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[0001]    This application claims priority from Provisional Patent Application Serial No. 60/435,433 filed Dec. 20, 2002, entitled “Wet Barrel Fire Hydrant Flow Preventer.” 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates generally to a flow prevention apparatus for damaged fire hydrants, and more particularly, to an adjustable flow prevention apparatus for a wet barrel fire hydrant where damage to the water system elements is avoided while shut off of water flow from a damaged hydrant is simultaneously achieved.  
           [0004]    2. Description of the Related Art  
           [0005]    There are two basic types of fire hydrants manufactured today. These two types are commonly referred to in the trade as the “wet” barrel or “California” fire hydrant and the dry barrel fire hydrant. As the name implies, wet barrel fire hydrants are always supplied with water under pressure from a municipal, or other supply, water system. As such, it is the practice to install this type of fire hydrant only in milder climates where there is no chance of freezing. Because wet hydrants are constantly supplied with water, however, damage to the hydrant can result in a considerable loss of water before the damaged hydrant is discovered and repaired.  
           [0006]    Where the climate is dry, or where drought conditions prevail for any length of time, manufacturers of wet hydrants have endeavored to provide flow cut off devices to prevent loss of water in the event of damage to the barrel, such as may result from a vehicle collision. Unfortunately, the probability of such events occurring is quite high due to the standard location of hydrants adjacent the street curbs to facilitate rapid access by fire department personnel in the event of a fire emergency. Therefore, in the construction of wet barrel hydrants, manufacturers have proposed the use of cut off valves that are actuated in response to a pressure drop which will occur when, for example, the barrel is broken off from the supply pipe. In other arrangements, a valve is actuated by a mechanical linkage between the barrel and the cut off valve so that when the barrel is removed, such as by a vehicular collision or similar event, the valve will be quickly shut to prevent any significant water loss.  
           [0007]    With these and other devices, however, damage to the pipes and valves in the system can occur as a result of the high pressure that these elements experience due to the sudden closing of a supply pipe when the cut off valve is actuated as a result of the abrupt change in flow velocity of the water. Such an abrupt change produces what is commonly referred to as water hammer. Water hammer refers to the pressure fluctuations associated with the change between the kinetic energy of moving water and pressure energy, which may be either positive or negative. When the water in the pipe is stopped abruptly, considerable force is exerted on the valve and oscillating shock waves are reflected back into the municipal water system. The tremendous forces associated with water hammer can destroy the valve and damage other seals and pipes throughout the water system.  
           [0008]    Accordingly, systems have been developed to reduce the effects of water hammer. In some systems, it has been proposed to provide an upstream cut off valve that can be actuated gradually or even manually to prevent such water hammer damage. These arrangements, however, can result in substantial down stream water loss through the broken hydrant which is clearly undesirable in areas suffering drought and may also require cut off of flow to undamaged hydrants as well.  
           [0009]    In other arrangements, water cut off devices have been proposed which are warranted to cut off flow to a damaged hydrant but such devices are often difficult and expensive to install particularly in older, established water systems. For example, U.S. Pat. Nos. 4,127,142 and 4,596,263 both disclose wet barrel systems that utilize a dash-pot assembly connected to a “swing check” or flapper type valve. The valve is biased toward the closed position by a spring and is held open and out of the flow passageway by a holding bar connected to the upper barrel of the hydrant. If the hydrant is sheared from its support, the holding bar releases the flapper valve and the spring urges the valve into the flow passageway. The valve then closes due to the resulting change in water pressure, while the dash-pot assembly prevents rapid closure of the valve.  
           [0010]    Although the systems disclosed by U.S. Pat. Nos. 4,127,142 and 4,596,263 reduce the effects of water hammer, they still have limitations. For example, if the hydrant is merely damaged, rather than completely sheared off, the holding bar may actually prevent the valve from closing. In addition, the above systems require an underground barrel with a lateral chamber to accommodate the arrangement of the dash-pot assembly. Such an arrangement makes the use of the disclosed systems more difficult and expensive to install with existing water systems and/or with systems of different sizes or types. Finally, once the dash-pot assembly is installed, the restrictive rate of closure of the flapper valve cannot be adjusted.  
           [0011]    What is needed then, is an adjustable cut off valve for a wet barrel hydrant which is simple to install and relatively inexpensive, and that will effectively cut off water flow without causing water hammer in the accompanying system. It is to such a device that the present invention is primarily directed.  
