Excavator system

Abstract

An excavation system includes a shroud having a first opening and a second opening, a nozzle for directing an air stream in a first direction through the first opening of the shroud, wherein the nozzle is surrounded by the shroud, a first pump configured to apply a suction within the shroud in a second direction through the second opening of the shroud, and a collection area in fluid communication with the second opening of the shroud for receiving contaminated material. The collection area includes a collector for separating the contaminated material via an impact plate and a filter. The contaminated material is then deposited into a bag supported by a box. A method for excavating the contaminated material from the ground is also disclosed.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of Provisional Application No. 60/416,638, filed Oct. 7, 2002, entitled “Excavator Head”, which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to excavation of soil and, more particularly, the use of pneumatic excavation.

[0004] 2. Description of Related Art

[0005] Throughout the twentieth century, various areas throughout the United States have become contaminated with various hazardous chemicals and radioisotopes. Specifically, these contaminants have been deposited on the ground and eventually make their way, in many cases, to the ground water supply. Heretofore, excavation primarily included removal of the soil by such means as bulldozers and other types of mechanical digging and lifting devices. Mechanical diggings may produce significant wind blown emissions when soil is excavated or dumped from one container into another container. After the soil is removed, it is then sifted and then disposed of at an appropriate site or incinerated. In many cases, a majority of the removed soil is not contaminated. It has been found that the contamination, in many cases, is found in fines, such as the size of sand particles contained in the soil and located near the soil surface. Prior art methods have typically removed the non-contaminated larger rocks. The more material that needs to be disposed, the greater the cost of the disposal. Therefore, it is an object of the invention to quickly and easily remediate soil where the contamination is only directed to fines found in the soil. It is a further object to reduce the amount of contaminated airborne dust during the removal process.

SUMMARY OF THE INVENTION

[0006] The present invention is an excavation system designed to loosen the first couple of inches of soil and direct only the fine grain portion into a vacuum system. Preferably, the system includes a head that is held by the operator, roughly perpendicular to and in close proximity to the soil surface. The head is traversed or moved horizontally over the ground surface from about one-half to two feet per second by the operator. A supersonic air nozzle is provided at the center of the head to produce and direct a supersonic jet air stream at approximately Mach 2 towards the surface, loosening and agitating the top couple of inches of soil. Typically, many particles will pick up appreciable speed and be directed upwardly parallel to the axis of the jet air stream. A deflector plate may be provided to serve and intercept these high speed particles and cause them to fall back into the air stream flowing from outside the head. A gap is defined between the head and the ground so that air can be drawn into the head in a direction opposite to the jet air stream by a vacuum pump. The velocity of the air through this gap and up into the head will be at, or greater than, the floating velocity of the fine grained, i.e., sand-sized or smaller, particles of the soil. For a 2 millimeter sized sand particle, the floating, or terminal velocity, is about 1,150 feet per minute. After entering the head, the air and debris carried by the air is drawn by the vacuum pump and will rise in an annular fashion along an inside surface of the shroud. The distance between the shroud and the deflector plate is chosen such that the velocity in the gap is the same as the floating velocity for the sand. A first chamber or lower chamber is defined below the deflector plate and the jet air stream from the supersonic nozzle sets up a circulation bringing the fine-grained portion of the soil into contact with the rising air flow created by the vacuum pump limiting the vacuum flow velocity to the floating velocity of the sand so that only the fine-grained portion of the soil will be carried into a second chamber or an upper chamber of the head. The upper chamber is defined above the deflector plate. The upper chamber gradually narrows to attach to a vacuum hose leading to a collection area. The velocity above the deflector plate gradually increases to the level needed to transport the fine-grained material to the collection area through the hose. For example, a 3 inch diameter hose may utilize approximately 200 to 300 standard cubic feet per minute of air (scfm) to transport the fine material through the hose.

