JPH07307194A - Induction heating apparatus - Google Patents

Abstract

PURPOSE:To eliminate temperature unevenness with a lessened number of electric circuits and heighten the electric power consumption efficiency by switching electric circuits for a pair of induction heating coils arranged along a transportation line of conductive materials based on the level of detected temperature. CONSTITUTION:The temperature of a slab F, which moves in x-direction, directly under a temperature sensor is detected by the sensor 6 installed in the upper part of the slab F in the upper stream side and the result is written down in a temperature table of a control circuit 5. Meanwhile, electric application to a pair of electromagnets 1A1, 1A'1 from a coil driver 4a1 is ON/OFF- controlled by the circuit 5 through switches Sa1, Sa'1. The temperature of a space region directly under the electromagnets 1A1, lA'1 is read out by the circuit and comparison is carried out and the electromagnet whose temperature is the lower is electrically communicated through an attached switch. By this skid mark removing method, only a half of the capacity needed conventionally becomes sufficient. The method can be applicable for an apparatus provided with a plurality of pairs of induction heating coils arranged in upper and down stream sides in parallel, a plurality of electric circuits corresponding to the coils, and switching means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating device for making the temperature of a conductive material moving on a transfer line uniform with respect to the moving direction thereof. The present invention relates to an induction heating device for making the temperature of a slab heated in a furnace and conveyed to a rolling mill uniform in the conveying direction. More specifically, the present invention relates to an induction heating device for erasing the skid mark of a slab heated in a heating furnace.

[0002]

2. Description of the Related Art For example, a heating furnace for a slab has a skid for sequentially transferring the slabs charged therein, and the slab in the furnace is supported by a skid rail. Since the inside of the skid rail is cooled with water, the temperature is low, and therefore, the temperature of the portion of the slab extracted from the heating furnace which was in contact with the skid rail is low. That is, low temperature portions called skid marks are distributed at a predetermined pitch in the longitudinal direction of the slab. When the slab is rolled with the skid marks present, uneven rolling may occur in the material and dimensions after rolling at the skid mark portions.

In order to solve this problem, Japanese Patent Laid-Open No. 3-1115
Japanese Patent Laid-Open No. 13-presents a method of heating a low-temperature portion by injecting combustion gas, and also discloses Japanese Patent Laid-Open No. 57-212795, Japanese Patent Laid-Open No. 5-57319, or Japanese Patent Publication No. 61-31946.
The publication discloses an induction heating method. Induction heating
An alternating current is applied to the electric coil to apply an alternating magnetic field to the material to be heated.When the material to be heated is a conductor, an eddy current that circulates an alternating magnetic flux is induced in the material to be heated, resulting in a eddy current jump. The temperature of the material to be heated rises due to the heat of heat.

[0004]

In the above heating method using gas injection, in order to perform uniform heating, it is necessary to constantly apply a certain pressure to the injection gas, that is, to turn on (supply) / inject the injection gas. Since it is difficult to turn off (stop), the parts that do not need to be heated will be heated a little.
There are problems such as low energy use efficiency and low temperature uniformity accuracy. In the induction heating method, the proposal of energizing the roll that conveys the object to be heated (Japanese Patent Application Laid-Open No. 5-57319) can be said to cause the wear of the energized roll to be severe and to have a problem in durability. Further, in the proposal of performing induction heating by using an electromagnet or an induction heating coil in a non-contact manner with an object to be heated (JP-A-57-212795, JP-B-61-31946), the number of electromagnets or induction heating coils is used. Since a power supply complying with the above is always required, when many electromagnets and the like are arranged within one pitch of the skid mark, the equipment tends to be large-scale.

The first object of the present invention is to reduce the temperature unevenness in the carrying direction of the conductor, and the second object is to reduce the number and capacity of the power supply circuits used for the first object. A third purpose is to raise the temperature, and a fourth purpose is to make the temperature distribution of the conductor in the carrying direction finely uniform.

[0006]

An induction heating device according to a second invention of the present application is a pair of induction heating coils for heating a conductive material arranged along a transfer line of the conductive material (F). (1
A1,1A1 '); One power supply circuit (4a1) for supplying induction heating power to the pair of induction heating coils; For selectively connecting each of the pair of induction heating coils to the power supply circuit Switching means (Sa1, Sa1 '); temperature detecting means (6) for detecting the temperature of the conductive material upstream of the pair of induction heating coils with respect to the transport direction of the conductive material; memory for storing the temperature detected by the temperature detecting means. Means (5); and conductive material (F) at the positions (n1, n5) of the pair of induction heating coils (1A1,1A1 ')
The detection temperature (Dn1, Dn5) is obtained from the memory means (5), and the induction heating coil having a conductive material having a high detection temperature is cut off from the power supply circuit via the switching means (Sa1, Sa1 ′). Control means (5) for connecting an induction heating coil having a conductive material having a low detection temperature to the power supply circuit.

