JPH0751755Y2 - Flat plate heating device - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a flat plate heating apparatus for heating a flat plate-shaped material to be heated by an induction heating coil on the way, and particularly to a flat plate suitable for large capacity. Regarding a heating device.

B. Outline of the Invention The present invention is a flat plate heating apparatus that heats a flat plate-shaped material to be heated by an induction heating coil while moving the same, and a plurality of matching circuits each including an induction heating coil and a capacitor are provided as a matching transformer. By connecting in series to the secondary side, the coil inductance is not limited even with a high-voltage power supply,
It is intended to provide a technique for realizing a large capacity while preventing the movable part, the rotating energizing part, and the cooling device from increasing in size.

C. Conventional Technology A flat plate heating device is a device for heating a flat plate-shaped material to be heated by an induction heating coil while moving it.

FIG. 4 is a block diagram showing an example of a flat plate heating device. In the figure, a flat plate-shaped material to be heated 41 is rewound from the uncoiler 42, moved in the direction of the arrow in the drawing while being guided to the inlet side guide roller 43 and the outlet side guide roller 44, and is disposed midway. While passing through the induction heating coil 45, it is induction-heated to a predetermined temperature. A power source 46 is connected to the induction heating coil 45 and is supplied with alternating electric power for heating.

FIG. 5 is a block diagram of a conventional example of the matching circuit for the alternating power. In the figure, 51 is a material to be heated, 52 is a matching circuit,
53 is a matching transformer and 54 is a power supply. The matching circuit 52 includes a heating coil 55, a rotating energizing section 56 and a capacitor 57, and the heating coil 55 includes an upper heating coil 55a and a lower heating coil 55b.
And is heated by induction when the material 51 to be heated passes between them. The heating coil 55 may be configured to be rotatable in order to make it convenient for maintenance such as coil installation or coil replacement. In this case, the matching transformer 53 is connected to the secondary side via the rotary energizing section 56. The rotating current-carrying unit 56 includes an inner conductor 561 and an outer conductor 562 connected to the matching transformer 53, an inner current collector 563 that rotates and slides with the inner conductor 561, and an outer current collector 564 that rotates and slides with the outer conductor 562. The heating coil 55 is connected via the internal and external collectors 563 and 564 to supply alternating electric power. A matching capacitor 57 is connected in parallel between the matching transformer 53 and the rotation energizing section 56.

D. Problems to be Solved by the Invention In the above-described conventional flat plate heating device, when increasing the capacity such as increasing the heating temperature of the material to be heated or increasing the capacity of the heating device, the inductance of the heating coil is It cannot be changed to a large extent because it is determined to some extent by the capacity of the heating device. Moreover, since the value of the inductance of the heating coil is relatively small, it is difficult to increase the capacitance mainly by the applied voltage. Therefore, without increasing the voltage, the heating coil
Larger capacity can be achieved by increasing the value of the current supplied to 55.

In the circuit configuration shown in FIG. 5, when an attempt is made to increase the capacity, the voltage E is limited by the inductance of the coil, so it is necessary to increase the current to increase the capacity. For example, the capacity is doubled. If desired, the power supply current and the coil current are dealt with as i → 2i and I → 2I, respectively, so that the capacitor current and the coil current increase.

That is, in a large-sized and large-capacity device, a large current is passed through the circuit, so that the coil, bus bar, connection portion, etc. are increased, and accordingly, the entire device is increased in size, resulting in increased waste of cost. In particular, the following three points were major problems associated with the increase in current.

(1) When the coil is heated and a part of the connecting conductor is moved to equalize the plate temperature, the movable part becomes large.

(2) As shown in FIG. 5, when the rotation energizing portion for rotating the coil is provided, the rotation energizing portion becomes large.

(3) Since the high frequency current is used with high density, loss due to a large current is large, water cooling is performed, and the cooling device becomes large.

The present invention was created in view of such problems,
Even high voltage power supply is not limited by coil inductance,
It is an object of the present invention to provide a flat plate induction heating device that realizes a large capacity while preventing the movable part, the rotating energization part, and the cooling device from increasing in size.

E. Means for Solving the Problem The means for solving the above problem in the present invention is to connect a plurality of matching circuits each including an induction heating coil and a capacitor in series to the secondary side of the matching transformer.

Further, the connecting bus bar connecting the matching circuits and the connecting bus bar connecting the capacitors are arranged close to each other so that the current directions are opposite to each other.

F. Action The material to be heated sequentially passes through a plurality of heating coils connected in series and is heated to a high temperature in proportion to the number of passing heating coils. Further, since the heating coils are connected in series, the inductance becomes large in proportion to the number of series coils, and the voltage can be increased accordingly. For example, when using one power source to double the capacity (KVA), the primary current i of the matching transformer may be left unchanged and the voltage may be doubled. Also, since the capacitors are inserted in parallel across the matching circuits, the voltage doubles, but the current is shared by each capacitor 1/2, so the busbars that connect the capacitors are 1/2
A conductor with a current capacity of

In order to reduce the loss in the circuit where a large current flows, if the bus bars of the reverse current are placed close to each other, the reverse currents of the connected bus bars will be equal and the inductance drop due to the high frequency proximity effect will be reduced. . Further, even if a high-voltage power supply is used, it is not limited by the conventional coil inductance, and therefore the same capacity can be secured with a small circuit current.

G. Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, in which two matching circuits including an induction heating coil are connected in series to the secondary side of a matching transformer connected to a power source. In FIG. 1, reference numeral 1 is a material to be heated, 2 and 3 are matching circuits, and the first matching circuit 2 is a heating coil 4, a rotary energizing section 5, a capacitor 6
The second matching circuit 3 includes a heating coil 7 and a rotary energization unit.
8, heating capacitors 4 and 7 are heating coils 4 and 7 of the transverse flux type, each of which is an upper heating coil.
4a, 7a and lower heating coils 4b and 7b. The material to be heated 1 induction-heated between the second heating coils 7a and 7b is passed between the first heating coils 4a and 4b to form two stages. Induction heating. The heating coils 4 and 7 are rotatably arranged in the same manner as in FIG. 5, and the rotary joints 5 and 8 are provided at their connection joints.

The matching capacitors 6 and 9 are installed in parallel between the input side of the first matching circuit 2 and the output side of the second matching circuit 3, and these two connections are connected to the output side of the first matching circuit 2 and A bus bar 10 is usually used for connection between the input sides of the second matching circuit 3.

The input side of the first matching circuit 2 and the output side of the second matching circuit 3 are connected to the secondary side of the matching transformer 11, and the primary side of the matching transformer 11 is connected to the power supply 12. Power supply 12 is 1
In order to obtain a double capacity (KVA) for each unit, the primary current i of the matching transformer 11 can be left unchanged and the voltage can be doubled to 2E. The tank current corresponding to i is the current I in the coil.
Therefore, the current carrying capacity of the rotary energizing parts 5 and 8 and each bus bar need only be sufficient for the current I to flow, and the current carrying capacity of 2I is not required.

The two matching circuits 2 and 3 are all composed of the same type of parts. This is important for streamlining production and equalizing the power burden on each matching circuit.

FIG. 2 is an enlarged sectional perspective view of an example of the arrangement of the bus bar portions 10. In FIG. 2, the connection busbar 20 (current I) between the two matching circuits and the connection busbars 21 (current I / 2) and 22 (current I / 2) between the two matching circuits have a large current flowing in the opposite direction. If busbars with opposite current directions are placed close to each other as shown in the figure, the reverse currents of the connected busbars will be equal and the inductance drop due to the high frequency proximity effect will be reduced, causing abnormal overheating around the busbar. Can be prevented.

FIG. 3 is an explanatory diagram showing an example of a structure in which this embodiment is specifically formed. In the figure (a), 31 is a superheat coil, 32 is a rotary energization part, 33 is a motor part for rotationally driving the heating coil 31, 34 is a matching transformer, 35 is a bus bar, 36
Is a capacitor box, 37 is an insulator, and 38 is a base. FIG. 2B is a side view showing the installation state of the capacitor box 36,
The capacitor box 36 containing the matching capacitors is insulated by an insulator 37 from a base 38 which is a ground plane. This is because the capacitor has two terminals, the top (+) and the ground (-), and the ground side terminal is installed in the capacitor box 36. Therefore, simply mounting the capacitor box on the base 38 As shown in Fig. 1, current flows from the ground side terminal to the top side terminal in the capacitor, so when the base 38 is grounded, the current flowing in the overheating coil also flows to the ground, resulting in power loss. It also causes unfavorable maintenance results. Therefore, an insulator 37 is provided in order to float the capacitor box accommodating the capacitor from the ground.

The following effects are apparent in the embodiment of the present invention.

(1) In a large capacity device, for example, in the case of the configuration shown in FIG.

(2) Regarding the capacitor, the voltage is doubled, but the current is divided into halves, so a busbar or the like may be a circuit with a half current capacity.

(3) In order to reduce the loss in the tank circuit through which a large current flows, if the busbars of the reverse current are placed close to each other as shown in Fig. 2, the reverse currents of the busbars that connect the two will be equal and the high frequency The inductance drop that is likely to occur due to the proximity effect of 1 is small, and abnormal overheating around the bus bar can be prevented.

(4) Since the coil inductance is not limited even with a high voltage power supply, the circuit current is small and the same KVA can be secured.

(5) The voltage of the matching capacitor is doubled, but the current capacity is 1/4, so it is possible to reduce the size and weight, and it is easy to repair and replace.

(6) Only one power supply and one matching transformer (although the unit capacity is large) are sufficient as compared with a system in which a power supply is provided for each matching circuit including a heating coil.

H. Effect of the Invention As described above, according to the present invention, only one power supply and matching transformer is required, a large capacity device can be used with a circuit having half the current capacity of the conventional circuit, and the current capacity of busbars etc. can be half. The matching capacitor has a current capacity of 1/4, which enables downsizing and weight reduction, easy repair and replacement, high voltage power supply does not limit coil inductance, and circuit current is small
It is possible to provide a flat plate heating device that secures the above-mentioned condition, has less inductance drop that tends to occur due to the proximity effect of high frequency, prevents abnormal overheating around the bus bar, and realizes a large capacity.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a partial perspective view of a bus bar of the embodiment, and FIG. 3 is an explanatory view of the structure of the embodiment.
FIG. 4 is a block diagram of a flat plate induction heating device, and FIG. 5 is a block diagram of a conventional example of a matching circuit. 1,51 …… Material to be heated, 2,3,52 …… Matching circuit, 4,7,55 …… Heating coil, 5,8,56 …… Rotating current carrying part, 6,9,57 …… Capacitor, 10 ... Bus Bar, 11,53 ... Matching transformer, 12,54 ...
… Power supply, 20 …… Coupling busbars, 21,22 …… Connecting busbars, 36 …… Capacitor box, 37 …… Insulator.

Claims (2)

[Scope of utility model registration request] 1. A flat plate heating apparatus comprising a plurality of matching circuits each comprising a heating coil and a capacitor connected in series to a secondary side of a matching transformer. 2. The connecting busbar connecting the matching circuits and the connecting busbar connecting the capacitors are arranged close to each other so that the current directions are opposite to each other. Flat plate heating device.