Abstract:
A system and method for dewatering an area in which a catch basin is situated within the area to collect water and conduit conveys the collected water to an elongated discharge chamber having a muzzle at a distal end in communication with a desired ouffall body and a substantially closed proximal end. Compressed air released into the proximal end of the discharge chamber forcibly discharges water out of the discharge chamber via the muzzle and into the outfall body to dewater the area. A vent permits escape of air as the discharge chamber fills. Backflow prevention valves maintain discharge out of the muzzle and prevent any water from the outfall body from flowing back into the discharge chamber.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority from U.S. Provisional Application Ser. No. 60/789,000, filed Apr. 4, 2006. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a dewatering system and method. More particularly, the present invention is a surface water collection and pumping system employing the release of compressed gas through a discharge chamber. 
       BACKGROUND OF THE INVENTION 
       [0003]    Storm water systems are generally designed to provide adequate dewatering of surface areas while addressing related issues such as protection of watershed water quality, erosion, etc. Integral within any system plan or design is an assessment of the topography of the site for grading within the area of concern. Of course, regions of consistently flat topographies, such as the low-lying areas of the city of New Orleans, provide particular challenges to storm water removal. In such topographies, pumping stations may be required for dewatering, transporting water both horizontally and vertically. 
         [0004]    In situations where a dewatering system is responsible for large surface areas, the associated pumping systems must be capable of pumping large volumes of fluid. Such larger systems typically require robust pumping stations having sizable pumps, motors, power supplies, supporting piping, and other equipment. Such pumping stations have been used in a variety of circumstances, such as the evacuation of seepage from low elevation areas, removal of storm drainage, transfer of sewage, maintenance of canal systems, etc. Some pumping stations may be temporarily installed for the pumping of mines or deep wells. Somewhat similar dewatering systems may be found on ships, sometimes using bilge pumps with catch basins, and other times as a bilge evacuation or fire main eductor system. 
         [0005]    In general, there are two types of pumping stations seen in civil infrastructures: wet-pit and dry-pit. In a wet-pit station, submersible pumps are immersed in water contained within a sump or wet well. Submersible pumps have been generally preferred for storm water removal. Dry pit stations provide both a wet well and a dry well. The wet well stores the water to be pumped, which is transferred to the dry well by piping. The two stage process of dry pit stations make them more expensive, but enables maintenance of the pump without removal from the wet well. The pumps conventionally used in these stations may be classified by the type of flow, such as axial flow, radial flow, or mixed flow. The type of flow indicates the type of device used to impart energy to the water. Axial flow pumps typical use propellers to create a low pressure or head with a high volume flow in the direction of the propeller axis. Radial flow pumps typically use impellers to create a high pressure or head with a centrifugal flow about the axis of the impeller. Mixed flow pumps use a combination of the above two types of flow. Each of these types of pumps requires a motor to drive the propeller or impeller through an axle or drive shaft. 
         [0006]    Of course, both of the above approaches involves considerable infrastructure. Another hazard that the conventional pumping systems face is the presence of sediment, debris, sand, or other such objects within the fluid to be pumped. Sediment can damage a pump propeller or impeller. Most pumps stations require a significant filtering system to clean the fluid prior to it being pumped. However, filters increase the resistance to flow, causing the pump to work harder and the motor to consume greater power for the volumetric flow pumped. In some cases, filters may become clogged. In general, conventional pumps may require additional maintenance and expense of operation when used in an unclean environment. Unfortunately, an unclean environment is typical for most dewatering systems. Filters and grates designed to protect pumps are common problems for dewatering systems. 
         [0007]    Another aspect is the need for the supporting systems of a pumping system. Most conventional pumping systems require an ongoing supply of power to maintain operation of the motors driving the pumps. Even eductors require a minimum level of fire main pressure and flow in order to generate a vacuum at the intake port of the eductor. Yet in the conditions requiring dewatering, such as flooding caused by storms, or a flooding casualty aboard ship, the power supply may be unreliable. 
         [0008]    Some other approaches to pumping fluids have involved the use of air lift pumps or equivalent structures. Air lift pumps commonly create a multiphase mixture of gas and fluid within a vertical pipe, the mixture having a lower density than the surrounding fluid. The difference in density can induce the mixture to travel up the vertical pipe and ultimately to discharge. Other efforts involve creating a pressure differential between vessels in a closed system to move fluid from a high pressure vessel to a lower pressure vessel. These structures are not well adapted to the environments common in large volume, open system dewatering, with large surface areas, debris laden water, the need for horizontal transport, reliability, independent power sources, etc. Conventional air lift pumps require inlets placed at considerable depth below the water surface and function primarily in the vertical so that the multiphase mixture will be sustained as it rises. Further, air lift pumps are generally inefficient and closed pressure vessel systems are expensive and complicated. 
