Patent ID: 7836689

Claim:
An apparatus for accumulating energy from an oscillating water column, comprising: a) a first water-cylinder having a first water piston that slides between a first position and a second position in response to oscillation of the water column; b) a first fluid-cylinder having a first fluid piston that slides between a first position and a second position in response to the first water piston, the first fluid piston being operable to compress a fluid within the first fluid-cylinder; c) a first reservoir connected to the first fluid-cylinder for accumulating compressed fluid; d) a second fluid-cylinder having a second fluid piston that slides between a first position and a second position and is operable to compress a fluid within the second fluid-cylinder; and e) a second reservoir connected to the second fluid-cylinder for accumulating compressed fluid, wherein the second fluid-cylinder is connected to receive fluid from the first reservoir and to supply the fluid at a higher pressure to the second reservoir, wherein at least one of the first water-cylinder and the first fluid-cylinder is double-acting.