Patent Abstract:
A fire hydrant of the “dry” barrel type having an improved means of draining the barrel after the hydrant has been used. The hydrant is provided with a drain passageway communicating the interior of the hydrant barrel to the exterior. A diffuser is attached to the hydrant at the drain passageway and receives water therefrom. The diffuser eliminates the need for force flushing the drain passageway and the localized draining of the hydrant barrel, thus eliminating soil erosion in the vicinity of the hydrant. Furthermore, the diffuser protects the interior components of the hydrant from entrance of foreign matter.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     The present invention generally relates to hydrants, but more specifically to the draining of fire hydrants after use. The most common type of fire hydrant manufactured today is the “dry” barrel fire hydrant. The dry barrel hydrant gets its name from the fact that water is pumped or drained from the hydrant barrel when the hydrant is not in use to prevent corrosion of the interior and freezing of the hydrant in winter weather. Water flow into and out of the hydrant barrel is controlled through the manipulation of a main valve located in the base of the hydrant. When the main valve is opened, the barrel is pressurized and available for use. When the main valve is closed, water enclosed within the barrel is drained. 
     Since the main valve of the dry barrel hydrant is located underground, below the freeze line, the hydrant incorporates an automatic means for draining the barrel above the main valve after each use. The means for draining the hydrant barrel is usually an automatic drain valve working in conjunction with the operation of the main hydrant valve. The drain valve is automatically open, allowing water to drain from the interior of the barrel to the exterior of the hydrant, when the main hydrant valve is closed, and closed when the main hydrant valve is open. This process will maintain the hydrant barrel dry at all times during non-use and prevent corrosion or freezing of the hydrant. 
     Drain valves for fire hydrants may be of the slide valve type, spring loaded valve type, sliding tube type, or cam operated to open and/or closed type. The most predominantly used type of drain valve is the slide valve type. In this type of drain valve, the valve consists of a drain passageway and a drain valve facing strip. The drain passageway extends from the interior of the barrel, at a location just above the main valve, through the barrel or base of the hydrant to the exterior of the hydrant. The drain valve facing strip is located on a longitudinal rib extending upward from the main valve. The rib and drain valve facing strip are positioned such that the facing strip is either covering or not covering the opening of the drain passageway depending upon the position of the main valve. 
     In dry barrel hydrants, the drain valves operate automatically such that the drain passageway is either open, providing for drainage, or closed. Therefore, the passageway remains open whenever the main hydrant valve is closed. Consequently, when a hydrant is located in an area where water may collect for any period of time above the hydrant main valve, and thus the drain passageway, there is the opportunity for water or water with dirt, grit, and other foreign matter to backflow through the drain passageway into the hydrant. Backflow can cause damage to the hydrant&#39;s main valve or corrosion to the interior parts of the hydrant. There is also a danger of subsequent freezing if the backflow pressure is sufficient to raise the water level in the barrel above the freezing line. 
     To prevent backflow of water through the drain passageway some hydrants have incorporated backflow preventer valves. However, these devices are prone to mechanical failure, corrosion, and clogging by foreign matter. Failure of the backflow preventer exposes the hydrant to the backflow of ground water and may result in the release of high pressure water during hydrant use, resulting in water and water pressure loss and in destruction erosion of the soil surrounding the hydrant. 
     Clogging of the drain passageway is also an issue in wet areas where backflow of water and/or water with dirt, grit, and other foreign matter is likely. Clogging of the drain passageway prevents drainage of the barrel after use of the hydrant and can lead to corrosion of the interior of the hydrant and/or freezing of the water trapped in the hydrant barrel. In an attempt to prevent clogging of the drain passageway many hydrant drain valves are constructed of a force-flushing design. By this design, the drain valve remains open momentarily as the main hydrant valve begins to open and/or just before the main hydrant valve closes so that full main pressure is applied to the drain passageway to clear foreign material from the drain valve and passageway before the hydrants next use. However, this flushing is not guaranteed to remove all foreign matter and often results in destructive erosion of the soil surrounding the hydrant. 
