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This application claims benefit of U.S. Provisional Application Nos. 60/165,795, filed Nov. 16, 1999; No. 60/165,677, filed Nov. 16, 1999; and No. 60/200,460, filed Apr. 28, 2000, the entirety of the disclosures of the foregoing applications being incorporated herein be reference thereto. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates generally to a reduction system for removing soil in order to expose underground utilities (such as electrical and cable services, water and sewage services, etc.) and also for removing other materials from the ground or other surfaces for cleanup or remediation purposes. 
     With the increased use of underground utilities, it has become more critical to locate and verify the placement of buried utilities before installation of additional underground utilities or before other excavation or digging work is performed. Conventional digging and excavation methods such as shovels, post hole diggers, powered excavators, backhoes, etc., may be limited in their use in locating buried utilities as they may tend to cut, break, or otherwise damage the utilities during use of such digging devices. 
     Electronic devices are known which can be used to locate buried utilities with a certain degree of accuracy, one of such devices being the VERIFIER®, manufactured by McLaughlin Manufacturing Company of Greenville, S.C. In using this device, an operator walks on the ground while holding the locating device, which signals when it finds a buried utility. The operator can then mark the ground at that point, but ordinarily, an actual viewing of the buried utility is required for confirmation. This requires digging up the soil manually, such as with a shovel or post hole digger, or using some powered digging means. 
     Devices have been developed which create holes in the ground to non-destructively expose and allow the actual bare underground utilities to be viewed. One design uses high pressure air delivered through a reduction tool, or wand, in order to loosen soil to form a hole, and includes a vacuum system to vacuum away the dirt as the dirt is loosened. Another system uses high pressure water delivered by a wand to soften the soil and create a soil/water slurry mixture. The wand is provided with a vacuum system for vacuuming the slurry away. 
     In addition to boring holes in the ground in a non-destructive manner, these devices may also be used for removing drilling mud, such as bentonite drilling fluid, which may leak out to the ground surface during well installations or other excavation operations. Otherwise, the bentonite could remain as an unsightly and undesirable coating on lawns and other ground coverings. Apart from vacuuming bentonite, the devices could be used to vacuum mud or other spoil from the ground, which could be byproducts of excavation or drilling operations, or, perhaps, flooding or spills. 
     One such device which uses water and a vacuum system is disclosed in U.S. Pat. No. 5,295,317, issued to Perrott. U.S. Pat. No. 5,408,766, issued to Pobihushchy, discloses an excavator having a cutting tool pipe with nozzles for delivering high pressure water. The vacuum is drawn through a hose, with the water and displaced soil being drawn away into a holding tank. 
     U.S. Pat. No. 5,140,759, issued Artzberger, discloses a pneumatic excavator having nozzles associated with a housing and conduit. Another pressurized air device is disclosed in U.S. Pat. No. 4,936,031, issued to Briggs, et al., which discloses an excavator having air nozzles extending downwardly from a digging head, which rotates during use. A suction unit is also provided. 
     While the foregoing designs are known, there still exists a need for a device having improved reduction capabilities. 
     SUMMARY OF THE INVENTION 
     It is, therefore, the principal object of this invention to provide a reduction system. 
     Another object of the present invention is to provide a soil reduction system for excavating or removing soil in order to dig a hole. 
     Another object of the present invention is to provide a reduction system for moving materials such as snow, mud, grain, from one location to another. 
     Yet another object of the present invention is to provide a reduction system for use in rescue operations for removing persons trapped or buried beneath soil, snow, mud, grain, or some other substance. 
     Still another object of the present invention is to provide a reduction system for removing materials from the surface of the ground. 
     Another object of the present invention is to provide a reduction system having an improved fluid nozzle configuration. 
     Still another object of the present invention is to provide a reduction system having means for automatically cleaning a holding tank. 
     Yet another object of the present invention is to provide a reduction system having a reduction tool which can be readily extended in length. 
     A further object of the present invention is to provide a reduction system having a reduction tool with control means associated with the handle for controlling nozzle fluid flow and/or vacuuming action of the reduction tool. 
