GB2437533A

GB2437533A - Turbine and support engagement

Info

Publication number: GB2437533A
Application number: GB0700679A
Authority: GB
Inventors: Ian Master; James Orme
Original assignee: SWANTURBINES Ltd; UWS Ventures Ltd
Current assignee: SWANTURBINES Ltd; UWS Ventures Ltd
Priority date: 2006-04-28
Filing date: 2007-01-15
Publication date: 2007-10-31
Anticipated expiration: 2027-01-15
Also published as: GB0608367D0; GB0700679D0; GB2437533B

Abstract

A turbine (10, figure 1) and support (2, figure 1) there for comprise complimentary male and female engaging portions (12, figure 1), 8 such that when the turbine (10) is lowered onto the support (2), the male and female portions (12), 8 contact, thereby providing an operational engagement there between. The female portion 8 may comprise a generally cone shaped socket. Spacing means 22 may be provided on the male portion (12) to aid location into the female portion 8, the spacing means 22 preferably being made of a compressible rubber. The male portion may comprise a rotatably mounted member connected to the turbine (10), bearings 24 preferably being located between the rotatably mounted member and an inner surface of the male portion (12), and preferably further still a motor 26 may be provided within the male portion (12) to rotate the turbine (10). This arrangement is intended to easily allow a submerged marine turbine (1) to be lifted from its support (2) for examination and/or repair.

Description

Locating Device The present invention relates to a system for

connecting an energy transfer means to an immovable object, and in particular for connecting a tidal stream turbine into a pre-installed support structure on the sea bed.

With the drive to harness energy sources as alternatives to fossil fuels, there is a large amount of interest in ways to harness energy from new sources such as the sun, wind and sea. Whilst use of solar energy is becoming more and more accessible, and wind turbines continue to be erected, the problems with harnessing tidal power or energy from running water presents numerous additional challenges. There are environmental issues associated with tidal power, especially with floating or surface arrangements which obscure views and are deemed by some to be detrimental to sea life. Additionally, there is the added difficulty with the marine environment which is particularly harsh, with extremes of weather and saltwater and some marine life.

It has been envisaged that turbines may be planted onto the sea bed which removes the apparent eyesore, allowing a large number of turbines to be positioned in optimum tidal areas without being generally visible. However, this provides difficulties in that the mechanisms by which the turbines are connected to the sea bed must be able to withstand severe weather conditions. Known arrangements may be attached to the sea bed, however when maintenance is required, divers must be employed to carry out any inspections required and repair necessary which is both costly and inconvenient. The present invention aims to overcome these problems.

According to the present invention, there is a turbine and support for fixing to the ground, said turbine and support comprising complementary male and female engaging portions such that when the turbine is lowered onto the support, the male and female portions contact thereby providing an operational engagement therebetween.

The advantage of such an arrangement is that when inspection or repair is required, the support means and turbine may be lifted from the base structure with little or no skill or expertise, and lifted onto, for example, a boat. If necessary, the active turbine may be taken to a suitable location for examination andlor repair. Additionally, when locating or removing the turbine from the support, divers or motonsed means will not be required to release the turbine from the support, reducing costs associated with service, which can be substantial in such a harsh environment. Operational engagement' is defined through this specification and within the claims as being in a fit state for use without further assembly.

Preferably, the female engaging portion comprises a socket, the internal configuration of the socket being generally cone shaped, the greatest cross sectional area of the cone being at the rim of the socket. Even more specifically, the internal configuration of the socket has a decreasing diameter from the rim, comprising a frustoconical, cylindrical and conical configuration respectively. The support preferably further comprises an elongate member and a base member arranged and configured to be secured to the ground. The ground may include any surface, although more specifically refer to the sea bed.

There may be further provided a spacing means on at least a portion of the outer surface of the male engaging portion, arranged and configured when in use to aid location of the male engaging portion into the female engaging portion. This allows improved engagement for misalignment tolerances. The spacing means preferably comprises a compressible material such as rubber. Alternatively, the female portion may be shaped and configured to receive the male portion in a specific orientation. An example of such a shape would be a splined configuration.

The male engaging portion preferably comprises a rotatably mounted member arranged to fixedly connect to the turbine. A set of bearings is preferably located between the rotatably mounted member and the inner surface of the male engaging portion. There may additionally be provided a motor means within said male engaging portion arranged to rotate the turbine. This is particularly useful when the turbine must be rotated within the fluid flow to optimise energy transfer.

