Patent Publication Number: US-2021189685-A1

Title: Collection tank

Description:
CLAIM OF PRIORITY 
     This application is a continuation of U.S. application Ser. No. 17/087,440, filed Nov. 2, 2020, which is a continuation of U.S. application Ser. No. 16/786,903, filed Feb. 10, 2020 (now U.S. Pat. No. 10,844,575), which is a continuation of U.S. application Ser. No. 15/018,475, filed Feb. 8, 2016 (now U.S. Pat. No. 10,563,375), which is a continuation of U.S. application Ser. No. 14/266,354, filed Apr. 30, 2014 (now U.S. Pat. No. 9,260,049), which is a continuation of U.S. application Ser. No. 13/751,987, filed Jan. 28, 2013 (now U.S. Pat. No. 8,925,753), which is a continuation of U.S. application Ser. No. 12/979,114, filed Dec. 27, 2010 (now U.S. Pat. No. 8,360,260), which is a continuation of U.S. application Ser. No. 12/855,478, filed Aug. 12, 2010 (now abandoned), which is a continuation of U.S. application Ser. No. 11/544,428, filed Oct. 6, 2006 (now U.S. Pat. No. 7,837,050), the entire disclosure of each of which is incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to a reduction system for removing soil to expose underground utilities (such as electrical and cable services, water and sewage services, etc.), and more particularly to an improved vacuum tank for use with such system. 
     BACKGROUND OF THE INVENTION 
     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, and backhoes may be limited in their use in locating buried utilities as they may tend to cut, break, or otherwise damage the lines during use. 
     Devices have been previously developed to create holes in the ground to non-destructively expose underground utilities to view. One design uses high pressure air delivered through a tool to loosen soil and a vacuum system to vacuum away the dirt after it is loosened to form a hole. Another system uses high pressure water delivered by a tool to soften the soil and create a soil/water slurry mixture. The tool is connected with a vacuum system for vacuuming the slurry away into a collection tank. The tank may then be emptied by opening a door on the tank. 
     Prior art vacuum systems are provided with a tank having a manually closing door that is locked in a closed position by latches, locks or other suitable locking mechanisms. Such devices rely on an operator to apply the proper amount of force to ensure that a tight vacuum seal is created between an outer periphery of the door and the edge of the tank. However, if the locking force is applied at two opposing edges of the door or to a single point around the periphery of the door, then the closing force is greatest at the point where the door is locked closed. In an example where the locking points are positioned at 9 o&#39;clock and 3 o&#39;clock on the door, the greatest closing force occurs at 9 and 3 o&#39;clock with the least closing force occurring at 12 and 6 o&#39;clock. That is, as you move away from the locking points, the closing force on the periphery of the door begins to decrease. While a vacuum seal may be created, it cannot always be guaranteed especially if the door is warped. 
     SUMMARY OF THE INVENTION 
     The present invention recognizes and addresses disadvantages of prior art constructions and methods, and it is an object of the present invention to provide a collection tank for use in a vacuum operated earth reduction system, the collection tank comprising a closed first end, an open second end defining a tank sealing flange and a body extending between the closed first end and the open second end. An internal chamber defined by the body, the closed first end and the open second end has a door coupled to the open second end and is configured to releasably seal the open second end. An automated door closer is coupled to a center of the door, wherein the automated door closer provides a closing force at the center of the door so that the closing force is equally distributed about a periphery of the door to seal the door against the tank sealing flange. 
     In other embodiments, the automated door closer further comprises at least one hydraulic cylinder having a piston rod in driving engagement with one of said first and second linkage assemblies, said at least one hydraulic cylinder being configured to move said door between said open first position and said closed second position. 
     In yet another embodiment, a collection tank for use in a vacuum operated earth reduction system comprises a closed first end, an open second end defining a tank sealing flange and a body extending between the closed first end and the open second end. A door is moveably coupled to the tank open second end and defines a sealing flange about a periphery thereof. The door is configured to releasably seal the tank open second end. An automated door closer has a cross bar rigidly attached to a center of the door, the cross bar having a first end and a second end. A first linkage assembly having a first end is threadedly coupled to the cross bar first end and a second end is coupled to the body. A second linkage assembly having a first end is threadedly coupled to the cross bar second end and a second end is coupled to the body. The threaded connection between the first linkage assembly first end and the cross bar first end and the threaded connection between the second linkage assembly first end and the cross bar second end may be adjusted to change a closing force applied to the center of the door. 
