WO2006006946A1

WO2006006946A1 - Method for fluid media treatment and induction thereof

Info

Publication number: WO2006006946A1
Application number: PCT/UA2004/000068
Authority: WO
Inventors: Oleksandr Dmitriyevich Podoltsev; Maksim Viktorovich Gachenko
Original assignee: Fos International S.A.
Priority date: 2004-07-09
Filing date: 2004-09-27
Publication date: 2006-01-19
Also published as: RU2342331C2; RU2006133251A; UA75778C2

Abstract

Method for fluid media treatment includes introduction of portion or stream of chemically heterogeneous makeup fluid medium into a tank of an induction heater and heating of this medium under synchronous action of alternating electromagnetic field, heat and mechanical vibrations at frequency that corresponds with frequency variation of said electromagnetic field. This method is realized by the INDUCTION HEATER that has such tank in which at least one electroconductive heating element (4) is placed within heating area with capability for free mechanical vibration under action of alternating electromagnetic field generated by induction winding (12). Under these conditions, covering of heat-exchange surfaces by sediment decreases substantially if even viscous or friable fluid media will be treating.

Description

METHOD FOR FLUID MEDIATREATMENT AND INDUCTION HEATER THEREOF

Field of the Invention

The invention relates to the processes of fluid media treatment and to the structures of induction heaters thereof.

For the purpose of this description, the following terms as employed herein and in the appended claims refer to the following concepts: « Fl u id medium » refers to: first, water obtained from arbitrary natural sources, especially hard waters and/or water contained pathogenic microflora, second, such arbitrary liquid and gaseous media as true solutions and/or emulsions and/or suspensions that are contained dispersed (in particular, mechanical) natural and/or artificial impurities or admixtures, and third, such free-flowing media as corn, arboreal sawdusts or other dispersed vegetable materials, and as sand or other preliminary dispersed minerals;

«Treatment» refers to heating of fluid medium, which is placed within a tank or flows (in particular, passes) through the tank of an induction heater, under synchronous action of alternating electromagnetic field generated by an induction winding, heat and mechanical vibrations at frequency that corresponds (in particular, is multiple) to frequency variation of said electromagnetic field;

^Induction heater» refers to a device equipped with a closed core, at least one induction winding, a tank for placing or passing of processed fluid medium, and at least one a short- circuited electroconductive heating element; this device can operate in periodic mode or, preferably, continuously; «Short-circuited electroconductive heating elemenh refers to each resistance-type- heating element which - is placed within the tank of the induction heater in the action area of alternating electromagnetic field generated by the induction winding, and, when it operates, serves as an electrical conductor for induced eddy currents, and synchronously generates heat and mechanical vibrations under action of said alternating electromagnetic field.

Background Art

It is well known that heating serves as necessary pre-condition of further practical use of many fluid media. The simplest examples are evaporation of water in arbitrary steam boilers and heating of circulating reused water in closed water-heating systems or fresh water in open hot-water supply systems respectively. Also, it is well-known thermal sterilization for suppression of pathogenic microflora in such various fluid media as - drinking water and, especially, water for medical needs, cow's and, seldom, goat's etc. animal milk, usual fluid milk products, and milk-like products based on such vegetable raw materials as soy, nuts etc.

Finally, heating of watery oil or hydrated natural gas before their pumping into trunk pipelines, and drying or other heat treatment of free-flowing materials are required.

All said fluid media contain impurities or admixtures that can form sediments on heat- exchange surfaces.

Sometimes the sediment lowers efficiency of heaters only, but does not worsen (and improves even) quality of the heated product, as it occurs with water after scale formation. However, efficiency of heaters and quality of the heated products decrease usually at the same time. Sterilization or concentration of milk in usual sterilizers or evaporators can serve for examples. In these processes, a part of milk protein coagulates and forms durable sediment on heat-exchange surfaces, and, if operating temperature is too much, food value of protein residue decreases as a result of its thermal denaturation. It is still more difficult to sterilize water that contains resistant to heating microflora, for example, anthrax bacillus spores. In these cases, covering of heat-exchange surfaces by sediment occurs slowly, but solving of problem of reliability and speed of sterilization and minimization of energy intensity takes on special significance.

Unfortunately, engineers were attempted to neutralize either the prerequisites or the consequences of above-mentioned undesirable phenomena only, not interfering in the heating process as such. Only list (no set of abstracts!) of publications dedicated to water demineralization before boiling, removing of scale after water evaporation, and precautions against injury of fluid food products during their thermal sterilization can aggregate several hundred pages. Therefore, thought, that heat treatment of chemically heterogeneous fluid media without perceptible blockade of heat-exchange surfaces by sediments and worsening of treated products quality is possible, was seditious till recently.

«ϋght at the tunnel end» was appeared due to market entry of controlled hydrodynamic cavitation technology. This technology is based on pumping of fluid medium stream through a pipe, at least one part of which is equipped with suitable turbulator as a means of cavitation excitation.

Cavitational bubbles collapse is accompanied by heating of fluid medium and excitation of their mechanical vibrations mainly in audio frequency band. Intensity of these vibrations is sufficed for fine grinding of any hard and/or liquid admixtures to the liquid basis of fluid media and perceptible reduction of covering of cavitational devices walls and pipes by the sediments. Further, the common action of high temperature and intensive mechanical vibrations causes to thermomechanochemical degradation of not only microorganism cells but also arbitrary polymers. For instance, experiments with production and sterilization of soy-bean paste in cavitational devices were allowed to determine that deep thermomechanochemical degradation of vegetable protein and hydrogen sulphide emanation from defective samples of said paste are possible at definite modes of operation.

In other words, synchronous heating and mechanical vibrations can serve as enough universal means for treatment of various fluid media and substantial changes of their physical and/or chemical properties and/or chemical composition. However, cavitational devices are applicable for treatment of such fluid media which are prepared on a liquid basis only and must operate under substantial overpressure in comparison with atmospheric pressure.

For example, WO 98/42987 discloses a cavitational device based on a pipe for pumping of basic stream of processed fluid medium. The pipe wall has at least one through-hole for injection of cavitation exciting stream (as a part of processed or other fluid medium) into said basic stream.

