GB2102502A - Extracting energy from a body of flowing water - Google Patents

Abstract

A floating structure comprises an inlet passage of reducing cross-section in the direction of flow communicating at its downstream end with a pair of channels (5a, 5b), Figure I (not shown), alternately opened and closed to the flow from the inlet passage via a pair of moving guides (3a, 3b) located at the sides of the passage. Each channel has a pair of rotary paddles 9a, 10a, Figure III, so arranged that they are in the positions shown when the inlet flow is communicated to the associated channel, whereby the water flows past the paddle 9a, impinges on the paddle 10a and thus moves up into chamber 11a to compress air therein and force it through a valve 12a into a reservoir. The paddles continue to rotate and the guides move so that the inlet flow is directed into the other channel to similarly compress air therein. <IMAGE>

Description

SPECIFICATION Hydraulic air compressor The device consists of a craft, made of wood, metal, or other material, moored in a flow of water, such as river, tide, or surf, containing a hydraulic compressor.

The craft has a large rectangular opening to the flow, at the beginning of a large internal channel, which gradually reduces diemensions to lead into a narrow channel at the donwstream end, which contains the compressor.

This takes the form of twin, side by side, narrow channels, preferably of rectangular section, which fit into the the small channel. These have, at each end, paddles revolving round shafts placed at right angles to the line of the twin channels, and, on the roofs, orifices leading to air containers.

The large channel contains a flow guide, which is a structure comprising a floor and two sides, moving from side to side on a pin flucrum, connecting the floor of the guide to the floor of the craft. The guide is, at the upstream end, as wide as the large channel opening, but at the other end, only as wide as the width of a twin channel. Its function is to direct the flow towards such twin channel as is open and so speed internal flow.

Apart from a small portion at the upstream end of the large channel, where the roof slopes downward, and that part which is semi-circular to include the sweep of the large paddles, the roofs are level with the surface of the outside flow.

The spaces on either side between the large and small channels and the sides of the craft are used as buoyancy chambers, containing ballast together with the bearings of the shafts and the sprocket wheels and chains, referred to later.

To avoid the ingress of flotsam and jetsam it is necessary to cover the entrance to the large channel with a wire mesh screen. When used in surf, the large channel will contain a set of blow off valves, which will operate in series in the event of unusually high pressure caused by storm.

The shaft at the upstream end of the twin channels, mounted on bearings at each side of the small channel, at the same height as the roof, has, mounted upon it, two paddles, one in each twin channel at right angles to one another, each of which sweeps the whole area of the cross section of each channel. A semi-circular extension to the roof, covers the sweep of these paddles. At the downstream end of the twin channels on another shaft, mounted midway between the roof and floor, are paddles which, though only half the length of the other paddles, similarly sweep the whole area of the cross section of the twin channels.These two paddles are, again, at right angles to one another, but in relation to the large paddles, are at an angle of 70 , that is to say, when the large paddle reaches horizontal point, the small paddle in the same twin channel is 20 short of vertical. These figures are given for illustration only as the actual angle will depend on the length of the twin channel and the normal flow velocity.

In the roof of each twin channel, just above the shaft, is an orifice, leading to an air container, which has, at the other extreme from this orifice, inlet and exit non-return valves. The two, shafts are connected by chains, running on sprocket wheels, placed beside the bearings on the outward sides of the twin channels, so that they, revolve in unison.

Sketches are appended which indicate the shape of the structures described herein.

I Plan view of craft.

II Side view of craft.

III Side view of one twin channel (shewing internal working) IV Side view of other twin channel (external).

Parts of the device are numbered in these sketches as follows: la/b Outsides of craft. 2a/b Sides of large channel.

3a/b Sides of flow guide. 4a/b Buoyancy chambers.

5a/b Twin channels. 6 Guide flucrum.

7 First shaft. 8 Second shaft.

9a/b Long paddles. 10a/b Short paddles.

ha/b Air chambers.

12a/b Exit valves. 13a/b Inlet valves.

14a/b Driving wheels. 15a/b Driven wheels.

16a/b Chains.

Operation We commence when water from the external flow enters the large channel, where it proceeds at increasing velocity towards one of the twin channels, which is open, directed by the flow guide. If this is 5a, it passes 9a and reaches 1 Oa, when this is closed. The consequent increase of pressure forces water through the orifice above, into the air chamber 1 la, compressing the air there and when this reaches a predetermined pressure, it escapes through the valve 1 2a, to the air reservoir (not shewn). As the paddles continue to rotate, the pressure drops and the water returns to the twin channel helped by the ingress of air through the valve 13a. As the paddles continue revolving, paddle 9a passes the horizontal position and 9b opens, assisted by the flow guide, which is now moving towards it. Thus, the same compression occurs in 5b and the cycle returns to 5a. In this way, the reservoir is filled with air at at predetermined pressure, which can be used then or later to do useful work.

Claims (6)

1. An air compressor, as described herein, which may be moored in a water flow, such as in river, tide or surf, thus avoiding most of the cost of civil engineering necessary to many other devices which convert water flow energy.

2. An air compressor, as described herein, which automatically faces the line of flow, so that, in a tidal flow, it may be used, without adjustment for incoming and outgoing tide.

3. An air compressor, as described herein, which, by its internal shape, increases the internal velocity of flow above the velocity of external flow.

4. An air compressor, as described herein, which contains a flow guide to reduce the resistance to internal flow, thus further increasing internal flow velocity.

5. An air compressor, as described herein, which uses the counter action of two sets of paddles to increase water pressure, to compress air.

6. An air compressor, as described herein, in which the driving paddles are largerthan the driven, or pressure paddles, thus increasing the air compression.