An induction heating device according to a fourth invention of the present application comprises a plurality of induction heating coils of a first group for heating a conductive material, which are arranged along a carrying line of the conductive material (F). (1
A1 to 1A4); a plurality of induction heating coils of a second group (1A1 'to 1A1'-) arranged downstream of the induction heating coil of the first group with respect to the carrying direction of the conductive material, for heating the conductive material 1A
4 '); a pair of induction heating coils (1A1,1A1') (1A2,1A2) each consisting of one induction heating coil of the first group and one induction heating coil of the second group ') (1A3,1A3') (1A4,1
A4 ') a plurality of power supply circuits (4a1-4a4) for supplying induction heating power; a plurality of sets for selectively connecting each pair of induction heating coils to each power supply circuit Switching means (Sa1, Sa1 ') (Sa2, Sa2') (Sa3, Sa3 ') (S
a4, Sa4 '); temperature detecting means (6) for detecting the temperature of the conductive material upstream of the induction heating coil of the first group with respect to the transport direction of the conductive material (6); memory means for storing the temperature detected by the temperature detecting means (6) 5); and each pair of induction heating coils (1A1,1A
1 ') (1A2,1A2') (1A3,1A3 ') (1A4,1A4') for each pair of induction heating coils
1, Dn5) (Dn2, Dn6) (Dn3, Dn7) (Dn4, Dn8) are obtained from the memory means and the switching means (Sa1, Sa1 ′) (Sa2, Sa2 ′) (S
a3, Sa3 ') (Sa4, Sa4'), the induction heating coil having a conductive material having a high detection temperature is cut off from the power supply circuit, and the induction heating coil having a conductive material having a low detection temperature is connected to the power supply circuit (4a1).
4a4) to control means (5);

In order to facilitate understanding, the symbols in parentheses that correspond to corresponding elements or corresponding matters in the embodiments shown in the drawings and described later are added for reference.

[0009]

According to the second aspect of the invention, the temperature detecting means (6)
Detects the temperature of the conductive material upstream of the pair of induction heating coils, and the memory means (5) stores the temperature detected by the temperature detecting means. Then, the control means (5), the induction heating coil (1A1, 1A1 ') position (n1, n5) of the conductive material (F) detection temperature (D
n1, Dn5) is obtained from the memory means (5), through the switching means (Sa1, Sa1 '), the induction heating coil having a conductive material having a high detection temperature is cut off from the power supply circuit to obtain a low detection temperature. An induction heating coil with a conductive material is connected to the power circuit.

As described above, since the induction heating power is selectively applied to the induction heating coil in the low temperature portion of the conductive material (F),
Temperature unevenness in the carrying direction of the conductor is reduced. The power circuit is
Since there is one for two induction heating coils, the number of coils can be small. Since the power supply circuit energizes only one of the pair of induction heating coils at a time point, the power capacity may be one coil, and the power capacity allocated to the two coils may be small. Can be used. In this way, not only the required number of power circuits and the required capacity are reduced, but also the control means (5) connects the power circuit to the induction heating coil in the low temperature part of the conductive material to induce induction heating in the high temperature part. Since the coil is cut off from the power supply circuit, induction heating is automatically performed in the required heating portion of the conductive material, and the power consumption effect is high.

According to a fourth aspect of the present invention, there are a plurality of pairs of induction heating coils, one of the pair of induction heating coils belongs to the first group, and the other belongs to the second group. Since the second group is on the upstream side and the second group is on the downstream side, the distance between the pair of induction heating coils in the transport direction is relatively long, and there are a plurality of other pairs of induction heating coils. Exists. The induction heating coils of each pair are selectively connected to the power supply circuits assigned to the induction heating coils of the pair, as in the second aspect of the invention. Therefore, according to the fourth aspect of the invention, in addition to the above-described actions and effects of the second aspect of the invention being obtained in the same manner, the induction heating coils of each pair sequentially heat the low-temperature portions, so that the conductivity is reduced. The temperature distribution in the body transport direction is made uniform in detail.

In the second and fourth inventions, the temperature detecting means (6) detects the temperature of the conductive material upstream of the induction heating coil, and the memory means (5) stores the detected temperature,
Then, the control means (5) reads the detected temperature of the conductive material at each position of the induction heating coil from the memory means (5). This detected temperature is a temperature before passing through the position of the induction heating coil, and when added to the portion heated by the induction heating coil, it does not correctly represent the temperature of the conductive material.

Therefore, the first and third inventions of the present application are provided with temperature detecting means for detecting the temperature of the conductive material at each position of the induction heating coil. According to this, the reliability of the detected temperature of the conductive material at each position of the induction heating coil, which is referred to by the control means (5), is high, and the temperature unevenness in the transport direction of the conductive material can be reduced more accurately. .

Other objects and features of the present invention will be apparent from the following description of each embodiment with reference to the drawings.

