the housing  102 . Valve inserts with different configurations can be respectively placed into the same housing. 
     The valve insert  110  includes a cylindrical body portion  112 , a cylindrical valve seat  114 , and a piston  116  slideable within the body portion  112 . A biasing member  118 , such as a coiled spring, maintains the piston  116  against the valve seat  114  to form a normally closed seal interface. The seal interface may be metal-to-metal, although other materials may be used as desired. 
     A cap member  120  threadingly engages the housing  102  to enclose a threaded shaft  122 , which extends through a distal end of the cap member  120 . An interior flange  124  presses against the biasing member (spring)  118  to set a desired preload biasing force on the piston  116 . An exterior threaded nut  126  can be used to maintain this preload force. 
     When the pressure of a pressurized fluid at the inlet port  104  reaches a predetermined threshold sufficient to overcome the preload bias force, the piston  116  is axially displaced upwardly as shown in  FIG. 2 , facilitating a flow of the pressurized fluid from the inlet port, through the medial chamber and the insert  110  to the outlet port  106 . When the pressure of the fluid is subsequently reduced, the spring  118  will reseat the piston  116  onto the valve seat  114  and the valve  100  will return to the normally closed position of  FIG. 1 . 
       FIGS. 3A-3B  show respective exploded views of the valve insert  110  of  FIGS. 1-2  in accordance with some embodiments.  FIG. 3A  is an isometric depiction of the insert, and  FIG. 3B  is a cross-sectional depiction of the insert. The relative orientation of the various components can correspond to the direction of assembly of the respective components along a central axis  128 . 
     The body portion  112  has an outer cylindrical surface  130  through which a series of apertures  132  are arranged. Four (4) equally spaced apertures  132  are depicted in  FIGS. 3A-3B , although different numbers and spacings of apertures can be provided. While the apertures are circular in cross-sectional shape, this is merely exemplary as any suitable shape or shapes can be used. 
     The piston  116  includes a piston stem (shaft)  134  at a first end and a piston head  136  with a curvilinearly shaped sealing surface  137  at an opposing second end. The surface  137  is adapted to provide a bubble tight seal against the upper interior corner surface  139  of the valve insert  114 . The respective shapes and material configurations of these surfaces can be adapted desired to effect a seal. 
     A pair of adjacent annular sealing members  138 ,  140 , such as elastomeric o-rings, can be disposed in an annular groove  142  along the piston stem  134 . The sealing members  138 ,  140  form a fluidic seal against an interior annular sidewall  144  of the body portion  112  so that the sealing members  138 ,  140  seal off the interior of the cap member  120  as depicted in  FIGS. 1-2 . Other sealing configurations can be used, including a single o-ring or other forms of sealing members. 
     The cap member  120  is vented using a vent aperture  146  so that the interior of the cap member is continuously maintained at the same pressure as the surrounding external atmosphere. This provides a balanced valve configuration for the valve assembly  100  in  FIGS. 1-2 . In a balanced pressure mode of operation, the valve  100  will open when the upwardly directed inlet pressure upon the exposed piston surface  137  provides a force that overcomes the downwardly directed bias force of the spring  118 . 
     The opening setpoint pressure will be substantially independent of the downstream pressure at outlet port  106 , and will instead be substantially governed by the magnitude of the inlet pressure. More specifically, the opening force F upon the piston  116  will be a function of the pressure P of the inlet fluid and the amount of exposed area A of the piston (F=P·A). Providing a larger or smaller exposed piston area will thus provide different opening forces for the same inlet fluid pressure, and the spring can be empirically set to allow the piston to become unseated when the desired inlet pressure level is reached. 
     The valve assembly can be modified to operate as a differential pressure valve, as depicted at  100 A in  FIG. 4 . The differential pressure valve  100 A is substantially identical to the balanced pressure valve  100 , except that the differential pressure valve  100 A omits the sealing members  138 ,  140  and uses an alternative cap member  120 A without the vent aperture  146  so that the interior of the cap member is hermetically sealed with respect to the surrounding external atmosphere. 
     The differential pressure valve  100 A operates in response to the pressure differential, or relative difference, between the inlet pressure at port  104  and the outlet pressure at port  106 . In a differential pressure mode of operation, the valve  100 A will open when the difference in these pressures is sufficient to provide an upwardly directed force upon the exposed piston surface  137  that overcomes the combined downwardly directed bias force from the spring  118  and the downwardly directed force upon the piston  136  from the downstream pressurized fluid adjacent port  106 . 
     In both the balanced pressure and differential pressure modes of operation, the piston head  136  reciprocates between the closed (sealed) and open (flow) positions within a central chamber of the body portion  112  defined by an annular interior sidewall  148 . A second annular sidewall  150  in the body portion  112  is recessed from the sidewall  148  to form a second chamber with a shoulder surface  151  therebetween. The second chamber accommodates sliding insertion of the cylindrical valve seat  114 . The valve seat  114  is reversible, so that both upper internal corner surface  139  and lower internal corner surface  152  can be alternatively used as a valve seat to form a bubble tight seal, depending on the insertion orientation of the valve seat  114 . 