     Another object of the present invention is to provide a reduction system having nozzles in a reduction tool configured for providing a spiral cutting action. 
     Yet another object of the present invention is to provide a reduction system having an automatic shut-off feature upon filling of a slurry, or spoil, accumulation tank. 
     Yet another object of the present invention is to provide a reduction system having an automatic shut-off feature upon the level of water in a fluid supply tank falling below a predetermined level. 
     A further object of the present invention is to provide a method for removing soil or other matter from ground surface. 
     Another object of the present invention is to provide a method for cleaning an accumulation tank of a reduction device. 
     Generally, the present invention includes a reduction system using water pressure and vacuum excavation and includes a water supply tank, water pump, vacuum pump, slurry collection tank, means for tilting the collection tank, handheld reduction tool, and drive means. 
     The reduction tool, or wand, is used to deliver high pressure fluid, such as water, to the ground in order to loosen soil directly in front of the tool. The tool includes diametrically opposed nozzles which are angled with respect to one another such that pressurized water delivered from the nozzles is directed in a fashion to slice the ground in a generally spiral or helical fashion as the tool is pressed downward into the ground. 
     As the soil is loosened by the pressurized water delivered from the nozzles, the loosened soil is sucked away to form a hole in the ground, and such loosened soil (a slurry when mixed with the water) passes upwardly through the tool in a vacuum air-flow created by the vacuum pump. This slurry is ultimately deposited in the slurry collection tank. 
     To assist in the suctioning of the soil/water, or slurry, mixture from the hole, the tool is provided with air inlets which allow for the suction air-flow to sweep around the dirt and hole being cut with the tool. 
     The present invention also includes a single water line extending the length of the tool and terminating in a generally C-shaped manifold, to which the nozzles are attached. The C-shaped manifold is located on the interior of the reduction tool rather than on the exterior, thereby providing protection to the manifold from damage as the tool is being used. 
     A control valve is incorporated into a handle provided on the reduction tool, and the control valve is used to activate or deactivate the pressurized water nozzles as necessary. 
     The end of the reduction tool opposite the end having the nozzles is provided with connection means, such as quick release clamps, or banjo clips, which allow additional tool extension sections to be attached to effectively lengthen the tool, to thereby allow for digging deeper holes. 
     The reduction system of the present invention also includes an automatic tank clean out feature provided in the slurry collection tank. The slurry collection tank is used for storing the slurry, or spoil, or other material vacuumed up by the tool. When the slurry collection tank becomes full, an automatic system is provided which automatically shuts down the vacuum system. This prevents the slurry mixture from being drawn into the vacuum pump. 
     When it becomes necessary to empty the slurry collection tank, the liquid contents can be drained through a valve, such as a gate valve provided in the door of the tank. However, in order to remove solids which remain in the tank, a series of nozzles, such as fan nozzles, are provided which are connected to a water supply pipe running axially through the tank. These fan nozzles can then be actuated to deliver high pressure water to clean the tank, without requiring the operator to use a water hose or to resort to manual cleaning. 
     The axially running pipe includes a threaded male end which is received within a female fitting attached to a screw-down door handle provided on a door for the collection tank. The axial tube thus performs not only as a conduit for delivering water to the fan nozzles used to clean the tank, but also acts as a structural member against which the collection tank door is pulled when the door handle is turned, to an adjustable preset seat, for tightly sealing the door. 
     A reservoir water tank is provided with the system as a reservoir for supplying water to the nozzles. 
     The reduction system of the present invention can also be used for material handling purposes for transporting granular or particular matter, such as sand, soil, grain, or other substance from one location to another, namely, the accumulation tank. In such operations, the reduction system may be used with or without the water nozzle feature discussed above. 
