Submersible Dredge

Abstract

A dredging system including a submersible, occupant-operated vehicle having an excavating tool carried thereby; a conduit extending from said tool to a location where said excavated material is to be deposited; a shore installation; and power and air conduits connecting said installations with the vehicle. The system is applicable to the excavation of large areas such as submerged deposits of sand and silt; the formation of narrow, deep trenches such as those utilized for various pipelines and cables; and the grading of level or specifically contoured areas for preparing the bottom for prefabricated structures.

Description

Heretofore, dredging operations have been primarily conducted from floating platforms. Such systems are restricted to relatively calm water conditions and therefore have been inefficient or inapplicable for many dredging operations. Further, dredging operations conducted from the water's surface are restricted to relatively shallow depths by limitations of suction head, or in the case of bucket dredges, by the feasible ladder length.

A principal objective of this invention is to provide a system for underwater dredging wherein a self-contained dredging vehicle, having quarters and facilities for an operating crew, is capable of excavating on the bottom of a body of water generally without regard to water surface conditions.

Another principal objective of this invention is to reduce maintenance problems by mounting the slurry conduits and the suction pump external to the hull of the vehicle housing the electrical and mechanical equipment within the hull. As a result, the crew has access to the equipment for inspection and maintenance thereof at comfortable atmospheric conditions. The power equipment for the suction pump is located within the hull of the vehicle and the pump itself is exterior thereof. This arrangement requires that a drive shaft must extend through the vehicle hull. A further objective of this invention is to provide a novel inflatable seal about the shaft which permits the inspection and replacement of the shaft packing glands from the vehicle's interior while submerged.

Another objective of this invention is to provide a dredging apparatus for operation on the bottom of a body of water which requires no surface components other than power and air supply lines communicating from the apparatus to the shore or other surface installation.

A still further objective of this invention is to provide a dredging vehicle which permits its operator to have direct visual contact with the excavating tool during submerged dredging operation whereby a more efficient dredging operation is assured. The vehicle is provided with an operator's chamber with means for maintaining the interior atmosphere thereof at conditions compatible with human requirements for extended periods of time.

Another important objective of this invention is to provide the underwater vehicle of this invention with an air-water lock chamber for the ingress and egress of replacement crews while the dredge remains submerged at the area of dredging operations.

A further objective of this invention is to provide the submergible vehicle of this invention with an operator-controlled, tool-carrying boom. The controls available to the operator for swinging the boom include circuitry for pre-setting boom swing at predetermined rates with further means provided to reduce the rate of boom swing upon a sensing that the lateral forces exerted against the boom exceed a pre-set force level. Thus, when the tool is not excavating materials as rapidly as the tool is being moved into the material, the circuitry will reduce the rate of swing until the desired pre-set force is reached. Further, if the tool should become buried in the material to be excavated, the controls will decrease the lateral force until the rate of swing becomes zero.

A still further objective of this invention is in the provision of an adjustable valve, operable from within the vehicle, for purposes of permitting additional water to enter the suction conduit of the system between the tool and the pump. If the tool, or the conduit between the tool and pump, becomes fully or partially clogged, it is possible by operating this valve to adjust and control the proportion of solids and water in the slurry mixture until the conduit is cleared. Also the slurry mixture can be varied for increased efficiency in the removal thereof.

Another objective of this invention is to provide means to vary the submerged weight of the vehicle by increasing or decreasing the volume of sea water in the vehicle ballast tanks. By so controlling the weight of the vehicle, the traction between its traction members and the bottom surface can be adjusted.

A still further objective of this invention is to provide outrigger spuds which can be inserted into the bottom surface so as to resist lateral twist or movement of the vehicle during boom swing. The spuds serve the additional function of leveling the vehicle when desired.

These and other objectives of the invention will become more apparent to those skilled in the art by reference to the following detailed description when viewed in light of the accompanying drawings wherein:

FIG. 1 is an underwater perspective of the dredging system;

FIG. 2 is a side elevation of the submergible vehicle;

FIG. 3 is a top plan of the vehicle with portions broken away;

FIG. 4 is a side elevation of the vehicle with portions broken away;

FIG. 4A is a diagrammatic showing of one component of the submersible vehicle;

FIG. 4B is a diagrammatic showing of a portion of the hydraulic system;

FIG. 5 is a cross-section along the line 5--5 of FIG. 4;

FIG. 6 is a diagrammatic cross-section of a seal assembly; and

FIG. 6A is an enlargement of a portion of FIG. 6.

