Abstract:
A freezeless wall hydrant has a fluid inlet end connected to a source of pressurized water, and a fluid outlet end. A check valve is placed in the bore of the valve body and is spring loaded to open only when extreme water pressure within the inlet valve lifts a spring loaded piston element to permit the highly pressurized water to move through the bore in the valve body and be relieved as it escapes rearwardly into the original source of pressurized water.

Description:
BACKGROUND OF THE INVENTION 
     Freezeless wall hydrants and faucets have long been in existence. They characteristically have a fluid closure valve located in the end of an inlet pipe located within the wall or a warmer interior area of the building of which the wall is a part. This closure valve is operated by an elongated rod connected to an exterior handle. The freezeless characteristics of the hydrant are caused by the closure valve shutting off the flow of water within the wall or building at a freezing temperature, with the residual water in the inlet pipe flowing by gravity outwardly through the conventional outlet drain of the hydrant. 
     The foregoing structure works very successfully except in situations where a hose or the like is attached to the outlet drain of the hydrant, whereupon the residual water is not able to easily flow by gravity out of the hydrant when the closure valve connected to the pressurized water is closed. With a hose attached during freezing weather, the residual water freezes within the hydrant, and the inlet pipe or related components thereupon rupture from the freezing conditions within the hydrant. 
     It has in recent times been recognized that the rupture of such a hydrant under freezing weather conditions does not take place because of the frozen water in the hydrant. Rather, the rupture results from the ice imposing severe pressure on the captivated non-frozen fluid in the inlet pipe. Thus, the increased pressure on this water by the expanded ice is the principal cause for the rupture of the hydrant. 
     Attempts have been made to permit some backflow to take place via spring loaded ball bearings. (U.S. Pat. No. 6,142,172), but calcium deposits on the ball bearings sometimes inhibit the process. 
     Accordingly, it is a principal object of this invention to provide a freezeless wall hydrant which has the ability to drain at least some of the residual water in a hydrant when, under freezing conditions, the residual water towards the exterior part of the hydrant freezes by reason of a hose or the like being attached to the discharge nozzle. 
     It is a further object of this invention to provide a relief valve for the captured residual water under the foregoing conditions to escape back towards the supply of pressurized water when the frozen water in the exterior of the hydrant creates excessive pressure on the remainder of the residual water in the hydrant. 
     These and other objects will be apparent to those skilled in the art. 
     SUMMARY OF THE INVENTION 
     A freezeless wall hydrant has an inlet pipe with one end connected to a source of pressurized water, a water discharge conduit, and an elongated control rod extending through the inlet pipe to open and close a fluid valve. A bore is inserted through the fluid valve with the bore being in communication with both the source of pressurized water and the interior portion of the inlet pipe. A check valve is placed in the bore of the valve body and is spring loaded to open only when extreme water pressure within the inlet valve lifts a spring loaded piston element to permit the highly pressurized water to move through the bore in the valve body and be relieved as it escapes rearwardly into the original source of pressurized water. The check valve is enclosed within a cylindrical housing and is force-fit into the bore of the valve body. The spring has a strength that it will open the bore to fluid flow in a rearward direction only when the pressure within the outlet portion of the inlet conduit is greater than that of the pressurized source of water normally located upstream from the valve closure. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a longitudinal sectional view of the hydrant of this invention; 
     FIG. 2 is a large scale sectional view of the valve body in an opened condition which controls flow of pressurized water through the hydrant; and 
     FIG. 3 is a sectional view similar to that of FIG. 2 but shows how the valve can allow high pressure backflow water downstream from the valve body to the supply water when ice in the hydrant compresses water adjacent the downstream side of the valve in a backflow direction. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The hydrant  10  in FIG. 1 has an elongated hollow water inlet tube  12  which has an interior end  14  and an exterior end  16 . A hollow valve fitting  18  is rearwardly secured to the interior end  14  of tube  12  and has a threaded end  20  adapted to be secured to a conduit connected to a source of pressurized fluid (not shown). The fitting  18  has an interior end  22  with external threads  24  and which terminate in a valve seat  26 . 
