GB2240433A

GB2240433A - Magnetic heat engine

Info

Publication number: GB2240433A
Application number: GB9001910A
Authority: GB
Inventors: Eric Shaw
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-01-27
Filing date: 1990-01-27
Publication date: 1991-07-31
Also published as: GB9001910D0

Abstract

A magnetic heat engine using heat as a switching medium to vary the permeability of a magnetic material portions of which are within a magnetic field. Varying the disposition of the thermal field relative to the magnetic field produces continuous forward or reverse motion. A multiple rotor assembly is disclosed. More than one heat exchanger per rotor may be used and a heat recovery arrangement is shown.

Description

MAGNETIC HEAT ENGINE This invention relates to the production of mechanical energy from a source of heat.

Heat engines in their many forms are the principle means of converting sources of heat energy into mechanical energy.

Present heat engines have their maximum theoretical efficiency defined by Kelvin as T1-T2 where T1 T1 = absolute temperature of a source T2 = absolute temperature of a receiver The efficiency of any heat engine operating from a low temperature source must, therefore, be low.

The magnetic heat engine described in this invention does not use the heat as a source of energy but as a switch, utilising the change of state around the 'Curie'point (of magnetic materials) to provide a controllable torque in the devices described.

The use of magnetic materials around their Curie temperature to provide mechanical movement by the application of heat has been described in technical papers as early as the nineteen thirties. This invention takes us beyond simple movement to continuous movement and hence energy.

A descr-~ion of the features of the Invention follows and refers to the attached zrawings:- Figures í and 2 show views of the simplest form of the engine.

figures 3 and 4 show views of the magnetic circuit and heat exchanger.

Figure 5 shows a cross section of the heat exchanger.

Figure 6 illustrates the use of multiples of the simple engine to allow a wide range of source temperatures to be utilized Figure 7 illustrates the use of multiple magnetic circuits and heat exchangers on a single disc engine.

Figure 8 shows a schematic diagram of the heat flow of a four disc machine witr multiple magnetic circuits and heat exchangers on the appropriate discs.

FIGURES 1 and 2 A shaft 1 mounted in suitable bearings has the following assembly firmly attached - a centre portion 4 of non-magnetic material: an annulus of thermal insulating material 3: and an outer annulus of magnetic material of a chosen 'Curie'temperature 2. temps 2, 3 and 4 are fixed together to form a single disc.

A magnetic circuit 5 with a heat exchanger 6 is mounted so that the jaws of the device contain the magnetic material 2. The magnetic circuit 5 and exchanger 6 are mounted on a stationary frame (not illustrated) so that the disc assembly is free to revolve within the poles of the magnetic circuit.

Heat/....

Heat is applied to the heat exchanger 6 via the input and output connections 7.8. and the magnetic material 2 is heated. With the heat exchanger centrally positioned in 5 no motion of the disc will take place.

With the heat exchanger 6 moved towards the left within the jaws of the magnetic circuit 5, the heating pattern of the disc will be asymmetrical to the magnetic field pattern and anticlockwise rotation of the disc 2 will take place. Movement of the heat exchanger 6 to the right within the Jaws of the magnetic circuit 5 will cause clockwise motion of the disc 2 to take place. The speed of rotation will vary with the degree of offset of the heat exchanger 6 about the centre line of the magnetic circuit 5 for a given load on the shaft 1.

Note In a simple disc machine it is assumed that natural cooling of the disc will take place before the heated portion has to re enter the magnetic field.

FIGURES 3, 4 and 5 The magnetic circuit 5 can be energised by either a permanent magnet or an electrical coil 9. The heat exchanger 6 slides into the jaws of the magnetic circuit 5 and is capable of adjustment to the left and right of the centre line of the magnetic circuit. Heat in the form of hot gases or liquids can be applied to the heat exchangers via the connections 7 and 8. Either connection can be the input or the output.

The outer casing of the heat exchanger 10 is manufactured of thermal insulating materials. The inner of the heat exchanger 11 is of copper or a material of similar good thermal conductivity. The gap 12 between the heat exchanger and the disc 2 is lined with metal wire or tape in the form of bristles or leaves secured to the heat exchanger 11 to provide a low friction high thermal conductive path from the heat exchanger 11 to the disc 2.

