Abstract:
A normally open flow control valve includes a housing having an inlet port, an outlet port and an interior passageway with a valve seat. A moveable valve member has a sealing head supported for rotation by a cantilevered arm. The sealing head has a sealing member adapted to establish a fluidic seal against the valve seat in a closed position. A biasing member applies a biasing force to the valve member to bring a contact surface of the valve member into contacting engagement with a distal end of a projection pin in an open position. When a flow rate of a pressurized fluid at the inlet port exceeds a selected threshold, impingement of the pressurized fluid against the sealing head rotates the valve member from the open position to the closed position.

Description:
RELATED APPLICATIONS 
       [0001]    This application makes a claim of domestic priority to U.S. Provisional Patent Application No. 61/970,029 filed Mar. 25, 2014, the contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    Pressurized fluid systems are often used to transport and direct a pressurized fluid 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 
       [0003]    Various embodiments of the present disclosure are generally directed to an apparatus that provides emergency shutdown of a fluidic flow in response to an increase in a flow rate of the fluid. 
         [0004]    In some embodiments, a normally open flow control valve includes a housing having an inlet port, an outlet port and an interior passageway therebetween. A valve seat is disposed within the interior passageway. A valve member disposed within the interior passageway has a sealing head supported for rotation by a cantilevered arm, the sealing head having a sealing member adapted to establish a fluidic seal against the valve seat in a closed position. A projection pin extends into the interior fluidic passage way, and a biasing member applies a biasing force to the valve member to bring a contact surface of the valve member into contacting engagement with a distal end of the projection pin in an open position. When a flow rate of a pressurized fluid at the inlet port exceeds a selected threshold, impingement of the pressurized fluid against the sealing head rotates the valve member to the closed position. 
         [0005]    These and other features and advantages of various embodiments will become apparent by a review of the following detailed description and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0006]      FIG. 1  is a functional block representation of a transformer coolant system to provide an exemplary environment for various embodiments of the present disclosure. 
           [0007]      FIG. 2  is a perspective view of a flow control shutdown valve suitable for use in the system of  FIG. 1 . 
           [0008]      FIG. 3  is a side cross-sectional view of the valve of  FIG. 2  in a normally open position with a rotatable valve member of the valve in a first initial rotational position (angle). 
           [0009]      FIG. 4  shows the valve of  FIG. 3  with the rotatable valve member rotated to a closed position. 
           [0010]      FIG. 5  depicts a valve adjustment mechanism of the valve with the rotatable valve member in a second initial rotational position (angle). 
           [0011]      FIG. 6  is an end cross-sectional view of the valve of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Without limitation, various embodiments of the present disclosure are generally directed to a flow control shutdown valve. As explained below, in at least some embodiments the valve is adapted for use in a pressurized fluid piping network to provide emergency shutdown operation in response to an increase in the flow of the transported fluid. The valve can be used in any number of different operational environments, such as an exemplary transformer cooling system  100  depicted in  FIG. 1 . 
         [0013]    The system  100  includes a recirculating pump  102 , a flow control shutdown valve  104 , a heat exchanger  106  and a coolant reservoir  108 . Other elements can be incorporated into the system  100  as desired. A suitable coolant fluid such as oil or a glycol-water mixture is circulated through suitable conduit pipes (generally denoted at  110 ) to remove waste heat from a heat load, such as one or more power transformers (not separately shown). 
         [0014]    While any number of pressure ranges can be used, it is contemplated in some embodiments that the pump  102  will establish a relatively low pressure of the fluid as it circulates, such as on the order of about 12 pounds per square inch (psi). Other pressure ranges can be used and the valve is not necessarily limited to such relatively low pressures. In one embodiment, the normal pressure of the pressurized fluid is in a range of from about 2 pounds per square inch (psi) to about 25 psi. The conduit pipes  110  are sized to accommodate the desired flow rate, and may be on the order of about two inches in diameter (2 in. ID) or some other value. 
         [0015]    As will be recognized, the flow rate of a fluid, also referred to as the volumetric flow rate Q, represents the volume of fluid which passes a given point in the system per unit of time. Q may be expressed as cubic feet per second (ft 3 /s), gallons per minute (gal/min), cubic centimeters per second (cc 3 /s), etc. Albeit related, flow rate Q is distinct from the pressure P of a fluid. 
         [0016]    Pressure is generally represented as a force of the fluid acting per unit area and may be expressed as pounds per square inch (lbs/in 2  or psi), newtons per square meter (N/m 2  or pascals, Pa), etc. A difference in pressure may induce flow, but the volume of the flow will be governed by other state variables such as cross-sectional area available to the fluid, etc. The significance of this distinction between flow rate and pressure will be apparent below. 
         [0017]      FIG. 2  is a perspective view of a flow control shutdown valve  120  suitable for use in the system  100  of  FIG. 1  to provide emergency shutdown operation in the event of an increase in fluidic flow (increased Q) of the coolant fluid. The reason for an increase in fluidic flow is not necessarily germane to the present discussion since a number of factors can arise that would result in an increased flow depending upon the operational environment. 
