GB2164097A - Extracting power from waves - Google Patents

Abstract

An hydraulic wave power generator comprises an immersed float (22) which is stabilised by a counterweight (19) and is rocked to and fro by the action of surface waves on a paddle (30) mounted upon the float (22). Several floats (22) may be mounted in a frame which is anchored to the sea bed. An electromechanical generator may be driven by the float(s) through a unidirectional mechanical transmission, details about which are disclosed (Figs. 1a and 1b : not shown). The transmission includes a ratchet assembly (12), energy storage means in the form of a spring assembly (14), a drive gear ring (43) and a pinion (42). <IMAGE>

Description

SPECIFICATION Hydraulic wave power generator This invention relates to hydraulic wave power generators and is particularly concerned with a mechanical to an electrical conversion device to transfer wave power or energy to electrical power.

This topic is the subject of much contemporary research and development and multitude of proposals for efficiently and effectively utilizing the energy of wave and tidal movement as a source of usable power. In this regard both the rise and fall of the wave surface is desirably registered.

Commonly, such devices employ entrained floats responding to net local surface wave movement and a variety of means of conversion of mechanical wave movement into electrical power, including mechanical and hydraulic systems.

The central problem for such devices is in effectively registering, capturing and transferring the random and regular components of reciprocating motion, and thus associated energy and power of the constantly changing sea surface level associated with wave formation, passage and decay.

For such applications it is desirable to have a generator unit which is simple and reliable and, if it is to be incorporated in the float, relatively light weight, and one in which there is a relatively efficient conversion of energy i.e. responding to the full wave motion for various wave sizes and wave cycles and which is capable overall of generating sufficient energy for the installation to be economic.

This latter aspect may dictate a multiple unit arrangement, rather than one large individual generator and this poses a limitation upon the individual uinits themselves-i.e. they must be able to be coupled together in a simple, reliable and straightforward manner, with minimal friction losses and must be individually capable of generating a suitable amount of electric power, which when combined with the output from the other units will be of a suitable amount and character for practical usage.

Thus fluctuations in output should be kept to a minimum and this imposes a constraint upon the number, disposition and layout of individual generator units and the manner of their coupling together.

It is envisaged that reliability, simplicity of design and thus overall cost-effectiveness will be promoted by using straightforward and mechanical couplings rather than complex fluid couplings.

The present invention is concerned to provide a hydraulic wave power generator or energy converter which relies upon conventional mechanical construction principles and is thus simple, rugged and reliable and yet may readily be extended into a multiplicity of interconnected units.

Accordig to the invention there is provided an hydraulic wave power generator comprising an entrained sealed float housing (22) for flotation immersion in a hydraulic fluid medium under surface motion and arranged to react thereto, a stabilizer or counterweight (19) for said float (22) to bias it towards a reference position, a paddle (30) mounted upon and movable with said float (22) and disposed to react to fluid surface (38) movement, a movement transfer linkage for said float paddle (30) and disposed to react to bidirectional reciprocatory movement thereof and to translate it to unidirectional movement, an electro-mechanical generator connected to said linkage and arranged to generate electric power from the relative movement of said float paddle, and said liquid surface.

Such an arrangement registers the entire wave movement, since the return of each unit from its displaced position is achieved automatically by the restoration action of the stabilizer under the influence of gravity. In this way a reciprocating or double-action drive is achieved.

A spring-loaded ratchet mechanism readily lends itself to register such reciprocating action.

There now follows a description of some particular embodiments of the invention, by way of example only, with reference to the accompanying diagrammatic drawings, in which: Figure la shows a sectional view of an individual wave power generator unit; Figure ib shows a modification of the arrangement of Fig. la; Figure 2 shows an assembly of units such as shown in Fig. 1; Figure 3 shows a plan view of the assembly shown in Fig. 2 employing multiple units as shown in Figs. la and 1b; and Figure 4 shows a side elevation of the multiple unit array of Figs. 2 and 3.

Referring to the drawings, a wave power generator unit comprises a float housing 22 in the general form of a hollow, cylindrical drum closed by an end closure cover plate 21.

An internal shaft and sub-shaft assembly runs between the end cover 21 and the opposite end wall and comprises a reciprocating, spring-loaded drive ratchet arrangement for registering arcuate or angular reciprocating movement of the shaft and sub-shaft assembly in either direction and for transmitting the net effect of such movement to a generator 40.

The sub-shaft assembly comprises a series of spacers and support plates carrying various drive train gears culminating in the final drive gear ring 43 meshing with a generator drive pinion 42 of the generator 40 which is carried by a support plate 41.

The entire float housing 22 is an hermetically sealed assembly and the shaft assembly passing therethrough is sealed at opposite ends by rotating the seals 42 housed within a bearing assembly 5.

The shaft assembly is carried between opposed support frames 20 which extend to carry additional units of a multiple array as shown in Fig. 3 and Fig. 4.

