Abstract
A device for industrial drying of a suspension or solution containing a solid material is provided, comprising a rotatably mounted cylinder having electrically conductive properties and comprising a surface for receiving the suspension or solution, and an inductor adapted to heat the cylinder inductively. The inductive heating causes that the suspension or solution received on the surface of the rotatably mounted cylinder dries and the solid material is left. Furthermore, further devices, a system, a device package, and a method for industrial drying of a suspension or solution are introduced.
Claims
1. A device (100, 300, 301, 302, 303) for industrial drying of a suspension or solution containing a solid material, comprising: a rotatably mounted cylinder (110, 310) having electrically conductive properties, wherein the rotatably mounted cylinder (110, 310) is formed as a rotatably mounted disk and arranged vertically in the direction of the largest extension thereof, and the disk comprises a surface for receiving the suspension or solution; an inductor (120, 320, 321, 322, 323) adapted to heat the cylinder (110, 310) inductively, wherein the inductive heating causes that the suspension or solution received on the surface of the rotatably mounted cylinder (110, 310) dries and the solid material is left.
2. The device (100, 300, 301, 302, 303) with the features of claim 1, wherein the inductive heating further causes that the rotatably mounted cylinder (110, 310) is heated at least surficially.
3. The device (100, 300, 301, 302, 303) with the features of claim 1, wherein the inductor (120, 320, 321, 322, 323) is arranged at a distance to the surface of the rotatably mounted cylinder (110, 310).
4. The device (100, 300, 301, 302, 303) with the features of claim 1, wherein the rotatably mounted cylinder (110, 310) comprises an axis of rotation on which it is rotatably mounted, and wherein the inductor (120, 320, 321, 322, 323) is adapted to surround the cylinder (110, 310) at two opposite sides of the surface along and/or orthogonally to the axis of rotation.
5. The device (100, 300, 301, 302, 303) with the features of claim 1, wherein the rotatably mounted cylinder (110, 310) comprises an axis of rotation, and wherein the inductor (120, 320, 321, 322, 323) is arranged coaxially to the axis of rotation.
6. The device with the features of claim 1, wherein the rotatably mounted cylinder (110, 310) comprises a heterogeneous electrical conductivity and/or magnetic permeability such that the rotatably mounted cylinder (110, 310) is inductively heated more intensely surficially.
7. The device (100, 300, 301, 302, 303) with the features of claim 1, further comprising a voltage source adapted to supply the inductor (120, 320, 321, 322, 323) controllably with an electric alternating voltage so as to heat the rotatably mounted cylinder (110, 310) consistently.
8. The device (100, 300, 301, 302, 303) with the features of claim 1, wherein the inductor (120, 320, 321, 322, 323) is designed to be tubular so as to receive a coolant there through, whereby the inductor (120, 320, 321, 322, 323) is cooled.
9. The device (100, 300, 301, 302, 303) with the features of claim 1, wherein the rotatably mounted cylinder (110, 310) comprises a side face forming along the direction of the largest extension of the rotatably mounted cylinder (110, 310), and wherein the inductor (120, 320, 321, 322, 323) comprises an elongated electrical conductor wound along the direction of the largest extension of the rotatably mounted cylinder (110, 310) such that the wound elongated electrical conductor covers at least half of the side face.
10. The device (100, 300, 301, 302, 303) with the features of claim 1, further comprising further inductors adapted to heat the rotatably mounted cylinder (110, 310) inductively, wherein the one and the further inductors are wound circularly, spirally or triangularly, and wherein the one and the further inductors are distributed along the circumference of the cylinder and the direction of the largest extension of the rotatably mounted cylinder (110, 310).
11. The device (100, 300, 301, 302, 303) with the features of claim 1, wherein the inductor (120, 320, 321, 322, 323) comprises an elongated electrical conductor wound along the direction of the largest extension of the rotatably mounted cylinder (110, 310) and the circumference of the cylinder such that the wound elongated electrical conductor comprises a varying winding density along the circumference of the cylinder.
12. The device (100, 300, 301, 302, 303) with the features of claim 1, wherein the inductor (120, 320, 321, 322, 323) is arranged integratedly within the rotatably mounted cylinder (110, 310).
13. The device (100, 300, 301, 302, 303) with the features of claim 1, wherein the rotatably mounted cylinder (110, 310) comprises a shaft, and wherein the shaft is drivable via a direct coupling.
14. The device (100, 300, 301, 302, 303) with the features of claim 1, further comprising an application device (350) adapted to apply the suspension or solution on the surface of the rotatably mounted cylinder (110, 310).
