GB2327465A - Omnidirectional air turbine with cylindrical shutter plates. - Google Patents

Abstract

The structure comprises upper (12, Fig. 2) and lower (11) chambers separated by partition (8) having an orifice in which a turbine (9) is mounted. Air is guided to and from the chambers by an orthogonal arrangement of walls 4-7 forming ducts 13-16. Part cylindrical shutters 21, 22 and 23, 24 of the lower and upper chambers respectively are independently motorised to slide in grooves to positions according to wind direction to receive air from the ducts and permit airflow into or out of their respective chamber such that air enters the lower chamber, passes through the turbine into the upper chamber. Adjacent ends e.g. 35, 36 of the shutters can abut and seal such that all air entering the structure can pass through the turbine or can be partially or fully opened to provide bypass (Figs 5, 6).

Description

OMNIDIRECTIONAL AIR DRIVEN POWER GENERATING MEANS The present invention relates to inventive modifications and improvements to the generating means disclosed in my Specification No. US 4018051 dated April 19th 1977.

This invention is directed at improving the productivity and longevity of my previously patented wind turbine.

The storm-force winds found in many parts of the world offer enormous power to a wind turbine which is able to survive the inevitable stresses involved. But the turbine must also be able to utilise the moderate winds which predominate between storms.

In an attempt to satisfy these requirements, US 4018051 described an 'Omnidirectional Air Driven Generating System' in which a large stationary structure enclosed a turbine at its centre. The turbine received an augmented flow of air as a result of the large structure, It also benefited from a one-way flow through its duct, made possible regardless of the wind direction by eccentrically pivoted plate valves, biased to open or close in response to the positive or negative pressures being induced around the fixed structure.

Further, the system included relief valves near the turbine. In the event of overpressure, the weighted or sprung valves were unseated to allow a bypass flow from positive to negative, thus protecting the system.

But this system of valves does not offer the long term reliability or protection demanded by operation in those remote or severe environments which offer the productive wind conditions. eg Scotland, Falkland Islands, offshore windfarms etc. Typically, such valves, when not motor driven, quickly stagnate in ice; their flat areas can distort and fail; their single shaft can he deformed causing bearing seizure. Since they are freely pivoted, they can slam or flutter, leading to drastically shortened life.

Further, during normal conditions, their pendulous operation must impose a wasteful constriction to the working flow.

The relief valves are subject to similar problems, but their main objection is that, in order to relieve pressure, they must maintain some pressure differential across the turbine. Ideally, a means should be provided to completely bypass the turbine to permit preventative maintenance on its machinery in a static environment.

The present invention employs valve plates which, in plan view, are partcylindrical.

According to the present invention I provide an omnidirectional air driven power generating structure which, when exposed to wind, causes the formation of higher than ambient atmospheric pressures in a space adjacent to one side of the structure and lower than ambient atmospheric pressures in a space adjacent to another, generally opposed side of the structure, the structure comprising a hollow housing having an internal partition mounted therein so as to divide the interior volume of the housing into two separated cavities, the partition having an orifice therethrough whereby air can move from one cavity to the other, an air driven power converter mounted within and generally filling the orifice in the partition so that air moving through any portion of the orifice drives the converter, duct means for connecting a different one of the two separated cavities to a different one of the spaces adjacent to the sides of the structure so arranged that a pressure differential can be produced between the two cavities thereby producing a flow of air through the orifice to drive the power converter, and means for switching the connections between cavities and spaces adjacent to the sides of the structure in response to a reversal of pressure polarity caused by a shift in wind direction so arranged that the polarity of the pressure differential, when present, across the partition remains constant, wherein: the duct means comprises a plurality of circumferentially-spaced ducts directed substantially radially of the axis of the orifice, and the switching means comprise a plurality of part-cylindrical shutter plates extending across the radially inner ends of the ducts, the shutter plates being circumferentially movable so as to control the degree of connection between the radially inner ends of the respective ducts and a respective one of said cavities.

