GB2129060A

GB2129060A - Vertical axis windmills

Info

Publication number: GB2129060A
Application number: GB08328246A
Authority: GB
Inventors: Roy Sidney William Spicer
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-10-28
Filing date: 1983-10-21
Publication date: 1984-05-10
Also published as: GB2129060B; GB8328246D0

Abstract

The windmill has vanes 13 which are connected by horizontal members 15 to a vertical rotatable shaft 18 mounted in bearings 20, 23 which allow the shaft 18 to move vertically but which resist radial movement, the weight of the vanes 13, members 15 and shaft 18 being transmitted to a float 10 floating in liquid 11 contained in a container 12. <IMAGE>

Description

SPECIFICATION Vertical axis windmills This invention relates to vertical axis windmills.

Previously proposed vertical axis windmills are limited in their size since the rotatable structure must be supported by one or more bearings of sufficient strength to withstand, not only forces due to the wind, but also the weight of the rotatable structure itself. Furthermore, such bearings are expensive, require lubrication, and the rotatable structure supported by the bearings must be finely balanced so as not to excessively strain the bearings.

According to the present invention there is provided a vertical axis windmill comprising a plurality of vanes movable about a vertical axis and connected to a vertical rotatable shaft located on said axis, each vane being supported by a float member floating in a liquid contained in a container.

An embodiment of this invention, as described hereinbelow, has a float member which is annular, the float member supporting each of the vanes.

The annular float is at least partially immersed in a reservoir of the liquid, which for example, may be in the form of an annular container. There may, for example, be four vanes which are supported at points on the float which are diametrically opposed. The vanes may be connected to a beam extending transversely of the vertical shaft. The shaft is supported by a bearing which allows the shaft and the vanes to freely move in a vertical and rotational direction but not in a sideways direction.

Hence, in embodiments of this invention the rotating structure is supported in a vertical direction by the liquid in the moat, thus enabling iarge vanes, as compared with vanes of previously proposed windmills, to be employed.

A skirt may be attached to the outside and inside perimeter of the part of the float which is above the level of the liquid. The drive shaft which is disposed along the vertical axis, may be connected to an electrical generator via a gear box so that electrical energy may be generated from the wind when the vanes and thus the shaft are caused to rotate.

Some embodiments of the invention will now be described, by way of examples, with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of a float member; Figure 2 shows a part sectional side view of a vertical axis windmill according to the present invention; Figure 3 shows a diagrammatic perspective view of the windmill of Figure 2, having four vanes; Figure 4 shows a perspective view of another embodiment of a windmill according to the present invention, having a different arrangement of vanes to that of Figure 3; Figure 5 is a side elevation of yet another embodiment of a vertical axis windmill according to the present invention; Figure 6 is a plan view of the windmill of Figure 5; Figure 7 is a perspective view of the windmill of Figure 6 when static; and Figure 8 is a perspective view of the windmill of Figure 6 when rotating.

Figure 1 shows a float member 10 which is in the form of an annular float of rectangular crosssection capable of floating in a liquid. The float member 10 is of suitable dimensions so that it remains afloat when a plurality of vanes and beams are mounted thereon as hereafter described. The windmill shown in Figure 2 comprises the float member 10, which is shown to be partially immersed in a liquid 11 contained in a container structure 12, a plurality of vertical vanes 13 being mounted on the float member 10 by means of vertical supports 14.The vanes 13 are mounted on the float member 10 in pairs, each vane 13 or a pair being connected to the other vane 13 of the pair by means of a horizontal beam 1 5 which extends parallel to a diameter of the float member 10, the vanes 93 being secured to each end of the beam 1 5 at their mid-length position. The vanes 13 of each pair are also connected together by means a cable 16, each end of which is secured one of the vanes 1 3 at a point remote from the float member 10. The cable 1 6 prevents the vanes 1 3 from moving outwardly from the vertical axis when the windmill is rotating.

The tension in the cable 1 6 is adjustable by means of a cable tensioner 1 7 which has screwthreaded holes at each end, engaged by screwthreads provided on two ends of the cable 1 6. By rotating the cable tensioner 1 7 relative to the cable 1 6, the tension in the cable 1 6 can thereby be adjusted. The beam 1 5 is connected at its midpoint to a vertically disposed drive shaft 18, the other end of which is connected to a gear box 1 9.