[0007] These and other advantages of the present invention will be understood from the description of the preferred embodiments, taken with the accompanying drawings, wherein like reference numerals represent like elements throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a side elevational view, partially in section, of an excavator head made in accordance with the present invention;

[0009] FIG. 2 is a schematic elevational view of the excavation system having an excavator head and a collector made in accordance with the present invention;

[0010] FIG. 3 is a side elevational view of an alternative embodiment of the excavator head of FIG. 1 and

[0011] FIG. 4 is a side elevational view, partially in section, showing an alternative embodiment of the collector of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An excavation system 10 made in accordance with the present invention is shown in FIGS. 1-4. The system 10 includes a collection area 11, a vacuum remedial head 12, and a pneumatic tool 14 received by the head 12. The pneumatic tool 14 operates in a similar fashion as a hand tool disclosed in U.S. Pat. No. 5,966,847 to Nathenson et al. (sold under the trademark AIR-SPADE®), which is hereby incorporated by reference. The pneumatic tool 14 includes a supersonic converging/diverging nozzle 16 fluidly coupled to a barrel 18. The barrel 18 is coupled to a pump or air compressor 20. Preferably, the pneumatic tool 14 is designed so that air exiting the supersonic converging/diverging nozzle 16 travels at a speed of Mach 2 and a volume of 25 to 60 standard cubic feet per minute (scfm) at 90 pounds per square inch gauge (psig). It is to be understood that the referenced speeds and corresponding volumes are described for exemplary purposes and may therefore vary depending on the specific dimensions and other physical characteristics of the present invention.

[0013] The vacuum remedial head 12 includes a shroud 22 having a receiving cavity 24 defined by an inner surface of the shroud 22. The shroud 22 includes a cylindrical entrance portion 26 attached at its upper end to a frusta-conical shaped converging portion 28, although the converging portion 28 may be any suitable shape. An upper end of the converging portion 28 is attached to a cylindrical exit portion 30. Preferably, the diameter of the cylindrical entrance portion 26 is greater than the diameter of the cylindrical exit portion 30.

[0014] The excavation system 10 includes a collection arrangement. Specifically, a conduit or hosing H1 is provided and coupled to the cylindrical exit portion 30 and is coupled to a collector 32. The collector 32 is a cylindrical vessel built to withstand a vacuum and houses a filter 34 and an impact plate 36. The collector 32 is suspended above a spoils box B containing a soft-sided soil disposal bag R that acts as a removable liner. The collector 32 houses a primary chamber 38 where the majority of the incoming soil particles from the air stream are removed by impact and a secondary chamber 40 where the remaining dust is collected by the filter 34. All of the collected material is continuously discharged from the collector 32 through a rotary valve 42 down directly into the spoils bag R. Special multi-layer soil disposal bags, such as the Lift-Liner™, have been qualified to transport hazardous or radioactive waste and may be used in this application. The filter 34 may be additionally of HEPA quality. The box B provides structural support to hold the bag during filling. A lid L is provided to contain any dust within the bag R. Alternately, the lid may be integral with the bag R connecting to the rotary valve 42 via a spout (not shown). The collector may also contain a blow back system, which typically uses compressed air to clean the filter 34. A conduit or hosing H2 connects the outlet of the collector 32 to the inlet of a vacuum pump 44. The vacuum pump 44 draws the clean air from the inside of the filter 34 and exhausts the air through a silencer 46 to an exit port 48. The vacuum pump 44 may be belt-driven by a gas or diesel engine or an electric motor 50. Finally, the pump or air compressor 20 is also driven by the electric motor 50 and provides compressed air via a conduit or hosing H3 to the barrel 18. This collection arrangement, including the collection area 11 and the vacuum pump 44 may also be similar to that disclosed in U.S. Pat. No. 5,860,232, which is hereby incorporated by reference.

[0015] Returning to the vacuum remedial head 12 of FIG. 1, the cylindrical entrance portion 26 has a lower open-faced end which defines an entrance 54 to the vacuum remedial head 12. An optional cylindrical deflector plate 56 is positioned within the receiving cavity 24 defined in the cylindrical entrance portion 26. The deflector plate 56 is preferably attached to the barrel 18 of the pneumatic tool 14, although it may also be attached to the nozzle 16. The deflector plate 56 defines an annular restricted flow area 58 between an outer edge of the deflector plate 56 and the inner surface of the cylindrical entrance portion 26. This annular restrictive flow area 58 permits an increased flow velocity of air particles flowing through the annular restrictive flow area 58. The deflector plate 56 defines a first or lower chamber 60 and a second or upper chamber 62 within the cylindrical entrance portion 26. The lower chamber 60 and upper chamber 62 are in fluid communication with each other through the annular restricted flow area 58.