Also, according to the present invention, there is a method of locating a turbine in position for energy transfer, comprising the steps of: -positioning a support onto the ground; and -lowering a turbine onto said support, said turbine and support comprising complementary male arid female engaging portions; such that when the engaging portion of the turbine is lowered Onto the engaging portion of the support, the male and female engaging portions operationally engage.

The present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure Ia and b is a schematic side view of the system according to the present invention, and additionally the means by which the turbine is located into position.

Figure 2 is a schematic side view of side view the base support, including the socket and plug inserted therein.

Figure 3a-g are schematic side views of seven plug arrangements showing differing motor arrangements available for location therein.

Referring to Figure la and b, there is a schematic side view of an embodiment of the present invention which shows the implementation of the present invention. The arrangement comprises a base 2, such as a steel substructure which can be installed into the desired location. The base preferably only comprises components that do not require servicing, and as such may be fixedly attached in location, such as on the sea bed. The base 2 comprises a generally flat member 4 which extends parallel to the sea bed, and an elongate member 6 extending at substantially 900 therefrom. This elongate member 6 is fixedly attached to the flat member 4, and comprises a recess (socket) 8 for receiving a turbine nacelle 10 or similar. The socket 8 is generally of increasing diameter, and in a preferred embodiment, comprises from the elongate member to upwards, a conical section, a cylindrical section and a frustoconical section. This configuration provides relatively easy location of a plug 12 onto which is mounted a turbine nacelle 10 into the base 2 as indicated in Figure Ia, in particular where currents are likely to be present. The angles of the plug 12 to socket 8 interface are chosen such that any expected combination of vertical and horizontal loads does not exceed the friction force between the interfaces such that all components remain in position.

The plug 12 is also cone shaped in the vicinity of the tip to aid installation. The outer part of the plug 12 comprises a bearing surface 14, which is a compressible material such as rubber which allows for misalignment when locating the plug 12 into the socket 8, and will also allow for manufacturing tolerances, wear, corrosion and marine growth. Additionally or alternatively, a splined arrangement may be provided between the outer surface of the plug 12, and the inner surface of the socket 8 which further resists rotation therebetween.

However, it will be appreciated that the more complex interface provided between the plug 12 and socket 8 reduces the ability for misalignment, marine growth etc. Locating shims 22 (visible with reference to Figure 2) may be used on the outer surface of the plug 12 to allow for less rigorous tolerances in the dimensions of the plug and to aid in positioning of the plug 12 in the socket 8. The inner part of the plug 12 may contain ballast which is provided to orientate the structure correctly and will act as a keel for the overall structure during transportation.

In order to locate the plug 12 into the socket 8, there is provided a lift attachment on the turbine nacelle such as a hook or loop onto which a cable may attach. Ideally, the attachment should be located directly above the plug 12 to ensure operational stability and ease of installation. A boat, for example, can then lower the nacelle and plug arrangement down into the socket 8 which is fixedly attached to the ground via the base 2.

Inside the plug 12 is provided a section that rotates relative to the plug 12 on a set of bearings 24. The degree of friction of these inner bearings 24 is significantly less than the frictional force between the plug and socket, and the turbine nacelle 10 attaches to this rotationally mounted section. This therefore enables the turbine nacelle 10 to rotate relative to the fluid flow and thus can be aligned in the water such that the optimum amount of energy may be transferred into useful energy. By housing these bearings 24 as part of the plug, the servicing is easier as the entire system may be lifted as one rather than having to employ divers to carry out servicing which is both expensive dangerous and limits in the repairs that can be carried out.

The bearing set 24 (as shown in Figures 2 and 3) are preferably water lubricated polymer bearings which have a relatively high degrees of friction, meaning that the turbine nacelle 10 will not rotate uncontrollably relative to the base. Alternatively, or in addition, there may be provided a drive system 26 which is powered and enables the turbine nacelle 10 and the base 2 to be rotated relative to each other.

Referring in particular to Figure 3 where seven alternative arrangements are shown, the drive system 26 can be a single motor (shown in Figures 3a-c) or a number of motors (shown in Figures d-g), which can in turn be electrical or hydraulic. Spur gears are driven by the motor(s) against a ring gear, or in the case of a single motor the sections are connected by a shaft. The motor(s) may incorporate a system of gears. An alternative system for rotating the turbine nacelle 10 and base 2 relative to each other could employ a series of bushes that could be moved independently to rotate about an axis in a similar manner to a folding fan.