FIGURE 6 Multiple discs 2 mounted on a shaft 1 and capable of spinning within the jaws of the magnetic circuit/heat exchanger assemblies 5 and 6 allow a range of temperatures to be applied to the system depending upon the number of discs mounted on the shaft and the grading of the'Curie' temperatures of the discs 2. The heat input would be from the left hand side and would feed through each heat exchanger towards the right with a reduction of the input temperature to each heat exchanger from left to right.

The'Curie' temperature of each disc (by choice of alloys) would grade from left to right to match the temperatures provided by the particular heat exchanger 6.

FIGURE 7 This view of the disc 2 shows multiple magnetic circuits 5 and heat exchangers 6 and also additional heat exchangers 6 in this case used as coolers.

These coolers become necessary to ensure the disc 2 is cooled prior to entering the next magnetic circuit. Figure 7 shows the arrangement for clockwise rotation of the disc 2.

FIGURE 8 Here/...

Here we have a schematic diagram of the heat flows in a machine with four discs 2, D1 D2 D3 D4 and with multiple magnet/heat exchangers 5 and 6 on three of the discs and coolers 6 on all four discs. Cl C2 and C3 are standard (ie not described in this patent) heat exchangers.

The hot fluid is passed through the four heat exchangers (shown as squares) associated with discs D1 D2 D3 and D4 respectively and looses temperature progressively. The fluid is now passed through the heat exchanger C1 to lower the temperature of the fluid sufficiently to cool disc D4 on the return pass. The fluid now flows into the coolers (shown as circles) and both cools the discs and picks up heat from D4 D3 D2 and D1. The fluid now returns via the heat exchangers associated with discs D2 D3 and D4 and into cooler C2 returning via the coolers associated with D4 D3 and D2. This sequence is repeated until the fluid is passed to EXHAUST.

The virtue of the method of heating and cooling described is that the overall efficiency is much increased by the recovery of heat from the discs via the coolers. The improvement in output achieved by the multi-pass system over a single pass system with four discs is (in theory) 2.5 times.

Note This heat flow logic can apply to any number of discs in combination with any number of magfet/heat exchangers 5 and 6 and any number of coolers 5.

Claims

1 A magnetic heat engine using heat as a switching medium to vary the permeability of a magnetic material portions of which are within a magnetic field to produce continuous motion.

2 A magnetic heat engine as in Claim 1 where, as the thermal field is offset around the centre line of the magnetic field, variable forward and teverif speeds are produced.

3 A magnetic heat engine as in Claim 1 and Claim 2 wherein multiple discs of graded 'Curie' temperatures, with heat exchangers fed in series from the heat sources, form a compound system on a single shaft.

4 A magnetic heat engine as in Claim 1 and Claim 2 wherein multiple heat exchangers associated with magnetic fields and coolers are distributed about a single disc.

5 A magnetic heat engine as in Claim 2, Claim 3 and Claim 4 wherein multiple discs on a common shaft are served by multiple heat exchangers associated with magentic fields and coolers.

c A magnetic heat engine as in Claim 5 wherein heat recovery by the use of the coolers within a heat flow system forms a multi-compound engine.

Amendments to the claims have been filed as follows 1A particular arrangement of a magnetic heat engine using heat as a switching medium to vary the permeability of a magnetic material portions of which are within a magnetic field to produce continuous motion.

2 A magnetic heat engine as in Claim 1 where, the thermal field is capable of being offset to either side of the centre line of the magnetic field, producing variable forward and reverse speeds.

3 A magnetic heat engine as in Claim 1 and Claim 2 wherein multiple discs of graded 'Curie' temperatures, with heat exchangers fed in series from the heat sources, form a compound system on a single shaft, thus allowing utilisation of a wide range of source temperatures.

4 A magnetic heat engine as in Claim 1 and Claim 2 wherein multiple heat exchangers associated with magnetic fields and coolers are distributed about a single disc, thus increasing the output proportionately.

5 A magnetic heat engine as in Claim 2, Claim 3 and Claim 4 wherein multiple discs on a common shaft are served by multiple heat exchangers associated with magnetic fields and coolers, thus increasing the source temperature range and the output.

6 A magnetic heat engine as in Claim 5 wherein heat recovery by the use of the coolers within a heat flow system forms a multi-compound engine, thus optimising the overall efficiency of the system.