GB2437297A

GB2437297A - Tidal barrage with unidirectional turbine

Info

Publication number: GB2437297A
Application number: GB0607805A
Authority: GB
Inventors: Keith Dudley John Apps
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-04-20
Filing date: 2006-04-20
Publication date: 2007-10-24
Also published as: GB0607805D0

Abstract

A turbine arrangement for a tidal barrage comprises inlets and outlets E, F on both sides of the barrage. Gates G are switched to ensure that water always flows through the turbine in the same direction. Each inlet and outlet is provided with a vertically sliding sluice valve to allow the passage(s) to be shut off as required. The inlets E, F may be provided with screens to protect against damage from foreign matter.

Description

POWER LIMITED

Application Fluxion System for Ebb and Flow Turbine Ebb & Flow (A&B) The turbine would be positioned with the blade tips facing towards the sea and the estuary, this would then put the drive shaft facing the length of the barrage. Its size or blade diameter would be governed by the Q M P S flow rate, and the number of units' different project could accommodate.

Leat Chamber (C) The facade area of the leat chamber entrance should be at least twenty five percent bigger in area than that of the swept area of the turbine blades.

Tail Race (D) The facade surface area of the tailrace chamber should be at least ten percent bigger than that of the swept area of the turbine blades.

Trash Screens (E) Both ebb and flow screens standing of the original structure would protect flow and ebb entrances.

Leat and Tailrace Shutters (F) External shutters would be installed to the leat and tailrace openings, their operational mode would be in a vertical direction, when opening and closing.

Internal Directional Gates (G) Both gates would operate in a clockwise or anticlockwise direction when standing with your back against the draft tube area. The positioning of the directional gates would be directly opposite the draft tube, in the leat chamber and the tailrace chamber. The gates themselves would be pivot hung in a vertical position, and the top section of the shaft would incorporate the opening mechanism.

Draft Tube (H) The draft tube area extends from the leat chamber to the tailrace chamber Fluxion System A Barrage system is normally constructed from a number of different types of caissons, one of these caissons houses the turbine facility. It is within this caisson that the Fluxion System relates to. This invention imposes a directional change of the natural flow of the Estuary within the confinement of the caisson. The number of units varies from site to site, but is governed by the width of the Estuary, tidal reach and the amount of water retained within the Estuary.

The current thinking is to install the draft tube in parallel with the flow of the Estuary, but separate turbines are required to capture the power from the incoming tide and the out going tide. This system encapsulates both sequences thus reducing the number of turbines required by 50%. When introducing an object into the flow of water directly behind that object turbulence starts to form, this is why the blades must always be the first point of contact to the flow of water. (A&B)

When looking on plan the angle of the leat chamber compared to that of the draft tube must not exceed more than 60 degrees. The preferred angle of entry into the draft tube is normally 45 degrees. The external entrance of the leat chamber is showing a splay of degrees to that of the caisson facade, when viewed on plan. This was brought about by the length of the chamber walls in retrospect to the distance travelled by the water over their surfaces from each other, this in turn necessitated an equal length on both sides of the leat chamber. (C&D)

Because of the nature of any fluid, when flowing over a surface, any undulations introduced to that surface start to induce variations into the equation, the greater the speed of water the bigger the problem, this shows up by exaggerating the physical profile of the feature beyond its natural form. To over come this problem, when a directional change is introduced, it was found that by enlarging the vertical surface area of both chambers compared to that of the draft tube entrance the problem was then mitigated to a certain extent. Increase in area required was 25% for leat chamber and 10% for that of the tailrace chamber. (E)

The trash screens would be required to both leat chamber entrances they would be secured back to the original structure but stand proud thus enabling the installation of the shutters. The reason for these screens is to safeguard the turbine blades from foreign matter within the water. (F)

The two leat and tailrace shutters are a requirement, which enables the retention of both flow and ebb tides at any given time. The operational mode is such that when the leat entrance shutter is open to the sea the tailrace shutter facing the sea is locked out for operation, this then opens the tailrace shutter facing towards the estuaiy. This mode of operation is then reversed to capture the energy from the outgoing tide. (G

The internal directional gates are positioned such so as to deflect the flow of water into and out of the draft tube area which contains the turbine, they also close of part of the chamber from unnecessary use. The opening and closing of these gates must only take place when all external shutters are in their closed position, this is to help reduce unnecessary external pressures on the mechanical equipment for opening and closing of the gates. (H)

Draft tube and turbine location contained within, the actual positioning of the turbine will be governed by the amount of turbulence being created by the leat chamber, this will very from site to site in accordance of the volume of water and the speed of water passing through the system. Some sites would enable a greater distance to be achieved from the leat area to the entrance of the draft tube.

Claims

Claims (1) The Fluxion System 1/1 comprises of the flow and ebb

chamber, which then connects to the entrance of the draft tube, this then discharges into the tail race chambers, at the entrance and discharge area of the draft tube is located the two directional flow gates, the four external shutters are located at the entrance and discharge facade to the whole system.

(2) In the Fluxion System according to claim 1/I the leat chamber's have a volume capacity considerably grater than that of the draft tube area, the leat chambers are positioned directly opposite each but at an angle to that of the draft tube, this is to utilise the flow and ebb of the tides.

(3) The Fluxion System according to claim 1/1 discharges the flow of water from the draft tube into the tail race chambers, these are positioned at an angle to that of the draft tube they also have an area grater to that of the draft tube.

(4) The Fluxion System 1/1 contains the two directional flow gates position before and after the draft tube, their function is to direct the flow of water into the draft tube from the leat chamber in to the draft tube, once leaving the draft tube the second directional gate deflects the flow of water into the tail race chamber.

(5) The other function of the directional flow gates is to seal off the two chambers that are not in use, for the system to operate the leat chamber would be opened to allow the sea entry but the tail race chamber would be closed facing seaward, to release the flow of water from the estuary the opposite (6) The Fluxion System 1/1 consists of four external shutters, one at the entrance of each of the leat chambers, and one at the exit of the two tail race chambers their function is to create an imbalance in water levels from one external facade to the other.

(7) The operational mode of the shutter gates is such that they open in tandem to each other, this means that only one gate is open at any one time on each facade, all of the shutters work in a vertical direction to open and close.

(8) The Fluxion System 1/1 contains two external trash screens covering the leat entrances standing proud of the shutter gates, their function is to protect the turbine blades within the draft tube from foreign matter entering the system.