15. The device (100, 300, 301, 302, 303) with the features of claim 1, further comprising a removing device (340) adapted to remove the left solid material from the surface of the rotatably mounted cylinder (110, 310).
16. The device (100, 300, 301, 302, 303) with the features of claim 8, further comprising a cooling system adapted to supply and discharge the coolant to/from the inductor (120, 320, 321, 322, 323).
17. A system (1000) for industrial drying of a suspension or solution containing a solid material, comprising: a device with the features of claim 16; and a heat exchanger (360), wherein the cooling system is connected to the heat exchanger (360) so as to cool the coolant and to heat the suspension or solution.
18. A device for industrial drying of a suspension or solution containing a solid material, comprising: a cylindrical pipe having electrically conductive properties and comprising an inner jacket face for receiving the suspension or solution; an inductor adapted to heat the cylindrical pipe inductively, wherein the inductive heating causes that the suspension or solution received on the inner jacket face of the cylindrical pipe dries and the solid material is left.
19. A device for industrial drying of a suspension or solution containing a solid material, comprising: a conveyor belt having electrically conductive properties and comprising a surface for receiving the suspension or solution; an inductor adapted to heat the surface inductively, wherein the inductive heating causes that the suspension or solution received on the surface of the conveyor belt dries and the solid material is left.
20. A device package (200, 201, 202) for industrial drying of a suspension or solution containing a solid material, comprising: a plurality of rotatably mounted disks (210) having electrically conductive properties, wherein each rotatably mounted disk comprises a surface for receiving the suspension or solution and is arranged vertically in the direction of the largest extension thereof, and wherein the rotatably mounted disks (210) are arranged along an axis of rotation at a distance to each other; inductors (220, 221, 222) adapted to heat the rotatably mounted disks (210) assigned to them inductively, wherein the inductors (220, 221, 222) are arranged between the plurality of rotatably mounted disks (210), and wherein the inductive heating causes that the suspension or solution received on the surfaces of the rotatably mounted disk dries and the solid material is left.
21. A method for industrial drying of a suspension or solution containing a solid material, comprising the following method steps: receiving the suspension or solution on a surface of a rotatably mounted cylinder (110, 310) having electrically conductive properties, wherein the rotatably mounted cylinder (110, 310) is formed as a rotatably mounted disk and arranged vertically in the direction of the largest extension thereof; and inductively heating the rotatably mounted cylinder (110, 310) so as to dry the received suspension or solution such that the solid material is left.
22. The method with the features of claim 21, wherein the inductive heating is carried out at least surficially in the rotatably mounted cylinder (110, 310).
23. The method with the features of claim 21, further comprising the following method steps: applying the suspension or solution on the surface of the rotatably mounted cylinder (110, 310); and removing the left solid material.
24. The method with the features of claim 21, wherein the rotatably mounted cylinder is a rotatably mounted disk.
Description
[0075] Preferred embodiments of the present invention will be explained in detail by means of the following drawings.
[0076] There show:
[0077] FIG. 1 a perspective view of a first embodiment of the device in accordance with the invention;
[0078] FIG. 2 a side view of a first embodiment of the device in accordance with the invention;
[0079] FIG. 3 a top view of a first embodiment of the device in accordance with the invention;
[0080] FIG. 4 a front view of a first embodiment of the device package in accordance with the invention;
[0081] FIG. 5 a front view of a second embodiment of the device package in accordance with the invention;
[0082] FIG. 6 a front view of a third embodiment of the device package in accordance with the invention;
[0083] FIG. 7 a side view of a second embodiment of the device in accordance with the invention;
[0084] FIG. 8 a side view of a third embodiment of the device in accordance with the invention;
[0085] FIG. 9 a side view of a fourth embodiment of the device in accordance with the invention;
[0086] FIG. 10 a lateral view of a fifth embodiment of the device in accordance with the invention;
[0087] FIG. 11 a schematic view of an embodiment of the system in accordance with the invention.
