Abstract:
An exercisable check valve having a fluid delivery test channel and piston closure is disclosed herein. A valve closure member stops flow through the valve in the presence of backwards pressure or when engaged by the piston. The valve may be tested by applying a pressure source to the fluid delivery test channel to cause the piston to engage the valve closure member and stop flow through the valve. A test rod may then be inserted into a test rod port to ensure the valve closure member is in the proper closed position. The check valve may also include a biasing element to bias the valve closure member to an open position and a drainage channel. The check valve may be used in any piping or valve system.

Description:
TECHNICAL FIELD 
       [0001]    This invention generally relates to check valves, and more specifically to an exercisable, biased, nozzle-type check valve having a piston assembly. 
       BACKGROUND OF THE INVENTION 
       [0002]    Valves are conventionally used in a number of applications to control the flow of fluids through piping systems. Traditionally in conventional check valves, including flap-type valves, ball valves, disc valves, and the like, the check valve is configured to allow flow in only one direction through the piping system. Such a check valve may allow fluid flow past the valve closure member in one direction while preventing fluid from flowing in the other direction, for example, toward a compressor or pump. In this way, check valves can be used to protect a compressor, pump, or other component from backwards flow or backwards pressure (backpressure). 
         [0003]    In some applications, check valves are biased via a spring or other biasing mechanism. For example, “normally open” valves are biased open, requiring backpressure to close the valve and “normally closed” valves are biased closed, requiring forward pressure to open the valve. When either valve is operating correctly, the valve remains open while fluid is flowing through the valve in a forward direction, from an inlet to an outlet, and if the fluid flow reverses, the valve closes. This prevents flow in an unintended direction. 
         [0004]    For both types of check valves, the valve may be installed in a plant or factory where the valve may not require replacement for the life of the plant or factory. However, to ensure safe operating conditions, there may be a desire to verify the operation of the check valve to ensure that the valve properly prevents backwards flow. Further, there may be regulatory requirements requiring periodic verification of proper operation. However, it is difficult or impractical to test a conventional check valve, since testing will often require either inducing backwards flow in the plant or factory or removing the valve, possibly requiring a significant halt in production. 
         [0005]    Exercisable check valves do exist for which proper operation may be verified by testing. See, for example, U.S. Pat. No. 8,701,693. 
         [0006]    However, there is a desire in the industry to enhance the ability to exercise a check valve to verify proper operation, such that a continuing need exists for a more efficient method and system to quickly and easily test the operation of a check valve without requiring significant additional clean up and without causing significant generation of waste. 
       SUMMARY OF THE INVENTION 
       [0007]    Briefly described, the present disclosure generally describes an exercisable check valve having a piston assembly. According to one embodiment, the check valve of the present disclosure includes a valve body having an inlet, an outlet, and a flow passage between and fluidly connecting the inlet and outlet. The check valve also includes a valve closure member, a piston assembly, and a test fluid delivery channel. According to some embodiments, the check valve also includes a biasing element that causes the check valve to be normally biased open. The valve is suitable for use in any conventional piping system, or the like. 
         [0008]    In the presence of forward flow, the check valve remains open while fluid flows into the inlet, through the flow passage, and out the outlet, such that fluid may flow through the valve and any associated piping system. In the case of reverse flow or backpressure, the reverse flow or backpressure will cause the valve closure member to engage the valve body to interrupt flow through the check valve. In this way, the check valve only allows flow in one direction. 
         [0009]    The piston assembly is used to drive the valve closure member during testing of the valve and includes a piston bore received in a support member within the flow passage and a piston at least partially received in the piston bore. A test fluid delivery channel fluidly connects the exterior of the valve body to the piston bore. To verify proper operation of the check valve, a user applies a source of pressure to the test fluid delivery channel. Application of pressure will cause the piston to move relative to the piston bore, driving the valve closure member and causing the valve closure member to engage the valve body to interrupt fluid flow through the flow passage. A rod may then be inserted through a port in the valve to determine whether the closure member is in the proper closed position. In this way, the valve may be exercised and tested without being removed from a piping system, without inducing significant backwards flow through the piping system, and without significant clean-up. 
         [0010]    Various objects, features, and other advantages of the present invention will become apparent to those skilled in the art upon a review of the following detailed description when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a cross-sectional profile view of an exemplary check valve in an open configuration, according to a first embodiment of this disclosure. 
           [0012]      FIG. 2  is a cross-sectional profile view of an exemplary check valve in a closed configuration, according to a first embodiment of this disclosure. 
           [0013]      FIG. 3  is a perspective view of an exemplary check valve according to a first embodiment of this disclosure. 
           [0014]      FIG. 4  is a perspective view of an exemplary check valve with a section of the valve body cut away, in a closed configuration, according to a first embodiment of this disclosure. 
           [0015]      FIG. 5  is an end view of an exemplary check valve according to a first embodiment of this disclosure from a perspective taken looking directly into the inlet. 
