EP0760198A1

EP0760198A1 - Device for heating a medium

Info

Publication number: EP0760198A1
Application number: EP96905661A
Authority: EP
Inventors: Kamal Alavi
Original assignee: Enviro EC AG
Current assignee: Enviro EC AG
Priority date: 1995-03-17
Filing date: 1996-03-18
Publication date: 1997-03-05
Also published as: AU4936596A; AU2065195A; WO1996029845A1; CA2190360A1; CN1153591A; WO1996029844A1; JPH10503617A

Abstract

The invention concerns a device (10) for heating a solid or liquid medium (11), the device having a rotating part (15, 18) with, disposed round its circumference, several permanent magnets (22, 24) which generate a magnetic field in which the electrically conducting medium (11) is located. The magnetic field of these permanent magnets (22, 24) radiates out approximately radially. The rotation of the rotating part results in a relative motion between the magnets and the medium, thus producing eddy currents in the magnets and hence heating of the magnets. Used as the medium (11) is electrically conducting water which is passed through a coil (14) wound round the rotating part and separated by a given distance from the rotating part. The coil has an inlet and an outlet (35, 36) which are connected to a line which is connected on the outlet side to a consumer and comes back in a closed loop to the inlet side again. The heating device (10) can be used to supply heat extremely efficiently to a medium.

Description

Heating device for heating a medium

The invention relates to a heating device for heating a medium, with a plurality of permanent magnets arranged next to one another, which generate a magnetic field, in the area of which an electrically conductive material is arranged and a linear and / or rotary relative movement can be generated between the material and the permanent magnets , which heats the material.

In a generic heating arrangement according to CH-PS 662 691, which is used in a turbomolecular pump, a rotor is arranged in a high vacuum-side interior of a housing, on which rotor disks are attached, which are also attached to the cooperate stator washers attached to the housing. In order to accelerate the desorption of the surfaces on the high vacuum side, the components provided with these surfaces are heated. For this purpose, in this heating arrangement the rotor is heated by eddy currents which result from the interaction of its own rotation with a magnetic field, the field lines of which run perpendicular to the rotor axis. The magnetic field is generated by means of a permanent or electromagnet attached outside the housing, the field lines of which run perpendicular to the rotor axis. With this heating arrangement, only a limited heating output is possible.

In a further known device according to the document DE-A-1 106 440, in one embodiment variant, a rotatable bell made of ferromagnetic material is arranged in the bottom of a boiler which is used to generate steam and which is made of a highly conductive material. On the circumferential surface of this bell, permanent magnets are provided, which emit a radial magnetic field in alternating pole order. The container surrounding the bell has a ring which surrounds the permanent magnets at a short distance and which is likewise made of ferromagnetic material, for example soft iron. When the bell is turned, the permanent magnets arranged on its circumference cause the eddy currents generated to heat the container and the ring surrounding it. The latter transfer the heat to the water in the tank. However, the heat transferred with this device does not result in optimal heat transfer to the medium water to be heated.

In contrast, the present invention was based on the object of creating a heating device of the type described in the introduction, by means of which a better heat transfer and thus an increased degree of efficiency for heating a medium is achieved compared to the known solutions. Furthermore, this device should be suitable for various areas of application. According to the invention, the object is achieved in that a medium, in particular an electrically conductive liquid or a gas, is provided as the electrically conductive material, which is guided by the magnetic field generated by the permanent magnets and is heated by the eddy currents generated therein.

In a very advantageous embodiment, the permanent magnets are arranged on the circumference of a rotor, from which the magnetic field is radiated approximately radially and the medium is guided inside or outside this rotor, the relative movement being effected by rotating the rotor.

In another preferred embodiment, the permanent magnets on the end face of a rotating disk are arranged such that they generate a magnetic field radiating in the direction of the disk axis of rotation and the medium is placed at a distance from at least one end face of the disk.

With this heating device according to the invention, an almost lossless and unexpectedly high power can be transferred to the medium heated by the permanent magnets.

Exemplary embodiments of the invention and further advantages thereof are explained in more detail below with reference to the drawing. It shows:

1 shows a schematic longitudinal section through a heating device according to the invention,

2 shows a cross section through the heating device according to FIG.

3 shows a schematic cross section through an alternative embodiment of a heating device according to the invention,

4 shows a plan view of the rotating disk provided with permanent magnets according to FIG. 3, 5 shows a variant of a partially shown line coil in plan view and FIG. 6 shows the line coil in cross section along the line VI-VI according to FIG. 5.

