Patent Document

BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to fire hydrants and more particularly to a fire hydrant with a unique valve seat flange and a method for manufacturing the same.  
         [0002]     Fire hydrants are commonplace in our society providing a ready source of water to, among other things, help confront fire hazards. Fire hydrants typically remain idle for long periods of time. As a result, the internal workings of the hydrant must be able to withstand long periods of time in the presence of water without corroding or otherwise becoming nonfunctional.  
         [0003]     With conventional fire hydrants, the flow of water through the hydrant is controlled by a valve. The valve is typically located below ground level within the hydrant shoe. A conventional valve includes a valve seat that is threaded in place within or adjacent to the hydrant shoe. The threaded seat permits the valve to be removed when maintenance is required. For example, the valve can be removed to permit replacement of the valve seal or to permit installation of a new valve. To ease removal of the valve, the valve seat is typically threadedly seated within a brass (or bronze) liner. The brass liner provides brass threads that resist corrosion and facilitate removal of the valve even after extended periods of time. Often, the valve seat is also brass so that the threaded interface between the valve seat and the brass liner includes intermeshing brass threads.  
         [0004]     In many conventional constructions, the brass liner is sandwiched in one way or another between a flange at the lower end of the standpipe and the hydrant shoe. The typically sandwiched construction provides a number of part interfaces that provide numerous potential leakage paths. Further, the sandwiched construction may not provide the strength desired in some applications. Additionally, the separate brass liner increases parts inventory and complicates the assembly process.  
       SUMMARY OF THE INVENTION  
       [0005]     The aforementioned problems are overcome by the present invention wherein a fire hydrant is provided with a valve seat flange having an integral liner. In one embodiment, the valve seat flange is disposed between the standpipe and the hydrant shoe, and includes a threaded brass liner that is insert cast as an integral part of the valve seat flange.  
         [0006]     In one embodiment, the valve seat flange includes an internally threaded standpipe neck for threadedly mounting the valve seat flange to the lower end of the standpipe and planar base for connecting to the hydrant shoe. The liner may include a contoured outer peripheral region that interlocks with the valve seat flange to reduce the likelihood of rotation of the liner with respect to the valve seat flange.  
         [0007]     The valve seat flanges may be manufactured in a process including the steps of: (a) manufacturing the liner, (b) incorporating the liner into a core with the outer peripheral region of the liner exposed, (c) placing the integral core/liner into the valve seat flange mold, (d) forming the valve seat flange around the liner with the valve seat flange entrapping the outer peripheral region of the liner.  
         [0008]     The present invention provides a hydrant with a simple and effective valve seat that provides the assembly with increased strength and also reduces the number of potential leak paths. Additionally, the integral liner eliminates the need for handling and assembly of a separate liner. The integral liner is also entrapped within the valve seat flange, thereby reducing the potential for axial movement of the liner with respect to the flange.  
         [0009]     These and other objects, advantages, and features of the invention will be readily understood and appreciated by reference to the detailed description of the preferred embodiment and the drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a cross-sectional view of a fire hydrant incorporating a valve seat flange in accordance with an embodiment of the present invention.  
         [0011]      FIG. 2  is a cross sectional view of the lower standpipe with the valve seat flange.  
         [0012]      FIG. 3  is a top plan view of the valve seat flange.  
         [0013]      FIG. 4  is a cross sectional view of the valve seat flange taken along line IV-IV of  FIG. 3 .  
         [0014]      FIG. 5  is a top plan view of the valve seat liner.  
         [0015]      FIG. 6  is a cross sectional view of the valve seat liner taken along line VI-VI of  FIG. 5 .  
         [0016]      FIG. 7  is a cross sectional view of the valve seat liner taken along line VII-VII of  FIG. 5 .  
         [0017]      FIG. 8  is a cross sectional view of casting apparatus for use in manufacture of one embodiment of the present invention.  
         [0018]      FIG. 9  is a top plan view of the rough valve seat flange after casting and before machining.  
         [0019]      FIG. 10  is a cross sectional view of the rough valve seat flange taken along line X-X of  FIG. 9 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]     A fire hydrant incorporating a preferred embodiment of the present invention is shown in  FIG. 1  and generally designated  10 . The fire hydrant  10  includes a valve  12  mounted within a valve seat flange  14 . The valve seat flange  14  is disposed between the standpipe  16  and the hydrant shoe  18 , and includes an integral liner  20  for threadedly receiving the valve assembly  22 . The integral liner  20  provides an integrated corrosion resistant liner for use in seating the valve assembly  22 . The valve assembly  22  is threaded into the liner  20 .  