           [0016]      FIG. 6  is an end view of an exemplary check valve according to a first embodiment of this disclosure from a perspective taken looking directly into the outlet. 
           [0017]      FIG. 7 a    is a cross-sectional perspective view of an exemplary check valve in an open configuration, according to a first embodiment of this disclosure. 
           [0018]      FIG. 7 b    is a cross-sectional perspective view of an exemplary check valve in a closed configuration, according to a first embodiment of this disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    Referring now in greater detail to the drawings in which like numerals refer to like parts throughout the several views,  FIGS. 1 and 2  respectively illustrate one embodiment of an exercisable check valve  10  according to the present disclosure in an open and a closed configuration. However, it will be understood by those skilled in the art that the check valve disclosed herein is suitable for use with any type of piping or tubing system, or the like, including in the piping system of a factory or plant, such as a power plant. The present disclosure thus is not and should not be limited solely for use with a particular type or types of piping or flow delivery system. 
         [0020]    Although the following description includes an exemplary check valve and methods that embody the inventive subject matter of this disclosure, it will be understood by a person of ordinary skill in the art that the described subject matter may be practiced with some or all features of the embodiments disclosed herein in various combinations to create various other embodiments not expressly disclosed herein but nonetheless within the scope of this disclosure. 
         [0021]      FIG. 1  is a cross-sectional view of a check valve  10  in an open configuration according to an embodiment of the present disclosure. The check valve  10  includes a valve body  20  having an inlet  22 , an outlet  24 , a flow passage  28  between and fluidly connecting the inlet  22  and outlet  24 , and a piston assembly  30 . The valve  10  is configured to allow flow into the inlet  22 , through the flow passage  28 , and out from the outlet  24 , and to prevent flow of fluid in the reverse direction, i.e. from the outlet  24  to the inlet  22 . 
         [0022]    According to the embodiment shown in  FIGS. 1 and 2 , the piston assembly  30  includes a piston bore  32  and a piston  36  at least partially received in the piston bore  32 . The piston bore  32  is formed in a downstream support member  42 , and the downstream support member  42  is fixed relative to the valve body  20 . 
         [0023]    Still according to the embodiment shown in  FIGS. 1 and 2 , a valve closure member  50  is received in the flow passage  28 . The valve closure member  50  is supported in such a way as to be movable between at least an open position in which fluid may flow through the flow passage  28  and a closed position in which the valve closure member  50  cooperates with the valve body  20  (by, for example, sealing at a valve closure seat  26 ) to interrupt fluid flow through the flow passage  28 . The valve closure member  50  is engaged by the piston  36  such that the piston  36  acts to move the valve closure member  50  to the closed position when the piston  36  is moved from a first position to a second position. 
         [0024]    According to some embodiments, the piston  36  and valve closure member  50  are coupled so that movement of the piston  36  to and from the first and second positions causes respective movement of the valve closure member  50  to and from the open and closed positions. In some such embodiments, a biasing element  60  is coupled to either the piston  36  or the valve closure mechanism  50  to respectively bias either the piston  36  to its first position or the valve closure member  50  to its open position. 
         [0025]      FIG. 2  depicts a cross-sectional view of a check valve  10  in the closed configuration according to some embodiments. The presence of backwards flow or pressure in the direction from the outlet  24  to the inlet  22  causes the valve closure member  50  to move to the closed position. In the closed position, the valve closure member  50  engages the valve closure seat  26 , thus cooperating with the valve body  20  to block fluid flow through the flow passage  28  from the outlet  24  to the inlet  22 . This feature is particularly desirable in situations where equipment which could become damaged from reverse flow, such as a pump or compressor, is located upstream from the check valve  10 . Further, this feature of preventing reverse flow may be required for compliance with safety regulations. 
         [0026]    A fluid delivery test channel  70  fluidly connects the interior of the piston bore  32  with the exterior of the valve body  20 . Application of fluid or another pressure source to the fluid delivery test channel  70  causes the piston  36  to move from the first position to the second position which in turn causes the valve closure member  50  to move to the closed position. In this way, the fluid delivery test channel  70  can be used to cause the valve closure member  50  to be in the closed position. 
         [0027]    The check valve  10  according to some embodiments further includes additional ports  80 ,  90  that fluidly connect the exterior of the valve body with the interior of the flow passage. These ports are configured to support inspections as will be understood by those of ordinary skill in the art. 
         [0028]    With reference to  FIGS. 1 and 2 , operation of the fluid delivery test channel  70  and piston assembly  30  will now be described according to some embodiments. As previously mentioned, the piston bore  32  is located within the downstream support member  42  and the piston  36  is at least partially received within the piston bore  32 . According the embodiment shown in  FIGS. 1 and 2 , the fluid delivery test channel  70  extends from a fluid delivery test channel opening  72  in the valve body, to another fluid delivery test channel opening  74  in the rear portion  34  of the piston bore  32 . To test the operation of the valve and to ensure its ability to properly prevent flow in the reverse direction (i.e. from outlet  24  to inlet  22 ), a source of pressurized fluid (e.g. a liquid), is connected to the valve body fluid delivery test channel opening  72 , and the pressurized fluid is introduced through the test channel  70 . 
