Underwater power generator with dual blade sets

Abstract

A power generation apparatus for generating power from water flows is described. The power generation apparatus includes: a generator; a first blade set operatively mounted to the generator for rotation in a selected direction in response to flowing water from a selected direction; a second blade set operatively mounted to the generator for rotation and operatively connected to the first blade set, the second blade set being disposed coaxially with, and downstream of or in a wake zone of, the first blade set; wherein the generator is adapted to be driven by at least one of the blade sets, the generator being disposed generally coaxially between the first and second blade sets.

What is claimed is: 
     
         1 . A power generation apparatus for generating power from water flows, the power generation apparatus, comprising:
 a generator,   a first blade set operatively mounted to the generator for rotation in a selected direction in response to flowing water from the selected direction; and   a second blade set operatively mounted to the generator for rotation, the second blade set being disposed coaxially with, and at least one of downstream of or in a wake zone of, the first blade set, the second blade set being operatively coupled to the first blade set,   the generator configured to be driven by at least one of the first blade set or the second blade set, the generator further being disposed substantially coaxially between the first blade set and the second blade set and wherein the first and second blade sets are operatively coupled together.   
     
     
         2 . The power generation apparatus of  claim 1 , wherein the second blade set rotates in the same direction as the first blade set when the first blade set rotates in the selected direction. 
     
     
         3 . The power generation apparatus of  claim 1 , further comprising:
 at least one of a clutch or braking arrangement configured to at least one of (1) selectively uncouple or (2) operatively disconnect the first blade set from the second blade set.   
     
     
         4 . The power generation apparatus of  claim 1 , further comprising a braking apparatus configured to inhibit rotation of at least one of the first blade set or the second blade set. 
     
     
         5 . The power generation apparatus of  claim 1 , further comprising:
 a braking arrangement, the braking arraignment being a fail-safe mechanism.   
     
     
         6 . The power generation apparatus of  claim 1 , wherein the first blade set and the second blade set are each mounted on a rotor for rotation, the rotor including a rotor shaft. 
     
     
         7 . The power generation apparatus of  claim 6 , further comprising:
 a gearbox configured such that a rotation speed of the rotor shaft is increased via a gearbox output shaft to increase a speed of a generator rotor.   
     
     
         8 . The power generation apparatus of  claim 1 , wherein the first blade set and the second blade set each directly drive the generator and are mounted on a common rotor shaft so that the first blade set and the second blade set rotate at the same rate. 
     
     
         9 . The power generation apparatus of  claim 8 , wherein a plurality of blades from the first blade set are staggered relative to a plurality of blades from the second blade set. 
     
     
         10 . The power generation apparatus of  claim 1 , wherein an angle of attack of a blade from at least one of the first blade set or the second blade set is fixed. 
     
     
         11 . The power generation apparatus of  claim 1 , wherein an angle of attack of a blade from at least one of the first blade set or the second blade set is variable. 
     
     
         12 . A power generation apparatus for generating power from water flows, the power generation apparatus, comprising:
 a generator,   a first blade set operatively mounted to the generator for rotation in a selected direction in response to flowing water from a selected direction;   a second blade set operatively mounted to the generator for rotation, the second blade set being disposed coaxially with, and at least one of downstream of or in a wake zone of, the first blade set, the second blade set being operatively coupled to the first blade set; and   at least one of a clutch or braking arrangement configured to at least one of (1) selectively uncouple or (2) operatively disconnect the first blade set from the second blade set,   the generator configured to be driven by at least one of the first blade set or the second blade set, the generator further being disposed substantially coaxially between the first blade set and the second blade set and wherein the first and second blade sets are operatively coupled together.