     After use of the dry barrel hydrant, all water is automatically drained from the barrel into the immediate vicinity surrounding the hydrant. The flow of the water draining from the hydrant may result in general or localized erosion of the soil in the area surrounding the hydrant. Flushing and failure of backflow preventers results in destructive erosion of the soil surrounding the hydrant. Since the vast majority of hydrants are located in cities along sidewalk and roadways, the effect of this erosion over time results in undermining and eventual failure of these surfaces. 
     BRIEF SUMMARY OF THE INVENTION 
     Broadly stated the present invention relates to an improvement in a hydrant and, more particularly, to the addition of an improved drainage arrangement for allowing drainage of a dry barrel hydrants over a larger drainage field, thus, preventing erosive effects to the soil surrounding the hydrant, and for the prevention of the backflow of foreign matter into the hydrant. This drainage arrangement includes a diffusion means connected to the exterior of the hydrant at the outer end of the drain passageway(s). 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a fire hydrant embodiment. 
     FIG. 2 is an enlarged fragmentary vertical sectional view of the lower portion of the fire hydrant of FIG.  1 . 
     FIG. 3 is a perspective view of an external diffuser for use with the fire hydrant of FIG.  1 . 
     FIG. 4 is an enlarged fragmentary vertical sectional view of the lower portion of the fire hydrant of FIG. 1 incorporating a permeable insert within the drain passageway. 
     FIG. 5 a perspective view of an external diffusing wrap in use on the fire hydrant of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     While the invention is claimed in connection with one or more preferred embodiments, it will be understood that the invention is not limited to those embodiments. On the contrary, the invention includes all alternatives, modifications, and equivalents as may be included within the spirit and scope of the appended claims. 
     Referring now to FIG. 1, a fire hydrant generally designated at  10  and having a barrel  12 , a base  14 , a bonnet section  16 . The barrel  12  is usually made in two sections, an upper section  18  and a lower section  20 . One or more nozzle outlets  22  are provided on the upper barrel section  18  to which a hose may be connected. The main hydrant valve is operated by an operating nut  26  projecting outwardly of the bonnet  16  and operatively connected to the reciprocating valve stem of the hydrant to be described later. 
     Referring now to FIG. 2, the lower section  20  of the barrel  12  is provided with a flanged end  28  arranged to be bolted by bolts  30  to the flanged end  32  surrounding an upwardly opening mouth  34  of the hydrant base  14 . The hydrant base  14  herein depicted is referred to as a hydrant shoe. The hydrant base  14  is provided with an inlet end  36  having a flange  38  surrounding the same for attachment to a water pressure supply. 
     As shown in FIG. 2 a valve stem  40  extends downwardly through the barrel  12  and is connected at its upper end to the operating nut  26  so that rotation of the nut  26  causes the valve stem  40  to move vertically up or down. Attached to the lower end of the valve stem  40  is the main hydrant valve member generally designated at  42 , the main hydrant valve member being arranged to cooperate with the main hydrant valve seat  44 . The main hydrant valve member  42  includes a lower valve plate  48 , a rubber or rubber-like valve element  50 , and an upper valve plate  52 . The upper valve plate  52  includes one or more longitudinally and upwardly extending ribs  54 . In this example, the valve plate  52  includes two ribs  54 . The ribs  54  ride in longitudinal grooves provided in the valve seat ring  56 . Attached to the ribs  54  is the drain valve facing  58 . The drain valve facing  58  is made of rubber or a plastic material such as polyethylene. 
     A drain passageway  60  extends through the base  14  and the hydrant seat ring  56 . The drain passageway  60  opens at one end to the exterior of the hydrant  10  and at the other end to the interior of the barrel  12  above the main hydrant valve seat  44 . There may be one or more of these drain passageways  60 . In the hydrant shown in FIG. 2 there are two. The drain valve facing  58  attached to the main hydrant valve member  42  is positioned in such a manner as to control water flow through the drain passage  60 , thus providing a drain valve means that closes the passageway  60  when the main valve member  42  is open and opens the passageway  60  when the main hydrant valve  42  is closed. 
