Abstract:
A method and apparatus protecting a water distribution system from main breaks caused by sudden pressure spikes in the distribution system. A surge suppressor apparatus may include a surge suppressor tank. The surge suppressor tank may be a hollow, cylindrical container adapted to retain liquid. The surge suppressor apparatus may also include a tee pipe integrally formed to the suppressor tank. The tee pipe is sized so that it connects to an underground supply pipe. End caps may be integrally formed to the suppressor tank. The end caps create an airtight seal in the surge suppressor tank.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE 
     This application claims priority to Provisional Patent Application No. 60/957,880 having a filing date of Aug. 24, 2007, entitled “Method and Apparatus for Water Surge Protection,” which is hereby incorporated by reference herein in its entirety. 
    
    
     FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     [Not Applicable] 
     MICROFICHE/COPYRIGHT REFERENCE 
     [Not Applicable] 
     FIELD OF THE INVENTION 
     Certain embodiments of the present invention relate to water surge protection. More specifically, certain embodiments of the present invention provide for protecting a water distribution system from main breaks caused by sudden pressure spikes in the distribution system. 
     BACKGROUND OF THE INVENTION 
     A conventional city water distribution system is a network of pumps, pipelines, storage tanks, fire hydrants, and the like. The water main pipes are typically buried underground, in dedicated easements. A water distribution system delivers quantities of water at pressures sufficient for supply customers and firefighting equipment while avoiding excess pressure which could cause leaks and pipeline breaks. Water customer services are attached to the water main, and water is carried from the water distribution system into customers&#39; homes or businesses. 
     Fire hydrants are typically fed by an underground supply pipe and typically include underground shut-off valves which control the flow of water to each hydrant. Fire hydrants contain manually operable valves which are operated by a fireman to release water from the underground supply pipe in an event of a fire or during a training exercise. Also, hydrants may be opened by city workers or others in order to clear sedimentation from the water mains. Typically, the hydrant valve is located underground. Except in tropical climates where the ground does not freeze, it is generally necessary to bury below the frost line all of the parts of the system which normally retain standing water or slowly moving freezable liquids. A drain valve is normally open, draining the hydrant barrel while the hydrant valve is closed. 
     The hydrant valve is usually controlled by a stem extending vertically from the buried valve and passing through the top of the hydrant. A shut-off auxiliary valve, which is separate from the hydrant valve, is usually provided with an access conduit extending vertically to a removable access cover located at ground level adjacent to the hydrant. The access cover is removed and a removable wrench, commonly known as a valve key, is inserted through the access conduit to operate the shut-off valve. 
     A water surge can be a severe problem in a distribution system. A water surge results when a valve at one point in a distribution system is opened or shut suddenly, creating shockwaves of moving water upstream and downstream of that valve. In addition, when a pump or other source providing pressure on the water in the main is actuated, additional flows are created or diminished. Since water is essentially incompressible, it does not absorb the energy of the shockwave, but transmits it throughout the distribution system to nearby or distant parts of the system which are not isolated behind a closed valve. The turbulence created by the shockwave seeks a release point. Elevated water tanks are common release points but often are not close to the source of turbulence. Without a planned release point, the turbulence may create its own release point at a weak point in the distribution system, causing a water main break or other damage to the distribution system. 
     A water surge is capable of parting joints, breaking water mains and other components of the system. Since the system is mostly buried, occasionally time is required to pinpoint the damage area and then correct the resulting damage. The water escaping from the damaged system can cause a pressure failure, a pavement collapse, or other damage. It is sometimes very dangerous to repair. The danger occurs with trench cave-ins during working and with the possibility of breaking, or causing an explosion of a gas or other utility line. 
     Water main breaks are a costly and time consuming problem for municipalities. A system and method for water surge protection may minimize the frequency of water main breaks. Thus, there is a need for a system and method for protecting a water distribution system from main breaks caused by sudden pressure spikes in the distribution system. 
     Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings. 
     BRIEF SUMMARY OF THE INVENTION 
     A system and method for water surge protection is provided for protecting a water distribution system from main breaks caused by sudden pressure spikes in the distribution system. 
     These and other advantages, aspects and novel features of the present invention, as well as details of an illustrated embodiment thereof, will be more fully understood from the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a schematic view of a water distribution system or a portion thereof, in accordance with an embodiment of the present invention. 
         FIG. 2  is a side view of an embodiment of a surge suppressor tank apparatus, in accordance with the present invention. 
         FIG. 3  is a flow chart of a method for installing the surge suppressor tank apparatus of  FIG. 2 . 
