A propulsion assembly for a marine vessel

Abstract

Invention relates to a thruster assembly for a marine vessel including a body including a duct having a longitudinal axis, and a first end and a second end, a support structure for a propeller including a propeller shaft at a centre line of the duct, a propeller, positioned into the duct and being attached to the propeller shaft, wherein the propeller including at least three blades and a boss which is supported to the shaft, and further a circular rim to which radial ends of the propeller blades are attached, wherein a circumferential slot is provided, opening inside the duct between the first end and the second end, into which slot the circular rim is arranged to extend radially, and at least one gas inlet arranged to open into the slot. Invention relates also to a transverse tunnel thruster and a steerable azimuthing thruster provided with the thruster assembly.

1 . A propulsion assembly for a marine vessel, comprising:
 a body including a duct having a longitudinal axis, and a first end and a second end,   a support structure for a propeller comprising including a propeller shaft at a centre line of the duct;   a propeller, positioned into the duct and being attached to the propeller shaft, wherein the propeller comprising includes at least three blades and a boss which is supported to the shaft, and a circular rim to which radial ends of the propeller blades are attached; wherein:   a circumferential slot is provided, opening inside the duct between the first end and the second end, into which slot the circular rim is arranged to extend radially;   
       and wherein the assembly includes:
 at least one gas inlet arranged to open into the slot. 
 
     
     
         2 . A propulsion assembly according to  claim 1 , wherein a space is arranged radially between a bottom of the slot and outer surface of the rim, and wherein the at least one gas inlet is arranged to open into the space. 
     
     
         3 . A propulsion assembly according to  claim 2 , comprising:
 one gas inlet is arranged to open into the space at its lowermost position.   
     
     
         4 . A propulsion assembly according to  claim 1 , wherein the slot is formed to the body by a radially inwardly extending circumferential projection forming the side walls of the circumferential slot. 
     
     
         5 . A propulsion assembly according to  claim 4 , wherein the projection comprises:
 a first fairing at a first side of the propeller and a second fairing at a second side of the propeller having the slot between the fairings.   
     
     
         6 . A propulsion assembly according to  claim 4 , wherein the projection comprises:
 a first axial end and a second axial end, and an inner diameter of the projection is substantially equal to inner diameter of the duct at the first axial end, an outer diameter of the projection is substantially equal to inner diameter of the duct at its first and second ends, and the inner diameter of the projection at its second axial end is less than outer diameter of the circular rim.   
     
     
         7 . A propulsion assembly according to  claim 1 , wherein 1-4 gas inlets are arranged to open into the slot. 
     
     
         8 . A propulsion assembly according to  claim 1 , wherein the assembly comprises:
 more than four gas inlets arranged to open into the slot.   
     
     
         9 . A propulsion assembly according to  claim 1 , wherein the assembly comprises:
 a circumferentially extending gas plenum in connection with the body provided with a plurality of substantially evenly distributed gas inlets arranged to open into the slot.   
     
     
         10 . A propulsion assembly according to  claim 1 , wherein the assembly comprises:
 evenly distributed gas inlets, having an angle (A) of 5-30 degrees between the gas inlets.   
     
     
         11 . A propulsion assembly according to  claim 9 , wherein the gas plenum circumscribes the duct. 
     
     
         12 . A propulsion assembly according to  claim 1 , wherein the propeller is provided with a rim drive. 
     
     
         13 . A propulsion assembly according to  claim 12 , wherein the propeller is provided with an electric motor wherein the rim comprises:
 a rotor part of the motor and the body of the duct is provided with a stator part of the motor.   
     
     
         14 . A propulsion assembly according to  claim 12 , wherein the propeller is provided with a mechanical rim drive. 
     
     
         15 . A propulsion assembly according to  claim 1 , wherein the propeller shaft is a driven shaft. 
     
     
         16 . A propulsion assembly according to  claim 12 , wherein the propeller shaft is a non-driven shaft. 
     
     
         17 . A propulsion assembly according to  claim 1 , wherein the slot is formed to the duct as an indent from a level of the inner wall of the duct. 
     
     
         18 . A propulsion assembly according to  claim 1 , wherein the propulsion assembly is a transverse tunnel thruster, wherein the duct of the propulsion assembly is a straight tube. 
     
     
         19 . A propulsion assembly according to  claim 1 , wherein the propulsion assembly is a shaft line propulsion system, wherein the body of the duct of the propulsion assembly is rigidly attached to a hull of a vessel and the shaft extends via a stern tube through a hull of a vessel. 
     
     
         20 . A propulsion assembly according to  claim 1 , wherein the propulsion assembly is a steerable azimuthing thruster wherein the body comprises:
 a nozzle duct and the boss of the propeller is connected to the shaft in a support structure, the support structure extending radially from the shaft for coupling the azimuthing thruster to a vessel in rotatably manner.