         SUMMARY OF THE INVENTION  
         [0012]    The present invention provides a fluid flow prevention apparatus for a wet barrel fire hydrant which is simple to install and relatively inexpensive, yet will effectively cut off water flow without causing water hammering of the system&#39;s elements. The fluid flow prevention apparatus includes a valve member for closing the flow passageway of a pipe connected to a wet barrel fire hydrant. The valve member is positioned in-line with the flow passageway of the pipe and is operably movable from an open to closed position upon damage to the hydrant. An adjustable damping member controls the rate of closing of the valve member to reduce the effects of water hammer when the valve member closes.  
           [0013]    The fluid flow prevention apparatus may also include a tube member extending through the in-line valve member. One end of the tube member is in fluid communication with the flow passageway of the pipe while the other end of the tube member is in fluid communication with the hydrant to allow reduced fluid flow through the tube member when the valve member is closed. Accordingly, a signal stream of fluid is provided from the tube member for identifying the damaged hydrant. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0014]    [0014]FIG. 1 shows an elevational view, partly in section, of an embodiment of the device of the present invention.  
         [0015]    [0015]FIG. 2 shows an elevational view, partly in section, of the embodiment shown in FIG. 1 with the valve in the closed position.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]    Referring to the figures, wherein like numerals represent like parts, there is shown in FIG. 1, a standard wet barrel hydrant  10  which is secured, for example, by threaded bolts  11  to a plate  14  which is mounted on the upper end of an underground barrel  12 . Typically, the plate  14  is attached to a break off bracket  16  which includes an inner, annular flange  17  engaging in a grove provided in an radially extending flange  19  formed on the upper end of the underground barrel  12  as shown. With this arrangement, in the event of a collision or other force imposed on the upper barrel or hydrant  10 , the flange  17  will yield to allow the plate  14  to be released from the upper end of the underground barrel  12 .  
         [0017]    Typically, the break off bracket  16  will be secured to the plate  14  by threaded bolts inserted through the threaded apertures  21 . The plate  14  has an opening with an inside diameter slightly smaller in size than the diameter of the upper end of the underground barrel  12 . With this arrangement, a guide member in the form of a plate or bar  18  may be secured to the edge of the opening of underground barrel  12  as at  23 . The manner of attachment may be by welding or any other suitable method of attachment. A tube  20 , which is threaded at opposite ends, extends through a central aperture  13  provided in the guide member  18 .  
         [0018]    A nut  25  is threadedly engaged on the tube  20 , on the upper end thereof, at a distance from the upper end of tube  20 . An adjustable damping member  22  is provided between the nut  25  and the underside of the guide member  18 . It will be understood, of course, that the guide member  18  may simply be a bar extending across the opening to the plate  14  at the upper end of the underground barrel  12 , or it may take the form of an apertured plate so that flow of water to the upper barrel  10  will be unimpeded.  
         [0019]    The lower end of the tube  20  is also threaded to cooperate with a nut  26  that is located at the base of an opening  32  extending centrally through an in-line valve member  28  of conventional construction. One such hydrant valve is described in our U.S. Pat. No. 3,980,097 of Sep. 14, 1976, the disclosure of which is incorporated herein by reference in its entirety. The term “in-line” as used herein to describe the valve member is defined as any valve that is non-hinged and aligned axially with the direction of fluid flow. As is conventional, the in-line valve member  28  includes a sealing disc  30  surrounding the central opening  32  formed in the in-line valve member  28 . The tube  20  extends through the opening  32  to connect and be secured to the in-line valve member  28  by the nut  26 . An additional attachment between the in-line valve body and the tube  20  may also be provided, such as by a dowel pin as shown at  34 .  
         [0020]    The in-line valve member  28  is, as noted above, of conventional construction and may include a set of a upstanding ears  36  which cooperate with a seating ring  38  which serves to guide the in-line valve  28  in its movement between open and closed positions in the valve housing, or shoe  40 . The valve housing  40  has an opening  42  which is in use supplied with water under pressure from a municipal or other supply water system. The outlet of the housing  40  at  44  will be closed when the seal  30  contacts under pressure the rim  46  of the seat  38  of the valve housing  40  effectively preventing water from entering the flow passageway of underground barrel  12 . Although housing  40  is shown in a horizontal configuration, the housing may also be vertical or of any other suitable configuration.  
