KR101594572B1 - High frequency inductive heater - Google Patents

Abstract

The present invention relates to a inductive heating roll which comprises: a round inner tube having induction coil wound around the outer peripheral surface thereof; a round outer tube in which the round inner tube is embedded, and of which the outer peripheral surface is heated by electromagnetic induction of the round inner tube; and a controller for providing an induced power of a predetermined frequency to the induction coil. The round inner tube comprises: a core bobbin which is made of a non-magnetic metallic material, and in the form of a cylinder, and of which the inner space is empty as cut in the longitudinal direction of the cylinder to make a gap; a first insulating fabric surrounding the outer peripheral surface of the core bobbin; a core support portion which surrounds the outer peripheral surface of the first insulating fabric, is made of a metallic material and in the form of a cylinder, and has a plurality of insertion grooves in the longitudinal direction of the cylinder, wherein the plurality of insertion grooves are formed at constant intervals along the circumference of the outer peripheral surface; a plurality of permanent magnets which have the same shape as that of the plurality of insertion grooves to be inserted thereinto; a second insulating fabric surrounding the outer peripheral surface of the plurality of permanent magnets and the core support portion; the induction coil wound around the outer peripheral surface of the second insulating fabric; a third insulating fabric surrounding the outer peripheral surface of the induction coil; and a stator which surrounds the outer peripheral surface of the third insulating fabric, is made of a non-magnetic metallic material and in the form of a cylinder, and is cut in the longitudinal direction of the cylinder to make a gap.

Description

{HIGH FREQUENCY INDUCTIVE HEATER}

The present invention relates to a heating roll, and more particularly, to an induction heating roll using a high frequency.

There is a method of controlling the temperature of the roll surface by using oil or water in a heating medium method in a process of producing a film using a heating roll, such as a film stretching process, a glossy process of a fabric or paper.

Further, in a roll using an induction heating system or a ceramic electric heater system, the output control frequency is configured to vary the output control power according to the feedback temperature sensor signal using a commercial frequency.

In the stretching machine of the film process, the smaller the temperature deviation of the roll surface, the more uniform film width and thickness quality can be obtained. In fabric or papermaking process, the less temperature deviation of roll surface, the more flexible and good quality texture and gloss can be obtained. have.

However, conventional induction heating and ceramic heater methods using a commercial frequency output require high power. Therefore, it has a disadvantage of short circuit and it is difficult to reduce the temperature deviation due to the unbalance of the output voltage due to the difference of the input phase voltages.

In addition, ceramic heaters must be replaced with fire and periodic heaters due to the risk of breakage and short life span.

In addition, the heat medium method using oil or water requires disadvantages of leakage and a separate circulation device due to high temperature and pressure, and has disadvantage of performance degradation due to scale, There is a problem that the temperature deviation on the output side becomes large.

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the above-described technical problems, and it is an object of the present invention to provide a permanent magnet capable of controlling temperature by using a plurality of permanent magnets (ferrite core or silicon steel plate) Lt; / RTI >

There is provided an induction heating roll in which permanent magnets (ferrite cores or silicon steel plates) are separated at least in the longitudinal direction of the cylinder and temperature control is carried out by independently supplying induction power to each part.

According to one embodiment of the present invention, there is provided a circular inner cylinder in which an induction coil is wound on an outer circumferential surface; A circular outer cylinder in which the circular inner cylinder is embedded and the outer peripheral face is heated by electromagnetic induction of the circular inner cylinder; And a control unit for providing an induction power of a predetermined frequency to the induction coil, wherein the circular inner cylinder is formed of a non-magnetic metal material having an inner hollow shape and is cut in the longitudinal direction of the cylinder to form a gap Core bobbin; A first insulation pattern surrounding the outer circumferential surface of the core bobbin; A plurality of insertion grooves formed in a cylindrical shape of a metal material and extending in the longitudinal direction of the cylinder, the plurality of insertion grooves being formed at regular intervals along the circumference of the outer circumferential surface, ; A plurality of permanent magnets inserted into the slots with the same shape as the plurality of insertion grooves; A second insulation pattern surrounding the outer circumferential surface of the core support portion and the plurality of permanent magnets; An induction coil wound around an outer circumferential surface of the second insulating cloth; A third insulation foil surrounding the outer circumferential surface of the induction coil; And a stator which surrounds the outer circumferential surface of the third insulating cloth and is formed of a non-magnetic metal material in the form of a cylinder, and has a gap formed in the longitudinal direction of the cylinder to form a gap.

