SU1453625A1 - Apparatus for automatic control of billet heating temperature - Google Patents

Abstract

The invention relates to electrical engineering. The goal is to increase the performance of the complex. The device contains temperature sensors along the thickness of the workpiece, connected through nonlinear elements with parabolic characteristics to the furnace inductor power control. A setpoint adjuster and a extruder for pressing speed, a setpoint for the length and nomenclature of the workpieces, sensors for pressing and unloading the workpiece from the inductor, logic elements are entered into the device. The device allows controlling the duration of heating and pressing intervals, temperature equalization, matching heating and pressing modes for billets of various lengths, productivity increases as a result of automation from the heating process of the billet in the kiln-press complex and reducing demand. Powerful operations when changing the voltage at the clamps of the sections: inductor. 1 hp f-ly, 3 ill.

Description

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The invention relates to the induction heating of a metal prior to pressure treatment and can be used in devices for automatic control of the product heating temperature and in the technological complex an independent press furnace, which provides heating of the workpieces to a predetermined temperature with the required accuracy throughout the process for the pressing time.

The purpose of the invention is to increase the performance of the induction complex - on the furnace - press,

Fig „1 shows a block diagram of the device; FIG. 2 shows the output characteristics of a block of a log amplifier; Fig, 3 - block diagram of the trigger ,.

 Heated blanks are placed in a multi-section furnace inductor 1. Sensors 2 and 3 of the temperature respectively for measuring the surface temperature and the center of the end of the heated workpiece are located at the inductor output. The number of temperature sensors is equal to a predetermined number of control intervals, for example, two to turn on and turn off. The setting of the final temperature and heating accuracy is with the help of block 4 tasks, in the quality of which potentiometers were used as setters,

The outputs of the sensors 2 and 3 of the surface and center temperatures are connected to the first inputs of the corresponding nonlinear elements 5 and 6 with parabolic static ones: characteristics and the second inputs of the nonlinear elements 5 and 6 are connected to the corresponding outputs of the 4 task block. The outputs of the nonlinear elements 5 and 6 in series through the adder 7 are connected to the input of the first relay element 8, the output of which is connected to the first inputs of the power controller 9 of the train and the trigger unit 10,

The second input of the trigger unit 10 is connected to the output of the sensor 11 for unloading the workpiece from the inductor, for example, with a final switch / installed at the output of inductor 1.,

The direct output of the trigger block 10 is connected to the first input of the logical

And 12, the second input of which is connected to the output of the pressing sensor 13, a drill driver, an electrical contact pressure gauge mounted on a hydraulic valve.

Q

five

0

5 o

from 0 5

five

the displacement cylinder of the traverse of the press. The free movement of the crosshead of the press is carried out at the pressure of the oil in the hydraulic cy-. The lindra, not exceeding the values of Р (o ,. - 0.3) Rc, and at the pressure of the oil P (0.6–0.7) - Pj, is ensured the start of the pressing process, where PJ is the nominal pressure in the hydro- . Equal topper Therefore, when the oil pressure in the hydraulic cylinder P5tO, 6 -P is reached, a logical unit is formed at the output of the pressing sensor, which corresponds to the moment when the metal flows through the matrix, and if P 0,6- P ,, is less than zero, i.e. pressing no billet,

The gate of the logic element AND 12 and the inverse extrusion of the block of the trigger 10 are connected respectively to the second and first inputs of the logic element OR 14, the output of which is connected to the control input of the relay element 8,

The second input of the dividing unit 15 is connected to the output of the setting unit 16 of the length of the compression billet, for example, a potentiometer,.

The output of the setter 17, for example, a potentiometer, is connected to the first inputs of the first 18 and second 19 analog adders. The second input of the first analog adder 18 is connected to the q output of the sensor 20 of the pressing speed, for example, a tachogenerator mounted on a press (FIG. 3).

The output of the first analog adder 18 is connected to the second input of the second analog adder 19, the output of which is connected to the first input of the division unit 15.

The output of the division unit 15 is connected to the first input of the unit 21 of a logarithmic amplifier, the second input of which is connected to the output of the setting unit 22 of the nomenclature of the heated blanks, for example, a potentiometer. The output of block 21 of the logarithmic amplifier is connected to the first input of power regulator 9.

