GB2471148A

GB2471148A - Water supply generator with tangential jet turbine

Info

Publication number: GB2471148A
Application number: GB1000687A
Authority: GB
Inventors: Damian Rayne
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-06-08
Filing date: 2010-01-15
Publication date: 2010-12-22
Anticipated expiration: 2030-01-15
Also published as: GB0909828D0; GB201000687D0; GB2471148B

Abstract

A water powered generator comprises a casing housing a turbine `impeller' which has a central liquid inlet 45, 46 in communication with a liquid supply, and at least two tangential reaction jet outlets 44a, 44b. The turbine disc has enlarged portions connecting the inlet and outlets, that are smoothly shaped to minimise turbulence. The turbine and alternator are mounted coaxially on a shaft, surrounded by an annular reservoir. The device may comprise a cylindrical housing with rubber feet, and be suitable for connection to a water supply pipe.

Description

AN AUXILIARY POWER GENERATOR

The present invention relates to a generator for the generation of electricity and to a method of operating a generator.

It is known to use an air supply such as a compressed air supply or vehicle exhaust to power an auxiliary power generator. However, this type of device requires a compressed air supply and one may not always be readily available. Water driven power generators are also known, for example hydroelectric generators and micro-hydroelectric generators. Micro-hydroelectric generators use a high velocity water jet to drive a bladed turbine wheel which spins to drive a generator. These micro-hydroelectric generators require large volumes of fast flowing falling water and are therefore not always practical where such a specific water supply is not available.

Furthermore, these generators are noisy, require lots of water and generate a large amount of waste. It is therefore desirable to provide a supplementary power generator that addresses at least some of the problems of the prior art. It is further desired to provide an auxiliary power generator that is suitable for domestic use.

According to the present disclosure, there is provided an auxiliary power generator for generation of electrical power, comprising a casing housing an impeller, the impeller including a central inlet in liquid communication with a liquid supply, at least two outlets radially spaced from the central inlet, and at least two impeller reservoirs extending between the central inlet and the at least two liquid outlets respectively, and an alternator, the impeller and alternator being mounted coaxially on a shaft, and an internal reservoir surrounding the impeller and alternator, such that in use of the generator, the liquid fills the impeller and the internal reservoir prior to admitting the working liquid supply into the generator.

An effect of the generator is that it requires only a constant supply of working liquid in order to operate and does not require falling liquid flow. It is able to generate electricity on a small scale suitable for use in either powering a pump, or if connected to a suitable water supply, to provide an auxiliary power supply for domestic use. The generator works by pressurised displacement of a working liquid in order to drive an impeller for the generation of shaft rotation, the impeller being submersed within the working liquid itself.

The impeller may comprise a generally circular casing defining at least two opposing liquid reservoirs, each reservoir being generally comma shaped in plan view, extending radially outwards from the central inlet to the circumference and over approximately half the circumference of the casing, to one of the at least two liquid outlets. The reservoir shape has the effect of increasing the liquid pressure until it exits the impeller at the liquid outlet at a relatively high pressure to that at which it enters the central inlet. The impeller reservoirs may be faired to minimise the possibility of flow separation and air bubbles developing in the reservoirs that would reduce the efficiency of the generator. As liquid exits the impeller at relatively high pressure, this rotates the impeller to produce drive shaft power.

The generator uses liquid displacement to keep any changes in the liquid pressure gradual from the generator inlet to outputting the liquid from the generator.

In an embodiment, the liquid is pressurised water.

The generator may comprise a liquid filter disposed downstream of and in liquid communication with the tank.

According to another aspect of the disclosure, there is provided a method of operating a pressure driven generator for generating electricity using a working liquid, the generator comprising an outer casing having an inlet, an outlet having an outlet valve that includes at least an open position and a closed position, the casing housing an impeller and an alternator mounted co-axially on a shaft, the impeller having a circumferential casing and including a central inlet for receiving a supply of the working liquid, at least two impeller reservoirs arranged between the central inlet and the circumferential casing and being arranged for liquid communication between the central inlet and the internal reservoir, the generator further comprising a tank surrounding the impeller and alternator to form an internal reservoir in an interior space between the tank and the impeller and alternator, the outer casing inlet being disposed in liquid communication with the impeller central inlet and internal reservoir, the method comprising filling the internal reservoir and impeller reservoirs with the working liquid whilst the outlet valve is in the closed position thereof, connecting the outer casing inlet and the outlet to a pressurised working liquid supply and opening the outlet valve to the open position thereof to start the generator.