     The reduction system of the present invention may also find use in rescue operations for buried or trapped persons. For example, the system could potentially be used for removing snow in order to locate or provide breathing passages for persons buried by an avalanche. It could also be used to remove or assist persons buried by earthquakes, landslides, mudslides, in grain elevators or in other farm or industrial situations. Additionally, it could be used to recover the bodies in a generally non-destructive manner of those who have perished in the foregoing situations. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing, as well as other objects of the present invention, will be further apparent from the following detailed description of the preferred embodiment of the invention, when taken together with the accompanying specification and the drawings, in which: 
     FIG. 1 is a perspective view of the reduction system constructed in accordance with the present invention; 
     FIG. 2 is a side elevational view of a reduction system constructed in accordance with the present invention; 
     FIG. 3 is a perspective view of a reduction tool constructed in accordance with the present invention; 
     FIG. 4 is a sectional view taken along lines  4 — 4  of the reduction tool shown in FIG. 3; 
     FIG. 5 is a partial perspective view of the reduction tool in use digging a hole; 
     FIG. 6 is a side elevational view of a slurry collection tank used in the reduction system constructed in accordance with the present invention; 
     FIG. 7 is sectional view of a door for the slurry collection tank taken along lines  7 — 7  in FIG. 6; 
     FIG. 8 is sectional elevational view of the slurry collection tank taken along lines  8 — 8  in FIG. 6; 
     FIG. 9 is an end view of the reduction system, showing a water supply tank constructed in accordance with the present invention; 
     FIG. 10 is a partial side elevational view of drive means for the reduction system; 
     FIG. 11 is a schematic view of the hydraulic, water, and vacuum systems of the reduction system; and 
     FIG. 12 is a perspective view of an alternate embodiment of a reduction tool constructed in accordance with the present invention having a vacuum head. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The accompanying drawings and the description which follows set forth this invention in its preferred embodiment. However, it is contemplated that persons generally familiar with soil reduction equipment will be able to apply the novel characteristics of the structures illustrated and described herein in other contexts by modification of certain details. Accordingly, the drawings and description are not to be taken as restrictive on the scope of this invention, but are to be understood as broad and general teachings. 
     Referring now to the drawings in detail, wherein like reference characters represent like elements or features throughout the various views, the reduction system of the present invention is indicated generally in the figures by reference character  10 . 
     Turning to FIG. 1, reduction system  10  includes a trailer, generally T, on which a water reservoir tank, generally W, is mounted. Water reservoir W is connected to a water pump, generally P, which is driven by a motor, generally M. Motor M also drives a vacuum pump, generally V (FIG. 6) and provides through its electrical system electrical power for driving an electric hydraulic pump, generally H (FIG.  11 ). Vacuum pump V and water pump P are both connected to a reduction tool, generally R, which is the actual remediation tool worked by an operator, generally (FIG.  1 ). Also mounted on trailer T is a slurry, or spoil, collection tank, generally C, which is also connected to vacuum pump V, with vacuum pump V drawing a vacuum through collection tank C and reduction tool R during use of reduction system  10 . 
     Trailer T includes four wheels  12  and a draw bar  14  (FIG. 2) and also platform, generally  18 , on which reduction system  10  is carried. Water tank W is carried on a forward end of trailer T, and slurry, or spoil, collection tank C is carried on the rear end thereof. Disposed between tanks W and C is motor M, which is preferably gas or diesel engine, although it is to be understood that an electric motor or other motive means could also be used. Preferably, motor M is a thirty horsepower diesel engine, such as manufactured by Kubota (Model No. V1505), or a gas engine such as a Kohler (Model Command PRO CH25S), which is a twenty-five horsepower gasoline engine. Other engines, of course, could be used instead. Motor M drives water pump P via a belt (not shown), and water pump P includes a low pressure inlet side  22  and a high pressure outlet side  24 . 
     As shown in FIG. 11, water tank W is connected to the low pressure side of water pump P via a hose  28 . Water tank W includes an outlet  30  through which water therefrom first flows through a strainer  32 , from a valve  34 , then to a check valve  36 , and then on through the hose  28  to the low pressure side of water pump P. The high pressure side of water pump P includes a hose  38  connected to a filter  48  then to a pressure relief and bypass valve  42 . In line between the high pressure outlet of the water pump and the valve  42  is a tee  44  with valve  45  connecting the high pressure line to clean out nozzles, generally  46 , as shown in FIGS. 6,  8 , and  11 , which will be discussed in more detail below. 