The plurality of permanent magnets may be made of a ferrite core or a magnetic material of a silicon steel sheet, and may have any one of a rectangular parallelepiped, a cylinder, a square column, and a triangular column.

The core bobbin and the stator may be formed of non-magnetic stainless steel, AL, SUS, or carbon.

In addition, the circular outer cylinder is formed of a magnetic metal material, and a copper coating layer is formed on the outer circumference and a chromium coating layer or a ceramic coating layer is formed on the copper coating layer.

The control unit may provide the induction coil with an induction power of a predetermined frequency, and may retrieve and store a plurality of resonance frequencies, and then provide the induction power of any one of the plurality of resonance frequencies .

The control unit may provide the induction coil with an induction power of a predetermined frequency and may provide the induced power of any one of the plurality of resonance frequencies after searching and storing the plurality of resonance frequencies, And the resonance frequency is changed when the fluctuation range of the load current of the induction coil exceeds the reference range from 20 times to 30 times or more.

The plurality of resonance frequencies are automatically changed in a descending order of frequency.

Each of the plurality of permanent magnets is divided into three parts in the longitudinal direction of the cylinder. The control part controls the induction coil to surround both ends of the permanent magnet, and the induction coil to surround the center part of the permanent magnet, To thereby supply the induction power.

The induction heating roll according to the embodiment of the present invention can reduce the temperature deviation by using a plurality of permanent magnets arranged at regular intervals in the longitudinal direction of the cylinder and can prevent the heat generated in the circular inner cylinder from being intrinsically blocked .

Further, it is possible to reduce the temperature deviation of the outer circumferential surface of the circular outer cylinder by separating the permanent magnets into three parts in the longitudinal direction of the cylinder, and supplying independent power to the respective parts (edge, central independent control).

INDUSTRIAL APPLICABILITY The induction heating roll according to an embodiment of the present invention can be applied to a film extruder, a turbine bolt of a power plant, a stretching equipment (fiber, paper, semiconductor), etc., because it can heat the surface uniformly with low power and high efficiency.

1 is a configuration diagram of an induction heating roll according to an embodiment of the present invention;
2 is a circumferential cross-sectional view of the induction heating roll of FIG.
3 is a longitudinal cross-sectional view of the induction heating roll of FIG.
4 is a cross-sectional view of an embodiment of a permanent magnet.
Fig. 5 shows a plurality of resonance frequency bands. Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, in order to facilitate a person skilled in the art to easily carry out the technical idea of the present invention.

FIG. 1 is a configuration diagram of an induction heating roll according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view (A-A ') of the induction heating roll of FIG.

The induction heating roll according to the present embodiment includes only a simple structure for clearly explaining the technical idea to be proposed.

1 and 2, an induction heating roll according to an embodiment of the present invention includes a circular inner cylinder 20, a circular outer cylinder 10, and a control unit (not shown).

The detailed configuration and main operation of the induction heating roll constructed as described above will be described below.

The induction heating roll is configured to be rotated on a rotating shaft in a cylindrical shape, and the surface of the circular outer casing (10) is heated when an induction power of a predetermined frequency is supplied to process the workpiece.

The induction heating roll includes an induction coil 260 for delivering inductive power and a temperature sensor 150 for sensing the surface temperature.