Filling the internal reservoir also fills the impeller reservoirs, as they are open to the interior space between the tank and the impeller and alternator. Thus, with the outlet valve in a closed position, the internal reservoir fills with the liquid. The introduction of high pressure liquid into the impeller reservoirs causes the impeller to rotate as the liquid is displaced through to the reservoir. The impeller rotates the shafi to provide power to the alternator.

The generator may further include a liquid filter disposed downstream of the displacement tank and the method may comprise the further step of passing the displaced liquid through the liquid filter.

The working liquid supply may be a mains water supply.

These and other advantageous aspects of the generator will be readily understood by the skilled person upon reading the following description and accompanying drawings, in which: FIG. I is a schematic perspective view of a generator according to an embodiment; FIG. 2a is a schematic cross-sectional view of the inlet end of the generator of FIG. 1; FIG. 2b is a schematic cross-sectional view of the outlet end of the generator of FIG. 1; FIG. 3 is a perspective schematic view of the generator of FIG. 1 with the casing partially cut away for clarity; FIG. 4 is a cross-sectional view of the impeller at line X-X of FIG. 1; FIG. 5 is a cross-section of the impeller at line Y-Y in FIG. 4; FIG. 6 is a schematic representation of the operation of the generator; and FIG. 7 is a schematic representation of the casing seals from the front, rear, lefi and right perspectives.

An embodiment of the generator is shown in Figures 1, 2a and 2b. The generator is an axially arranged generator and consists of an elongate outer casing 10, inside of which is housed a liquid tank 20 into which a working liquid is supplied. In the present embodiment, the working liquid is water but it could be any other suitable pressurised liquid. The casing 10 is generally cylindrical with domed ends. The tank is also elongate and is suspended inside the casing 10 and attached thereto by a plurality of tank support structures 27 (seen in Figure 3) that extend between the tank wall 20 and the casing 10. A number of the tank support structures 27 are equi-spaced around the circumference of the tank in order to securely attach it to the casing and to provide rigidity to the generator. in the present embodiment, there are four tank support structures 27, each structure including an air vent to the ambient air for the dispersal of heat generated inside the generator, particularly from the electrical equipment. The support structures may be moulded into the casing and are faired as seen in Figure 3, so as to present the minimum disturbance to oncoming water flow through the generator during use. The casing 10 is supported externally via rubber feet 12 that are located at the domed ends of the casing and which are shaped so as to allow the generator to stand firmly on a flat surface. The rubber feet 12 also act as shock absorbers for the generator. The casing has a front portion 5 and a detachable rear portion 8 that is removable to provide access to the tank 20 and other parts of the generator for maintenance purposes. The casing 10 and tank 20 are made of moulded plastic.

The casing 10 includes a liquid inlet conduit 16 at a proximal end 15 thereof as shown in Figure 1 that may be connected to a liquid supply. The inlet conduit 16 extends axially inside the casing where it is connected to the tank 20 so as to provide liquid communication between the liquid supply and the tank 20. A tank outlet 22 is located at the distal end of the tank 20 and is connected to a liquid outlet conduit 24 that extends between the tank outlet 22 where the water or other working liquid can exit the generator during use thereof. In the embodiment shown in Figure 1, the liquid outlet conduit 24 is located at the casing distal end. An outlet valve 28, seen in Figure 2b, is provided for selectively opening and closing the liquid outlet 24 to permit or prevent liquid flow therethrough.

A drive shaft 30 extends axially inside the tank 20 between the inlet conduit 16 at the distal end of the tank and a proximal end of the tank 20 at which it is supported in a journalled bearing (not shown). Coaxially mounted on the drive shaft are an impeller 40 and an alternator 50, each mounted for co-rotation with the drive shaft 30 towards the distal end thereof Referring to Figures 2a, 2b, 4 and 5, the impeller 40 is a short cylindrical unit, axially mounted on the drive shaft 30. The impeller 40 includes a circumferential casing and a central inlet 45 through which the working liquid enters the impeller. This is made possible by the drive shaft 30 being manufactured to be hollow between the inlet conduit 16 and the central inlet 45 of the impeller 40. The hollow portion of the drive shaft 30 is connected to the inlet conduit 16 at the proximal end of the tank 20 for liquid communication between the inlet conduit 16 and the impeller 40. The inlet conduit is fixed in position and does not rotate, therefore a suitable sealed connection is required at the junction between the drive shaft 30 and the inlet conduit 16, as will be apparent to the skilled person.