[0015]

【Example】

(First Embodiment) FIG. 1 shows the appearance of the induction heating coil portion of the first embodiment. The slab F heated to a predetermined temperature by the heating furnace in the previous stage of the rolling process has its longitudinal direction x (see FIG. 1).
(From left to right), the rollers 7 arranged below the slab F
Is transported by. The top of the slab F, the core 2A of the rectangular body, a first glue wound in a slot cut into the extend in the width direction - up coil 3A ₁ to 3 A ₄ and the second Group - coil 3A of flops the first electromagnet group was equipped with a _{1 '~3A 4' 1
A 1 ~1A 4, 1A 1 '} ~1A 4' is arranged. Also,
At the lower part of the slab F, the electromagnets 1B _{1 to} 1B ₄ , 1B are sandwiched between the rollers 7 supporting the slab F so as to be sandwiched between the rollers.
In parallel is _{1 '~1B 4'} with respect to the rollers 7, also, b to the traveling direction x of the slab F - are arranged alternately with La 7. The electromagnets 1B _{1 to} 1B ₄ and 1B ₁ ′ to 1B ₄ ′ are cores 2B _{1 to} 2B ₄ and 2B ₁ ′ to 2B of a rectangular prism that are long in the width direction.
₄ ', and the coil of the first group wound on the upper surface of the core, that is, the surface facing the slab F, in a slot cut in the longitudinal direction of the core (perpendicular to the traveling direction x of the slab F). 3B _{1 to} 3B ₄ and second group coil 3B ₁ '
~ 3B ₄ '. The electromagnet 1B ₁ ~1B ₄ and 1B ₁ '~1B _4' hereinafter referred to as the second electromagnet group.

FIG. 2 shows an enlarged cross section of the coils 1A ', 1B' and the slab F on the cross section Z indicated by the alternate long and short dash line in FIG. The upper space of the slab F has a gap of 500 mm due to the warp of the slab F. Due to this, there is a space to allow the pole pitch and the iron core shape to be large, and the pole pitch is 1.0e + 3 mm. On the other hand, in the space under the slab F, since the warp of the slab F is practically absent, the gap can be reduced to 40 mm, but since there is a roll (450 mmφ), the pole pitch, iron core shape and current density are reduced. The current density is 0.5 A / m ² .

FIG. 3 shows an overall outline of the first embodiment. In the space above the slab F, regarding the traveling direction of the slab F,
A temperature sensor 6 for detecting the temperature of the slab F is arranged upstream of the first electromagnet group, and the sensor 6 detected by the sensor 6 is arranged.
The temperature (analog signal) of the slab F immediately below is digitally converted and read by the control circuit 5. The control circuit 5 is a computer system having a CPU as a main component.
The temperature data is written in an area for storing the temperature data (hereinafter referred to as a temperature table) in the internal memory or the external memory of the PU.

The roller 7 immediately below the temperature sensor 6 is rotationally driven clockwise by a transport motor (not shown) via a power transmission mechanism (not shown). A pulse generator 8 is connected to the roller 7, generates one pulse of an electric signal for each rotation of the roller 7 by a predetermined small angle, and supplies the electric signal to the control circuit 5.
When one pulse arrives, the CPU of the control circuit 5 executes the "pulse interruption process" shown in FIG. 5, reads the temperature detected by the temperature sensor 6 at that time, and writes it in the temperature table. The content of the "pulse interrupt process" will be described later with reference to FIG.

The energization of the induction in the coil heating power (AC) coil driver 4a ₁ the electromagnets 1A of the first electromagnet group from ~4a _{4 1} ~1A ₄ for providing, 1A _{1 '~1A 4',} the switch Sa _The control circuit 5 performs ON (energization) / OFF (non-energization) control via _{1 to} Sa ₄ and Sa ₁ ′ to Sa ₄ ′. The first pair of coils 1A ₁ and 1A ₁ ′ are selectively connected to the first coil driver 4 via switches Sa ₁ and Sa ₁ ′, respectively.
connected to a ₁ . Switch Sa ₁ of the first pair, Sa ₁ 'is either in accordance with ON / OFF command sent from the control circuit 5 is ON (connected to the coil driver 4a _1), and the other one with OFF (disconnected) Become. That is, the control circuit 5 responds to the ON / OFF command by the first pair of switches S.
a _1, Sa ₁ 'via the first pair of electromagnets 1A _1, 1A _1'
Only one of the electromagnets is energized. Similarly, the second pair of electromagnets 1A ₂ and 1A ₂ ′ are the second pair of switches S.
second coil driver 4a selectively via a ₂ and Sa ₂ '
₂ , the third pair of electromagnets 1A ₃ and 1A ₃ ′ is connected to the third coil driver 4a ₃ via the third pair of switches Sa ₃ and Sa ₃ ′, and the fourth pair of electromagnets 1A ₄ and 1A. ₄ 'the fourth pair of switches Sa _4, Sa _4' is connected to the fourth coil driver 4a ₄ through.

Moreover, energization of the coil driver 4b ₁ ~4b ₄ for providing induction heating power (AC) to the coil to the respective second electromagnet 1B of the electromagnet groups _{1 ~1B 4, 1B 1 '~1B} 4' is ON / OFF control is performed by the control circuit 5 via the switches Sb _{1 to} Sb ₄ and Sb ₁ ′ to Sb ₄ ′. The first pair of coils 1B ₁ and 1B ₁ ′ are switches Sb ₁ and Sb, respectively.
It is selectively connected to the first coil driver 4b ₁ via b ₁ '. The first pair of switches Sb ₁ and Sb ₁ ′ is the control circuit 5
According to the ON / OFF command sent from the other, either one is turned on (connected to the coil driver 4b ₁ ) and the other one is turned off (not connected). That is, the control circuit 5
By the N / OFF command, the first pair of switches Sb ₁ , Sb
Only one of the electromagnets 1B ₁ and 1B ₁ ′ of the first pair is energized via b ₁ ′. Similarly second
The pair of electromagnets 1B ₂ and 1B ₂ 'is the second pair of switches Sb ₂ and
Sb ₂ 'via the selectively connected to a second coil driver 4b _2, third pair of electromagnets 1B _3, 1B _3' third coil driver 4b via a third pair of switches Sb _3, Sb ₃ ' ₃
And the fourth pair of electromagnets 1B ₄ and 1B ₄ ′ are connected to the fourth coil driver 4 via the fourth pair of switches Sb ₄ and Sb ₄ ′.
connected to b ₄ .