     The high pressure line then goes to a filter  48  and on to the pressure relief and bypass unloader valve  42  which is preferably a General Pump Model YUZ140. A return line  50  is connected to valve  42  and to water tank W for returning water at a low pressure to tank W when a predetermined pressure is exceeded in the valve  42 . This causes water to fully bypass to tank W, or in the event pressurized water, or other fluid as may be needed, is not yet up to a desired pressure, such fluid is returned to the tank W until the predetermined pressure is achieved in the valve  42 . A hose  52  is connected to the output of the valve  42  which leads to the reduction tool R. A valve control  53  at the handle, generally  55 , of the reduction tool is provided which allows the operator to selectively actuate the valve  53  to deliver water to a conduit  54  (FIGS. 1,  3 ,  5 , and  11 ) attached to the exterior of an elongated pipe  56  which extends the length of the reduction tool. 
     The water pump P could be any of a variety of pumps, but preferably delivers between 3,000 and 4,000 pounds per square inch, preferably at a flow rate of approximately four gallons per minute, one suitable pump is manufactured by General Pump (Model No. TS1511). 
     The reduction tool R includes the handle  55  noted above for grasping by the operator during use of the tool. The handle includes a connector  58  (FIG.  3 ), such as a “banjo” connector, for connecting a central vacuum passage  60  (FIG.  4 ), which extends the length of the tool R, to a vacuum source. This is accomplished by attaching one end of vacuum hose  62  to the handle, and the other end of the hose  62  to the collection tank C at a collection tank inlet  64  (FIG.  1 ). Other connection means could also be used instead of banjo connectors, such as clamps, clips, threaded ends on pipe  56  and handle  55 , etc., none of these being shown. 
     At the inlet end  66  of the reduction tool, which is opposite the end where the vacuum hose is connected, a fluid manifold  68  (FIG. 4) is provided to which a plurality of nozzles, generally N, are connected. The manifold  68  is connected to the water conduit  54  running the length of the reduction tool. As shown in FIGS. 4 and 5, an important feature of the reduction tool is that the nozzles N are angled with respect to one another. In one preferred embodiment, four such nozzles are used, and two of the nozzles  72 ,  74  are directed radially inwardly at approximately 45 degrees from vertical. Such an orientation of the nozzles  72 ,  74  produces a spiral cutting action in the soil as the reduction tool is used. This spiral cutting action breaks the soil up sufficiently to minimize clogging of the soil within the reduction tool vacuum passage and/or the vacuum hose leading to the collection tank C with large chunks of soil. 
     Another important feature of the reduction tool is provision of a plurality of air inlets  76  in the pipe  56  forming the vacuum passage  60 , these inlets  76  allowing air to enter into the vacuum passage adjacent the inlet of the reduction tool. This improves the swirling action of the suction provided by the reduction tool and the speed by which tool R digs, such swirling action being enhanced by the angled placement of the nozzles  72 ,  74  and contributing to the spiral cutting action of the reduction tool as it is used. 
     The downward cutting action of the reduction tool is also enhanced by the two nozzles  82 ,  84  which generally point vertically downwardly and which, in combination with the other two angled nozzles  72 ,  74 , allow for soil to be removed not only above a buried utility, but in certain cases, allows for soil to be removed from around the entire periphery of a buried cable or pipe. In other words, the soil is removed above such utility, from around the sides of the utility, and beneath the utility. This can be useful for further verifying the precise utility, and also, if necessary to make repairs or to tie into such utility. 
     Reduction tool R could include an additional control for controlling the vacuum feature of the tool. This could allow remote control  85  of the vacuum system, and could comprise an electrical switch and/or a vacuum or pneumatic switch, or perhaps, a wireless switch to control the vacuum action by allowing the vacuum to be shut off, or otherwise modulated from the handle above the reduction tool. 