Unfortunately, the cavitation process can be regulated in said devices by pressure changes on inlet of basic stream and/or on inlet of exciting stream in turbulization area only. Therefore, said devices must be used preferably for heating of water (in particular, in water-heating and hot water-supply systems), and preparation, as a rule, binary (for example, oil-water) emulsions or disintegration of turgent seeds of plants. But even such simple processes may provide for effective fluid media treatment (in particular, for speed disintegration of coarse admixture fraction to the fine-dispersed particles) if said cavitational devices are equipped with a contour for processed fluid medium recirculation or with means for cavitation strengthening. First variant increases overall dimensions and mass of the cavitational devices but second variant decreases reliability of theirs.

WO 02/016783 discloses such cavitational device that provides control of concentration of badly condensable gases (usually air) in fluid media and, in that way, control of cavitational bubbles collapse velocity (because this velocity decreases, when concentration of above-mentioned gases in cavitating fluid medium increases). Accordingly, the sets of means for aeration and/or deaeration of fluid medium stream before and/or after cavitation excitation by arbitrary turbulator were disclosed. It is allowed to increase reliability of cavitational devices in above-mentioned field of their application.

It is clear, that synchronous heating and mechanical vibrations of arbitrary processed fluid media in all their volume are very attractive for technologists.

However, capability of the cavitation excitation and, respectively, efficacy of the fluid media thermomechanochemical treatment decreases subsequent to increase of these media viscosity. Further, mechanical vibrations generated by cavitational bubbles collapse are practically beyond regulation neither on amplitude, nor on frequency if even concentration of gases in fluid media will be controlled. Moreover, each cavitational device, when it operates, is source of strong noises and, therefore, must be equipped with a sound insulating cladding that makes difficulties for their technical service and repair. Finally, all such devices are unsuitable for treatment of free-flowing materials and concentrated aerosols in which cavitation is impossible.

Therefore, such means are needed for synchronous thermal and mechanochemical treatment of fluid media that will be relieved from above-mentioned disadvantages.

In the view of inventors, induction heaters must be taken as a base of these means. In fact, their active power may be selected in a wide range according to total volume of processed fluid medium and controlled easily in the range from zero to maximally possible in order to exclude overheating of processed fluid medium. Use of induction heating for fluid media treatment is already known [see, for example:

V.S. Cherednichenko, G.V. Snegireva and K.V. Hatsevskiy «Electro-technological processes of water treatment by induction systems for heating of Iiquids»/Science bulletin of the Novosibirsk State Technical University, 2003 N21(14), Russia; In Russian: B.C. MepeflHuπeHKo, f.B. CHernpeBa M K.B. XaueBCKMM «3jieκτpoτexHoπornHecκκe πpou,ecct>ι o6pa6oτκM BOflbi B MHflyκi4M0HHbix cncTewiax Harpeβa >κnflκocτeκ»/HayHHbiM βecTHMK HOBO- cnδupcKoro rocyflapcTBβHHoro τexHi/mecκoro yHMBepcι/ιτeτa, 2003, Ns1(14), POCCMH].

This memoir discloses, by the example of high-temperature (up to boiling point) heating of hard town water containing 6-7 mg-eq/kg salts, the method and the device that are the most similar to proposed further method and induction heater, namely: (1) method for fluid media treatment including the steps of: a) introduction of portion or stream of chemically heterogeneous fluid medium in induction heater, which comprises of a tank equipped with at least one means for inlet- outlet of fluid medium and with at least one short-circuited electroconductive heating element rigidly fastened within the tank and connected up to at least one induction winding through alternating electromagnetic field, when said heater operates; b) heating of this medium under action of alternating electromagnetic field to the temperature and during time, which are sufficed for achievement of desired results (in particular, to transformation of dissolved salts to fine-dispersed dust which can freely soar in the processed fluid medium), and c) evacuation of treated fluid medium from the induction heater; and

(2) an induction heater for fluid media treatment, the heater includes: (a) a closed core including at least two rods and two connecting yokes;

(b) in particular, at least single-sectional induction winding which surrounds at least one selected core rod and is fed by means of an external alternating current source;

(c) a preferable (but not necessarily) flow-through tank produced from arbitrary (in particular, electroconductive ferromagnetic) material, the tank has: at least one internal wall that surrounds the selected core rod (in particular, together with the induction winding), usually one external wall mounted with a gap respectively to the internal wall, and (in particular, upper and lower) covering end walls which tight block a gap between said internal and external walls, at least one short-circuited electroconductive heating element rigidly fastened within the tank and, when said heater operates, connected with electromagnetic field to at least one induction winding; and at least one means for inlet-outlet of fluid medium. Each known short-circuited electroconductive-heating element is shaped as a ring which is immovable fastened within the tank coaxial to its internal wall. For decreasing of scale formation, each said ring has usually smooth (polished) surface, and their lateral sides are inclined to the horizontal line under an angle which exceeds the angle of mud salt particles friction in a quiet fluid medium.

The described above technology has for principal object the suppression of scale sedimentation on heat-exchange surfaces at heating of hard water only. Such result is explained usually by reference to the experimentally confirmed fact that synchronous action of heat and alternating electromagnetic field transforms dissolved salts, which are determined water hardness, into fine-dispersed meal "soared" in the heated water.

Unfortunately, such electro-thermal process occurs only within such ultrathin layers of fluid medium that are directly adjacent to the heat-exchange surfaces. Thus, blockade of these surfaces by sediments is decreased distinctively then only, when rates of movement of processed fluid medium along them exceed some minimal rate that provokes boiling of said medium liquid basis. It is obvious, that this minimal rate is various for different fluid media and resulting from chemical composition and viscosity of selected fluid medium. It is obvious also, that any excess of the specific minimal rate is accompanied by scale sedimentation on the heat-exchange surfaces if even they are polished and located vertically. Therefore, the known induction heater may be used for treatment of such easy- flowing fluid media as Newtonian liquids, and cannot be used for treatment of such free- flowing (friable) materials as sand, arboreal dusts etc. Brief Description of the Invention