Referring now to the drawings wherein like numerals indicate like elements, the numeral 10 indicates the dredging system of this invention. The dredging system is comprised generally of a submersible vehicle 12, a control station 14, a dredging conduit 16, and an air-communication-power cable assembly 18.

As duscussed in the objectives, the purpose of this dredging system is to remove materials from the vicinity of the vehicle 12 to a remote location such as that indicated by the letters R and R1. The system herein described has wide application and is uniquely adaptable for contouring, removing material and forming trenches on the bottom of a body of water.

The slurry conduit or dredging hose 16 is comprised of a series of segments or sections 17 which are attached together by conventional means. The conduit leads from the vehicle 12 to a stakedown position P. At position P, a Y-connection can be placed in the line by known methods. From position P, the excavated material recovered by the vehicle 12 can be exhausted either to a location R or to location R1. Installation 14 is relatively fixed and includes such equipment as power generators, air compressors and the like. The installation 14 is located as near to the dredging site as possible. The conduit portion 19 between the shore and position P, through the surf area, is normally buried. At the Y-connection, a second conduit section 22 can be readied while vehicle 12 is excavating in the area shown. An area of several miles along the shoreline can be controlled from the single installation 14.

The air-communication-power cable assembly 18 extends between the surface installation 14 and the vehicle 12. Under some conditions, it is advisable to attach buoys 26 at intervals along the length of the conduit 16. The buoyancy of these members is set to cause the hose to be suspended above the bottom whereby drag on the dredge is reduced and the hose is protected from the bottom surface. When pumping a heavy slurry, it is, of course, advisable to have the support of the bottom surface and the buoy can be so designed. The cable assembly 18 can be secured to these buoyancy means.

The submersible vehicle 12 includes an operator chamber and an equipment chamber which are respectively defined by hulls 32 and 30. The hulls 30 and 32 are mounted on a framework 31 which includes a pair of spaced I-beams 34. A pair of ground-engaging track assemblies 36 and 38 are mounted on either side of the framework 31. Mounted forwardly of the vehicle 12 is a boom member generally indicated by the numeral 40. The boom is generally comprised of tubular beams 41, 42 and 43. At their outermost ends, the beams are welded to the exterior of the conduit section 44. At its outermost end, the conduit 44 is adapted to receive a plurality of replaceable cutter-head assemblies 48. The disclosed cutter-head assembly 50 is driven by a hydraulic motor 52. The motor 52 receives hydraulic fluid through conventional hydraulic circuitry 53. Intermediate their lengths, the beam members 41, 42 and 43 are spaced and joined by braces or struts 54 and 56.

A fifth wheel assembly 60 is mounted at the forward end of the vehicle. The fifth wheel assembly includes a rotatable upper plate 62 having lugs 64 extending upwardly therefrom. Plate 62 is rotatable about the vertical axis 66 as shown in FIGS. 4 and 4A. The boom assembly 40 is mounted for vertical movement about the axis 67 of lugs 64. The turntable is provided with stop means which limit the boom to a 45.degree. swing to each side of the longitudinal center line of the vehicle 12. Thus, it can be seen that the boom 40 is mounted to vehicle 12 with limited universal movement. Movement is controlled by a plurality of hydraulic jacks. A hydraulic jack 70 is provided for movement in the vertical plane. The jack 70 has cylinder end 71 pivotally secured to an ear 72 at the top of hull 32 and its piston end connected to ear 74 mounted to the boom assembly 40 near braces or struts 54 and 56. The turntable plate 62 is under the control of a pair of hydraulic jacks 65. The jacks 65 have their cylinder ends pivotally connected to a lug member 63 which is attached to the vehicle framework and their piston ends pivotally connected to turntable plate 62 at joints 71 on either side of axis 66. With conventional hydraulic controls, an operator seated on chair 75 and looking through window 76, is able to observe and control the position and direction of assembly 48. As mentioned above, control circuitry 77 permits him to pre-set movement at a desired rate.

The conduit section 44 spans the distance between the excavating tool 48 and the intake opening of an impeller-type suction pump 80. A portion 81 of conduit 44 is flexible to permit swinging of the boom. The pump 80 exhausts through a conduit segment 82 which comprises the first of the sections making up the conduit 16. As seen best in FIG. 1, the conduit line 16 is supported by and extends over hull 30.