     In other embodiments, the door may have a generally circular-shaped door panel having an outer circumference. Additionally, the generally circular-shaped door panel may be dome-shaped. In yet other embodiments, the door is biased into the closed second position. An in some embodiments, the automated door closer may be remotely actuated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the present invention, including the best mode thereof directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: 
         FIG. 1  is a perspective view of a prior art vacuum and backfill system; 
         FIG. 2  is a perspective view of a prior art key hole drill for use with the drilling and backfill system of  FIG. 1 ; 
         FIG. 3  is a perspective view of an earth reduction tool in accordance with an embodiment of the present invention; 
         FIG. 4  is bottom perspective view of the earth reduction tool shown in  FIG. 3 ; 
         FIG. 5  is a partial exploded perspective view of the earth reduction tool of  FIG. 4 ; 
         FIG. 6  is partial perspective view of the earth reduction tool of  FIG. 3  in use digging a hole; 
         FIG. 7  is a side plan view of the earth reduction tool of  FIG. 3 ; 
         FIG. 8  is a top plan view of the earth reduction tool of  FIG. 3 ; 
         FIG. 9  is a bottom plan view of the earth reduction tool of  FIG. 3 ; 
         FIG. 10  is a side section view of the earth reduction tool of  FIG. 8  taken along lines  10 - 10 ; 
         FIG. 11  is a perspective view of the reduction tool of  FIG. 3  in use digging the hole; 
         FIG. 12  is a perspective view of an earth reduction tool in accordance with an embodiment of the present invention in operation; 
         FIG. 13  is a bottom partial perspective view of the earth reduction tool shown in  FIG. 12 ; 
         FIG. 14  is a top partial perspective view of the earth reduction tool of  FIG. 12 ; 
         FIG. 15  is a bottom plan view of the earth reduction tool of  FIG. 12 ; 
         FIG. 16  is a top plan view of the earth reduction tool of  FIGS. 11 and 12  shown with additional extensions; 
         FIG. 17  is side plan view of the earth reduction tool of  FIGS. 11 and 12  in use digging a hole; 
         FIG. 18  is a perspective view of the earth reduction tool of  FIG. 12  in use digging a hole; 
         FIG. 19  is a perspective view of the drilling and backfill system of  FIG. 1 , showing the hole being backfilled; 
         FIG. 20  is a perspective view of the drilling and backfill system of  FIG. 1 , showing the hole being tamped; 
         FIG. 21  is a schematic view of the hydraulic, electric, water, and vacuum systems of the drilling and backfill system of  FIG. 1 ; 
         FIG. 22  is a left side perspective view of a tank in accordance with an embodiment of the present invention in operation; 
         FIG. 23  is a right side partial exploded perspective view of the tank of  FIG. 22 ; 
         FIG. 24  is a left side partial exploded perspective view of the tank of  FIG. 22 ; 
         FIG. 25  is a right side perspective view of the tank of  FIG. 22 , shown in the open position; 
         FIG. 26  is a left side partial perspective view of the tank of  FIG. 22 , shown in the open position; and 
         FIG. 27  is a left side elevation view of the tank of  FIG. 22 , shown in the closed position. 
     
    
    
     Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to presently preferred embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope and spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
     Referring to  FIG. 1 , a drilling and backfill system  10  generally includes a water reservoir tank  12 , a collection tank  14 , a motor  16 , a drilling apparatus  18 , and back fill reservoirs  20  and  22 , all mounted on a mobile chassis  24 , which is, in this embodiment, in the form of a trailer. Trailer  24  includes four wheels  38  (only three of which are shown in  FIG. 1 ) and a draw bar and hitch  40 . Drilling and backfill system  10  generally mounts on a platform  42 , which is part of trailer  24 . It should be understood that while drill and backfill system  10  is illustrated mounted on a trailer having a platform, the system may also be mounted on the chassis of a vehicle such as a truck or car. Further, a chassis may comprise any frame, platform or bed to which the system components may be mounted and that can be moved by a motorized vehicle such as a car, truck, or skid steer. It should be understood that the components of the system may be either directly mounted to the chassis or indirectly mounted to the chassis through connections with other system components. 
     The connection of the various components of system  10  is best illustrated in  FIG. 21 . Referring also to  FIG. 1 , motor  16  is mounted on a forward end of trailer  24 , provides electricity to power two electric hydraulic pumps  30  and  172  ( FIG. 21 ), and drives both a water pump  26  ( FIG. 21 ) and a vacuum pump  28  ( FIG. 21 ) by belts (not shown). Motor  16  is preferably a gas or diesel engine, although it should be understood that an electric motor or other motive means could also be used. In one preferred embodiment, motor  16  is a thirty horsepower diesel engine, such as Model No. V1505 manufactured by Kubota Engine division of Japan, or a twenty-five horsepower gasoline engine such as Model Command PRO CH25S manufactured by Kohler Engines. The speed of motor  16  may be varied between high and low by a wireless keypad transmitter  108  that transmits motor speed control to a receiver  110  connected to the throttle of motor  16 . 
     The water system will now be described with reference to  FIG. 21 . Water reservoir tank  12  connects to water pump  26 , which includes a low pressure inlet  44  and a high pressure outlet  46 . In the illustrated embodiment, water pump  26  can be any of a variety of suitable pumps that delivers between 3,000 and 4,000 lbs/in2 at a flow rate of approximately five gallons per minute. In one preferred embodiment, water pump  26  is a Model No. TS2021 pump manufactured by General Pump. Water tank  12  includes an outlet  50  that connects to a strainer  52  through a valve  54 . The output of strainer  52  connects to the low pressure side of water pump  26  via a hose  48 . A check valve  56  is placed inline intermediate strainer  52  and low pressure inlet  44 . High pressure outlet  46  connects to a filter  58  and then to a pressure relief and bypass valve  60 . In one preferred embodiment, pressure relief and bypass valve  60  is a Model YUZ140 valve manufactured by General Pump. 
     A “T”  62  and a valve  64 , located intermediate valve  60  and filter  58 , connect the high pressure output  46  to a plurality of clean out nozzles  66  mounted in collection tank  14  to clean the tank&#39;s interior. A return line  68  connects a low pressure port  69  of valve  60  to water tank  12 . When a predetermined water pressure is exceeded in valve  60 , water is diverted through low port  69  and line  68  to tank  12 . A hose  70 , stored on a hose reel  73  ( FIG. 1 ), connects an output port  72  of valve  60  to a valve  74  on a digging tool  32  ( FIG. 3 ). A valve control  76  ( FIG. 3 ) at a handle  78  of digging tool  32  provides the operator with a means to selectively actuate valve  74  on digging tool  32 . The valve delivers a high pressure stream of water through a conduit  80  ( FIGS. 3, 5, 7, and 21 ) attached to the exterior of an elongated pipe  82  that extends the length of digging tool  32 . 
