Patent Abstract:
The present invention is directed to a drilling fluid reclaimer. The reclaimer has at least one adjustable screen assembly for providing a leveling filter for reclaimed drill fluid. Used drill fluid is placed at the screen assembly at the front the of the screen assembly. The at least one screen is vibrated to separate large particulate matter from liquid drilling fluid. A second screen is provided for additional filtering. Large particulate matter is expelled by a chute at the back of the screen assembly. Drilling fluid passing through the screen is “reclaimed” for use with a drilling system.

Full Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of provisional patent application Ser. No. 61/750,149, filed on Jan. 8, 2013, and provisional patent application Ser. No. 61/833,084, filed on Jun. 10, 2013, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD 
     The present invention relates generally to the field of excavation using a fluid and a system for recycling the fluid. 
     SUMMARY 
     The present invention is directed to a reclaimer located proximate an excavation site. The reclaimer comprises a screen assembly, a conduit for transporting excavation fluid from the excavation site to the screen assembly, a first vibrator operatively attached to the screen assembly, and a leveling assembly for adjusting an orientation of the screen assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side perspective view of a fluid reclaimer system of the present invention with a soft excavation arm. 
         FIG. 2  is a back perspective view of an alternative embodiment of the fluid reclaimer system. 
         FIG. 3  is a perspective view of an airlock for use with the system of  FIG. 1 . 
         FIG. 4  is a cross-section side view of the airlock of  FIG. 3 . 
         FIG. 5  is a partial cross-section side view of the soft excavation unit for use with the system of  FIG. 1 . 
         FIG. 6  is a top back perspective view of the embodiment of the fluid reclaimer system. 
         FIG. 7  is a side view of the fluid reclaimer system in use with a horizontal directional drilling system. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention is a reclaimer for regenerating excavation fluid to re-use the fluid in excavation operations. In ordinary excavation operations using horizontal directional drilling systems, drilling fluid is pumped through a drill string to a location proximate a drill head to lubricate the drill head and case the process of drilling. After fluid is used at the point of drilling, it travels back up the borehole, collecting particulate matter such as drilling spoils, environmental dirt, and metal along the way. The fluid, upon returning to the surface, would be better described as used drill fluid, or “spent mud”, unsuitable for reuse in the drill head due to the corrosive particles contained within it. 
     The reclaimer of the present invention provides a method for processing spent mud to remove particulate matter from the spent mud to reclaim drilling fluid for drilling operations. This decreases the amount of fluid required for an excavation operation. 
     With reference to the figures in general and  FIG. 1  particularly, shown therein is a drilling fluid reclaimer system  10  in accordance with the present invention. The system  10  is shown on a trailer  12 . The trailer  12  comprises a hitch  14 , a frame  16 , and a plurality of ground engaging members  18 . The hitch  14  provides a connection to a vehicle (not shown) that pulls the system  10  to a job site. The frame  16  supports various components of the system  10 , which will be discussed in greater detail below. The ground engaging members  18  as shown, are wheels. One of ordinary skill can appreciate that tracks may alternatively be used as ground engaging members  18 , and that either wheels or tracks may be powered by a drive motor. Alternatively, the trailer  12  may be integrally formed with a self-powered truck. 
     The system  10  comprises a power pack  20 , a fluid tank  22 , a reclaimer  24 , and a mixer  26 . The system  10  further comprises a fluid delivery system  28  for transporting fluid to and from an excavation site. As shown, the fluid delivery system  28  comprises a soft excavation unit  30 , an airlock  32 , and a pump  34 . One skilled in the art will appreciate that other fluid delivery systems may be used with the reclaimer system  10  of the present invention, such as a system for delivering fluid to a downhole bit in a boring operation ( FIG. 7 ). 
     The power pack  20  provides power for operating the various electronic and hydraulic components of the reclaimer system  10 . The fluid tank  22  stores drilling fluid for use with the drilling fluid delivery system  28 . Preferably, as shown in  FIG. 1 , the fluid tank  22  comprises multiple chambers  36 . Each of the chambers may contain a different fluid, such as water, unused fluid, and recovered fluid from operation of the reclaimer system  10 , as will be described in more detail below. 
     The fluid delivery system  28  further comprises a fluid delivery channel  40  and a fluid return channel  42 . The fluid delivery channel  40  may be a hose or other delivery device to accommodate fluid as it moves from the fluid tank  22  to an excavation site. As shown, the excavation site is a location for soft excavation by the soft excavation unit  30 . Fluid is moved from the fluid tank  22 , through the fluid delivery channel  42  to the soft excavation unit  30 . The fluid is then used to aid in soft excavation—the uncovering of a buried utility without the use of a bit. 
     The pump  34  provides a pressure to push new fluid and used fluid through the fluid delivery system. The pump  34  may be any commercially available pump suitable for pumping fluid used in excavation operations and may be operated by conventional means, such as hydraulic or electrical power. 
