SU1178782A1 - Device for controlling the heating of ferromagnetic blanks in continuous heating unit - Google Patents

Abstract

one; A device for controlling the heating of ferromagnetic blanks in a methodical heating device, containing a controlled power supply connected to the heater, the control input of which is connected to the controller output, two inductive sensors located outside of the heater along its longitudinal axis, the bend curved bending frame, that the bend is turned by the bend of the bend, that the bend is turned by the bend of the controller, that the bend is turned by the bend of the regulator, that is, the bend of the controller, the bend of the controller, the bend of the controller, the bend of the controller, the bend of the controller, the bend of the controller, that the bend of the controller, that the bend of the regulator is turned, the bend of the controller of the controller, that the bend of the control of the bend’s connected to the output of the comparison unit, to the inputs of which the output of the movement mechanism of the inductive sensors is connected, the speed sensor ne emescheni workpiece, characterized in that, in order povpieni performance and accuracy to maintain a predetermined temperature of the metal in the transition. heater start up modes, it is equipped with a control unit, a switching unit and four keys, with the first and second inputs of the switching unit connected to the outputs of the speed sensor and the controller, and the output to control inputs of all keys, the first of which is located between the speed sensor and the input the comparator unit, the second by the output of the inductive sensors and the controller input, the third by the output of the inductive sensors and the input of the comparison unit, and the fourth by the controller input and the output of the control unit, one of the inputs of which is connected to the output of the regulator, and the second - with the output of the actuator displacement actuator :: s. 2. A device according to Claim 1, characterized in that the control unit contains a key, a comparator, an analog storage unit, two amplifiers, the output of one of which is connected to the analog input (L C of the memory unit via a switch, the first control input of which connected to the comparator output, to one of the inputs of which the output of the other amplifier is connected, the first input of the control unit is the second input of the comparator, the second input is the inputs of the amplifiers, and the output of the analog storage unit. that block comm The ution contains a memory unit, a reference voltage source and a comparison unit, the reference voltage source being connected to the first input of the comparison unit, the output of which is connected to the first input of the memory unit, the second input of which is the first input of the switching unit, the second input of the comparison unit is the second input of the switching unit; the output of the memory unit is the output of the switching unit.

Description

1 11

The invention relates to electrothermal and can be used in metallurgical, engineering and other industrial areas using heating installations of non-continuous action, such as induction, for heating ferromagnetic blanks to temperatures exceeding the temperature of magnetic transformations.

The purpose of the invention is to improve the performance and accuracy of maintaining the desired metal temperature in transient start-up modes of the heater.

FIG. 1 shows a functional diagram of the device; Fig. 2 shows a graph of the change in power and temperature at the exit from the heater; in fig. 3 - temperature distribution along the heater; in fig. 4 is a plot of the change in heating power as a function of the coordinates of the magnetic transformation point.

The device contains a heater 1, inductive sensors 2 and 3, a regulator 4, made, for example, on the basis of an RBA-P regulating device of the AKESR system, an adjustable power supply 5, for example ARIR, a heated product 6, a metal displacement sensor 7, block 8 comparisons made, for example, on the basis of the summation unit type BKR-1-P of the AKESR system, the actuator 9 for moving inductive sensors, the control signal generating unit 10, the switching unit 11, the keys 12-15.

The control signal conditioning unit 10 comprises amplifiers 16,17, ompator 18, key 19, analog memory lock 20, effectively, for example, based on the BESP-P dynamic transform unit of the KESR system.

Switching unit 11 contains a 21 am unit, made, for example, on the basis of the dynamic conversion unit BDP-P of the AKESR system, reference source 22, comparison unit 23, fulfilled, for example, on the basis of the БСЛ-04 block of the AKESR system.

In the process of starting the heater from a cold state, when there are cold blanks in the heater, when the mechanism for moving the blanks is turned on, the start signal acts

822

to block 21 of memory of switching unit II. At the output of the memory block 21, a signal corresponding to 1 appears, which affects the keys 12-15, disconnects using the key 12 the input of the comparison unit 8 from the output of the speed sensor 7 and connects the second input of the comparison unit 8 to the output of the inductive sensors 2 and 3 with a key

14. At the same time, the key 13 disconnects one input of the controller 4 from the output of the inductive sensors 2 and 3, and the key 15 connects the second input of the controller 4 to the logic block 10 of the formation

control signal.

