GB2348465A

GB2348465A - Combination air and water turbine.

Info

Publication number: GB2348465A
Application number: GB0004146A
Authority: GB
Inventors: Peter Leonard Fraenkel
Original assignee: I T POWER Ltd
Current assignee: I T POWER Ltd
Priority date: 1999-02-24
Filing date: 2000-02-23
Publication date: 2000-10-04
Anticipated expiration: 2020-02-23
Also published as: GB2348465B; GB0004146D0; GB9904106D0

Abstract

A turbine installation includes a column/pile upstanding from a river or the sea bed to project above the water level for supporting a water current turbine 21 on that section of the column below water level 4 and a wind turbine 50 on a section of the column that is always above water level. The water turbine is axially movable relative to the mast for maintenance. Either turbine rotate about the column and may have variable pitch blades; a worm/worm wheel acting on the blade root pitch adjuster arrangement is disclosed (Figs. 2, 3). A handling crane may be fitted to the column.

Description

COMBINED WATER AND AIR TURBINES This imventon relates to water turbines and more part) cu) ar) y to turbmes arranged to be driven by the act) nn of a flow of water.

In our British Patent Application No 9706464.6 and in our British Patent No 2256011 B and our copending Application Water Current Turbine Pitch Control and Water Current Turbine Sleeve Mounting we have disclosed constructions of water drivable turbines As has been previously-nmentioned flowing water is a charactensttc of tidal, manne, estunal or river currents.

Bearing this in mind the present invention relates in particular to the use of turbines for extracting kinetic energy from flowing water for the purpose of being able to utilise such kinetic energy to produce either electricity directly or to produce rotation of a shaft for utilisation for a required purpose.

A known turbine arrangement intended for extracting kinetic energy from water currents, whether in a river or at sea, generally inclues a rotor capable of interacting with the f) ow of water in such a way that some of the energy motion of the passing mass of water produces forces on the blades of a rotor thereby producing rotation of the rotor. The rotation of the shaft is utitised to perform some useful function such as to generate electricity. Such a device is analogous in principle to the better known concept of a windmill or wind turbine which extracts kinetic energy from flowing air, except that due to the much greater density of water as compare with that of air, lower fluid flow velocities (by a factor of approximately 9) are needed to give the same power density (power per unit area of flow) so that water moving at Im/s has a similar power density (e. g., watts per square metre) as air moving at 7.5 metres/second It is also to be noted that although the basic principles involved in extracting kinetic energy from water currents are similar to those involved in the better knoxvn art of extracting kinetic energy from the wind, the actual forces involved and the practical engineering requirements for the formation of suitable installation are in most respects totally different.

In practice, tidal, marine and river currents generally have their maximum velocity near to the surface so that any device intended efficiently to intercept the kinetic energy of the currents needs to have its rotor set so that its active plane or cross section is perpendicular to the direction of water flow and as near as possible to the surface. Any such device also needs to be securely position in such manner as to resist the considerable drag forces and reaction forces associated with any interaction with large masses of moving water. In practice, the main drag force is an axial thrust in the direction of current flou due to the momentum deficit in the flow, which thrust is proportional to the area of the active rotor and the velocity squared. There is also a significant torque reaction to be resisted when a load is applied to the turbine rotor drive shaft. Furthermore, means has to be provided to convert slow rotation rotor movement produced by the water flow into a useful energy form that can be effectively transmitted from the generation location to a location at which it can be gainfully employed.

Such transmission of energy can be in the form of electricity by way of a marine cahle along the sea or river bed (or by way of overhead cables supported by pylons or potes if the installation is close to the shore or river bank) there is also the option to use the energy"on site"for the production of some portable product such as fresh water, ice, minerals extracted from the sea or hydrogen and oxygen produced by electrolysis or any other products that can be generated from energy and the local environment, any such products can be stored and collecte by an appropriate vessel, or transmitted to shore by pipeline.

For a practical mstallation there are other important factors that need to be addressed. In the case of marine applications such factors include the need to resist damage 1roi-n large waves during storms, the need to make the device risible to mmimise it as a marine hazard to shipping and the need to be able to service and repair as well as to deploy the device at sea both safely and at a minimum cost.