     The valve insert  110  can be quickly and easily assembled either manually or via automated assembly methods without the need for special tooling or fasteners. With reference again to  FIGS. 3A-3B , during manufacture the piston  116  is slidingly inserted upwardly into the body portion  112 , followed by insertion of the valve seat  114  against the annular sidewall  150 . An annular sealing member  154 , such as an elastomeric o-ring, can be fitted into a gap between the insert  114  and the body portion  112 , as shown in  FIGS. 1-2  and  4 . A second annular sealing member  156 , also preferably characterized as an elastomeric o-ring, can be inserted into an annular groove (channel)  158  in an upper end of the body portion  112 . 
     Once assembled, the valve insert  110  is dropped or otherwise placed into the medial chamber of the valve housing  102 , as generally depicted in  FIG. 5 . The sidewall  108  includes a central annular recessed surface  160  which provides an annular channel  107  to facilitate the flow of fluid through apertures  132  and between the outer surface of the body portion  112  and the inner sidewalls  108 ,  160 . 
     The chamber is larger in diameter than the outermost diameter of the valve insert  110  to accommodate placement of the valve insert  110 . It is not necessary to precisely center the valve insert  110  within the chamber during such placement. 
     Once the insert  110  has been lowered into the chamber  107 , the spring  118  ( FIGS. 1-2  and  4 ) is placed onto the distal end of the piston stem  134 . The threaded shaft  122  with flange  124  attached thereto is threaded upwardly into the cap member  120  through the nut  126  to provide a cap assembly. The cap assembly is lowered onto the housing so that the flange  124  engages the top of the spring  118 . The cap assembly is thereafter rotated to threadingly engage the housing, and the shaft  122  is rotated to set the bias force of the spring  118 . 
     Precise centered placement of the valve insert  110  within the housing  102  is not required during assembly or subsequent operation, so long as the lower sealing member  158  establishes a fluid tight seal against the shoulder surface  151  and sufficient flow space is provided between the interior chamber wall(s) and the outer surface of the body portion  112 . The valve insert  110  can accordingly be located in an offset position with respect to a central axis of the medial chamber of the housing  102 , as generally represented (in exaggerated form) in the schematic depiction of  FIG. 6 . 
     It is contemplated that the valve  100  will operate reliably even if the valve insert is offset somewhat within the chamber, including in an offset position in which the outer annular wall surface of the body  112  is in physical contact with a portion of the interior chamber walls. In some embodiments, the spring  118  and flange  124  may be configured to urge the valve insert  110  to a more centered position during assembly of the completed valve. 
     It has been found that the foregoing valve insert subassembly and top level valve assembly manufacturing steps can be carried out in a matter of a few minutes, if not seconds, and presents a significantly easier and more reliable design over prior art valve assemblies. 
       FIG. 7  illustrates another exemplary valve assembly  200  that uses the valve insert  110  discussed above. Unlike the 90 degree valve assemblies  100 ,  100 A, the valve assembly  200  takes a generally in-line configuration so that the outlet port  106  is extending in the same direction as, and is aligned with, the inlet port  104 . 
     To accommodate the in-line configuration, the fluidic flow from inlet port  104  passes up an angled inlet channel  162  to an interior chamber which accommodates the valve insert  110 . With a sufficient amount of inlet pressure, the piston  116  moves away from the valve seat  114  and fluid flow through the body  112 , down angled outlet channel  164  and out the outlet port  106 . As with the valves  100  and  100 A, the valve  200  can be given a balanced valve or a differential pressure valve configuration through the inclusion or omission of seals  138 ,  140  and vent aperture  146 . 
     It will now be appreciated that the various embodiments presented herein can provide a number of benefits over the prior art. The valve insert can be quickly and easily assembled into a self-contained unit which then can be placed into a number of different housing and cap combinations to provide either pressure differential and balanced valve configurations in both in line and right angle orientations. This allows for standardized manufacturing in that a population of nominally identical valve inserts  110  can be used in a wide variety of different valve models with different configurations. 
     The valve design is highly modular and can be easily serviced with various parts that are replaceable in the field or in post-return processing environments. The use of a reversible annular valve seat such as the exemplary seat  114  provides the opportunity to obtain extended life because the seat  114  can be easily removed, rotated 180 degrees and then reinstalled. Various other elements such as the piston  116  and the sealing o-rings  150 ,  156  can also be readily replaced. 
     An existing valve can be converted between a balanced configuration and a differential pressure configuration by simply adding/removing the sealing members  138 ,  140  and changing the cap  120 . In some embodiments, the valve aperture  146  can be threaded to accommodate the insertion or removal of a threaded plug (not separately shown) depending on whether balanced or differential pressure operation is desired. 
     Different springs (or other biasing members) can be used to provide different biasing force ranges for a given inlet/outlet diameter (e.g, 2½ inch conduits, 4 inch conduits, etc.). Similarly, different valve seats  114  with different interior diameters and the same outer diameters and thicknesses can be provided to accommodate smaller or larger interior cross-sectional flows and amounts of exposed area of the piston surface  137 . 
     It is to be understood that even though numerous characteristics and advantages of various embodiments of the present disclosure have been set forth in the foregoing description, together with details of the structure and function of various embodiments, this detailed description is illustrative only, and changes may be made in detail, especially in matters of structure and arrangements of parts within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. For example, the particular elements may vary depending on the particular application without departing from the spirit and scope of the present technology.