KR200278284Y1 - Fault prevention device of strip in electrolytic tank - Google Patents

Abstract

The present invention relates to an electrolytic cleaning facility for a continuous annealing facility in a steel mill, and more particularly, electrolysis which detects and prevents the occurrence of bonding of a strip due to contact between a strip and an electrode plate in the course of passing through an electrolytic tank. A defect preventing device of a strip in a tank.

To this end, the present invention calculates the deviation between the output value of the DC current sensor and the current setting value for detecting the current applied to the electrode plate, and when the deviation is larger than the predetermined deviation upper limit setting value, the first compensation value is proportional to the difference. Calculate Further, the initial tension setting value of the payoff reel and the first compensation value are added together to calculate the difference between the drive voltage of the current payoff reel motor and the reference voltage. At this time, when the value is larger than the sum of the tension setting value and the first compensation value, the second compensation value is calculated by proportionally integrating the tension setting value, the first compensation value, and the motor driving voltage deviation. The tension of the payoff reel is controlled by the compensation value to increase the tension of the strip in order to suppress the occurrence of defects in the strip when it is detected that the strip is in contact with the electrode plate.

Description

Fault prevention device of strip in electrolytic tank

The present invention relates to an electrolytic cleaning facility for a continuous annealing facility in a steel mill, and more particularly, electrolysis which detects and prevents the occurrence of bonding of a strip due to contact between a strip and an electrode plate in the course of passing through an electrolytic tank. A defect preventing device of a strip in a tank.

1 is a view showing the configuration of an electrolytic tank constituting a general electrolytic cleaning equipment. As shown in FIG. 1, the continuous annealing facility of an ironworks has an electrolytic cleaning facility for removing foreign substances such as oil, dust, etc. on the surface of the strip, which must be generated during cold rolling of the strip 21. ) Is installed. The electrolytic tank 12 constituting the electrolytic cleaning equipment 10 is provided with a plurality of electrode plates 22 up and down in an electrolytic tank containing soda solution (NaOH), and the first and first It is comprised so that a strip may pass between the positive electrode plates 22 in the state which energized low voltage, high current from the 2 power supply parts 30a and 30b. Therefore, the fine foreign matter adhering to the strip surface is removed by the electrohydrogenation reaction on the strip surface via the soda solution while the strip 21 passes between the electrode plates 22.

When the tension applied to the strip 21 passing between the two electrode plates 22 during the continuous foreign material removal operation is caused by the stripping or being oriented in one direction due to factors such as control and poor shape of the strip, the electrode plate 22 is applied to the electrode plate 22. There is a problem that the strip 21 is in contact with the strip surface with the arc traces on the strip surface to lose the value as a product. In addition, in the case where the strip and the electrode plate are severely contacted, the damaged part of the surface of the strip caused by the electric flame is generated until it does not bear a certain tension and is broken.

On the other hand, in order to identify the occurrence of the strip defect in the electrolytic tank, the strip surface inspector at the exit of the electrolytic cleaning equipment performs a periodic sample inspection of the strip to confirm whether the defect occurs. However, even in this case, since continuous strip surface inspection is not performed, if the strip surface defects are intermittent and irregular in shape, a considerable amount of time is required to take action even when the strip surface defects cannot be identified or identified. As such, there was a problem of lowering the productivity of the product.

Therefore, the present invention has been devised to solve such a conventional problem, and its purpose is to detect the moment when the surface of the strip, which is moved between the electrode plates of the electrolytic tank, is in contact with the electrode plate, so that it can be immediately applied to the strip when bonding of the strip surface occurs during operation. It is an object of the present invention to provide an apparatus for preventing defects in strips in an electrolytic tank, by adjusting the tension applied to eliminate defects and preventing the occurrence of defects in the strips.

1 is a detailed view showing the internal structure of a general electrolytic tank.

2 is a schematic configuration diagram of a general electrolytic cleaning facility for implementing the present invention.

3 is a circuit diagram showing the electrical configuration of the defect prevention apparatus of the strip in the electrolytic tank according to the present invention.

4 is a current waveform diagram when a defect occurs in a strip in an electrolytic tank.

5 is a current comparison diagram of each circuit unit according to the present invention when a defect occurs in a strip.

