GB2302709A - Combined tidal power turbine and pumped storage system - Google Patents

Abstract

A lagoon is created by a continuous barrier of caissons 30 located below low tide level to ensure that inlet ports 30A are always under water. The outlet ports are located adjacent to the sea bed, to ensure a scouring action which keeps them clear. Water flows through the inlet ports and over guide vanes 28 to drive blades 12 on shaft 22. The blades rotate, driving generator 14 which is dry housed above the highest water level. Blades 12 also contain hollows 16. Water passes out through these hollows during blade rotation, into spiral duct 18 (plan view in fig. 1), then through outlet port 26 into conduit 34. This climbs above high water level to deposit water into storage tank 32. When tidal activity is low, water may be drained from the tank through outlet 37 and pipe 36 to drive land-based generator 39. Alternatively, water may be drained out to the caissons to drive blades 12. Distribution of stored water may be controlled manually, or by tidal activity sensors or time clocks (not shown). The apparatus may be used in canal locks, or in rivers.

Description

COIBIJED POWER GERERATlIG AID PUKPIJG APPARATUS The present invention relates to combined power generating and pumping apparatus, and particularly but not exclusively to apparatus for generating electrical power from tidal motion.

Conventional arrangements used to generate electrical power from tidal motion are susceptible to fluctuations in power generation because power generation is directly dependent upon and thus determined by the natural fluctuations of tidal motion.

Therefore conventional apparatus is limited as to its ability to generate power according to demand.

It is an object of the present invention to provide improved power generating apparatus and to obviate or mitigate the above disadvantage of the prior art.

According to the present invention there is provided combined power generating and pumping apparatus comprising a rotary blade arranged to rotate under the influence of fluid flowing through the apparatus, and means to generate electrical power from rotational movement of the blade, the blade defining a passage to receive flowing fluid, and which extends generally outwardly from the axis of rotation of the blade towards a collecting conduit to channel and thereby pump fluid into the collecting conduit.

Preferably the passage extends along the blade to be generally perpendicular to the axis of the rotation of a hub from which the blade extends. Preferably a plurality of blades, each of which preferably comprises a passage as aforesaid, extend radially and desirably equidistantly from the hub to be communicable with a collecting conduit.

Preferably the hub is hollow to receive flowing fluid and is in fluid communication with the said blade < s). The hub may be rotatably mounted within a housing. The housing preferably defines a through passage across which the blades) are located to be acted upon by fluid flowing through the passage.

Preferably one or more guide formations are provided to guide fluid onto the blades). The or each guide formation may be provided generally at the entrance to the through passage of the housing. One or more guide formations may also be provided generally at the other end of the through passage. Preferably the apparatus is arranged to be operable to receive fluid through either end of the passage and generate and pump as aforesaid.

Preferably a single collecting conduit is arranged to receive fluid from the blades) and is preferably so shaped to cause substantially unidirectional movement of fluid channelled thereto, therealong toward an outlet. Alternatively or additionally two collecting conduits are provided, each to receive pumped fluid which entered the passage through a rapact= e.d thereon. he or eacn collecting conauit is preferably generally volute-shaped and may increase in crosssectional area in the direction toward the outlet to assist the pumping action of the apparatus. The or each collecting conduit may be connectable to further means, such as a conduit to carry pumped fluid away from the apparatus.

Preferably the generating means is located above the High Water line of the water flow. Preferably the apparatus is locatable within a liquid such as water, in a support such as a caisson having inlet and outlet ports located within the caisson wall so that there are two upper inlet ports and two lower outlet ports arranged in a line vertically as in 30A.

The apparatus will be located between the upper and lower pairs of ports so as to receive the flow of water passing from the upper to the lower ports, desirably to be selectively removed therefrom and arranged to be operable to generate electrical power and pump water siniultaneously as tide water flows therethrough.

The caisson will have half cones or quatro-spherical segments rotatable through 1800 at each port level arranged in opposition as in 3 to direct tide water downwards through the apparatus during both rising and receding tide water levels. A plurality of apparatus may be so arranged, desirably in series to form at least part of a barrier, which desirably defines a lagoon in the liquid.

