GB2312931A

GB2312931A - Fluid powered rotary generator

Info

Publication number: GB2312931A
Application number: GB9708446A
Authority: GB
Inventors: Leonard John Dawkin
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-05-11
Filing date: 1997-04-28
Publication date: 1997-11-12
Anticipated expiration: 2017-04-28
Also published as: GB9708446D0; GB2312931B

Abstract

A generator, suitable for deriving power from waves or tides, has paddles 17 pivotable between open and closed conditions (in which closed condition, each vane abuts the vertical rotor shaft 14) to give unidirectional rotation. The generator may be contained in a tubular housing comprising a U-shaped channel 12 having a lid (13, figure 1) and having pivoting baffles 21 operable to direct fluid towards paddles 17 in the closed condition, irrespective of the direction of flow through the housing. A reduction gear may be provided.

Description

ROTARY DEVICE FOR A WAVE & TIDE GENERATOR This invention concerns a fluid powered rotary device having a single direction of rotation when subjected to fluid flows in opposite directions. The device is especially suitable as part of a wave and/or tide powered electrical generator.

Many different kinds of wave and tide generator have been proposed of which the most famous is probably that on the estuary of the river Rance in France. The Rance generator is a massive fixed structure comprising a dam incorporating turbines which are powered by tidal flows into and out of the estuary. This kind of generator is rather expensive to construct and relies on the very large tidal ranges which are found in the English channel and on the north coast of Brittany in particular.

Another kind of generator relies on the impulse of a wave travelling into a throat, but again this kind of device requires an expensive fixed installation and is only suitable for use in relatively rugged coastal areas where the demand for electricity tends to be low.

Yet another kind of generator relies on the rise and fall of waves, but this device will not work in calm seas and has the additional disadvantage of a low mechanical efficiency in turning reciprocal movement into the rotary movement necessary for an electrical generator.

Finally tidal generators are known, but are generally not suitable for flows in both directions. Accordingly they may be arranged to work unidirectionally, or include a sprag or one-way clutch to prevent reverse rotation.

What is required is a relatively simple and inexpensive generator that is suitable for use in all sea conditions, is relatively unobtrusive, quiet and efficient, and which will work with tides or waves or both.

According to the invention there is provided a generator defining a flow path and having a rotor rotatable about a rotor axis in the flow path and a plurality of paddles, wherein each paddle is freely pivotable on a pivot axis substantially adjacent an edge of the paddle and parallel to and spaced from the rotor axis, and wherein each paddle has associated therewith a stop arranged for abutment with the respective paddle to hold the paddle in a closed condition wherein the respective paddle is located between the respective pivot axis and the rotor axis and substantially radially of the rotor, the stops being arranged to prevent pivoting of the paddles through the closed condition, the paddles each being pivotable away from the closed condition in the same rotational sense.

In that way, fluid flowing through the flow path will cause the paddles of substantially half of the rotor to be urged into the closed condition, and the paddles of the other half to be urged out of the closed condition into the direction of fluid flow. The effect of flowing fluid reacting on the paddles in the closed position will cause the rotor to rotate. The sense of rotation is not dependent on the direction of fluid flow through the flow channel.

Clearly, the sense of rotation of the rotor is governed by the sense of rotation in which paddles may be pivoted away from the closed condition, and the sense of rotation of the paddles may be selected for a given direction of rotor rotation. The rotation of the rotor will cause paddles oriented in the direction of fluid flow to return to the closed condition. The device will operate with the orientation of the axle horizontal or vertical.

The flow path may be defined by a tubular housing.

The housing may be of a substantially rectangular crosssection.

Preferably the rotor comprises two parallel plates spaced apart on a rotor axle. The rotor axle may be journalled in the housing and may extend through the housing. The rotor axle may be used as a drive shaft for the supply of rotational kinetic energy to an as mature of a mechanical to electrical generator.

In the preferred embodiment, each paddle is pivotable on a respective spindle parallel to and spaced radially from the rotor axle. Each spindle is preferably journalled between the parallel plates. The spindles may be spaced equiangularly about the rotor axle on the same pitch circle diameter.

In the preferred embodiment, the rotor comprises two parallel end plates and a middle plate parallel with and located centrally between the end plates. Each spindle may be journalled between the middle plate and one or other end plate. The spindles may be equiangularly spaced on either side of the middle plate. The spindles may be offset so as to alternate evenly around the pitch circle.

Preferably, each paddle is longer than the radial distance between the respective spindle and the rotor axle.

Accordingly, the stop may be defined by the rotor axle. The rotor axle can be connected directly or through a step-up gearbox to a standard kind of electrical generator.

In a preferred embodiment the generator includes two baffles; each baffle may be arranged pivotally on the housing. Each baffle is preferably arranged to move between active and passive conditions; preferably fluid flow along the flow path is operative to urge each baffle into one or other of those conditions. In the active condition, the respective baffle is arranged to direct fluid towards paddles in the closed condition. Each baffle may be substantially laminar.

Other features of the invention will be apparent from the following description of a preferred embodiment shown by way of example only in the accompanying drawings in which: Fig. 1 is an end view of a rotary device in accordance with a first embodiment of the invention; and Fig. 2 is a plan of the embodiment of Fig. 1 but with the top cover removed.

With reference to the drawings a fluid powered motor comprises a rectangular tubular housing 11 consisting of a 'U' shaped channel 12 and a removable lid 13.

