WO2003056138A1

WO2003056138A1 - Improvement in and relating to prime movers

Info

Publication number: WO2003056138A1
Application number: PCT/GB2002/005797
Authority: WO
Inventors: Charles Neill
Original assignee: Charles Neill
Priority date: 2001-12-21
Filing date: 2002-12-19
Publication date: 2003-07-10
Also published as: GB0130892D0; AU2002352466A1

Abstract

The invention describes a prime mover comprising a housing comprising a fluid inlet and a fluid outlet, the housing enclosing first and second rotatable members, each rotatable member comprising a plurality of radially extending vanes, wherein one or more vanes of each of the first and second rotatable members are arranged, in use, to mesh as the first and second members are rotated, and wherein the fluid inlet is situated such that the fluid flow into the prime mover effects positive pressure on at least one vane of each of the first and second rotatable members such that the rotatable members are urged to rotate in opposite directions.

Description

ROTARY MACHINE

Field of the Invention

This invention relates to prime movers, combustion engines and methods of converting fluid flow into rotational motion.

Background to the Invention

There are many devices for converting energy in fluid flow into rotary motion. For example, turbines, Pelton wheels, steam expansion engines, which are examples of "prime movers" etc all convert fluid flow into rotary motion, but these are all primarily designed to utilise high input pressures or velocities and work at high thermodynamic and/or mechanical efficiencies . Such devices are frequently noisy and require large installations to house the apparatus and effectively prevent noise from reaching the outside environment. By their nature, none of these devices generally operate efficiently, if at all, under low pressures. Thus it would be advantageous to provide an apparatus which could extract small levels of energy from low pressure fluids, especially if this can be done in an environmentally acceptable manner, for example without producing undue noise or visual intrusion.

Wind turbines are known which can generate power from gentle breezes. Unfortunately, such turbines have to be located in relatively uninterrupted air flows and usually intrude visually into a landscape in which it is located. Also, aerodynamic noise created every time a blade passes the support mast on which the turbine in mounted can be quite considerable, and as this noise occurs at frequent intervals, it can be a very significant problem to persons living near the turbine.

Hydroelectric power stations are known, but most viable schemes require larger volumes of water at high pressures, falling tens or even hundreds of metres onto a series of separated rotors .

There is a great deal of untapped energy gently flowing rivers, tidal currents and breezes.

It would therefore be advantageous to be able to provide an apparatus to extract small amounts of energy from slowly flowing fluids and convert them into usable rotary motion in an environmentally acceptable manner.

It is therefore an aim of preferred embodiments of the invention to overcome or mitigate at least one problem of the prior art, whether expressly disclosed herein or not.

Summary of the Invention

According to a first aspect of the invention there is provided a prime mover comprising a housing comprising a fluid inlet and a fluid outlet, the housing enclosing first and second rotatable members, each rotatable member comprising a plurality of radially extending vanes, wherein one or more vanes of each of the first and second rotatable members are arranged, in use, to mesh as the first and second members are rotated, and wherein the fluid inlet is situated such that fluid flow into the prime mover effects positive pressure on at least one vane of each of the first and second rotatable members, such that the rotatable members are urged to rotate in opposite directions .

The vanes may be mounted on a hub, and may be integrally formed with the hub or be connected to the hub.

Preferably the inlet is positioned such that fluid can enter the housing substantially between the first and second rotatable members, preferably substantially midway between the rotatable members.

Preferably the inlet is located such that fluid is arranged to enter the housing such that it exerts simultaneous positive pressure on at least one vane of each of the rotatable members .

The inlet may be located such that fluid entering the housing first effects pressure on a vane of each of the first and second rotatable members downstream of any enmeshed vanes. Thus pressure from the fluid causes rotation of each of the rotatable members such that enmeshed vanes move downstream to be acted upon by, the fluid, and members upstream move downstream to become enmeshed vanes.

The inlet may be located below and between the first and second rotatable members. The inlet may be located in a surface of the housing below the rotatable members, and preferably substantially midway therebetween. The inlet may effect fluid flow into the housing transverse to or parallel with the rotational axes of the rotatable members. This arrangement is suitable if the fluid is a gas or liquid, which will then flow transversely from the inlet into the space between non-enmeshed vanes of the rotatable members and effect pressure on a vane of each of the rotatable members, in opposite directions, in order to rotate each rotatable member in opposite directions, to bring further vanes of each into position for pressure to be applied by gas or liquid entering the housing. This location of the inlet may prevent excessive turbulence of liquid entering the housing.

The inlet may be located above and between the first and second rotatable members. This arrangement is preferred if the fluid is gaseous or a vapour. The inlet may be located in surface of the housing above the rotatable members .

Suitably the inlet comprises an aperture in the wall of the housing.