         [0009]    Accordingly, it would be useful to have a dewatering system that is capable of handling a large volume of fluid, capable of pumping fluid contaminated with sediment, and capable of operating without a dedicated motor with available power. 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    The present invention is directed to a dewatering system having a catch basin adapted to collect water from an area of concern and conduit to convey the collected water to an elongated discharge chamber having a muzzle at a distal end in communication with a desired outfall body and a substantially closed proximal end. The muzzle includes a first backflow prevention device to prevent backflow from the outfall body into the discharge chamber while permitting discharge from the discharge chamber via the muzzle. The conduit, being interposed between the catch basin and the discharge chamber to provide fluid communication from the catch basin to the discharge chamber includes a second backflow prevention device to ensure water communication from the catch basin solely in a direction to fill the discharge chamber. The discharge chamber further comprises a vent to enable the escape of air from the discharge chamber as water fills the discharge chamber. This vent may include a valve to prevent release of water through the vent as the discharge chamber discharges. 
         [0011]    An anchor secures the discharge chamber in a desired orientation and depth with respect to the outfall body and the catch basin. Preferably, the discharge chamber includes substantial horizontal travel for the discharged water, as described herein, enabling the water to clear the area of concern. 
         [0012]    For the purpose of discharging water form the discharge chamber, a supply of compressed air is fluidly interconnected with the proximal end of the discharge chamber. A control valve may be situated in fluid communication with the supply of compressed air for operatively controlling the flow of compressed air into the discharge chamber. Thus, actuation of the control valve releases compressed air into the proximal end of the discharge chamber to forcibly discharge water out of the discharge chamber via the muzzle and into the outfall body to dewater the area. This supply of compressed air may include an air compressor fluidly interconnected with the supply of compressed air. 
         [0013]    The discharge chamber may be configured for manual or automated discharge. Automated discharge may require a control system having sensors to measuring the level of water within the discharge chamber and a controller to actuate the control valve when the level of water within the discharge chamber is at a desired level. 
         [0014]    In many embodiments, it is contemplated that the proximal end of the discharge chamber may be positioned at a depth below the catch basin and the muzzle, such that the discharge chamber may fill by gravity drain. In some configurations, the dewatering system may include a fill pump fluidly interconnected within the conduit, configured with its input from the direction of the catch basin and its output in the direction of the discharge chamber, such that upon operation the pump will assist in filling the discharge chamber. 
         [0015]    The present invention includes a method of dewatering a surface, having the steps of providing at least one catch basin within an area adapted to collect surface water from an area, providing an elongated discharge chamber with a distal end muzzle in communication with a desired outfall body and a substantially closed proximal end, wherein the proximal end may optionally be positioned at a depth below the catch basin and the muzzle includes a first backflow prevention device to prevent backflow from the outfall body into the discharge chamber while permitting discharge out of the muzzle from the discharge chamber, providing piping or conduit between the catch basin and the discharge chamber for fluid communication from the catch basin to fill the discharge chamber, wherein a second backflow prevention device is interposed between the catch basin and the discharge chamber within the conduit to ensure water communication from the catch basin solely in a direction to fill the discharge chamber, providing a vent to the discharge chamber to enable the escape of air from the discharge chamber as water fills the discharge chamber, anchoring the discharge chamber in a desired orientation and depth with respect to the outfall body and the catch basin; and when the water in the discharge chamber reaches a desired level, releasing compressed air into the proximal end of the discharge chamber to forcibly expel the water out of the muzzle and into the outfall body to dewater the area. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0016]      FIG. 1  is a side view schematic of an embodiment of the present invention for dewatering an area behind a levee. 
           [0017]      FIG. 2  is a side view schematic of an embodiment of the present invention for dewatering an area behind a sea wall. 
           [0018]      FIG. 3  is a side view schematic of an embodiment of the present invention for dewatering an area aboard a water craft. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    The present invention is a dewatering system. The system collects surface water from an area and communicates this water to a discharge chamber, for further travel or communication to an ouffall body. When the discharge chamber is filled to a desired level, defined in part by the volume of the chamber, then compressed gas may be released into the discharge chamber to force the water out of the chamber and into the outfall body. Thus, the present invention dewaters by periodically discharging discrete units or volumes of water from a discharge chamber. 
         [0020]    The discharge chamber of the present invention may take a variety of forms. In one embodiment, the discharge chamber may be in the form of a modified wave cannon, which heretofore has been used to generate artificial waves or other recreational effects. This form of artificial wave generation technology was disclosed in U.S. Pat. No. 5,833,393 to Carnahan et al., which is hereby incorporated by reference. This technology has sometimes been referred to as a wave cannon because it is an elongated discharge chamber or barrel having a muzzle at a distal end and a substantially closed proximal end. A wave cannon is configured to generate waves when compressed air is released into the proximal end of the wave cannon, forcing water out of the muzzle and into a body of water or wave pool to create swells or waves. Because of the nature of compressed gas, wave cannons may transfer large amounts of energy while having unobtrusive or sub-grade infrastructure. 