The principal power means for vehicle 12 are located within the chamber 30. In particular, reference is made to power source 86 having its power output transmitted to impeller pump 80 by way of a drive shaft 88. Between the motor 86 and shaft 88 is an electro-magnetic coupling 89 to vary the speed of the pump and to isolate the motor from the pump when starting the motor. A gear reduction unit 90 is located between the coupling 89 and pump 80. Also within the hull 30 is an auxiliary motor and pump 91 to power the hydraulic elements and control systems. Other auxiliary equipment is generally located diagrammatically at 93. All of the above mechanical equipment is driven by electricity received through cable assembly 18.

The operator's quarters enclosed within the hull 32 is a compact unit having the operator seat 95 and a bed 96 for the off-duty operator. The hull also includes a small galley 98. Such an arrangement permits a crew to remain submerged for many hours.

In submerged equipment of the prior art, it has oftentimes been difficult to repair, service and maintain the engine motors and pumps of the submerged equipment. In the system of this invention, the more delicate and difficult to repair items are housed within the chamber 30 which is maintained at atmospheric conditions. A passageway 100 is provided to enable the operator in chamber 32 to enter the power equipment chamber 30. Side-hung hatches 101 and 103 isolate the hull 30 from hull 32 for safety reasons. These hatches also isolate the crew from the heat and noise generated by the mechanical equipment.

A bulkhead 102 across chamber 30 forms a work chamber 104. A sealing assembly 106 is disposed about shaft 88 at opening 108 to isolate the chamber 104 from the exterior of hull 30. Assembly 106 can best be understood with reference to the enlarged, somewhat diagrammatic cross-sections of FIGS. 6 and 6A. The shaft 88 extends to pump 80 through the opening 114 of hull 30. The assembly is comprised of an annular ring 110 having annular flanges 120 and 122 at either side thereof. An inwardly directed flange 126, with that portion of hull 30 adjacent opening 108, forms an annular chamber 128 for the reception of an outwardly extending flange 130 of the drive flange 88. By receiving the shaft 130 in chamber 128, longitudinal displacement of the drive shaft is prevented.

Inwardly of flange 126 is an annular, inflatable sealing ring 132 and a packing gland 134. The packing gland is retained in place by retainer plate 136 which is bolted or otherwise secured to flange 122. Due to the rotation of shaft 88, the packing 134 needs replacement at regular intervals. The inflatable seal 132 is utilized to seal the chamber 104 from the surrounding water during the replacement of the packing. Note that the seal is communicated to a source of compressed air by way of line 140. The packings are communicated to a source of water via a line 142 for lubricating purposes during initial start up. When replacing the packing gland, the seal 132 is inflated, the packings 134 are replaced. Upon completion, seal 132 is deflated and plate 136 is replaced. In its deflated condition, the seal 132 is not in any particular engagement with the shaft and thus will not wear because of frictional engagement with the shaft. Note that a second packing 112 of bulkhead 102 is equipped with an inflatable seal 113 for the same purposes. In practice, a certain amount of lubricating water is permitted to leak through packings 134 and remain within the chamber 104. As diagrammatically seen in FIG. 6, the level of this bilge is maintained by way of valve assembly 144 in outlet assembly 146 by having pressure raised beyond the ambient outside pressure. An air compressor 145 maintains the pressure in 104 at a slightly elevated pressure over that maintained in hulls 30 and 32 and above the ambient water pressures. Since the pressure is elevated slightly above exterior ambient water pressure, inflow is prevented through the packing gland when replacing same. By elevating pressure via 145, leakage is also controlled.

The shaft 88 is rotatably supported by a bearing 147 within hull 30 and by a bearing 149 within chamber 104. A mechanic can gain head access to chamber 104 through opening 151 and hand access through opening 153. These openings are normally closed by coverlets 155 and 157 respectively.

Returning now to the exterior of the vehicle, it can be seen that extending outwardly from the framework 31 are four stabilizing spuds 150, 152, 154 and 156. The spuds are hydraulically driven into the bottom surface in those locations where stability of the vehicle cannot be maintained by the tracks alone. The spuds are used to resist torque induced by boom movement and to level the vehicle to assure boom swing in the horizontal plane. The earth-engaging ends of the spuds are actually the piston members of double-acting cylinders 150a, 152a, 154a and 156a. These double-acting cylinders are hydraulically controlled from within the chamber 32 by conventional controls.