The invention is based on the problem of creation - by change of conditions and means for electro-thermal action on fluid media - such method and such induction heater for fluid media treatment which could provide effective mixing of processed fluid media practically in all their volume and, hence, allow to substantial enhancement of field of induction heaters practical applications. This problem is solved in that in a method for fluid media treatment, including: introduction of portion or stream of a fluid medium in an induction heater, which comprises of a tank equipped with at least one means for inlet-outlet of the fluid medium and at least one short-circuited electroconductive heating element placed within the tank, heating of this medium under action of alternating electromagnetic field generated by induction winding of said heater to a temperature and during a time that are sufficient for achievement of desired results, and evacuation of treated fluid medium, according to the invention the selected fluid medium is introduced into such tank in which at least one said short-circuited electroconductive heating element has capability of free mechanical vibration under action of alternating electromagnetic field, and this fluid medium is heated under synchronous action of alternating electromagnetic field and mechanical vibrations at frequency that corresponds with frequency variation of said electromagnetic field. Intensive mechanical vibration provides for effective mixing of the processed fluid media and, as a result of this mixing, for temperature equalization practically in all tank volume. Therefore, such microlayers of processed fluid medium, that directly adjacent to the all heat-exchange surfaces, are renewed systematically, and danger of local overheating of said medium and covering of said surfaces by sediment decrease substantially. These features allow to use of induction heaters for high-performance treatment of various fluid media, namely: preferably such free-flowing fluid media as weak water solutions of salts or water contained pathogenic bacteria if even induction heater operates in periodic mode; such more viscous fluid media as fruit and/or vegetable juices, milk, syrups and etc. that must be pasteurized or sterilized (preferably at the time of their continuous pumping through the flow- through tank of the induction heater), and such fluid media as free-flowing materials (preferably at the time of their continuous pouring through the flow-through tank of the induction heaters).

Moreover, the proposed method, as it was discovered unexpectedly (and will be shown further), is suitable for rapid and economical sterilization of water infected by such pathogenic microflora that is resistant to prolonged autoclave heating.

The first additional characteristic feature consists in that the treatment is carried out in continuous mode by an induction heater that has a flow-through tank equipped with at least one through-hole for inlet of makeup fluid medium along the heat-exchange surfaces of short-circuited electroconductive heating elements and at least one through-hole for outlet of treated fluid medium. This method is preferable for treatment the fluid media on a liquid basis irrespective of feeding procedure {top-down or bottom-up).

The second additional characteristic feature consists in that the treatment is carried out in continuous mode by an induction heater that has a flow-through tank equipped with at least one upper through-hole for inlet of makeup fluid medium along the heat-exchange surfaces of short-circuited electroconductive heating elements and at least one lower through-hole for outlet of treated fluid medium. This method is preferable for treatment such fluid media as free-flowing (friable) materials.

The problem is also solved in that in an induction heater for fluid media treatment, which comprises of:

(a) a closed core including at least two rods and two connecting yoke; (b) at least single-sectional induction winding which surrounds one selected core rod and is equipped with a means for connection to an alternating current source; (c) a tank, which comprises of: at least one internal wall that surrounds the selected core rod, at least one external wall that is mounted with a gap respectively to said internal wall, and covering end walls which tight block the gap between said internal and external walls, at least one short-circuited electroconductive heating element placed within the tank and, when said heater operates, connected with electromagnetic field to at least one induction winding; and at least one means for inlet of makeup fluid medium and outlet of treated fluid medium, according to the invention at least one short-circuited electroconductive heating element is installed within the tank with capability of free mechanical vibration under action of the alternating electromagnetic field generated by induction winding. This distinguished feature in combination with the known features provides for the advantages that are disclosed higher (after brief description of the method for fluid media treatment according to the invention).

The first additional feature consists in that each said short-circuited electroconductive heating element is shaped as an opened from ends axisymmetric shell. It allows effectively to pass vibration in the all volume of processed fluid medium and hinders to sludging on all heat- exchange area. The second additional feature consists in that at least two said axisymmetric shells are placed with clearance space. It allows to align the mechanical loading in the all volume of processed fluid media if even their viscosity substantially exceeds viscosity of water.

The third additional feature consists in that each said axisymmetric shell is connected with at least one of the tank wall by permeable for a fluid medium resilient supports. Such supports let have to ease of fastening of axisymmetric shells within the tank and practically free mechanical vibrations of theirs under action of the alternating electromagnetic field.

The fourth additional feature consists in that said axisymmetric shells are connected, in turn, to the opposite end walls of the tank. It allows: first, to arrange the axisymmetric shells on a different height, and, second, if the outlet of treated medium is placed near the induction winding, to feed the heater so that fluid medium stream, when it as far as heating, will be advancing to said winding and going into the area of maximal action of the magnetic field.

The fifth additional feature consists in that proper frequency f₀ of vibrations of each pair «axisymmetric shell - resilient support» is fitted the ratio of f_o = (0.5 - 2.0)*2f* where f_c is the working frequency of an alternating current source used for feed of the induction winding. Forced vibrations of short-circuited electroconductive heating elements (i.e., axisymmetric shells) at frequency that is near to their resonance frequency hamper additionally covering of the heat-exchange surfaces by precipitate of such particles which were in fluid media initially or arise out at the time of their treatment.

The sixth additional feature consists in that at least one permeable for processed fluid medium hard support is placed within the tank, and each such support has at least one slot for free placing of end part of at least one said axisymmetric shell. Even if said supports are shaped as hard rings, their slots provide practically free deformation vibrations of the axisymmetric shells. If supports are produced as a few details, they may be easy placed within the tank on equal angular distances in order to minimize hydraulic resistance to the stream of processed fluid medium.

The seventh additional feature consists in that said hard supports and axisymmetric shells installed in said slots of these supports are arranged in at least two tiers, and supports of lower tier are installed on the lower end wall of the tank, whereas supports of each subsequent tier are fastened to the internal or external wall of the tank and placed with an axial gap in respect of the top of the axisymmetric shells of previous tier. It facilitates putting of said shells on vibration resonant mode and increases efficacy of thermomechanochemical fluid media treatment under synchronous action of heat, alternating electromagnetic field and intensive vibrations.

The eighth and ninth additional features, that are related to the second or seventh above-mentioned additional features accordingly, consist in that said axisymmetric shells are produced: either from identical on specific electric resistance material and have different thickness increasing depend upon distance of said shells from the induction winding, or from materials those have different specific electric resistance increasing depend upon distance of said shells from the induction winding.

It allows to align power of eddy currents induced in the axisymmetric shells located on different distances from the induction winding, and, therefore, to align temperature field in the tank volume.

The tenth additional feature consists in that said heater is equipped by additional permanent magnetic field sources selected from the group consisting of - at least one pair of permanent magnets which are fastened near the opposite end walls of the tank and turned by antipole one to other in each pair, and at least two pair of current windings which, in pairs, surround the rods of the closed core near the opposite end walls of the tank and are equipped with means for opposing connection to a continuous current source.