The float housing is biased as a whole into a particular position by incorporation of a depending stabilizer weight 19 at one portion of the inner circumference thereof.

Any subsequent movement of the shaft assembly relative to the stationary or stabilized float housing 22 is then transmitted through the sub-shaft and gearing arrangement to the generator 40.

Movement of the float housing is achieved by a paddle 30, shown in Fig. 2 and Fig. 4, which is disposed to lie generally upright by virtue of the stable housing 22 and generally at right angles to the wave surface to be registered.

The housing 22 is immersed in a liquid whose surface is to be registered and is arranged to displace a volume of liquid such that the housing will rest at a suitable position with the paddle 30 aligned to the liquid surface and extending sufficiently at either side of the surface at rest to embrace the range of upward and downward displacement of the liquid surface.

Such movement of the liquid surface serves to displace the paddle initially laterally and because of its mounting thenceforth in an arc about the shaft assembly and the housing is thus displaced from its stabilized upright condition and the stabilized weight 19 is carried upwardly. The inherent weight of the latter tends to restore the paddle to its original undisplaced upright condition and the successive displacement restoring motion is transferred as a reciprocating movement through the shaft assembly and gearing to the generator 40.

It is thus not necessary for the paddle 30 to make a complete revolution in order to drive the generator 40.

Referring in more detail to the construction shown in Fig. 1a, the relative axial positions of the various operative members from the gears to the end seals is achieved by various spacers 2, 7, 8, 9 10 and 17. The assembly with seals is held together by spaced retainer rings 3 which co-operate with the spaced end seals 4 which are positioned about the protruding ends of the lateral shaft assembly 1, 16.

The shaft assembly 1, 16 comprises a series of shaft portions which are held axially aligned by sub-shafts such as stub-shaft 24 and which are carried by support plates such as 41 located in position by spacers 8, 9 and 10. A central spring assembly 14 within a casing is held between the opposed shaft portions and shaft assembly 16 and is successively wound up and unwound by the reciprocating angular movement of the float housing 22 about the axis of the shaft 16 under the effect of wave motion and the displacement of the returning action of the stabilizer 19. A unitary drive motion is maintained for winding the spring transmitting drive through the drive gear ring 43 held captive with the spring housing 14 to the generator pinion 42 by means of a ratchet assembly 12 which is supported by a ratchet support 13 and spacer 7 to the end cover 21 of the float housing 22.

An alternative preferred arrangement of principal elements within a generator unit is shown in Fig. 1b, wherein like reference numerals are used for corresponding parts and this will not be described separately in detail.

Fig. 2 shows how a plurality of units may be mounted generally side-by-side upon the support frame 20 and Fig. 3 shows in plan view a convenient arrangement of multiple units in a staggered off-set array so as to utilize the maximum co-operative effect of wave motion, in particular motion of successive wave crests, the spacing between units being such as to reduce any untoward influence of one unit upon the next in the direction of wave motion.

The entire assembly on the support frame 20 is held captive by an anchor cable 32 attached to the sea bed 35 as shown in Fig. 4.

Thus as successive wave crests effectively pass over the position of the support frame 20 so successive paddles are displaced and are returned to the undisplaced condition by the respective counter-weight 19 in the unit 22.

In this way a plurality of units responds to the movement of the wave surface 38.

It will be appreciated that various other dispositions and arrangements can be achieved within the scope of the invention.

Claims (7)

1. An hydraulic wave power generator comprising an entrained sealed float housing (22) for flotation immersion in a hydraulic fluid medium under surface motion and arranged to react thereto, a stabilizer or counterweight (19) for said float (22) to bias it towards a reference position, a paddle (30) mounted upon and movable with said float (22) and disposed to react to fluid surface (38) movement, a movement transfer linkage for said float paddle (30) and disposed to react to bidirectional reciprocatory movement thereof and to translate it to unidirectional movement, an electro-mechanical generator connected to said linkage and arranged to generate electric power from the movement of said float paddle, and said liquid surface.

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2. An hydraulic generator as claimed in Claim 1, wherein said paddle is biased by its float mounting to lie generally upright and thereby to respond to relatively horizontal surface hydraulic fluid movement.

3. An hydraulic generator as claimed in either of the preceding Claims wherein said float housing is semi-submersible.

4. An hydraulic generator, as claimed in any of the preceding Claims, incorporating an energy storage device, such as a mechanical winding spring, operatively connected between said linkage and said generator in order to store, release and even out the transfer of energy from the mechanical power input to the electrical power output.

5. An hydraulic generator comprising a plurality of interconnected hydraulic generators as claimed in any of the preceding Claims.

6. A multiple hydraulic generator, as claimed in any of the preceding Claims, comprising three or more inter-coupled units arranged in a laterally and longitudinally offset array for longitudinal and lateral dynamic stability.

7. An hydraulic generator substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.