Improvements In and Relating To Underwater Excavation Apparatus

Abstract

An excavation apparatus (5), such as an underwater excavation apparatus and/or a controlled flow excavation apparatus, comprises a rotor (10) comprising a plurality of first rotor blades (12) and a plurality of second rotor blades (14). The second rotor blades are provided between adjacent pairs of first rotor blades. The first rotor blades (12) define a plurality of primary rotor blades of the rotor (10). The second rotor blades (14) define a plurality of secondary, splitter, rotor blades of the rotor (10).

What is claimed: 
     
         1 . An underwater excavation apparatus, comprising:
 a housing comprising:
 at least one inlet; and 
 an outlet; 
   a rotor disposed in the housing;   a stator disposed in the housing;   wherein the rotor comprises a plurality of first rotor blades and a plurality of second rotor blades,   wherein the first rotor blades comprise or define primary rotor blades of the rotor,   wherein the second rotor blades are each provided between a pair of adjacent first rotor blades and comprise secondary, splitter, rotor blades the rotor, and   wherein a leading edge of one or more of the second rotor blades commences part way along a length of an adjacent first rotor blade.   
     
     
         2 . (canceled) 
     
     
         3 . An excavation apparatus as claimed in  claim 1 , wherein the leading edge of said one or more second rotor blades commences at 35% to 45% along the length of the adjacent first rotor blade, e.g. 38% measured at a bub and 42% measured at the housing. 
     
     
         4 . An excavation apparatus as claimed in  claim 1 , wherein at least one of:
 a distance between and/or an area of a flow path between adjacent first and second rotor blades increases along the length of the respective first and second rotor blades;   a distance between and/or an area of a flow path between adjacent second rotor blades increases along the length of the respective second rotor blades;   a distance between and/or an area of a flow path between adjacent primary rotor blades increases along the length of the respective primary rotor blades.   
     
     
         5 . An excavation apparatus as claimed in  claim 1 , wherein a height of one or more of the first rotor blades and/or the second rotor blades reduces along a length of the respective first and/or second blades. 
     
     
         6 . (canceled) 
     
     
         7 . (canceled) 
     
     
         8 . (canceled) 
     
     
         9 . An excavation apparatus as claimed in  claim 1 , wherein at least one of:
 the rotor is provided proximal to the at least one inlet;   the rotor comprises a first body, wherein the first and second rotor blades are disposed on the first body, and wherein optionally the first body comprises a first cone member, and/or   an apex of the rotor faces the at least one inlet.   
     
     
         10 . An excavation apparatus as claimed in  claim 1 , wherein at least one of:
 the plurality of first rotor blades comprise impeller blades;   the plurality of first rotor blades comprise aerofoil blades;   the plurality of second rotor blades comprise aerofoil blades.   
     
     
         11 . (canceled 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . (canceled) 
     
     
         15 . An excavation apparatus as claimed in  claim 1 , wherein the rotor has a rotor rotation axis. 
     
     
         16 . (canceled) 
     
     
         17 . An excavation apparatus as claimed in  claim 15 , wherein, in use, flow of fluid past or across the rotor is at a first angle a from the rotor rotation axis,
 and wherein optionally the first angle a diverges away from the rotor rotation axis in a direction away from at least one of the inlets and towards the outlet.   and wherein further optionally the first angle α is in the range of 55° to 75°, e.g. 65 °.   
     
     
         18 . (canceled) 
     
     
         19 . (canceled) 
     
     
         20 . An excavation apparatus as claimed in  claim 1 , wherein the housing comprises an axis, e.g. longitudinal axis,
 and wherein optionally at least one of:   the rotor is arranged coaxially upon or with the axis of the housing.   the stator is arranged coaxially upon or with the axis of the housing   the outlet is substantially coaxial with the axis of the housing; and/or   the housing is circumferentially/rotationally symmetrical about the axis of the housing.   
     
     
         21 . (canceled) 
     
     
         22 . An excavation apparatus as claimed in  claim 1 , wherein the stator comprising a plurality of first stator blades,
 and wherein optionally the plurality of first stator blades comprise aerofoil blades.   
     