A wind-driven turbine structure in accordance with the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which: Figure 1 is a diagrammatic plan view of the structure showing possible Winds 'A' & 'B'; the general arrangement of the turret; and the position of the orifice for the turbine (not shown).

Figure2 is a diagrammatic cross-section taken on line B-B of Figure 1 to show the relationship between the turret, the valves, the duct and the two stage counter-rotating turbine and power delivery shafts, with the valves in a condition appropriate to Wind B.

Figure 3 is a diagrammatic horizontal cross-section on the line N-N of Figure 2 and showing a valve in its sealed mode.

Figures 4. 5 and 6 are combined cross-sections illustrating the three basic valve states of: sealed; pressure relief; and full bypass respectively. They depict the position of the lower (inlet P-P) valves to the left of the drawing and the upper (exhaust N-N) valves to the right. The wind flow is now 'Wind A', and from left to right of the page, and up through the turbine duct.

Figure 6 shows that, at full bypass, the turbine is in a static environment.

Reference should be made to the description of Specification US 4108051, and Figures 1 to 4 thereof, for the general arrangement of the cruciform duct system employed, and how this duct system can utilise wind blowing from any direction.

As shown in the present Figures 1 and 2, a structure 1 comprises a roof plate 2, a base plate 3, four fixed vertical duct walls 4, 5, 6, 7 arranged in a cruciform manner and extending vertically between the roof and base plates 2, 3. The structure can be of any desired size, and could be as large as a power station cooling tower, for example.

A horizontal circular partition wall 8 is positioned midway between plates 2 and 3 and is formed with a circular orifice in which is rotatably mounted a multi-stage turbine 9 on vertical output shaft 10.

A cylindrical air inlet cavity 11 is defined beneath the partition wall 8 and turbine 9, and correspondingly shaped outlet cavity 12 is defined above the wall 8 and turbine 9.

Four radially directed ducts 13, 14, 15 and 16, Figure 1, are defined between the radial duct walls 7 and 4, 4 and 5, 5 and 6, 6 and 7 respectively.

The ducts 13, 14, 15, and 16 connect at their outer ends with spaces 13', 141, 151 and 161 respectively adjacent to the open sides of the structure 1.

The duct walls 4 to 7 are of diamond shape in horizontal cross-section to provide strength against possible twisting forces.

A switching means for controlling the wind flow to and from the ducts, and to and from the turbine 9, comprises four part-cylindrical shutter plates 21, 22, 23, 24 which provide various valve functions, the shutter plates extending circumferentially about the axis of the turbine and in sealing contact with the radially inner edges of the duct walls.

The lower shutter plates 21, 22 are positioned beneath the partition wall 8 and are mounted for circumferential movement in guide tracks 25, 26 in the partition wall 8 and base plate 3 respectively, whereas the upper shutter plates 23, 24 are positioned above the partition wall 8 and are mounted for circumferential movement in guide tracks 27, 28 in the partition wall 8 and roof plate 2 respectively.

The lower plates 21 and 22 act as inlet valves controlling the flow of air to the underside of the turbine, whereas the upper plates 23, 24 act as outlet valves.

As discussed in US Specification 4018051 the cruciform shape of the ducts requires a consideration only of the two wind directions A and B shown in Figure 1, since every other possible wind direction is equivalent thereto, or to a combination thereof.

The shutter plates 21 - 24 derive their strength both from their curvature and their triangular radial cross-section, seen in Figure 2. The shutter plates are able to both (a) direct one-way flow through the turbine 9 when required and (b) bypass excess flow away from the turbine 9 in a precisely controlled manner as described below.

An electric, hydraulic, manual or any convenient propulsion device is mounted on each plate to engage with the fixed structure through a rackand-pinion, wire and winch or convenient mechanism to propel its individual plate to its appropriate position as dictated by the wind state.