The impeller shown in Figures 3, 4 and 5 is designed to permit the working liquid entering the impeller 40 to split into two flow channels, 42a, 42b, each channel tenninating at the impeller circumferential casing through impeller exits 44a, 44b.

For this purpose, the central inlet 45 includes a splitter plate 46 that divides the central inlet 45 into the two channels 42a, 42b. From the central inlet 45, the liquid is directed through the channels 42a, 42b and into two separate reservoirs 46a, 46b. The exits 44a, 44b are located at approximately 180 degrees from each other on the circumferential casing of the impeller and the reservoirs 46a, 46b oppose and interlock with each other to form a circular shape when viewed in plan as seen in Figure 4.

The reservoirs each extend radially from the central inlet 45 towards the circumference of the impeller 40 and are shaped in a sweeping curve around the circumference so as to be generally comma-shaped in plan view, the tail end of each conm-ia terminating at the impeller exits 44a, 44b, respectively. The reservoirs are rounded or faired in profile as seen in Figure 5 such that they have a smooth profile.

The gradual sweep of the reservoirs 46a, 46b from the channels 42a, 42b to the impeller exits 44a, 44b, is intended to prevent flow separation and the formation of air pockets in the reservoirs during use of the generator and also to create an increase in pressure in the liquid from the central inlet 45 to the exits 44a, 44b of the impeller.

The alternator 50 is mounted on the drive shaft 30 adjacent the impeller 40.

The alternator 50 is a lOOamp/l2volt marine use alternator such as a BalmarTM marine alternator or similar alternator in which the alternator casing is sealed for submersible use. The alternator is driven by rotation of the drive shaft 30 by the impeller 40. In an embodiment, a voltage regulator 55 is connected to the alternator 50. The alternator and regulator may additionally be contained within a housing 21 to further protect them from the water during use of the generator. The alternator outputs power to a 12 volt DC power output 53 that can be connected to a separate battery such as 2lOAmp/hr leisure marine or caravan battery. The power outputted by the generator is sufficient to power a 12 volt domestic light emitting diode (LED) lighting system of up to 20 units for a period of twenty four to forty eight hours. The power output cable 53 feeds through one of the ventilating structures 27 in order to be connected externally. The ventilation/support structures 27 are sealed tight against water as explained further below.

Downstream of the alternator/regulator 50/55 is a displacement cone 60 that Consists of a smoothly rounded conical body over which the working liquid flows during use to reach the tank outlet 22. This arrangement of the impeller 40, alternator/regulator 50/55 and displacement cone 60 is located axially inside the tank 20 such that an annular reservoir 70 is formed between the alternator 50, impeller 40 and displacement cone 60 on the one hand and the tank 20 on the other, the reservoir surrounding the impeller, alternator and displacement cone such that the working liquid can flow out of the impeller exits 44a, 44b and over the alternator casing 50 and displacement cone 60 through the tank 20 towards the tank outlet 22. The displacement cone 60 is furthermore used to alter the length of the impeller-alternator-cone arrangement 40, 50, 60 inside the tank 20. This is achieved using a simple grub screw arrangement, shown schematically in Figure 3, together with appropriate gearing for translation of the rotational screw motion to longitudinal motion of the displacement cone, as is known in the art. The position of the displacement cone should be set at the time of installation of the generator when optimising the generator setup.

The displacement cone 60 is longitudinally adjustable so as to vary the cross-sectional area of the reservoir 70 surrounding the cone 60 at the outlet end of the tank 20. The reservoir area tapers towards the tank outlet 22 such that displacing the cone axially changes the area of the reservoir 70. Displacing the cone towards the outlet end of the tank 20 decreases the reservoir area 70 whilst displacing the cone 60 away from the tank outlet increases the reservoir area. In this manner, the liquid pressure in the tank can be adjusted as necessary to provide a continuous optimal flow through the generator. The reservoir 70 is relatively large in cross section along the length of the generator such that the pressure in the liquid is low in comparison with the mains pressure. The cross sectional area of the reservoir 70 tapers towards the liquid outlet 24 so as to increase the liquid pressure back towards the mains pressure. Ideally, the water will be at mains pressure or close to it at the point it is returned to the mains conduit.

Referring now to Figure 7, the generator must be well sealed at several crucial positions in order to prevent water leakage to the generator components. This is especially important as the water supply is pressurised during use. Figure 7 is a schematic representation of the seals, which may be hard rubber 0-ring seals in an embodiment of the generator. Seals 300 are located at the support/ventilation structures 27, both inside of and outside of the casing 10, and seals 310 are provided at the inlet 16 and outlet 24.