Suitably the prime mover is dimensioned such that the distal end of the vanes of the rotatable members extend substantially to the inner surface of the housing at at least one region of the housing. Thus, the distance between the distal end of the vanes and the inner surface of at least a portion of the housing is preferably such that fluid movement therebetween is substantially reduced. This reduces fluid entering the housing from the inlet from flowing around the vanes within the housing, at least in one region, thus substantially reducing pressure loss of the fluid on the vanes.

Suitably the prime mover is constructed such that the vanes of the rotatable members have a width substantially equal to that between a front surface and rear surface of the housing. Thus the vanes preferably extend in width substantially up to the front and rear surfaces, preventing fluid flow between the sides of the vanes and the surfaces, again substantially reducing pressure loss of the fluid on the vanes .

Suitably the or each free edge of a vane, whether a distal, side or any other edge of the vane, is dimensioned to extend to a close tolerance with at least a portion of the inner surface of the housing, as the rotatable member is rotated within the housing.

At least one free edge of at least one of the vanes of the rotatable members may be coated in a friction reducing substance . Thus suitably the or each vane may extend to and abut at least a portion the inner surface of the housing, with the friction reducing substance reducing the amount of friction between the edge or edges of the vane and the surface to allow movement of the vane as the rotatable member rotates. Thus, the coating may serve as a sealing means, which in use prevents fluid from moving between the coated edge of the vane and the inner surface of the housing.

The hub of the first and/or second rotatable members may integral with the vanes, or the vanes may be connected to the hub.

The outlet preferably comprises an aperture in the housing, and is preferably located on the opposite plane face of the housing as the inlet, but may be located on the same plane face of the housing to the inlet. The outlet may be located at or towards the top of the housing, above the rotatable members when the inlet is located at or towards the bottom of the housing. The outlet may be located at or towards the bottom of the housing, below the rotatable members, when the inlet is located at or towards the top of the housing.

The outlet aperture may comprise an elongate slot.

At least one portion of the or each of the surfaces of the vanes, of the first and/or second rotatable members, which, in use, are arranged to abut when the vanes enmesh, may be coated with a sealing agent, to form an fluid tight seal between the two vanes. The sealing agent is preferably a low friction material .

Suitable materials which are both low friction materials and friction reducing materials useful for the invention include Teflon (RTM) , PTFE and the like, for examples.

The interior surface of the housing may be coated, in part or in full with a friction reducing agent, or low friction agent . The friction reducing agent and low friction agents may be as described hereinabove.

Preferably the first and second members are mounted on respective parallel first and second shafts. The first and/or second member may be rigidly connected to its respective shaft and rotatable therewith, or may be rotatably connected to the shaft.

The first rotatable member is preferably rotatably connected on the first shaft, and is freely rotatable thereabout. The second rotatable member is preferably rigidly connected to the second shaft and rotatable therewith.

In alternative embodiments the first and second members may both be rigidly connected to the respective first and second shafts and rotatable therewith.

Preferably a shaft on which is rigidly connected a rotatable member is connected to a power take up or energy generating apparatus. Both the first and second shafts may be connected to a power take up or energy generating apparatus .

The prime mover may form part of an energy generating apparatus such as a wind or water turbine, such as a windmill, or watermill, for example; or as part of an electrical or power generator for use on vehicles such as boats, caravans, motor homes, and the like, for example. The prime mover may form part of an electrical generator such as a battery charger, for example. The prime mover may form part of a compressor, such as an air compressor, which may be used for any suitable purpose including for refrigerated vehicles, trailers and containers. The prime mover may form part of a pumping apparatus, for example a filtration unit through which sewage or waste products are pumped.

The housing may be made from metal (including alloy) plastics, ceramics or carbon fibre. For larger housings metal is preferred. For smaller housings plastics or ceramics are preferred. According to a second aspect of the present invention there is provided a prime mover apparatus comprising at least two prime movers of the first aspect of the present invention operably connected such that in use fluid discharged from an outlet of at least one of the prime movers is arranged to pass into at least one other prime mover .

Rotation of a pair of first and second rotatable members in one prime mover preferably effects simultaneous rotation of the first and second rotatable members of at least another prime mover, and preferably all of the prime movers present in the apparatus .

Suitably the first and second rotatable members of all of the prime movers are co-axial on first and second shafts extending through all of the prime movers.

The first and second rotatable members of a prime mover may be set at a different radial angle on the shafts compared to the first and second rotatable members of one or more further prime movers. The degree of radial offset may depend on the number of vanes on the rotatable members of a prime mover. For example preferably when the adjacent prime movers have rotatable members comprising 6 vanes each, the degree of radial offset between vanes or rotatable members of the two prime movers is 30°.

Suitably the inlet of at least one prime mover comprises the outlet of at least one other prime mover.

The prime movers may be separated by one or more intermediate housings through which first and second shafts of the apparatus extend. Preferably the outlet of a prime mover extends through the intermediate housing and into a second prime mover, such that it forms an inlet of the second prime mover.

There may be three, four, five or more prime movers connected in series, either continuously or contiguously within the prime mover apparatus .

