SU1350847A1 - Induction installation for heating ferromagnetic articles - Google Patents

Abstract

The invention relates to electro-f technique. The goal is to improve the accuracy of adjusting the heating mode. The installation contains an inductor 1 connected to the power source 2 through the mode regulator 10. The current and voltage signals of the inductor 1 are fed through the functional converter 8 to the adder 7, which leads to the correction of the signal to the comparison unit 6. Thus, the installation provides automatically taking into account the change in the resistance of the induction system when the supply voltage fluctuates (according to the current of the inductor). 2 Il. SL

Description

The invention relates to electrothermal and can be used in ferromagnetic induction heating.

The purpose of the invention is to improve the accuracy of adjusting the heating mode.

FIG. Figure 1 shows the dependence of the impedance of the induction system upon heating ferromagnetic steel on the temperature of the steel and the value of the field strength generated by the inductor (respectively, on the value of the inductor current); in fig. 2 installation diagram.

When the temperature of the ferromagnetic product is below the Curie point (magnetic conversion point), an increase in the magnetic field intensity (respectively, an increase in the inductor current) leads to a decrease in the resistance of the induction system. This dependence is valid for magnetic field strengths of 1-10 A / m, i.e. at those values of the magnetic field strength that are used in the practice of induction heating.

Based on the experimental studies of the inductor – ferromagnetic loading system, the expression Dependence of the induction system impedance on the product temperature and the inductor current is obtained.

Z K, + K,., - K I

Fri

where Z is the total resistance of the induction system at a given temperature of the product;

T is the temperature of the product; I is the inductor current; K ,, K, coefficients determined by

according to experimental data; p, p - exponents. The coefficients K ,, K, K, and the exponents n, n depend on the intervals of variation of the factors T (product temperature) and I (inductor current) and for each case can be determined experimentally or Theoretically,

Inductor 1 (FIG. 2) is connected to power supply 2 via current sensor 3. The signals from current sensor 3 and inductor voltage sensor 4 are fed to the inputs of dividing unit 5, the output of which is connected to the first input of comparator unit 6. To the second entrance

ten

15

20

25

thirty

35

40

45, 50

.g of the comparison unit 6 receives a signal from the output of the adder 7, the first input of which is connected to the output of the function converter 8 with the power characteristic input-output, and the second input with the setting device 9. The input from the function converter 8 receives the signal from the current sensor 3. A signal from the output of the comparator unit 6 is fed to the input of the mode regulator 10, the output of which is connected to the power source 2.

The installation works as follows.

When voltage is applied from the power source 2 to the inductor 1, a current begins to flow in the circuit of the latter. The signals from current sensor 3 and inductor voltage sensor 4 come in. block

5, the output of which generates a signal proportional to the impedance of the induction system, which is fed to the first input of block 6 of the comparison. The second input of block 6 compares the signal from adder 7, where algebraic summing of the signal from setpoint 9 and the signal from block 8 of the functional converter occurs, the input of which is connected to current sensor 3, Block 6 of comparison, when the signals at its inputs are equal, signals the signal to regulator

10, having the traditional design and implementing control of power supply 2. In the case of a change in the inductor current at a constant product temperature, the signal from the adder 7 connected to the functional converter unit 8 is also connected, which is connected to the current sensor 3 in such a way that the output of the unit

6, the signal is unchanged. For example, when the inductor current decreases, which leads to an increase in the output signal from dividing unit 5, the output signal from dimming unit 8 decreases.

functional converter, which leads to an increase in the signal at the output of the adder 7, and at the output of the comparison unit 6, the magnitude of the signal remains unchanged. Thus, an automatic recording of the change in the resistance of the induction system with fluctuations of the supply voltage level (according to the inductor current) is carried out, and, consequently, the accuracy of controlling the heating mode of ferromagnetic products is improved.

When using the device, its technical and economic efficiency is determined by increasing the accuracy of controlling the heating mode of ferromagnetic products, which increases the heating quality of the product and reduces the energy intensity of the process.

Claims (1)

Invention Formula An induction unit for heating ferromagnetic products containing an inductor connected to the output of a power source, the control input of which is connected to the output of a mode regulator, to the input of which is connected the output of the comparator unit connected by the first input to the output of the division unit to the inputs of which are connected. inductor current sensors and voltages on it, and a mode setter, characterized in that, in order to increase the accuracy of heating mode control, an adder and a functional converter with an input-output power characteristic, whose input is connected to the current sensor output, are entered into the installation, and the output is to the first input of the adder connected by the second input to the output of the setter, and the output to the second input of the block | Editor N. Dumbass Compiled by Oh, Turpak Tehred M. Morgenthal Order 5300/58 Edition 799 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d, 4/5 Production and printing company, Uzhgorod, st. Project, 4 FIG. GK Proofreader A. T sko