FIG. 4 shows the positional relationship between the first and second electromagnet groups and the temperature sensor 6. Illustration of the roller 7 is omitted. Reference numerals n1 to n8 in FIG. 4 represent data representing the distance of each electromagnet from the temperature sensor 6 (the number of pulses counted by the pulse generator 8 shown in FIG. 3).
8 is multiplied by the moving amount of the slab F during one cycle of the pulse generated by the pulse generator 8 to obtain the actual distance.

The electromagnets 1A _{1 to} 1A ₄ , 1 of the first electromagnet group
A ₁ '~1A _4' and the respective second electromagnet 1B of the electromagnet groups _{1 ~1B 4,}
1B ₁ ′ to 1B ₄ ′ are arranged at equal intervals in the traveling direction x of the slab F, and 1A ₁ −1 with the slab F interposed therebetween.
They are oppositely disposed so as _{B 1, 1A 2 -1B 2,} 1A 3 -1B 3 ··· 1A 4 '-1B 4'. Slab F traveling direction x
In the x-direction front-and-back space of the electromagnets in the same electromagnet group, the space area divided by dropping a virtual perpendicular to the slab F from the position corresponding to 1/2 of the x-direction distance between the electromagnets is x. ₁ to x ₈ (x ₁ , x ₂ , ... x ₈
= Constant). Here, a point perpendicular to the slab F from the front end face of the space region x ₈ with the traveling direction x of the slab F as the front intersects with the slab F at a point O, and from the rear end face of the space region x ₁ perpendicular to the slab F. When the point where the line drawn to the slab F intersects the line and the point where the line drawn from the temperature sensor 6 perpendicular to the slab F intersects the slab F is the point Q, the distance PQ is τ ₁ and the distance OP is Be τ ₂ . The electromagnets are arranged so as to be distributed over the entire one pitch τ ₂ of the skid mark of the slab F.

When the slab F travels in the x direction at a speed v,
At a certain instant t _q , the temperature at the point Q of the slab F, which is directly below the temperature sensor 6, measured by the temperature sensor 6 is k _q.
Then, at the instant t _q, the temperature k _{o at} the O point of the slab F and the temperature k _{p at} the P point of the slab F are measured by the temperature sensor 6 at t _q.
Since the temperature k _q at the point Q was already measured at the point Q, the time t _o and t _p at which the respective temperatures k _o and k _p were detected are: time = distance ÷ speed From the relationship of, it is calculated as follows. However, if a number line with t _q = 0 is assumed, then t _q is the present, the + side is the future, and the-side is the past. The calculation method described below also uses the time line as a physical quantity based on the idea of following this number line. It is to be calculated. Further, in this case, since the distance which is a problem is a scalar quantity, an absolute value symbol is attached in the calculation.

(A) Detection time t _o t of the temperature k _o at t _q (t = 0) t _o t _o = t _q − | QO | ÷ v = t _q − (τ ₁ + τ ₂ ) ÷ v = 0 _{- (τ 1 + τ 2)} ÷ v = - (τ 1 + τ 2) / v _{Similarly, (b) t q (t} = 0) detection time of the temperature k _p of the point P in t _p t _p = t _q - | QP | ÷ v = t _q −τ ₁ ÷ v = 0−τ ₁ ÷ v = −τ ₁ / v By the way, the temperature of the slab F at the point Q detected by the temperature sensor 6 depends on the detected time. It is possible to obtain the temperature of each point on the slab F at a certain instant t _q by reading the respective temperatures stored in the memories and corresponding to the time calculated by the above-described calculation method from these memories. However, this is the case where the slab F is not heated by any of the electromagnets. If there is heating by the electromagnet, that portion will naturally
However, in the first embodiment, in order to reduce the number of temperature sensors 6 to be installed, the temperature detected by
Only one temperature sensor 6 is installed, and a temperature table (memory) whose details will be described later is used. This allows the electromagnets to sequentially determine the low temperature portion when the temperature sensor 6 detects the temperature. It will be heated.

Next, referring to FIG. 5, the control device 5 (CP of
The contents of the induction heating control performed by U) will be described. When the pulse generator 8 shown in FIG. 3 generates one pulse, in response to this, the control device 5 executes the "pulse interruption process" shown in FIG. As shown in FIG. 6, address 0 is set in the temperature table.
There is ~ n8. In "Pulse interrupt processing" (Fig. 5), first,
The address of the existing data in the temperature table is shifted in the direction of increasing by one address (S1). That is, address n
The data Dn8-1 of the address n8-1 is written to the address 8, the data Dn8-2 of the address n8-2 is written to the address n8-1, and so on. The data is written, and finally, the data D0 of the address 0 is written in the address 1. As a result, address 0 becomes empty.