     Referring to  FIG. 3 , digging tool  32  includes handle  78  for an operator  34  ( FIG. 11 ) to grasp during use of the tool, a head  93  and an elongated pipe  82  that connects the handle to the head. A connector  84 , such as a “banjo” type connector located proximate to handle  78 , connects the vacuum system on drilling and back fill system  10  ( FIG. 1 ) to a central vacuum passage  86  ( FIG. 4 ) in digging tool  32 . It should be understood that other types of connectors may be used in place of “banjo” connector  84 , for example clamps, clips, or threaded ends on hose  88  and handle  78 . Referring to  FIGS. 7 and 10 , vacuum passage  86  extends the length of elongated pipe  82  and connects at an end (not shown) to one end of a vacuum hose  88  ( FIG. 11 ). The other end of hose  88  connects to an inlet port  90  on collection tank  14  ( FIG. 11 ). A second end  86   a  of vacuum passage  86  terminates at an opening  87  by a slanted shoulder  89 . 
     Referring to  FIGS. 4 and 5 , a fluid manifold  91 , located at one side  92  of head  93 , connects a water conduit  80  to a water feed line  94  ( FIGS. 4 and 7 ) formed through head  93 . In one embodiment, water feed line  94  is integrally formed in the head during casting of the head. However, it should be understood that the water feed line may also be added to the head after the head is cast. Head  93  contains two sets of a plurality of nozzles  95  and  96 , the first set  95  being angled radially inwardly at approximately 45 degrees from a vertical axis of the digging tool, and the second set  96  being directed parallel to the axis of the digging tool. It should be understood that the angle of first set  95  may be adjusted depending on the application of the digging tool to almost any angle between 0 and 90 degrees to enhance the digging effect of the tool. 
     Each nozzle is set in a countersunk hole  102  formed in a bottom surface  97  of head  93  such that the end of each nozzle is recessed from bottom surface  97 . In particular, if water feed line  94  is integrally cast within the head, a plurality of tap holes  103  ( FIG. 5 ) are drilled into bottom surface  97  so that the holes tap into water feed line  94 . Next, countersunk hole  102  is concentrically formed with tap hole  103 , and the tap hole is threaded. The nozzles are then threadedly attached to the tap hole so that the nozzles are in fluid communication with the water feed line. 
     During use of drilling tool  32 , nozzles  95  and  96  produce a spiral cutting action that breaks the soil up sufficiently to minimize clogging of large chunks of soil within vacuum passage  86  and/or vacuum hose  88 . Vertically downward pointing nozzles  96  enhance the cutting action of the drilling tool by allowing for soil to be removed not only above a buried utility, but in certain cases from around the entire periphery of the utility. In other words, the soil is removed above the utility, from around the sides of the utility, and from beneath the utility. This can be useful for further verifying the precise utility needing service and, if necessary, making repairs to or tying into the utility. 
     Still referring to  FIGS. 4 and 5 , an air feed passage  98  is formed in head  93  and has a first opening  99  at head end  92  and a second opening  100  at a second end  101  of head  93 . In one preferred embodiment, air feed passage  98  is integrally formed in head  93  when the head is cast. However, it should be understood that the air feed may also be formed from tubing extending from head end  93  to head end  101 . In one preferred embodiment, second opening  100  is located at or tangential to bottom surface  97  and may be formed as a single opening or as multiple openings. 
     Traditional vacuum digging tools without an air intake can dig a vertical hole approximately 0-20 feet deep. When an air intake is included in a vacuum digging tool, the digging depth can be extended to a depth of 50 feet or more in the vertical direction. Traditional vacuum digging tools may include air slots located proximate to head end  101  that extend from an outside surface through the head to an inside surface proximate vacuum passage first end  86   a . Therefore, when the tool is used to dig a hole, air is pulled from around the head proximate head end  101 . As a result, when tool is used to remove wet viscous material or discrete material of large particulate size, the air slots are easily clogged, thereby reducing the efficiency and effectiveness of the digging tool. To overcome this disadvantage of prior art digging tools, air intake opening  99  is located distal from head end  101  to prevent clogging or blocking of the air intake. As a result, in the present invention, the vacuum pressure may be maintained at the optimum level regardless of the digging conditions, and the depth of a hole may be extended several times the normal depth. 
     In some embodiments, head  93  may be integrally formed with elongated pipe  82 , and air feed passage first opening  99  may be located anywhere along the length of the elongated pipe, provided the air feed passage first opening is located at a position distal from head second end  101 . Thus, it should be understood that head  93 , whether separate from or integral with elongated pipe  82 , is considered to be a part of the elongated pipe. For purposes of this discussion, distal from the head second end may refer to a position anywhere from several inches away from the head second end to a point proximate the elongated body first end. What should be understood by those of skill in the art is that air intake opening  99  should not be located at any point along head  93  or elongated pipe  82  that would be covered by the material to be removed by the digging tool. It should also be understood in that some embodiments, digging tool  32  may not come equipped with a water feed system. 
     Returning to  FIG. 11 , digging tool  32  may also include a control  106  for controlling the tool&#39;s vacuum feature. Control  106  may be an electrical switch, a vacuum or pneumatic switch, a wireless switch, or any other suitable control to adjust the vacuum action by allowing the vacuum to be shut off or otherwise modulated. An antifreeze system, generally  190  ( FIGS. 1 and 2 ), may be provided to prevent freezing of the water pump and the water system. Thus, when the pump is to be left unused in cold weather, water pump  26  may draw antifreeze from the antifreeze reservoir through the components of the water system to prevent water in the hoses from freezing and damaging the system. 
