IES86253B2 - Device and its application for converting ocean wave type energy into useful rotational energy - Google Patents

Abstract

The invention addresses the desire to harness ocean type wave energy economically with simple long lasting components which are currently mass produced. The assembly of these components in a mechanism plus some special components in a mechanism plus some special components allows for chaotic wave energy acting on a floating body to be converted into unidirectional rotational energy which can be used for power take off such as electricity generation, this power being generated on the floating body. <Figure 1a>

Description

Device and its application for converting ocean wave type energy into useful rotational energy Field of invention The invention relates to a device for converting ocean wave type energy which is chaotic into an energy which can be readily converted into electrical or other energy. More particularly combinations of the devices are described.

Background to the Invention Global wanning and the ever increasing energy demand make the renewable energy industry ever more compelling. Solar, wind and ocean energy have an ever-increasing appeal for exploitation.

Ob ject of the Invention The object of this proposed invention is to address the harvesting of ocean or lake wave energy and to address various associated problems, which include the capital cost, environmental impact, survivability in tempests and high cost of maintenance.

Capital cost The ideas in this invention attempt to address these areas insofar as the technology uses readily available engineering hardware which is in constant production and therefore competitively priced. The invention also addresses transportation from factory to site costs.

Environmental impact.

The energy conversion units are tethered and float on the sea surface protruding above sea level by about a meter and will be barely visible some distance from the shore. Their location will have to be highlighted by some system, however, for sea traffic reasons.

Survivability in tempests Survivability is a crucial area as is the whole area of safety. Some energy conversion units in this invention can be inverted and they will continue to function. Al the moving components are isolated from sea water with the exception of the tethering and power transmission connection. Extreme forces are limited by limited movement capability of the mechanism as only rotation is possible. The unit can run in extreme wave conditions.

Maintenance The design of the energy conversion units can afford to be extremely conservative since there are no weight penalties and therefore long service life of the units can be expected. Components not working in an oil bath are very slow moving. Access to the internal mechanism is through a sealed hatch. For major overhauls units can be towed easily since the draft would not exceed three meters. Sensory equipment will detect ingress of water which can be automatically pumped out.

Statements of the Invention In a first aspect of the invention, there is provided a device for converting wave energy into electrical energy, comprising: a support (a) suitable for floating on a water surface; a moveable body (b) mounted on the support and adapted for reciprocal rotational motion about a horizontal axis provided on the support, wherein the horizontal axis is substantially parallel to the water surface; and means for converting reciprocal motion of the moveable body generated by horizontal, vertical or chaotic motion of the support under wave action into unidirectional circular or rotational motion for driving an electrical generating means.

The advantage of the device of the invention is that the parts are easy to maintain, relatively cheap to manufacture and most importantly, allows the conversion of unidirectional rotary motion from chaotic motion which is substantially in one vertical plane, two such means at right angles to each other providing unidirectional rotary motion separately but in two vertical planes which are at right angles, this arrangement capable of receiving wave energy from all directions.

In a preferred embodiment, the support is made of a waterproof material. This ensures lifetime of the device is maximised and/or that the device does not inadvertently sink in use.

Suitably, the support is a housing or a container within which the moveable body is disposed. This is a preferred arrangement as surrounding the mechanism protects it from salt water corrosion, storm damage and moisture damage from water ingress. The support may be a planer shape or a rectangular, pillow shaped container or shell within which the moveable body is disposed. Arrangements where the mechanism is covered are preferred for the reasons given above.

Desirably, the support comprises at least one tethering means, which technology is readily available.

Preferably, the device of the invention comprises an electricity transmission means.

This is desirable as generated power can be transferred to electrical apparatus for direct use or to a grid.

Suitably, the high inertia mass or weight may have a mass of from about 5 to about 20 tons. The mass or weight may be a liquid filled container or concrete body.

In a particularly preferred embodiment, the movable body has a substantially cylindrical, substantially half cylindrical, substantially third cylindrical or substantially quarter cylindrical shape.