That is, the induction coil 260 is wound around the circular inner cylinder 20, and the surface of the circular outer cylinder 10 is heated by electromagnetic action when induction power of a predetermined frequency is supplied to the induction coil 260.

The induction heating roll is configured to be able to receive electric power through the slip ring 11 and may be provided with a bearing 132 for supporting the rotation. Further, the induction heating roll is configured to be able to rotate around the rotation shaft 130. [ At this time, according to the embodiment, power is directly supplied to the coil wound around the inner tube, and the outer tube is rotated in a fixed state, that is, the outer tube and the inner tube are separated by a bearing. Also, the slip ring may be configured to transmit a temperature sensor signal inserted into the outer cylinder to the outside.

For reference, the detailed configuration of the induction heating roll except for the circular outer cylinder 10, the circular inner cylinder 20 and the control part in this embodiment may be configured differently according to the embodiment.

The induction heating roll includes a circular inner cylinder 20, a circular outer cylinder 10, and a control unit (not shown)

The circular inner cylinder 20 is formed with a structure in which an induction coil is wound on the outer circumferential surface. The detailed structure of the circular inner cylinder 20 will be described later.

The circular outer cylinder 10 has a circular inner cylinder 20 built therein. The outer circumferential face of the circular outer cylinder 10 is heated by electromagnetic induction of the circular inner cylinder 20.

The control unit is configured to provide the induction coil with an induction power of a predetermined frequency. For reference, it is preferable that the control unit is disposed in a portion of the induction heating roll which is susceptible to external power supply and has low heat generation.

FIG. 1 is a configuration diagram of an induction heating roll according to an embodiment of the present invention, FIG. 2 is a cross-sectional view (A-A ') of the induction heating roll of FIG. 1, Direction (B-B ').

The detailed structure of the induction heating roll, particularly the detailed structure of the circular inner cylinder 20 will be described in detail with reference to FIGS. 1 to 3. FIG.

The circular inner cylinder includes a core bobbin 210, a first insulating foil 220, a core support 230, a permanent magnet 240, a second insulating foil 250, an induction coil 260, A third insulating foil 270, an additional induction coil 280, a fourth insulating foil 290, and a stator 310.

The permanent magnet 240 may be composed of a ferrite core or a magnetic substance of a silicon steel sheet. In the present embodiment, it is assumed that the permanent magnet is composed of a ferrite core.

The core bobbin 210 is formed of a non-magnetic, non-ferrous metal material in the form of a hollow cylindrical body. That is, the core bobbin 210 may be formed of a non-magnetic stainless steel material or an aluminum material. The core bobbin 210 is cut in the longitudinal direction of the cylinder to form the cavity 211. For reference, the core bobbin 210 may be formed of non-magnetic stainless steel, AL, SUS, or carbon material.

In the core bobbin 210, the flow of the induction current in the circumferential direction is not generated by the gap 211, so that the internal heat can be cut off from the source. It is preferable that at least one or more voids 211 are formed.

The first insulating foil 220 is configured to surround the outer circumferential surface of the core bobbin 210. The first insulating foil 220 may be configured as a basalt cloth to perform insulation and insulation.

The core supporting portion 230 surrounds the outer circumferential surface of the first insulating foil 220 and is formed of a cylindrical metal material, and may be formed of a non-magnetic stainless steel material or an aluminum material.

The core supporting portion 230 has a plurality of insertion grooves formed in its surface in the longitudinal direction of the cylinder. That is, the plurality of insertion grooves are formed at regular intervals along the circumference of the outer circumferential surface. That is, the insertion grooves are formed at regular intervals in the circumferential direction of the outer peripheral surface.

The plurality of ferrite cores 240 are configured to have the same shape as that of the plurality of insertion grooves, and are inserted and fixed in the respective insertion grooves. For reference, it is preferable that the ferrite core is inserted and fixed after the ceramic adhesive is applied to the surface of the insertion groove.