Each valve 21, 22; 23, 24 is composed of a pair of identical but independently motorised shutter plates which are positioned normally to seal together at one circumferential end as in Figure 3. However, when necessary, the pair of shutter plates can move apart to provide any desired bypass ratio, up to and including full bypass of the turbine as will be described with reference to Figures 4, 5 and 6.

The shutter plates each extend circumferentially for an arc of substantially 135 to facilitate the condition shown for example in Figure 4, left hand portion, where the plates 21, 22 are positioned in sealing abutment at one pair of adjacent ends 31, 32, whilst the opposite ends 33, 34 seal with the radially inner ends of the duct walls 7, 4 respectively. However, a modified construction is envisaged in which the plates 21, 22 extend through arcs of substantially 900, and intermediate angles would be possible.

The valve conditions shown in Figure 4 are appropriate to a wind direction A, that is where the wind direction is directed substantially at one of the ducts, at an angle in Figure 4 bisecting the angle defined by duct walls 4 and 7. It will be seen in Figure 4 that the shutter plates 21, 22 will direct all of the air passing through duct 13 through the turbine 9 by way of the inlet cavity 11, which is bounded by the inner faces of the lower pair of shutter plates 21, 22.

As shown in the right hand portion of Figure 4 the air issuing from the turbine passes by way of outlet cavity 12, which is bounded by the inner faces of the upper pair of shutter plates 23, 24, and is directed by the plates 23, 24 into the duct 15. The upper shutter plates 23, 24 are positioned as shown to abut one another at adjacent ends 35, 36, the separated ends 37, 38 sealingly engaging the radially inner ends of duct walls 5, 6 respectively.

Figure 5 shows how a degree of bypassing of the turbine can be achieved relative to the condition of Figure 4 by positioning the valve plates 21, 22 such that the ends 31, 32 are separated, and also, if desired, by separating the ends 35, 36 as shown in the right hand portion of Figure 5.

When the wind is from direction B then, as shown in Figure 3, the touching ends 35, 36 of the plates 23, 24 also seal with the radially inner end of duct wall 7, and similarly (but not shown) the touching ends 31, 32 of the plates 21, 22 seal with the opposite duct wall 5.

Figure 6 shows how the valve plates 21, 22, 23, 24 can be positioned to provide a full bypass of the turbine. The gap between adjacent ends 31, 32 of lower plates 21, 22 is made substantially equal to the gap between ends 33, 34 to enable air to pass from duct 13 into inlet cavity 11, and then directly from cavity 11 beneath the turbine to duct 15 without passing through the turbine. The upper plates 23, 24 are oriented in a similar symmetrical configuration to enable air to pass from duct 13 to duct 15 by way of outlet cavity 12 above the turbine. The condition of Figure 6 enables the turbine to be protected from high winds.

Since the shutter plates are slow-moving and free of all weight restrictions, they may be sound-proofed and equipped to counter lightening, microwave radio disturbance and ice accretion.

As compared with the structure of US 4 018 051 the need for variable-pitch feathering rotor blades is removed, and the shutter plates may be weatherproofed since they have no weight restriction.

Claims (8)

1. An omnidirectional air driven power generating structure which when exposed to wind, causes the formation of higher than ambient atmospheric pressures in a space adjacent to one side of the structure and lower than ambient atmospheric pressures in a space adjacent to another, generally opposed side of the structure, the structure comprising a hollow housing having an internal partition mounted therein so as to divide the interior volume of the housing into two separated cavities, the partition having an orifice therethrough whereby air can move from one cavity to the other, an air driven power converter mounted within and generally filling the orifice in the partition so that air moving through any portion of the orifice drives the converter, duct means for connecting a different one of the two separated cavities to a different one of the spaces adjacent to the sides of the structure so arranged that a pressure differential can be produced between the two cavities thereby producing a flow of air through the orifice to drive the power converter, and means for switching the connections between cavities and spaces adjacent to the sides of the structure in response to a reversal of pressure polarity caused by a shift in wind direction so arranged that the polarity of the pressure differential, when present, across the partition remains constant, wherein: the duct means comprises a plurality o f c of circumferentially-spaced ducts directed substantially radially of the axis of the orifice, and the switching means comprise a plurality of part-cylindrical shutter plates extending across the radially inner ends of the ducts, the shutter plates being circumferentially movable so as to control the degree of connection between the radially inner ends of the respective ducts and a respective one of said cavities.

