Patent Abstract:
A replaceable valve seat ring for a valve assembly has an annular ring body and an open flow passage extending through the ring body. A seating surface is provided on the ring body adjacent one end of the flow passage. A tool accepting region of the flow passage is formed concentric with and at least partially along the flow passage. The tool accepting region is adapted to receive a standard tool head therein for installing and removing the valve seat ring.

Full Description:
RELATED APPLICATION DATA  
       [0001]    This patent is related to co-pending U.S. Provisional Patent Application Serial No. 60/335,994, which was filed on Nov. 15, 2001. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention generally relates to valves, and more particularly to a replaceable valve seat ring for fluid flow valves.  
         BACKGROUND OF THE INVENTION  
         [0003]    Fluid valves are used in a wide range of fluid process and control system applications for controlling various flow parameters of a process fluid. A wide variety of valve types are known and can include, for example, dump valves, control valves, throttling valves, and the like. Similarly, fluid process and control systems are utilized for handling a myriad of different fluid media.  
           [0004]    A typical valve has a fluid inlet coupled through a flow control or orifice region to a fluid outlet. A closure device of some kind is typically provided in the flow control region with a portion that is movable to control fluid flow from the valve inlet to the valve outlet. The movable portion is often a valve plug that can be moved to bear against a corresponding fixed seating surface of the closure device to selectively shut off flow of fluid through the valve. During continued use of such a valve, the seating surface of the closure device inevitably becomes worn or damaged. Inadequate flow shut off of the closure device will result, causing poor performance or failure of the valve. Thus, the valve seating surface must eventually be repaired or replaced, or the entire valve must be replaced to again achieve proper function of the valve.  
           [0005]    In one known example, a valve seat ring has a seating surface and is disposed within a flow control or orifice region of the valve. The seat ring is removable in order to replace the seat ring or to repair the seating surface. This type of removable seat ring has a hex-shaped head extending upward from a top surface of the ring. The hex head is adapted to accept a particular standard size hex socket or wrench for installing or removing the ring. However, the upwardly protruding hex head negatively interferes with fluid flow through the orifice region of the valve, and the technician must have the particular tool size on hand.  
           [0006]    In another known example, a pair of small blind bores formed into the top surface of the seat ring. These bores are adapted to receive two spaced apart prongs of a specialized tool to install or remove the ring. The technician must have access to this specialized tool at all times in order to service this type of valve. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    Objects, features, and advantages of the present invention will become apparent upon reading the following description in conjunction with the drawing figures, in which:  
         [0008]    [0008]FIG. 1 is a cross sectional view of one example of a dump valve having a replaceable valve seat ring constructed in accordance with the teachings of the present invention.  
         [0009]    [0009]FIG. 2 is a perspective view of the seat ring of the dump valve shown in FIG. 1  
         [0010]    [0010]FIG. 3 is a top view of the seat ring shown in FIG. 2.  
         [0011]    [0011]FIG. 4 is a side cross sectional view taken along line IV-IV of the seat ring shown in FIG. 3.  
         [0012]    [0012]FIG. 5 is a side cross sectional view taken along line V-V of the seat ring shown in FIG. 3.  
         [0013]    [0013]FIG. 6 is a side cross sectional view of the seat ring as shown in FIG. 4 and having a standard extension of a socket wrench installed in the seat ring for installation or removal from the dump valve shown in FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0014]    A valve seat ring for a fluid valve or the like is disclosed herein that is easily installed, removed, and replaced utilizing conventional hand tools. The disclosed valve seat ring is suitable for many different types of valves. The example set forth herein is described with reference to what is known as a sliding stem type “dump” valve construction. However, the disclosed seat ring is equally well suited for many other types and constructions of valves, such as, for example, control valves, throttling valves, or the like. The present disclosure is not to be limited to any particular type of valve.  
         [0015]    The disclosed seat ring includes a region for accepting a standard size and shape socket wrench extension. The standard socket wrench can be utilized to remove and install a seat ring in the valve as desired. The valve seat ring also provides smooth flow characteristics in conjunction with the tool accepting region.  
         [0016]    Referring now to the drawings, FIG. 1 shows one example in cross section of a sliding stem type dump valve  10  constructed in accordance with the teachings of the present invention. The dump valve  10  has a valve body  12  with a fluid inlet  14  at one end and a fluid outlet  16  at an opposite end. The fluid inlet is in communication with an inlet passageway  18  and the fluid outlet is in communication with an outlet passageway  20 . Each of the inlet and outlet passageways  18  and  20 , respectively, meet generally within the valve body  12  and are in communication with one another through an orifice region  22 .  