According to a third aspect of the present invention there is provided a combustion apparatus comprising a prime mover of the first aspect of the invention to which is connected a combustion chamber.

Suitably the combustion chamber is operably connected to the inlet of the prime mover.

Preferably the outlet of the prime mover comprises an exhaust. Alternatively the outlet may be connected to a separate exhaust member, such as a channel, port or the like, for example.

Suitably one or both of the first and second rotatable members of the prime mover are operably connected to a drive device or gear. The drive device may comprise an axle, such as the axle of a vehicle, for example. Alternatively the drive device may be a gear pump.

Suitably the combustion apparatus further comprises an air (or gas) compressor operably connected to the combustion chamber, and arranged in use to compress air and feed the compressed air into the combustion chamber. Preferably the first and second rotatable members are mounted on the first and second shafts of the prime mover, which extend into the air compressor and comprise an air compressor rotor on each shaft which mesh, in use, to effect compression of air drawn into the air compressor. Thus, rotation of the prime mover preferably effects compression of air within the air compressor.

Alternatively a separate air or gas compressor may be present in the apparatus, and may be integrally connected to the apparatus or remotely connected to the apparatus .

According to a fourth aspect of the present invention there is provided a combustion apparatus comprising a prime mover apparatus of the second aspect of the invention operably connected to a combustion chamber.

Suitably the combustion chamber is operably connected to the inlet of each of the prime movers of the invention. Preferably the apparatus comprises an air compressor, which is more preferably as described for the fourth aspect of the invention.

According to a fifth aspect of the invention there is provided a method of translating fluid pressure into rotational motion, using a prime mover of the first aspect of the invention, an apparatus of the second aspect of the invention, or a combustion apparatus of the third or fourth aspects of the invention. Brief Description of the Drawings

For a better understanding of the various aspects of the invention and to show how embodiments of the same may be put into effect, the invention will now be described by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a side sectional view of a first embodiment of the prime mover of the invention;

Figure 2 is a cross sectional view of the prime mover through the line A-A of Figure 1.

Figure 3 is a plan schematic view of a plurality of prime movers of the invention situated within a river;

Figure 4 is a side elevation schematic view of a prime mover of the invention generating electrical power in a river or tidal current;

Figure 5 is a block diagram of the prime mover of the invention producing electrical power from a steam generator in a single expansion;

Figure 6 is a block diagram of the prime mover of the invention producing electrical power from a steam generator in a double expansion;

Figure 7 is a part side sectional elevation and part perspective view of a second embodiment of the prime mover of the invention with the rotors absent; Figure 8 is a cross sectional front elevation of the prime mover of Figure 7, through the line C-C;

Figure 9 is a side sectional cross section of the prime mover of Figure 7 taken through the line A-A of Figure 8;

Figure 10 is a cross sectional side elevation of the prime mover of Figure 7 taken through the line B-B of Figure 8 ;

Figure 11 is a side elevation of a preferred embodiment of s combustion apparatus of the invention;

Figure 12 is a front sectional elevation taken through the line D-D of Figure 11;

Figure 13 is a front sectional elevation of the apparatus of Figure 11 taken through the line A-A or B-B of Figure 11; and

Figure 14 is a front sectional elevation of the apparatus of Figure 11 taken through the line C-C of Figure 11.

Description of the Preferred Embodiments

In the following description, like numerals represent like components, or components which fulfil an identical function.

We refer first to Figures 1 and 2. A preferred embodiment of a prime mover 1 of the invention comprises a casing 2 comprising a outer housing 34 having a front surface 36, which may or may not be transparent. Within the housing 34 are mounted first and second rotatable members in the form of a first rotor 3A and a second rotor 3B, which are mounted on first 6A and second 6B shafts respectively. The first and second rotors 3A, 3B are mounted such that the shafts 6A and 6B are parallel and adjacent, the shafts extending through the front surface 36 through a cavity 29 formed within the outer housing 34 and into the rear face of the housing 34. The first rotor 3A comprises an integral hub 7 from which radially extend a set of six vanes 11. The second rotor 3B comprises a second set of six vanes 12 extending radially from an integral hub 8. The first and second rotors 3A, 3B are mounted such that the vanes 11 and 12 enmesh as the rotors 3A and 3B rotate, and such that each vanes 11, 12 extends such that when the vanes 11, 12 enmesh during rotation of the rotors 3A and 3B, the vanes 11, 12 extend substantially to the opposite rotatable member's hub 7, 8 between two adjacent vanes 11, 12.