2. A structure as claimed in claim 1 in which the shutter plates are movable to positions in which at least some bypassing of the orifice is provided.

3. A structure as claimed in claim 1 or claim 2 in which the ducts are defined by radial walls arranged in a cruciform configuration, the arrangement being such that the shutter plates control connection between appropriate quadrants of the duct means.

4. A structure as claimed in any of the preceding claims in which the plates are supported on a track assembly extending concentrically around the orifice.

5. A structure as claimed in any of the preceding claims in which the power converter is a multi-stage turbine disc assembly mounted on a vertical power delivery shaft assembly.

6. A structure as claimed in claim 2, or any of claims 3 to 5 when appended to claim 2, in which two or more of the individual plates normally co-operate to form a substantially airtight valve, but can be precisely moved apart to permit various degrees of leak increasing to full bypassing of the turbine.

7. A structure as claimed in any of the preceding claims in which the switching means comprises a first set of part-cylindrical shutter plates positioned on a first side of said partition, and a second set of partcylindrical plates positioned on the second side of said partition.

8. A valve system substantially as described with reference to the accompanying drawings.

8. A structure as claimed in any of the preceding claims comprising an electric, hydraulic, manual or any convenient propulsion device mounted on each plate which engages with the fixed structure through a rack-andpinion, wire and winch or convenient mechanism to propel its individual plate to its appropriate position as dictated by the wind state.

9. A structure as claimed in claim 2 or any of claims 3 to 8 each as appended to claim 2 comprising a control structure able to sense the external wind direction; the pressure-differential in the volume on opposite sides of the power converter; or a stop command, in order to signal the means of plate-drive to cause it to propel the plates to the appropriate position to seal or bypass airflow to maintain the maximum turbine rotary output or reduce it to zero.

10. A structure substantially as described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows CLAIMS

1. A valve system to replace that of my existing patent No. US 4018051 dated April 19th 1977 whereby the valves enable full operation of the generating means without retardation during any extreme of wind speed or turbulence.

2. A valve system as claimed in claim 1 which employs part-cylindrical plate valves which move in circular tracks located concentrically around the inlet and exhaust zones of the orifice in which the air driven power converter is mounted.

3. A valve system as claimed in claim 1 whose valve elements are robustly supported during their movement by tracks at both their bottom and top edges, the tracks being embedded in the main structure.

4. A valve system as claimed in claim I which employs two individually moveable plates operating in co-operation with each other to block or pass air currents to produce a one-way flow upward in response to pressure changes described in the existing US patent cited above1 there being an appropriately positioned combination of plates at the underside or inlet zone of the orifice as at the upper or exhaust zone of the orifice in which the air driven power converter operates.

5. A valve system as claimed in claim 4 which protects the air driven power converter from excess air flow by moving any two plates apart a distance sufficient to allow a bypass around the orifice.

6. A valve system as claimed in claim 4 which employs an electric or hydraulic or pneumatic or manual or equivalent means of propelling each valve plate along its tracks to a position determined by a central control in response to the direction and speed of the external wind, these positions able to vary gradually from sealed together as one valve, to diametrically opposed or full open.

7. A valve system as claimed in claim 4 in which the lower inlet valve assembly may operate independently of the upper exhaust valve assembly, as may each plate in order to effect maximum work-flow through, or complete bypass around the air driven power converter.