         [0017]    The valve  10  has a valve plug  24  coupled to a valve stem  26  at one end. The valve stem  26  is coupled at its opposite end to an actuator (not shown) that can move the valve stem and plug along a longitudinal axis of the stem.  
         [0018]    The valve plug  24  has a seating surface  28  which comes in contact with and bears against a valve seat ring  30  when in a valve closed position. The valve seat ring  30  is installed in the orifice region  22  as is described in greater detail below. During operation of the dump valve  10 , the actuator (not shown) moves the valve stem  26  and valve plug  24  toward and away from a seating surface  32  of the seat ring  30  to close and open, respectively, the dump valve to permit fluid flow from the inlet  14  to the outlet  16  through the passageways.  
         [0019]    In accordance with the teachings of the present invention, the seat ring  30  disclosed in FIG. 1 is removably installed within the orifice region  22  of the valve body  12 . The orifice region  22  has a bore  34  extending between the inlet passageway  18  and the outlet passageway  20 . The bore  34  has female mechanical threads  36  formed axially along and circumferentially around at least a portion of the bore.  
         [0020]    As shown in FIGS.  2 - 5 , the seat ring  30  has a circular cylindrical perimeter or circumferential surface  38  with male threads  40  that correspond to the female threads  36  of the bore  34 . As shown in FIG. 1, the seat ring  30  as installed is threaded into the bore  34 . By rotating the seat ring  30  in one direction relative to the bore  34 , the ring can be installed in the orifice region  22 . By rotating the seat ring in the opposite direction relative to the bore  34 , the seat ring  30  can be removed and replaced.  
         [0021]    As shown in FIGS. 2 and 3, the seat ring  30  defines a flow orifice  42  through the orifice region  22  when installed. Fluid passes through the orifice  42  of the seat ring  30  when the valve plug  24  is in the valve open position spaced from the seating surface  32  of the ring  30 . The disclosed flow orifice  42  of the ring  30  is a circular orifice, although the shape of the orifice can vary according to the needs of a particular valve design and to achieve desired flow characteristics. An inlet end of the orifice  42  corresponds with the seating surface  32  of the ring  30 .  
         [0022]    Further details of the disclosed seat ring  30  constructed in accordance with the teachings of the present invention are described with reference to FIGS.  3 - 5 . The larger diameter portion of the perimeter surface  38  of the seat ring  30 , including the male mechanical threads  40 , is formed as a circular cylinder. The seat ring  30  also has a smaller diameter, necked-down end  44  adjacent the outlet end of the orifice  42 . The necked-down end  44  is received in a corresponding smaller diameter portion  45  of the bore  34  when installed. The purpose of the necked-down end  44  is to properly position the seat ring  30  in the orifice region  22  and to align the seat ring with the smaller diameter portion  45  of the bore  34 . An annular shoulder surface  46  extends between and connects the necked-down end  44  and the perimeter threaded surface  38  of the ring. When installed as shown in FIG. 1, the shoulder surface  46  of the ring  30  bottoms against a corresponding ledge or stop surface  48  within the bore  34 . The shoulder surface seats against the ledge surface to precisely position the installed seat ring  30  in the bore  34  of the valve body  12 .  
         [0023]    Though mechanical threads are disclosed herein as a mechanical engaging device for installing the valve seat, other mechanical means for securing the valve seat in place can also be utilized. For example, a key and way system can also be used where the seat and a part of the orifice region engage with one another by a twist-and-lock motion. Other alternative constructions are also certainly within the spirit and scope of the invention.  
         [0024]    As best illustrated in FIGS. 4 and 5, the flow orifice  42  in this example extends only part way through the thickness or height of the ring  30 . The inlet end of the orifice  42  opens into and communicates with a larger sized tool receptacle or recess  50 . The tool recess  50  is formed into a top surface  52  of the ring to a desired depth. The tool recess  50  in this example terminates at an intermediate surface  54  within the body of the ring  30 . The intermediate surface generally lies in the plane of the inlet end of the flow orifice  42 . The seating surface  32  is formed as a recessed annular surface in the intermediate surface and surrounds the inlet end of the flow orifice  42 .  
