SU673859A1 - Melt level motion - Google Patents

Description

one

The invention is intended for use in electrothermal installations, especially ore-thermal electric furnaces.

A device is known for controlling the level of the melt in the bath of the ore-thermal furnace, which implements the measuring method, which means that a measuring probe is introduced into the furnace bath through the axial channel in the furnace unit and the voltage is measured between the probe and the electrode through which the probe is introduced 1. However, the known device is characterized by low reliability. The closest to the invention in its technical essence is a control device comprising a uniformly moving measuring probe, a drive for moving the probe, a drive control unit, a probe-electrode voltage meter and an indicator. The probe is a wooden rail with a special coating inside which molybdenum wire 2 is laid. The control of the melt level in the bath of the ore-thermal furnace by this known device is associated with a large number of manual operations requiring special skills (visual determination of the moment of contact of the melt mirror by the oscillogram, calculation of the time of the probe movement from the initial moment until the moment when the probe touches the melt mirror, determination of the melt level in the bath by the velocity of the probe, reverse of the drive emescheni probe for measuring the end), which reduces the efficiency of the measurement, results in fatigue of the operator and causes a significant re measurement error.

The purpose of the invention is to improve the accuracy and speed of determination of the level of the melt in the bath. In the proposed device, this is achieved by the fact that it is equipped with a differentiating

and integrating units, comparison and lagging units and a two-way relay unit, the input of the differentiating unit connected to the output of the voltage gauge probe-electrode, the output of the differentiating unit connected to one input of the comparative unit directly, to the other input through the delaying unit, and the output of the comparison unit connected to the input of the on-off relay unit.

through the contacts of which the output of the integrating unit is connected to the indicator, and the input of the integrating unit is connected to the source of stabilized voltage through the contacts of the drive control unit.

FIG. Figure 1 shows the dependence of the voltage of the probe electrode on the position of the end of the measuring probe; in fig. 2 is a schematic diagram of the proposed device.

The analysis of the dependence of the voltage probe – electrode shown in FIG. 1 shows that the moment of contact of the melt with the mirror probe can be determined by comparing the derivatives of the change in the voltage of the probe – electrode over time, taken with a slight shift in time. This principle is based on the operation of the proposed device, which contains a uniformly moving probe (not shown), a drive 1 for moving the probe, a drive control unit 2, a voltage probe 3, a probe electrode, a differentiation unit 4, the input of which is connected to a voltage meter output probe -electrode, comparison unit 5, one input of which is connected directly to the output of differentiating unit 4, and the other input is connected to the output of differentiating unit through delay unit 6, on-off relay unit 7, input which is connected to the output unit 5, an integrating unit 8, which input through contact block 2 is connected to a DC voltage in magnitude, the LED 9, the input of which contacts through a two-position relay unit 7 connected to the output of the integrating unit.

When the start button (start of measurement) is pressed, the Uniff voltage is applied to the winding of the P-block 2 relay. With the help of the IP contactor, the relay P is locked, and it remains on after the start button is released. By contacts 2P and ZRG, the control unit includes a drive for moving the probe. Using contacts 4P | and 5Pi, a constant voltage is applied to the input of the integrator unit 8. The output of the integrating unit 8 produces a signal proportional to the amount of movement of the probe. The signal proportional to the voltage of the probe electrode from the output of the meter 3 is fed to the input of differentiating unit 4. From the output of block 4, a signal proportional to the derivative voltage of the probe electrode over time is fed to one of the inputs of block 5 and to the input of block 6. From the output of block 6, the signal, shifted respectively in time, is fed to the second input of block 5. The difference between the signals coming from the outputs of differentiating block 4 and block 6 of delay is fed to the input of the on-off relay block 7. When the probe of the melt mirror touches the signal taken directly from the output of differentiating unit 4 becomes smaller than the signal.

block 6, which triggers the relay Pi of the on-off relay block 7. Through the 4Pi and 5Pi contacts, the indicator input is connected to the output of the integrating unit 8. As a result, the value is fixed on the indicator

and Ucoriif t () Л - Лрр, where K is the scale factor;

 - distance from fixed

the starting point of the probe movement before the furnace;

t is the time from the beginning of the probe movement

from a fixed point to the melt level;

V is the speed of the probe;

and const - input voltage

integrating unit;

A is a constant value. The measurement accuracy is determined by the response threshold of the on-off relay unit and the delay value of the delay unit, setting which achieves the required sensitivity of the proposed device for determining the level of the melt in the bath of the ore-thermal furnace. The automatic reversal of the probe movement drive is carried out using the contacts IPi-ЗРг.

After the probe returns, the circuit is reset to its initial position, and the Reset button is pressed on the integrating unit.

Claims (2)

1. USSR author's certificate No. 347953, cl. H 05 B 7/144, 1969. 2. Short V. Century Development and study of the problems of the production of phosphorus and its products. Works of Lennyigiprokhim, vol. 10, L., 1974, p. 18-23. hs to zoid Pete V s-e