A means to detect the rotational position of the turbine nacelle 10 relative to the base 2 could be an optical device, an electromechanical sensor, or alternatively in some applications a magnetic positioning system or similar. The inner part 28 of the plug 12 may include additional ballast material which will correctly orientate the structure to which it is connected and will act as a keel for the plug 12 during transportation.

When the device is stationary and in the desired orientation, any horizontal load on the system increases the friction limit of the inner bearings so that there is no unexpected rotation of the rotationally mounted section. One example of undesired rotational loads would be the action of waves above the system. Another would be variations in yaw and teeter on the rotor of a tidal stream turbine when in power generating conditions.

Prevention of rotation of the rotationally mounted section under small yawing forces significantly reduces fatigue loading and "fretting" effects on the motor(s) and gearing system.

When the device is stationary and not in the desired orientation, horizontal loads increase the friction as above, but it is expected that the undesired rotational loads are significant and above the friction limit of the inner bearings. In this case, the motor drive connecting the plug and moving section could be locked in place (electrically or hydraulically) to provide additional torque. One example of this scenario is a tidal stream turbine which is not oriented with the tidal stream, and there is a flow of water present.

When there are no horizontal loads on the system, the drive system can create a large torque between the moving section and the plug. This torque exceeds the friction limit of the bearings and so rotates the system mounted on the moving section relative to the base.

One example of this situation is the yawing of a tidal steam turbine at slack water.

The motors could use an hydraulic accumulator or battery system to rotate the device in the absence of an external power supply when power is not being created by the turbine system or similar device. When the turbine is running, the motor(s) can be employed to further resist any external yawing forces experienced.

A skirting/debris shroud could surround the top of the plug to prevent ingress of debris, sediment and marine life interfering with the system. In the case of a system immersed in a flowing fluid where the device is employed to align the system with the flow, the yaw motor(s) could be replaced by hydrodynamic control devices such as a long tail fin that would automatically align the system with the fluid flow.

In some configurations, it would be possible to route a power out cable through the centre of the system between the supported structure and the foundation system. It is also possible that a locking pin could be introduced to the system to prevent any rotation if desired.

The present invention has been described by way of example only, and it will be appreciated by a person skilled in the art that variations and modifications may be made to the present invention without departing from the scope of the appended claims. For example, the preferred embodiment of the present invention has been described with respect to a marine turbine, however the present invention may be easily applied to a wind turbine.

Claims

CLAIMS: I. A turbine and support for fixing to the ground, said turbine

and support comprising complementary male and female engaging portions such that when the turbine is lowered onto the support, the male and female portions contact thereby providing an operational engagement therebetween.

2. Apparatus according to claim 1, wherein the female engaging portion comprises a socket, the internal configuration of the socket being generally cone shaped 3. Apparatus according to claim 2, wherein in the greatest cross sectional area of the cone is located at the rim of the socket.

4. Apparatus according to any of claims 1 or 2, wherein the internal configuration of the socket has a decreasing diameter from the rim, comprising a frustoconical, cylindrical and conical configuration respectively.

5. Apparatus according to claim 1, wherein the support further comprises an elongate member and a base member arranged and configured to be secured to the ground.

6. Apparatus according to any preceding claim, further comprising a spacing means on at least a portion of the outer surface of the male engaging portion, arranged and configured when in use to aid location of the male engaging portion into the female engaging portion.

7. Apparatus according to claim 6, wherein said spacing means comprises a compressible material such as rubber.

8. Apparatus according to claim 1, wherein said female portion is shaped and configured to receive the male portion in a specific orientation.

9. Apparatus according to any preceding claim, wherein the male engaging portion comprises a rotatably mounted member arranged to fixedly connect to the turbine.

10. Apparatus according to claim 9, wherein a set of bearings is located between the rotatably mounted member and the inner surface of the male engaging portion.

11. Apparatus according to either of claims 9 or 10 further comprising a motor means within said male engaging portion arranged to rotate the turbine.

12. A method of locating a turbine in position for energy transfer, comprising the steps of: -positioning a support onto the ground; and -lowering a turbine onto said support, said turbine and support comprising complementary male and female engaging portions; such that when the engaging portion of the turbine is lowered onto the engaging portion of the support, the male and female engaging portions operationally engage.

13. A turbine and support arrangement as hereinbefore described with reference to the accompanying drawings.