[0016] In practice, an operator positions a lower edge 64 of the vacuum remedial head 12 above the surface of the soil or ground 66. Typically, the ground 66 contains fines or sand of fine-grain and other small debris, having a size of 2 millimeters or less. Preferably, the lower edge 64 is positioned about one inch above the ground 66, forming a gap 68 between the lower edge 64 and the ground 66. It is to be understood that the distance of the lower edge 64 and the ground or ground 66 can be varied to adjust the gap 68, which in turn adjusts the flow rate and vacuum characteristics of the excavation system 10. Flexible bristles 70 cover the resultant gap 68 between the lower edge 64 and the surface of the ground 66. The bristles 70 maintain a flexible contact with the surface of the ground or ground 66, thereby preventing any dislodged soil particles from exiting the remedial head 12, yet allowing air to enter. It is understood that one or more layers of flexible bristles 70 may be used to cover the gap 68. It is also to be understood that other types of flexible seal members may be used to maintain a flexible contact with the surface of the ground 66 including, one or more of such flexible seal members.

[0017] The pump 20 of the pneumatic tool 14 is activated so as to cause an air stream exiting from the supersonic converging/diverging nozzle 16. Preferably, the nozzle 16 is designed to permit the air to exit at approximately Mach 2 toward the ground 66. The nozzle 16 and pump 20 should be designed so that the air stream exits at 25 to 60 scfm and at a pressure of 90 psig, although other flow rates, operating pressures, and jet stream velocities would suffice, depending on a case-by-case basis. Likewise, the vacuum pump 44 is activated so as to cause air to pass through the shroud 22 toward the collection area 11 at a volumetric rate of 200-300 scfm. The actual dimensions of the shroud 22, cylindrical exit portion 30, vacuum pump 44, and volumetric flow rate depend on a case-by-case basis. For exemplary purposes, the floating or terminal velocity of a 2 millimeter sized particle is about 1,150 feet per minute. Generally, the appropriate flow rate should be such that the velocity of the air is sufficient to carry that size of a particle. However, the flow rate should not be so great as to carry a larger particle, such as rocks, etc.

[0018] While the air compressor 74 and the vacuum pump 44 are activated, the operator moves the vacuum remedial head 12 over the surface of the ground 66 at an approximate rate from ½ to 2 feet per second. The air stream exiting the pneumatic tool 14 through the nozzle 16 exits in a supersonic air stream in a direction shown by arrow 72. This air stream causes the ground 66 to break apart and become dislodged as loose particles. These particles then travel upwardly toward the shroud 22. If the deflector plate 56 is provided, particles having a high velocity will contact the deflector plate 56 as shown by arrow 74. Desirably, the deflector plate 56 is substantially parallel to the ground 66. After making contact with the deflector plate 56, the particles will then be directed toward the ground 66 in the direction as designated by arrow 76. A pressure differential created by the vacuum pump 44 results in suction within and throughout the shroud 22 and the conduit and hosing H1. This upward air flow throughout the shroud 22 will carry the particles, such as the sand particles, in an upward direction as shown by arrow 78, in the lower chamber 60. The particles will be carried at a higher velocity through the restricted flow area 58 and will then be carried into the upper chamber 62 through the cylindrical exit portion 30 in the direction shown by arrow 80. The particles are then routed to the collector 32. Specifically, the contaminated particles, such as the fines or sands of fine-grain, have been excavated and stored for safe disposal in the bag R. The air accompanying the particles may then pass through the filter 34. The filtered air may then be routed to the vacuum pump 44 and the silencer 46 and expelled through the exit port 48 into the environment. By loading the bag R directly for disposal, further contamination of the air is avoided as would be typical with mechanical excavators or conventional vacuum trucks, which have to be dumped, once full.

[0019] FIG. 3 illustrates an alternative embodiment vacuum remedial head 82 having similar components as the vacuum remedial head 12 but embodied in a different configuration. The alternative embodiment vacuum remedial head 82 excludes the deflection plate 56 and has the exit portion 30 located below the barrel 18 in the frusta-conical shaped converging portion 28. Additionally, the alternative embodiment vacuum remedial head 82 may include two sets of bristles 70. The disclosed configurations of vacuum remedial heads are only for exemplary purposes and are not to be considered as limiting the invention.