Next, the control circuit 5 checks whether or not the temperature detected by the sensor 6 is in the slab temperature range (whether or not the slab F is directly below the sensor 6) (S2).
If YES (YES), the detected temperature data is written to the address 0 of the temperature table (S3), and if NO (NO),
Data Tin representing a predetermined high temperature (no need for heating) is written in address 0 (S4). By repeating such writing of temperature data to the temperature table (repeating execution of "pulse interruption processing" PIN), for example, electromagnet 1A of slab F
The data indicating the temperature of the portion immediately below 1 under the temperature sensor 6 is the address n of the temperature table.
1 will exist. Similarly, data indicating the temperature of the portion immediately below the electromagnet 1A1 'when it was immediately below the temperature sensor 6 exists at the address n5 of the temperature table. The relationship between other electromagnets and the data (slab F) facing the other electromagnets on the temperature table is the same as above.

The control circuit 5 then executes "switching setting 1" S5. That is, from the temperature table, data Dn1 at address n1 (electromagnet 1A1 of slab F)
Of the portion immediately below the temperature sensor 6 and the data D at the address n5.
n5 (data indicating the temperature of the portion of the slab F immediately below the electromagnet 1A1 'when it is immediately below the temperature sensor 6)
Data) to check which is higher (5
1). If Dn1 ≦ Dn5, the switches Sa1 ′, S
b1 ′ is turned off (52) and then the lower temperature Dn1
Is below a threshold value Thn (heating is required) (53), and if it is below the threshold value Thn, the switches Sa1 and Sb1 are turned on (54). As a result, the coil drivers 4a1 and 4b1 are connected to the electromagnets 1A1 and 1B1.
AC power (induction heating power) will be supplied to. D
When n1 exceeds the threshold value Thn (heating is unnecessary), the switches Sa1 and Sb1 are turned off (5
5). This avoids waste burning (unnecessary power input). If Dn1 is higher than Dn5 in the check of step 51, the switches Sa1 and Sb1 are turned off (555), and then the lower temperature Dn5 is set to the threshold value Th.
It is checked whether it is n or less (56), and the threshold value Th
If it is n or less, the switches Sa1 'and Sb1' are turned on (57). As a result, the coil driver 4a
1, 4b1 will supply alternating current electric power to electromagnet 1A1 ', 1B1'. When Dn5 exceeds the threshold value Thn, the switches Sa1 'and Sb1' are turned off (55). This avoids waste burning.

The control circuit 5 then executes "switching setting 2" S6. This content is the same as that of "switching setting 1" S5. However, in the description of the above "switching setting 1" S5, the address n1 is n2 and the data is
Dn1 is connected to Dn2, and switches Sa1, Sb1,
Sa1 'and Sb1' are Sa2, Sb2 and S, respectively.
Electromagnets 1A1 and 1A are read as a2 'and Sb2'.
1 ', 1B1 and 1B1' are 1A2 and 1A respectively
Read as 2 ', 1B2 and 1B2'.

The control circuit 5 then executes "switching setting 3" S7. This content is the same as that of "switching setting 1" S5. However, in the description of the above-mentioned "switching setting 1" S5, the address n1 is n3 and the data is
Dn1 is connected to Dn3, and switches Sa1, Sb1,
Sa1 'and Sb1' are Sa3, Sb3 and S, respectively.
Electromagnets 1A1 and 1A are read as a3 'and Sb3'.
1 ', 1B1 and 1B1' are 1A3, 1A respectively
Read as 3 ', 1B3 and 1B3'.

The control circuit 5 then executes "switching setting 4" S8. This content is the same as that of "switching setting 1" S5. However, in the description of the above-mentioned "switching setting 1" S5, the address n1 is n4 and the data is
Dn1 is connected to Dn4, and switches Sa1, Sb1,
Sa1 'and Sb1' are Sa4, Sb4 and S, respectively.
Electromagnets 1A1 and 1A are read as a4 'and Sb4'.
1 ', 1B1 and 1B1' are 1A4 and 1A respectively
4 ', 1B4 and 1B4'.

The "pulse interrupt processing" PIN described above
When the control signal 5 is executed once, the control circuit 5 waits for the next pulse from the pulse generator 8. When it arrives, the "pulse interruption process" PIN is executed once again.

FIG. 7 shows the temperature detected by the temperature sensor 6 as time passes. In FIG. 7, the cycle To of temperature change (hereinafter referred to as cycle To) is represented by To = because the arrangement of the electromagnets is set so that the distance displacement in the x direction required for one cycle of temperature change is τ _2. τ ₂ ÷ v. That is, when the slab F moves in the x direction at the speed v, the temperature sensor 6 finishes measuring the temperature from the point O to the point P during the period To.

FIG. 8 is a graph showing a state in which the temperature change for one cycle of the slab F (1 pitch of skid mark) is divided by the number of electromagnets (8 in this embodiment) at a certain fixed time interval. It is shown in. The temperature data obtained by the temperature sensor 6 is stored in the temperature table in association with the time section including the measured time by the processing shown in FIG. Then, the control circuit 5 calculates the time at which the temperature of the point O and the point P at a certain instant t _q is measured according to the equations (1) and (2) described above, and searches the time section including the calculated time, This means that the temperatures of the points O and P are specified.