It is an object of the present invention to provide a turbine system that takes into account the above factors together with derivation of power from elsewhere Accordmg to a first aspect of the invention there is provided a turbine installation mctuding a water current flow turbine and an air dnvable turbine For a better understanding of the invention and to show how it may be carried into effect reference will now be made to the accompanying drawings in which Figure l schematically illustrates a first embodiment of a mountlng column ! pile for mounting a manne turbine ; Figure 2,) s a schematic wew of an embodiment of a pitch control mechanism, for a two bladed rotor, taken on the line A-A of Figure 3, Figure 3 is a schematic view of an embodiment of a pitch control mechanism taken on the line B-R of Figure 2 ; Figure 4 schematically illustrates an embodiment of a combined water current turbine and an air driven turbine, the Figure illustrating the embodiment when the turbine is immersed in water ; and Figure 5 illustrates the embodiment of Figure 1 when the turbine has been raised above the surface of the water Referring now to Figure 1 this Figures illustrate a column 1 upon which it is propose to mount a water driven turbine As will be noted the column stands m an appropriately formed hole 2 in the seabed 3. The height of the column I can be such that it is tall enough to project about the surface 4 of the surrounding water 5 what ever the state of tides or flood levels of a river. A sleeve 6 fits closely around the column and is supported on thrust pads 7 (not shown in detail). These pads arc fonned from a sea water compatible low friction material generally attached to the inside surface of the lower part of the sleeve. A rubbing ring (not shown) having non-corrodable finish is provided on the surface of the column.

A housing 8 is provided at the upper end of the column. The housing incorporates a slewing mechanism 9 schematically shown as including a main gear 10 which connects with the sleeve 7. A worm wheet) I meshes with the main gear 10. The worm wheel receives drive from a suitable drive arrangement such as a servo motor 12 A smaller diameter extension 13 is provided at the upper end of the column. This extension 13 serves as a support for a crane or other lifting device/mechanism 14 the purpose of which nvill be discussed herein after.

The vertical setting or position of the outer sleeve 7 s conlrollcd by a rack and pinion mechanism 15.'t'he rack 16 thereof is mounted to the sleeve 6 and extends vertically upwards parallel to the vertical axis of the sleeve with its upper engaging within an open-ended guide tube 17. which projects upwardly through the roof 18 of the housing The pinion 19 of the mechanism 15 is suitably mounted within the housing 8 that it is effectively positionally constrained against displacement lengthways of the column 1. An electrical control box is schematically indicated at 20.

A water current turbine unit 21 is mounted by way of a support frame 22 carried by the outer sleeve 7 whereby displacement of the sleeve 7 lengths ways of the sleeve 6 will produce corresponding length ways displacement of the turbine.

Figure 2 illustrates the turbine unit and associated outer sleeve 7 when in their raised positions. As will be seen the upper end of the rack 16 is then projecting out from the upper end of the guide tube 17.

The turbine unit inclues a main shaft 23 and associated bearings 24 winch are journaled in the body ! nacelle 25 of the turbine. A rotor assembly 26 is mounted on the main shaft 23.

The rotor can incorporate two, three, four or more blades according to operational and expected mode of use. For the purposes of Figures I and 2 it N bue presumed that the rotor assembly is provided with two blades eqmangularly spaced about the axis of the main shaft and rotor. A farmn ? 7 is provided to offer streamlining to water flow through the rotor assembly.

The main shaft is arranged to drive an electrical generator 28 though a suitab) e speed increasing gear box 29. Electrical output from the generator is fed by way of an output cable 30 which is guided upwards, conveniently, adjacent to the rack 16. The cable connects with the control box 20. The output from the control box feeds into a marine cable 31 which by way of a conduit 3 2 extending a. \) a)) y uf the column leads downwardly of the column 1 to exit therefrom at the nver or sea bed, the conduit leading to a shore or river bank location (not shown) The arrangement of the rotor unit on the rotatable sleeve 6 allows the turbine unit 26 to be yawed through a full 180 degrees to face the current when the tide changes direction. Thus, the rotor 26 can thus be always operationally faced faced into the current and can if desired be disabled.

