GB2340892A

GB2340892A - Water driven pump

Info

Publication number: GB2340892A
Application number: GB9818159A
Authority: GB
Inventors: Norman Frank Surplus
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-08-21
Filing date: 1998-08-21
Publication date: 2000-03-01
Also published as: GB9818159D0

Abstract

A water driven pump, suitable for use in seas or rivers, comprises water driven blades 1, attached to a hub 2, which is connected to a water pump 3, which is connected to hoses extending alongside a securing strop 6. Water enters the pump 3 through a funnel-like inlet 4, via a guard mesh 5. A buoyancy chamber 7, is provided, and the device may be anchored, along with other similar devices, to an inclined mooring line (fig. 2). Reference is also made to using buoyancy, and the hydrodynamic shape of the housing surrounding the pump and buoyancy chamber, to control the attitude of the device, and to mooring the device to a line on the surface or to a submerged or floating structure.

Description

2340892 OPEN WATER IMPELLER DEVICE This invention relates to a water

driven impeller device.

Water driven impellers are well-known devices that convert kinetic energy from moving water into more useful forms of energy, primarily rotational energy. The resultant rotational energy produced can be subsequently used in a number of ways. They are found both in closed pipes (e.g. as a turbine for generating hydro electricity) and in open free flowing water.

Open free flowing water impellers are usually limited in size, commonly used to measure tile rate of flow of a given body of water, or as a ship's log to measure the speed of the vessel through the water. The rotational energy is usually converted to a small electrical signal being relayed to a gauge. To date, some attempts have been made in using a larger scale impeller to generate electricity in an open water environment, however these efforts have concentrated on generating electrical power directly from the rotational energy produced.

According to the present invention there is provided an open water impeller comprising of a multi-bladed rotating hub which is attached to a water pump drive shaft. A streamlined housing is provided around the pump and hub, the pump end of which is fixed from rotation, the hub end being able to rotate freely. The housing is shaped to act as a hydrofoil to assist in overcoming the inherent buoyancy of the device when water flow past the device reaches a certain velocity. The fixed end has a shaped opening to encourage water flow into the purnp inlet, there is a guard over this open end to prevent debris entering the pump mechanism and a fixing point is provided to tether the device to its mooring cable or fixed structure. The rotating end houses the hub, blade attachments and the main buoyancy chamber for the device. A high-pressure hose connects the output of the pump to the remote receiving station. The device is typically moored underwater in such a way as to allow the device to swivel over or under its fixing point in order to always lie in a downstream position.

Referring to the drawing the open water impeller comprises essentially of one fixed and one moving part, the device as a whole being allowed to subsequentily pitch on its moorings.

In Fig 1, the cut away section (side profile) shows the blades I attached to the rotor hub 2, which in turn is attached to the water pump 3. Water enters the pump through the open end of the device 4, having been screened from any debris by the guard mesh 5 and is pumped into the high- pressure system via hoses alongside the securing strop 6. This strop allows tile device to swivel towards the surface (or seabed) and can be swivelled 180 degrees to allow the device to face the opposite direction. The main buoyancy chamber 7 (if given positive buoyancy) allows the free end of the device to rotate upwards when the flow rate has dropped below a minimum limit (for example at the turn of the tide) and allow the rotor to be lifted above any of the mooring infrastructure. On the return of the reversed flow, the drag of blades and the shape of the streamlined body forces the device to adopt its new working attitude pointing the other way with the device lying flipped over. This enables the high- pressure system of hoses to be attached to the moorings on their way to the receiving station without the risk of being tangled, as the device only ever rotates through a vertical arc of 180 degrees.

In certain situations it may be desirable to allow the free end of the device to rotate underneath itself. In this situation the device is given negative buoyancy to enable it to sink under the mooring infrastructure during slack water.

I An example deployment of the system is shown in Fig 2. This system can be deployed wherever a none vertical mooring line can be secured, typically between fixed points oil tile sea/river bed and the shoreline or from one, two or more seabed anchor points to floating structures. In the example, the mooring cable is fixed to the seabed at anchor point 8 and the impeller units 9 are attached whilst floating on the surface. The distance 10 between tile anchor point 8 and the first impeller is therefore at least equal to the depth of the water above the anchor 11, to enable surface maintenance of the units. By tensioning tile mooring cable at anchor point 12 the buoyancy of the units is overcome and they become totally submerged.

Navigation buoy 13 can be added if appropriate to the situation.

The high-pressure water system is fed through a network of hoses along the mooring infrastructure to the receiving station 14, which is ideally situated close to sea level to avoid an excessive head of water (unless a gravity, pump storage system is being incorporated). The high-pressure water system is used to run a conventional water turbine to enable generation of electricity. The spent water from the hydraulic system is returned to the sea/river.

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Claims

I - A submerged open water impeller comprising a multi-bladed rotor, connected to a pump (and associated hydraulic system) which is fixed from rotation to a mooring, enclosed in an actively streamlined housing, that incorporates a buoyancy chamber (either positive or negative) and a funnelled water intake opening which is protected by a guard mesh.
2. An open water impeller as claimed in Claim I wherein inherent buoyancy (either positive or negative) is used to change the attitude of the device, to enable use in opposite directions.
3. An open water impeller as claimed in Claim I or Claim 2 wherein body shape of the housing is used as a hydrofoil to change the attitude of the device to overcome inherent buoyancy (either positive or negative), to enable use in opposite directions.
4. An open water impeller as claimed in any preceding claim wherein water can be introduced and pressurised via a pump in order to enable useful energy transfer from moving water,
5. An open water impeller as claimed in Claim 4 wherein a guard mesh protects the open end of the pump from water borne debris.
6. An open water impeller as claimed in any preceding claim wherein a liquid or gas can be pressurised via a pump in a closed pressurised system in order to enable useful energy transfer from moving water.
7. An open water impeller as claimed in any preceding claim wherein the device is secured under water to a flexible mooring assembly where the device is free to swivel vertically over or under itself.
8. An open water impeller as claimed in any preceding claim wherein the device is connected onto a mooring line on the surface and subsequently pulled under the water using tension on the said mooring line,
9. An open water impeller as claimed in any preceding claim wherein the device is connected onto a secured, submerged or floating structure where the device is free to swivel vertically over or under itself
10. An open water impeller as claimed in any preceding claim wherein the device can be brought to and kept on the, surface using inherent buoyancy to allow for installation, maintenance or replacement.

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