SU873478A1 - Device for determining potential gradient in electric arc furnace arc coloumn - Google Patents

Description

one

The invention relates to electrical engineering, in particular, to devices for controlling the electric mode of an electric arc furnace.

A device is known for determining the potential of a potenzigent in a arc column of an electric arc furnace, containing a subtraction element, the inputs of which are connected to an arc voltage detecting unit, the first through the first key and the first element MEMORY, the second through the second key dividing / connected by the second entrance. through the third key with the electrode displacement sensor, and the output with the input of the second element MEMORY}

A disadvantage of this device is the low accuracy of the determination of the potential gradient and the need for efficient movements of the electrode, which causes a disruption in the electric mode of the furnace.

The purpose of the invention is to improve accuracy.

The goal is achieved by the fact that the device is equipped with a unit for determining the direction of movement of the electrode, the input of which is connected to the sensor for moving the electrode, the output is connected

through the differentiation unit to control the inputs of the first, second, third keys and the additional fourth key connected between the output of the divi- sion element and the input of the second MEMORY element, and between the third key and the second input of the divi- sion element a pulse counter is turned on.

 The drawing shows a block diagram of a device for determining a potential gradient in an arc column in a power controller of an electric arc furnace.

15 The regulator contains a unit for determining the voltage on the arc 1, the comparison unit 2, the task unit 3, the amplifier 4, the motor peremetseni electrode 5, the engine speed sensor b,

20 block to calculate the derivative

motor speed 7, threshold element 8, block 9 for detecting simultaneous termination of three arcs, block for detecting the shutdown of the furnace 10,

25 key blocks 11-14, dividing unit 15, a device for determining a potential gradient 16, a sensor for moving an electrode 17, a switching unit 18. A device for determining a potential gradient 16 contains keys

19-22, the elements of MEMORY 23 and 24, the elements of subtraction 25 and division 26, the unit for determining the direction of movement of the electrode 27, the differentiation unit 28 and the pulse counter 29.

The controller works as follows.

I When the electrode moves upwards, a signal appears at the output of the unit to determine the direction of movement of the electrode 27, which opens the key 21, takes the key 22 and enters the input of the differentiation unit 26. At the moment block 27 triggers, the output 28 of the pulse 28 appears polarity, which opens the key 19 for the time interval required for the signal from the block to determine the voltage on the arc 1 to the memory block 23. When the electrode moves up, the signals from the pulse sensor of the displacement electrode 17 are open the key 21 is fed to the input of the pulse counter 29. At the moment of the end of the upward movement of the electrode, the signal at the output of the block 27 disappears. This leads to the appearance of a negative polarity pulse at the output of differentiation unit 28, locking key 21 and opening the key 22. A positive polarity pulse at the output of unit 28 opens the key 20 for the time required for the signal to pass from the unit to determine arc voltage 1 the first input of subtracting element 25, the second input of which receives a signal from memory element 23. At the output of subtraction element 25, a signal is generated that is proportional to the voltage increment on the arc as the electrode moves upwards. This signal is fed to the first input of the element 26, to the second input of which is received the signal from the pulse counter 29, which is proportional to the amount of movement of the electrode moving up. At the output of dividing element 26, a signal is formed that is proportional to the magnitude of the gradient in the arc column | lid / d6d t which opens the 22 key 22 to the input of the memory eleidant 24 and then from the output of the MEMORY element 24 to the input of the division element 26. Any known displacement sensor, such as a photosensor, an induction sensor, in the form of a direct current motor, in which the rotor has the shape of a lobe, and the signals are taken from two pairs of poles. Depending on the order of the pulses from these pairs of poles, the direction of movement of the electrode can be determined. Thus, any movement of the electrode upwards automatically determines the magnitude of the gradient in the column

arc and the introduction of this value in

control loop.

This device allows you to improve the technical and economic performance of an electric arc furnace by increasing the accuracy of

5 in the process of melting a predetermined gain of the regulation system. The annual economic effect from the introduction of the invention is 1 million 17 thousand rubles. by increasing

0 accuracy of maintenance in the process of melting a given gain of the control system.

Claims (1)

Invention Formula A device for determining the potential gradient in the arc column of an electric arc furnace containing a subtraction element whose inputs are connected with the voltage detection unit on the arc, the first through the first key and the first element of the MEMORY, the second through the second key, and the output is connected to the first input of the division element, connected with the second input through the third key with the electrode displacement sensor, and the output with the input of the second MEMORY element, characterized in that, in order to accuracy, it is equipped with a unit for determining the direction of movement of the electrode, the input of which is connected to the sensor for moving the electrode, the output is connected through the differentiation unit to the control inputs of the first, the second, third keys and an additional fourth key connected between the output of the division element and the inputs of the second element MEMORY, and between the third key and the second input of the division element a pulse counter is included. Sources of information / taken into account in the examination 1. USSR author's certificate According to the application 2674203/07, cl. H 05 B 7/148, 1978.