1 shows a heating device 10 provided for heating a liquid medium 1 1, which essentially consists of a housing 12, a rotor, a conduit coil 14 guided around the latter and containing the medium 1 1, and a drive unit 13. The rotor comprises a shaft 15 which is rotatably mounted in the housing 12 and a drum 18 which is concentrically attached to it by means of flanges 34. The housing 12 has a cylindrical outer shape and has a base 16 by means of which it can be placed on a floor or the like and can be attached to it if necessary. Furthermore, this housing 12 is preferably provided on its entire inner surface with thermal and, if appropriate, sound insulation 32, 33. The housing 12 is also formed in two or more parts in order to be able to mount the rotor therein. The drum 18 is fastened on both sides to a flange 34, which are held on the shaft 15 in a rotationally fixed manner. The rotor formed with these is, as mentioned, rotatably mounted in the housing 12 and coupled to the drive unit 13, which has, for example, an electric motor 17 and a deflection gear 19. Of course, a cylindrical body could also be provided instead of a drum 18.

According to the invention, a plurality of permanent magnets 22, 24 arranged next to one another and a helical coil 14 which is guided helically around the drum 18 and with the electrically conductive medium 11 flowing through them are provided on the circumference of the drum 18. Between these permanent magnets 22, 24 and the medium 11 located in the region of the magnetic field generated by them, a rotational relative movement is generated between them when the drum 18 rotates. The permanent magnets 22, 24 thus pass the medium 1 1 in succession and generate eddy currents therein cause the medium to heat up. Preferably, a plurality of magnets 22, 24 are inserted within a recess 18 'in the axial direction of the drum 18, these magnets advantageously being arranged with the same poles on the outer side.

According to FIG. 2, the permanent magnets 22, 24 are arranged on the circumference of the drum 18 preferably at the smallest possible distance from one another and alternately provided on the outside with a north (+) or south pole (-), as a result of which these magnets Continuously acting loop-shaped magnetic fields radiate within a certain bandwidth, which cause the eddy currents in the medium in this bandwidth when there is relative movement.

These permanent magnets 22, 24 are expediently inserted in the recesses running parallel to the axis of rotation, which are provided on the circumference of the drum 18, and are held by a fastening ring 18 "which surrounds the drum. This fastening ring 18" is advantageously made of a non-magnetic material manufactured and can be placed over the drum after the magnets have been placed around the drum. The drum 18 in turn is advantageously made of a non-metallic material.

The permanent magnets 22, 24 are each formed in a rectangular rod shape, with several being arranged one behind the other in a recess 18 'in the drum 18 such that the permanent magnetic field generated by them is each radiated approximately radially from the drum 18 and in one loop each enters the adjacent opposite poles again approximately in the radial direction. The medium 11 and with it the line coil 14, which is fixed in the housing 12, are arranged at a defined distance from these magnets, so that they are located within the magnetic field generated by them. This distance is advantageously chosen to be very small, ie only a few millimeters. In the present example, the line coil 14 has a rectangular cross section and the distances between the adjacent windings are kept as small as possible so that unused gaps are created in which the magnetic field is present but not the medium to be heated.

In this heating device 10 according to FIGS. 1 and 2, a large number of magnets 22, 24 in, evenly distributed, are provided on the drum 18, which is provided with an outside diameter of approximately 300 mm and a length of approximately 500 mm the smallest possible distance from each other, each having a height of 20 mm and a width of 10 mm, and five same-pole magnetic rods are inserted one behind the other per recess. The drum 18 rotates at a speed of approximately 3000 rpm. In principle, at a speed of approximately 1000 rpm. achieved sufficient heating of the medium. At a speed of approx. 3000 rpm, the external diameter of the drum of approx. 300 mm results in a relative speed of approx. 47 m / s.

The permanent magnets 22, 24 are made from a commercially available material, preferably from neodymium, from a strontium-ferrite, a strontium-cobalt alloy or from another material suitable for the respective application. It is self-evident that the stronger the magnetic field generation per surface unit is provided in such a permanent magnet, that consequently the greater the heating in the medium is effected with otherwise constant conditions. The line coil 14 is preferably formed from non-magnetic plastic. However, it could also be made from an electrically conductive material, for example from a copper alloy, from chromium steel, aluminum or a noble metal, such as platinum or the like. It is advantageously wound around the drum several times.

A chemical additive, for example potassium, or another additive with the same effect is advantageously added to the electrically conductive water. In addition, Greater heat transfer is achieved when the water in the line is let through in a turbulent flow.