The cavity 29 of the housing 34 is dimensioned such that the vanes 11, 12 of the first and second rotors 3A, 3B extend substantially to regions of the inner surface 13 of the housing 34. The cavity 29 is constructed in the form of merged hollow cylinders having a front surface 36 at one end thereof and a rear surface at the other end thereof, and through which the shafts 6A, 6B extend. The merged cylinder orientation provides a lower apex 30 on the bottom inner surface of the cavity 29, from which extend downwardly first and second 26, 28 slopping arc portions. The merged cylinder construction also provides an upper downwardly extending apex 32 at the top inner surface 13 of the housing 34, from which extend upwardly sloping arc portions, as shown in Figure 2. The housing also includes an inlet 4 in the form of a conduit extending through the front surface 36 of the housing 34 into the cavity 29. The inlet 4 is positioned in the front surface 36 between, and below the plane of, the shafts 6A, 6B . The inlet 4 is positioned substantially above the lower apex 30 of the inner surface 13 of the housing 34.

The housing 34 also includes an outlet 5 in the form of a conduit located in the rear surface of the housing 34, substantially centrally within the housing, below the upper apex 32 of the inner surface 13 of the housing 34, and substantially midway between the rotors. The outlet 5 is also located above the plane of the shaft 6A and 6B in the housing 34. The outlet 5 consists of an outlet slot 5^', extending from an outlet pipe 5^", such that the outlet slot 5^' extends substantially behind the rotors 3A and 3B, towards the sidewall of the housing 34, as shown in Figure 2.

The shafts 6A and 6B are mounted on bearings 7 in bearing caps 8 , the bearings and bearing caps being located outside of the housing 34, as shown in Figure 1. The bearings 7 and bearing cap 8 should also include sealing means to prevent fluid entering or exiting the prime mover 1 by way of the shaft 6A and 6B.

Use of the preferred embodiment of the prime mover 1 of Figures 1 and 2 will now be described with reference to Figures 1 and 2.

The prime mover 1 is intended to translate energy from a fluid into rotational movement of the shaft 6B. A fluid, which is either pressurised, or free flowing from a moving fluid source is fed into the inlet 4 of the prime mover 1.

A description of how fluid entering the cavity 29 from the inlet 4 will be described with reference to two vanes 11 and 12, one from each of rotors 3A and 3B, as labelled ll^' and 12^' on Figure 2. In the position shown in Figure 2, the vane ll^' on rotor 3A is positioned in front of and slightly lower than the position of the inlet 4 in the housing 34, and the vane 12^' on the adjacent rotor 3B is positioned extending above the inlet 4 in the housing 34. In this position, as fluid enters the cavity 29 of the housing 34 through the inlet 4, the fluid will firstly contact the upper surface ll" of the vane ll^' , thus putting positive pressure on the vane ll^' and rotor 3A, causing the rotor 3A to rotate in one direction. As the rotor 3A rotates, the adjacent vane 9 upstream of vane ll^' rotates to abut the vane 12^' on the second rotor 3B, thereby effecting rotation of the rotor 3B in the opposite direction to that of the rotor 3A. As the rotor 3A rotates, the vane ll' moves away from in front of the fluid inlet 4, such that fluid which continues to enter the cavity 29 begins to act on both vane ll^' , and vane 10 on the opposite rotor 3B simultaneously, downstream of the vane 12', as shown in Figure 2. Thus, positive pressure is effected on both ll' and vane 10 on opposite rotor 3A and 3B simultaneously.

Further rotation of rotors 3A and 3B bring vane 12^* on rotor 3B into alignment with the fluid inlet 4, such that fluid entering cavity 29 begins to effect positive pressure on the vane 12' by way of the upper surface 12", at the same time continuing to effect positive pressure on the upper surface 11^' of the vane 11 on rotor 3A. Eventually, the vane ll^' on rotor 3A is rotated sufficiently such that the adjacent and upstream vane 9 comes into alignment with the inlet 4, such that positive pressure begins to be exerted on the vane 9.

In this way, positive pressure is effected on vanes of both rotors 3A and 3B simultaneously and alternatively throughout the rotation cycle of each, and each rotor is effected by 6 power pulses, to give a total of 12 power pulses for the prime mover 1 shown in Figures 1 and 2, such that the prime mover is subject to positive pressure for the whole of its cycle.

As well as fluid falling onto the upper surface of a vane of each of rotors 3A and 3B in turn during rotation, as the fluid drops onto the inner surface 13 of the housing 34, it contacts the upwardly extending apex 30 on the bottom of the inner surface 13, and flows down slopes 26 and 28 either side of the apex 30 to effect positive pressure on any vane 11, 12 on the rotors 3A and 3B located in the region either side of apex 30 adjacent to slopes 26 and 28.

Each of the vanes 11, 12 are provided with a friction reducing coating of Teflon (RTM) , which enable the vanes to substantially abut the inner surface 13 of the housing 34, whilst still allowing rotation of the rotors 3A and 3B. The substantial seals between the distal tips of the vanes 11, 12 and the inner surface effect substantial sealing of portions of the cavity 29 between adjacent vanes of the same rotor, as shown for example by portions 110 and 120 on Figure 2. These substantially fluid tight portions 110, 120 enable fluid to move round the cavity 29 with rotation of the rotors 3A and 3B, until the fluid is adjacent to the outlet slot 5^'. At this point, fluid passes into the outlet slot 5^' of the outlet 5, until it runs into the outlet pipe 5^", and out of the prime mover 1, as shown in Figures 1 and 2. The length of the slot 5^' enables fluid to be removed efficiently, maintaining full pressure differential of the prime mover 1.