[0020] FIG. 4 illustrates an alternative embodiment collector 84 having somewhat similar components as the collector 32 but embodied in a different configuration. The alternative embodiment collector 84 eliminates the rotary valve 42. Contaminated material enters the collector 84 via the conduit or hosing H1 and strikes the impact plate 36. The contaminated material is then directed into the spoils bag or removable liner R lining the box B. A vacuum causes the air in the contaminated material to pass through the filter 34 and be expelled through the exit port 48. An additional filter 86 of HEPA quality may be added to the collector 84. The flow path is indicated by arrows.

[0021] The present invention has been described with reference to the preferred embodiments. Obvious modifications, combinations, and alterations will occur to others upon reading the preceding detailed description. It is intended that the invention be construed as including all such modifications, combinations, and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. An excavation system, comprising:

a shroud having a first opening and a second opening;

a nozzle for directing an air stream in a first direction through the first opening of the shroud, the nozzle surrounded by the shroud;

a first pump configured to apply a suction within the shroud in a second direction through the second opening of the shroud; and

a collection area in fluid communication with the second opening of the shroud.

2. The excavation system of claim 1, wherein the nozzle is connected to a barrel, the barrel positioned in and extending from the shroud.

3. The excavation system of claim 2, wherein the shroud comprises a first chamber and a second chamber, the first chamber adjacent to the first opening of the shroud and the second chamber adjacent to the second opening of the shroud.

4. The excavation system of claim 3, further comprising a deflector plate received within the shroud, wherein the shroud defines a flow passageway adjacent to the deflector plate and an inner surface of the shroud.

5. The excavation system of claim 4, wherein the deflector plate is positioned between the first chamber and the second chamber of the shroud.

6. The excavation system of claim 5, wherein the deflector plate is substantially parallel to a ground area.

7. The excavation system of claim 6, further comprising a flexible seal member positioned adjacent the first opening of the shroud.

8. The excavation system of claim 7, wherein the flexible seal member comprises a plurality of bristles.

9. The excavation system of claim 1, further comprising a second pump in fluid communication with the barrel, the second pump configured to create the air stream to be delivered through the barrel.

10. The excavation system of claim 1, wherein the suction is sufficient to carry particles having a diameter of 2 millimeters or less.

11. The excavation system of claim 1, wherein the collection area is comprised of a container with lid, the container lined with a removable liner.

12. A method for excavating material from the ground, comprising the steps of:

directing an air stream in a first direction toward a material to be removed;

causing the material to be dislodged by the air stream to move the dislodged material in a second direction;

providing suction in the second direction to carry the dislodged material in the second direction; and

collecting the removed material and directly depositing the collected material into a bag.

13. The method of claim 12, further comprising the steps of:

providing a shroud having a first opening and a second opening;

providing a nozzle for directing the air stream toward the ground through the first opening of the shroud;

providing a first pump configured to apply the suction through the second opening of the shroud; and

providing a collection area in fluid communication with the second opening of the shroud to receive the removed material.

14. The method of claim 13, further comprising the step of providing a barrel positioned in and extending from the shroud, the barrel connected to the nozzle and a second pump.

15. The method of claim 14, wherein the second pump is configured to create the air stream to be delivered through the barrel.

16. The method of claim 13, further comprising the step of moving the nozzle over a ground area.

17. An excavator head, comprising:

a shroud having a first opening and a second opening;

a nozzle for directing an air stream in a first direction through the first opening of the shroud, the nozzle surrounded by the shroud, wherein the nozzle is connected to a barrel, the barrel positioned in and extending from the shroud; and

a flexible seal member positioned adjacent to the first opening of the shroud.

18. The excavator head of claim 17, further comprising a deflector plate received within the shroud, wherein the shroud defines a flow passageway adjacent to the deflector plate and an inner surface of the shroud for flow from the first opening to the second opening.

19. A collector for receiving contaminated material, the collector comprising:

a chamber for receiving an air stream having contaminated materials;

an impact plate situated within the first chamber, the impact plate configured to remove the contaminated material from the air stream;

a filter situated within the chamber; and

means for cooperating with a bag suitable for collection and transportation of hazardous material.

20. The collector of claim 19, further comprising a rotary valve positioned between the chamber and the container, the rotary valve configured to discharge the contaminated material into the container.