     
         23 . An excavation apparatus as claimed in  claim 22 , wherein the stator comprises a plurality of second stator blades,
 and wherein optionally the plurality of second stator blades comprise aerofoil blades.   
     
     
         24 . (canceled) 
     
     
         25 . (canceled) 
     
     
         26 . An excavation apparatus as claimed in  claim 1 , wherein at least one of:
 the stator is provided proximal to the outlet of the housing;   the stator is provided between the rotor and the outlet   the stator comprises a second body, wherein optionally the second body of the stator comprises a second cone member;   an apex of the stator faces the outlet.   
     
     
         27 . (canceled) 
     
     
         28 . An excavation apparatus as claimed in  claim 23 , wherein:
 the first stator blades comprise a plurality of primary stator blades;   the second stator blades comprise a plurality of secondary, splitter, blades; and   one or more of the second stator blades is provided between a pair of adjacent first stator blades.   
     
     
         29 . An excavation apparatus as claimed in  claim 23 , wherein at least one of: a leading edge of one or more of the second stator blades commences part way along, e.g. 45% to 55% along, a length of an adjacent first stator blade;
 a height of one or more of the second stator blades reduces along a length of the respective second stator blade;   a distance between and/or an area of the flow path between adjacent first and second stator blades decreases along the length of the respective first and second stator blades;   a distance between and/or an area of the flow path between adjacent second stator blades decreases along the length of the respective second stator blades.   
     
     
         30 . An excavation apparatus as claimed in  claim 22 , wherein a distance between and/or an area of the flow path between adjacent first stator blades decreases along the length of the respective first stator blades. 
     
     
         31 . An excavation apparatus as claimed in  claim 1 , wherein the stator is coaxial with the rotor. 
     
     
         32 . (canceled) 
     
     
         33 . An excavation apparatus as claimed in  claim 15 , wherein in use, flow of fluid past or across the stator is at a second angle β from the rotor rotation axis,
 wherein optionally the second angle β converges towards the axis in a direction away from the at least one inlet and towards the outlet. 
 and wherein further optionally the second angle β is in the range of 55° to 75°, e.g. 65°. 
 
     
     
         34 . (canceled) 
     
     
         35 . (canceled) 
     
     
         36 . (canceled) 
     
     
         37 . (canceled) 
     
     
         38 . (canceled) 
     
     
         39 . (canceled) 
     
     
         40 . An excavation apparatus as claimed in  claim 1 , wherein at least one of:
 one or more of the inlets are provided on or at a side or sides of the housing;   one or more of the inlets is provided on or at an end of the housing;   one or more of the inlets are provided around, e.g., circumferentially or peripherally around, the housing;   one or more of the inlets are provided at a non-zero angle, e.g., perpendicularly or substantially perpendicularly, to the outlet;   one or more of the inlets are provided near or adjacent an end of the housing; and/or   one or more of the outlets are provided on or at another end of the housing   
     
     
         41 . An excavation apparatus as claimed in  claim 20 , wherein at least one of:
 one or more of the inlets are inclined and/or offset from the axis of the housing;   one or more of the inlets are provided perpendicularly or substantially perpendicularly to the axis of the housing;   one or more of the inlets are provided non-parallel to the axis of the housing;   one or more of the outlets are provided on and/or parallel to the axis of the housing.   
     
     
         42 . (canceled) 
     
     
         43 . (canceled) 
     
     
         44 . An excavation apparatus as claimed in  claim 1 , 
     
     
       wherein the apparatus is adapted to provide and/or direct a flow of water at a pressure of 200 KPa to 400 KPa and/or a volume flow of 0.5 m 3 /s to 4 m 3 /s. 
     
     
         45 . An excavation apparatus as claimed in  claim 1 , wherein there is provided a fluid flow path or passage extending from the at least one inlet to the outlet. 
     
     
         46 . (canceled) 
     
     
         47 . (canceled) 
     
     
         48 . An excavation apparatus as claimed in  claim 45 , wherein the fluid flow path comprises:
 a first section;   a second section;   a third section; and/or   a fourth section.   
     
     
         49 . An excavation apparatus as claimed in  claim 48 , wherein at least one of:
 the first section extends from the at least one inlet;   the second section contains at least part of the rotor;   the third section contains part of the stator;   the fourth section extends to the outlet.   
     