A passageway 160 leads outwardly from chamber 30 to an escape hatch 162. The escape hatch is of conventional design and is adapted to receive a pressurized bell member B which lowers replacement crews to the vehicle. At relatively shallow depths swimmers can gain access through the bottom of the hatch. Divers at deeper levels can also gain access by this means.

In setting up for a dredging operation, shore installation 14 is located as near the dredging operation as possible. In some circumstances, the shore installation is actually located on a floating platform. The shore installation includes the apparatus necessary to furnish air, power and communication to the vehicle 12 via the cable assembly 18. A station P is located on the bottom surface centrally of the area to be dredged. Conduit sections are laid from location P to the vehicle 12 which is previously driven to the dredging area. Note that the dredging conduit can be folded or nested to give some play to conduit line 16 as the vehicle 12 moves forwardly.

In a general manner, while there has been disclosed effective and efficient embodiments of the invention is not limited to such embodiments as there might be changes made in the arrangement, disposition, and form of the parts without departing from the principle of the present invention.

Claims

We claim:

1. A dredging system comprising

a self-propelled submergible vehicle having an enclosed operator chamber and a separately enclosed equipment hull,

a boom pivotally mounted to said vehicle,

an excavating tool mounted on said boom,

a suction conduit having one end disposed at said tool and the other end thereof leading to a remote location,

a suction producing pump intermediate the length of said conduit and mounted to the exterior of both said hull and said chamber,

power means within said equipment hull,

a drive shaft extending through an opening in said equipment hull and drivingly connecting said power means to said pump, and means sealing said opening.

2. The system of claim 1 wherein said means sealing said opening is a packing gland which circumscribes said shaft where it extends through said hull, wherein separate sealing means is provided to permit the replacement of said packing gland from the interior of said vehicle.

3. The system of claim 2 wherein said separate sealing means includes an annular inflatable seal positioned between the periphery of said opening and said shaft whereby said seal is inflated to prevent water from entering said equipment hull through said opening when said gland is replaced.

4. The system of claim 3 wherein said packing gland is located interiorly of said seal whereby access thereto from the interior of said vehicle is provided.

5. A dredging system comprising an installation having sources of air and power located near the shore of the area to be dredged,

a connection member located centrally of the area to be dredged,

a buried conduit extending from the shore to said member,

a submersible excavation vehicle having an equipment hull,

a second conduit extending from said member to said vehicle,

a power line, communication line, and air hose extending between said installation and said vehicle,

buoyant means for suspending said second conduit from the bottom surface of the area being dredged and said buoyant means are comprised of a series of lighter than water members attached at spaced intervals along the length of said second conduit,

a boom pivotally mounted externally of said vehicle,

a tool mounted on said boom,

a suction pump mounted exteriorly of said equipment hull,

a suction conduit communicating said tool with said pump,

a power means within said equipment hull,

a drive shaft extending through an opening in said equipment hull and drivingly connected to said pump, and

means sealing said opening.

6. The system of claim 5 wherein traction members are mounted on said vehicle and power means within said vehicle drive said members.

7. A submersible vessel comprising

a framework,

a first enclosed hull mounted on said framework containing quarters for an operating crew,

a boom,

means pivotally connecting said boom to said first hull,

an excavating tool carried by said boom,

an enclosed equipment hull separate from said first hull,

a suction pump mounted on said framework adjacent to and to the exterior of said equipment hull,

a drive means within said equipment hull,

a drive shaft between said drive means and said pump and extending through an opening in said equipment hull,

a packing gland sealing said opening,

means to seal said opening to allow replacement of said packing gland when said vehicle is beneath the surface of the water,

a conduit between said excavating tool and said pump, and

a second conduit extending from said pump to an area where excavated material is to be deposited.

8. The vehicle of claim 7 wherein hydraulic means control the pivotal movement of said boom.

9. The vehicle of claim 8 wherein said hydraulic means are hydraulic jacks under the control of an operator within said first hull.

10. The vehicle of claim 9 wherein a passageway extends between said first and said equipment hulls and closure means can close said passageway.

11. The vehicle of claim 10 wherein a plurality of outriggers extend from said vehicle, spuds are attached to said outriggers and control means can selectively lower said spuds into the surface over which said vehicle rests whereby said vehicle can resist torque forces caused by a swinging movement of said boom.