Suitably, the moveable body is mounted on the support by a horizontal shaft and bearing arrangement.

In a particularly preferred embodiment, the means for converting reciprocal motion comprises at least two chain sprocket arrangements comprising: a chain, and at least a first and a second sprocket fitted with the chain, wherein the first sprocket is rotatably connected to the moveable body for movement therewith, and wherein the at least second sprocket is unidirectional and mounted onto a drive shaft of a electricity generating means.

Suitably, the second sprocket is mounted onto the support, at a distal position removed from the first sprocket.

In a preferred embodiment, the device comprises a pair of chain sprocket arrangements laterally disposed relative to each other.

Suitably, the at least one first sprocket has a greater diameter than the at least one second sprocket.

In a preferred embodiment, the means for converting reciprocal motion comprises at least a first and second chain sprocket arrangement, which comprises a chain, and at least a first and a second sprocket fitted with the chain, wherein the first sprocket is rotatably connected to the moveable body for movement therewith, and wherein the at least second sprocket is unidirectional and mounted onto a drive shaft of a electricity generating means.

Suitably, the first chain sprocket arrangement the chain circulates around the first and the second sprocket to cause rotation of the second sprocket in one direction to operate the drive shaft.

Desirably, the second chain sprocket arrangement further comprises an idler positioned proximal to the least one second sprocket such that diversion of the chain from an upper portion of the first sprocket to the bottom of the second sprocket and onto the idler causes rotation of the at least one second sprocket in the same direction (unidirection) as that of the first chain sprocket arrangement, and wherein the idler returns the chain to the at least one first sprocket.

In an further preferred embodiment, the first chain and sprocket arrangement to drive 5 the driven shaft is as described before, the second chain and sprocket arrangement similar to the first, but driving the driven shaft with a pair of spur gears intermediate of the second sprocket and the driven shaft, the second gear driving the driven shaft unidirectionally in the same direction as the first chain and sprocket arrangement.

In a further preferred embodiment, the device if the invention further comprise biasing means which connects the moveable body to the support. This is advantageous as it allows harvesting of vertical motion and/or chaotic motion of the support. The biasing means linking the support and the moveable body means that vertical translation is converted into rotational movement of the moveable body and the advantages that arise therefrom.

Suitably, the biasing means comprises a crank and tension spring wherein the crank is mounted onto the moveable body and the spring is mounted on the support body for conversion of vertical movement of the support under wave action to reciprocal or rotation movement of the moveable body.

In a related aspect of the invention, there is provided a wave energy harvesting system comprising one or more of a device having one all or any combination of the features of the device described above, being operable in tandem. This is a desirable arrangement as it means large amount of useable energy can be generated simultaneously. Furthermore, the power generation levels will not suffer significantly if a small number of the devices fail for any reason.

In a further related aspect of the invention, there is provided for use of one or more of a device having one all or any combination of the features of the device described above, in a method of generating or harvesting electricity. Suitably, the device is used on the sea or in another environment where continuous motion would be available.

In a further preferred embodiment, there is provided a device for converting ocean or lake wave energy into electrical energy comprising a water proof housing which floats on the surface of the water and within which is mounted a shaft by means of anti friction bearings at each end, the shaft rigidly connected to a bob weight or a high inertia mass, the shaft protruding through the support bearings allowing the rigid mounting of two large chain sprockets side by side at one end of the shaft and at the other end a crank, the pinion of which has an anti friction bearing supporting the end of a tension spring, the other end of which is attached to the inside of the water proof housing, the large chain sprockets driving a driven shaft on which are rigidly connected unidirectional bearings, permitting driving of the shaft in the same direction, the outer races of which are rigidly connected to two small sprockets separately driven by the large sprockets so that rotation of one pair of large and small sprockets is in the same direction and the other pair of large and small sprockets is in the opposite direction, achieved by the chain leaving the top of the large sprocket and thereafter engaging with bottom of the small sprocket for a number of teeth from which the chain is led over an idler wheel before returning to the bottom of the large sprocket, the total combination of what has been described resulting in wave action on the outside of the waterproof housing causing tension in the chain drives to drive the driven shaft in only one direction although pitching of waterproof housing is in both directions alternately, both directions causing effort on the driven shaft consecutively, additional to this, vertical acceleration of the water proof housing causes the bob weight to rotate since the spring acting on the crank will have pulled the bob weight out of vertical, the foregoing describing one means of a number of means of creating unidirectional rotary motion from chaotic motion which is substantially in one vertical plane, two such means at right angles to each other providing unidirectional rotary motion separately but in two vertical planes which are at right angles, this arrangement capable of receiving wave energy from all directions.

