Prime-mover dynamo plants – Tide and wave motors
Patent
1996-07-09
1998-06-23
Stephan, Steven L.
Prime-mover dynamo plants
Tide and wave motors
290 42, 290 43, 60398, 60497, 60505, F03B 1312
Patent
active
057708932
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a wave energy devise for abstracting energy from a wave in a fluid. Particularly but not exclusively the device can be used in the offshore seaboard or on inland fresh water lakes or even in the deeper ocean.
There has been much research into the characteristics of waves. In an idealised wave situation there is a level below the mean fluid level below which the fluid is relatively undisturbed. This level is known as the effective wave base.
According to the present invention there is provided a wave energy device comprising a tube adapted to float upright in liquid with the lower end of the tube generally disposed below the effective wave base of the liquid and open to the liquid, and means for harnessing power from the changing fluid level in the tube relative to a datum on the tube.
Preferably there is provided a float arrangement associated with the tube and a ballast arrangement associated with the tube to assist the floating of the tube.
It is a preferred feature that the power harnessing means comprises a turbine rectifier which, in use, rotates in the same direction regardless of the through flow of liquid or gas.
Conveniently the turbine rectifier is mounted at the upper end of the tube and the turbine rectifier may also operate to atmosphere. Alternatively the turbine rectifier may operate into a plenum chamber.
Preferably the upper end of the tube is covered with an inverted cup member, the periphery of which extends into the fluid. When acted upon by a peaking wave, the fluid forces its way up the inside of the cup member which movement complements relative dropping of the fluid level in the tube and vice versa when the device is in the wave trough.
In a preferred arrangement the cup member is provided with a one way valve member which vents the inside to atmosphere if, during use, the pressure inside the cup member falls below atmospheric.
It is a preferred feature that the float arrangement comprises a float attached to the tube and/or a float attached to the cup member.
Preferably the tube has a constant cross section along a substantial proportion of its length.
In a preferred embodiment the tube may comprise an assembly of pipes of different lengths, at least one pipe extending below the effective wave base, thereby to increase the range of wave frequencies to which the device way respond.
The assembly may comprise a plurality of longitudinally extending radial segments of the tube, each radial segment being a pipe. Alternatively, the tube may comprise one or more bundles of individual pipes. In a further alternative the tube may comprise concentric pipes.
If the assembly comprises concentric pipes they may be in parallel, each having individual access to the water. Alternatively, the concentric pipes may form an annular continuous passage, thereby arranging the pipes in series.
In another embodiment of the invention the tube may be helical, or may comprise a plurality of intertwined helical tubes.
In yet another embodiment of the invention the tube may comprise one or more pipes having closable apertures at intervals in their side walls.
In another embodiment one or more of the pipes may be extendible.
In another embodiment, the cup 31 may be of cylindrical form, the space between the outer side of the tube and the inner side of the cup being divided vertically into segments formed by a number of interstitial walls extending above and below a lower rim of the cup.
In another embodiment the cup may be provided with a flange around its lower rim.
In another embodiment the cup may be of truncated spherical form. A toroidal float collar may be fixed to the lower rim of the cup. A collar float may be positioned around the tube.
An upper part of the cup may be of rigid construction and the lower part may be a flexible or semi-rigid skirt. The skirt may be provided with floats.
The device may include means for monitoring the wave spectrum of the water and means for controlling the lengths of said one or more extendible pipes, or means for controlling the opening a
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Ponomarenko Nicholas
Stephan Steven L.
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