Either one of shafts 6A and 6B may be connected to a power takeoff, such that rotation of either of shafts 6A and 6B may generate power. Thus, one of shafts 6A and 6B may be freely rotating and not connected to a power takeoff. Alternatively both shafts 6A and 6B may be connected to a power takeoff, and may be synchronised to effect power takeoff from both shafts.

The power takeoff may be connected to either or both of shafts 6A or 6B directly, or via gearing, which may be synchronised if both shafts are connected to gearing. The power takeoff may be an electrical power generator, and once turning, the rotational inertia of the generator may serve to further smooth out any irregularities in the motion of rotors 3A and 3B to deliver constant frequency power.

We refer now to Figures 3 and 4. Figure 3 illustrates a schematic view of a plurality of prime movers 1A, identical to the prime mover 1 of Figure 1, set to provide power in a water current. In Figure 3, a river 14 flowing in direction 15 between opposite banks 16 is provided with a lock 17 alongside a prime mover apparatus 18 housing three prime movers 1A, identical to prime mover 1 of Figure 1.

The prime movers 1A are orientated such that the inlets 4 of each prime mover are oriented to receive fluid flow in direction 15 down the river 14. Consequently, the outlets 5 of each prime mover 1A is located oriented such that fluid may exit the prime mover apparatus 18 and into the river 14 downstream of the lock 17, as shown in Figure 3. Each prime mover 1A is provided with a shutoff valve 19 within the inlet 4, and within the outlet 5, such that if necessary, each of the prime movers 1A may separately be closed off by the shutoff valves 19 in order to prevent operation of the individual prime mover 1A. As shown in Figure 3, the water flow 15 passes through the three prime movers 1A via each inlet 4, and out of each prime mover 1A via each outlet 5. The valves 19 within the inlets 4 may be adjustable to restrict the flow of fluid through he inlet 4 5 to control flow into each prime mover 1A. Thus, fluid flow may be controlled at different speeds through each prime mover 1A separately. An automatic control system (not shown) , measuring current frequency may automatically adjust valves 19 within the inlets 4, in order to adjust fluid flow into the housing 34 of each prime mover 1A as necessary.

If fluid flow 15 exceeds the capacity of the three prime movers 1A, excess water may be passed through the lock 17, for example by partly opening sluices in both upper and lower gates of the lock, or via a spillway (not shown) in structure 18. In periods of low fluid flow, one or more of the prime movers 1A may be shutdown, so that the fluid flow passes through the remaining unit or units only, at the correct speed in which to generate power. The use of a lock 17 allows water pressure build up such that the pressure of the water flow 15 can be increased through the inlets 4 of the prime mover apparatus 18.

We refer now to Figure 4 , which shows a prime mover 1A corresponding to the prime mover 1 of Figures 1 and 2 , located in a underwater structure 20 in a river or tidal channel 22. Here, the flow 15 may be a constant movement of a river or the reciprocal flow of tide. In the latter case, no power will be generated at slack water, but outside this period, valves 19 could be adjusted to give an essentially constant generator speed. The underwater structure 20 is of a size such that it will not disrupt waterborne travel 21.

Referring to Figure 2, the efficiency of power generation from the rotors 3A and 3B in the preferred prime mover 1 of the invention may be increased by the incorporation of sealing means, antifriction means or the like between the tips or distal edges of the vanes 11 and 12, and the inner surface 13 of the housing 34, and between the side edges of the vanes 11 and 12, rotors 3 and the front surface 36 and rear surface of the housing 34. In the case of power generation utilising water as a fluid, closely toleranced clearance between the rotors 3A and 3B, vanes 11 and 12 and the inner surface 13 of the housing 34 may be acceptable and will save on production costs. If the fluid being used is a gas at high pressure, sealing means may be necessary to conserve fluid pressure within the chamber 29 during use of the prime mover 1. In an alternative embodiment of the prime mover 1 of the invention (not shown) , the inlet and outlets 4 and 5 may be inverted, such that the inlet is located in the housing 34 towards the top of the housing, extending into an upper portion of the cavity 29. Conversely, the outlet 5 may be located in the housing 34 at a lower portion thereof, extending into the cavity 29 at a lower portion thereof. Thus in this orientation, if the fluid is a gas or vapour, as the vapour enters the cavity 29 via the inlet 4, it will act on an opposite side of the vanes 11 and 12 to that shown for Figures 1 and 2 , in order to rotate the rotors 3A and 3B in opposite directions, which directions will be opposite to those achieved when the inlet is positioned towards the bottom of the housing 34 and extends into a bottom portion of the cavity 29.

It is to be noted however, that the inlet 4 may be positioned towards the bottom of the housing 34, as shown in Figure 2 when the fluid is a gas or vapour, and the action of the prime mover 1 would be identical to that described above when the fluid is water or another liquid.