         [0021]     Fire hydrants are well known and accordingly will only be described herein to the extent helpful in disclosing the present invention. For purposes of disclosure, the present invention is described in connection with a conventional WaterMaster® fire hydrant available from East Jordan Iron Works of East Jordan, Mich. The present invention is, however, readily incorporated into a wide variety of other fire hydrants, and the present invention should be interpreted as being limited to any particular fire hydrant construction. In summary, the fire hydrant  10  of the illustrated embodiment includes a hydrant shoe  18  which functions as an inlet, a valve seat flange  14  to receive the valve assembly  22 , a lower standpipe  16 , an upper standpipe  24  and a top bonnet  26  that supports, among other things, the nozzle  28  and valve operating nut  30 .  
         [0022]     As discussed above, the valve seat flange  14  is interposed between the lower standpipe  16  and the hydrant shoe  18  to operatively receive the valve assembly  22 . The valve seat flange  14  includes a somewhat tubular body  32  having a standpipe neck  34  at its upper end and a base flange  36  at its lower end. Referring now to  FIG. 2 , the standpipe neck  34  is interconnected with the lower standpipe  16 . In the illustrated embodiment, the lower standpipe  16  is threadedly connected with the valve seat flange  14 . More specifically, in this embodiment, the lower standpipe  16  includes external threads  36  that are interfitted with internal threads  38  defined in the standpipe neck  34 . The base flange  36  generally includes a planar peripheral flange  50  surrounding an annular rim  52 . The peripheral flange  50  is generally planar providing a flat surface for mounting to the upper mounting surface of the hydrant shoe  18 . The peripheral flange  50  defines a plurality of bolt holes  51  for intersecuring the valve seat flange  14  and hydrant shoe  18 . The rim  52  is closely fitted within the hydrant shoe  18  to center the valve seat flange  14  and strengthen the connection between the valve seat flange  14  and the hydrant shoe  18 . A lower o-ring  54  is preferably fitted to the base flange  36  within and an o-ring seat  56  to facilitate a leaktight seal between the valve seat flange  14  and the hydrant shoe  18 . The valve seat flange  14  includes a first reduced diameter portion  40 , which entraps the integral liner  20 . The upper end of the first reduced diameter portion  40  defines a surface to function as a stop for the threaded lower standpipe  16 . As described in more detail below, the valve seat flange  14  is preferably formed about the liner  20  so that the two elements are integral with one another. The liner  20  is generally ring-shaped defining internal threads  42 . The liner  20  and its internal threads  42  are dimensioned to threadedly receive the valve assembly  22 . The liner  20  is preferably manufactured from bronze, but may be manufactured from other materials having sufficient strength and corrosion resistance. For example, the liner may be brass in some applications. In this embodiment, the liner  20  is manufactured in rough form for casting and is machined after incorporation into the valve seat flange  14 . The rough liner  20  is shown in  FIGS. 5-7 . The rough liner  20  of this embodiment includes a plurality of internal lugs  62   a - d  that interlock with the core  100  to reduce the possibility of the liner  20  rotating within the core  100 . The lugs  62   a - d  protrude from the inner circumferential surface of the liner  20 . As described in more detail below, the inner circumferential surface is ultimately machined to provide threads for interfacing with the valve assembly  22 . This machining process removes the lugs  62   a - d . The rough liner  20  may also define a plurality of grooves  64   a - f  on the outer circumferential surface of the liner  20 . The grooves  64   a - f  interlock with the valve seat flange  14  when valve seat flange  14  is formed about the liner  20 . This reduces the possibility of the liner  20  rotating within the valve seat flange  14 . The grooves  64   a - f  may be replaced by notches, protrusions or other variations in shape that provide an interlock between the liner  20  and the valve seat flange  14 . The valve seat flange  14  includes a second reduced diameter portion  44 . The second reduced diameter portion  44  is dimensioned to closely receive the valve seat  46  of the valve assembly  22 . The interior surface of the second reduced diameter portion  44  is preferably machined to provide a smooth, clean surface to interface with the o-rings  48   a - b  of the valve seat  46 . The valve seat flange  14  also defines an annular drain recess  57  and a pair of drain holes  58   a - b  that permit water to drain from the standpipes  16 ,  24  and bonnet  26  when the valve assembly  22  is in the closed position. The drain mechanism is generally conventional and therefore will not be described in detail. Suffice is to said, however, that the drain recess  57  and drain holes  58   a - b  in the illustrated embodiment are defined in the second reduced diameter portion  44  so that they are disposed between the valve seat o-rings  60   a - b.    