         [0021]    Thus, one embodiment of the present invention is a dewatering system having a modified wave cannon as a discharge chamber. Of course, the present invention is not directed to creating waves, and may be adaptable to a wide variety of different configurations of discharge chambers and systems. For example, a pumping station for pumping storm water may use several substantially horizontal discharge chambers that discharge without synchronization, even though driven by a common compressed air source. Notably, the cross section of the discharge chamber of the present invention may take a wide variety of geometric shapes or forms, so long as it is effective as an elongated chamber for discharging water, having a muzzle or substantially open distal end and a substantially closed proximal end. 
         [0022]    Any number of discharge chambers may be used in the present invention, although two or three pumps may be desirable depending on the volumetric flow rate and level of reliability needed. The area of coverage, the size of the discharge tube, the frequency of discharge, volume or availability of compressed gas, and the pressure of the compressed gas will all contribute to the volumetric discharge rate. In the event that small quantities of surface water are expected, a primary discharge chamber with a single installed back up discharge chamber may be appropriate. Because of the simple design of the present invention, the discharge chamber is one of the more durable components. Thus, optionally, redundant supply lines, storage accumulators, and compressed gas systems may be more of a reliability concern than the presence of installed back up discharge chambers, which could reduce cost. In the event of a power loss, the compressed air may be provided by accumulator storage tanks or generated locally by independent emergency compressors. Preferably, automatic backup diesel engines with emergency fuel supplies may operate air compressors and generate control power; alternatively, a system may use a backup battery driven compressor, solar powered compressor, etc. 
         [0023]    Preferably, the discharge chamber is configured for the avoidance of low water volume flow in which a substantial quantity of air escapes from the discharge chamber without having forced water to discharge. It is contemplated that a large volume slug flow driven by a gas bubble formed by the released air could produce an effective discharge of water. Of course, the flow regime will depend on a variety of fluid properties, including the size and shape of the discharge chamber, the volume and pressure of the released air, and the desired flow rate. Each release of air is a discrete admission of air into the discharge chamber, in which the expansion of the air corresponds to a discrete discharge of water volume analogous to the firing of a cannon. 
         [0024]      FIG. 1  illustrates an example of the present invention. A drainage field, culvert, or body of water is selected to receive the discharge, here designated “outfall body”  10 ; this outfall body  10  is constrained by levee  50 L from flooding area  60  of the surface to be dewatered. Catch basin  30  is preferably located at a low point in the topography of area  60  and collects runoff water or any water from outfall body  10  that might have overtopped levee  50 L. In this embodiment, water collected in catch basin  30  gravity drains along conduit  32 , past drainage check valve  31 , and into discharge chamber  20 . At the distal end  20 D of discharge chamber  20  is muzzle check valve  21  (e.g., a unidirectional check or flapper valve) to prevent back flow from the outfall body  10  into discharge chamber  20 . 
         [0025]    Note that along discharge chamber  20  (i.e., moving from proximal end  20 P to distal end  20 D) there is substantial horizontal travel for the discharged water. This enables the water to clear levee  50 L, even though this example shows angle  70  or slope in the direction of distal end  20 D. Substantial horizontal travel along discharge chamber  20  may be considered for the present invention travel other than predominantly or purely vertical movement. Of course, the more vertical configurations with steeper slopes would provide less relative horizontal travel. Further, a more vertical configuration would require greater energy to discharge a unit volume of water, and thus would likely be less efficient. 
         [0026]    It is contemplated that discharge chamber  20  may be anchored underground at a desired orientation and depth with respect to the ouffall body  10  and the catch basin  30 . The distal end  20 D high point of discharge tube  20  may be vented as shown by vent  27 . Optional vent isolation valve  26  may be open for venting during filling of discharge chamber  20 , and closed during the discharge or firing of discharge chamber  20 . 
         [0027]    A supply of compressed air is fluidly interconnected with the proximal end  20 P of the discharge chamber  20 . This supply may take a variety of embodiments. For example, compressed air may be stored in accumulator  23 . When discharge chamber  20  is filled with water, compressed air may be released into a substantially closed proximal end of discharge chamber  20  by actuation of control valve  22  (i.e., preferably with vent isolation valve  26  closed). Those skilled in the art will acknowledge that water level indicators may be used within discharge chamber  20 , and that commercially available controls and actuators may be used with control valve  22  for automated operation. Compressed air facility  11  may include compressor  12  for charging of accumulator  23 . As noted above, compressor  12  may be an emergency diesel compressor, battery driven compressor, solar powered compressor, etc. 