Preferably the apparatus comprises part of a tidal power generating assembly operable to use tidal motion to generate electrical power and substantially simultaneously pump sea water.

Preferably the apparatus is positioned on the seaward side of the low tide level such that the blades are continuously submerged in sea water, and orientated to receive tidal water in the entrance.

Preferably the outlet of the collecting conduit is connectable to storage means for the storage of liquid pumped from the apparatus. Preferably the storage means is located at an elevated position relative to the apparatus, and is desirably located on the shore. Preferably the storage means is selectively openable to channelling means to enable selective channelling of fluid from the storage means back to further electrical power generating means and/or to the apparatus to cause rotational movement of the blade(s) and thus operation of the apparatus.

Preferably the storage means is selectively operable to channel liquid as aforesaid during or substantially at periods of relatively low tidal motion so that the electrical power is continuously generated. Preferably the storage means is automatically opened by actuating means at predetermined times or as a result of sensing means sensing relatively low tidal motion.

The apparatus may be locatable in a canal or similar waterway in which lock arrangements are operable. The apparatus may be located in sluiced gates and desirably operable to return water from the lock to the waterway thereabove.

According to a further aspect of the present invention there is provided a generating assembly for generating electrical power from tidal motion, the assembly comprising apparatus as defined in any of the preceding paragraphs and storage means connected thereto substantially as defined in any of said paragraphs.

Further according to the present invention there is provided a method of generating electrical power, the method comprising locating, at a point of at least intermittent fluid flow, generating means operable to generate electrical power from flowing fluid and also to pump fluid, during fluid flow generating electrical power therefrom and simultaneously pumping fluid to storage means, and selectively channelling the fluid from the storage means to generate electricity during periods of relatively low fluid flow.

The fluid may be selectively channelled from the storage means to conventional electrical power generating apparatus and/or back to the generating means of the present invention.

Preferably the method uses tidal motion to provide the flowing fluid and uses both in-flowing and out-flowing tidal motion.

The generating means preferably comprises apparatus according to any of said preceding paragraphs.

Preferred embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional view of apparatus according to the present invention.

Figure 2 is a cross-sectional view along the lines II-II of figure 1; and Figure 3 is a schematic representation of the apparatus of figure 1 in use in a power generating assembly, in accordance with the present invention.

Referring to the drawings, there is provided combined power generating and pumping apparatus 10 comprising a rotary blade 12 arranged to rotate under the influence of fluid flowing through the apparatus 10, and means 14 to generate electrical power from rotational movement of the blade 12, the blade 12 defining a passage 16 to receive flowing fluid and which extends generally @@@wally @@@@@ the axis A of roation of blade la toward a collecting conduit 18 to channel and thereby pump fluid into the collecting conduit 18.

In more detail, equidistantly spaced blades 12 radiate from a central, hollow hub 20. The inside of the hub 20 is in communication with the passage 16 in each of the blades 12. Each passage 16 is also in communication at its other end with the inside of the collecting conduit 18. The hub 20 is mounted on a shaft 22 with a bearing (not shown) to permit rotation of the hub 20 and blades 12 within a housing 24. The housing 24 defines a passage 25 through which fluid can flow to impinge upon the blades 12, mounted generally centrally in the passage for operation thereof. The passages 16 open into the collecting conduit 18.

The collecting conduit 18 extends around the outside of the housing 24 and defines a volute-shaped interior increasing in cross-sectional area generally in the direction of the rotation of the blades 12, to thereby ensure unidirectional flow of fluid from the blades 12 along the collecting conduit 18, to enhance the pumping effect. The collecting conduit 18 has an outlet 26 at its enlarges open end which is connectable for further means as will be discussed.

Guide vanes 28 are provided at the entrance to the passage 25 of housing 24 to deflect fluid onto the blades 12. Similar vanes 28 may be provided on the other end of passage 25.

In use, with reference to figure 3, the apparatus 10 is mounted in a support, such as a caisson 30 having guide vanes 30A to direct water onto and away from the apparatus 10 which is always submerged in liquid. The principle intended application of the apparatus 10 is in the generation of electrical power using tidal motion, and the following description relates to this application. However, it is to be appreciated that further applications are possible.