     As shown, the fluid delivery system may further comprise a vacuum system  44  for providing a vacuum pressure at the soft excavator  30 . This pressure pulls used fluid mixed with particulate matter such as dirt (called “spent mud”) into the fluid return channel  42  and into the airlock  32 . The airlock  32  separates air from spent mud, as the an is pushed through the vacuum system  44 . Spent mud leaves the airlock  32  and is applied to the reclaimer  24 . 
     The reclaimer  24  comprises a plurality of desilter cones  50 , a vibrator  52 , a screen assembly  54 , and a reclaimed fluid tank  55 . Spent mud is processed through the plurality of desilter cones  50  to remove fluid from the courser particulates. One skilled in the art will appreciate that desilter cones  50  accept the spent mud tangentially into its body. The centrifugal force induced by the flow causes the heavier solids and slurries to separate from lighter material. The heaviest solids are deposited out the bottom of the cones  50  to the screen assembly  54  and the lighter liquid removed out the top for reuse. The desilter cones  50  are located above the screen assembly  54  and deposit spent mud thereon. 
     The vibrator  52  is attached to the screen assembly  54 . Spent mud is processed on the screen assembly  54  by vibration of the vibrator  52 . The vibrator  52  may vibrate the entire screen assembly  54  at the same frequency, or may alternatively comprise a first vibrator and a second vibrator to vibrate different parts of the screen assembly at different frequencies. 
     The reclaimer  24  processes the spent mud to cause particulate matter to be separated from the drilling fluid, or slurry portion, as will be described in greater detail with reference to  FIG. 2  below. The drilling fluid is dropped into the reclaimed fluid tank  55  and then returned to a chamber  36  of the fluid tank  22 . Particulate matter processed by the reclaimer  24  is dropped into the mixer  26 . 
     The mixer  26  allows the particulate matter removed from the reclaimer  24  to dry, or for drying agents to be added to the particulate matter to aid in drying. Dry particulate matter may be left on the ground, or removed to a secondary site for further drying and processing. 
     With reference now to  FIG. 2 , the system  10  is shown in an alternative configuration without the mixer  26  ( FIG. 1 ) and with the fluid tank  22  located next to the reclaimer  24 . This alternative configuration may be used with a horizontal directional drill ( FIG. 7 ). The reclaimer  24  further comprises a chute  56  and a leveling assembly  58 . As shown, desilter cones  50  are located at a first end  60  of the reclaimer and the chute  56  is located at a second end  62  of the reclaimer. The vibrator  52  is centered over the screen assembly  54  to enable uniform vibration throughout the screen assembly, if desired. The screen assembly  54  comprises a first screen  64  and a second screen  66 . The first screen  64  is shown located above the second screen  66 . The second screen  66  thus may comprise a finer mesh such that smaller particulate matter that passes through the first screen  64  is filtered out of the fluid by the second screen. 
     The chute  56  allows filtered particulate matter falling off the first screen  64  and second screen  66  at the second end  62  of the reclaimer  24  to drop to the ground or into a mixer  26  ( FIG. 1 ) with a clearance between filtered particulate matter and the back of the trailer  12 . The chute  56  comprises a chute frame  70 . The chute frame  70  may be adjusted to change the angle of the chute  56  relative to the ground and thus the distance between the deposited particulate matter and the back of the trailer  12 . 
     The leveling assembly  58  adjusts the orientation of the screen assembly  54  and may comprise at least one cylinder  80 . As shown, the cylinder  80  is proximate the second end  62  of the reclaimer. As shown, the cylinder  80  adjusts an orientation of the screen assembly  54  relative to the reclaimed fluid tank  55 . The leveling assembly  58  may comprise more than one cylinder to enable a tilt adjustment of the first screen  64  and second screen  66  front-to-back and right-to-left. The leveling assembly  58  may alternatively comprise a pinned or slotted connection (not shown) between the screen assembly  54  and the reclaimed fluid tank  55 . It is generally desirable for the leveling assembly  58  to position the first screen  64  and second screen  66  higher at the front end than at a back end of the screen assembly, while maintaining a level orientation from side-to-side. Thus, if the trailer  12  is on uneven terrain, the screen assembly  54  can maintain a flat orientation. Further, moisture content and flowrate of the spent mud may make it advantageous for the spent mud to spend more or less time on the screen assembly  54 , which can be modified through front-to-back tilt of the screen assembly. A level sensor (not shown) may be provided to determine the front-to-back and side-to-side tilt of the screen assembly  54 . The first screen  64  may be locked with the second screen  66  in orientation. Alternatively, in some applications it may be advantageous to provide the first screen  64  and second screen  66  with different or variable front-to-back tilt to maximize the reclamation of drilling fluid due to differing composition of material at the first screen and at the second screen. 
     Fluid passing through both the first screen  64  and the second screen  66  is collected in the reclaimed fluid tank  55 , returned to the fluid tank  22 , and thus “reclaimed” by the system  10  for use in excavation operations. Fluid is then provided through the excavation operations as described above, either alone or combined with unused fluid. 
     With reference now to  FIG. 3 , the airlock  32  is shown in more detail. The airlock  32  comprises an upper tank  90  and a lower tank  92 . The lower tank  92  comprises a sprocket  94  driven by a motor  95  for driving rotation of internally located impellers  112  ( FIG. 4 ). 
