Abstract

A system for converting wave energy from the sea into electrical energy, comprises a floatable assembly which, in use, is moored at sea and which is capable of internal movement in response to the action of waves. The assembly includes a hollow body mounted on a shaft and reciprocable angularly about the axis of the shaft in response to said internal movement. The body and the shaft define respective parts of a pump which also comprises a pair of spaced, opposed annular cam tracks extending around the axis of the shaft and rigidly connected to one of the pump parts defined by the body and the shaft, and at least one piston and cylinder arrangement disposed between the cam tracks and rigidly secured to the other of the pump parts so as to extend substantially parallel with the shaft axis. The cam tracks and the piston and cylinder arrangement thereby undergo relative angular movement about the shaft axis in response to wave-induced internal movement of the assembly, each of said cam tracks engaging an axially movable operating piston of said arrangement and being shaped so as to move the piston within the cylinder to displace fluid received in the cylinder in response to said relative angular movement. The system further comprises an electricity generator which can be driven in response to displacement of the fluid in the cylinder.