[0088] FIGS. 1 to 3 show different views of a first embodiment of the device 100 in accordance with the invention for the industrial drying of a suspension or solution. The device 100 comprises a rotatably mounted disk 110 having electrically conductive properties, wherein the disk 110 is of circular design, and an inductor 120. The disk 110 is provided with a centrically arranged opening so as to push it onto a shaft and fasten it. Preferably, the disk 110 contains steel, ferritic stainless steel, copper, and/or graphite. Other electrically conductive materials are, however, also conceivable. The diameter of the disk 110 is preferably 500 to 1500 mm. Particularly preferred, the disk thickness is 5 to 15 mm. The inductor 120 comprises an elongated conductor, e.g. a wire. In order to avoid pollution of the electrically conductive parts of the inductor 120, a non-conductive and non-magnetic coating may be applied. Also conceivable is a housing (not illustrated) of a non-conductive or magnetizable material which encloses the inductor 120. Suitable materials for protection of the inductor 120 are, for instance, glass, plastics, or artificial resins. Furthermore, the inductor 120 is wound around the disk 110. The wound arrangement may surround the disk surface, preferably half the disk surface. In the embodiment of FIG. 1 the winding of the inductor 120 starts at the level of the horizontal disk diameter and reaches to the upper edge of the disk 110. The contactable end portions of the inductor are positioned at a distance on a front side of the disk 110. The distance between the individual wound conductor layers of the inductor 120 may be between 10 and 50 mm. In order to keep the centrical opening of the disk 110 free, the elongated conductor comprises circular portions which are arranged concentrically over the opening. The radii of the circular portions increase with increasing distance from the centrical opening of the disk 110. Between the disk surface and the elongated conductor a gap is available, so that the rotatably mounted disk 110 is freely movable and can be rotated. A preferably small distance of the inductor 120 from the rotatably mounted disk 110 is advantageous since this determines the degree of efficiency of the induced heat introduction. Preferably, the distance of the inductor 120 from the disk 110 is 3 to 10 mm. The wound arrangement of the inductor 120 around the disk 110 is chosen such that, on supply of the inductor 120 with an alternating voltage, an eddy current is induced in the body of the disk 110. The magnetic field generated by the inductor 120 is substantially oriented in the direction of the disk surface. Due to the Joule's heat produced as a consequence of the induced eddy current, the disk 110 is heated. A liquid containing solid material which is applied on the surface of the disk 110 would thus dry according to the principle of contact drying. The disk 110 further comprises a particular heat capacity determined by the material selected or by the materials composed. The region of the disk 110 which is wound around by the inductor 120 is heated directly inductively by the inductor 120 and thus obtains the necessary operating temperature for drying the liquid containing solid material received on the surface of the disk 110. The remaining region of the disk 110, however, has a lower temperature. It depends on the material and the heat capacity and/or heat conductivity thereof and on the speed of rotation of the disk 110 how the temperature profile is adjusted in the region of the disk 110 which is directly heated inductively and in the region of the disk 110 which is not directly heated inductively.
[0089] FIGS. 4 to 6 show different embodiments of the device package 200 for the industrial drying of a suspension or solution in a front view. In the embodiments the device packages 200 in accordance with the invention consist of four disks 210 which are centrically fastened on a joint bearing shaft and are arranged in parallel to each other. The individual disks 210 are, for instance, formed as in the embodiment of FIGS. 1 to 3. FIG. 4 illustrates an embodiment in which two inductors 220 are assigned to each disk 210. The inductors 220 are moreover arranged such that they are capable of each heating a single disk 210 inductively in the region of one of the side faces thereof. The side faces are positioned along the direction of extension of the disks 210. FIG. 5 illustrates an embodiment in which an inductor 221 is arranged between two disks 210. The inductors 221 heat the side faces of those disks 210 inductively which are arranged adjacently to the inductors 221. The disks 210 which are positioned outside in this device package in accordance with the invention are, moreover, each heated inductively with an inductor 220 at their outer side faces. FIG. 6 illustrates a further embodiment of the device package in accordance with the invention. An inductor 222 is assigned per disk 210. The inductors 222 are such that they heat the disk 210 assigned to them at the opposing side faces along the axis of rotation and/or bearing shaft 230 inductively. The inductors 222 may, for instance, each extend from one side face over the disk edge and to the opposite side face.
