Arrangement in wave energy recovery system

1. A wave energy recovery system comprising:

a wing element hinged on its one edge to make a reciprocating motion in response to kinetic energy of waves or tidal currents;

a wave energy recovery device;

a connection rod imparting the reciprocating motion of said wing element to said wave energy recovery device;

said wave energy recovery device including,

a protective housing having housing walls, and

a hydraulic cylinder provided in the protective housing and provided with a piston operably connected to said connection rod for actuation thereby,

said housing walls of said protective housing protecting said hydraulic cylinder from exposure to seawater;

said connection rod extending through a first housing wall; and

a bellows seal surrounding the connection rod as it extends though the first housing wall, the bellows seal sealing the contents of said housing from exposure to said seawater including,

an outer bellows sealingly and fixedly connected at a first end to said connection rod outside said protective housing and at a second end to said first housing wall, and

an inner bellows sealingly and fixedly connected at a first end to the connection rod inside said protective housing and at a second end to said first housing.

2. The wave energy recovery system according to claim 1 , wherein the hydraulic cylinder of said wave recovery device has a cylinder space of alterable volume defined by the hydraulic cylinder and associated piston, the cylinder space including first and second alterable volumes formed by said cylinder on opposed sides of the piston,

said connection rod penetrating both of said first and second alterable volumes of the hydraulic cylinder with the piston located intermediate thereto,

hydraulic seals provided where the connection rod penetrates said hydraulic cylinder at each of aid first and second alterable volumes.

3. An arrangement in a wave energy recovery system according to claim 1 or 2 , wherein the protective housing is waterproof and protects the hydraulic seals from exposure to seawater.

4. The wave energy recovery system according to claim 2 , wherein the housing includes a second housing wall, the connection rod extending though said hydraulic cylinder intermediate said first and second housing walls and passing through the second housing wall, wherein a second bellows seal seals the contents of said housing from exposure to said seawater as said connection rod passes though said second housing wall,

said second bellow seal including,

a second outer bellows sealingly and fixedly connected at a first end to said connection rod outside said protective housing and at a second end to said second housing wall, and

a second inner bellows sealingly and fixedly connected at a first end to the connection rod inside said protective housing and at a second end to said second housing wall.

5. The wave energy recovery system according to claim 1 , wherein the protective housing is provided with a connection plate through which the connection rod extends, the connection plate being provided with a through hole through which said connection rod extends, a diameter of the through hole of a connection plate being bigger than the diameter of the connection rod.

6. The wave energy recovery system according to claim 1 wherein the wave recovery system is installed at an installation depth, further comprising means to keep the pressure in the bellows correct depending on the installation depth where the installation is situated.

7. The wave energy recovery system according to claim 1 , wherein the bellows are included in a bellows unit, the system further comprising a pressure regulator and control to compensate a leak from the hydraulic cylinder into the bellows units, or suction from bellows units into the hydraulic cylinder.

8. The wave energy recovery system according to claim 1 , further comprising the hydraulic cylinder equipped with the outer bellows provided at the end thereof.

9. The wave energy recovery system according to claim 1 , wherein at least one connection channel is connected between the interiors of the inner and outer bellows.