GB2417294A - Micro combined heat and power plant - Google Patents

Abstract

An annular reaction turbine 12 integral with boiler 7 produces rotation from steam raised by natural gas combustion 2 under heating cone 4 and the central flue 5 with heat deflector cone 11. Centrifugal fan 26 in the lower bearing 6 assists saturated steam up the boiler wall. Water 28 enters the boiler through gap 27 between the boiler wall and the heating cone. The expansion and centrifugal force send the steam to the turbine where the steam is constrained by sprung outlet vanes 14 which open at pre-determined pressure resulting in a tangential reaction force producing rotation. At a pre-determined rotational speed the centrifugal clutch 18 will engage, driving the shaft 23, a reduction gear 19 and the hollow shafted generator 20. Steam condenses in chamber 15 for return to tank 3 with baffles 21 and condensing jacket 8,9 coolant provides hot water. Provides domestic electrical power and hot water.

Description

241 7294 Micro Annular Reaction Steam Turbine.

Description.

The invention of this turbine is intended to provide efficient, rotary and heat energy, at the domestic or small commercial level, there is a large scope at this end of the market for a rotary power source. To summarise the principle of this design is that small steam power engines do not have to be scaled down versions of large ones, to be efficient they must be totally new concepts. The rotational force produced, and the by- product of condensing hot water, are dual assets of this design that can be used for the increasing requirement to obtain more efficient domestic energy. Some domestic Combined Heating and Power units (Micro C.H.P.s) are currently available but are of limited efficiency due to the use of water cooled reciprocating engines.

The turbine, fuelled by natural gas wherever possible, if not available then by L.P.G. (bottled gas), or any other suitable fuel, is of vertical form and constructed in one-piece including the turbine disc and boiler. The flue pipe runs through the centre, which makes it the spine of the entire assembly. To achieve the 'only one major moving part concept' the boiler is open bottomed to allow the ingress of water, the gas burner applies heat through the heating cone which sets off a natural water current raising the saturated steam into the boiler chamber. Only a small gap between the bottom of the boiler and the heating cone is essential to achieve a virtual sealing effect. The selection of a more heat absorbing material of the turbine disc compared with the boiler body is to increase the natural heat difference between the top and bottom of the boiler, the purpose being to obtain some super-heating of the steam. The steam then enters the annular reaction turbine disc, to overcome the problem of inertia, the turbine outlets are covered by a sprung outlet vane, allowing the pressure to build up before they open and create a tangential reactive force which produces rotation. A number of steam channels, through the turbine disc are used and are of an internal aerofoil section, assisting the tangential reaction force to produce rotation. When the revolutions of the disc increase centrifugal forces become increasingly important. To assist the saturated steam in its centrifugence the support legs of the lower bearing are vane shaped. The steam then enters the condensing chamber, which is surrounded by the condensing jacket for the primary purpose of creating low pressure at the exit of the turbine. The pressure drop is achieved naturally by converting the steam back to water. The hot condensing water is then used, (for example), for washing or heating.

The resulting forces produced rotate the hollow drive shaft, a centrifugal clutch and reduction gear would then drive either a hollow shafted electricity generator or other devices mounted directly above. An alternative would be to drive any remotely mounted device. The reduction gear would probably be used on most application due to the high revolutions produced and /or any application requiring high torque.

The high speeds the turbine will run at require accurate balancing of the complete rotating assembly prior to being fitted into the static components. The final product will then be enclosed in a cabinet.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings in which: FIGURE I is a vertical cross-section of the whole assembly.

FIGURE 2 shows the plan view of the annular turbine disc.

FIGURE 3 is a centre-line cross section through the turbine channel.

FIGURE 4 shows an elevation of the lower bearing support.

FIGURE 5 is a schematic layout of a typical control system.

As shown in Figure 1 the fuel pipe 1 supplies gas or other suitable fuels to Me burner 2 which is ignited and heats the boiler cone 4, the exhaust gases rise up the copper flue pipe 5. The heat baffle 11 deflects some of the escaping heat onto the turbine top plate 13 before the remainder exhausts out the top of flue pipe 5. The boiler cone 4, water tank 3 and the outer condensing jacket 9 are fixed together with watertight joints, the materials used would probably be stainless steel and aluminium.