Preferably, one or two mechanisms as described above may be enclosed in a substantially longitudinally pillow shaped floating body which is capable of being bolted to one or more others so that they can act as a unit. More preferably still, several mechanisms as described above may be enclosed in transport container type floating body the direction of the axis of the mechanism running along the length of or transverse to the length of the container or a mixture thereof, the containers being capable of being bolted together side by side to act as a unit. Suitably, a substantially pillow shaped floating body may be used, so shaped from any cross section in a vertical plane, and containing at least three mechanisms as described above, the heaviest portions of the mechanisms being symmetrically close to the centre.

Brief Description of the Drawings Additional features and advantages of the present invention are described in, and will be apparent from, the detailed description of the invention and from the drawings in which: Figure 1 describes the energy harvesting mechanism and a housing, Figure 2 describes the energy harvesting mechanism in better detail with optional transmission means.

Figure 3 describes the mechanism installed in a freight container type housing.

Figure 4 describes the mechanism installed in a freight container type housing.

Figure 5 describes four harvesting mechanisms installed in a housing.

Detailed Description of the Invention It should be readily apparent to one of ordinary skill in the art that the examples disclosed herein below represent generalised examples only, and that other arrangements and methods capable of reproducing the invention are possible and are embraced by the present invention.

Referring to Figure 1 and 2, a waterproof container, a support, in this case a housing (a), in which, is mounted a moveable body, in this example, a heavy bob weight (b), which in this arrangement is thick walled cylindrical shape for example, made of concrete or liquid filled tank axially mounted on a shaft (c) which is mounted on bearings (d), at each end. The bearings are mounted within the housing. The shaft protrudes through both bearings, still within the housing, allowing on one side the mounting of two large diameter chain sprockets arrangement (d) and on the other side a biasing means, in this case a crank of short radius (e), at the latter end of which is a hearing (f) to which is attached a tension spring (r), the other end of which is connected to the housing. The two sprockets on the other end of the shaft drive small sprockets (g) within which are unidirectional pall bearing units (h), such as on the rear wheel of a bicycle, the direction of free rotation when mounting both the sprockets on the driven shaft is the same. The chain (n) from one of the large sprockets drives its corresponding small sprocket in the same direction of rotation whereas the other large sprocket drives its corresponding small sprocket in the opposite direction of its rotation. This is done by connecting the chain leaving the top of the large sprocket to the bottom of the small sprocket after which the chain leaves this sprocket to go to an idler (i) from which the chain returns to the bottom of the large sprocket. The reverse rotation effect can also be achieved by connecting the chain leaving the large sprocket to the bottom of the small sprocket after which the chain leaves the top of the small sprocket to an idler wheel (i) above the large sprocket. The idlers in both cases are placed so that there ample tooth engagement between chain and corresponding sprocket. The driven shaft (j) maybe of a gearbox generator unit (k). A chain tensioning assembly (p) is also shown.

It can be seen that, if the housing is caused to pitch backwards and forwards (by wave action) about an axis parallel to the shaft of the bob weight, the inertia of the bob weight will rotate the driven shaft in one direction only. Further, if the housing is moved up and down vertically, even chaotically, the direction of rotation of the driven shaft will be the same, The crank and tension spring arrangement ensures a differential of movement between the housing and the bob weight from purely up and down wave induced forces as opposed to pitching forces. The tendency of the bob weight to resist movement causes the release of energy because of its interaction with the movement of the housing which is enforced by wave action.