For reference, non-slip protrusions may be irregularly formed on the surface of the ferrite core 240. The non-slip protrusion may be formed to have a length of 0.1 mm to 1 mm, and the adhesive force may be enhanced by increasing the contact area with the ceramic adhesive applied to the insertion groove of the core support portion 230.

Ferrite cores are ferromagnetic materials with high permeability and low conductivity, which can be used in high frequency circuits. Manganese-zinc ferrite may be used for the low frequency ferrite core of 50 Hz to 20 kHz, and copper-zinc or nickel-zinc ferrite may be used for the high frequency ferrite core of 20 kHz or more. The ferrite core is excellent in heat resistance because it is extruded at 600 to 1300 degrees centigrade.

The ferrite core 240 formed with the above structure has a high magnetic permeability and low eddy current loss in a high frequency band, so that the internal heat generation is reduced. That is, the heat generation of the core bobbin 210 and the stator 310 is reduced by the structure of the ferrite core 240 described above.

In addition, since the plurality of ferrite cores 240 are formed in a structure that is inserted into a plurality of insertion grooves formed in the longitudinal direction of the cylinder, the magnetic field acts in the longitudinal direction of the cylinder and hardly generates vibration due to the magnetic field.

The second insulating foil 250 is configured to surround the outer circumferential surfaces of the core supporting portion 230 and the plurality of ferrite cores 240. The second insulating foil 250 is composed of a basalt cloth, a ceramic cloth, and an asbestos cloth, .

The induction coil 260 is wound on the outer surface of the second insulating foil 250 to perform electromagnetic interaction with the plurality of ferrite cores 240 when inductive power is supplied.

The third insulating foil 270 is configured to surround the outer circumferential surface of the induction coil 260. The third insulating foil 270 may be formed of a basalt cloth to be able to perform an insulation and a thermal insulation function.

At this time, as shown in FIG. 2, in this embodiment, the induction coil may have a multi-wound structure.

That is, the additional induction coil 280 may be wound on the outer circumferential surface of the third insulating foil 270 to perform electromagnetic interaction with the plurality of ferrite cores 240. At this time, the fourth insulating foil 290 is configured to surround the outer circumferential surface of the additional induction coil 280. The fourth insulating foil 290 may be formed of a basalt cloth to perform the insulation and thermal insulation function.

The stator 310 surrounds the outer circumferential surface of the fourth insulating foil 290 and is formed of a cylindrical non-magnetic non-ferrous metal material. That is, the stator 310 may be formed of a nonmagnetic stainless steel material or an aluminum material, and the gap 311 is formed in the longitudinal direction of the cylinder. For reference, the stator 310 may be formed of non-magnetic stainless steel, AL, SUS, or carbon material.

In the stator 310, the flow of the induction current does not occur in the circumferential direction by the gap 311, so that the internal heat can be cut off from the source. It is preferable that at least one or more voids 311 are formed.

On the other hand, in the structure in which the additional induction coil 280 is not provided, the stator 310 may have a structure that surrounds the outer circumferential surface of the third insulating foil 270 and is cut in the longitudinal direction of the cylinder to form the cavity 311 will be. The number of additional induction coils may vary depending on the embodiment, and may be formed by stacking one or more additional induction coils.

4 is a cross-sectional view according to an embodiment of a ferrite core, showing a cross-sectional view of the ferrite core 240 in a circumferential direction.

Referring to FIG. 4, the ferrite core 240 may have any one of a rectangular parallelepiped shape, a cylindrical shape, a rectangular shape, a triangular shape, and an elliptic shape. Since the ferrite core 240 has the same shape as that of the ferrite core 240, the ferrite core 240 is inserted and fixed in the insertion groove.

On the other hand, the circular outer cylinder 10 may be formed of a magnetic metal material, and a copper coating layer may be formed on the outer circumferential surface, and a chromium coating layer or a ceramic coating layer may be further formed on the copper coating layer. The circular outer cylinder 10 is heated so that the workpiece can be formed when the induction coil 260 is supplied with inductive power.