     A wireless remote control system  88  for controlling the idle speed of motor M is also part of the invention. As shown in FIG. 11, the speed of motor M can be varied between high and low by a keypad transmitter  90 , which transmits motor speed control to receiver  92  connected to the throttle of motor M. 
     As shown in FIG. 12, reduction tool R may also include attachments, such as a vacuum device  93  having a slotted vacuum head  94  for allowing removal of drilling mud and non-hazardous fluid from the ground surface. Additionally, the effective length of the reduction tool R can be readily extended by adding additional sections of pipe  95 . These sections are connected to the handle portion with use of releasable clips, such as banjo clips  98  (FIG.  8 ), or through a threaded connection, clamps, or some other suitable connection means (not shown). 
     Turning now to FIGS. 6 and 11, the vacuum system of the present invention includes a vacuum pump V, preferably a positive displacement type such as the type used as a supercharger on diesel trucks. One such pump is a Tuthill blower (Model 4009-46R3). The vacuum pump is preferably driven by the motor M by a belt (not shown), and the intake  102  of the vacuum pump preferably leads to a vacuum relief device  104 , such as a Kunkle valve (Model 215V-H01AQE), which controls the maximum negative pressure of vacuum to be pulled by the pump. The negative pressure range is preferably between ten inches and fifteen inches of Hg. Downstream of the pressure relief valve is a filter  106 , which can be a paper filter such as a Fleet Guard brand filter, and then downstream from the filter  106 , the vacuum is connected to the exhaust outlet  108  of the collection tank, as shown in FIGS. 1,  2 ,  6 ,  8  and  11 . The exhaust side of the vacuum pump includes a conduit  110  leading to a silencer  112 , such as manufactured by Phillips and Timroe Industries. From the silencer  112 , the exhaust is vented to atmosphere. 
     The vacuum provided by the vacuum pump produces a vacuum in the collection tank, which in turn draws a vacuum through the inlet  113  of collection tank. When not closed by a plug  114 , the inlet may be hooked up to the hose  62  leading to the reduction tool R for drawing vacuum through the reduction tool together with soil and water produced from digging a hole, such as in a slurry mixture, or water and/or drilling mud, bentonite, or other materials to be vacuumed. 
     Since it would be undesirable to draw dirt or other particular matter into the vacuum pump, a baffle system is provided within collection tank C to separate soil and other material from the soil, water, and other material from the vacuum air flow received from the reduction tool. As shown in FIG. 6, air drawn in through the inlet  113  of the collection tank is first drawn upwardly, and dirt, rocks, and other debris in the flow hit a baffle  118  and expend energy, thereby falling to the bottom portion of the collection tank. Smaller particles continue to be carried by the flow towards the front of the tank, and downwardly across the bottom of the tank back towards the rear  120  of the tank. Debris that does not fall out by this point may be carried upwardly, but may also impact a V-shaped baffle  122  (FIG.  7 ), provided on the discharge door  124  of the tank. The discharge door  124  is hinged to the top of the tank by a hinge  126  and swings open to allow cleaning the tank, as will be discussed in more detail below. 
     The vacuum air stream, after contacting the V-shaped baffle  122  continues upwardly and impacts and is deflected by an upper baffle  128  and then further impacts and is further deflected by a second upper baffle  130 , each time causing additional particles or other materials constrained in the air flow to become trapped at these baffles. Finally, the vacuum air flow exits the outlet  108  of the collection tank and passes through the filter  106  and on to the vacuum pump, as discussed above. 
     Collection tank C includes means for emptying its contents. Hydraulic cylinders  132  (FIG. 2) are provided for tilting the forward end  134  of the tank upwardly in order to cause the contents to run towards the back door  124 . After opening of the back door, the contents may then be discharged therefrom. 