Referring now to Figure 2, it will noted that in this Figure that the turbine unit has been released from the support cradle 22 and lifting using the crane 14.

This arrangement makes it possible to service and/or remove and replace turbine units without it being necessary to employ a so-called jack-ut barge for this purposes.

In practice it is possible to slew the crane 14 so as to facilitate the handling of any load being carried by the crane 14. It will be understood that normally the turbine unit would be released from its cradle by removal of retaining bolts atter the sleeve 7 had been raised to position on the sleeve and turbine unit above water level.

It will be appreciated that the arrangements shown in the Figures 1 to 3 and as so far described in relation to theses Figures represent a particular typical embodiment of a water turbine installation. Various variations may be made whilst achieving essentially a similar if not the same result. For example, a direct drive multi-pole generator may eventually be developed capable of rotating at the same speed as the rotor and therefore not needing a gearbox. The gearbox may be replaced by a hydraulic transmission system (using either suitable hydraulic oils or fluids or even sea water) and the generator may then be driven by a hydraulic motor either in the nacelle or even located remotely, such as above the column. In the housing on top or even remote from the installation with hydraulic transmissions pipes running along the seabed. The gearbox can incorporate the shaft bearings in some cases or it can be driven from a separately supported shaft via a coupling. The generator can be external to the nacelle for the purposes of cooling (using submersible motor/pump technology) and it may be filed with water or some other fluid to help avoid ingress of sea water.

Furthermore, it is convenient to note that a faring (not shown) could he provided on the side of the outer sleeve 7 remote from the turbine support frame, the faring being so shaped that it not only serves to streamline the column and this serve to reduce drag forces thereupon, but also, when the turbine is in the yawed position with its rotor edge facing on to the direction of water current flow CF, the drag of the faring counterbalances the drag of the rotor and the nacelle thereby to reduce tortional loads on the sleeve slewing mechanism. Whilst the construction as above so far discussed allows for the rotation of thesleeve 6 to move the turbine to a yawed non operational position it is possiblefor the need to be able to rotate the sleeve can be avoided by so constructing the rotor assembly of the turbine unit so that the rotor assembly thereof incorporates pitch control such as is used in relation to aeroplane propeller blades, for adjusting the angle of set of the blades with respect to the flowing water direction.

Referring now to Figures 2 and 3 which illustrate a two bladed rotor assemblyincorporating pitch control. As is shown in these Figures, the root 33 of a blade 34 of the rotor 26 is bolted or otherwise attached in an appropriate manner to a cylindrical body 35. The body 35 cooperates with bearings 36 set into a rotor hub 37 which is mounted to the rotor shaft 23.

The external cylindrical face of the body 35 runs in a bush 38 and emerges at the circumference of the hub 37 through seats 39 designed to prevent ingress of sea water into the hub The bodies 35 are machined with spiral teeth 40 to be able to mesh with a worm drive 41 driven via gears 42 by a servo motor 43. Said servo motor 43 can cause the pair of worm drives 41 to rotate the same distance in opposite directions, thereby causing the rotor blades to move differentially by identical amounts.

Profiles of a rotor blade 34 outboard of the roots of the blades are shown in broken lines in Figure 5 to illustrate how the blades 34 may be position to face the current in either direction or to lie with little or no effective of attack to the current in order to disable the turbine.

Referring now to Figure 4 illustrates schematically a turbine support column which has been adapted or modified to provide support for a water driven turbine unit 21 and an air driven turbine 50. As will be noted the overall height of the column 1 has been increased by effectively providing an extension 51 at the upper part of the support column 1. This extension column 51 serves as the support for the air driven turbine 50.

In practice, the load handling crane 14 would be suitably positionally set to accommodate the extension. Alternatively other load handling arrangements can be utilise.