Figure 5 shows a block diagram of another use of the prime mover 1 of Figures 1 and 2. In Figure 5, the block diagram shows the prime mover 1 connected upstream to a steam generator 23, which for example can burn fuel such as wood, paraffin oil etc to raise steam, which then passes through the inlet 4 of the prime mover 1 to effect rotation of the rotors 6A and 6B as described hereinabove. One of the rotors 6A or 6B is connected to a power generator 24 which produces power 25 upon rotation of said shaft 6A or 6B. Steam passing through the prime mover 1 will condense and water and remaining steam vapour passing through the rotors 6A and 6B are ejected through the outlet 5 to the environment, or preferably recycled to the steam generator.

We turn now to Figures 6 to 10 which illustrate a second preferred embodiment of a prime mover 2 of the invention, and a preferred prime mover apparatus 18. Figure 6 illustrates a schematic block diagram of a double expansion prime mover 1 which comprises two spaced apart pairs of enmeshing rotors, axially spaced apart on shafts 6A and 6B (not shown) . The prime mover 1 includes a first housing 34 in which are located the first pair of enmeshing rotors (not shown in Figure 6) as described for Figures 1 and 2, and which includes an inlet 4 arranged to receive steam generated in a steam generator 23 connected thereto. The housing 34 also includes an outlet 5 connected to a second housing 42 which includes the second pair of spaced apart rotors (not shown in Figure 6) connected to the first and second shaft 6A and 6B . Extending from the second housing 42 is a second outlet 50 arranged to transport steam which has passed through the first 34 and second 42 housings back to the steam generator 23 in order to recycle the water. One of the shafts 6A and 6B is connected to a power generator 24 to generate power upon rotation of the rotors within the housings 34 and 42.

We turn now to Figures 7 to 10, which illustrate in more detail the double expansion apparatus 18 of Figure 6. Figure 7 shows an isometric perspective view of the prime mover 1 of Figure 6. The prime mover 1 comprises a casing 2 which includes a front surface 36, a first housing 34 which houses a first set of spaced apart rotors (not shown, but equivalent to those shown for Figures 1 and 2) , mounted on parallel first and second shafts (not shown, but equivalent to shafts 6A and 6B shown for Figures 1 and 2) . Connected to the rear of the first housing 34 is an intermediate housing 40, which separates a second housing 42 from the first housing 36. The second housing 42 comprises a second pair of enmeshing rotors 48, connected to the shafts 6A and 6B which shafts extend through the first housing 34 intermediate housing 40 and second housing 42, as shown in Figure 9. Thus extending into the first housing 34 is an inlet tube 42, as shown in Figure 8 and 9, the inlet being connected at one end to a steam generator 23 as shown in Figure 6. An outlet, in the form of a plurality of outlet apertures 40 is present in the rear face of the first housing 34, extending into the intermediate housing 40. The outlet 40 as shown in Figure 9 extends through the intermediate housing, to emerge as an inlet 44 into the second housing 42 at a bottom portion of said second housing 42. A second outlet 50 is present in the second housing 41 at an upper side portion thereof, as shown in Figure 7 and 10. The second outlet 50 is connected to an outlet pipe 52 which tracks back into the intermediate housing 40 and out through the intermediate housing back to the steam generator 23 (not shown) .

In use, steam is fed from the steam generator 23 through the inlet 4 into the first housing 36 in order to drive the rotors 3A and 3B, as described for the prime mover 1 of Figures 1 and 2 above. As the rotors are driven, this effects rotation of the shaft 6A and 6B, thereby also rotating the rotors 48 in the second housing 42. As the steam is rotated about the cavity 29 of the first housing 36, it is forced through outlet apertures 40, and into the intermediate housing 40, where it travels through the intermediate housing and out of the intermediate housing 40 through the second inlet 44 into the second housing 42. As the steam is forced into the second housing 42 it serves to drive the second set of rotors 48, thus further providing drive for the rotors 48 and 6A and 6B . The steam is then driven by the rotors 48 to the second outlet 50 and via the second outlet 50 into the outlet pipe 52 back to the steam generator 23 for recycling.

As can be seen from Figure 9, the first set of rotors 6A and 6B have vanes of a shorter width than the rotors 48 in the second housing 42. The shorter width vanes 11, 12 of the rotor 6A, 6B are suitable for the high pressure steam which is generated from the steam generator 23 and piped into the first housing 36. As the steam travels through the first housing 36 and intermediate housing 40, the pressure of the steam will drop, and the larger width vanes of the rotors 48 of the second housing 42 compensate for the drop in pressure. The prime mover apparatus 18 shown in Figures 6 to 10 may be adapted to all forms of fluid pressure or volumetric input .

We refer now to Figures 11 to 14, which show a combustion apparatus 54 utilising a double expansion prime mover apparatus similar to that described for Figure 6 to 10.