The third input of the logic element OR 14 and the block 21 of the logarithmic amplifier are connected to the switch 23 modes of operation. The second input of the power controller 9 is connected to the sensor 2 of the surface temperature through

3 1453f 25

the second relay element 24 is limited to the product. In this case, the heating time

nor the maximum temperature.

The trigger block 10 contains: IK-trigger 25, logic elements OR 26, AND-NOT 27, OR-NOT 28 and two keys, Start 29 and Failure 30.

The device works as follows.

When power is supplied to the device by the operator, a pulse is generated from the key. Start 29 of the block of trigger 10, which through logical elements OR 26, AND-NOT 27 enters the first and second inputs of the TC-trigger 25 (the third input of the 1K-trigger 25 also receives a logical unit from of the OR-NOT 28 logic element, since there is no contact between the thermocouples and the output, the workpiece in the inductor 1) At the output of the 1K flip-flop 25 and, accordingly, at the output of the block of the flip-flop 10, the following information is generated: the first-direct output is logical 1, the second-inverse is logical Oh and podg The device is pressed for operation.

In the case of a two-interval control, temperature measurement sensors are used at two points along the thickness of the workpiece, for example, in the center of TC and on the surface T "of the workpiece. The control system provides heating in two intervals. In the first control interval, 35 presses are connected to the clamps;

with the voltage, in the second interval, the voltage is disconnected. The total time of the two-part control of the induction heater t is provided by the device during the time of compression.

Sovani -, where L is the length of the compression billet, m; V is the pressing speed, m / min. Therefore, the heating time ty of the product at a given temperature and 45 and the output of the signal is formed, which is equal to the current pressing speed.

equal to zero, which ensures the normal operation of the remaining blocks of the device. .

The second adder 19 performs the algebraic addition of the input signals to the inputs, i.e.

V - V, 17 - "

W, h 7or

The distribution capacity over the volume of the ingot is determined by the power (voltage, i.e.

em) supplied to the sections of the inductor. The unit 15 of the axis of the axle; there is a de- magnitude of the power expenditures for the compensation of the signal received from the set of heat losses from the surface by 50–16 length, i.e. on the signal.

heated ingots in this case will be less, i.e. q, q ,, if

 so se

t g

 t

wed

where d, „, is heat, the apparent loss from the surface of the heated ingots, respectively, at average temperatures T and 7. Therefore, the proposed device connects the clamps of the sections to a voltage only after the occurrence of the pressing process

those. duration of heating and temperature equalization intervals at the end

T and. t.

   and,

chod

-e;

where, t.

respectively, the minimum and maximum temperature of the ingot; , S - respectively set temperature and heating accuracy.

The specified heating mode in the furnace-press complex is provided by automatic change at the clamps of the voltage sections, at which the billets with durable parameters are heated for a period of time determined by the pressing time of the pre-heated ingot. To do this with the master dial

17 sets the pressing speed V,., And the setting device 16 defines the length of the pressed workpiece Ljg. The first adder 18 compares the current and set pressing speed. On

The output of the adder 18 produces a signal equal to.

y - y 16 P

 , if uh,

 2O

u oh if u

0

W

to

47

where y is the output information of the n-block.

This allows, when moving the press bar in the interval between pressing at a speed of several ten times more than the speed of the press.

and an output "signal is generated equal to the current pressing speed.

equal to zero, which ensures the normal operation of the remaining blocks of the device. .

The second adder 19 performs the algebraic addition of the input signals to the inputs, i.e.

and the output "form current soon

V - V, 17 - "

W, h 7or

approx 15 signals of 16 lengths

coming from the second analog adder 19, i.e. y,, and a signal is generated at the output, directly proportional to the pressing time.

s

 F. Output signal

 V |, p

block 15 division, proportional

pressing time, enters on

 input of the logarithmic amplifier unit 21, the output characteristic of the logarithmic amplifier unit 21 (Fig. 2) almost repeats the dependence of the power (voltage) applied to the clamps of the sections providing the required heating parameters during the pressing time. The slope of the output characteristic depends on the nomenclature of the ingots being heated and has a different appearance for each nomenclature. The required slope is provided by means of the setpoint adjuster 22.