The supports 30 are anchored to the sea bed B by any suitable means with the apparatus 10 therein in an orientation to receive incoming tidal motion. A series of supports 30 comprising one or more apparatus 10 are linked in series to form a barrier, for example to define a lagoon in a foreshore region. The apparatus 10 are located on the seaward side of the low tide level to be continuously submerged in sea water, even at low tide.

Each apparatus 10 is connected to a storage reservoir 32 by a conduit 34. The reservoir 32 is sited on the shore to be elevated relative to the respective apparatus 10 desirably about six metres above further generating means 30. The conduit 34 extends form the outlet 26 to an inlet 31 of the reservoir 32, above the maximum water level to prevent any syphoning effect.

A conduit 36 is provided extending between an outlet 37 of the reservoir 32 to open generally at the further, conventional electrical power generating means 39.

A closure device 38 is provided at the outlet 37 to enable selective control of release of water from the reservoir 32, through the conduit 36 to conventional water turbine/generator 39.

During periods of relatively high tidal movement, the sea water flows through the apparatus 10 towards the shore, causing the blades 12 to rotate and the generator 14 to generate electricity.

This electrical power is then tapped as appropriate.

Simultaneously, the water as it passes through the hub 20 is urgea aiong Ine passages io Dy centriIugai force, into tne collecting conduit 18. The movement of the water entering the collecting conduit 18 and the shape of the conduit 18 ensures the unidirectional movement of the water therealong and therefore effectively pumps the water to the outlet 26. The water passes through the outlet 26 along the conduit 34 into the reservoir 32 < the outlet 37 is closed by the closure member 38), where the water is stored.

During periods of low tidal movement, the closure device 38 is opened fully such that stored water can flow down the conduit 36 to act on the conventional generating means 39 to generate electricity. The water is then channelled back to the sea, into the lagoon if the tide is receding or to the sea if the tide is rising. This ensures that electrical power is generated continuously, irrespective of the tidal conditions.

Once tidal motion increases beyond a predetermined value the closure device 38 is moved again to restrict the outlet 37 so that water can again be stored.

The activation of the closure device 38 may be manual, but is preferably automatic as a result of signals from sensors (not shown) operable to sense the level af tidal motion, or signals from a timing device < not shown).

This therefore gives the present invention significant advantage over prior art, the latter belong vulnerable to Iluctations in tidal activity.

In a further embodiment of the invention, the stored water is channelled back to the apparatus 10 during periods of low tidal motion, so that the apparatus 10 generates electricity during these periods. The conduit 36 in this case, would extend between the outlet 38 to a position Just before the entrance to the apparatus 10, such that as water exits the conduit 36 it impinges on the blades 12.

It is to be appreciated that whilst the apparatus has been described principally for use in tidal power harnessing systems, it is equally applicable to other systems, and may for example be installed in sluiced gates for canals for use during the operation of locks.

Various modifications may be made without departing from the spirit or scope of the present invention. For example, any number of blades 12 may be used.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims (6)

1. This is a mechanical device which utilizes the energy available in Tidal flows to simultaneously generate electricity and provide pumped water storage for use in generation during periods of slack water.

2. The arrangement of outlet ports enables scouring of the sea bed below the inlet ports thus avoiding silting up.

3. The runner of the prime mover is easily accessible for maintenance or replacement.

4. Only well established principles of construction and operation are involved.

5. The principles of this device may be used for the recovery of Lock water in a canal or river system for water conservation.

6. Omit.

6. A Prime Xover extracting energy from the free movement of water.

Amendments to the claims have been filed as follows 1. This is a mechanical device operating as a prime mover which directly converts the energy available in flowing water into mechanical energy providing both mechanical torque and pumped water flow at the same instant from a single rotor and which when fitted horizontally within a caisson as described in Drawing 3 will utilize Tidal Water flows for electrical generation.

2. When fitted within a caisson according to Claim 1. the arrangement of outlet ports enables scouring of the sea bed below the inlet ports thus avoiding silting up.

3. According to Claim 1, the rotor of the prime mover is easily accessible for maintenance.

4. According to Claim 1. only well established principles of construction and operation are involved.

5. According to Claim 1, the principles of this device may be used for the recovery of Lock Water in a canal or river system to conserve water.