Interaction of alternating eddy currents induced in the axisymmetric shells and the permanent magnetic field: first, substantially multiplies mechanical vibration of said shells and processed fluid medium, second, increases physical and chemical transformations of impurities and/or admixtures, which contain in the processed liquid media, under the action of magnetic field, and third, additionally decreases covering of heat-exchange surfaces by sediment. The eleventh additional feature consists in that said heater comprises of - the closed core composed of three vertical rods, common lower yoke and common upper yoke, three-sectional induction winding, each section of which surrounds one rod of the closed core, and three separate flow-through tanks, each of which surrounds one sections of induction winding and is equipped with at least one such short-circuited electroconductive heating element shaped as an opened from ends axisymmetric shell that surrounds the internal wall of respective tank and proper section of the induction winding.

Such induction heater is intended for connecting to the three-phase network directly or through suitable frequency converter and can be used as high-performance device for simultaneous treatment of identical or different fluid media on liquid basis.

The twelfth additional feature consists in that said heater has: the common lower distributing manifold equipped with three branch tubes for inlet of makeup fluid medium into said tanks, and the common upper collecting manifold equipped with three branch tubes for outlet of treated fluid medium from said tanks.

Such manifolds ease exploitation of induction heater equipped with three separate tanks. The thirteenth additional feature consists in that said heater comprises of - the closed core composed of three vertical rods, common lower yoke and common upper yoke, three-sectional induction winding, each section of which surrounds one rod of said closed core, and one flow-through tank composed of one common external wall, that surrounds all sections of said induction winding, and three separate internal walls, each of which surrounds one section of said winding, and at least three short-circuited electroconductive heating elements, which are shaped as opened from ends axisymmetric shells and installed in at least one tier on permeable for a fluid medium resilient or hard supports co-axially to the proper internal tank walls, and such through-holes for inlet of makeup fluid medium into said tank and outlet of treated fluid medium from said tank, which are shaped in the end tank walls respectively.

It substantially decreases hydraulic resistance to the stream of processed fluid medium and pumping costs.

The fourteenth additional feature consists in that: said heater has two-sectional single-phase induction winding, both sections of which are surrounded one vertical rod of said core with an axial gap, the means for connection of said sections to an alternating current source has one, common for both sections, input, and two, separate for each section, outputs through semiconductor diodes having opposite polarity, the tank is placed in said axial gap between the ends of said sections, internal and external tank walls are equipped with permeable for processed fluid medium supporting hoops which are fastened to said tank walls at least in two tiers and practically parallel to the ends of said sections, short-circuited electroconductive heating elements are shaped as at least two flat rings which are installed in said hoops with capability of free mechanical vibration practically horizontally, and through-holes for inlet of makeup fluid medium and outlet of treated fluid medium are broken through diametrically opposite parts of external tank wall.

Such heater is most suitable for sterilization of water for drink and medical needs. The fifteenth additional feature consists in that said heater comprises of - the closed core having upper and lower horizontal rods and vertically mounted the «left yoke» and «right yoke», the coaxial single-phase induction winding and a horizontal flow-through tank, which surround one horizontal rod of said closed core, at least two flat rings as short-circuited electroconductive heating elements which are located within the tank vertically, and at that through-holes for inlet of makeup fluid medium and outlet of treated fluid medium are broken through diametrically opposite upper and lower parts of external tank wall.

This induction heater is intended for treatment of such fluid media as friable materials.

The sixteenth additional feature consists in that said heater is equipped with such additional sources of magnetic field as at least two permanent magnets which are placed between the external tank wall and the respective horizontal rod of the closed core. Interaction of induced eddy currents and permanent magnetic field multiplies substantially mechanical vibration of said flat rings and, respectively, treated friable material. Therefore, chocking-up of such materials within the tank eliminates practically. The seventeenth additional feature consists in that said heater comprises of - the horizontally located closed core composed of three rods, common «front yoke» and common «back yoke», three-sectional induction winding each section of which is surrounded by one rod of said core, one flow-through tank composed of one common external wall, that surrounds all sections of said winding, and three separate internal walls, each of which surrounds one section of said winding, and three groups of such short-circuited electroconductive heating elements, each of which is shaped as a flat ring, here each group contains at least two said rings which are installed with axial gaps with capability of free mechanical vibration at least in vertical direction and all together surrounded the proper internal wall of said tank, at that through-holes for inlet of makeup fluid medium and outlet of treated fluid medium are broken through diametrically opposite upper and lower parts of external tank wall.

Such heater is equally suitable for treatment of fluid media on a liquid basis (mainly on condition of their bottom-up pumping through the tank) and free-flowing materials (that may be feeding into and evacuating from the tank by gravity top-down).

The eighteenth additional feature consists in that said flat rings belong to middle group are placed partly in axial gaps between said flat rings belong to their extreme groups. This is most expedient for treatment of such fluid media as friable materials. It is clear to each person skilled in art that arbitrary combinations of the basic invention and said additional features are possible. Thus, the described below preferable embodiments don't limit the measure of rights nowise.

Brief description of drawings

The invention will now be explained by detailed description of induction heater and method for fluid media treatment with references to the accompanying drawings, in which: Fig.1 shows schematic longitudinal section of an induction heater that comprises of a single- sectional single-phase induction winding and a vertical tank equipped with short-circuited heating elements that are formed as opened from ends axisymmetric shells and connected to the lower end wall of the tank by resilient supports;

Fig.2 shows schematic longitudinal section of a similar to shown on Fig.1 induction heater equipped with such vertical tank in which the axisymmetric shells are connected in turn to the upper and lower end walls of the tank by resilient supports;

Fig.3 shows schematic longitudinal section of induction heater that comprises of the single- sectional single-phase induction winding and the vertical tank, in which the axisymmetric shells are arranged in one tier to height, surrounded freely one another and leaned on three supports that are installed on the lower end tank wall;

Fig.4 shows the AA transversal section of induction heater showed on Fig.3; Fig.5 shows schematic longitudinal section of similar to shown on Fig.3 induction heater that comprises of the vertical tank, in which the axisymmetric shells are arranged in a few tiers to height, surrounded freely one another in each tier and leaned on the supports installed on the lower end tank wall for the lower tier and on the internal and/or external tank wall for the other tiers;

Fig.6 shows schematic longitudinal section of similar to shown on Fig.3 induction heater equipped with the vertical tank and such axisymmetric shells that have different thickness increasing depend upon their distance from the induction winding;

Fig.7 shows schematic longitudinal section of similar to shown on Fig.3 induction heater equipped with the vertical tank and such additional magnetic field sources as permanent magnets;

Fig.8 shows schematic longitudinal section of similar to shown on Fig.3 induction heater equipped with the vertical tank and such additional magnetic field sources as the additional windings connected to the continuous current source;