Furthermore, seals 320 are provided at the junction of the alternator 50 and the drive shall 30 and also around the drive shaft 30 upstream of the impeller 40, to prevent water leakage from the tank 20 at the drive shaft 30. The seals are robust and ensure a watertight tank 20 and safe use of the electrical equipment.

Operation of the generator is described as follows with reference to Figure 6.

In a domestic use of the generator, the supply may be a mains water supply denoted generally as ref. 200, which must be disconnected at the service valve 210 as shown schematically in Figure 6a. As seen in Figure 6b, the generator inlet 16 is connected to mains conduit 220 using an adaptor conduit 225. The tank 20 is then filled with mains water whilst the outlet valve remains closed as seen in Figure 6c. The 0-ring seals at the interface between the drive shaft and the alternator housing prevent leakage of the water from the internal reservoir 70 into the housing the alternator 50 and regulator 55. The generator outlet is then securely connected to the mains conduit 220 as shown in Figure 6d. Once the generator is securely installed in the mains conduit 220, the outlet valve of the generator is released at the same time as the mains service valve 210 is opened in order to start the generator, as shown in Figure 6e, The water fills the reservoir 70 and the channels 42a, 42b and reservoirs 46a, 46b of the impeller and also surrounds the impeller.

The pressurised water enters the generator via the hollow drive shaft, into the impeller central inlet 45 and into the impeller channels 42a, 42b. The force of the pressurised water entering the generator displaces the water already present in the impeller channels and reservoirs 46a, 46b, causing the impeller to rotate. The impeller rotation in turn drives the alternator for the generation of electrical power. The displaced water flows through the reservoir 70 towards the liquid outlet, where the generator may be connected back to the mains water conduit.

Claims

CLAIMS1. An auxiliary power generator for the generation of electrical power, comprising a casing housing an impeller, the impeller including a central inlet in liquid communication with a liquid supply, at least two outlets radially spaced from the central inlet, and at least two impeller reservoirs extending between the central inlet and the at least two liquid outlets respectively, and an alternator, the impeller and alternator being mounted coaxially on a shaft, and an internal reservoir surrounding the impeller and alternator, such that in use of the generator, the liquid fills the impeller and the internal reservoir prior to admitting the working liquid supply into the generator.
2. An auxiliary power generator according to claim 1, in which the impeller comprises a generally circular casing defining at least two opposing liquid reservoirs, each reservoir been generally comma shaped in plan view, and extending radially outwards from the central inlet to the circumference and over approximately half the circumference of the casing, to one of the at least two liquid outlets.
3. An auxiliary power generator according to claim 1, in which the shaft is hollow between the working liquid supply and the central inlet of the impeller for liquid communication between the working liquid suppiy and the impeller.
4. An auxiliary power generator according to claim 1, in which the internal reservoir has a cross-sectional area that is variable.
5. An auxiliary power generator according to claim 4, further comprising a displacement element that is longitudinally displaceable for varying the cross-sectional area of the internal reservoir.
6. An auxiliary power generator according to claim I in which the liquid is water.
7. An auxiliary power generator according to claim 1, in which the working liquid supply is a pressurised water supply.
8. A method of operating a pressure driven generator for generating electricity using a working liquid, the generator comprising an outer casing having an inlet, an outlet having an outlet valve that includes at least an open position and a closed position, the casing housing an impeller and an alternator niounted co-axially on a shaft, the impeller having a circumferential casing and including a central inlet for receiving a supply of the working liquid, at least two impeller reservoirs arranged between the central inlet and the circumferential casing and being arranged for liquid communication between the central inlet and the internal reservoir, the generator further comprising a tank surrounding the impeller and alternator to form an internal reservoir in an interior space between the tank and the impeller and alternator, the outer casing inlet being disposed in liquid conmiunication with the impeller central inlet and internal reservoir, the method comprising filling the internal reservoir and impeller reservoirs with the working liquid whilst the outlet valve is in the closed position thereof, connecting the outer casing inlet and the outlet to a pressurised working liquid supply and opening the outlet valve to the open position thereof to start the generator.
9. A method as claimed in claim 8, wherein the working fluid is water.
10. An auxiliary power generator substantially as described herein and with reference to the accompanying claims.
11. A method substantially as described herein and with reference to the accompanying claims.