Referring to Figure 11, the combustion apparatus 54 includes a double expansion prime mover 1 as described for Figures 6 to 10, which includes a first chamber 34 in which are mounted a pair of intermeshing rotors 3A and 3B on shafts 6A and 6B, as described for Figures 6 to 10. The double expansion prime mover 1 also includes a second housing 42 which includes a second pair of rotors 48 mounted on the shafts 6A and 6B as described for the embodiments shown in Figures 6 to 10. Thus the rotors 48 and 3A, 3B are coaxial (in tandem) on 6A and 6B, but spaced apart in separate housings 34 and 42. Located behind the second housing 42 is a third housing 56, and located behind the third housing 56 is a fourth housing 58. The shafts 6A and 6B extend through the first and second housings 36, 42, through the third housing 56 and into the fourth housing 58. A combustion chamber 62 is located beneath the four housings 36, 42, 56 and 58. Located above the four housing 34, 42, 56 and 58 is an exhaust channel 60. The combustion chamber 62 is connected to the fourth chamber 58 via an inlet/outlet 64. The combustion chamber 62 is connected to the first 34 and second 42 housings by an inlet/outlet 4. The exhaust channel 60 is connected to the first and second housing 36, 42 via exhaust inlet/outlets 5. The shafts 6A and 6B located within the fourth housing 58 include a pair of meshing rotors 66 and 68 acting as a gear pump, and the portion of the shaft 6B located within the third housing 56 includes a first gear 70 meshed with a second gear 72. The gear 72 may be operably connected to a gear pump, the rotors 66 and 68, or a drive unit such as an axle of a vehicle, for example.

The fourth housing 58 also includes an air inlet 72. The combustion chamber 62 includes a fuel inlet (not shown) .

Use of the combustion apparatus 54 will now be described with reference to Figures 11 to 14. Air is drawn into the air inlet 72 of the fourth housing

58, such that it is compressed between the rotors 66 and

68 on the portions of shaft 6A and 6B within the fourth housing 58. The compressed air is forced through the outlet/inlet 64 into the combustion chamber 62 of the apparatus 54. In the combustion chamber 62 the compressed air is mixed with fuel injected through the fuel inlet

(not shown) . The fuel may be regulated by a carburettor, or fuel injector for example, and may be ignited by a spark plug or the like.

As soon as a desired quantity of fuel and compressed air is present within the combustion chamber 62, it is ignited to cause combustion of the fuel air mixture. Combustion generates a pressure wave and pressurised waste gases, which are forced through the outlets/inlets 4 into the first 36 and second 42 housings, thereby driving the rotors 6A, 6B and 48 on the shaft 6A and 6B, as described previously for the embodiments shown in Figures 1 to 10. Rotation of the rotors 3A, 3B and 48 cause the waste gases to exit the first 36 and second 42 housings into the exhaust channel 60 via the outlets 5.

Rotation of the rotors 3A, 3B and 48 causes rotation of the shafts 6A and 6B and thereby causes rotation of the rotor 70 in the third chamber 56, thus causing rotation of gear 72, in order to drive the drive unit (not shown) .

Furthermore, rotation of the shafts 6A and 6B cause further rotation of the rotors 66 and 68 in the fourth housing 58, in order to provide continuous compression of air from the air inlet 72 in the fourth housing 58. The rotor 66 and 68 are constructed in dimension to provide compressed air intake at three times the speed of the apparatus speed.

The apparatus 54 may be adapted to provide a power generator for any number of mobile or light applications, such as vehicle engines, machinery engines and the like.

In alternative embodiments a separate compressor is connected to the apparatus 54 in place of the compressor housed in fourth housing 58, and may be operated separately to the apparatus 54. Thus the fourth housing may not be present in these embodiments.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) , may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features .

The invention is not restricted to the details of the foregoing embodiment (s) . The invention extend to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A prime mover comprising a housing comprising a fluid inlet and a fluid outlet, the housing enclosing first and second rotatable members, each rotatable member comprising a plurality of radially extending vanes, wherein one or more vanes of each of the first and second rotatable members are arranged, in use, to mesh as the first and second members are rotated, and wherein the fluid inlet is situated such that the fluid flow into the prime mover effects positive pressure on at least one vane of each of the first and second rotatable members such that the rotatable members are urged to rotate in opposite directions.

2. A prime mover as claimed in Claim 1, wherein the vanes are mounted on a hub .

3. A prime mover as claimed in Claim 2, wherein the vanes are integrally formed with the hub.

4. A prime mover as claimed in Claim 2, wherein the vanes are connected to the hub.

5. A prime mover as claimed in any preceding claim, wherein the inlet is located such that fluid is arranged to enter the housing such that it exerts simultaneous positive pressure on at least one vane of each of the rotatable members.

A prime mover as claimed in any preceding claim, wherein the inlet is positioned such that fluid can enter the housing substantially between the first and second rotatable members .

7. A prime mover as claimed in any preceding claim, wherein the inlet is located below and between the first and second rotatable members.