If the bob weight (a) was exchanged for a fully cylindrical shape (q) this would become a rotational inertial mass which would result in the mechanism described above transferring wave energy from pitching backwards and forwards only, not up and down movement.

If the previous two paragraphs could describe the collector of the energy, there are options of how the collector can be used in different housings.

In one type of housing (Figure 1) the design shows a rectangular cross section in the plane of the axis of the bob weigh of the collector and a pillow shaped cross section at right angles to that axis. One or more collectors could be placed in such a housing In another type of housing (Figure 3 and 4) shaped and equipped for transport like a shipping container, a number of collector assemblies can be mounted with their bob weight axes running both transverse and along the length of the container. Both this type and the previous type are equipped to be bolted together so that multiple housings can act as one. Both this and that described in the previous paragraph can operate if inverted.

In another type of housing (Figure 5), four collector units are at the centre, with their bob weight shaft axes in the same horizontal plane and at right angles. The cylindrical bob weights are as close as possible to one another. On plan the shape of the housing is substantially octagonal or polygonal for more collector units and could be circular if manufacturable. A cross section of the housing looks like two saucers meeting at the lip. The bottom saucer is shaped so that the surface near the centre follows, with some clearance, the radius of the cylindrical bob weights and up to the level of the shafts supporting them, where a tethering connection is fastened. This shape allows the whole housing to pitch about a tethering means without cyclical loading on the tether. Energy from the unit is led from this connection point.

The previous three paragraphs describe housings enclosing collector units. The housings require tethering means.

All systems described above can be arranged for so called 'point' collection with a single tether suitably anchored.

A further means involves rope stretched over considerable distance to which the first two type of multiple housings can be attached side by side by means a hinged articulated framework allowing vertical and pitching movement while restraining sideways movement. The words “comprises/comprising” and the words “having/including” when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

Claims (5)

1. A device for converting wave energy into electrical energy, comprising: a support (a) suitable for floating on a water surface; a moveable body (b) mounted on the support and adapted for reciprocal rotational 5 motion about a horizontal axis provided on the support, wherein the horizontal axis is substantially parallel to the water surface; means for converting reciprocal motion of the moveable body generated by horizontal, vertical or pitching motion of the support under wave action into unidirectional circular or rotational motion for driving an electrical generating means. 10

2. The device according to any preceding claim wherein the means for converting reciprocal motion comprises a first and second chain sprocket arrangement, which comprising a chain, and at least a first and a second sprocket fitted with the chain, wherein the first sprocket is rotatably connected to the moveable body for movement therewith, and wherein the at least second sprocket is unidirectional and mounted onto a drive shaft of a electricity generating 15 means, wherein the first chain sprocket arrangement the chain circulates around the first and the second sprocket to cause rotation of the second sprocket in one direction to operate the drive shaft; and wherein the second chain sprocket arrangement further comprises an idler positioned proximal to the least one second sprocket such that diversion of the chain from an upper portion of the first sprocket to the bottom of the second sprocket and onto the idler 20 causes rotation of the at least one second sprocket in the same direction (unidirection) as that of the first chain sprocket arrangement, and wherein the idler returns the chain to the at least one first sprocket.

3. The device according to any preceding claim further comprising biasing means connecting the moveable body to the support for translation of vertical motion into rotation of the 25 moveable body, wherein the biasing means comprises a crank and tension spring wherein the crank is mounted onto the moveable body and the spring is mounted on the support body for conversion of vertical movement of the support under wave action to reciprocal or rotation movement of the moveable body.

4. A wave energy harvesting system comprising one or more of a device having the features 30 of any one of claims 1 to 3, the devices being operable in tandem.

5. A device, a system or a use substantially as hereinbefore described with reference to the accompanying description, drawings and/or examples.