     Referring to  FIGS. 12-18 , another embodiment of a digging tool  310  has an elongated cylindrical body  312  with a first end  314  and an opposite second end  316 . First end  314  is larger in diameter than pipe second end  316  such that the pipe first end is configured to receive the second end of another pipe section (as shown in  FIG. 17 ) to extend the overall length of the digging tool. In this configuration, the length of elongated pipe  312  can be extended by the use of extender pipes  312   a  ( FIG. 17 ) similar to that in the previously described embodiment. 
     Referring particularly to  FIGS. 13-16 , elongated body  312  is formed from an inner pipe  318  and an outer pipe  320  spaced apart from the inner pipe by a gap  322  such that gap  322  generally extends between body first end  314  and body second end  316 . A plurality of fasteners  324  are located at each end of elongated body  312  and are positioned to secure outer pipe  320  to inner pipe  318 . A plurality of through holes  326  are formed through outer pipe first end  314  proximate to the end of the pipe. It should be understood by those skilled in the art that preferably one elongated pipe  312  would contain holes  326  and that the holes may be contained anywhere along the length of the pipe so long as the holes are distal from pipe end  316 . That is, extension pipes  312   a  would not contain holes  326  since the holes function as an air inlet for air to be fed down the length of elongated pipe  312  through gap  322  to end  316 . For purposes of this discussion, distal from head second end  316  may refer to a position anywhere from several inches away from the head second end to a point proximate the elongated body first end. What should be understood by those of skill in the art is that through holes  326  should not be located at any point along elongated cylindrical body  312  that would be covered by the material to be removed by the digging tool. A center cavity  328  ( FIGS. 13 and 14 ) defined by inner pipe  318  forms a vacuum passageway that is in fluid communication with vacuum hose  88  ( FIG. 12 ). 
     Similar to the previous embodiment, a water feed line (not shown) may be attached to the length of the elongated pipe that terminates in a fluid manifold (not shown). Nozzles (not shown), similar to that in the previous embodiment, may be in fluid communication with the water manifold for use in cutting and breaking up of the digging material. The water feed line may be formed integrally with the elongated pipe, or a separate feed line may be attached to the pipe using clamps, adhesive, fasteners, etc. 
     Referring to  FIGS. 1 and 21 , vacuum pump  28  is preferably a positive displacement type vacuum pump such as that used as a supercharger on diesel truck. In one preferred embodiment, vacuum pump  28  is a Model 4009-46R3 blower manufactured by Tuthill Corporation, Burr Ridge, Ill. A hose  112  connects an intake of the vacuum pump to a vacuum relief device  114 , which may be any suitable vacuum valve, such as a Model 215V-H01AQE spring loaded valve manufactured by Kunkle Valve Division, Black Mountain, N.C. Vacuum relief device  114  controls the maximum negative pressure of the vacuum pulled by pump  28 , which is in the range of between 10 and 15 inches of Mercury (Hg) in the illustrated embodiment. A filter  116  ( FIG. 1 ), located upstream of pressure relief valve  114 , filters the vacuum air stream before it passes through vacuum pump  28 . In one preferred embodiment, the filter media may be a paper filter such as those FleetGuard filters manufactured by Cummings Filtration. Filter  116  connects to an exhaust outlet  118  of collection tank  14  by a hose  120 , as shown in  FIGS. 1, 11, 12 and 21 . An exhaust side  122  of vacuum pump  28  connects to a silencer  124 , such as a Model TS30TR Cowl silencer manufactured by PHILLIPS &amp; TEMRO INDUSTRIES of Canada. The output of silencer  124  exits into the atmosphere. 
     The vacuum air stream pulled through vacuum pump  28  produces a vacuum in collection tank  14  that draws a vacuum air stream through collection tank inlet  90 . When inlet  90  is not closed off by a plug  127  ( FIG. 1 ), the inlet may be connected to hose  88  ( FIGS. 11 and 12 ) leading to digging tools  32  or  312 . Thus, the vacuum air stream at inlet  90  is ultimately pulled through vacuum passages  86  or  328  at distal ends  94  or  312  of tool  32  or  312 , respectively. Because it is undesirable to draw dirt or other particulate matter through the vacuum pump, a baffle system, for example as described in U.S. Pat. No. 6,470,605 (the entire disclosure which is incorporated herein), is provided within collection tank  14  to separate the slurry mixture from the vacuum air stream. Dirt, rocks, and other debris in the air flow hit a baffle (not shown) and fall to the bottom portion of the collection tank. The vacuum air stream, after contacting the baffle, continues upwardly and exits through outlet  118  through filter  116  and on to vacuum pump  28 . 
     Referring again to  FIG. 1 , collection tank  14  includes a discharge door  126  connected to the main tank body by a hinge  128  that allows the door to swing open, thereby providing access to the tank&#39;s interior for cleaning. A pair of hydraulic cylinders  130  (only one of which is shown in  FIG. 19 ) are provided for tilting a forward end  132  of tank  14  upwards in order to cause the contents to run towards discharge door  126 . A gate valve  140 , coupled to a drain  142  in discharge door  126 , drains the liquid portion of the slurry in tank  14  without requiring the door to be opened. Gate valve  140  may also be used to introduce air into collection tank  14  to reduce the vacuum in the tank so that the door may be opened. 
     Running the length of the interior of collection tank  14  is a nozzle tube  132  ( FIG. 21 ) that includes nozzles  66  for directing high pressure water about the tank, and particularly towards the base of the tank. Nozzles  66  are actuated by opening valve  64  ( FIG. 21 ), which delivers high pressure water from pump  26  to nozzles  66  for producing a vigorous cleaning action in the tank. When nozzles  66  are not being used for cleaning, a small amount of water is allowed to continuously drip through the nozzles to pressurize them so as to prevent dirt and slurry from entering and clogging the nozzles. 