     A casting member  28  has a conventional vacuum breaker  30  secured thereto and is rigidly connected to the exterior end  16  of inlet tube  12 . A conventional fluid drain conduit  32  is located within casting member  28  and is in communication with the interior of tube  12 . Conventional threads  34  are located on the discharge end of conduit  32  to receive a conventional hose or the like. Casting member  28  also has a threaded aperture  36  which is adapted to receive a conventional bushing  38  which in turn receives packing  40  which is held in tight engagement with bushing  38  by packing washer  42  (FIG.  1 ). 
     Adjacent the interior end of valve fitting  18  is a valve body  44  adapted for longitudinal movement in the interior end of  14  of tube  12 . Valve body  44  has an interior end  46 , an exterior end  48  and an elongated center bore  50  extending therethrough (FIGS.  2  and  3 ). A shoulder  52  with center bore  54  is located in bore  50 . A compressible sealing ring  56  is located in bore  50  adjacent shoulder  52 . A T-shaped piston element  58  having a circular top  58 A and a rearwardly extending stem  58 B of narrower diameter, creating a void  58 C therearound. An internally threaded bushing  59  is frictionally mounted within the rearward end of bore  50 . A bore  59 A is located in bushing  59  adjacent the rearward end of stem  58 B of piston element  58 . Coil spring  61  is normally compressed between bushing  59  and piston top  58 A to compress sealing ring  56 . A space  60  is provided around the top  58 A of piston element  58  to allow the passage of fluid from center bore  54 , thence through space  60  when compression of ring  56  is relieved, as will be discussed hereafter. 
     A valve seat member  62  is mounted on screw  64  and has a center bore  66  and is received by the internal threads of bushing  59 . The screw  64  binds the sealing member  62  to bushing  59  and valve body  44 . 
     Threaded arms  67  extend rearwardly from body  44  and threadably engage the threads  24  on the interior end  22  of valve fitting  18 . 
     A plurality of spherical spline teeth  70  extend outwardly from space  68 . A conventional check valve member  72  extends around the spline teeth  70  and are adapted to engage the interior surface of the inlet tube  12 . The check valve member  72  conventionally permits fluid flow only in a direction towards the drain conduit  32 , but prevents fluid flow in the inlet pipe in opposite direction. 
     A conventional elongated rod control  74  is located within the inlet pipe  12  and has a rearward end  76  and a forward end  78 . Spline grooves  80  are formed in the rearward end  76  of the rod control and are adapted to engage the spline teeth  70  located at the forward end of the body  44 . A conventional handle wheel  82  is spline-mounted on the forward end  78  of rod control  74  and is held in place by conventional screw  84 . 
     In the event that a hose is attached to the fluid drain conduit  32  in freezing temperatures, the residual water which ordinarily would flow out of the conduit  32  if the hose were not attached when the valve member  42  is in a closed condition will be captured within the conduit  32  and the interior of tube  12 . This residual captured water will first begin to freeze in the discharge conduit  32  and adjacent the exterior end  16  of tube  12 . The presence of ice in that portion of the hydrant will cause excessive pressure possibly as high as 4,000 psi in unfrozen residual water in the end  14  of tube  12 . This is because water volume expands by about 8% as it turns to ice. Ordinarily, water under that much pressure would rupture at least the inlet pipe  12 . However, with the present invention, this increased pressure exerted on the residual water in the inlet pipe  12  occasioned by the formation of ice in the exterior end thereof will exert pressure on piston top  58 A which will compress spring  61  against bushing  59  and thus releases the compression of ring  56 . This will permit the highly compressed fluid in the rearward end of tube  12  to flow around the ring  56 , thence around the top  58 A through space  60 , thence around spring  61 , thence through bore  59 A, thence the center bore  66  of screw  64 , and thence into the interior of the water supply in valve fitting  18 . The water pressure in valve fitting  18  is normally in the range of 55 psi, so the above process will continue to balance the water pressure on both ends of the valve body  44 , thus eliminating any rupture of the tube  12  caused by the freezing phenomenon. 
     Thus, from the foregoing, it is seen that this invention will keep the ordinary freezeless hydrant from becoming ruptured whenever a hose or the like is inadvertently left on the discharge conduit thereof. This successful result takes place because the formation of ice in such a hydrant under those conditions will permit the back flow of residual water in the hydrant to move through the otherwise closed hydrant valve into the original source of pressurized water. This relief of pressure will prevent the hydrant from rupturing under the freezing conditions. It is therefore seen that this invention will achieve all of its stated objectives.