         [0028]    Optionally, the discharge of vent  27  may be directed to a low pressure reclamation system (not shown) wherein the head of water pressure filling discharge chamber  20  may be used to establish an initial pressurization caused by air escaping from discharge chamber  20 . Such low pressure air may then be dehumidified and supplied to compressor  12  for final pressurization, as needed. 
         [0029]      FIG. 2  shows another embodiment of the present invention. In this example, outfall body  10  is separated from area  60  by seawall  50 S. Although drainage area  60  is shown below the level of outfall body  10 , the present invention is also contemplated for circumstances in which drainage area  60  may be above the level of outfall body  10 . A closing spring bias for muzzle check valve  21  may be used to enable discharge chamber  20  to fill prior to discharge, if desired. Such a design could accommodate circumstances in which the outfall body  10  water level may vary from below the level of area  60  to above the level of area  60 . Alternatively and more simply, discharge chamber  20  may simply drain by gravity into outfall body  10  when water level in outfall body  10  is below area  60 . 
         [0030]    Preferably, proximal end  20 P of discharge chamber  20  is situated below area  60  to permit gravity drainage. Although gravity filling of discharge chamber  20  is preferable, it is not required. In such alternate embodiments without gravity systems, conventional drain pumping system may be used. That configuration may be desirable as a high water level backup for use in the event of extraordinary flooding. Thus, the use of additional pumps to fill discharge chamber  20  is feasible; however, that approach may re-introduce some of the disadvantages overcome by the present invention. Because the water level over drainage area  60  may vary—certain embodiments may include discharge chambers  20  at various levels or elevations for dewatering at different locations or topographies over drainage area  60 . 
         [0031]    For the example in  FIG. 2 , water from drainage area  60  passes through surface storm drains or catch basins  30  and past drainage check valve  31  into discharge chamber  20 . As discussed above, if the distal end  20 D of discharge chamber  20  is above the level of outfall body  10  at any time (e.g., a low tide or early in a flood), and discharge chamber  20  contains water, then the water may freely pass from catch basin  30  through conduit  32  into discharge chamber  20  and then into ouffall body  10 . For embodiments with discharge chamber  20  consistently below the level of outfall body  10 , discharge chamber  20  is preferably oriented with at least a slight incline in the direction of distal end  20 D and outfall body  10 . This incline, in conjunction with vent  27 , enhances efficient filling, venting, and discharge of discharge chamber  20  into outfall body  10 . 
         [0032]    Optionally, in some environments, the present invention may include a system for hydroelectric generation of power (not shown) within the path of water flow, such as a turbine or propeller known in the art, which is driven during discharge of discharge chamber  20 . Any power generated could be stored for emergency use, possibly as control power for actuation of valves and sensors. 
         [0033]      FIG. 3  shows another embodiment of the present invention. In this example, the present invention is installed on a water craft or vessel  100 , such as a ship or submarine, in which the surrounding water may comprise ouffall body  10 . Bulkheads  50 B separate ouffall body  10  from interior spaces of vessel  100 . Anchor  40  affixes discharge chamber  20  to vessel  100  in a desired orientation. Drainage area  60  are those spaces desired to be pumped, typically bilges, which are lower areas in the inner hull (i.e., possibly excluding tanks or other bottom hull structures.) This example demonstrates gravity fill of discharge chamber  20  via catch basins  30 , via drainage check valves  31 . Optionally, discharge chamber  20  may be filed by a separate pumping system, if desired (not shown). Because of variations in orientation due to pitch, roll, or yawl of vessel  100 , it may be desirable to install multiple vents  27  along discharge chamber  20 , which would also enable a more horizontal orientation of discharge chamber  20 . Further, for marine use, muzzle check valve  21  is preferably marine quality and may include separate or redundant isolation valves or check valves. As shown, air compressor  12  may be a common compressor located remotely and serving systems in addition to the present invention. Further, accumulator  23  may be configured in a bank to provide long term capacity for the purpose of safety; dewatering of a vessel may be critically important in a severe flooding casualty. Of course, those skilled in the art will acknowledge that standard modifications for afloat use may be appropriate—such as the ability to lock out control valve  22  during certain operations of vessel  100 , redundant supporting systems, use of materials suitable for the corrosive marine environment, or use of larger air pipes at the point of connection with discharge chamber  20  to avoid freezing while compressed air expands into discharge chamber  20 , etc. 
         [0034]    Optionally, some shipboard embodiments may include an alternate mechanism (not shown) for water charging or filling of discharge chamber  20  in addition to catch basin  30 . This may be desirable if discharge chamber  20  is configured for use as an emergency propulsive force. 
         [0035]    The above examples should be considered to be exemplary embodiments, and are in no way limiting of the present invention. Thus, while the description above refers to particular embodiments, it will be understood that many modifications may be made without departing from the spirit thereof.