Fig.9 shows schematic longitudinal section of three-phase induction heater equipped with three single-sectional induction windings, three separate flow-through vertical tanks and short-circuited heating elements that are formed as opened from ends axisymmetric shells and installed within said tanks on supports;

Fig.10 shows the same, that Fig.9, with additional permanent magnets; Fig.11 shows schematic longitudinal section of three-phase induction heater equipped with a common flow-through vertical tank and such short-circuited heating elements as opened from ends axisymmetric shells that are installed within the tank on hard supports coaxially to the separate induction windings; Fig.12 shows schematic longitudinal section of induction heater equipped with a two-sectional single-phase induction winding, a horizontal flow-through tank, which is placed in the gap between said winding sections, and such horizontal short-circuited electroconductive heating elements that are formed as flat rings and surrounded one of the vertical rods of the closed core; Fig.13 shows schematic electric circuit for connecting of two sections of single-phase induction winding, that is showed on Fig.12, to the alternating current source;

Fig.14 shows schematic longitudinal section of induction heater equipped with a single- sectional single-phase induction winding, a horizontal flow-through tank surrounded the upper rod of the vertical closed core, vertical short-circuited electroconductive heating elements that are formed as flat rings, and such additional magnetic field sources as permanent magnets;

Fig.15 shows three-phase induction heater equipped with a horizontal closed core, a common flow-through tank, and vertical short-circuited electroconductive heating elements that are formed as flat rings;

Fig.16 shows schematic transversal section of the induction heater showed on Fig.15. Best Mode Carrying out the Invention

Any induction heater according to the invention (see drawings, especially the Figs 1 , 3, 5, 9, 12, 14 and 15) contains: a closed core 1 , that is usually produced from laminated electric steel (for operation mainly at industrial frequency 50 or 60 Hz) or from suitable ferrite (for operation at high- frequencies exceeding 1 kHz) and includes at least two rod (not numbered especially) and two connecting yoke (also not numbered especially); at least a single-phase (and multiturn, as a rule) induction winding 2, which is surrounded one selected rod of said core 1 and fed through at least one suitable means for its connecting to an external alternating current source; a tank 3 that may be produced from an electroconductive material (for example, stainless steel), or from such dielectric material as, for example, polycarbonate, teflon or other heat-resistant plastic; the tank 3 has not numbered especially: at least one internal wall which surrounds the selected rod of closed core 1 (usually together with the respective induction winding 2), at least one external wall which is located with a gap relative to the internal wall, covering end walls which tight block a gap between said internal and external walls, and at least two nipple or manifold that are designated on accompanied drawings as « Inlet" of makeup fluid medium into the tank 3 and « Outlet" of treated fluid medium from the tank 3 (it is clear for the person skilled in art, that at least inlet or outlet can be equipped with such suitable locking and regulating element as faucet or valve; these elements are intended to adjusting of fluid medium flow through the tank 3 and/or for locking of the tank 3 for a time sufficed for treatment of adjusted portion of fluid medium); at least one short-circuited heating element 4 produced from suitable electroconductive (magnetic or non-magnetic) material; and at least one support 5 for placing of said elements 4 within the tank 3 with capability of their free mechanical vibration under action of the alternating electromagnetic field generated by the induction winding 3.

Embodiments of induction heater according to the invention can be very various. In the simplest case (see Fig.1), the closed core 1 has two practically vertical rods and two practically horizontal yokes. The single-phase winding 2 surrounds one of said rods tight and is fed by external alternating current source through an arbitrary available connective means. The tank 3 has coaxial preferably cylindrical external and internal walls, at least one inlet and at least one outlet through-holes that are broken in mentioned end walls, and is equipped, as a rule, with a few short-circuited heating elements 4.

Said element 4 can be shaped as an opened from ends axisymmetric (preferable cylindrical) shells. These shells 4 surround coaxially one another with circular gaps and, for providing of capability of their free mechanical vibration, can be connected to at least one of the tank 3 walls by permeable for a fluid medium resilient supports 5.

Said shell elements 4 can be attached with the resilient supports 5 either on the lower end wall of the tank 3 only (Fig.1) or, in turns, to the opposite lower and upper end walls of the tank 3 (Fig.2).

Regardless of attachment of said elements 4 to the tank 3 walls, it is desirable, that proper vibration frequency f₀ of each pair «short-circuited electroconductive heating element 4 as an axisymmetric shell - the resilient support 5» is fitted the ratio of f₀ = (0.5 — 2.0)*2f_c, where f_c is the working frequency of the alternating current source used for feed of said winding 2. Said shell elements 4 can be installed within the tanks 3 on hard supports 5 in one tier (Fig.3) or in a few tiers (Fig.5).

Said hard supports 5 can be shaped as not shown on the drawings rings equipped with at least one radial through-hole (for free flow of processed fluid medium), and with circular slots on their supporting sides (for free placing of said shell elements 4 ends). It is more desirable to make the hard supports 5 as at least two (and, preferable, no less than three) separate ring sectors which have, from the supporting sides, the slots for free placing of the ends of said shell elements 4 (see Figs 3, 4 and 5). It eases flow of processed fluid medium through gaps between the tank 3 walls and/or said elements 4.

It is obvious, that separate ring sectors as hard supports 5 must be installed one from another with practically equal angular distances, and fastened - either to the lower end wall of the tank 3, if said shell elements 4 are arranged in one tier (Fig.3) only, or to the lower end wall of the tank 3 for the lower previous tier, and to the internal or external wall of the tank 3 for each next tier, as it is shown on Fig.5. In this case, second and each following tier of supports 5 must be arranged with an axial gap in respect of the top ends of the shell elements 4 of the respective underlying tier.

If a few shell elements 4 are located coaxially in any tier on different distances from said induction winding 2, they can be produced - from an identical on specific electric resistance material, if thickness of said shells 4 increase depend upon their distance from the induction winding 2, or from different on specific electric resistance materials. In this case, said shells 4 can have practically equal thickness but mentioned specific electric resistance must increase depend upon distance of theirs from the induction winding 2.