As mentioned, the two-part housing 12 is provided on the inside with an insulation layer 32, 33 which, in addition to the heat and sound insulation, is preferably additionally provided with insulation, such as, for example, or a lead foil, which shields the electromagnetic fields from the outside is. The inside of the housing could also be clad with a non-magnetic steel sleeve.

The rotor 25 is formed by the drum 18 as a flywheel and the energy transmitted by the drive unit can thus advantageously be exhausted. As a result, the rotor continues to run for a while when the drive is switched off. This effect increases the heavier the drum is built.

The medium provided as electrically conductive water is conveyed through the conduit coil 14, which is helically guided around the drum 18 and attached to the housing 12, in the sense of a continuous-flow heater, the conduit coil 14 having an inlet side 35 and an outlet side 36, which are indicated. A line leading directly or indirectly to a consumer is connected to the latter, which line is led back from the outlet side 36 in a closed circuit back to the inlet side 35. This heating device 10 is therefore particularly suitable for heating a house, in which the line is either led directly through the radiators or through the floors of the house or indirectly into a storage tank. The water stored in the latter is thereby heated, which is then brought into circulation. In the same way, the line can be led into a boiler or a similar vessel for heating the water contained therein or another medium. Furthermore, a control device, which is known per se and is not shown in more detail, is advantageously provided, by means of which the drive unit and also a pump which conveys the heated water through the line coil 14 and which is also not illustrated can be switched on and off. In addition, for safety reasons, an emergency switch is provided, upon actuation of which the rotor stops immediately and becomes effective in particular if a set temperature of the line coil is exceeded, for example if the medium would no longer be conveyed for any reason.

In the case of a heating device 40 according to FIG. 3 and FIG. 4, a rotating disk 45 is arranged on both sides of an annular line coil 46, which has uniformly distributed permanent magnets 42, 44 on the end face 45 '. The line snake 46 runs parallel to the rotary disks 45, which are fastened on a drive shaft 43, which can be rotated by a drive member, not shown. The permanent magnets 42, 44 are arranged relative to one another in such a way that they each radiate a magnetic field approximately in the direction of the axis of rotation 41. The two rotating disks 45 are of identical design and their adjacent magnets are equipped with a north and a south pole on the mutually facing end faces, as a result of which a part of the magnetic field is perpendicular to the opposite disk and a part in a loop the two adjacent, opposite-pole magnets 44 on the same disk in turn occur approximately in the axial direction. The electrically conductive line coil 46 and thus the likewise conductive medium 11 are placed at a minimal distance from the end faces 45 'of the disks 45, so that they again lie in the magnetic field generated by the magnets 42, 44 . When the rotary disks 45, which are connected to one another via the shaft, rotate, eddy currents arise in the line coil 46 and in the medium, which cause the medium to be heated as desired. The rotary disks are advantageously housed in a housing (not shown in detail) analogous to that according to FIG. 1. According to FIG. 4, the magnets 42, 44 are fastened to the outer circumference of a respective rotating disk 45 and a certain number of magnets are arranged at the smallest possible distance from each disk. Starting from a radial inlet side 47, the line coil 46 is once led around the shaft 43 and then guided via the radial outlet side 48 to a consumer. This heating device 40 is suitable for applications in which there is little space required for it.

5 and 6 show part of a line coil 50, which could be arranged analogously to the coil which is guided around the drum 18 of the heating device 10. In order to generate a turbulent flow of the medium flowing through it, this line coil 50 has a bent tube 54, in which transverse guide elements 55, 56, 57, 58, 59 which run radially to it and are fixed in the middle of the Tube 54 are held on a concentrically guided in this round body 52. These guide elements 55, 56, 57, 58, 59, which are round or different in cross section, are offset perpendicular to the tube axis at an angle, for example 72 ° as shown, and are also arranged at a distance from one another in the axial direction. Due to the formation of such guide elements, preferably over the entire length of the line coil 50, the medium is given a turbulent flow without the medium being significantly throttled in this tube 54. Of course, this line coil could also be provided with a means for generating a turbulence flow differently than shown.

In connection with the exemplary embodiments set out above, it should be pointed out in principle that eddy currents in electrically conductive materials arise in time-dependent changes in a generated magnetic field, the eddy currents not leaving the conductive material. Therefore, only the particularly liquid or gaseous medium is advantageously made electrically conductive. forms, however, the line coil is advantageously made of a non-conductive material, for example plastic.

A rotary relative movement between the magnets and the medium could also be generated in that both the line coil 14 and the drum 18 would advantageously be rotated in the opposite direction of rotation. The line coil could also be guided helically or in another manner within the drum.