     Nozzle tube  132 , apart from being a conduit for delivering water, is also a structural member that includes a threaded male portion (not shown) on an end thereof adjacent discharge door  126 . When discharge door  126  is shut, a screw-down type handle  134  mounted in the door is turned causing a threaded female portion (not shown) on tube  132  to mate with the male portion. This configuration causes the door to be pulled tightly against a sealing flange (not shown) of the collection tank. Actuation of vacuum pump  28  further assists the sealing of the door against the tank opening. Discharge door  126  includes a sight glass  136  to allow the user to visually inspect the tank&#39;s interior. 
     Referring again to  FIG. 1 , backfill reservoirs  20  and  22  are mounted on opposite sides of collection tank  14 . The back fill reservoirs are mirror images of each other; therefore, for purposes of the following discussion, reference will only be made to backfill reservoir  22 . It should be understood that backfill reservoir  20  operates identically to that of reservoir  22 . Similar components on backfill reservoir  20  are labeled with the same reference numerals as those on reservoir  22 . 
     Back fill reservoir  22  is generally cylindrical in shape and has a bottom portion  144 , a top portion  146 , a back wall  148 , and a front wall  150 . Top portion  146  connects to bottom portion  144  by a hinge  152 . Hinge  152  allows backfill reservoir  22  to be opened and loaded with dirt by a front loader  154 , as shown in phantom in  FIG. 1 . Top portion  146  secures to bottom portion  144  by a plurality of locking mechanisms  156  located on the front and back walls. Locking mechanisms  156  may be clasps, latches or other suitable devices that secure the top portion to the bottom portion. The seam between the top and bottom portion does not necessarily need to be a vacuum tight seal, but the seal should prevent backfill and large amounts of air from leaking from or into the reservoir. Front wall  150  has a hinged door  158  that is secured close by a latch  160 . As illustrated in  FIG. 19 , hydraulic cylinders  130  enable the back fill reservoirs to tilt so that dirt can be off loaded through doors  158 . 
     As previously described above, backfill reservoirs  20  and  22  may be filled by opening top portions  146  of the reservoirs and depositing dirt into bottom portion  144  with a front loader. Vacuum pump  28 , however, may also load dirt into back fill reservoirs  20  and  22 . In particular, back fill reservoir  22  has an inlet port  162  and an outlet port  164 . During normal operation, plugs  166  and  168  fit on respective ports  162  and  164  to prevent backfill from leaking from the reservoir. However, these plugs may be removed, and outlet port  164  may be connected to inlet port  90  on collection tank  14  by a hose (not shown), while hose  88  may be attached to inlet port  162 . In this configuration, vacuum pump  28  pulls a vacuum air stream through collection tank  14 , as described above, through the hose connecting inlet port  90  to outlet port  164 , and through hose  88  connected to inlet port  162 . Thus, backfill dirt and rocks can be vacuumed into reservoirs  20  and  22  without the aide of loader  154 . It should be understood that this configuration is beneficial when backfill system  10  is being used in an area where no loader is available to fill the reservoirs. Once the reservoirs are filled, the hoses are removed from the ports, and plugs  166  and  168  are reinstalled on respective ports  162  and  164 . 
     Referring once more to  FIG. 21 , hydraulic cylinders  130 , used to tilt collection tank  14  and backfill reservoirs  20  and  22 , are powered by electric hydraulic pump  30 . Hydraulic pump  30  connects to a hydraulic reservoir  170  and is driven by the electrical system of motor  16 . A high pressure output line  171  and a return line  173  connect pump  30  to hydraulic cylinders  130 . Hydraulic pump  172 , mounted on trailer  24 , is separately driven by motor  16  and includes its own hydraulic reservoir  174 . An output high pressure line  175  and a return line  186  connect pump  172  to a pair of quick disconnect couplings  182  and  184 , respectively. That is, high pressure line  175  connects to quick disconnect coupling  182  ( FIGS. 1 and 2 ) through a control valve  178 , and return line  186  connects quick disconnect coupling  184  to reservoir  188 . A pressure relief valve  176  connects high pressure line  175  to reservoir  188  and allows fluid to bleed off of the high pressure line if the pressure exceeds a predetermined level. A pressure gauge  180  may also be located between pump  172  and control valve  178 . 
     Quick disconnect coupling  182  provides a high pressure source of hydraulic fluid for powering auxiliary tools, such as drilling apparatus  18 , tamper device  185 , or other devices that may be used in connection with drilling and backfill system  10 . The high pressure line preferably delivers between 5.8 and 6 gallons per minute of hydraulic fluid at a pressure of 2000 lbs/in2. Hydraulic return line  186  connects to a quick disconnect coupling  184  ( FIGS. 1 and 2 ) on trailer  24 . Intermediate quick disconnect coupling  184  and hydraulic fluid reservoir  174  is a filter  188  that filters the hydraulic fluid before returning it to hydraulic reservoir  174 . While quick disconnect couplings  182  and  184  are shown on the side of trailer  24 , it should be understood that the couplings may also be mounted on the rear of trailer  24 . 
     Referring to  FIGS. 1 and 2 , drilling apparatus  18  is carried on trailer  24  and is positioned using winch and crane  36 . Drilling apparatus  18  includes a base  192 , a vertical body  194 , and a hydraulic drill motor  196  slidably coupled to vertical body  194  by a bracket  198 . A high pressure hose  200  and a return hose  202  power motor  196 . A saw blade  204  attaches to an output shaft of hydraulic motor  196  and is used to drill a coupon  206  ( FIGS. 11 and 12 ) in pavement, concrete or other hard surfaces to expose the ground above the buried utility. The term coupon as used herein refers to a shaped material cut from a continuous surface to expose the ground beneath the material. For example, as illustrated in  FIG. 11 , coupon  206  is a circular piece of concrete that is cut out of a sidewalk to expose the ground thereunder. 