     
         50 . (canceled) 
     
     
         51 . An excavation apparatus as claimed in  claim 48 , wherein at least one of:
 the second section diverges away from an axis, e.g. longitudinal axis, of the housing; and   the third section converges towards an axis, e.g. longitudinal axis, of the housing.   
     
     
         52 . An excavation apparatus as claimed in  claim 45 , wherein the fluid flow path comprises:
 a first portion, e.g. first inlet portion, which is provided at or adjacent the one or more inlets;   a second portion, e.g. second inlet portion, which extends or continues from the first portion,   a third portion, e.g. rotor portion, which extends or continues from the second portion:   a fourth portion, e.g. intermediate portion, which extends or continues from the third portion,   a fifth portion, e.g. stator portion, which extends or continues from the fourth portion,   a sixth portion, e.g. first outlet portion, which extends or continues from the fifth portion: and/or   a seventh portion, e.g. second outlet portion, which extends or continues from the sixth portion, said seventh portion being provided at or adjacent the outlet.   
     
     
         53 . An excavation apparatus as claimed in  claim 52 , wherein at least one of:
 said first portion converges towards an axis of the housing, e.g., at a non-zero angle, e.g., between 0° and 90°, 45°, and 90°, or at 90°,   said first portion is substantially horizontal, in use, and/or perpendicular to an axis of the housing;   said first portion is substantially straight;   said second portion is curved, bent, arcuate and/or convex relative to an axis of the housing;   said third portion is substantially straight, is coincident with or contains at least a part of the rotor,   said third portion diverges away from the axis of the housing, e.g., in a flow direction from the inlet to the outlet, e.g., at an angle α of 55° to 75°, e.g., 65°   said fourth portion is curved, bent, arcuate and/or concave relative to the axis of the housing;   said fifth portion is substantially straight, is coincident with or contains at least a part of the stator,   said fifth portion converges towards the axis of the housing, e.g., in a flow direction from the inlet to the outlet, e.g., at an angle β of 55° to 75°, e.g., 65°; and/or   said sixth portion is curved, bent, arcuate, and/or convex relative to the axis of the housing.   
     
     
         54 . An excavation apparatus as claimed in  claim 1 , wherein:
 in a first mode of operation, which optionally comprises an excavation mode, the outlet faces an area to be excavated, and in such mode the one or more inlets are provided above, e.g., directly above, the outlet; and/or   in a second mode of operation, which optionally comprises a suction mode, the one or more inlets are provided proximal to an area which has been excavated, and in such mode the one or more inlets are provided below, e.g., directly below, the outlet.   
     
     
         55 . An excavation apparatus as claimed in  claim 1 , wherein at least one of:
 an inside of the housing converges from the at least one inlet towards the rotor;   an inside of the housing diverges from an inlet end of the rotor towards an outlet end of the rotor.   an inside of the housing converges from the stator towards the outlet.   
     
     
         56 . (canceled) 
     
     
         57 . An excavation apparatus as claimed in  claim 1 , wherein at least one of:
 the outlet is substantially coaxial with the rotor,   the outlet is substantially coaxial with the stator.   
     
     
         58 . (canceled) 
     
     
         59 . (canceled) 
     
     
         60 . An excavation apparatus as claimed in  claim 1 , wherein:
 the excavation apparatus comprises means or an arrangement for dampening reactive torque on the excavation apparatus caused by rotation of the rotor, in use,   and wherein optionally at least one of;   the torque dampening means comprise or include anti-rotation vanes; and/or   the torque dampening means does not comprise a second rotor, such as a second rotor configured to counter-rotate relative to the rotor.   
     
     
         61 . (canceled) 
     
     
         62 . (canceled) 
     
     
         63 . (canceled) 
     
     
         64 . (canceled) 
     
     
         65 . An underwater excavation system or tool, comprising at least one underwater excavation apparatus according to  claim 1 . 
     
     
         66 . A method of underwater excavation, the method comprising:
 providing at least one underwater excavation apparatus according to  claim 1 ; and   excavating an underwater location, using said excavation apparatus.