At the output of the burdock element 8, a signal is formed, which, through the power regulator 9, connects the voltage to the terminals of the inductor 1 and transfers the 1K-trigger 25 of the trigger block

At the output of block 21, logarithmic, du to the zero state, i.e. For the first amplifier, a signal is generated which is a direct output - O, the second - the other one is fed to the third input; the control output is opposite - 1. Logical power 9 and if there is a resolution from the second output of the trigger unit

a thawing signal to turn on from the river through the second input of the logic element 8 produces a voltage at the terminals of the heating block sections OR 14 allows the relay element 8 to work until the end of the heating process.

l, which provides heating of products with specified parameters during pressing. At the same time, due to temperature feedback — blocks 2 and 3 —T “, TC, nonlinear elements 5 and 6, adder 7, a signal is generated at the output of relay element 8 that determines the duration of heating and temperature equalization. At the output of relay element 8 a signal for applying voltage to the clamps of sections through the power regulator 9 only when the enabling signal arrives at the second input from the logic element OR 14. This signal is generated after unloading the heated billet and pressing it as follows. When moving the crosshead of the press back or forward without contact with the workpiece. The oil pressure in the hydraulic cylinder P - “: 0.6 P, the pressing sensor 13 forms a logical zero and at the output of logic blocks AND 12, OR 14 also logical zeros, which prohibit forming the output of the relay element 8 is an enable signal for switching on, although at the output of the adder 7 an information signal is generated for enabling the power to be turned on, since D t Tc T "-. .

As soon as the ram of the press reaches the billet in the container and the pressing process occurs, the oil pressure in the hydraulic cylinder will increase by more than 6 ° C, the press sensor 13 forms a logical unit.

which through logical blocks AND YY, OR 1A goes to the second input of the relay element 8 (logical input from the trigger block 10 also goes to the second input of the element 12, because the initial state of the output information from the trigger block 10 next: first - 1 the second is O).

At the output of the burdock element 8, a signal is generated, which, through the power regulator 9, connects the voltage to the terminals of the inductor 1 and transfers the 1K-trigger 25 of the trigger block

zero state, i.e. Peru through the second input logical

the OR 14 block allows the relay element 8 to operate until the end of the heating process.

To ensure the required temperature distribution, the device switches from the first control interval to the second (power switching (voltage), the value of which is formed by the output signal 21 of the logarithmic amplifier) at certain values of the surface temperature T and center TC. All the initial states of the answer

plane

and Ti,

slips into

the structure of the power switching temperature curves (switching lines), each of which is described by the equation F (T, TC) O, and with a sufficient degree of accuracy, the function F (Tf, TC) is determined by the sum of the square dependences on each temperature Tp and TC and can be represented as follows:

F (T

P

0+ a, T „-ь

+ B „

B, TC +

B f 2 - -C "

where EO, b.

 -t FOR.

H

0

- calculated factors. Square functions E, (Tn)

+ hell „+

agT ;,

0+ b, TC + are reproduced with nonlinear elements 5 and 6 with parabolic static characteristics, and g with the value of Р (Тп, Тц) equal to the sum of Г, (Т „) 4- Р (Тц) corresponds to the output signal of the adder 7.

Relay element 8 is an analog-to-digital conversion.

The tele is a comparator that generates a signal to turn on and off the voltage on the clamps of the inductor sections 1.

At the end of pressing from the output of sensor 13, a logical zero is formed, and if the workpiece is not unloaded, the device provides a thermostat mode, since a logical unit is formed from the second output of the 1K-trigger 25 of the trigger unit 10. When unloading the output billet with the required parameters from the sensor 11 of the consumer, a pulse is generated, which reaches the first input of the trigger unit 10 and through the OR element 26 changes the state of the trigger 25 to a single, i.e. from the first direct output — logical 1; from the second inverse — logical O. Next, the operation of the device is repeated.

The switch 23 of operating modes has two positions: the first, when the press and the heater work together, has a logic output at the output of the block of the logarithmic amplifier 21 and the OR 14 element depends only on the signals arriving and the first two inputs. If the induction heater 1 operates in the Start mode or in other transient modes, in which unloading of ballast or substandard blanks is possible, the switch 23 is shifted to the second position, the logical 1 is formed at the output, which at the output of the log amplifier 21 generates a signal at which at the output of the power regulator 9 a maximum voltage is formed, i.e. maximum power is supplied to the clamps of the sections: (In addition, logical 1 from the switch of 23 operating modes through the element. OR 14 to the relay element 8 generates an enabling signal, which depends on the operation of the press.

