JPH0622949Y2 - Induction heating device - Google Patents

Description

Detailed Description of the Invention A. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating device that heats a material to be heated with a plurality of heating coils.

B. SUMMARY OF THE INVENTION The present invention sets an outlet temperature of each heating coil in an induction heating device that distributes electric power to each heating coil from the inlet temperature of the first stage of the heating coil and the outlet target temperature of the final stage. By heating the material to be heated by the heating coil of each stage, the difference from the outlet temperature of the previous stage is distributed as a ratio to the difference between the temperature detected at the inlet of the first stage heating coil and the temperature set at the outlet of the final stage. It is something that can be surely done.

C. 2. Description of the Related Art In seam annealer or seam temper equipment in ERW pipe equipment, heating is performed in the forming, welder and sizing equipment. This equipment configuration is the first
This is illustrated in the figure. The material to be heated 1 is conveyed in the direction of the arrow and heated in the heating coils 2 to 4 in the first to third steps, respectively. High-frequency currents are supplied to the heating coils 2-4 from high-frequency power supplies 5-7, respectively. This control of the amount of high-frequency current is distributed by the controller 9 from the final stage target temperature θ _s set in the target temperature setter 8, the inlet temperature θ _{i of the} first stage heating coil 2 and the pipe forming speed S _p . It is given as electric energy E ₁ , E ₂ , E ₃ . The inlet temperature θ _i is detected by the temperature detector 10 and the temperature converter 11, and the pipe forming speed S _p is detected by the speed detector 12 and the speed converter 13.

The distribution of the input electric power to the heating coils 2 to 4 by the control device 9 is obtained by calculating the total required electric power Etotal of the three units from the following equation: Etotal = (θ _s −θ _i ) × W × t × (A · S _p + B) ··· (1) Electric power E ₁ , E ₂ , E ₃ of each heating coil is distributed from the following formula.

In the above equations (1) and (2), W: Seam width of heated material (mm) t: Thickness of heated material (mm) A, B: Determined by outer diameter and thickness of heated material Constant C, D: Constant (≦ 1) D. Problems to be Solved by the Invention In the conventional induction heating device, since the constants C and D are constant, the outlet temperatures of the first and second heating coils 2 and 3 depend on the size of the material 1 to be heated. However, there was a problem that the quality fluctuated and uneven quality occurred.

In order to solve this problem, it is conceivable to detect the outlet temperature of the heating coil of each stage by a detector and control the feed back in each stage, but this leaves a problem that the device becomes complicated.

E. Means and Actions for Solving Problems The present invention has been made in view of the above problems. The inlet temperature θ _i of the first heating coil and the outlet target temperature θ _{s of the} final n-th heating coil are And a means for obtaining the total required electric power Etotal to be supplied to all the heating coils from the constants determined by the material to be heated, the total required electric power and the outlet set temperature θ _n (n
= 1 to n) And a means for setting the electric energy E _n (n = 1 to n) to be distributed to each heating coil in accordance with the above, and the difference between the inlet temperature and the outlet temperature of each heating coil Calculate the power distribution amount from the ratio of

F. Embodiment Hereinafter, an embodiment of the present invention will be described in detail.

In the configuration of FIG. 1, the electric power distribution in the control device 9 is obtained from the following calculation, and the electric powers E ₁ , E ₂ ,
Set E ₃ .

Here, θ ₁ is the outlet temperature of the heating coil 2 of the first stage, θ ₂ is the outlet temperature of the heating coil 3 of the second stage, and these outlet temperatures θ ₁ and θ ₂ are controlled as the target outlet temperature of each stage. The device 9 is preset. Also, the total required power Etotal is the same as the conventional one.
It is calculated from equation (1).

By such power distribution, the outlet temperatures of the heating coils 2 to 4 become θ ₁ and θ ₂ irrespective of the size of the material to be heated ₁ , and the variation in the quality of the seam portion of the material to be heated 1 is eliminated.

FIG. 2 exemplifies the processing flow chart of the control device 9 based on the above-mentioned distribution, and in FIG. 2, it is intended for equipment having n-stage heating coils. The final stage target temperature θ _s is set in the control device 9 (step S1), the detection signal of the inlet temperature θ _i of the first stage heating coil is taken in (step S2), the wall thickness t of the material to be heated and the speed S _{p are set.} The total required electric power Etotal is obtained from the above (step S3). Next, determine the power distribution amount E ₁ to E _n of the heating coil n stages (step S4).
The distribution amounts E _{1 to} En are _expressed by the following equation.

In the above equation, θ ₁ , θ ₂ , ... θ _n-1 are given to the controller 9 as a preset or a data table, and θ _n = θ _s .

(4) power distribution amount E ₁ obtained from expression to E _n is commanded to a high frequency power supply of the heating coils of each stage (step S5), it becomes repetitive control to enter the capture of the next sample data (step S2).

G. As described above, according to the present invention, the total required electric energy is distributed by the ratio of the difference between the inlet temperature and the outlet temperature of each heating coil and the difference between the total inlet temperature and the outlet temperature. The heating temperature by the heating coils of the stages can be made constant irrespective of the size of the material to be heated, and the configuration of the device can be complicated by the setting without detecting the outlet temperature of each heating coil. There is no.

[Brief description of drawings]

FIG. 1 is a block diagram of an induction heating apparatus according to the present invention, and FIG. 2 is a processing flow chart showing an embodiment of the present invention. 1 ... Heated material, 2, 3, 4 ... Heating coil, 5, 6,
7 ... High frequency power supply, 8 ... Target temperature setting device, 9 ... Control device, 10 ... Temperature detector, 11 ... Temperature converter, 12 ... Speed detector, 13 ... Speed converter.

Continuation of the front page (72) Inventor Masayuki Kumigumi 2-1-1-17 Osaki, Shinagawa-ku, Tokyo Inside Stock Company Shameidensha (56) Reference JP-A-55-78490 (JP, A) JP-A-51-87836 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. In an induction heating apparatus for heating a material to be heated by heating coils of a plurality of stages, an inlet temperature θ _i of a first heating coil and an outlet target temperature θ _{s of a} final n-th heating coil. And means for obtaining the total required electric power Etotal to be supplied to all the heating coils from constants determined by the material to be heated, the total required electric power Etotal and the outlet set temperatures θ ₁ , θ of each heating coil.
₂ …, according to the following equation from θ _n Electric energy E _1, E _2, which is distributed to the respective heating coils, ..., induction heating device characterized by comprising a means for setting the E _n.