FIG. 9 is a diagram showing the temperature distribution (data distribution on the temperature table) of the slab F at a certain instant t _p according to the length in the x direction. The spatial region x ₁ shown in FIG.
x ₈ is the same as x ₁ ~x ₈ shown in FIG. 4, each electromagnet of a first electromagnet group and a second electromagnet group positioned corresponding to each spatial region below the graph with the electromagnets ON / OFF switch Notated in. Control circuit 5, the temperature Te (the temperature detected by the sensor 6) the temperature of each spatial region x ₂ ~x ₃ from point O of the slab F to致Ru point P - reads from Bull. Referring back to FIG. If FIG. 8 shows the temperature of each point of the slab F (temperature detected by the sensor 6) at the same instant t _{p as} in FIG. 9, the temperature of the x ₁ space region in FIG. At the temperature indicated by Δ8, the temperature in the x ₂ space region in FIG. 9 corresponds to the temperature indicated by Δ1 in FIG. That is, similarly to this, x ₂ −Δ7, x ₃
−Δ6, x ₄ −5Δ, x ₅ −Δ ₄ , x ₆ −Δ 3, x ₇ −Δ 2
The temperature in the corresponding time zone corresponds to the temperature of each space area, and the control circuit 5 reads the respective temperatures from the addresses n1 to n8 of the temperature table to detect the temperature in each space area of the slab F in the x direction (detected by the sensor 6). Temperature). The control circuit 5 then compares the temperatures of the space areas corresponding to the respective electromagnet pairs, and energizes the electromagnets corresponding to the space area having the lower temperature of the electromagnet pair via an attached switch. For example, in FIG. 9, the electromagnet 1A ₁ (1B ₁ )
The electromagnet paired with is 1A ₁ '(1B ₁ '), and comparing the temperatures of the spatial regions x ₁ and x ₅ corresponding to both,
Since k ₁ > k ₅ , the control circuit 5 has an electromagnet of 1A ₁ '(1B
To energize ₁ '), switch Sa ₁ ' (Sb ₁ ') is turned on (marked with a circle in the figure). At this time, the switch Sa ₁ (Sb ₁ ) is off, and the two electromagnets connected in one electromagnet pair are not energized at the same time. Similarly, the control circuit 5 energizes the coil having a low temperature in the corresponding space region for the other electromagnet pairs. In FIG. 9, the electromagnet 1A
₁ '(1B ₁ '), 1A ₄ (1B ₄ ), 1A ₂ '(1
By energizing a total of four electromagnets B ₂ '), 1A ₃ ' (1B ₃ '), the lowest temperature part of the slab F (indicated by the arrow Low in the figure) is sandwiched in the center. The coil will be energized.

FIG. 10 shows that when the instant t _q shown in FIG. 9 is set to t = 0, the time when t _q further advances by 1/4 of one cycle, that is, t = (1/4) × To, The temperature distribution (the temperature detected by the sensor 6) in the space area is shown, and the state of the coil (circled in the figure) energized at that time is shown below the graph. As the slab F progresses, the location Low having the lowest temperature also progresses in the x direction by (1/4) × τ ₂ . Along with that, the control circuit 5 also changes the on / off of the electromagnet, and in FIG. 10, 1A ₂ ′ (1B ₂ ′), 1A ₃ ′ (1
_{B 3 '), 1A 4'} (1B 4 '), are energized 1A ₁ (1B _1).

[0036] Figure 11, the moment t _q a t = 0 and then advanced further by a half period from t _q when the time that is t shown in FIG. 9
= (1/2) × To shows the temperature distribution (temperature detected by the sensor 6) in each space area of the slab F, and the state of the coil (circled in the figure) energized at that time is shown below the graph. ing. Further, in FIG. 12, the instant t _q shown in FIG.
When it is set to 0, the temperature distribution in each spatial region of the slab F (temperature detected by the sensor 6) and the state of energization of the coil in a time period advanced by 3/4 cycle from t _q , that is, t = (3/4) × To Is shown. In Figure 11, Slab F
As the temperature goes down, the location Low with the lowest temperature also becomes (1
/ 2) × τ _{2 is} progressing, and the control circuit 5
Changes the energization of the electromagnet and changes 1A ₄ '(1B ₄ '), 1A ₁
(1B ₁ ), 1A ₂ (1B ₂ ), 1A ₃ (1B ₃ ) are energized. Similarly, in FIG. 12, in the x direction (3/4)
The energization of the electromagnet is changed to 1A ₂ (1B ₂ ), 1A ₃ (1B ₃ ), 1A ₄ (1B ₄ ), 1 according to the Low that is advanced by × τ _2.
I'm going to A ₁ '(1B ₁ ').

The control circuit 5 of the above-described embodiment, in synchronization with the generation of skid marks, energizes only the electromagnet of the two electromagnets paired with each other, which is located in a location where the temperature of the slab F is low. Therefore, compared with the conventional heating system for removing skid marks of the same scale, the required power capacity is half, which leads to downsizing of the heating system and reduction of production cost.

As shown in FIGS. 13 (a) and 13 (b), each electromagnet may be an electric coil that surrounds the slab F and has no core. In this mode, since the slab F penetrates the center of the coil, the thermal efficiency can be improved. Each coil _{1A 1 ~1A 4, 1A 1 '} ~1A 4' switches Sa ₁ -SA ₄ in, Sa ₁ '~Sa _4' are connected. The other structure and operation of each component are the same as those in the above-described first embodiment.