Explanation of symbols on the main parts of the drawings

12.Electrode Tank 20 ... Payoff Reel

21 ... strip 22 ... electrode plate

30 Power supply 33 DC current sensor

34.Polar switching switch 40 ... Actual current detector

50 ... Current setting section 60 ... Comparison section

70 ... upper limit setting part 72 ... first diode

73 ... Schmidt Rejection 74 ... Alarm buzzer

75.Welding switch 80 ... Reset circuit

90 1st tension compensator 100 tension setting part

110 2nd tension compensator 120 motor drive control part

130.Payoff reel drive motor VR1 ~ VR4 ... Variable resistor

In order to achieve the above object, the defect prevention apparatus of the strip in the electrolytic tank according to the present invention removes foreign substances on the surface of the strip by passing the strip between the two electrode plates in a state in which electricity is supplied to the electrode plate inside the electrolytic tank containing the electrolyte. A strip control apparatus in an electrolytic tank of an electrolytic cleaning facility, comprising a payoff reel for maintaining a tension applied to the strip and a payoff reel motor for driving a payoff reel.

A current sensing unit detecting a change in current applied to the electrode plate, a comparing unit comparing the actual detected current value sensed by the current sensing unit with a reference current value set by the user, and calculating the difference; A deviation upper limit setting unit configured to set an upper limit on the deviation between the current value and the reference current value, a first tension compensation unit calculating a tension compensation value proportional to the deviation when the deviation value output from the comparison unit is greater than the deviation upper limit value; And a tension setting unit configured to receive the initial tension value of the payoff reel, the tension setting value and the tension compensation value, and calculate a difference between the actual driving voltage and the reference voltage of the payoff reel motor to obtain a tension setting value and tension. And a second tension compensator for controlling the drive of the payoff reel motor based on the compensation value and the final tension compensation value due to the motor driving voltage deviation. The.

Hereinafter, with reference to the accompanying drawings, the configuration and operation effects of the defect prevention apparatus of the strip in the electrolytic tank according to a preferred embodiment of the present invention will be described in detail.

First, a schematic system configuration of an electrolytic clean facility for implementing the present invention will be described. Figure 2 is a system layout showing a schematic configuration of the electrolytic cleaning equipment for implementing the present invention. As shown in FIG. 2, the electrolytic cleaning equipment 10 for implementing the strip defect prevention apparatus of the present invention primarily cleans the strips introduced through the strip transfer unit 15 including a plurality of rollers. A primary washing tank 11 and a soda solution (NaOH 2%) are contained therein, and a plurality of electrode plates 22 are installed up and down therein, and low voltage (DC 4V) at both ends of each electrode plate 22, Rinsing of the electrolytic tank 12 configured to pass the strip 21 between the positive electrode plates 22 while the electricity of the high current 6000A is energized, and the strip from which fine foreign substances have been removed in the electrolytic tank 12 are performed. The rinsing tank 13 and the dryer 14 for drying the rinsed strips, the welder 16 for welding the end of the strip to remove the foreign matter and the end of the newly supplied strip, and the electrolytic tank 12 DC motor to adjust the tension (tension) of the strip 22 is introduced into the Surface comprises a pay-off reel (payoff reel) (20) which is driven by a not illustrated).

3 is a circuit diagram showing the electrical configuration of the strip defect prevention apparatus in the electrolytic tank according to the present invention. As shown in FIG. 3, the apparatus for preventing strip defects in the electrolytic tank according to the present invention is a power supply unit 30 for supplying electricity of low voltage and high current to the electrode plate in the electrolytic tank, and is supplied to the electrode plate from the power supply unit 30. A DC current sensor 33 for detecting a change in current, an actual current detector 40 for amplifying a supply current value of an actual electrode plate detected by the DC current sensor 33, and a variable resistance value set by a driver A current setting unit 50 for amplifying and outputting a current value, a comparison unit 60 for comparing the output current values of the actual current detection unit 40 and the current setting unit 50 and outputting a deviation between the two values; The comparison unit 60 is larger than the deviation upper limit value of the deviation upper limit value setting section 70 and the deviation upper limit value setting section 70 for setting the upper limit deviation between the current value actually applied to the electrode plate 22 and the current value set by the operator. If the deviation value from the output is larger The first diode 72 is connected, the Schmitt trigger unit 73 for driving the alarm buzzer 74 as the first diode 72 is turned on, and the pay-off when the first diode 72 is turned on. A first tension compensator 90 having a small DC motor driving resistor 93 to increase the tension of the reel 20 and outputting a first tension compensation value obtained by proportional integral operation according to the actual current detection; The tension setting unit 100 receives an initial reference tension value of the payoff reel 20 from the operator, and the first tension compensation value and the tension setting unit 100 output from the first tension compensator 90. A second tension compensator 110 for outputting a second tension compensation value, which is a final tension compensation value through proportional integral operation based on a difference between the tension set value and the pay-off reel driving motor 130, and a reference voltage; Pay according to the second tension compensation value output from the second tension compensation unit 110 It is provided with a motor drive control unit 120 for controlling the drive power of the DC motor 130 for driving the reel (20).