It is expedient, if the induction heater is equipped with such additional permanent magnetic field sources as, for example: at least one pair of permanent magnets 6 which are fastened near the opposite end walls of the tank 3 and turned by antipole one to other in each pair (see Fig.7), or at least two pair of current windings 7 which, in pairs, surround the rods of the closed core 1 near the opposite end walls of the tank 3 and are equipped with a means for their opposing connection to an external continuous current source (Fig.8). High-powered (more than 10 kW) induction heater according to invention is equipped preferably with such closed core 1 that have three rods and with three-sectional induction winding 2, each section of which surrounds one rod of said core 1 (Figs 9, 10, 11, 15, 16). All such heaters can be connecting to three-phase industrial network. Some of the substantially different three-phase induction heaters are described below more precisely. So, Fig.9 shows the heater having closed core 1 composed of three vertical rods and common lower and upper yokes. This heater comprises of three separate flow-through vertical tanks 3, and short-circuited heating elements 4 shaped as opened from ends axisymmetric shells which are installed within said tanks 3 on the hard support(s) 5.

Each tank 3 of said heater can be equipped with such additional permanent magnetic field sources as, for example, permanent magnets 6 shown on Fig.10.

If the three-phase induction heater is intended for treatment of the same fluid medium in all separate tanks 3, these tanks 3 can be connected (see Figs 9, 10): to the source of makeup fluid medium - through not numbered especially common distributing manifold equipped with the lower branch tubes, and to the user (or downtank) of treated fluid medium - through also not numbered especially upper collecting manifold equipped with the upper branch tubes. In other embodiments (see Fig.11) the three-phase induction heater can have the common flow-through vertical tank 3 composed of one external wall surrounded all sections of three-phase winding 2, and three internal walls each of which surrounds one section of said winding 2. Through-holes for inlet of makeup fluid medium and outlet of treated fluid medium are broken in opposite end walls of the tank 3. If the number of such through-holes will be more than two from each end tank 3 wall, they must be connected to source of makeup fluid medium and to user of treated fluid medium by respective manifolds. It is obvious, that short-circuited heating elements 4 shaped as opened from ends axisymmetric shells must be installed on resilient or hard supports 5 coaxially to the separate sections of said three-phase winding 2 and the proper internal walls of the common tank 3.

The features of construction of three-phase induction heater for treatment of friable materials, which is shown on Figs 15 and 16, will be considered further.

Now, we will get back to description of some induction heaters for treatment of fluid media on a liquid basis. The special variant of such heater was developed mainly for sterilization of fluid media. This heater (see Fig.12) comprises of: the closed core 1 composed of not numbered especially practically vertical rods and practically horizontal yokes, the two-sectional single-phase induction winding 2, sections 2a and 2b of which together surround one of the rods of said core 1 and are mounted with an axial gap, the practically horizontal flow-through tank 3 placed in said gap between the 2a and

2b sections of said winding 2 and equipped with such through-holes for inlet-outlet of fluid medium that are broken in diametrically opposite parts of the external tank 3 wall, at least two practically horizontal short-circuited electroconductive heating elements 4 that are shaped as flat rings, installed within the tank 3 and surrounded the winding-free part of the rod of said core 1 between the winding sections 2a and 2b, supports 5 which are shaped as permeable for a fluid medium hoops, fastened in pairs to the internal and external tank 3 walls parallel to the opposite ends of said winding sections 2a and 2b, and intended for placing of said flat ring elements 4 with capability of their free mechanical vibration. The means for connecting of said winding sections 2a and 2b to an external alternating current source comprises of one common for both sections input 8 and two separate outputs through semiconductor diodes 9 with opposite polarity (see Fig.13).

It is important that the flat ring elements 4 can be used as heat sources and mechanical vibrators for treatment of free-flowing (friable) materials. Induction heaters for this purpose must be equipped with closed cores 1 having horizontally located rods.

Fig.14 shows a simplest example of such induction heater that comprises of the closed core 1 composed of upper and lower horizontal rods and vertical «left yoke» and «right yoke», the single-sectional single-phase induction winding 2, and the horizontal flow- through tank 3 surrounded one horizontal (in particular, upper) rod of said core 1. Through- holes for inlet-outlet of fluid medium are broken in diametrically opposite upper and lower parts of the external tank 3 wall.

At least two vertical flat rings as short-circuited electroconductive heating elements 4 are installed freely within the tank 3 in a row along the rod of closed core 1. In that case, a cylindrical hub (or preferable, a sector of such hub) equipped with not numbered especially vertical slots is used as the hard support 5. The depth of each said slot exceeds maximally possible amplitude of mechanical vibrations of said elements 4 under action of alternating electromagnetic field generated by the induction winding 2.

For intensification of this field action, the heater can be equipped with such additional magnetic field sources as, preferably, at least two permanent magnets 6. These magnets 6 (see Fig.14) can be located in the gap between the external tank 3 wall and said rod of closed core 1 on conditions that their like poles are unidirectional as a rule. Nevertheless, it is possible such arrangement of permanent magnets 6 as was described above with reference on Fig.7, i.e. by antipole one to other in each pair.

Fig.15 shows one more the three-phase induction heater, which comprises of: the horizontally located closed core 1 composed of three rods, a common «front yoke» and a common «back yoke», such three-sectional induction winding 2, each section of which surrounds one rod of said closed core 1 and, when heater operates, is connected to one of phases of three- phase industrial network, such flow-through tank 3, which comprises of one common external wall surrounded the all sections of induction winding 2 and three separate internal walls, each of which surrounds one section of said winding 2, and three groups of such short-circuited electroconductive heating elements 4, each of which is shaped as a flat ring, here the said ring elements 4 are installed in each group with axial gaps one to other and all together surround the proper internal tank 3 wall, and through-holes for inlet of makeup fluid medium and outlet of treated fluid medium are broken through diametrically opposite upper and lower parts of said external tank 3 wall.

Each said group comprises of at least two said flat ring elements 4. They are installed freely within the tank 3 in a row along the proper rod of closed core 1 on proper support 5.

Each such support 5 is formed as cylindrical hub (or preferable, a sector of such hub) equipped with not numbered especially vertical slots. The depth of each said slot exceeds the maximally possible vibration amplitude of elements 4 under action of alternating electromagnetic field of the proper said winding 2 section. Such hard supports 5 provide of free mechanical vibration of said ring heating elements 4 at least in vertical direction.

It is desirable, that the flat ring short-circuited electroconductive heating elements 4 belong to middle group are placed partly in axial gaps between said elements 4 belong to their extreme groups (see Fig.16). It allows to reduce the overall dimensions of heater.

