Elias, Gregory E.
| 1. | Boiler comprising a heating chamber (14) provided with an inlet tube (1 1), an outlet tube (12) and at least a surface transmitting heat to the fluid to be heated, characterized in that such surface comprises a metalhc drum (7) heated by eddy currents induced by a rotating cylinder (1) fitted in the drum (7) and outwardly covered with a plurahty of permanent magnets (5). |
| 2. | Boiler according to the previous claim, characterized in that the permanent magnets (5) are arcanged on the outer surface of the rotating cylinder ( 1 ) regularly spaced and with alternate polarities. |
| 3. | Boiler according to claim 1, characterized in that the permanent magnets (5) are ananged on the outer surface of the rotating cylinder ( 1 ) in horizontal lines with alternate polarities. |
| 4. | Boiler according to any of the previous claims, characterized in that the permanent magnets (5) are separated each other by an insulating material (6). |
| 5. | Boiler according to any of the previous claims, characterized in that the rotating cylinder (1) is driven by a variable speed motor (4). |
| 6. | Boiler according to the previous claim, characterized in that the drum (7) is capable of rotating owing to the magnetic induction produced by the magnets (5), whereby the rotation speed of the drum (7) is adjusted by braking means. |
| 7. | Boiler according to the previous claim, characterized in that one of the two edges of the drum (7) is provided with a toothing (16) engaged in a toothed wheel (17) connected to such braking means. |
| 8. | Boiler according to the previous claim, characterized in that the braking means comprise an oleodynamic pump (18) connected in series by an hydraulic circuit ( 19) to an oil tank (20) and to a throttle valve (21) for the oil flow. |
| 9. | Boiler according to the previous claim, characterized in that the circuit (19) comprises a safetyvalve (22) parallel connected to the throttle valve (21 ). |
| 10. | Boiler according to any of the previous claims, characterized in that the outer surface of the drum (7) is provided with thrust means ( 15) for the fluid to be heated. |
| 11. | Boiler according to the previous claim, characterized in that said thrust means ( 15) comprise a plurahty of blades. |
| 12. | Boiler according to any of the previous claims, characteiized in that the permanent magnets (5) are made of a material comprising neodymium. |
DESCRIPTION
The present invention relates to a boiler with permanent magnets, and in particular to a boiler wherein the heat necessary to the fluid heating is produced by eddy currents (also named Foucault currents) induced by a rotating cylinder comprising a plurahty of permanent magnets and fitted in a metallic drum.
Boilers are known to comprise one or more heating elements transmitting heat to the fluid to be heated or evaporated, which flows in contact with such elements. In the known boilers, a unit, e.g. an electrical or gas unit, must be provided, which supplies a specific amount of thermal energy such as to heat or evaporate the fluid flowing therein. The known boilers are thus relatively complicated, need constant maintenance and further consume a remarkable amount of energy.
Object of the present invention is therefore to provide a boiler free from such drawbacks, namely a boiler of simple manufacture and maintenance wherein the thermal efficiency is as high as possible. Such an object is achieved by a boiler having the characteristics disclosed in claim 1. Thanks to the heat produced by magnetic induction in the boiler according to the present invention, conventional heating units, complicated and hard to control, are no longer necessary. Thus both the use and the maintenance are remarkably improved with respect to the known boilers.
Further advantages and characteristics of the boiler according to the present invention will be evident to those skilled in the art from the following detailed description of some embodiments thereof with reference to the attached drawings wherein:
- Fig. 1 shows a longitudinal section schematic view of an embodiment of the boiler according to the present invention; - Fig. 2 shows a cross-sectional schematic view of the boiler in Fig. 1 ;
- Fig. 3 shows a front schematic view of an embodiment of the boiler magnetic cylinder; and
- Fig. 4 shows a front schematic view of a second embodiment of the boiler magnetic cylinder.
Referring to Fig. 1 and Fig. 2, it can be seen that, according to an embodiment of the present invention, the boiler comprises a cylinder 1, preferably made of ferromagnetic steel, to the bases whereof two shafts 2,2', rotatably mounted on two roller bearings 3,3', are fastened, coaxially with the cylinder. One of the two shafts is keyed to a motor 4 whose rotation speed can be adjusted by known control means (not shown in figure).