As is shown in the Figure 4 the housing 8 takes a different form and position on the column to allow for the extension column 51, The housing 8 as with the previously discussed housing construction incorporates arrangements for controlling the positioning of a sleeve 53 that carries the water current turbine. In the Figure 4 the construction of the sleeve 53 is such that it carries the turbme unit 21 from an associated support frame 22. In addition, the length of the sleeve is such that the housing 8 is always above the water level 4 what ever the state of a tide and river level. With this arrangement in order to avoid the need to provided for rotation of the sleeve the rotor 26 of the turbine unit 21 would incorporate the facility of pitch control such as that discussed above in relation to Figures 2 and 3. if desired depending upon the number of blades on the rotors the three blade pitch control disclosed in our copending Application Water Current Turbine with Pitch Control can be adopted. In addition the turbine could be mounted to an vertically displaceable outer sleeve such as disclosed in Figure 1.

As will be apparent from Figure 2 relationship between the column 1 and the extension 8 thereof is such that the sleeve on the column can be raised sufficiently to position the water driven turbine above the water level, for example, the purposes of maintenance and or replacement.

The arrangement of the water current turbine and the air current turbine provides a hybrid combination of wind and water powered equipment (not shown) for utilising the energy obtained by the respective turbines. An advantage of installing a wind turbine on the column/pile is that the overheads involved in installing a column/pile and connecting it to an electricity grid on the shore are high, so by adding a wind turbine significantly more energy can be capture from a single/common installation. This requires the use of a stronger cotumn/pHe having thicker watts to handle the increased bending moment caused by the wind turbine However, it is considered that the extra energy gained would outweigh the extra installation costs. In a variation the wind turbine is mounted from a tower provided at the top of the column/pile.

In the Figures 4 an 5 the wind is shown blowing from the same direction as the current. However, the wind turbine would be of the kind, which can orient its rotor automatically to face in the direction from which the wind blows so that the wind turbine rotor may face in any direction. That is to say the support arrangements for the air driven turbine would be such as to enable such rotation The water current turbine will either be of the kind mounted upon a sleeve which can be yawed through 180 degrees to face the current from either direction or it can have a variable pitch rotor in which the rotor blades can be pitched through as much as 180 degrees to take energy efficiently from flow in either direction. In the Figure 4 both turbines are shown in their operational positions.

Tt bill be understood that if desired the installation could incorporate two water current flow turbines carried from the associated common support column. Also it is possible to provide multiple turbine installations in which a turbine carrying cross bar for water current flow turbines is provided between two spaced columns Similarly air a corresponding number of air flow turbines could be provided upon a cross bar arranged above water level.

Claims

CLAIMS 1. A turbine installation including a water current flow turbine and an air drivable turbine, the arrangement being such that each form of turbine contributes to the production of energy.
2. A turhine installation as claimed in claim 1, and including a column/piie upstanding from a river or the sea bed to project above the water level, for supporting the water current turbine on that section ot the column hclow xvater level and a wind responsive turbine on a section of the column that is always above water level.
3. A turbine installation as claimed in claim I or 2, wherein in order to accommodate change of the direction of water and/or air flows with respect to the respective turbines arrangements are provided for controllmg the pitch of the turbine rotor blades in response to change in direction of water and/or air flow through the turbine rotors
4. A turbine as claimed in claim 3, wherein the operational pitches of the blades of the rotor are of both types of turbine selectively separately adjustable.
5. A turbine installation as claimed in claim 2 or 3, and wherein the operational setting of the pitches of the turbine blades of the associated turbine are selectively settable throughout a range of ! 80 degrees of rotation.
6. A turbine installation as claim in claim 3,4 or 5, wherein the water current flow turbine is so mounted to the column to be bodily displaceable length ways of the column/pile so that the turbine is positionable at or above water level.
7. A turbine installation as claimed in any preceding claim 2 to 7, and includmg load handling means for bodily displacing the water current flow turbine tollonving its separation from its operational connection with the column/pile.
8. A turbine installation as claimed in any preceding claim and including more than one water flow turbine.
9. A turbine installation as claimed in claim 8, and including more than one air flow turbine.
10. A turbine mstallation including a water current flow turbine and an air drivable turbine the arrangement being such that each form of turbine contributes to the production of energy arranged to operate substantially as herem before described with reference to the accompanying drawings.