         [0025]    In the disclosed example, the tool recess or accepting region  50  is an essentially square opening having four sides  56   a ,  56   b ,  56   c , and  56   d . The four sides are generally vertically oriented, although the sides can be slightly tapered at a draft angle for casting or forming purposes. In this example, the four sides  56   a - 56   d  and the intermediate surface  54  together define the tool recess  50  having a shape that corresponds to a standard socket wrench extension. In one example, a standard three-quarter inch socket extension can be inserted directly into the tool recess for removing or installing the seat ring  30  (see FIG. 6 and the description below). In other examples, the tool recess  50  can be configured to accommodate different sized socket extensions such as a standard half-inch or three-eighths inch extension size. In still other examples, the tool recess  50  can be configured to accommodate a different standard configuration tool head other than a socket extension, such as a TORX head, ALLEN wrench, hex head, or other standard configuration.  
         [0026]    Because the disclosed seat ring  30  requires only a standard socket extension, the seat ring eliminates the need for purchasing, maintaining, and storing a special tool or a particular sized tool for installing or removing the ring. Instead, only a standard socket extension, common to nearly every technician&#39;s tool box, is sufficient for installation and removal of the valve seat ring. FIG. 6 illustrates a a standard socket extension  58  including an extension head  60  received in the tool recess  50  of the seat ring  30 .  
         [0027]    Aside from the improved installation and removal aspects of the valve seat ring  30 , the ring also provides substantially improved, smooth fluid flow characteristics. For example, the tool recess  50  only extends part way into the valve seat ring  30  and includes no part or element that protrudes upward from the ring top surface or inward into the flow orifice  42 . This seat ring design is thus a substantial improvement over many prior designs which have a protruding feature adapted for accepting a particular tool configuration, as described above.  
         [0028]    The disclosed seat ring  30  provides improved, smooth fluid flow characteristics for additional reasons as well. As shown in FIGS. 4 and 5, the flow orifice  42  is tapered slightly radially outward moving from the inlet end to the outlet end. The radial outward taper of the orifice  42  can achieve certain flow characteristics through the orifice and can be varied, eliminated, or otherwise altered in order to achieve particular desired flow characteristics. Other alternative flow orifice size, and shape configurations are also within the scope and spirit of the present invention. As one example, the separate and discrete flow orifice  42  can be eliminated and the tool recess  50  can extend the entire depth of the seat ring  30  and act as a full length flow orifice. However, in such an example, the valve plug and tool recess must be configured so as to ensure proper seating of the plug to the valve seat to achieve flow shut off. The contours of the tool recess in such an example can be suitably smooth and gradual so as not to severely affect flow characteristics through the recess.  
         [0029]    In the disclosed example, as best illustrated in FIGS. 4 and 5, the top surface  52  of the seat ring  30  is tapered slightly downward moving from near the perimeter surface  38  toward the sides  56   a - 56   d  of the tool recess  50 . The top surface transitions to the side surfaces  56   a - 56   d  of the recess at smooth, rounded edges or surfaces  62 . The side surfaces  56   a - 56   d  again smoothly transition at smooth, rounded interior bottom corners  64  into the intermediate surface  54 . The sides  56   a - 56   d  also transition laterally into one another at smooth, rounded corners  66 . The intermediate surface  54  is also angled or tapered slightly downward moving from the tool recess sides  56   a - 56   d  toward the seating surface  32  at the inlet end of the flow orifice  42 . The intermediate surface  54  and the seating surface  32  smoothly transition into the flow orifice  42 . The wall of the orifice  42 , as described above, also tapers radially outward moving toward the necked-down end  44  of the seat ring  30 . All of these smooth and slightly tapered surfaces and smooth corners provide smooth flow paths for fluid passing through the orifice region  22  of the valve  10 . The smooth flow surfaces prevent formation of unstable or turbulent pockets of fluid that can detrimentally affect flow characteristics and performance of the valve.  
         [0030]    The replaceable valve seat ring  30  as disclosed herein permits use of a standard socket wrench or other such standard tool for installation and removal of the seat ring from a valve  10  for repair or replacement when damage to the ring has occurred. In addition, the disclosed seat ring produces much improved fluid flow characteristics both over and through the seat ring as compared to prior known replaceable valve seat designs. As will be evident to those having ordinary skill in the art and as noted above, the tool recess  50  can vary from that disclosed. As a further example, the recess can be a six-sided recess for accepting a tool such as an ALLEN wrench and yet perform adequately as disclosed herein. Other variations to the seat ring are also possible. Although the seat ring disclosed herein can be fabricated from numerous different materials, one preferred material is a sufficiently hard and exceptionally durable material known as Alloy 6.  
         [0031]    Although certain replaceable valve seat rings have been disclosed and described herein in accordance with the teachings of the present invention, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all embodiments of the teachings of the invention that fairly fall within the scope of permissible equivalents.

Technology Classification (CPC): 8