     Body  194  has a handle  220  for the user to grab and hold onto during the drilling process. Hydraulic fluid hoses  200  and  202  connect to two connectors  222  and  224  ( FIG. 21 ) mounted on body  194  and provide hydraulic fluid to hydraulic drill motor  196 . A crank  226  is used to move the drill motor vertically along body  194 . Drilling apparatus  18  is a Model CD616 Hydra Core Drill manufactured by Reimann &amp; Georger of Buffalo, N.Y. and is referred to herein as a “core drill.” 
     In operation, the location of a hole is determined, and if drill apparatus  18  ( FIG. 2 ) was used to remove a coupon from the site, the user disconnects vacuum hose  88  from the drill and connects the hose to digging tool handle  78  using banjo connector  84 . High pressure water hose  70  is also connected to valve  74  to provide water to the digging tool as deemed necessary. As tool  32  is used to dig a hole, it is pressed downwardly into the ground. For larger diameter holes, digging tool  32  is moved in a generally circular manner as it is pressed downward thereby removing material from a large cross-section area. Slurry formed in the hole is vacuumed by tool  32  through vacuum passage  86  ( FIGS. 4 and 5 ) and accumulates in collection tank  26 . Once the hole is completed and the utility exposed, the vacuum system can be shut down, and the operators may examine or repair the utility as needed. 
     Alternatively, referring to  FIGS. 12 and 18 , elongated body second end  316  may be inserted into the area where a hole is desired. Referring to  FIG. 18 , as a vacuum stream is pulled up vacuum passage  328 , an air current  330  is pulled through gap  322 , which is fed through holes  326 . The air pulled into vacuum passage  328  from gap  322  allows the vacuum system to remove dirt and/or water more efficient and effectively than a tool without the additional air flow. Moreover, the placement of air inlet holes  326  distal from the vacuum end ensures that the air stream does not become clogged or blocked. It should also be understood that the embodiment shown in  FIGS. 12-18  may be combined with a water feed line (not shown) and high pressure nozzles (not shown) to deliver high pressure water to body end  316 . 
     After work on the utility is completed, and referring to  FIG. 19 , the operator may cover the utility with clean backfill from backfill reservoirs  20  and  22 . In particular, trailer  24  is positioned so that one of backfill reservoirs  20  or  22  is proximate the hole. Hydraulic cylinders  130  are activated, causing the tanks to tip rearward so that backfill can be delivered through door  158  into the hole. Once the hole is sufficiently filled, hydraulic cylinders  130  return reservoirs  20  and  22  to their horizontal position, and door  158  is secured in the closed position. 
     With reference to  FIG. 20 , operator  34  may use a tamping device  185  to tamp the backfill in the hole. Tamping device  185  connects to hydraulic pump  172  through quick disconnect couplings  182  and  184  via hydraulic lines  200  and  202 . Tamping device  185  is used to pack the backfill in the hole and to remove any air pockets. Once the hole has been filed and properly packed, coupon  206  is moved into the remaining portion of the hole. The reuse of coupon  206  eliminates the need to cover the hole with new concrete. Instead, coupon  206  is placed in the hole, and grout is used to seal any cracks between the key and the surrounding concrete. Thus, the overall cost and time of repairing the concrete is significantly reduced, and the need for new concrete is effectively eliminated. 
     Drilling and backfill system  10  can be used to dig multiple holes before having to empty collection tank  14 . However, once collection tank  14  is full, it can be emptied at an appropriate dump site. In emptying collection tank  14 , motor  16  is idled to maintain a vacuum in tank  14 . This allows the door handle to be turned so that the female threaded member (not shown) is no longer in threading engagement with the male member (not shown) on nozzle rod  132 , while the vacuum pressure continuing to hold the door closed. Once motor  16  is shut down, the vacuum pressure is released so that air enters the tank, thereby pressurizing the tank and allowing the door to be opened. Once opened, hydraulic cylinders  130  can be activated to raise forward end  132  upward dumping the slurry from the tank. 
     Collection tank  14  may also include a vacuum switch and relay (not shown) that prevents the tank from being raised for dumping until the vacuum in the tank has dropped below a predetermined level for door  126  to be opened. Once the vacuum in the tank has diminished to below the predetermined level, tank  14  may be elevated for dumping. This prevents slurry from being pushed up into filter  116  if door  126  can not open. 
     In an alternate embodiment shown in  FIGS. 22-27 , collection tank  14  is equipped with a sealing flange  415 , a discharge door  426  connected to the main tank body by a hinge  428 , and an automatic discharge door closer  400 . Automated discharge door closer  400  has two linkage assemblies  430 A ( FIGS. 22 and 24 ) and  430 B ( FIGS. 23 and 25 ), each including an upper linkage arm, a lower linkage arm, and an actuating cylinder. For ease of discussion, reference will be made to  FIGS. 22, 24, 26 and 27  to describe linkage assembly  430 A, where all reference numbers are annotated with a capital “A.” However, it should be understood that the same components exist for linkage assembly  430 B shown in  FIGS. 23 and 25 . Any differences between the linkage assemblies will be pointed out. 