Aligned circular apertures in the top and bottom of the housing 11 define bearings of a rotatable shaft 14 which in use is orientated vertically. Attached to the shaft 14 just inboard of the walls of the housing and at the middle are circular plates 15A-15C between which are journalled spindles 16A-16L on the same pitch circle diameter. The spindles 16 are equiangularly spaced on either side of the middle plate 15B but offset so as to alternate evenly around the circumference.

A respective paddle 17A-17L is pivotally mounted on each spindle. Each paddle 17 is rectangular and is mounted by one edge, and extends sufficiently inwardly to abut against the shaft 14. The shaft thereby acts as a stop to prevent arcuate movement of the paddles through the radial condition.

Aligned circular apertures in the top and bottom of the housing 11 also define baffle bearings of baffle shafts 20A,20B. The baffle shafts 20A,20B are orientated parallel to the shaft 14. The baffle shafts 20A,20B are adjacent opposite walls of the channel 12 and diametrically opposite each other with respect to the shaft 14.

Pivoted on each baffle shaft 20A,20B is a baffle 21A,21B. Each baffle 21A,21B is substantially rectangular and laminar; a circular bore 22A,22B extends along one edge of the baffle 21A,21B and the baffle shaft 20A,20B extends through the bore 22A,22B. The baffles 21A,21B are freely pivotable between a passive condition where they are oriented parallel with and adjacent the channel wall and directed away from the shaft 14, and an active condition where they are directed into the channel and towards the shaft 14. Baffle 21A is illustrated in Fig. 2 in the active condition; baffle 21B is illustrated in the closed condition. Pivoting between the passive condition and the active condition constitutes movement through an angle of about 1350. A stop 23A,23B is provided on the baffle 21A,21B which abuts against the channel wall in the active condition to prevent movement beyond that position.

In use, flow of water through the housing 11 in the direction of arrows A in Fig. 2 causes baffle 21A upstream of the shaft 14 to be urged into the active condition. The baffle 21A directs the water over the upper paddles (17B, 17G, 17A, 17L, 17F) on the side of the channel opposite the baffle 21A. The flow of water urges the paddles into abutment against the shaft, thereby causing torque to be imparted to the shaft 14, and causing the shaft to rotate.

The paddles on the other side of the channel are urged out of abutment with the shaft by flow of water through the channel. Accordingly, little or no torque is imparted to the shaft 14 in the opposite direction.

It can be seen from the drawings that reversal of flow through the housing 11 causes baffle 20B to move into the active condition, the baffle 20A to move into the passive condition, and the arrangement of the paddles to reverse.

Torque is therefore imparted to the shaft in the same sense by the action of water on paddles 17E, 17J, 17D, 17I, 17C and it will be apparent that rotation of the shaft is always in the same sense.

In an alternative embodiment, the rotor has five equi-spaced paddles to avoid the kind of difficulties sometimes associated with symmetrical designs. More or less paddles can be provided according to the relative dimensions of the rotor design.

In another embodiment the rotor assembly is journalled on the rotor axle for free relative rotation. An output gear of the rotor is connected to a layshaft gear of a parallel axle, and a second layshaft gear is connected to a gear on the rotor axle itself. In this way a simple and compact gear reduction can be effected. Other kinds of compact reduction gear are possible, for example an epicyclic gear unit, according to circumstances of use.

Claims

CLAIMS:

1. A generator defining a flow path and having a rotor rotatable about a rotor axis in the flow path and a plurality of paddles, wherein each paddle is freely pivotable on a pivot axis substantially adjacent an edge of the respective paddle and parallel to and spaced from the rotor axis, and wherein each paddle has associated therewith a stop arranged for abutment with the respective paddle to hold the paddle in a closed condition wherein the respective paddle is located between the respective paddle pivot axis and the rotor axis and substantially radially of the rotor, the stops being arranged to prevent pivoting of the paddles through the closed condition, and the paddles each being pivotable away from the closed condition in the same rotational sense.

2. A generator according to claim 1 and further including a tubular housing for the rotor.

3. A generator according to claim 2 wherein the rotor comprises two parallel end plates spaced apart on a rotor axle, the rotor axle being journalled in said housing and extending through the housing, and the axle being connected for rotation with said rotor.

4. A generator according to claim 3 wherein each paddle is pivotable on a common pitch circle diameter and journalled between said parallel end plates.

5. A generator according to claim 4 wherein the spindles are spaced equiangularly about the rotor axle.

6. A generator according to claim 3 wherein the rotor further comprises a middle plate parallel with and located centrally between said end plates.

7. A generator according to claim 6 wherein each paddle is pivotable on a common pitch circle diameter, each spindle being journalled between said middle plate and one or other of said end plates.

8. A generator according to claim 7 wherein said spindles are equiangularly spaced on either side of said middle plate.

9. A generator according to claim 8 wherein said spindles are offset so as to alternate evenly around the rotor.

10. A generator according to any preceding claim wherein each paddle is longer than the radial distance between the respective spindle and the rotor axle, the stop being defined by the rotor axle.

11. A generator according to any preceding claim and further including two baffles, each baffle being arranged pivotally on a housing, and arranged to move between active and passive conditions, in use fluid flow along the flow path being operative to urge each baffle into one or other of said conditions, such that in the active condition, the respective baffle is arranged to direct fluid towards paddles in said closed condition.

12. A generator according to any preceding claim wherein said rotor is fixed for rotation with said rotor axle.

13. A generator substantially as described herein with reference to the accompanying drawings.