(Second Embodiment) FIG. 14 shows an overall outline of a second embodiment of the present invention. The upper part of the slab F has the same structure as the first electromagnet group in the first embodiment,
The first electromagnet group 1A ₁ in the further downsized second embodiment
˜1A ₄ (first group), 1A ₁ ′ to 1A ₄ ′ (second group) are arranged with the electric coil facing the slab F. Below the slab F, 1.0e of the first embodiment is used.
Rollers 7 having a width wider than +10 ³ to 1.6e + 10 ³ are arranged, and between each roller, the first electromagnet group arranged at the upper part of the slab F has the same structure. Two electromagnet group 1B ₁
˜1B ₄ (first group), 1B ₁ ′ to 1B ₄ ′ (second group) sandwiching the slab F, the electric coil is arranged to face the slab F. Electromagnet 1A ₁ ~ 1A ₄ , 1A ₁ '
To 1A ₄ 'switches Sa ₁ -SA ₄ in, Sa _1' ~Sa ₄ '
However, the switches Sb _{1 to} Sb ₄ and Sb ₁ ′ to Sb ₄ ′ are connected to the electromagnets 1B _{1 to} 1B ₄ , 1B ₁ ′ to 1B ₄ ′, and the operations of the following configurations and elements are described above. Done first
It is similar to the embodiment. In the second embodiment, since the electromagnet is small, the space regions x _{1 to} x ₈ in the x direction of the slab F shown in FIGS. Can be made finer, and the linearity of the temperature distribution after temperature correction is improved. That is, the temperature unevenness is corrected more finely than in the first embodiment.

(Third Embodiment) In the above-described first and second embodiments, one temperature sensor 6 detects the temperature of the conductive material upstream of the induction heating coil 1A1 and the like to detect the temperature.
Write to the bull, and the control means 5 is the induction heating coil 1A.
The temperature detected on the slab F at each position such as 1
Read from Bull. This detected temperature is a temperature before passing through the position of the induction heating coil, and when added to the portion heated by the induction heating coil, it does not correctly represent the temperature of the conductive material.

Therefore, in the third embodiment, as shown in FIG. 15, temperature sensors 6a to 6h are arranged immediately in front of the electric coils 1A1 to 1A4 and 1A1 'to 1A4', respectively, and their detected temperatures are controlled by the control circuit 5. I read it. The other structure and the operation of each component are generally the same as those of the above-described first embodiment, but the control circuit 5 includes S1 to S1 shown in FIG.
Instead of the process of S4, the temperatures detected by the temperature sensors 6a to 6h are read, and these are set to Dn1 to Dn8, and the processes of S1 to S8 are executed. In this third embodiment, the temperature data Dn
Since 1 to Dn8 represent actually measured temperatures, some of those coils are sequentially heated up to Thn (heating necessity or not) even at low temperature places until they enter the electric coils 1A1 to 1A4 and 1A1 'to 1A4'. After the temperature exceeds the judgment threshold value), induction heating is not performed, and the actual low temperature portion is heated instead. Therefore, the temperature distribution in the longitudinal direction of the slab F is made uniform more finely. As the temperature detecting means, for example, there is a method of directly measuring the temperature of the conductive material with a temperature sensor, as shown in the first and second embodiments described above, such as a radiation thermometer, but it is an indirect means. The method of measurement shall be included. That is, for example, when a temperature distribution occurs in the skid rail, the distance between the skid rail, the relative position between the skid rail and the tip of the conductive material, and the reduction ratio (when rolled) of each conductive material conveys. If it is known, the temperature distribution in the carrying direction is indirectly calculated, and it can serve as a temperature component detecting means.

[0042]

EFFECT OF THE INVENTION Two electromagnets form a pair with two electromagnets and share one power source. In synchronization with the generation of the skid mark, the control circuit energizes only the electromagnet located in the place where the temperature of the slab F is low, of the two electromagnets forming a pair. It is possible to drive two electromagnets with one power supply and supply power to only one of them, so when driving electromagnets of the same scale, the capacity of the power supply and the power consumption per unit time compared to the conventional Moreover, the installation space for the power supply is halved, which can reduce the production cost and improve the work space efficiency.

[Brief description of drawings]

FIG. 1 is a perspective view showing the outer appearance of an electromagnet according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a region indicated by alternate long and short dash line Z in FIG.

FIG. 3 is a block diagram showing the overall configuration of the first embodiment.

4 is a side view showing a positional relationship between the electric coil 1A1 and the like shown in FIG. 1 and a slab F. FIG.

5 is a "pulse interruption process" of the control circuit 5 shown in FIG.
It is a flowchart showing the contents of.

6 is a plan view showing the relationship between addresses and write data in a temperature data storage area assigned to a memory in the control circuit 5 shown in FIG.

7 is a time chart showing changes in the temperature detected by the temperature sensor 6 shown in FIG.

8 is a time chart showing changes in the temperature detected by the temperature sensor 6 shown in FIG.

9 is a graph at time t = 0 shown in FIG. 7 and FIG.
The sensor 6 at each position such as the electric coil 1A1 shown in FIG.
It is a graph which shows the slab temperature detected by, ie, temperature distribution.