Since there are cold billets in the inductor, inductive sensors 2 and 3 generate a signal that, via key 14 and comparison unit 8, acts on actuator 9 of movement of inductive sensors, which moves inductive sensors 2 and 3 to the right. When inductive sensors 2 and 3 are moved to the position corresponding to the coordinate of the Curie point in setting the mode of operation at minimum speed, the signal from the output of the actuator 9 is affected

key 19, connect the input of memory block 20 to the output of amplifier 17. Analog memory block 20 generates a signal which, via key 15 and regulator 4, acts on adjustable source 5 of power by connecting maximum power to heater 1.

. Under the action of the power supplied to the heater, the temperature distribution in the metal varies along the length of the heater, and the coordinate of the magnetic transformation point moves to the left (Fig. 3), causing a change in the signal at the output of sensors 2 and 3.

The error signal at the output of in-. dual sensors 2 and 3 through the key 14 and the comparison block 8 acts on the actuator 9, which moves the inductive sensors

in the direction corresponding to the elimination of mismatch.

The signal from the code of the actuator 9 for moving inductive sensors 2 and 3 acts on the amplifiers 16, 17 of the control signal generating unit 10. From the output of the amplifier 16, the signal is fed to one input of the comparator 18; The other input of the comparator 18 receives a signal from the output of the regulator 4. At the moment of equality of these signals, the comparator generates a siptal at the output that acts on the switch 19, connects the output of the amplifier 17 to the input of the analog memory block 20. The analog memory unit 20, when the key 19 is closed, generates a control signal acting through the switch 15 on the controller 4. The controller 4 acts on the regulated power supply 5 by changing the input power level to a value corresponding to the condition of maintaining the metal temperature at the heater output on a given. The required power level is determined from the ratio P kU, where the U signal at the amplifier output 17 is 17 when the signals from the output of the amplifier 16 and from the output of the regulator 4 are matched, and the key 19 connects the input of the memory block 20 to the output of the amplifier 17; k is a factor proportional to tee between power and voltage at the output of amplifier 17 (DE line in FIG. 4). Under the action of the new power level, the coordinate of the Curie point will begin to move to the right (FIG. 1,3); the error signal at the output of the inductive sensors 2 and 3 through the key 14 and the comparison unit 8 acts on the actuator 9, moving the inductive sensors 2 and 3 in the direction of reducing the error when the signals from the output of the amplifier 16 and the output of the regulator 4 at the input of the compressor 18 again compare The comparato generates a signal at the output, which acts on the key 19, connecting the signal from the amplifier 17 to the input of the memory block 20. The signal is again formed, which through the switch 15 and the controller 4 acts on the controlled power supply 5, changing the level of the power supplied to the heater. Such a process of a stepwise change in the heating power will be -50 until the power level becomes equal to the steady-state value. At the moment of equality of the power supplied to the heater, the set value, the signal at the 55th input of the comparison unit 23 becomes equal to the reference-signal; Comparison unit 23 generates a signal that acts on the second input of the 2T memory unit. At the output of memory block 21, a signal corresponding to O appears, which affects the keys 12-15, connects one key 12, the driver setting 8 to the speed sensor 7 output, and the key 13 to the controller 4 to the output of the inductive sensors 2 and 3 and disconnecting the second input of the driver 8 from the output of the inductive sensors 2 and 3 using the key 14, the second input of the regulator 4 from the output of the control signal generating unit 10 using the key 15. The essence of the control principles incorporated in the device can be understood as follows. It is known that the program for varying the heating power, minimizing the deviation of the temperature of the metal at the exit from the heater during the start-up process, is piecewise-constant. It uniquely corresponds to the temperature distribution in the metal along the length of the heater, and, consequently, the position of the point of magnetic transformations. At the same time, the temperature of the metal at the exit from the heater. In the process of implementing the optimal program is equal to the specified value, i.e. There is practically no deviation of the temperature of the metal at the exit from the heater from the predetermined value (Fig. 2). Therefore, the implementation of a closed loop feedback system on the metal temperature at the exit from the heater is not possible, since there is no deviation of the metal temperature at the exit. However, in this case, it is possible to implement a closed-loop system with feedback on the position of the magnetic transformation point, the coordinates of which are uniquely determined by the level of power supplied to the heater at each constant interval. FIG. Figure 2 shows a graph of the change in the power P of heating obtained from the conditions of the minimum deviation of the metal temperature at the exit of the heater during the spin-on process; chemical (curve SA), and the temperature of the metal at the exit of the heater (curve c); in fig. 3 - the temperature distribution in the metal along the length of the heater at different times of time T, 2, os,

corresponding to the switching moment of the power supplied to the heater.