Referring again to Figures 1 to 3,

Each of the plurality of ferrite cores 240 may be formed in a structure that is divided into a plurality of portions in the longitudinal direction of the cylinder.

In this embodiment, the plurality of ferrite cores 240 are formed into three parts (PART1 to PART3) in the longitudinal direction of the cylinder. At this time, the ferrite core 240 according to the embodiment may be formed as a structure separated into at least one part (PART).

When the ferrite core 240 having the structure separated into the three parts PART1 to PART3 and the induction coil 260 perform the electromagnetic interaction like the present embodiment,

The control unit can independently control the heat generation by independently supplying inductive power to the induction coil surrounding the end portions PART1 and PART3 of the ferrite core and the induction coil surrounding the center portion PART2 of the ferrite core. That is, the temperature of the surface of the circular outer cylinder 10 can be uniformly raised by independent supply of the inductive power of the control unit, and local heating is possible.

That is, the induction coil 260 is wound independently of the three parts (PART1 to PART3) of the ferrite core 240, and the control part independently supplies induction power to the independently wound induction coil to enable local heating .

In this embodiment, the same inductive power is simultaneously supplied to both ends PART1 and PART3 of the ferrite core. However, according to the control method, independent induction power is supplied to each portion of the ferrite core, It may be possible. At this time, it is preferable that the temperature sensor 150 is arranged to sense a temperature deviation in the longitudinal direction of the circular outer cylinder 10.

A process of controlling the heat generation by supplying inductive power to the induction coil 260 in the control unit will be described.

The induction coil 260 corresponds to the inductance L and a variable capacitor C connected in series or in parallel with the induction coil 260 may be provided in the control unit. Since the resistance (inductive reactance) of the induction coil 260 is X _L = 2 pi fL and the Joule heat is defined as Q = V ² / Rt [J] = I ² Rt, the lower the resistance value ) Temperature is further increased (i.e., energy efficiency is maximized).

For example, the control unit includes: a blocking unit for blocking an overvoltage and an overcurrent transmitted from an external power supply end; a noise filter unit for blocking noise from an external power supply; an AC-DC converting unit including a constant voltage circuit and a constant current circuit; And an inductive power output unit for converting the power of the AC-DC converter unit into an inducted power of a predetermined frequency and outputting the inducted power.

5 is a diagram showing a plurality of resonance frequency bands.

5, in this embodiment, the control unit provides the induction coil 260 with an induction power of a predetermined frequency. First, a plurality of resonance frequencies are searched and stored, and then a plurality of resonance frequencies F1 to F9 And is configured to provide an inductive power of any one of the resonant frequencies.

Basically, a plurality of resonant frequencies can be automatically changed in a descending order of frequency. That is, when the fluctuation range of the load current of the induction coil 260 is more than 20 times to 30 times or more, the resonance phenomenon occurs when the variation range of the load current of the induction coil 260 is detected in real time And automatically changes from the current resonance frequency to another resonance frequency.

For reference, the control unit can store the resonance frequency when the reference range is exceeded and the change of the surface temperature of the circular outer cylinder 10 for + -1 hour from the point of time when the reference range is exceeded, as the record data.

When the induction heating roll is driven at a later time, the control section can automatically change the resonance frequency when the change in the surface temperature when a specific resonance frequency is used has a similarity degree of 80% or more with the previously stored record data. That is, the control unit can preliminarily change the resonance frequency by referring to the history of the past resonance phenomenon.

In addition, the control unit can adjust the use weight of the resonance frequency exceeding the reference range, that is, the resonance frequency where the resonance phenomenon occurs, and the use weight can be set to be lower by 10% every time the reference range is exceeded.

For example, assuming that there are four resonance frequencies, the initial weight of the first resonance frequency is 25%, the initial weight of the second resonance frequency is 25%, the initial weight of the third resonance frequency is 25% The initial weight of the resonance frequency is 25%.