         [0023]     A preferred method for manufacturing the valve seat flange  14  using a casting process will now be described with reference to  FIGS. 8-10 . The rough liner  20  is manufactured separately from the remainder of the valve seat flange  14  (See  FIGS. 5-7 ). The liner  20  is preferably cast from bronze or brass using conventional casting tools and methods, but may be machined or otherwise formed. The liner  20  is not necessarily manufactured from bronze or brass and may be manufactured from other materials having sufficient strength and corrosion resistance.  
         [0024]     The liner  20  is insert cast into valve seat flange  14  using a conventional casting core, for example, sand core  100 . The core  100  maintains the liner  20  in the correct position during the process of casting the valve seat flange  14 . The rough liner  20  is integrated into the core  100  using conventional core manufacturing techniques and apparatus. As shown in  FIG. 8 , the rough liner  20  is integrated into core  100  with its outer peripheral region exposed, and more specifically, that portion of the outer periphery of the liner  20  that is to be entrapped within the valve seat flange  14 .  
         [0025]     The valve seat flange  14  is cast, for example, from a ductile iron. In this embodiment, the valve seat flange  14  is cast using a conventional sand casting apparatus  90 . In summary, a pattern (not shown) of the valve seat flange  14  is preformed. The pattern is shaped to occupy the space of the valve seat flange  14  and the core  100 . The pattern is pressed into the cope  102  and drag  104  to define opposed portions of the casting cavity  106 . A runner gate system (not shown) is also defined in the cope  102  to permit the desired molten material to be poured into the cavity  106 . Before closing the cope  102 , the core  100  is placed in the cavity  106  where it remains during the casting process. The cope  102  is then closed on top of the drag  104  with the cope  102  and drag  104  cooperatively defining a cavity  106  surrounding at least portions of the core  100  in the shape of the valve seat flange  14 . Molten material, such as ductile iron, is then poured into the cavity  106  through runner gate system. The molten material flows down into the cavity  106  where it is permitted to cure. After curing, the completed part is removed from the cope  102  and drag  104 . The core  100  is broken apart and removed from within the part leaving behind the rough liner  20  entrapped within the valve seat flange  14 . The rough valve seat flange  14  is shown in  FIGS. 9 and 10 . As shown, the liner  20  continues to include lugs  62 - a - d . In addition, the interfacing surfaces of the valve seat flange  14  remain rough. The valve seat flange  14  is then finished as desired, for example, by machining to remove the runner gate system and any undesired rough surfaces. In this embodiment, the finishing process includes the step of forming internal threads  38  in the standpipe neck  34  to threadedly receive the lower end of the lower standpipe  16 . Also, the bottom surface of the base flange  36  is machined to provide a smooth interface with the top flange of the hydrant shoe  18 . Similarly, the interior surface of the second reduced diameter portion  44  is machined to provide a smooth interface with the valve seat  46  and valve seat o-rings. The annular drain recess  57  and drain holes  58   a - b  are also preferably, but not necessarily, machined into the valve seat flange  14  after the casting process is complete. Further, in this embodiment, the inner circumferential surface of the liner  20  is machined to form threads  42 . The threads  42  may, however, be formed before or after the valve seat flange  14  casting process.  
         [0026]     The valve seat flange  14  is installed in the hydrant  10  by aligning flange  14  and shoe  18  so that the rim  52  is fitted within the shoe  18 . The valve seat flange  14  is then secured to hydrant shoe  18 , for example, by bolts or other fasteners (not shown) extending through the bolt holes  51  in the base flange  36  and the corresponding top flange of the hydrant shoe  18 . The valve assembly  22  may then be installed within the valve seat flange  14 . The valve seat  46  is threaded into the liner  20  creating a brass-on-brass threaded interface. The valve seat  46  is threaded into the liner  20  until the bottom end of the valve seat  46  abuts the upper surface of the second reduced diameter portion  44 . This helps to ensure proper positioning of the valve assembly  22  within the valve seat flange  14 . The lower standpipe  16  is then installed on the valve seat flange  14 . The threaded lower end of the standpipe  16  is threaded into the standpipe neck  34 . The lower standpipe  16  is threaded into the valve seat flange  14  until the bottom end of the lower standpipe abuts the top surface of the first reduced diameter portion  40 . In that way, the first reduced diameter portion  40  helps to ensure proper positioning of the lower standpipe  16 . The remaining portions of the hydrant  10  are assembled in a conventional manner.  
         [0027]     The above description is that of a preferred embodiment of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular.

Technology Category: 4