         [0029]    The piston assembly  30  (including piston  36  and piston bore  32 ) is configured in a manner as will be understood by those skilled in the art such that the pressure source causes pressure to build up behind the piston  36  in the rear portion  34  of the piston bore  32 , causing a force to act on the piston end  46  sufficient to move the piston  36  from the first position to the second position, in turn causing the valve closure member  50  to move to the closed position. 
         [0030]    According to the embodiment of  FIGS. 1 and 2 , the biasing element  60  is a spring  60  mounted on the upstream side of the closure member  50  and supported as to assert pressure against the closure member  50  for normally biasing the valve closure member  50  to its open position. According to some embodiments, the biasing element  60  is supported on an upstream end by an upstream support member  44  that is fixed relative to the valve body  20 , and the biasing element  60  exerts pressure against the closure member  50  and the upstream support member  44  to bias the closure member  50  to the open position. 
         [0031]    As previously described, in some embodiments, such as shown in  FIGS. 1 and 2 , the piston  36  and valve closure member  50  are coupled such that when the piston  36  is in the first position, the valve closure member  50  is in the open position and when the piston  36  is in the second position, the valve closure member  50  is in the closed position. In such embodiments where the piston  36  and valve closure member  50  are coupled, it is only necessary to bias one of the valve closure member  50  and the piston  36 , since the other will be biased as a result of the piston  36  and valve closure member  50  being coupled. 
         [0032]    According to the embodiment of  FIGS. 1 and 2 , the coupling is in the form of rigid attachment, such as welding or forging as one component. Other forms of coupling are also acceptable, such as but not limited to hinging, linking, or the like. 
         [0033]    As understood in the art, the piston  36  is configured such that a small amount of pressure in the piston bore  32  is sufficient to overcome the biasing force of the biasing element  60  to cause the piston  36  to move from the first position to the second position. It will be appreciated that the piston bore  32 , piston  36 , and biasing element  60  may be calibrated such that a predetermined amount of pressure is sufficient to overcome the biasing force of the biasing element  60 . In this way, a user may calibrate the sensitivity of the check valve to backwards flow and/or test conditions. 
         [0034]    Referring again to  FIGS. 1 and 2 , the biasing member  60  is a compression spring. The compression spring is calibrated such that the presence of a predetermined amount of backwards flow or backwards pressure will cause the valve closure member  50  to overcome the spring force and move to the closed position. 
         [0035]    The valve closure member  50  of the embodiment of  FIGS. 1 and 2  is in the nature of a valve closure disc  50 . The piston  36  and valve closure disc  50  are components of a valve closure disc assembly  40  that further includes an upstream shaft portion  38  rigidly mounted to the disc  50  and axially aligned with and on the opposite side of the disc  50  from the piston  36 . The upstream support member  44  is mounted inside the flow passage  26 . The valve closure disc assembly  40  is slidably supported by and movable relative to the upstream support member  44 , and the biasing member  60  is also coupled to the upstream support member  44 . 
         [0036]    The valve closure disc assembly  40  further includes first shaft end  46  (defined as the free end of the piston (or downstream shaft portion)  36 ), which extends into and terminates within said piston bore  32 , and a second shaft end  48  (defined as the free end of the upstream shaft portion  38 ) which extends into and terminates within said flow passage  28 . The valve closure disc  50  is coupled to the piston  36  between the first and second shaft ends  46 ,  48 . According to some embodiments, the first shaft end  46  is the downstream end of the piston  36  (i.e. the end closer to the outlet  24 ), and the second shaft end  48  is the upstream end of the piston (i.e. the end closer to the inlet  22 ). 
         [0037]    According to some embodiments, the valve closure disc  50  has a first valve closure disc face  52  facing the outlet  24  and a second valve closure disc face  54  facing the inlet  22 . In such embodiments, the presence of backwards flow or backwards pressure causes a force to be applied to the first disc face  52 . When sufficient force on the first disc face  52  is present, the disc will be moved to the closed position in which the second face  54  of the disc  50  will mate with the valve closure disc seat  26  to interrupt flow through the flow passage  28 . According to some embodiments, the upstream support member  44  is positioned between the valve closure disc  50  and the second shaft end  48 . 
         [0038]    It will be understood by those skilled in the art that while the present invention has been disclosed with reference to specific embodiments as described, above, various additional, deletions, modifications and changes can be made thereto without departing from the spirit and scope of the present invention. It will also be understood that the various embodiments and/or features thereof can be combined to form additional embodiments of the present invention.