At this time, when the first resonance frequency exceeds the reference range more than three times, since the weight of the first resonance frequency is -5%, use starts from the second resonance frequency when the induction heating roll is driven at a later time. For reference, when the user resets the resonance frequency, the weight is switched to the initial value.

The induction heating roll according to the embodiment of the present invention can reduce the temperature deviation by using a plurality of ferrite cores arranged at regular intervals in the longitudinal direction of the cylinder and can prevent the heat generated in the circular inner cylinder from being intrinsically blocked .

Further, by separating the ferrite core into three parts in the lengthwise direction of the cylinder and independently supplying inductive power to the respective parts, the temperature deviation of the outer circumferential surface of the circular outer cylinder can be reduced.

Thus, those skilled in the art will appreciate that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

10: circular outer cylinder
20: Circular inner tube
210: core bobbin
211, 311: air gap
220: First insulation foil
230: core support
240: ferrite core
250: Second insulating foil
260: induction coil
270: Third insulating foil
280: additional induction coil
290: Fourth insulating foil
310: stator

Claims (8)

A circular inner cylinder in which an induction coil is wound on an outer circumferential surface;
A circular outer cylinder in which the circular inner cylinder is embedded and the outer peripheral face is heated by electromagnetic induction of the circular inner cylinder; And
And a control unit for providing the induction coil with an induction power of a preset frequency,
In the circular inner cylinder,
A core bobbin made of a non-magnetic metal material having a hollow cylindrical shape and cut in a longitudinal direction of the cylinder to form a gap;
A first insulation pattern surrounding the outer circumferential surface of the core bobbin;
A plurality of insertion grooves formed in a cylindrical shape of a metal material and extending in the longitudinal direction of the cylinder, the plurality of insertion grooves being formed at regular intervals along the circumference of the outer circumferential surface, ;
A plurality of permanent magnets inserted into the slots with the same shape as the plurality of insertion grooves;
A second insulation pattern surrounding the outer circumferential surface of the core support portion and the plurality of permanent magnets;
An induction coil wound around an outer circumferential surface of the second insulating cloth;
A third insulation foil surrounding the outer circumferential surface of the induction coil; And
And a stator which surrounds the outer circumferential surface of the third insulating cloth and is made of a non-magnetic metal material in the form of a cylinder, and is cut in the longitudinal direction of the cylinder to form a gap.
The method according to claim 1,
Wherein the plurality of permanent magnets comprise:
A ferrite core or a magnetic material of a silicon steel sheet,
Wherein the shape of the induction heating roll is one of a rectangular parallelepiped, a cylinder, a square column, and a triangular column.
The method according to claim 1,
Wherein the core bobbin and the stator are made of non-magnetic, non-ferrous material.
The method according to claim 1,
In the circular outer cylinder,
Characterized in that a copper coating layer is formed on the outer circumference and a chromium coating layer or a ceramic coating layer is formed on the copper coating layer.
The method according to claim 1,
Wherein the controller provides the induction coil with an induction power of a predetermined frequency and searches for and stores a plurality of resonance frequencies and then provides the induced power of any one of the plurality of resonance frequencies Induction heating roll.
The method according to claim 1,
Wherein the controller is configured to provide the induction coil with an induction power of a preset frequency and to retrieve and store a plurality of resonance frequencies and then to provide the induced power of any one of the plurality of resonance frequencies,
Wherein the resonance frequency is changed when the fluctuation range of the load current of the induction coil exceeds the reference range from 20 times to 30 times or more.
The method according to claim 6,
Wherein the plurality of resonance frequencies are automatically changed in a descending order of frequency.
The method according to claim 1,
Wherein each of the plurality of permanent magnets comprises:
And is formed as a structure that is divided into three parts in the longitudinal direction of the cylinder,
Wherein the control unit independently supplies induction power to the induction coil surrounding both ends of the permanent magnet and the induction coil surrounding the center of the permanent magnet, respectively.

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