8. A prime mover as claimed in Claim 6, wherein the inlet is located above and between the first and second rotatable members.

9. A prime mover as claimed in any preceding claim, wherein the prime mover is dimensioned such that the distal end of the vanes of each of the rotatable members extends substantially to the inner surface of the housing at at least one region of the housing.

10. A prime mover as claimed in any preceding claim, wherein the prime mover is constructed such that the vanes of the rotatable members have a width substantially equal to that between a front surface and rear surface of the housing.

11. A prime mover as claimed in any preceding claim, wherein at least one free edge of at least one of the vanes of the rotatable members is coated in a friction reducing agent.

12. A prime mover as claimed in Claim 11, wherein the coating serves as a sealing means, which in use prevents fluid from moving between the coated edge of the vane and the inner surface of the housing.

13. A prime mover as claimed in any preceding claim, wherein the outlet comprises an aperture in the housing.

14. A prime mover as claimed in any preceding claim, wherein the outlet is located in the top of the housing above the rotatable members when the inlet is located at or towards the bottom of the housing.

15. A prime mover as claimed in any preceding claim, wherein the outlet is located in the bottom of the housing, below the rotatable members, when the inlet is located at or towards the top of the housing.

16. A prime mover as claimed in any preceding claim, wherein at least one portion of the or each of the surfaces of the vanes, of the first and/or second rotatable members, which in use are arranged to abut when the vanes enmesh, is coated with a sealing agent to form a fluid tight seal between the two vanes.

17. A prime mover as claimed in any preceding claims, wherein the interior surface of the housing is coated in part or in full with a friction reducing agent, or a low friction agent.

18. A prime mover as claimed in any preceding claim, wherein the first and second members are mounted on respective parallel first and second shafts.

19. A prime mover as claimed in Claim 18, wherein the first and/or second member is rigidly connected to its respective shaft.

20. A prime mover as claimed in Claim 18, wherein the first and/or second member is rotatably connected to its respective shaft.

21. A prime mover as claimed in Claim 18, wherein the first rotatable member is rotatably connected to the first shaft and is freely rotatably thereabout.

22. A prime mover as claimed in Claim 18, wherein the second rotatable member is rigidly connected to the second shaft and rotatable therewith.

23. A prime mover as claimed in Claim 18, wherein both the first and second member are rigidly connected to the first and second shafts and rotatable therewith.

24. A prime mover apparatus comprising at least two prime movers as claimed in any of Claims 1 to 23, operably connected such that in use, fluid discharged from an outlet of at least one of the prime movers is arranged to pass into at least one other prime mover.

25. An apparatus as claimed in Claim 24, wherein rotation of a pair of first and second rotatable members in one prime mover effects simultaneous rotation of the first and second rotatable members of at least one other prime mover .

26. An apparatus as claimed in Claim 24 and 25, wherein the first and second rotatable members of all of the prime movers are co-axial on first and second shafts extending through all of the prime movers.

27. An apparatus as claimed in any one of Claims 24 to 26, wherein the inlet of at least one prime mover comprises the outlet of at least one other prime mover .

28. An apparatus as claimed in any one of Claims 24 to 27, wherein the prime movers may be separated by one or more intermediate housings through which first and second shafts of the apparatus extend.

29. An apparatus as claimed in Claim 28, wherein the outlet of one prime mover extends through the intermediate housing and into a second prime mover, such that it forms an inlet of the second prime mover.

30. A combustion apparatus comprising a prime mover of any one of Claims 1 to 23 to which is connected a combustion chamber.

31. An apparatus as claimed in Claim 30, wherein the combustion chamber is operably connected to the inlet of the prime mover .

32. An apparatus as claimed in Claim 30 or 31, wherein the outlet of the prime mover comprises an exhaust.

33. An apparatus as claimed in any one of Claim 30 to 32, wherein one or both of the first and second rotatable members of the prime mover are operably connected to a drive device or gear.

34. An apparatus as claimed in any one of Claims 30 to 33, wherein the combustion apparatus further comprises an air compressor operably connected to the combustion chamber, and arranged in use to compress air and feed the compressed air into the combustion chamber.

35. A combustion apparatus comprising a prime mover apparatus of any one of Claims 24 to 29, connected to a combustion chamber.

36. An apparatus as claimed in Claim 35, wherein the combustion chamber is operably connected to the inlet of each of the prime movers of the apparatus .

37. An apparatus as claimed in Claim 35 or 36, wherein the apparatus comprises an air compressor.

38. A method of translating fluid pressure into rotational motion, using a prime mover of any one of Claims 1 to 23, a prime mover apparatus of any one of Claims 24 to 29 or a combustion apparatus of any one of Claims 30 to 37.

39. A prime mover substantially as described herein, with reference to the accompanying drawings.

40. An apparatus substantially as described herein, with reference to the accompanying drawings .

41. A method substantially as described herein with reference to the accompanying drawings .