Remotely operated submerged dredging system

Abstract

A remotely operated underwater dredging system that can excavate many hundreds of feet below the surface of a water body. By placing dredge pump at the bottom of the water body, the vacuum to lift water and dredged material to the pump is minimized. In addition, the mechanical advantage of the cutterhead can be greatly enhanced by mounting it directly to a submerged dredging chassis close to the pump.

1 . A submerged remotely operated cutter head dredging system for excavating a cut in a workface located at the bottom of a body of water, the system comprising:
 a chassis comprising a first track and a first car mounted on the track for movement along the track;   a pump and cutter head cutter head assembly mounted on the car for movement with the car along the track, the pump and cutter head cutter head assembly comprising (1) a dredging pump (2) a dredging cutter head and (3) means for driving the pump and the cutter head;   means for propelling the car along the track;   means for effecting movement of the pump and cutter head assembly into and away from the workface;   a plurality of extendable and retractable spuds fastened to the chassis, the spuds being extendable into a bottom surface of the body of water for supporting and stabilizing that chassis, and   one or more buoyant submerged discharge pipes for transporting a slurry of water and material excavated by the pump and cutter head assembly, the buoyant discharge pipes being coupled to a fixed submerged discharge pipe leading to the surface of the body of water.   
   
   
       2 . The system as recited in  claim 1 , wherein the means for effecting movement of the pump and cutter head assembly comprises two or more parallel hydraulic cylinders carried by the chassis and oriented perpendicular to the track, the cylinders acting between the chassis and the track carrying the pump and cutter assembly for forcing the car and the pump and cutter head assembly toward the workface. 
   
   
       3 . The system as recited in  claim 2 , and further comprising an additional retractable and extendable spud fixed to the track at each end of the track for stabilizing the track and the pump and cutter head assembly while excavating. 
   
   
       4 . The system as recited in  claim 1 , and further comprising:
 a second track parallel to the first track;   a second car mounted on the second track and coupled to the first car by a beam and a hydraulic cylinder;   an extendable and retractable spud fastened to the second car, whereby, with the spud on the second car extended into bottom surface of the body of water and all of the other spuds retracted, propulsion applied to the first and second car car effects movement of the chassis along the workface.   
   
   
       5 . The system as recited in  claim 4 , wherein movement forcing of the pump and cutter head assembly and first track into the workface is effected by (1) selectively extending and retracting spuds on the first and second tracks and (2) actuating the hydraulic cylinders. 
   
   
       6 . The system as recited in  claim 4 , wherein one of (1) a rack and pinion, (2) a jackscrew and (3) an endless cableway is provided in each track for propelling the cars along the first track to extend the cut made by the cutterhead. 
   
   
       7 . The system as recited in  claim 1 , and further comprising a main umbilical conduit providing electric power, control data, and compressed air from surface facilities for powering motors in, and providing operational commands to, submerged components of the system. 
   
   
       8 . The system as recited in  claim 7 , and further comprising:
 a main hydraulic pump mounted on the dredge and providing hydraulic power to all spuds, hydraulic cylinders and hydraulic motors in submerged components of the system; and   an electric branch line leading to an electric motor driving the main hydraulic pump.   
   
   
       9 . The system as recited in  claim 7 , and further comprising:
 a plurality of anchors connected by cables to winches on the dredge;   a variable buoyancy attitude control tank mounted to each anchor;   a plurality of variable buoyancy attitude control tanks mounted on the chassis;   a plurality of variable buoyancy attitude control tanks mounted on each of the discharge pipes;   a conduit for pressurized air incorporated into the umbilical cable; and   a master control valve carried by the chassis and connected to the conduit for pressurized air, for supplying air for delivery to the control tanks.   
   
   
       10 . The system as recited in  claim 9 , and further comprising:
 an ROV connected by an umbilical conduit to the main umbilical conduit and to the master control valve for (1) delivering electrical power and (2) delivering pressurized air to the control tanks, for adjusting the buoyancy of the control tanks, applying thrust to reposition anchors and performing other tasks about the bottom of the body of water.   
   
   
       11 . A submerged remotely operated cutter head dredging system for excavating a cut in a workface located at the bottom of a body of water, the system comprising:
 a spar pivotally coupled at one end to a plow anchored in the bottom of the body of water, the spar being supported at its other end by a movable carriage, whereby the other end of the spar is movable along a curved path determined by pivoting movement of the spar about the plow;   a pump and cutter head cutter head assembly mounted to the other end of the spar for movement with the other end of the spar and the carriage along the workface, the pump and cutter head cutter head assembly comprising (1) a dredging pump (2) a dredging cutter head and (3) means for driving the pump and the cutter head;   means for propelling the carriage along the workface; and   one or more buoyant submerged discharge pipes for transporting a slurry of water and material excavated by the pump and cutter head assembly, the buoyant discharge pipes being coupled to a fixed submerged discharge pipe leading to the surface of the body of water.   
   
   
       12 . The system as recited in  claim 11 , wherein the means for propelling the carriage comprises one of (1) a rack and pinion and (2) an endless cableway provided adjacent to the other end of the spar. 
   
   
       13 . The system as recited in  claim 11 , wherein the carriage comprises wheels mounted at the other end of the spar. 
   
   
       14 . The system as recited in  claim 12 , wherein the carriage comprises wheels mounted at the other end of the spar. 
   
   
       15 . The system as recited in  claim 11 , and further comprising a main umbilical conduit providing electric power, control data, and compressed air from surface facilities for powering motors in, and providing operational commands to, submerged components of the system. 
   
   
       16 . The system as recited in  claim 15 , and further comprising
 a plurality of variable buoyancy attitude control tanks mounted on each of the discharge pipes;   a conduit for pressurized air incorporated into the umbilical cable; and   a master control valve carried by the other end of the spar and connected to the conduit for pressurized air, for supplying air for delivery to the control tanks.   
   
   
       17 . The system as recited in  claim 16 , and further comprising:
 an ROV connected by an umbilical conduit to the main umbilical conduit and to the master control valve for (1) delivering electrical power and (2) delivering pressurized air to the control tanks, for adjusting the buoyancy of the control tanks, applying thrust to reposition anchors and performing other tasks about the bottom of the body of water.   
   
   
       18 . The system as recited in  claim 11 , wherein the carriage is supported on and movable along a curved track located adjacent to the other end of the spar. 
   
   
       19 . The system as recited in  claim 18 , wherein the means for propelling the carriage comprises one of (1) a rack and pinion and (2) an endless cableway mounted onto the curved track. 
   
   
       20 . A pump and cutter head assembly for use in a dredging system, the pump and cutter head assembly comprising:
 a pump incorporating (1) a large diameter volute provided with a discharge port and (2) a unitary assembly of a large diameter impeller and a suction tube rotatably mounted on the volute;   a plurality of planetary driving devices mounted on the volute and engaging a periphery of the impeller for driving the impeller and suction tube; and   a dredging cutter head coupled to the impeller for receiving driving force from the impeller.