     Referring now to FIG. 3, the diffuser  61  includes a mesh screen  62 , a perforated tube  63 , and a diffuser connection  64 . The mesh screen  62  completely encloses the perforated tube  63  and is mechanically sealed to the tube near or at the diffuser connection. The perforated tube  63  is mechanically attached to the diffuser connection  64 . The diffuser connection  64  is selected such that it can be attached to one of the hydrant&#39;s drain passageways  60 . 
     In operation, water drains from the hydrant barrel  12  through the drain passageways  60 , through the diffuser connection  64 , into the perforated tube  63 , out the perforations in the perforated tube  63 , into the mesh screen  62 , and then out the perforations in the mesh screen  62  into the drainage field surrounding the fire hydrant  10 . To form a tight and leak free connection between the diffuser  61  and the drain passageways  60 , the diffuser connection  64  may either be smooth and of a size which will fit tightly into the passageway  60  or be threaded to form a tight connection with the threaded interior walls of the drain passageway  60 . In a preferred embodiment, the perforated tube  63  is constructed of ½-inch PVC tubing incorporating ⅜-inch holes ½ to 1½ inches apart. Also in the preferred embodiment, the mesh screen is made of a vinyl coated polyester with a mesh size between 1 and 60 mm. In this embodiment a material with a low rate of diffusion and small aperture size would be desired to prevent soil erosion and entry of sand, grit, or foreign material into the hydrant during conditions conducive to backflow. The length of the diffuser varies depending on the requirements for a particular hydrant. For example, diffuser  61  is cylindrical in shape and approximately three feet in length. 
     Although FIG. 2 illustrates the preferred embodiment of the diffuser  61 , several alternate embodiments may also be used. For example, instead of using the vinyl coated polyester, the mesh screen  62  may be constructed of another material such as a plastic, fiberglass, or canvas. The mesh screen  62  may also be replaced by either perforated hose or a permeable material such as foamed vinyl plastic, namely, polyvinyl chloride (PVC), or a foamed rubber material. The selection of the mesh screen material is based on the desired rate of diffusivity and aperture size. Also, in the alternative, the perforated tube  63  may be constructed of another material such as a plastic or metal. Also, the size and number of the perforations in the perforated tube  63  may altered to increase or decrease the rate of drainage. 
     Referring now to FIG. 4, the drain passageway  60  is filled with a permeable insert  66 . The insert  66  may be formed externally and put into the drain passageway or formed directly within the passageway. In a preferred embodiment, the insert  66  is formed of a permeable material such as foamed vinyl plastic, such as polyvinyl chloride (PVC), or a foamed rubber and secured within the drain passageway  60  with an adhesive  65 . The insert material is selected based on the desired rate of diffusivity and aperture size. In this embodiment a material with a low rate of diffusion and small aperture size would be desired to minimize soil erosion and prevent entry of sand, grit, or foreign material into the hydrant during conditions conducive to backflow. 
     Referring now to FIG. 5, a wrap  68  is attached around the exterior of the hydrant  10  effectively covering the drain passageways. In a preferred embodiment, the wrap  68  is formed of a permeable material such as foamed vinyl plastic, such as polyvinyl chloride (PVC), or a foamed rubber and secured around the hydrant with metal or plastic straps  70 . The wrap material is selected based on the desired rate of diffusivity and aperture size. In this embodiment a material with a low rate of diffusion and small aperture size would be desired to minimize soil erosion and prevent entry of sand, grit, or foreign material into the hydrant during conditions conducive to backflow. 
     While particular elements, embodiments and applications of the present invention have been shown and described, it is understood that the invention is not limited thereto since modifications may be made by those skilled in the art, particularly in light of the foregoing teaching. It is therefore contemplated by the appended claims to cover such modifications and incorporate those features which come within the spirit and scope of the invention.

Technology Classification (CPC): 4