Of course, this drum 18 as well as the magnets could be constructed differently. Practice has shown that the number of permanent magnets should be as large as possible for maximum power transmission, as a result of which more pulses per unit of time would be realized at a given speed of rotation of the drum. The drum could also be formed from a multipole ring, which is alternately provided on the outside on the circumference with a north and a south pole.

In principle, a linear or a combined linear and superordinate rotary relative movement could be generated between the magnets and the medium. The permanent magnets could also be arranged stationary and the relative movement could only be generated by the medium.

The areas of application of the above-described heating devices are also not limited to the above-mentioned ones, but can be used for a wide variety of areas in which thermal energy is required. Some particularly suitable uses are mentioned here, for example refrigerators, air conditioning systems, car engines, chemical or medical devices.

Claims

PATENT CLAIMS

1. Heating device for heating a medium, with a plurality of permanent magnets (22, 24, 42, 44) arranged next to one another, which generate a magnetic field, in the area of which an electrically conductive material is arranged and between the material and the permanent magnets (22, 24 , 42, 44) a linear and / or rotary relative movement can be generated, as a result of which the material is heated, characterized in that a medium (11), in particular an electrically conductive liquid or a gas, is provided as the electrically conductive material the magnetic field generated by the permanent magnets (22, 24, 42, 44) is guided and it is heated by the eddy currents generated in it.

2. Heating device according to claim 1, characterized in that the permanent magnets (22, 24) are arranged on the circumference of a rotor and alternately a north (+) or south (-) pole is provided on the outside and the magnetic field is approximate is radially radiated, the medium being guided inside or outside of this rotor.

3. Heating device according to claim 2, characterized in that electrically conductive water is provided as the medium (1 1), which is passed through a helically arranged around the rotor line coil (14), subsequently on the outlet side (36, 48) a consumer and in a closed circuit back to the inlet side (35,47).

4. Heating device according to claim 2 or 3, characterized gekennzeich¬ net that the rectangular or other permanent magnets (22,24) each parallel to the axis of rotation on the outside of the drum (18) distributed over its entire circumference with preferably without Arranged at a distance from one another and loaded alternately with a north or south pole.

5. Heating device according to claim 4, characterized in that the permanent magnets (22, 24) are inserted in the recesses (18 ') running parallel to the axis of rotation on the circumference of the drum (18) and are held by a fastening ring (18 ") enclosing the latter .

6. Heating device according to claim 5, characterized in that the drum (18) is made of a non-metallic material.

7. Heating device according to claim 1, characterized in that the permanent magnets (42, 44) are arranged distributed on the end face of a rotary disc (43), of which the magnetic field extends approximately in the direction of the axis of rotation of the rotary disc (43) is emitted, and the medium (11) is guided through a line coil (46) arranged parallel to the rotary disc (43).

8. Heating device according to claim 7, characterized in that a line coil (46) fed with electrically conductive water is wound in a circular or different shape on a plane running parallel to the rotating disc (45), the outlet side (48) of which nem end user and in a closed circuit is fed back to the inlet side (47) of the rotary disc (45).

9. Heating device according to claim 7 or 8, characterized gekennzeich¬ net that a rotating disc (45) is arranged on both sides of the line coil (46), which rotates independently of one another or by means of only one drive shaft (43) by a drive member can be.

10. Heating device according to one of claims 7 to 9, characterized ge indicates that the rotary disc (45) at least on one end face (45 ') has a number of uniformly distributed on its outer circumference permanent magnets (42,44), which from ¬ alternately loaded with a north (+) or south (-) pole.

1 1. Heating device according to one of the preceding claims, characterized in that the permanent magnets (22, 24; 42, 44) are strung together without spacing.

12. Heating device according to one of claims 3 to 9, characterized ge indicates that the line coil (50) has means for generating a turbulent flow of the medium flowing through it.

13. Heating device according to claim 12, characterized in that transverse generators (55, 56, 57, 58, 59) are arranged one after the other to generate the turbulent flow within the line coil (54).

14. Heating device according to one of the preceding claims, characterized in that the rotor or the rotary disc with a speed between 1 '500 and 4000 U / min. is rotated.

15. Heating device according to one of claims 1 to 10, characterized in that an electrically conductive chemical additive, such as, for example, potassium, is added to the medium provided as water.

16. Heating device according to one of the preceding claims, characterized in that the permanent magnets and the medium are surrounded by a housing (12) which on the inside has a heat, sound and / or one of the electromagnetic fields shielding insulation (32,33).