The vertically disposed drive shaft 1 8 lies along the vertical axis about which the vanes 1 3 rotate when the windmill is in use. The drive shaft 18 passes through a cylindrical bearing 20, which allows the drive shaft 1 8 to freely move in a vertical direction but supports the drive shaft 1 8 in a sideways direction. The vertical drive shaft 1 8 is additionally supported by means of a frame 21, which is itself supported on the ground or on support structure in the central region of the structure 12 thus forming an annular moat in which the float member 10 floats.The drive shaft 1 8 passes through a bearing 23 carried by the frame 21 which, similarly to the cylindrical bearing 20, allows vertical movement of the drive shaft 18 therethrough but supports the drive shaft 1 8 in a sideways or radial direction. The end of the drive shaft 18 remote from the end connected to the beam 1 5, is connected to an electrical generator (not shown) via the gear box 19. This is done by connecting the armature of the generator to the gear box 1 9 by means of a suitable transmission system (not shown), which passes through a conduit 24. The conduit 24 passes out of the structure 12 so that power may be transferred, by way of the transmission system, from the windmill to the generator.Alternatively, the drive shaft 1 8 can drive an oil pump which drives a fluid motor for driving an alternator.

Although Figure 2 only shows one pair of the vanes 13, this embodiment comprises two pairs of vanes 13, the beam 1 5 of one pair being disposed orthogonally to the beam 1 5 of the other pair (see Figure 3). The mid-points of both beams 1 5 intersect one another at the point through which passes the vertical axis. Furthermore, as mentioned above, the beam 1 5 is connected to the vertical drive shaft 8 at this point. This is done by way of bolts (not shown) which fasten a hub member 25 to each beam 1 5 and to the vertical drive shaft 1 8.

The above described arrangement is not limited in size by the bearings 20 and 23 since the weight of the beams 15, shaft 18 and the vanes 13 is supported by the float member 10. However, the heavier the beams 15, shaft 18 and vanes 13 are, then a correspondingly larger float member 10 is required to support them. Also shown in Figure 2 is a skirt 30 which is attached to a portion of the float member 10 which is above the level of the liquid, the skirt 30 forming an enclosure above the surface of the liquid in the vicinity of the float member 1 0. This enclosure reduces the risk of the liquid freezing at the liquid/float member boundary during cold weather.

The float member may be arranged to drive an electric generator by way of a drive means 31. The drive means 31 comprises a roller 32 which engages an annular platform 33 projecting from the outside perimeter of the float member 10.

Friction between the roller 32 and the platform 33 drives the roller 32 and provides the means whereby power is transferred from the float member 10 to the generator (not shown). The drive means 31 may be provided instead of the gear box 1 9 and generator or in addition thereto.

Referring now to Figure 3, both pairs of the vanes 13, which are oriented orthogonally to one another, are illustrated. The vertical axis windmill of Figure 3 is shown without the annular container structure 12, the purpose of Figure 3 being, principally, to illustrate the arrangement of the vanes 13. In this case, the vanes 13 are constructed in the form of semi-circular sheets of, for example, a plastics material. The orientation of each of the vanes 13 is as shown, and is such that wind acting on the windmill in the direction of, for example, arrow A causes the windmill to rotate.

Figure 4 shows an alternative construction of vanes 13. In this case, the vanes 13 are constructed from rectangular shaped sheets of material which are connected, at their corners, onto the beams 15 and the poles 4 in the manner shown. Wind acting on the windmill in the direction of, for example, an arrow B, causes the corresponding vane 13 to fill in a manner similar to that of a sail. The windmill is therefore caused to rotate whereby a generator may be driven in the manner described hereinabove. The sheet material from which the vanes 13 are formed may be canvas or any other suitable material.

The vanes 1 3 in the embodiment of Figures 1 to 3 may be designed so that they automatically move to a feathered or inoperative position upon the force of the wind exceeding a predetermined force to provent the windmill becoming damaged and they may also be designed so that the windmill becomes self-starting.