         [0021]    As shown in FIG. 1, the in-line valve  28  is in an open position so that the water entering the valve housing  40  through its opening  42  will pass through the seat  46  to fill the underground barrel  12  as well as the aboveground barrel or hydrant  10 . Holding member  15  engages the tube  20  to maintain the in-line valve  28  in an open position, so that the valve will remain open for normal operation of the hydrant. Holding member  15  may be attached to hydrant  10  or to plate  14  as a separate or integral member, and has a predetermined retention force for maintaining valve  28  in an open position during normal hydrant operation. In the event that the upper barrel or hydrant  10  is removed, such as by collision with a vehicle, water would normally flow freely through the underground barrel  12  to the exterior and be lost. According to the present invention, however, holding member  15  is removed along with hydrant  10  releasing the tube  20 , and water pressure acting on the lower end portion of the in-line valve  28  will move the valve  28  upward toward a closed position bringing the sealing disc  30  into engagement with the seat  46  to cut off fluid flow from the valve housing  40  to underground barrel  12 .  
         [0022]    Because the valve member  28  is provided in-line with the flow passageway of underground barrel  12 , the flow of water around and over valve member  28  is generally uniform during closing of the valve. Accordingly, the water hammering effects associated with the closing of in-line valve member  28  are less than those produced by the closing of conventional hinged or flapper type valves where the water flow is non-uniform. To further prevent water hammer or sudden pressure buildup upstream of the valve housing  40 , the closing of the in-line valve member  28  is restrained by an adjustable damping member  22  disposed between the underside of the guide member  18  and the adjustable nut  25  mounted on the tube  20 .  
         [0023]    In the preferred embodiment, adjustable damping member  22  is a helical spring disposed, as shown, with one end of the spring in engagement with the underside of the guide member  18  and the other end resting on the upper side of the nut  25 . Other types of damping devices such as a tubular body filled with a viscous fluid can be disposed about the tube to provide a damping action on the upward movement of the in-line valve  28  in the event that hydrant  10  is accidentally removed. Adjustment of the damping action is advantageously effected by adjusting the nut  25  to increase or decrease the resistance to movement of the tube  20  through the opening  13  provided in the guide member or plate  18  and consequent movement of the in-line valve member  28  upwardly towards the valve seat  46 . Normally, the damping device will be under no compression in order to prolong the useful life of the damper.  
         [0024]    Referring now to FIG. 2, valve member  28  is shown in a closed position. Hydrant  10 , and plate  14  have been removed, such as by collision with a vehicle. Because holding member  15  is attached to either hydrant  10  or plate  14 , tube  20  has been released and water pressure has moved in-line valve member  28  into a closed position. Sealing disc  30  is shown in engagement with rim  46  effectively cutting off the main fluid flow to underground barrel  12 . Tube  20  allows reduced fluid flow (as shown with arrows) from housing  40  to the outside. Such an arrangement further reduces the effects of water hammer because a small amount of water is allowed to exit the water system through tube  20 . This small stream of water also provides an identification stream indicating that the hydrant is damaged and repair is needed.  
         [0025]    The designs of the different embodiments of the present invention allow existing water systems to be easily and inexpensively fitted with the flow prevention apparatus described herein because wet barrel fire hydrants with specially shaped underground barrels are not required due to the in-line positioning of the valve and damping member. As stated above, the damping member is also adjustable enabling additional control over the rate of closing of the valve member by simply adjusting the amount of resistance provided by the damping member. Accordingly, the damping member can provide effective resistance for reducing water hammer in water systems with pipes of various sizes, shapes, and diameters.  
         [0026]    Numerous characteristics and advantages have been set forth in the foregoing description, together with details of structure and function. While the invention has been disclosed in its preferred form, it will be apparent to those skilled in the art that many modifications, additions, and deletions, especially in matters of shape, size, and arrangement of parts, can be made therein without departing from the spirit and scope of the invention and its equivalents as set forth in the following claims. Therefore, other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended.

Summary:
The present invention provides a fluid flow prevention apparatus for a wet barrel fire hydrant which is simple and inexpensive to install and effectively cuts off water flow while reducing water hammer. The fluid flow apparatus includes an in-line valve member for closing a flow passageway connected to the hydrant that is operably movable from an open to closed position upon damage to the hydrant. An adjustable damping member controls the rate of closing of the valve member to reduce the effects of water hammer.