SU1457175A1 - Sectionated electrothermal installation - Google Patents

Abstract

The invention relates to electrical engineering. The goal is to increase the reliability and accuracy of maintaining power. The installation contains one adjustable section of heaters, connected to an adjustable power source, and at least one unregulated section connected to an unregulated power source through the executive unit, the sensor of the total power of all sections, the output of which is connected to the regulator input connected to the output adjustable power source. The installation contains a reversible counter with a decoder, an RS flip-flop, a pulse generator, a pulse shaper, two AND elements, an inverter, and an OR element switch according to the number of unregulated sections. The controller output is connected via a pulse shaper to the trigger input of a pulse generator connected to the counter input and trigger inputs, the first input of which is connected to the first And gate connected by the second input to the signal output of the counter and the output. with his 1m output. The second input of the trigger is connected to the first input of the second El-I connected by the output to the summing input of the counter, and the second output to the output of the switch. The same outputs of the decoder and the input of the switch and all of the OR elements are combined, the number of inputs of the switches being equal to the number of unregulated sections, and the number of inputs of each EL element OR equal to the number of this element. 1 il. (Q (L 4 cl

Description

I

The invention relates to electrical heating and can be used in furnace and autoclave equipment.

The purpose of the invention is to increase the reliability and accuracy of power maintenance.

The drawing shows a diagram of the installation with four unregulated sections of electric heaters.

The installation contains unregulated sections 1-4, controller 5, driver 6 pulses, generator 7 pulses, reversible x: meter 8, decoder 9, switch 10, elements ISH 11-14, executive units 15-18, power sensor 19, an adjustable section 20, an adjustable power supply 21, an inverter 22, elements And 23, 24, and an RS flip-flop 25.

The installation works in the following way.

Reversible counter 8 is in the zero state. When the value of the output signal of the regulator 5 changes, the control power supply 21 smoothly changes the power of the regulated section 20. At; Attented 1 by the output of the controller 5 of the specified maximum value, the driver of the 6 pulses sends a trigger signal to the pulse generator 7 and to the control input of the RS flip-flop 25, since the output of the decipher 9 is zero and the switch 10 is in position 4 (connected to the fourth output decoder 9), Then at the second input of the second element And 24 there are units. This time is determined by the inertia of the object and the control system for testing the parameter (temperature).

With a further increase in the output signal from the controller 5, the input power of the regulated section 20 increases. For a given value, the driver 6 pulses allows the start of the generator 7 pulses.

The following section of electric heaters is switched on. After the fourth pulse from generator 7

pulses on the decoder 9 a single signal will be on the fourth discharge, which corresponds to the inclusion of all sections of electric heaters 1-4. The same single signal through the switch

A small signal from the inverter 22. Unit-20 generates a zero signal to the inverton signal from the output of the RS flip-flop 25 through the first input of the second element AND 24 to the summing input (+1) of the reversing counter 8 and allows the score to increase.

From the pulse generator 7, counting pulses begin to arrive at a given frequency.

After the first pulse on the first digit of the decimal decoder 9, a signal 1 appears, which through the first element OR 11 and the execution unit 15 turns on the first electric element of the second output of the pulse former 6 sends a single signal to the reset input of the RS flip-flop 25. With the pulse former 6. A signal is given to start the generator 7 with an immersion heater 1. To the negative input of the regulator 5 from the power pulse sensor 19. Since the reversible counter receives a signal, the corresponding 8 is not in the zero state, 1 TION of on power. The signal on its signal output appears on the output of the controller 5 and the adjustable signal 1. This signal comes

The power supply source 21 decreases, the second input of the second element And 23 is reduced. Peace: A spruce of 6 pulses stops 40 A single signal from the trigger output gives the trigger signal to the generator 725 through the first input of the second pulse signal. The reversible counter and the AND 23 inputs to the subtracting input of the ger 25 are in a stable one (-1) reversible counter 8 and in a different state. The trigger 25 defers the score downward. By

steady state for inputs 45 to the signals of the generator 7 of the pulses of the diverging counter 8 with possible fluctuations of the output signal of the regulator then | a 5 in the zone of maximum and minimum