Processes, that occur inside any tank 3 of any functioning induction heater according to the invention, are the following: each induction winding 2 generates alternating electromagnetic field having such volume electromagnetic power concentration which is determined by general power consumption and useful capacity of the tank 3, further, electromagnetic oscillations excite and deform of electron shells of atoms composing arbitrary processed fluid medium (that causes to changes of physical and chemical properties and reactivity of said medium components), any short-circuited electroconductive heating elements 4 generate of heat (under action of eddy currents) and mechanical vibrations (under action of alternating electromagnetic field) and transfer of theirs into processed fluid medium keeping time with electromagnetic oscillations and intensity depending on active power consumption and viscosity of said fluid medium, and, finally, all these synchronous interchanges of energy and mass exchange (that occur intensively if even tank 3 is produced from dielectric material and equipped with one short-circuited electroconductive heating element 4 only) cause to practically uniform deep thermomechanochemical treatment of fluid medium.

Such magnetic field sources as permanent magnets 6 or current windings 7 provide to the additional (accordingly, passive or active) regulation of said processes.

In general, method for fluid media treatment using arbitrary induction heater according to the invention includes the following steps: 1) conformably to periodic mode:

1.1) introduction of makeup fluid medium portion into the tank 3 to the level not below than upper edge of short-circuited heating elements 4,

1.2) closing of at least lower tank 3 inlet (if treatment provide for drying of sand or arboreal sawdusts and must be conducting on conditions that moisture can evaporate into atmosphere freely) or inlet and outlet of the tank 3 (if treatment provide for sterilization of some fluid media and must be conducting when the tank 3 is isolated from atmosphere),

1.3) treatment of fluid medium portion under said synchronous action of alternating electromagnetic field, heat and mechanical vibration (complemented, optionally, by action of permanent magnetic field) during the time that is sufficed for transformation of dissolved salts to insoluble state, disintegration of hard and/or liquid particles etc. (the physical parameters of this treatment may be determine easily as results of trial experiments),

1.4) evacuation of treated fluid medium from the tank 3 for consumption, or storage, or any further processing;

2) conformably to continuous mode: 2.1) determination (by trial experiments with selected for treatment fluid medium) of such parameters as operating heating temperature, working frequency of induction winding 2 (and, accordingly, mechanical vibration frequency of short-circuited heating elements 4), the consumption of processed fluid medium pumped through the tank 3 and, occasionally, the volume power concentration within the tank 3, and 2.2) pumping of liquid (or pouring of friable) processed fluid medium through the tank 3 under said synchronous action of alternating electromagnetic field, heat and mechanical vibration (complemented, optionally, by action of permanent magnetic field) at experimentally determined parameters for achievement of desired results;

The induction heater was produced for experiments to evaluation of practicability of the invention. This heater, that has efficiency factor 0,93, comprises of: such closed core 1 composed of two vertical rods and two horizontal yokes, that is made from the laminated electric steel E330 a 0,35 mm thick, the single-phase single-section multiturn induction winding 2 by a power 4,6 kW designed for feed from industrial network with maximal current 21 A at cosφ=0,95, the through-flow tank 3 having the useful capacity of 3,0 liter and equipped with six produced from stainless steel coaxial cylindrical shells as short-circuited heating elements 4 that are placed in concentric slots of one hard support 5 on lower end wall of said tank.

Example 1. Treatment of mine water.

Sample of not quite clear rust-colored mine water contained initially 4,6 g/l salts was analyzed chemically. Then 20 / of this water was pumped through the tank 3 of described above induction heater at temperature in the range of 80 to 85⁰C and volumetric flow rate 9 l/min during 10 minutes. The treated water was centrifuged at 6500 revo during 5 minutes for the separation of fine-dispersed mud. Transparent colorless liquid was repeatedly exposed to the chemical analysis. Results are taken in the table 1. Table 1

EFFICIENCY OF MINE WATERS TREATMENT

These data confirm that the method according to the invention can be used for effective high-performance hard water demineralization and, hence, for industrial extraction of many valuable admixtures from non-traditional sources.

Example 2. Treatment of water infected by pathogenic microflora.

The distilled sterile water was inoculated by culture broth contained 5 g/l biomass of the pathogenic microorganism Pseudomonas mendocina P-13. This mix was diluted to concentration 10⁵ cells/ml. Six samples of obtained cell suspension, each of which had volume about 2,5 /, are used, namely: one sample - for check experiment, and five samples - for periodic treatment using the described above induction heater. Conditions of said treatment are indicated in the table 2.

Then all said samples were used for inoculation of such nutrient medium as beef- extract agar. Growth of colonies was controlled on the bright coloring. Results of these experiments are presented in the table 2.

Table 2

EFFICIENCY OF STERILIZATION

These data confirm that the method according to the invention can be used for effective high-performance sterilization of water at very low temperatures and for industrial disinfection of drinking-water and pasteurization or sterilization of fluid food products.

Industrial applicability

Synchronous action of alternating electromagnetic field, heat and mechanical vibration in induction heaters according to the invention provides extraordinarily wide possibilities for thermomechanochemical treatment of arbitrary heterogeneous fluid media for the change of their physical and/or chemical properties and chemical composition.

It is very important, that covering of heat-exchange surfaces by sediment decreases substantially if even viscous or friable fluid media will be treating.

Induction heaters for such treatment may be produced serially at present machine- building plants using available materials.

Claims

C LAI MS

1. A method for fluid media treatment, including: introduction of portion or stream of a fluid medium in an induction heater, which comprises of a tank equipped with at least one means for inlet-outlet of the fluid medium and at least one short-circuited electroconductive heating element placed within the tank, heating of this medium under action of alternating electromagnetic field generated by induction winding of said heater to a temperature and during a time that are sufficient for achievement of desired results, and evacuation of treated fluid medium, - characterized \n that the selected fluid medium is introduced into such tank in which at least one said short-circuited electroconductive heating element has capability of free mechanical vibration under action of alternating electromagnetic field, and this fluid medium is heated under synchronous action of alternating electromagnetic field and mechanical vibrations at frequency that corresponds with frequency variation of said electromagnetic field.

2. The method according to claim 1 characterized in that the treatment is carried out in continuous mode using an induction heater that has a flow-through tank equipped with at least one through-hole for inlet of makeup fluid medium along the heat-exchange surfaces of short-circuited electroconductive heating elements and at least one through- hole for outlet of treated fluid medium.

3. The method according to claim 1 characterized in that the treatment is carried out in continuous mode using an induction heater that has a flow-through tank equipped with at least one upper through-hole for inlet of makeup fluid medium along the heat- exchange surfaces of short-circuited electroconductive heating elements and at least one lower through-hole for outlet of treated fluid medium.