A plurahty of permanent magnets 5, preferably parallelepiped-shaped, is arranged on the outer surface of rotating cylinder 1, regularly spaced and with alternate polarities. Such magnets are made of materials having high magnetic induction and high residual coercive force, such as e.g. the neodymium permanent magnets. The "chequered" arrangement of permanent magnets 5, clearly visible in Fig. 3, causes the flux lines arising from a magnet to go back in the adjacent magnets and to be thus all linked together. By this arrangement an uniform magnetic field of high intensity is obtained around rotating cylinder 1. Permanent magnets 5 are preferably separated each other by an insulating material layer 6.
On the outside of rotating cylinder 1 a drum 7 of electroconductive material, preferably aluminium, is coaxially arranged, rotatably mounted on shafts 2,2' by means of a plurahty of rollers 8. The inner surface of drum 7 is suitably arranged at a miriimum distance from permanent magnets 5 so that the whole drum 7 is immersed, without remarkable dispersions, in the magnetic field produced by magnets 5.
Drum 7 is in turn coaxially fitted in a cylindrical shell 9, also preferably made of aluminium, outwardly coated with an insulating material layer 10 and provided at its ends with an inlet tube 11 and an outlet tube 12 for the fluid to be heated. The tightness between drum 7 and shell 9 is secured by a pair of watertight bearings
13,13'.
The space between the outer surface of drum 7 and the inner surface of shell 9 forms a chamber 14 wherein the fluid to be heated is heated. On the outer surface of drum 7 a plurahty of blades 15 is fastened, oriented such as to pump such fluid from inlet tube 11 to outlet tube 12 by the rotation of drum 7.
One of the two edges of drum 7, preferably that on the opposite side from motor 4, is provided with a toothing 16 engaged in a toothed wheel 17. Such toothed wheel 17 is keyed on the hub of an oleodynamic pump 18 connected in series by an hydraulic circuit 19 to an oil tank 20 and to a throttle valve 21 for the oil flow. Said circuit 19 further comprises a safety-valve 22, parallel connected to valve 21, acting to compensate sudden pressure changes, if any, within the same circuit.
During the use, cylinder 1 together with magnets 5 is set in rotation at a constant speed by motor 4, thus producing a rotating magnetic field. Thanks to the magnetic force induced by magnets 5 according to Lenz law, drum 7 rotates in the same direction of rotation as cylinder 1, thereby setting in motion blades 15 and pumping the fluid to be heated, contamed in chamber 14, from inlet tube 1 1 to outlet tube 12. Operating on valve 21 it is possible to adjust the oil flow within hydraulic circuit 19 and, accordingly, the energy necessary to the working of pump 18, driven by toothed wheel 17 engaged in toothing 16 of drum 7. By opening or closing valve 21 it is thus possible to adjust the braking action of hydraulic circuit 19 on the rotation speed of drum 7 according to the rotation speed of cylinder 1, wherefore such drum warms up owing to the eddy currents induced by the rotating magnetic field produced by the relative rotation of cylinder 1. By acting on motor 4 and on valve 21 it is possible to control the rotation speed of cylinder 1 and drum 7 respectively, thereby adjusting very precisely the thermal energy supply to the fluid to be heated. Furthermore, such supply may be kept constant irrespective of the fluid flow in heating chamber 14. In fact, should it even be necessary to decrease or increase the fluid flow in chamber 14 owing to external causes, it would still be possible to adjust the heat supphed thereto by decreasing or increasing the rotation speed of cylinder 1. By using a braking system of the above-mentioned type it is possible to precisely set how much magnetic energy is turned into fluid thrust motion and how much into heat, and this makes the optimization of the boiler efficiency possible. In another embodiment of the boiler according to the present invention, it is possible to place the permanent magnets on the rotating cylinder not in the manner above-disclosed and shown in Fig. 3, namely regularly spaced and with alternate
polarities, but in another manner, e.g. in horizontal hnes and with alternate polarities, as shown in Fig. 4, provided that in any case the magnetic field produced by the magnets is variable during the rotation of cyhnder 1.
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