     Referring to  FIG. 24 , a lower linkage arm  434 A has a lower edge  479 A and a first end  435 A rigidly connected to a linkage assembly pivot bar  438  at the pivot bar&#39;s first end  440 A. Pivot bar  438  extends from its first end  440 A through the outer wall of collection tank  14  and into an internal chamber  414 . The pivot bar has a longitudinal axis  442  oriented generally parallel to a diameter of the collection tank  14 . The pivot bar extends along its axis  442  through the tank internal chamber  414  and further extends through the opposite side of the collection tank outer wall and terminates at a pivot bar second end  440 B ( FIGS. 23 and 25 ). In one preferred embodiment, a sealed bearing  444 A rotatably engages pivot bar  438  at the point where the pivot bar passes through the collection tank external wall to ensure that tank internal chamber  414  remains sealed from the outside atmosphere. The rigid connection of lower linkage arm first ends  435 A ( FIG. 24 ) and  435 B ( FIG. 25 ) with respective first and second pivot bar ends  440 A ( FIG. 24 ) and  440 B ( FIG. 25 ) entrains both of the lower linkage arms with the pivot bar so that the lower linkage arms rotate in unison with the pivot bar. 
     First lower linkage arm  434 A has a second end  437 A and an actuating cylinder mounting hole (not shown) intermediate its first and second ends. In one preferred embodiment, actuating cylinder  436 A is a hydraulic cylinder having a cylinder housing  446 A and a piston rod  448 A that is slidably received in housing  446 A. Piston rod  448 A has a free end  450 A that is adapted for pivotal attachment to the lower linkage arm cylinder mounting hole. Preferably, a pin connection  451 A pivotally attaches piston rod free end  450 A to the cylinder mounting hole (not shown) by a clevis, eyebolt or other similar pivotal linkage. 
     A pivot pin  439 A pivotally connects first lower linkage arm second end  437 A with a first end  431 A of an upper linkage arm  432 A. Upper linkage arm  432 A has a second end  433 A that adjustably receives a threaded portion of an eye bolt  452 A. Eye bolt  452 A has an eye (not shown) that is pivotally connected to a first end  454 A of a cross bar  456 . Thus, the threaded connection between upper linkage arm second end  433 A and cross bar first end  454 A allows for adjustment of the space between the upper linkage arm second end and the cross bar first end. 
     Referring to  FIG. 26 , cross bar  456  is rigidly mounted to discharge door  426  by means of an attachment cylinder  460 . Door  426  has a door panel  425  that is preferably dome-shaped, and attachment cylinder  460  is located on the interior surface of discharge door panel  425  directly opposite the center or origin of the exterior surface of the door panel. As described in further detail below, the location of attachment cylinder  460  at the center (origin) of the door panel helps maximize the strength of the seal when the discharge door if fully closed. In one preferred embodiment, attachment cylinder  460  receives a bolt  462  that passes through both the attachment cylinder and dome-shaped door panel  425  and is securely fastened to cross bar  456  by a nut  464  ( FIG. 22 ). A secondary disk  466  reinforces the connection between the attachment cylinder  460  and door  426  to prevent the dome-shaped discharge door panel  425  from dimpling or deforming when door  426  is sealed against collection tank sealing flange  415 . It should be understood that door panel  425  may be flat, concave or convex as shown in the figures and the shape is based on the application of the door. 
     Referring to  FIG. 24 , collection tank  14  is depicted with discharge door  426  in a fully opened position. Automated linkage assembly  430 A and  430 B ( FIG. 25 ) and pivot bar  438  cooperate with hinge  428  to rotate discharge door  426  into and out of sealing engagement with collection tank flange  415 . When closing the discharge door from its fully open position, actuating cylinder  436 A retracts piston rod  448 A. The pivotal pin connection  451 A between piston rod free end  450 A and lower actuating arm  434 A forces lower actuating arm  434 A and therefore pivot bar  438  to pivot so that lower actuating arm second end  437 A rotates in the direction of arrow  470 . 
     Referring to  FIG. 25 , the rigid connection between the second lower actuating arm first end  435 B and pivot bar second end  440 B forces second lower actuating arm  434 B to rotate in the direction of arrow  471  in response to the retraction of actuating cylinder  436 A ( FIG. 24 ). Additionally, an actuating cylinder  436 B, connected similar to actuating cylinder  436 A, may simultaneously retract a piston rod  448 B as actuating cylinder  436 A retracts its piston rod, resulting in increased closing force applied to lower actuating arms  434 A and  434 B and pivot bar  438 . Actuating cylinders  436 A and  436 B represent a system redundancy because the actuation of either actuation cylinder forces both lower actuating arms to rotate due to their rigid attachment to pivot bar  438 . Accordingly, one of the actuating cylinders may be omitted without altering the function of the automated door. Moreover, should one of the actuating cylinders fail during operation, the other can operate the opening and closing of the door so as to maintain the functional integrity of the system. It should be understood that the lower actuating arms do not necessarily need to be rigidly attached to pivot bar  438  but instead may be rotatable with respect to the pivot bar. Thus, in this configuration, each actuating cylinder would drive its respective lower actuating arm. 
     In operation and referring to  FIGS. 24 and 25 , as the lower actuating arms rotate in response to the retraction of one or more of the cylinder piston rods, first and second lower actuating arm second ends  437 A and  437 B exert a downward force on upper actuating arm first ends  431 A and  431 B, through pivot pins  439 A and  439 B. The downward force applied on upper actuating arm first ends  431 A and  431 B pulls the upper actuating arms downward and away from the collection tank open end causing upper actuating arm second ends  433 A and  433 B to pull cross bar  456  downward in the direction of arrow  472 . As the cross bar travels in the direction of arrow  472 , the rigid connection between cross bar  456  and discharge door  426  forces door hinge  428  to pivot the door into closing engagement with collection tank sealing flange  415 . Discharge door  426  has a flange  427  about its outer periphery that forms a sealed engagement with collection tank flange  415  once the discharge door fully closes. It should be understood that a gasket (not shown) may be attached to one of tank flange  415  or door flange  427  to assist in forming an airtight seal when the door in the closed position. 