         FIG. 4   a  is a side view of an embodiment of a surge suppressor tank apparatus, in accordance with the present invention. 
         FIG. 4   b  is a front sectional view of an embodiment of a surge suppressor tank apparatus, in accordance with the present invention. 
         FIG. 4   c  is an exploded view of a portion of the surge suppressor tank apparatus of  FIG. 4   a , in accordance with the present invention. 
         FIG. 5  is a side view of an embodiment of a surge suppressing pipe apparatus, in accordance with the present invention. 
     
    
    
     The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, certain embodiments are shown in the drawings. It should be understood, however, that the present invention is not limited to the arrangements and instrumentality shown in the attached drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Certain embodiments of the invention may be found and/or used in a system and method for water surge protection. More specifically, certain embodiments relate to protecting a water distribution system from main breaks caused by sudden pressure spikes in the distribution system. 
     Referring to  FIG. 1 , a small water distribution system, or a portion thereof, generally indicated at  10 , comprises a water tower  11 , a water reservoir or well  12 , a processing or pumping station  14 , a water main  18  and branch lines  20  which carry the water from main  18 . A plurality of valves, indicated by diagrammatic circles  22 , are located at various places in the distribution system and are used to shut off the flow of water along its distribution line. In addition, water outlets  26 , are also located at various places in the distribution system. Outlets  26  may take on a variety of forms including a fire hydrant. Water distribution systems such as  10  are conventional; they have many outlets such as  26  and cover a wide distribution area. 
     Referring to  FIG. 2 , a surge suppressor apparatus  200  includes a surge suppressor tank  210  and tee pipe  231 . Surge suppressor tank  210  is cylindrical in shape and includes end caps  215 . Surge suppressor tank  210  and tee pipe  231  are manufactured as one piece. For example, surge suppressor tank  210  is welded to tee pipe  231 . Surge suppressor apparatus  200  may be formed of cast iron, ductile iron, or plastic (e.g., polyvinyl chloride), as well as other materials as will suggest itself. 
     Surge suppressor apparatus  200  is connectable to a branch line or supply pipe  240  using a coupler (not shown), or a standard clamp (not shown), or the like. The coupler or standard clamp may be formed of stainless steel, cast iron, ductile iron or plastic, among other things. Tee pipe  231  includes a base  230  which may be manufactured in varying diameters in order to match the particular diameter of supply pipe  240  where a main break occurs. For example, base  230  is manufactured from cylindrical pipe having a diameter of either 4, 6, 8, 10, or 12 inches. The branch section  220  of tee pipe  231  may also be formed of cylindrical pipe and vary in diameter. In one embodiment, the diameter of the base  230  of the tee pipe is the same diameter as branch section  220 . 
     Surge suppressor apparatus  200  is installed by cutting out and removing a section of the branch line or supply pipe  240 . The cut out section of supply pipe  240  may be at the location of a break in the pipe, for example, caused by sudden pressure spikes in the water distribution system. Couplers or standard clamps may be used to connect the ends  235  of the tee pipe  231  to the cut out ends  245  of supply line  240 . In one embodiment, surge suppressor apparatus  200  is installed so that surge suppressor tank  210  is vertically above supply line  240 . 
     Surge suppressor tank  210  is formed of a hollowed cylindrical container. The ends of suppressor tank  210  may be sealed by end caps  215 . End caps  215  may be welded, or otherwise securely attached to surge suppressor tank  210  to seal the tank. Suppressor tank  210  may have an opening  221  which leads to branch section  220  of the tee pipe. The horizontal length of surge suppressor tank  210  is approximately twice that of its diameter. Surge suppressor tank  210  provides a chamber of a predetermined volume which receives an increase in water volume during water surges. 
     Surge suppressor tank  210  is typically full of ambient air when the surge suppressor apparatus is installed. Air may be trapped within the surge suppressor tank  210 . The end caps  215  of the surge suppressor tank  210  maintain an airtight seal. When water flows into the surge suppressor apparatus  200  via supply pipe  240  and through the base  230  of the tee pipe at a greater pressure than ambient air pressure, the water level may rise up through the branch section  220  and into the surge suppressor tank  210 . The air within surge suppressor tank  210  may be compressed until pressure equilibrium occurs between the compressed air and the water flowing through base  230  of tee pipe  231 . At pressure equilibrium, the water level maintains a vertical height within surge suppressor tank  210 . In operation, upon a water surge, water is forced through branch section  220  of tee pipe  231  and into surge suppressor tank  210  against the compressed gas, compressing the gas even further. The surge suppressor tank thus serves as a shock absorber for the water surge. 