     A problem may arise, however, in cleaning out the solids deposited in the base of collection tank C. Prior systems have required manual cleaning of the tank with tools and/or a water hose, and the present invention includes an important automatic tank cleaning feature. Running the length of the tank C is a nozzle tube  140  supported by hanger  141  (FIG. 8) which includes a plurality of fan-shaped nozzles  46  for directing high pressure water about the tank, and particularly towards the base of the tank. These nozzles  46  are actuated by turning the valve  45 , which causes high pressure water delivered by the water pump to be delivered to the nozzles for producing a vigorous cleaning action to the tank. Preferably, even when the nozzles  46  are not being used for cleaning, a small amount of water is allowed to continuously drip through the nozzles to pressurize them in order to prevent dirt and slurry delivered to the tank during the reduction operation from entering and clogging the nozzles. 
     Although not shown, the nozzles could be provided with check valves to prevent the soil/water mixture, or slurry, from entering the nozzles during transport of device  10  or the vacuuming operation to thereby prevent clogging thereof. Or, it is anticipated that “gland” type nozzles could also be used which seal themselves when not in use. This, again, prevents or minimizes clogging of the nozzles. Additionally, mechanical flappers (not shown) could be used to cover the exit of the nozzles when not in use, the flappers being blown to the side out of the way by the force of the nozzles when actuated. 
     The nozzle tube  140 , apart from being a conduit for delivering water to the high pressure nozzles used for cleaning tank C, is also a structural member. The nozzle tube includes a threaded male portion  142  (FIG. 6) on the end thereof adjacent the back door  124  of the collection tank. When the door is to be shut, and the collection tank sealed, a screw-down type handle  146  mounted in the door is turned, and the screw-down handle includes an outwardly projecting threaded female portion  148  (FIG. 6) which mates with the male portion as the handle is turned, thus tightly pulling the door to the open rim  150  of the collection tank, thereby sealing the tank. Actuation of the vacuum pump further assists the sealing of the door against the tank opening. Note the door also includes a sight glass  152  to allow for visual observation of the interior of the tank. 
     Another feature of the present invention is the automatic shutoff system provided within the collection tank. A float switch  154  (FIG. 8) is provided in the tank connected to a float  156 . This float switch normally hangs downwardly until the level of slurry in the tank rises to a level which causes the float switch to begin to float and move upwardly. Once the float switch moves upwardly by a predetermined amount, it causes, through action of the rod connected to the float switch, float switch  154  to activate to shut off the vacuum system. This prevents the slurry level from becoming so high that it is actually drawn upwardly through the outlet of the tank and into the vacuum pump. 
     Although not shown, instead of or in addition to the nozzle tank cleaning system discussed above, the collection tank could be provided with a hydrostatic perforated plate on the bottom of the tank. This plate would include numerous holes through which fluid or air could be pumped upwardly. This upward pressurized flow could be used to lift sediment from the bottom of the tank, and as the tank is tilted upwardly during the cleaning operation, it is anticipated that such hydrostatic pressure could be used to loosen up and perhaps levitate the sediment for dumping from the tank. 
     The door to the collection tank also includes a gate valve  160  for draining the liquid portion of the slurry through a drain  161  in the back door  124 , without requiring the door  124  to be open. The gate valve may also be used to introduce air into the tank in order to reduce the vacuum within the tank by a sufficient degree such that the door may be opened. 
     The hydraulic cylinders  132  used to tilt the tank are powered by an electric hydraulic motor, generally H (FIG.  11 ), having a hydraulic reservoir  164 , the motor being driven by the electrical system of the motor M. An additional hydraulic pump  168  can be mechanically mounted to the motor M to be driven by motor M. As shown in FIG. 11, the hydraulic pump  168  includes its own hydraulic reservoir  170  and can be a conventional tractor hydraulic pump such as manufactured by Kubota. The output high pressure line of the hydraulic pump, which preferably delivers between 5.8 and 6 gallons per minute, is connected to a pressure relief valve  171  and also a control valve  172  for controlling flow of hydraulic fluid through the line. A pressure gauge  174  may also be provided between the pressure relief valve and the control valve. Control valve  172  includes a knob (not shown) for activating same. From the control valve, a line leads to a quick disconnect coupling  178  (FIGS.  1  and  2 ), which is mounted within the frame of the trailer. This quick disconnect provides a high pressure source of hydraulic fluid for powering auxiliary tools, such as perhaps pavement saws, breakers, or other devices which may be used in connection with a reduction system  10 . A hydraulic return line  180  is also provided on the trailer, and downstream of the return line inlet is a filter  182  which filters the hydraulic fluid before returning it to the hydraulic reservoir. 