         [0018]    In one example, damage incurred to the system  100  of  FIG. 1 , such as through a leak or break in the conduits  110  downstream from the valve  120 , could result in an increase in fluidic flow due to an increased system pressure differential across the valve. It is presumed that other suitable shutdown protocols are in place to address the resulting shutoff of the cooling fluid by the valve  120 , such as by deactivation of the load, bypass and/or shutdown of the pump, etc. 
         [0019]    Interior aspects of the valve  120  will be discussed below, but at this point it can be seen that the valve includes a rigid in-line housing  122  with opposing inlet and outlet flanges  124 ,  126 . The housing and flanges may be formed as an integral piece of any suitable material including metal, plastic, etc. In some cases, the housing and flanges are formed of ABS plastic (acrylonitrile butadiene styrene) or PVC (polyvinyl chloride) using an injection molding operation. 
         [0020]    The inlet and outlet flanges  124 ,  126  are adapted to be connected to corresponding couplings of the conduit pipes  110  ( FIG. 1 ) using threaded fasteners (not shown) that extend through spaced apart apertures  128 . An inlet port (not visible in  FIG. 2 ) extends through the inlet flange  124  to provide ingress of the fluidic flow. An outlet port  130  extends through the outlet flange  126  to provide egress of the fluidic flow. The flanges  124 ,  126  are optional. 
         [0021]    The valve  120  as configured in  FIG. 2  is an in-line valve so that the inlet and outlet ports are axially aligned, although the housing  122  can take any suitable shape, including non-inline configurations, as required. For example, in an alternative embodiment the outlet port is arranged at nominally  90  degrees with respect to the inlet port. 
         [0022]    A cover plate  132  is affixed to an upper portion of the housing  122  via an array of threaded fasteners  134 . The cover plate  132  includes a central boss projection  136  into which a valve adjustment mechanism extends. A user operated, spring-loaded reset handle  138  extends from a side of the housing  122 . Both the valve adjustment mechanism and the handle will be discussed in greater detail below. 
         [0023]      FIG. 3  shows a cross-sectional depiction of the valve  120  of  FIG. 2  in accordance with some embodiments. The valve  120  is reversed as compared to the view in  FIG. 2 , so the inlet flange  124  and aforementioned inlet port  140  are located on the right-hand side of  FIG. 3 , and the outlet flange  126  and outlet port  130  are located on the left-hand side of  FIG. 3 . The handle  138  from  FIG. 2  is behind the housing  122  and hence, not visible in  FIG. 3 . 
         [0024]    An interior fluidic passageway  142  is formed within the housing  122  between the inlet and outlet ports. Disposed within the passageway  142  is a flapper-type valve member  150 . The valve member  150  is in a normally open position as shown in  FIG. 3  to allow the coolant fluid to flow through the housing. 
         [0025]    The valve member includes a sealing head  152  with an annular sealing member  154 . The sealing head  152  can be formed of a single piece or multiple assembled pieces, as shown. The sealing head  152  is supported by a cantilevered arm  156 . The arm  156  is affixed for rotation about a central axis that passes through a transverse shaft  158  affixed to the handle  138  ( FIG. 2 ). A retention fastener  160  extends through the arm  156  and shaft  158  so that these members, along with the sealing head  152 , rotate as a unit. It is contemplated that the sealing head  152  will remain fixed in relation to the arm  156 , but in other embodiments the sealing head may be permitted to axially rotate relative to the arm. 
         [0026]    Inlet fluid impinges against an outer surface  164  of the sealing head  152 . A biasing member (not shown in  FIG. 3 ), such as a coiled spring, applies a biasing force that urges the valve member  150  to the open position as shown in  FIG. 3 . 
         [0027]    During normal operation, the circulating coolant fluid will flow through the housing  122  from the inlet port  140  to the outlet port  130 . At such time that the magnitude of the flow provides a force upon the outer surface  164  of the sealing head  152  that overcomes the biasing force supplied by the biasing member, the valve member  150  will rotate about the central axis of the shaft  158  and transition to a closed position, as generally depicted in  FIG. 4 . 
         [0028]    In the closed position, the sealing member  154  of the sealing head  152  establishes a fluidic seal against a valve seat surface  166  to impede further flow of the fluid through the housing  122 . Depending on the rate of flow of the coolant fluid, in some cases the valve member  150  may only partially close as the fluid urges the sealing head  152  toward the valve seat surface  166 , thereby restricting the cross-sectional area of the interior flow passageway  142  available for use by the fluid as the fluid flows through the housing. In other cases, the rate of flow of the fluid will be sufficient to fully seat the sealing head  152  against the valve seat surface  166  and shut off further flow through the valve  120 . In this way, the valve  120  operates to regulate the volumetric flow rate of the fluid through the system  100 . 
         [0029]    Returning again to  FIG. 3 , a valve adjustment mechanism is generally denoted at  170 . The valve adjustment mechanism  170  generally comprises a threaded projection pin  172  which extends through a threaded aperture in the cover plate  132  and into the interior flow passageway  142 . The projection pin  172  includes a head  174  with an interior hex driving surface  176  to permit a user activated driver tool (not shown) to rotatably advance or retract a distal end  178  of the pin  172  within the housing. This changes the relative location of the distal end  178  of the pin  172 . 