     In operation, one or more valves that are opened and/or closed rapidly may cause shockwaves of moving water through the water distribution system. If surge suppressor apparatus  200  were absent, the surge would act on, and possibly break or part, the mains within the water system. As will suggest itself, other surges can be caused by different flow characteristics in the line caused by pumps or other devices. After surge suppressor apparatus  200  is installed, however, the surge is diverted and arrested (or at least greatly attenuated) by surge suppressor tank  210  located above tee pipe  231 . When a surge occurs, water is driven upward through branch section  220  of the tee pipe  231  and into surge suppressor tank  210 . The air within surge suppressor tank  210  quickly compresses and then relaxes, absorbing the force of the surge. 
       FIG. 3  illustrates a flow chart of an exemplary method for installing a surge suppressor tank apparatus  200 , in accordance with an embodiment of the present invention. 
     First, at step  310 , the area surrounding a water release point in the water distribution system may be excavated. The water release point may be an area where a main break has already occurred, or the area may be chosen, in a preventive step, at a location so as to reduce the risk of future main breaks, among other things. Before excavating, water may need to be shut off using a shut-off valve (not shown) to stop water from passing through supply pipe  240 . Once the water is shut off, the area surrounding the water release point may be excavated by removing the overburden of soil, for example. 
     At step  320 , the section of supply pipe  240  is cut out and removed to provide an opening in the water distribution piping for receiving surge suppressor tank apparatus  200 . The section of supply pipe  240  which is removed may be the approximate horizontal width of the surge suppressor tank apparatus  200 . The section of supply pipe  240  that is cut out may be located where a main break has occurred or at the water release point, for example. 
     Next, at step  330 , surge suppressor apparatus  200  is installed. The appropriate surge suppressor apparatus  200  is chosen based on the material (e.g., stainless steel, cast iron, ductile iron, plastic, etc.) forming apparatus  200 . In addition, apparatus  200  is chosen based on the diameter of the supply pipe  240 . A cast iron surge suppressor apparatus  200  may be chosen if supply pipe  240  is cast iron. Additionally, the diameter of base  230  of tee pipe  231  may be the same diameter as that of supply pipe  240 . 
     In an embodiment, the ends  235  of the base  230  of tee pipe  231  are connected to the cut off ends  245  of supply pipe  240  by using standard clamps or couplers, or by welding together the joining ends  245  and ends  235  where the suppressor  200  is made from polyethylene, fusion welding of ends  245 ,  235  could be used. As understood, cast iron, PVC asbestos pipe, etc. is impossible to weld to a dissimilar material of the supply pipe  240 . Surge suppressor apparatus  200  may be installed so that surge suppressor tank  210  is vertically above supply line  240 . 
     Next, at step  340 , the excavated area surrounding the installed surge suppressor apparatus is covered with soil. After filling in the excavated area, supply pipe  240 , that was previously shut off, may be opened to permit water flow there through. The system once pressurized again may then be inspected for leaks prior to backfilling. 
     Referring to  FIGS. 4   a - 4   c , a surge suppressor apparatus  400  includes a surge suppressor tank  410  and tee pipe  417 . Tee pipe  417  includes a base  430  which may be manufactured in varying diameters in order to match the particular diameter of a supply pipe (e.g., supply pipe  240 ,  FIG. 2 ) where a main break occurs. For example, base  430  is manufactured from cylindrical pipe having a diameter of either 4, 6, 8, 10, or 12 inches. The branch section  420  of tee pipe  417  may also be formed of cylindrical pipe and vary in diameter. In an embodiment, the diameter of the base  430  of the tee pipe  417  is the same diameter as branch section  420 . In an embodiment, the diameter, as referred to above, is measured using the inside diameter of the cylindrical pipe. Of course, engineering specifications may be met as to sizing the suppressor  400  to adapt to the particular supply pipe. 
     Surge suppressor tank  410  is cylindrical in shape and includes circular end caps  415 . In certain embodiments, end caps  415  may be recessed from the outer ends of the cylindrical wall of tank  410 , as shown at  450 . For example, end caps  415  may be recessed 0.25 inches from the outer ends of tank  410 . Surge suppressor tank  410  includes six (6) cross braces  405  ( FIG. 4B ) to prevent end caps  415  from bowing. As will suggest itself, other means or structural members may be used to reinforce end caps  415 . Alternatively, tank  410  may be made similar to a conventional propane tank. 