[0090] FIGS. 7 to 10 show further embodiments of the device 300, 301, 302, 303 in accordance with the invention in a side view. Different configurations are illustrated for the arrangement of the inductor(s). Depending on the demand on the drying process a plurality of inductors may be distributed along the circumference of the disk 310 for a graded heat introduction into each region of an individual disk 310. In FIG. 7 the inductor 320 is arranged adjacently and at a distance to a side face of the disk 310. Moreover, the inductor 320 comprises an elongated conductor which is wound along the direction of extension of the disk 310 such that the inductor 320 wound along the direction of extension of the disk 310 covers the one side face of the disk 310. Preferably, the inductor 320 comprises two circular portions arranged coaxially about the axis of rotation of the disk 310. The radius of the outer circular portion is preferably about as large as the radius of the disk 310. This embodiment of the invention moreover comprises a removing device 340 and an application device 350. The application device 350 is adapted to apply the liquid containing solid material on the disk 310. The removing device 340, however, is adapted to detach the dry good from the surface of the disk 310, e.g. by a knife resting on the surface. The application device 350 and the removing device 340 are, for instance, arranged adjacently to the disk 310 in that region that is not covered by the inductor 320. In FIGS. 8 and 9 arrangements with a plurality of, e.g. four, individual inductors 321 are shown. If a plurality of individual inductors 321 is used, they may be controlled individually. Both the supply voltage of the inductors and the frequency thereof may be controlled such that individual regions of the disk on which the liquid containing solid material to be dried or else the solid material already dried and having a particular residual moisture is present, experience a graded, varying heat introduction and thus obtain specifically different temperatures. FIG. 8 shows an embodiment of the device 301 in accordance with the invention, wherein the inductors 321 are wound from a respective elongated conductor in a triangle shape along the direction of extension of the disk 310. The inductors 321 are arranged coaxially along the circumference. The inductors 321 may additionally be oriented such that a corner of the triangle-shaped winding of each inductor 321 points to the axis of rotation and/or the bearing shaft. The inductors 321 at one of the side faces of the disk 310 may be within the disk radius or project there above. FIG. 9 illustrates a similar arrangement of the inductors 322 as in the embodiment of FIG. 8. In the embodiment of FIG. 9, the inductors 322 are wound circularly or spirally from an elongated conductor. FIG. 10 shows an embodiment of the device 303 in accordance with the invention in which the inductor 323 is wound from an elongated conductor and comprises a varying winding density along the disk circumference. The winding density may be determined by the distance of adjacent portions of the elongated conductor. A higher winding density means a smaller distance of the adjacent portions of the elongated conductor, and vice versa. The winding density may be of varying intensity by the zone. It may, for instance, be the most intense in the region of the application device and the least intense in the region of the removing device. Such configuration is of advantage since the moisture content of the applied liquid containing solid material is highest directly after applying on the surface of the disk 310 and a large amount of moisture may evaporate. In the region of the removing device the moisture content of the liquid containing solid material is considerably lower, so that a reduced heat introduction in this region of the disk 310 is sufficient to make the residual moisture evaporate. For temperature-sensitive solid materials it may, moreover, be important that they do not exceed a particular temperature so as not to be damaged.
[0091] FIG. 11 shows a schematic view of an embodiment of the system in accordance with the invention. The system illustrated comprises a rotatably mounted disk 310, an inductor 323, a removing device 340, and an application device 350. These components of the system have already been explained in detail before. Furthermore, the system comprises a liquid supply which opens into a liquid tank 370 in which the liquid containing solid material destined to be dried is collected. The application device 350 is connected to the liquid tank 370 to transport and supply the liquid containing solid material from the tank to the surface of the disk 310. Superfluous liquid drips off the disk surface and returns to the liquid tank. Furthermore, the inductor 323 is coupled to a cooling cycle. Coolant is supplied to the inductor 323, which is, for instance, of tubular design, so as to receive the coolant there through. Under normal operating conditions the inductor 323 heats up, the coolant supplied dissipates the heat of the inductor 323 by heat transfer to the coolant. The heated coolant may then be fed into the heat exchanger 360, wherein the liquid supply is pre-heated by the heated coolant as a counterflow before it gets into the liquid tank 370. Thus, heat from the coolant which was withdrawn from the inductor 323 before may be recovered by the pre-heating of the liquid to be dried. The inverter 380 and the oscillating circuit 385 serve for the regulation of the alternating voltage supplied to the inductor 323. Furthermore, the oscillating circuit 385 within the system serves for the power supply of the inductor 323. The exhaust vapor in the form of the moisture evaporated from the liquid to be dried is discharged by means of the extractor 390.
[0092] With the embodiments of the device in accordance with the invention described, it is possible to implement a water evaporative power of approx. 350 kg/h in the drying process. The liquid to be dried is, for instance, a mineral suspension having a solid material content of 50 percent dry substance. The required heating power is provided by the inductive heating with a capacity of 240 kW. The inductors are supplied by a generator with a capacity of 280 kW. By this process a product amount of 437 kg/h with a residual moisture of 10 percent water is produced. The product assumes a temperature of approx. 60° C. due to the drying.
LIST OF REFERENCE SIGNS
[0093] 100, 300, 301, 302, 303 device for industrial drying of a suspension or solution [0094] 110, 210, 310 cylinder/disk [0095] 120, 220, 221, 222, inductor [0096] 320, 321, 322, 323 [0097] 200, 201, 202 device package for industrial drying of a suspension or solution [0098] 230 bearing shaft [0099] 340 removing device [0100] 350 application device [0101] 360 heat exchanger [0102] 370 liquid tank [0103] 380 inverter [0104] 385 oscillating circuit [0105] 390 extractor [0106] 1000 system for industrial drying of a suspension or solution