     An antifreeze system, generally  184  (FIGS.  1  and  9 ), is provided for preventing freezing of the water pump and water system. When the pump is to be left unused in cold weather, the pump may be used to draw antifreeze from the reservoir. Preferably, such antifreeze is nontoxic, and environmentally friendly. 
     To use reduction system  10 , water is added to water tank W, and the valve  34  is opened to allow water flow to the water pump. The motor M is powered up, and water pressure is allowed to build in the system. The reduction tool R is connected to the collection tank C with the vacuum hose  62 , and water line  184  is also connected to the reduction tool. A hose reel  188  is provided for paying out water line  184  to the reduction tool during use. 
     As the tool R is used, it is pressed downwardly into the ground in order to dig a hole. For larger diameter holes, the tool R is moved in a generally circular manner as it is pressed downwardly. Slurry will begin to accumulate in the collection tank C as the tool R is used. Once the job is finished, or when the collection tank is full, the engine is set to a low idle to maintain a vacuum in the tank. This allows the door handle to be turned such that the female threaded member is no longer in threading engagement with the male member, the vacuum pressure continuing to hold the door closed. The engine can then be shut down and then air enters the tank through the vacuum pump or other openings, thereby pressurizing the tank and allowing the door to be opened. 
     In certain situations, for example in rescue work or for transporting loose material (such as sand, snow, or grain), tool R can be used without the nozzles N being activated. Operation of tool R would be similar as with normal excavation, with tool R being pressed downwardly in the material to be removed by the operator. 
     The present invention also includes a vacuum pressure switch and relay (not shown) provided in connection with the tank C which senses the vacuum in tank C, and which prevents tank C from being raised for dumping purposes until the vacuum has dropped low enough in the tank for the door  124  to be opened. Once the vacuum in the tank has diminished to the point that door  124  may be opened, tank C may be elevated for dumping purposes. This prevents slurry contained in tank C from being pushed up into filter  106  should door  124  be open, if a vacuum were still present in tank C, and in particular, in the upper baffled chamber, generally  208 , of tank C. 
     A control panel  200  provides vacuum and water pressure readouts and also controls for motor M. Also, lights  202  are provided on system  10  for allowing use at night or in low light conditions. An auxiliary spray wand  204  is provided which can be attached to high pressure water line  184  for allowing localized cleaning of tank C or other items. 
     While preferred embodiments of the invention have been described using specific terms, such description is for present illustrative purposes only, and it is to be understood that changes and variations to such embodiments, including but not limited to the substitution of equivalent features or parts, and the reversal of various features thereof, may be practiced by those of ordinary skill in the art without departing from the spirit or scope of the following claims.

Summary:
A reduction system using water pressure and vacuum excavation and including a water supply tank, water pump, vacuum pump, slurry collection tank, a system for tilting the collection tank, handheld reduction tool, and a drive system. The reduction tool, or wand, is used to deliver high pressure fluid, such as water, to the ground in order to loosen soil directly in front of the tool. The tool includes diametrically opposed nozzles which are angled with respect to one another such that pressurized water delivered from the nozzles is directed in a fashion to slice the ground in a generally spiral or helical fashion as the tool is pressed downward into the ground. As the soil is loosened by the pressurized water delivered from the nozzles, the loosened soil is sucked away to form a hole in the ground, and such loosened soil (a slurry when mixed with the water) passes upwardly through the tool in a vacuum air-flow created by the vacuum pump and is deposited in the slurry collection tank.