Patent EA-001345-B1 (EA)
Title: Underwater excavation apparatus
Inventor: SUSMAN HECTOR FILLIPUS ALEXAND
IPC: E02F5/28
Filed: 1996-12-19
Abstract: 1. An underwater excavation apparatus (300a; 300b; 300c) comprising a hollow body (370a; 370b; 370c) having at least one pair of inlets (371a; 371b; 371c) and at least one outlet (373a; 373b; 373c), at least one pair of impellers (335a; 335b; 335c, 340a; 340b; 340c) rotatably mounted in the hollow body and means for driving the impellers (310a; 310b; 310c), wherein the driving means cause the impellers to be driven in contrary rotating directions and wherein the at least one pair of inlets is inclined at an angle to an axis along which the at least one outlet is provided. 2. An underwater excavation apparatus as claimed in claim 1, wherein the at least one pair of inlets (371a; 371b; 371c) are substantially symmetrically disposed around an axis extending from the outlet (373a; 373b; 373c). 3. An underwater excavation apparatus as claimed in any of claim 1 or 2, wherein the apparatus comprises a pair of horizontally opposed inlets (371c) communicating with a single outlet (373c), the outlet being disposed vertically downwards substantially midway between the two inlets, in use, such that the excavation apparatus is substantially "Y" shaped in profile. 4. An underwater excavation apparatus as claimed in any of claims 1 to 3, wherein the apparatus comprises a pair of inlets (371c) communicating with a single outlet (373c), the inlets being substantially symmetrically disposed around an axis extending from the outlet, the outlet being disposed vertically downwards substantially midway between the two. 5. An underwater excavation apparatus as claimed in either of claims 3 or 4, wherein at least one impeller (335c, 340c) is provided within each inlet. 6. An underwater excavation apparatus as claimed in any preceding claim, wherein the means for driving the/each impellers (335a; 335b; 335c, 340a; 340b; 340c) includes at least one drilling motor (310a; 310b; 310c). 7. An underwater excavation apparatus as claimed in claim 6, wherein the at least one drilling motor (310a; 310b; 310c) comprises a stator (21, 51) and a rotor (23, 53) rotatably mounted in the stator, the stator being provided with a rod recess 75 and an exhaust port (33, 63) the rotor being provided with a rotor channel (27, 57) and at least one channel (28, 58) for conducting motive fluid from the rotor channel to a chamber between the rotor and the stator, the rod recess being provided with a rod (71) which, in use, forms a seal between the stator and the rotor. 8. An underwater excavation apparatus as claimed in claim 7, wherein the rotor is provided with a seal (76) for engagement with the stator. 9. An underwater excavation apparatus as claimed in claim 8, wherein the seal (76) is made from a material selected from the group consisting of plastics materials, polyethylethylketone, metal, copper alloys and stainless steel. 10. An underwater excavation apparatus as claimed in any of claims 7 to 9, wherein the rod (71) is made from a material selected from the group consisting of plastics materials, polyethylethylketone, metal, copper alloys and stainless steel. 11. An underwater excavation apparatus as claimed in any of claims 7 and 10, wherein the stator (21, 51) is provided with two rod recesses (75) which are disposed opposite one another, and two exhaust-ports (33, 63) which are disposed opposite one another, each of the rod recesses being provided with a respective rod, the rotor having two seals (76) which are disposed opposite one another. 12. An underwater excavation apparatus as claimed in claim 6, wherein the at least one drilling motor (310a; 310b; 310c) comprises two drilling motors (20, 50) arranged with their respective rotors (23, 53) connected together each motor comprising a stator (21, 51) and a rotor (23, 53) rotatably mounted in the stator, the stator being provided with a rod recess (75) and an exhaust port (33, 53) the rotor being provided with a rotor channel (27, 57) and at least one channel (28, 58) for conducting motive fluid from the rotor channel to a chamber between the rotor and the stator, the rod recess being provided with a rod (71) which, in use, forms a seal between the stator and the rotor. 13. An underwater excavation apparatus as claimed in claim 12, wherein the drilling motors (20, 50) are connected in parallel or in series. 14. An underwater excavation apparatus as claimed in claims 12 or 13, wherein the drilling motors (20, 50) are arranged so that, in use, one drilling motor operates out of phase with the other. 15. An underwater excavation apparatus as claimed in any preceding claim, wherein the impellers (335a; 335b; 335c; 340a; 340b; 340c) are driven by means of a gearbox or by exploitation of the opposing reactive torque on a drive body of the motor. 16. An underwater excavation apparatus as claimed in claim 15, wherein the reactive torque upon the motor body is utilised, at least one impeller is connected to an output shaft of said motor, while at least one other impeller may be connected to the motor body. 17. An underwater excavation apparatus as claimed in claim 1, wherein the impellers are driven by a pair of motors (20, 50) operating in opposite directions. 18. An underwater excavation apparatus as claimed in any preceding claim, wherein the underwater excavation apparatus further comprises an agitator device having mechanical disturbance means and fluid flow disturbance means. 19. An underwater excavation apparatus as claimed in any preceding claim, wherein in use the underwater excavation apparatus is suspended from a surface vessel or mounted upon a sled of the type currently known for use in subsea excavation operations. 20. An underwater excavation apparatus as claimed in claim 4, wherein the outlets (373a; 373b; 373c) are each inclined substantially 45 degree  from the axis extending from the outlet. 21. An underwater excavation apparatus comprising a hollow body (310a; 310b; 310c) having a pair of inlets (371a; 371b; 371c) communicating with an outlet (373a; 373b; 373c), at least one pair of impellers (335a; 335b; 335c, 340a; 340b; 340c) rotatably mounted in the hollow body and means for driving the impellers, the inlets being substantially symmetrically disposed around an axis extending from the outlet, wherein the inlets are not horizontally opposed to one another.