4. An induction heater for fluid media treatment, comprising:

(a) a closed core including at least two rods and two connecting yoke;

(b) at least single-sectional induction winding which surrounds one selected core rod and is equipped wits a means for connection to an alternating current source;

(c) a tank, which comprises of: at least one internal wall that surrounds the selected core rod, at least one external wall that is mounted with a gap respectively to said internal wall, and covering end walls which tight block the gap between said internal and external walls, at least one short-circuited electroconductive heating element placed within the tank and, when said heater operates, connected with electromagnetic field to at least one induction winding; and at least one means for inlet of makeup fluid medium and outlet of treated fluid medium characterized in that at least one short-circuited electroconductive heating element is installed within the tank with capability of free mechanical vibration under action of the alternating electromagnetic field generated by induction winding.

5. The heater according to claim 4 characterized in that each said short-circuited electroconductive heating element is shaped as an opened from ends axisymmetric shell.

6. The heater according to claim 5 characterized in that at least two said axisymmetric shells are placed with clearance space.

7. The heater according to claim 5 or claim 6 characterized in that each said axisymmetric shell is connected with at least one of the tank wall with permeable for a fluid medium resilient supports.

8. The heater according to claim 7 characterized in that said axisymmetric shells are connected, in turn, to the opposite end walls of the tank.

9. The heater according to claim 7 or claim 8 characterized in that proper vibration frequency f₀ of each pair «axisymmetric shell - resilient support» is fitted the ratio of f_o = (0.5 - 2.0)*2f_c where f_c is the working frequency of an alternating current source used for feed of the induction winding.

10. The heater according to claim 5 characterized in that the tank is equipped at least one permeable for processed fluid medium hard support, and each such support has at least one slot for free placing of end part of at least one said axisymmetric shell.

11. The heater according to claim 10 characterized in that said hard supports and axisymmetric shells installed in said slots of these supports are arranged in at least two tiers, and supports of lower tier are installed on the lower end wall of the tank, whereas supports of each subsequent tier are fastened to the internal or external wall of the tank and placed with an axial gap in respect of the top of the axisymmetric shells of previous tier.

12. The heater according to claim 6 or claim 11 characterized in that said axisymmetric shells are produced from identical on specific electric resistance material and have different thickness increasing depend upon distance of said shells from the induction winding.

13. The heater according to claim 6 or claim 11 characterized in that said axisymmetric shells are produced from materials those have different specific electric resistance increasing depend upon distance of said shells from the induction winding.

14. The heater according to claim 4 or to claim 5 characterized in that it is equipped with additional sources of permanent magnetic field selected from group consisting of - at least one pair of permanent magnets which are fastened near the opposite end walls of the tank and turned by antipole one to other in each pair, and at least two pair of current windings which, in pairs, surround the rods of the closed core near the opposite end walls of the tank and are equipped with means for opposing connection to a continuous current source.

15. The heater according to claim 4 characterized in that it comprises of - a closed core composed of three vertical rods, common lower yoke and common upper yoke, a three-sectional induction winding, each section of which surrounds one rod of the closed core, and three separate flow-through tanks, each of which surrounds one sections of induction winding and is equipped with at least one such short-circuited electroconductive heating element shaped as an opened from ends axisymmetric shell that surrounds the internal wall of respective tank and proper section of the induction winding.

16. The heater according to claim Ϊ5 characterized m that it has - a common lower distributing manifold equipped with three branch tubes for inlet of makeup fluid medium into said tanks, and a common upper collecting manifold equipped with three branch tubes for outlet of treated fluid medium from said tanks.

17. The heater according to claim 4 characterized in that it comprises of - a closed core composed of three vertical rods, common lower yoke and common upper yoke, a three-sectional induction winding, each section of which surrounds one rod of the closed core, and one flow-through tank composed of one common external wall, that surrounds all sections of said winding, and three separate internal walls, each of which surrounds one section of said winding, and at least three short-circuited electroconductive heating elements, which are shaped as opened from ends axisymmetric shells and installed in at least one tier on permeable for a fluid medium resilient or hard supports co-axially to the proper internal walls of said tank, and such through-holes for inlet of makeup fluid medium into said tank and outlet of treated fluid medium from said tank, which are shaped in the end tank walls respectively.

18. The heater according to claim 4 ch aracterized in that it has: two-sectional single-phase induction winding, both sections of which are surrounded one vertical rod of said core with an axial gap, the means for connection of said sections to an alternating current source has one, common for both sections, input, and two, separate for each section, outputs through semiconductor diodes having opposite polarity, the tank is placed in said axial gap between the ends of said sections, internal and external tank walls are equipped with permeable for processed fluid medium supporting hoops which are fastened to said tank walls at least in two tiers and practically parallel to the ends of said sections, short-circuited electroconductive heating elements are shaped as at least two flat rings which are installed in said hoops with capability of free mechanical vibration practically horizontally, and through-holes for inlet of makeup fluid medium and outlet of treated fluid medium are broken through diametrically opposite parts of external tank wall.

19. The heater according to claim 4 characterized in that it comprises of - the closed core having upper and lower horizontal rods and vertically mounted the «left yoke» and «right yoke», the coaxial single-phase induction winding and the horizontal flow-through tank, which surround one horizontal rod of said closed core, at least two flat rings as short-circuited electroconductive heating elements which are located within the tank vertically, and at that through-holes for inlet of makeup fluid medium and outlet of treated fluid medium are broken through diametrically opposite upper and lower parts of external tank wall.

20. The heater according to claim 19 characterized in that it is equipped with such additional sources of magnetic field as at least two permanent magnets which are placed between the external tank wall and the respective horizontal rod of the closed core.

21. The heater according to claim 4 characterized in that it comprises of - the horizontally located closed core composed of three rods, common «front yoke» and common «back yoke», the three-sectional induction winding each section of which is surrounded by one rod of said core, one flow-through tank composed of one common external wall, that surrounds all sections of said winding, and three separate internal walls, each of which surrounds one section of said winding, and three groups of such short-circuited electroconductive heating elements, each of which is shaped as a flat ring, here each group contains at least two said rings which are installed with axial gaps with capability of free mechanical vibration at least in vertical direction and all together surrounded the proper internal wall of said tank, at that through-holes for inlet of makeup fluid medium and outlet of treated fluid medium are broken through diametrically opposite upper and lower parts of external tank wall.

22. The heater according to claim 21 characterized in that said flat rings belong to middle group are placed partly in axial gaps between said flat rings belong to their extreme groups.