The water level 28 in the water tank 3 is just above the top of the heating flames, as the water approaches boiling point the water will rise up the exterior of the boiler cone 4 passing through the lower bearing 6 supports 26 into the boiler 7. It is proposed that the turbine top plate 13 which contains the upper bearing 16 and the annular turbine disc 12 are made from copper, due its high thermal conductivity, for the purpose of reducing some the saturation within the steam rising up the boiler, hence increasing the steam pressure.

The steam pressure builds up within the turbine channels, at a predetermined pressure the sprung outlet vanes 14 open creating a tangential reaction force. The complete turbine and boiler assembly ( consisting of parts 6, 7, 12, 13,14,16 and 26) starts to revolve.

As the speed increases centrifugal forces begin contributing.

The lower bearing 6 supports 26 commence throwing the saturated steam onto the tapered wall of the boiler 7, the centrifugal force causes the steam to climb up to the turbine discs 12 and 13, this action greatly adds to the turbines efficiency.

The steam enters the condensing chamber 15, which is surrounded by the internal 8 and the external 9 condensing jackets. The inner jacket 8 would have a rubber seal 29 against the bottom of the turbine annulus, preventing the uncondensed steam leaking back to the turbine. The condensing jackets 8 and 9 are fed by number of cooling water pipes 10 situated at various positions around the upper and lower circumferences. The hot condensed steam water then drains back into the water tank 3. The hot condensing water is then piped 10 away to be used for washing and/or heating. Steam is prevented from escaping by the steam seal 17 located at the upper bearing 16.The water baffles 21 in the water tank 3 are to reduce the 'whirlpooling' effect within the tank at high speeds.

When a predetermined revolution speed has been achieved the centrifugal clutch 18 will drive the hollow drive shaft 23 whose bearings 22 will also be located on the flue pipe 5. The turbine will only be efficient at high speeds therefore most applications will require reduction gearing 19. Probably the most common use will be to drive a 230V generator 20, but other options are possible.

Figure 2 is a plan view of the annular turbine 12 showing how the aerofoil channels 29 turn the steam through 90 degrees, a reactive force builds up on the sprung outlet vanes 14, which open, as at 14A and create the clockwise revolution of the turbine. The top and bottom of the channels can be very slightly angled downwards towards the periphery, at high speed the reactive force would lift the whole assembly creating virtual weightlessness and hence very low friction.

Figure 3 shows the depth of the channels 28 in the turbine annulus and how the top of the boiler 7 adjoins the bore smoothly with a steam proof joint.

Figure 4 Is an enlargement of the lower bearing 6 support and centrifugal Fan 26, clarifying how the saturated steam passes from the outside of the heating cone 4 through the windows 25 into the boiler 7. A predetermined number of centrifugal fan blades 26 are deployed to assist the movement of the steam. 27 shows how the small gap between the boiler 7 bottom and the heating cone 4 uses the natural boiling current of liquids to raise the water level 28 up the heating cone 4 from the water tank 3 and into the boiler 7.

Figure 5 Is a schematic layout indicating some of the some of the safety control devices that would be required. From the diagram the following table has been derived: Item No. Control name Where applied Valve operated 32 Pressure release valve Boiler 7 Mechanical 33 Flame thermocouple Burner 2 Fuel valve 30 A 34 Water level Tank 3 Flow valve 31 Thermal cut-out Flue pipe S Fuel valve 30 A 36 Water thermostat Water pipes 10 Fuel valve 30 D 37 Steam pressure Condenser 15 Fuel valve 30 B 38 R.P.M. limiter Turbine disc 13 Fuel valve 30 C 18/8/04

Claims (8)

1) An annular turbine that produces rotary energy from a tangential reactive force created by escaping vapour.

2) A turbine as claimed in claim 1 where the channels through the annular turbine ring turn the vapour through 90 degrees converting centrifugal forces to tangential forces.

3) A turbine as in claims 1 and 2 where the expanding vapour is preferably steam and provided by a heat process where natural gas has a distinct advantage.

4) A turbine as in claims 1 and 3, driving for example an electricity generator whilst providing the by-product of hot water.

5) The preferred layout for achieving claim 3 is to use an integral turbine and boiler assembly to take advantage of an 'only one major moving part' philosophy.

6) To achieve claim 5 the boiler must be open bottomed to allow the ingress of water which is facilitated by a small gap that is controlled by a natural boiling current.

7) Where the ideal materials used in claim 5 are stainless steel for the boiler and copper for the turbine obtaining additional heat radiation at the turbine.

8) A turbine as described above and illustrated in the accompanying drawings.