In addition, a reset switch for resetting the operation of the welding machine switch 75 whose contact is turned on / off in accordance with the driving of the welding machine 16 and the DC motor driving resistor 93 in accordance with the driving of the welding machine switch 75. It further comprises a set circuit portion 80.

In the above-described configuration, the power supply unit 30 that applies a low voltage and a high current to each electrode plate 22 in the electrolytic tank 12 receives AC power to transform the transformer 31 through the transformer 31 to change the rectifier 32. Through rectification and smoothing, low voltage and high current are applied to each electrode plate. In addition, the power supply unit 30 includes a polarity switching switch 34 to switch the polarity of the power applied to each electrode plate at each operation of the welding machine 16.

Hereinafter, the operation of the strip defect prevention apparatus in the electrolytic tank according to the present invention.

As shown in FIG. 2 and FIG. 3, the strip 21 supplied through the primary cleaning tank 11 into the electrolytic tank 12 is positioned in the electrolytic tank 12 up and down in the electrode plate 22. In this case, the electrolytic solution is electrohydrogen decomposed by the electrode plate 22 which is supplied with electricity of low voltage and high current through the power supply unit 30 to remove fine foreign substances on the surface of the strip.

The change of the current applied to the electrode plate 22 is detected by the DC current sensor 33, and the detected current value is applied to the non-inverting amplifier 41 of the actual current detection unit 40. The current detection signal applied to the non-inverting terminal (+) of the non-inverting amplifier 41 of the actual current detecting unit 40 is amplified by a predetermined amplification ratio to some extent and in phase with the inverting terminal (-) of the comparator 61. It is output at the detected current value of (+ potential).

On the other hand, the current setting unit 50 sets a constant current value (current value when the detection current of the electrode plate due to contact of the strip and the electrode plate reaches the ground current value) set by the variable resistor VR1 from the user. This is input to the inverting terminal (-) of the inverting amplifier 51, the input current set value is phase inverted (-potential) is input to the inverting terminal (-) of the comparator 61.

The comparator 60, which receives the actual current detection value and the current setting value from the real current detector 40 and the current setter 50, respectively, calculates the deviation between the two current values, and inverts the calculated deviation value. It outputs to one diode 72 side. At this time, the first diode 72 is turned on when the deviation value output from the comparator 61 is larger than the deviation upper limit set by the variable resistor VR2 of the deviation upper limit setting unit 70, and when it is small, the first diode 72 is turned off. Will be maintained. That is, when the detected current value for determining whether the strip is defective due to the contact between the electrode plate and the strip is greater than the preset reference current value (when a potential is applied), the first diode 72 is turned on to generate the first current. When the tension compensation unit 90 is driven and the difference between the detected current value and the set current value of the electrode plate 22 is smaller than the upper limit deviation value, the first diode 72 maintains a non-conductive state because it is a temporary current change. The driving of the first tension compensator 90 is turned off.

In addition, as the first diode 72 is turned on, the Schmitt trigger unit 73 is operated to drive the alarm buzzer 74. As an embodiment, when a voltage of 300 [mV] or more is applied to the input terminal of the Schmitt trigger unit 73 as a negative potential, an output voltage of DC 24 [V] is generated, and thus a 24 [V] relay is operated. The alarm buzzer 74 is driven. Therefore, the operator can identify whether a strip defect is generated by the operation of the alarm buzzer 74.

On the other hand, the inverting amplifier 91 of the first tension compensator 90 phase inverts the current deviation value applied from the comparator 61 to the deviation value of the positive voltage in accordance with the conduction of the first diode 72 to direct current. To the motor 92. The DC motor 93 receiving the positive voltage is driven counterclockwise to adjust the variable resistor VR3 so that the output voltage is increased, and the first proportional integral amplifier 94 receiving the increased output voltage is the current. The first tension compensation value increased by a certain amount in proportion to the deviation value is output to the second tension compensation unit 110.

The second tension compensator 110 receiving the first tension compensating value receives the tension setting value and the first tension compensating value of the tension setting part 100 which is set as the tension setting value of the pay-off reel at the beginning of operation by the operation operator. Add up. If the summed tension compensation value is smaller than the output value of the second proportional integral amplifier 111 which proportionally integrates the difference between the reference voltage v-ref and the actual voltage v-act of the payoff reel motor 130, The two diodes 113 are conductive, and in the opposite case, the second diode 113 is non-conducting. Therefore, when the second diode 113 is turned on, the sum of the tension setting value and the first tension compensation value and the second proportional integral amplifier 111 are output to the inverting terminal (-) of the third proportional integral amplifier 112. The deviation value between the actual voltage v-act and the reference voltage v-ref of the payoff reel driving motor 130 is applied. Accordingly, the third proportional integral amplifier 112 outputs the second tension compensation value to the motor drive controller 120 by proportionally integrating the difference between the values input to the inverting terminal (−). The motor driving controller 120 receives the second tension compensation value output from the second tension compensator 110 and increases the tension of the payoff reel 20 to correspond to the value.