The embodiment shown in Figures 5 to 8 comprises a container 40 for the liquid in which a float 41 floats. Supported by the float 41 are vertical posts 42 which, at their upper end, are connected to horizontal members 43 arranged in pairs, the members 43 of each pair being parallel.

At the intersection of the pairs of members 43 there is provided a plate 44 through which extends a vertical shaft 45 to which the plate 44 is fixed. The shaft 45 is carried in bearings (not shown) provided on fixed structures 46 which is supported from a central support 47 provided in the centre of the container 40. The bearings are arranged similarly to the bearings 20, 23 of Figure 2 and allow the shaft 45 to move vertically but restrain vertical movement of the shaft 45.

Pivotably connected to each end of each pair of members 43 is a vane 48 which consists of a tubular member open at each end which is cutaway along part of its length to form part circular section portions 49. Each vane 48 is hingedly connected at 50 to a tie rod 51 which, at its other end, is hingedly connected at 52 to a slide member 53 slidably mounted on the shaft 45 but rotatable therewith. The upper end of the shaft 45 is provided with an end cap 54 to which are connected coil springs 55 connected at their other end to the slide member 52.

When the windmill starts to rotate, the centrifugal force acting on the vanes 40 cause them to swing out about their hinge connections, as shown in Figure 8. This outward swinging movement is initially resisted by the coil springs 55 through the tie rods 51 and slide member 53 which ensure that the vanes 40 swing out in unison thus maintaining balance and preventing out of balance forces occurring.

In all of the embodiments described, the float can be provided with one or more vanes which are immersed in the liquid then enabling any swirl or rotational movement of the liquid to act on the float to keep it rotating under its own momentum when operating in gusting wind condition.

Instead of using an annular float, it is possible for each vane to be supported by an individual float suitably shaped to reduce resistance of the water to its movement.

The container 12, 40 may be formed of concrete and may be portable when empty.

Claims

1. A vertical axis windmill comprising a plurality of vanes movable about a vertical axis and connected to a vertical rotatable shaft located on said axis, each vane being supported from a float member floating in a liquid contained in a container.

2. A vertical axis windmill as claimed in claim 1, in which the float is annular.

3. A vertical axis windmill as claimed in claim 1 or claim 2, in which each vane is connected to arms extending from the vertical shaft.

4. A vertical axis windmill as claimed in any preceding claim, in which the vanes are fixed in a vertical position.

5. A vertical axis windmill as claimed in any preceding claim, in which the vanes are interconnected by tie wires or rods.

6. A vertical axis windmill as claimed in any one of claims 1 to 3, in which the vanes are pivotably mounted so as to be movable between a vertical position and a position in which they lie at an angle to the vertical axis.

7. A vertical axis windmill as claimed in claim 6, in which the vanes are connected by rods to a slide member vertically movable along said vertical axis.

8. A vertical axis windmill as claimed in claim 7, in which the slide member is downwardly movable against the force of resilient means.

9. A vertical axis windmill as claimed in claim 8, in which said resilient means comprise a spring or springs.

10. A vertical axis windmill as claimed in any preceding claim, in which each vane is substantially semi-circular in transverse crosssection.

11. A vertical axis windmill as claimed in any one of claims 1 to 4, in which the vanes each comprise of a rectangular sheet of material disposed at an angle to the vertical axis.

12. A vertical axis windmill as claimed in any preceding claim, in which the container is circular and has a central portion which supports bearing structure for the vertical shaft.

13. A vertical axis windmill as claimed in any preceding claim, in which the float is provided with a skirt located above the level of the liquid in the container.

14. A vertical axis windmill as claimed in any preceding claim, in which float is drivingly connected to drive means through which it drives an electrical generator.

15. A vertical axis windmill as claimed in any one of claims 1 to 14, in which the vertical shaft is drivingly connected to a hydraulic pump which drives a motor for driving an electrical generator.

16. A vertical axis windmill as claimed in any preceding claim, in which the float is provided with a vane or vanes which extend into the liquid.

17. A vertical axis windmill substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3, Figure 4 or Figures 5 to 8 of the accompanying drawings.