As it follows from the graphs, there is a well-defined relationship between the coordinate point of magnetic transformations, the level of power supplied to the heater and the moments of its switching, from which the possibility of realizing a device that automatically determines the required power level at each control interval and the moments of switching from one level to another . Such a relationship can be found by the known relations, and is a piecewise constant function P (X, where RP is the power level in the nth optimal program interval;, is the corresponding coordinate of the magnetic transformation point at the end of the nth interval .

FIG. Figure 4 shows a graph of the change in heating power as a function of the coordinates of the magnetic transformation point. Here point A with coordinates corresponds to the steady state operation.

In the process of reaching the steady-state heating power, it takes in sequence the values of 1 PZ. RP 4, which correspond to the switching points

-one. .. (3

And the coordinates of the point of magnetic transformations Hc ,, X, 2 “.5 K4 KS X (Fig. 4).

As follows from FIG. 4 switching power and heating from one level to another occurs when the point of magnetic transformations reaches a certain position. This position (coordinate) is uniquely determined by the heating power level for each

the constant interval at the moment of switching, and the set of coordinates of the magnetic transformation point corresponding to the switching times from one power level to another is a straight line (BC line, fig. 4), the parameters of which are determined by known ratios. Similarly, The dependence of the power level for each subsequent interval of constancy on the coordinate of the point of magnetic transformations at the moment of switching. It is a straight line passing through a point of steady state and a point on the ordinate axis corresponding to the power level of heat loss from the surface of the heated product (sun line, fig. 4).

Further, having established the dependences of the switching points and heating power levels on the coordinate of the magnetic transformation point, it is possible to easily transform them into the corresponding voltages associated with the coordinate of the magnetic transformation points by the corresponding coefficients. Such dependencies can be realized using linear transducers made, for example, on operational amplifiers. Obtained with the help of linear voltage converters are then used to form the required law of change in heating power during heater start-up, as shown in the description of the device operation.

The proposed device enhances the accuracy of maintaining a predetermined metal temperature at the exit of the heater in transient start-up modes, which eliminates the waste from overheating of the workpieces, increases the plant capacity, and reduces the power consumption for heating.

Claims (3)

1; FERROMAGNETIC PREPARATED HEATING CONTROL DEVICE In a METHODICAL HEATING UNIT, containing an adjustable power source connected to the heater, the control input of which is connected to the controller output, two inductive sensors located outside the heater along its longitudinal axis, a mechanism for moving both inductive sensors along the heater, the input of which is connected to the output of the comparison unit, to the inputs of which are connected the output of the movement mechanism of inductive sensors, a speed sensor for moving the workpiece, characterized in that, in order to increase the output water consumption and accuracy of maintaining a given metal temperature in transitional modes of heater start-up, it is equipped with a control unit, a switching unit and four keys, the first and second inputs of the switching unit being connected to the outputs of the speed sensor and controller, and the output to the control inputs of all keys, the first of which is located between the speed sensor and the input of the comparison unit, the second is the output of the inductive sensors and the input of the controller, the third is the output of the inductive sensors and the input of the comparison unit, and the fourth is the input and output control of the control unit, one input of which is connected to the output controller, and the second - yield actuator displacement sensors. 2. The device according to claim 1, characterized in that the control unit contains a key, a comparator, an analog memory unit, two amplifiers, the output of one of which is connected to the input of the analog memory unit through a key, the first control input of which is connected to the output of the comparator, to one from the inputs of which the output of another amplifier is connected, the first input of the control unit is the second input of the comparator, the second input is the inputs of the amplifiers, and the output is the output of an analog memory unit. 3. The device according to claim 1, characterized in that the switching unit comprises a memory unit, a reference voltage source and a comparison unit, wherein the reference voltage source is connected to the first input of the comparison unit, the output of which is connected to the first input of the memory unit, the second input of which is the first the input of the switching unit, the second input of the comparison unit is the second input of the switching unit, the output of the memory unit is the output of the switching unit. SU „„ 1178782