         [0030]    Threads (not separately shown) extend along the length of the pin  172  from the head  174  to the distal end  178 . These threads engage corresponding threads in the cover plate  132  (not separately shown) to facilitate the advancement and retraction of the pin  172 . A shorter run of threads along an appropriate operative area of the pin can be provided as desired. 
         [0031]    The distal end  178  of the pin  172  serves as a limit stop to set the initial angular orientation of the valve member  150  through contact between the distal end  178  of the pin  172  and a limit surface  179  of the cantilevered arm  156 . A relatively higher initial location of the distal end  178  will place the sealing head  152  at a first rotational position (angle) that is higher up and more out of the way of the inlet fluid flow, as generally depicted in  FIG. 5 . Lowering the distal end  178  of the pin  172  will place the sealing head at a lower second rotational position (angle) that is more in the way of the inlet fluid flow, as depicted in  FIG. 3 . 
         [0032]    By threadingly advancing or retracting the pin  172 , the pin can be easily raised or lowered to adjust the valve member  150  to any suitable rotational position over a continuous range of available positions. The available positions range from a fully open position (at which a significant increase in fluidic flow is required to close the valve) to a position that is almost closed (so that a relatively small increase in fluidic flow is sufficient to close the valve). It follows that a greater amount of fluid flow will be required to transition the valve to the closed position if the valve is configured at the first rotational position shown in  FIG. 5  as compared to the second rotational position in  FIG. 3 , due to the different locations and presentation angles of the sealing head  152 . 
         [0033]    By setting the initial rotational position of the valve member  150 , a series of setpoint flow rate thresholds can be established responsive to the biasing force of the spring and the angle of the valve member. An increase in the flow rate above a first threshold level will initiate partial advancement of the valve member  150  toward the valve seat surface  166 , thereby restricting the volumetric flow of the fluid exiting the valve  120 . 
         [0034]    As the inlet flow rate continues to increase to above a second threshold level, the valve member  150  will fully seat against the valve seat surface  166 , thereby shutting off further flow (e.g., restricting the flow to zero). It will be noted that because the valve  120  operates responsive to changes in fluidic flow, the inlet pressure may remain nominally at a normal system level as the valve transitions to the closed position. 
         [0035]    The head  174  of the pin  172  rotationally advances within a chamber  180  of the cover plate  132 , and a fluidic seal is established between the head  174  and an annular sidewall  182  of the cover plate  132  using a sealing member (o-ring)  184 . A lower annular shoulder surface  186  of the head  174  provides a lower limit surface for the location of the distal end  178  of the pin  172 . An upper limit surface (not separately shown) may be additionally supplied to ensure the sealing member  184  remains in contact with the sidewall  182 . For example, a retention mechanism, such as a threaded nut, may be applied to the pin  172  to prevent the head  174  from being retracted far enough out of the chamber  180  that the fluidic seal between  182 ,  184  is released. 
         [0036]      FIG. 6  shows another cross-sectional view of the valve  120 . The view in  FIG. 6  is generally in a direction from the outlet port  130  toward the valve member  150 . The aforementioned shaft  158  coupled to the valve member  150  extends through a boss projection  190  of the housing to the handle  138  ( FIG. 2 ). A coiled spring  192  includes a number of coils that extend around the boss projection  190  and respectively engage the handle  138  and the housing  122 . In this way, the valve member  150  is normally biased against the distal end  178  of the pin  172  (see e.g.,  FIGS. 3 ,  5 ). 
         [0037]    The handle  138 , shaft  158  and spring  192  thus form a reset assembly that enables a user to reset the valve  120  to the open position in the presence of fluidic pressure and/or flow at the inlet port  140 . The user can rotate the handle to reset the valve member  150  to the open position (see  FIG. 3 ), and the spring  192  will thereafter retain the valve member in this position. However, the use of a handle such as  138  is optional as other mechanisms can be used to reset the valve  120 . The handle  138  serves as a ready visual indicator of the position of the valve (e.g., open or closed). 
         [0038]    A weather cover (not shown) can be incorporated to enclose or otherwise protect the exposed spring from the accumulation of ice or other effects that might tend to impede the operation of the spring. In another embodiment, the spring is located within the housing  122 . 
         [0039]    It is contemplated albeit not necessarily required that the spring will have sufficient force to return the valve member  150  to the open position (e.g., seated against pin  172 ) in the absence of pressure or fluidic flow. If some pressure is present, however, user intervention may be required, via the handle, to return the valve to the open position. Other mechanisms such as automated retractors, actuators, motors, solenoids, etc. may be configured to rotate the valve member to the open position during a reset operation. Other biasing members apart from a coiled spring, such as a counterweight, a membrane, other energy storage mechanisms, magnets, etc., can similarly be used to apply the biasing force to the open position. 
         [0040]    While various embodiments have been generally directed to a flow control valve for a cooling system application, such is merely illustrative and not limiting. Aspects of the various embodiments presented herein can be adapted for use in any number of suitable environments in which a pressurized fluid is passed through a system.