     Referring to  FIG. 27 , once discharge door flange  427  seals with tank flange  415 , actuating cylinder  436 A continues to retract piston rods  448 A. As the piston rod further retracts, lower actuating arm second end  437 A enters into its respective seating bracket  474 A and. Seating bracket  474 A has a recess  476 A with a bottom seat surface  478 A. When the lower actuating arm has rotated sufficiently to bring its lower edge  479 A into contact with seat surface  478 A, the contact between the actuating arm lower edges and the seat surface prevents further rotation of the lower actuating arms. The same holds true for linkage assembly  430 B on the opposite side of tank  14 . 
     Seating bracket  476 A is preferably positioned such that lower actuating arm lower edge  479 A contact seat surface  478 A only when pivot point  439 A is located at a position below a horizontal line  480  that intersects the pivot bar longitudinal axis  442 . This condition is commonly referred to as “rotation beyond overcenter,” and  FIG. 27  shows automated linkage assembly  430 A when placed in this position. Because of the entrained movement of both automated linkage assembly  430 A and automated linkage assembly  430 B, both linkage assemblies respond identically as they rotate beyond overcenter. In this position, door  26  is biased in the closed position and will remain in the closed position should actuating cylinders  446 A and  446 B fail. That is, because pivot points  439 A and  439 B are rotated beyond overcenter, lower actuating arms  434 A and  434 B cannot rotate in a direction opposite arrows  470  ( FIG. 24 ) and  471  ( FIG. 25 ) unless they are actively biased in those directions to a point above line  480 . As a result, in this position, the door is considered biased into the closed position since an active force must bias the lower actuating arm pin connections back overcenter into the open position. 
     When opening door  426  from its closed position, actuating cylinder  436 A extends piston rod  448 A upward causing pivot point  439 A to rotate in a direction opposite to arrow  470  above center line  480 . This rotation cause upper actuating arm  432 A to move rearward toward the tank open end causing door  426  to pivot upward on hinge  428 . As lower actuating arm  434 A rotates, pivot bar  438  also rotates causing linkage assembly  430 B to move similar to that of linkage  430 A. Additionally, actuating cylinder  436 B ( FIG. 25 ) may simultaneously extend piston rod  448 B as actuating cylinder  436 A extends its piston rod  448 A, resulting in an increased opening force applied to lower actuating arms  434 A and  434 B. Thus, as the lower actuating arms rotate in the opening direction, the upper actuating arms urge cross bar  456 , and therefore door  426 , to travel opposite the direction indicated by arrow  472  ( FIG. 25 ). 
     Referring to  FIGS. 24 and 25 , once door  426  is in the fully open position, an operator may lock lower actuating arms  434 A and  434 B in the open position. Preferably, two bearing brackets  484 A and  484 B mounted to the external surface of tank  14  each have a locking pin hole (not shown) sized appropriately to receive an end of a respective locking pin  486 A and  486 B. Additionally, the lower actuating arms each have a corresponding locking pin hole  490 A and  490 B ( FIGS. 22 and 23 ) also sized appropriately to receive locking pins  486 A and  486 B. Thus, when the actuating cylinders rotate the lower actuating arms into their fully open position, lower actuating arm locking pin holes  490 A and  490 B align with the bearing bracket locking pin holes (not shown), and the operator may insert locking pins  486 A and  486 B through the two aligned holes. In this way, locking pins  486 A and  486 B secure the lower actuating arms in the fully open position ensuring that door  26  remains open when tank  14  is being cleaned. 
     Referring to  FIGS. 25 and 26 , locking pins  486 A and  486 B are tethered to a safety guard  488 A and  488 B by a lanyard  489 A and  489 B so that the operator will not misplace the locking pins. Safety guards  488 A and  488 B perform the dual function of protecting the operator from pinch points created by the articulating automated linkage assemblies  430 A and  430 B and providing a storage hole  487 A and  487 B to receive the locking pins when not in use. 
     As previously stated, the above discussion was directed primarily to linkage assembly  430 A. However, one of skill in the art should understand that the discussion holds equally for linkage assembly  430 B. Moreover, while not shown in the figures, one of skill in the art should understand that automated linkage assemblies  430 A and  430 B may be operated by a control panel at the back of the vehicle, at a control panel located inside the vehicle or remotely by a wireless or wired control panel. One or more of these control panels may be provide to operate the automated assembly. 
     The above described embodiments of the automated door closer provide several advantages. First, rotating the lower actuating arm  434 A and  434 B into the “beyond overcenter” condition maximizes the amount of sealing force exerted by cross bar  456  upon discharge door  426 . Second, placing the lower actuating arms in the “beyond overcenter” condition ensures that the door is maintained in the closed position. However, the contact between lower actuating arm lower edges  479 A and  479 B and seating bracket seat surfaces  478 A and  478 B prevents further rotation in the direction of arrows  470 A and  470 B. This arrangement presents a significant safety advantage. 
     Another significant advantage of the automated door closer is the fact that it provides an even seal around the entire circumference of the discharge door. The location of the contact between cross bar  456  and discharge door  426  at the center of the door panel allows an evenly distributed force to be applied between the door flange and the tank flange ensuring a tight seal. That is, the location of attachment cylinder  460  ensures that all compressive closing force applied to the door will be located at the center of the door  426 . In this way, the compressive force is transferred uniformly out to the outer circumference of door  426 . In prior art designs, the closing force is usually applied to one or two opposite points on the door periphery. In such designs, while the closing force ensures a tight seal proximate the connection points, it fails to ensure a tight seal around the entire periphery of the door. 
     It should be appreciated by those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope and spirit of the invention. It is intended that the present invention cover such modifications and variations as come within the scope and spirit of the appended claims and their equivalents.