The unit starts operating in the off mode of the electric heater sections 1-4. After successive shutdown of all electric heating sections, the settings of the controller 5 can be gg reversible counter 8 switches such that when the next one is connected to state 0, the lower section of the electric heater does not change instantly, but. it takes time to change the basis of a single signal from the second input of the second element And 23 and the work of the live input is blocked (-1)

55 reversive counter 8. The maximum input of the controller 5. Therefore, the number of controlled in a particular

in the case of sections of electric heaters, it is determined by the position of the switch g 10.

This generator 7 pulses determines the frequency (speed) of connecting and disconnecting sections of electric heater 22, thereby blocking the operation of the summing input (+1) of the reversing counter 8. If the generator 7 pulses continues to work in full on-power mode, it does not change sustainable state of the scheme.

When the output of the regulator 5 reaches the specified minimum value

The second output of the pulse driver 6 is supplied with a single signal to the reset input of the RS flip-flop 25. With the pulse driver 6, a signal is sent to start the pulse generator 7. Since the reversing counter 8 is not in the zero state, AND 23 appears at its signal output to the subtractive input (-1) of the reversing counter 8 and allows the count to decrease. By

On the other hand, the reversible counter 8 goes to state 0, and the

A single signal is received from the second input of the second element AND 23 and the operation of the input input is blocked (-1)

The change in the input power in the direction of increase or decrease in the pro- comes automatically from any state of the reversible counter 8. The sections can also be switched off when not all sections of the electric heaters 1-4 are turned on, which is determined by the regulator 5.

When a sectioned electrically connected to an adjustable source of the heating installation is in operation, some sections of electric heaters may fail. This does not violate the logic of the circuit. The next impulse from the generator of 7 impulses will turn on the next serviceable section. The unit allows sequential control of the remaining sections of the electric heaters.

After the unit is turned on in an emergency mode, the command Set Zero applied to the R input of the reverse counter 8 is used to set the reversible counter 8 to the zero state.

The pulse frequency from the pulse generator is determined by the inertia of the control object and the characteristics of the electric heaters. For autoclave equipment, it is 2-25 seconds. The pulse duration is 20 NS when used in the circuit of modern electronic devices. The input of the regulator 5 receives a control current signal from the control system.

The capacity of the sections and their number can be arbitrary. With the help of switch 10, the maximum used power of the entire sectioned electric heating installation is set. The capacity of the adjustable section must exceed the capacity of any adjustable section.

In this example, the sections of electric heaters 1-4 by 120 kW, the power of the adjustable section 4-145 kW.

The use of the proposed installation of the D elements OR connected to the controls allows to ensure smooth and scaling inputs of the execution block control of the supplied power.

and improve the reliability of the control system.

Claims (1)

Invention Formula A sectioned electrothermal installation comprising one adjustable section of electric heaters. power supply, and at least one unregulated section, intended for connection to an unregulated power source through execution units, full power sensor all the included sections, the output of which is connected to the input of the regulator, connected to the control input of the regulated power source, In order to increase reliability and accuracy of power maintenance, the installation is equipped with a reversible counter with a decoder, RS trigger, pulse generator, pulse shaper, two AND gates, an inverter, a switch and OR elements by the number of unregulated sections, regulator output through the pulse driver is connected to the trigger input of the pulse generator connected to the counter input of the counter and the trigger inputs, the first output of which is connected to the first the input of the first element I connected by the second input to the signal output of the counter, and the output to the subtractive input of the counter, the second output of the trigger is connected to the first input of the second element I connected to the summing input of the counter, and the second input through the inverter with the output of the switch , the decoder outputs of the same name and the switch inputs the bodies and all elements of the IL are combined, and the number of inputs of the switch is equal to the number of unregulated sections, and the number of inputs of each element OR is equal to the number of this element, and the output