In case of a short-term loss of supply voltage on the device during the pressing process of the product, the state of the trigger 25 of the block of the trigger 10 will be undefined, the operator pressing the key Fault 30 of the block of the trigger 10 transfers the trigger 25 through the element OR-NOT 28 to the next state: my output is logical o, the second inverse is logical

eight

1. It allows for continued operation of the device. In the short-term absence of the supply voltage on the device at the moment when the pressing is finished and the output billet with the required parameters is unloaded from the heater, the operator, pressing the Start key 29,

0 fixes the single state of the IK trigger 25 of the trigger block 10.

Example. The proposed device was tested on an IN-800 furnace with a capacity of up to 24 kW, the total installation length is 6,630 m, and the mains frequency is 50 Hz.

The parameters of the heated billets: length 1710 mm, diameter 485 mm, material - aluminum alloy AMG-6, the final heating temperature,

0 heating accuracy, pressing speed 0.1 m / min.

The control over the operation of the device is carried out with the help of two six-; point potentiometers type KSP-4

5 and thermocouples of type ХА, staked on the surface of the workpiece through 100 mm, voltmeters mounted on the clamp, max. Of each section.

With the help setters set

0 the corresponding parameters of the workpiece and the heating temperature. When the device is turned on, the tension of 358 V is automatically set at the section clamps. After 15 min 40 s, the installation is disconnected from the supply voltage and at the moment of the end of the pressing, i.e. after 16.5 minutes, the temperature of the exit billet corresponds to the required heating parameters. When unloading the heated product, a control measurement of the temperature on the ingot surface is carried out - the temperature corresponds to the required parameters.

The heating of the subsequent billet to the required parameters begins only after the moment when the unloaded billet is pressed. When the pressing speed is changed, the device forms a voltage on the clamps of the sections in inverse proportion to the pressing speed and ensures the required heating parameters of the output billet by the time the pressing ends.

The device allows to automate the process of heating the blanks in the furnace-press production complex, to increase productivity by reducing auxiliary operations.

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Claims (2)

1. A device for automatically controlling the heating temperature of billets in an induction furnace-press production complex, which contains at least two temperature sensors for the thickness of the billet, including the surface and center temperature, the outputs of each of which and the outputs of the temperature setting unit are connected 15 to the inputs of nonlinear elements with parabolic characteristics connected by outputs through a series-connected adder and a first relay element with a first input of a power inductor a furnace, and a second relay element through which the output of the surface temperature sensor is connected to the second input of the power regulator, which requires that, in order to increase the productivity of the complex, a setter and a pressing speed sensor, a setter of length and nomenclature are introduced into the device preforms 39 sensors pressing and unloading the workpiece from the inductor, the logarithmic amplifier block division, two analog adder, logical OR elements, and, a trigger unit and a mode selector switch, yield ³⁵ za- forging speed sensor it is connected to the first inputs of both analog adders, the second input of the first of which is connected to the pressing speed sensor, and the output is connected to the second input of the second analog adder, the output of which is connected to the first input of the division unit connected to the second input with the length of the pressed workpiece, and the output - with the first input of the logarithmic amplifier, the second input of which is connected with the master of the range of blanks, the third with the switch of operating modes, and the output of the logarithmic amplifier with the third input of the power reg insulator power output of the first relay element is connected to a first input of a trigger unit, a second input coupled to an output of the sensor workpiece unloading inductor direct its output - to the first input AND gate, and. inverse output - with the first input of the OR element connected to the second input with the output of the And element, the third input with the mode switch, and the output with the control input of the first relay element. 2. The device pop. ^ characterized in that the trigger unit contains an IK trigger, AND-NOT, OR, OR-NOT logic elements and two keys for signaling the Beginning ”and“ Failure, ”the key's output is connected to the first input of the OR element connected to the output with the counting input IK -trigger, and with the inputs of the AND-NOT element connected by the output to the K-input of the IK-trigger, the output of the Fault key ”is connected to the first input of the OR-NOT element connected by the output with the R-input of the IK trigger, and the first input of the block. The trigger is the second input of the OR-NOT element, the second input, the second input of the OR element, and direct and inverse outputs - direct and inverse outputs of the IK-trigger.