     Surge suppressor tank  410  may include a test port  440  with an associated plug (not shown) for emptying the surge suppressor tank. For example, during a passavation process (citric acid bath) to coat the area of welds, the tank may be emptied. In another embodiment, port  440  may be used to test water/air ratios, among other things. However, the threaded connection between the port and plug must not allow air to escape. Surge suppressor apparatus  400  may be formed of stainless steel, for example. In addition, if apparatus  400  is made from carbon steel and an approved coating is used, the port and plug, and passavation are unnecessary. 
     Referring to  FIG. 5 , a surge suppressing pipe apparatus  500  includes an inner pipe  510  and an outer pipe  520 . Inner pipe  510  includes multiple perforations  515 . In an embodiment, the multiple perforations may be of uniform size and/or shape, as for example, ¾ inch circular holes which permit water to pass between pipes  510 ,  520 . Additionally, the multiple perforations may be uniformly placed on the inner pipe  510 . 
     Outer pipe  520  is of a larger diameter and surrounds inner pipe  510 . Pipe  520  is attached to inner pipe  510  via tapered ends  517  of outer pipe  520 . The surge suppressing pipe apparatus  500  may be manufactured in varying diameters in order to match the diameter of inner pipe  510  to the diameter of a supply pipe (e.g., supply pipe  240 ,  FIG. 2 ) where a main break occurs. For example, inner pipe  510  is manufactured from cylindrical pipe having a diameter of either 4, 6, 8, 10, or 12 inches. The outer pipe  520  may also be formed of cylindrical pipe and vary in diameter. For example, if the supply pipe where a main break occurs is 6 inches, a surge suppressing pipe apparatus  500  having an inner pipe  510  diameter of 6 inches and an outer pipe  520  diameter of 8 inches may be used. In an embodiment, the surge suppressing pipe apparatus is manufactured as one piece. In an embodiment, the diameter is measured using the inside diameter of the cylindrical pipe. 
     The attachment of the outer pipe  520  to the inner pipe  510  forms a seal. For example, outer pipe  520  may be welded to inner pipe  510 . 
     Outer pipe  520  is filled with batting material for suppressing surges forces that occur from water passing through perforations  515  of the inner pipe. In an embodiment, the batting material may be closed cell foam plastic. Alternatively, a layer of foam may be applied between pipes  510 ,  520 . In addition, air or another gas may fill a bladder that is disposed between pipes  510 ,  520 . Also, the portion of inner pipe  510  may be eliminated and batting material or other suppressing material may be secured to the inside wall of pipe  520 , as for example, where the pipes are made from polyethylene. Where the batting material is placed throughout the space between pipes  510 ,  520 , the suppressing effect on surges will be more effective. 
     The ends of the inner pipe  510  extend beyond the tapered sealing attachment of the outer pipe  520  onto the inner pipe  510 . For example, the ends of the inner pipe  510  may extend at least 4 inches beyond the attachment point  519  of the outer pipe  520  onto the inner pipe  510  to allow space for attaching the surge suppressing pipe apparatus  500  to a supply pipe (e.g., supply pipe  240 ). Surge suppressing pipe apparatus  500  may be formed of stainless steel, cast iron, ductile iron, or plastic (e.g., polyvinyl chloride), as well as other materials as will suggest itself. 
     In operation, one or more valves that are opened and/or closed rapidly may cause shockwaves of moving water through the water distribution system. If surge suppressing pipe apparatus  500  were absent, the surge would act on, and possibly break or part, the mains within the water system. As will suggest itself, other surges can be caused by different flow characteristics in the line caused by pumps or other devices. After surge suppressing pipe apparatus  500  is installed, however, the surge is diverted and arrested (or at least greatly attenuated) by the matted outer pipe  520  surrounding the perforated inner pipe  510 . When a surge occurs, water is driven upward through perforations  515  of the inner pipe  510  and into matted outer pipe  520 . The matting within outer pipe  520  quickly compresses and then relaxes, absorbing the force of the surge. 
     Thus, certain embodiments provide for a system and method for protecting a water distribution system from main breaks caused by sudden pressure spikes in the distribution system using a surge suppressor apparatus and/or a surge suppressing pipe apparatus. By using one or more of the surge suppressing apparatuses, municipalities may save time and money that may be spent fixing future main breaks. Certain embodiments provide for a cost efficient system and method for water surge protection. 
     While the present invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present invention without departing from its scope. Therefore, it is intended that the present invention not be limited to the particular embodiment disclosed, but that the present invention will include all embodiments falling within the scope of the appended claims.