FIG. 10 is a diagram of FIG. 7 and FIG. 8 from time t = 0 to To
4 is a graph showing a slab temperature detected by a sensor 6, that is, a temperature distribution at each position of the electric coil 1A1 and the like shown in FIG. 3 after / 4 has elapsed.

FIG. 11 is a diagram of FIG. 7 and FIG. 8 from time t = 0 to To
4 is a graph showing a slab temperature detected by a sensor 6, that is, a temperature distribution at each position of the electric coil 1A1 and the like shown in FIG.

12 is a time chart from time t = 0 to 3T shown in FIGS. 7 and 8. FIG.
4 is a graph showing a slab temperature detected by a sensor 6, that is, a temperature distribution at each position of the electric coil 1A1 and the like shown in FIG. 3 after o / 4.

13A and 13B show a modified example of the first embodiment, wherein FIG. 13A is a block diagram showing the overall configuration, and FIG. 13B is a sectional view taken along line YY of FIG. 13A.

FIG. 14 is a block diagram showing an overall configuration of a second embodiment of the present invention.

FIG. 15 is a block diagram showing an overall configuration of a third embodiment of the present invention.

[Explanation of symbols]

_{1A 1 ~1A 4 ', 1B 1} ~1B 4': electromagnets _{2A ', 2B 1 ~2B 4'} : Core _{3A 1 ~3A 4 ', 3B 1} ~3B 4': electrical coils 4a ₁ ~4a ₄ ', 4b _{1 to} 4b ₄ ': coil driver Sa _{1 to} Sa ₄ ', Sb _{1 to} Sb ₄ ': switch 5: control circuit 6: temperature sensor 7: roll 8: pulse generator F: slab

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F27B 9/40 F27D 11/06 Z 7727-4K

Claims (4)

[Claims] 1. A conductive material is arranged along a conveyance line,
A pair of induction heating coils for heating a conductive material;
1 for supplying induction heating power to a pair of induction heating coils
Power supply circuit; switching means for selectively connecting each of the pair of induction heating coils to the power supply circuit; temperature detecting means for detecting the temperature of the conductive material at each position of the induction heating coil And corresponding to the detection temperature of the conductive material at the position of the pair of induction heating coils, the induction heating coil having the conductive material having a high detection temperature is cut off from the power supply circuit via the switching means to detect the low temperature. An induction heating device comprising: a control means for connecting an induction heating coil having a temperature conductive material to the power supply circuit. 2. A pair of induction heating coils for heating the conductive material, arranged along the transfer line of the conductive material (F); for supplying induction heating power to the pair of induction heating coils. One power supply circuit; Switching means for selectively connecting each of the pair of induction heating coils to the power supply circuit; Detecting the temperature of the conductive material upstream of the pair of induction heating coils with respect to the transport direction of the conductive material Temperature detecting means; memory means for storing the temperature detected by the temperature detecting means;
And obtaining the detected temperature of the conductive material at the position of the pair of induction heating coils from the memory means, and disconnecting the induction heating coil having the conductive material having the high detected temperature from the power supply circuit via the switching means. An induction heating device comprising: a control means for connecting an induction heating coil having a conductive material having a low detection temperature to the power supply circuit. 3. Arranged along a transfer line of the conductive material,
A plurality of induction heating coils of a first group for heating the conductive material; a first group of heating elements for heating the conductive material, which are arranged downstream of the induction heating coil of the first group with respect to the transport direction of the conductive material. A plurality of induction heating coils of two groups; one induction heating coil and a second group of the first group, respectively.
A plurality of power supply circuits for supplying induction heating power to a pair of induction heating coils consisting of a single induction heating coil;
A plurality of sets of switching means for respectively selectively connecting each of the pair of induction heating coils to each power supply circuit; at respective positions of the first group and second group of induction heating coils Temperature detecting means for detecting the temperature of a certain conductive material; and, for each pair of induction heating coils, corresponding to the detected temperature of the conductive material at each position of the pair of induction heating coils, via the switching means. An induction heating device comprising: control means for disconnecting an induction heating coil having a conductive material having a high detection temperature from the power supply circuit and connecting an induction heating coil having a conductive material having a low detection temperature to the power supply circuit. 4. Arranged along a conductive material transfer line,
A plurality of induction heating coils of a first group for heating the conductive material; a first group of heating elements for heating the conductive material, which are arranged downstream of the induction heating coil of the first group with respect to the transport direction of the conductive material. A plurality of induction heating coils of two groups; one induction heating coil and a second group of the first group, respectively.
A plurality of power supply circuits for supplying induction heating power to a pair of induction heating coils consisting of a single induction heating coil;
A plurality of sets of switching means, each for selectively connecting each of the pair of induction heating coils to each power supply circuit; a conductive material upstream of the induction heating coil of the first group with respect to the transport direction of the conductive material. Temperature detecting means for detecting temperature; memory means for storing the detected temperature of the temperature detecting means; and for each pair of induction heating coils, the detected temperature of the conductive material at each position of the pair of induction heating coils, And a control means for disconnecting an induction heating coil having a conductive material having a high detection temperature from the power supply circuit and connecting an induction heating coil having a conductive material having a low detection temperature to the power supply circuit via the switching means. Prepare