     As previously discussed, the fluid return channel  42  transports used fluid from the jobsite to the air lock  32 . Used fluid enters the airlock  32  from the fluid return channel  42  at the upper tank  90 . Air present in the fluid return channel  42  is removed from the airlock  32  through vacuum channel  96  located at the top of the upper tank. The vacuum channel  96  also provides maintenance of a vacuum pressure within the airlock  32  so that a vacuum pressure is delivered to the soft excavation unit  30  as will be described in more detail with reference to  FIG. 5 . Spent mud that enters the airlock  32  at the fluid return channel  42  exits at the bottom of the lower tank  92 . 
     With reference now to  FIG. 4 , internal components of the airlock  32  are shown. The upper tank  90  comprises a support bar  100 , a float comprising a float ball  102 , an inlet  104  and a vacuum exit  106 . Air and spent mud enter the upper tank  90  from the fluid return channel  42  ( FIG. 3 ) at the inlet  104 . The support bar  100  holds the float ball  102  in a position below the vacuum exit  106 . Spent mud is pulled toward the lower tank  92  due to gravitational force. The float ball  102  will float on the top surface of spent mud if the amount of in the upper tank  90  rises. Thus, before the spent mud threatens to exit the airlock  32  through the vacuum exit  106 , the float ball  102  will seal the vacuum exit, preventing mud from entering the vacuum system  44  ( FIG. 1 ). 
     The lower tank  92  comprises a mechanical flow regulator, such as an impeller  108 . The impeller  108  comprises a plurality of arms  112 , each with a flap  114  that contacts an inner surface  115  of the lower tank  92 . The motor  95  drives the sprocket  94  ( FIG. 3 ) which, in turn, rotates the impeller  108 . As the arms  112  of the impeller  108  rotate, spent mud is removed from the airlock  32  and allowed to move to the reclaimer  24  ( FIG. 1 ). The flaps  114  prevent the ambient pressure outside the airlock  32  from causing the upper tank  90  to lose vacuum pressure within the airlock  32 . 
     With reference now to  FIG. 5 , the internal workings of the soft excavation unit  30  are in cross-section. The soft excavation unit  30  comprises a body  118  with an opening  119 , at least one jet  120 , an internal shaft  122 , and a rotating bit  124 . The at least one jet  120  directs drilling fluid  126  to a surface of the ground. The rotating bit  124  is driven by the internal shaft  122  and is located within the body  118  such that no portion of the rotating bit extends beyond the opening  119  of the soft excavation unit  30 . In this way, the rotating bit  124  is prevented from contacting an underground object and merely aids in displacing soil located within the perimeter of the opening  119 . 
     One skilled in the art will appreciate that a vacuum pressure may be provided proximate the opening  119  so that spent mud can be removed from the site of soft excavation. This vacuum pressure may be provided between the shaft  122  and the body  118  such that spent mud is removed by the soft excavation unit  30  itself. Alternatively, a separate fluid return channel  42  ( FIG. 1 ) may be provided at the site of soft excavation to remove spent mud. In either case, spent mud removed from the soft excavation location is directed to the airlock  32  ( FIG. 3 ). 
     With reference to  FIG. 6 , the system  10  is shown with the mixer  26  located under the chute  56 . The mixer comprises at least one rotating arm  130 . Particulate matter in the mixer  26  may still be wet. In many locations, wet particulate matter may not be deposited on the ground or used to re-fill a pit used for drilling or a pothole created by the soft excavation unit  30 . Thus, particulate matter entering the mixer may be mixed with a drying agent and stirred by the rotating arms  130  or an auger (not shown) in order to dry the particulate matter such that it may be deposited at the job site rather than at a disposal facility. 
     While most of the figures above have shown the system  10  in use with a soft excavation unit  30 , the configuration shown in  FIG. 7  may also be effective. With reference to  FIG. 7 , the system  10  is shown in use with a horizontal directional drilling system  200 . The horizontal directional drilling system  200  comprises a carriage  202 , a drill string  204  and a bit  206 . The drill string  204  enters the ground at a drilling location  208 . The carriage  202  provides thrust and rotation to the bit  206 . Drilling fluid is provided from the fluid tank  22  of the system  10  to the horizontal directional drilling system  200  by way of fluid delivery channel  40 . This drilling fluid may travel down the drill string  204  for use at the bit  206  to aid in drilling operations. Thus, the drill string may comprise a conduit through which fluid is transported from the surface to the drill bit. Fluid is injected into the borehole surrounding the drill bit and mixes with dirt, metal shavings, and other particulate matter to form spent mud which returns up the bore hole in the space between the outside of the drill string and the surface of the borehole to the drilling location  208 . The spent mud may then be moved to the system  10  for processing by the reclaim  24  by way of the return channel  42 . A pump  210  may also be connected to the return channel  42  to help pump the spent and back into the system  10 . 
     One skilled in the art will appreciate the variations that may be effective in this invention. For example, auger boring, rock boring and vertical drilling operations which make use of drilling fluid may be adapted for the present invention such that drilling fluid can be reclaimed for repeated use.

Technology Classification (CPC): 1