On the other hand, when the sum of the tension set value and the first tension compensation value is larger than the difference between the actual voltage v-act and the reference voltage v-ref of the payoff reel driving motor 130, the second diode 113 is used. By maintaining the non-conduction state, the motor driving controller 120 proportionally integrates the difference between the actual voltage and the reference voltage of the payoff reel driving motor 130 to adjust the tension of the payoff reel by the output value.

On the other hand, when the welder 16 is driven and the welder switch 75 is turned on, a negative voltage is applied to the DC motor 92 of the first tension compensation unit 90 by the reset circuit unit 80. That is, the DC motor 92 is driven clockwise by the application of a negative voltage to reduce the tension compensation value to reset the operation of the DC motor driving resistor 93. When the strip 21 is removed from the electrolytic tank 12 when the foreign matter removal operation is completed, the tension value initially set when the welder 16 is operated to weld the end of the strip where the foreign matter removal operation is completed and the tip of the newly supplied strip. In this way, the operation of the driving resistor 93 is reset so that the payoff reel 20 is driven.

4 is a current waveform diagram when a defect occurs in the strip in the electrolytic tank, and FIG. 5 is a current waveform diagram of each circuit unit according to the present invention when a defect occurs in the strip. When the electrode plate and the strip come into contact with the strip by changing the tension of the strip during the debris removal operation of the strip by the electrohydrogenation reaction of the soda solution in the electrolytic tank, as shown in FIG. Will be. At this time, the actual current detection unit 40 detects the current change of the electrode plate 22 as shown in C1 of FIG. 5, and the comparator 60 detects the actual current detection value C1 and the current in the section in which the instantaneous ground current is generated. The set value C2 is compared, and the deviation values C1-C2 are detected and output. Thereafter, the first tension compensator 90 operates the driving resistor 93 based on the deviation value to output the first tension compensation value.

Strip defect prevention apparatus in the electrolytic tank according to the present invention is not limited to the above-described embodiment can be carried out in various modifications within the range allowed by the technical idea of the present invention.

As described above, by detecting a change in the current applied to the electrode plate by the strip defect prevention apparatus in the electrolytic tank according to the present invention, whether the strip defects are easily checked and monitored throughout the entire work process, rather than a sample inspection. It is possible to improve the accuracy of the detection of defect occurrence of the strip and to increase the productivity. In addition, when detecting a defect in the strip, the tension of the payoff reel is automatically increased to prevent the strip from contacting the electrode plate, thereby suppressing the defect rate of the strip as much as possible, thereby preventing deterioration of product quality. You can get it.

Claims (4)

Passing the strip between the two electrode plates while the electrode plate inside the electrolytic tank containing the electrolyte is energized to remove foreign substances on the surface of the strip, and to drive the payoff reel and the payoff reel to maintain the tension applied to the strip A strip control apparatus in an electrolytic tank of an electrolytic cleaning equipment having a pay-off reel motor, A current sensing unit for detecting a change in current applied to the electrode plate; A comparator for comparing the actual detected current value sensed by the current detector with a reference current value set by the user and calculating a difference; A deviation upper limit setting unit configured to set an upper limit on a deviation between the actual current value and the reference current value; A first tension compensator for calculating a tension compensation value proportional to the deviation when the deviation value output from the comparator is greater than an upper deviation limit value; A tension setting unit configured to receive an initial tension value of the payoff reel; The tension set value and the tension compensation value are summed, and the difference between the actual driving voltage and the reference voltage of the pay-off reel motor is obtained, and the pay value is obtained by the final tension compensation value due to the tension set value, the tension compensation value and the motor driving voltage deviation. An apparatus for preventing a strip defect in an electrolytic tank, comprising a second tension compensator for controlling driving of an off-reel motor. The method of claim 1, And a buzzer driver for driving the buzzer when the deviation value outputted from the comparator and the deviation value alarming the occurrence of a defect in the strip is greater than the upper limit deviation value. The method of claim 1, The first tension compensator proportionally integrates a DC motor driving resistor for varying an output voltage in proportion to a deviation value output from the comparator, and an output voltage varying according to the driving of the DC motor driving resistor. An apparatus for preventing strip defects in an electrolytic tank, comprising an amplifier. The method of claim 3, wherein When it is determined that the foreign material removal operation of the strip supplied to the electrolytic tank is completed, a reset circuit unit for resetting the driving of the DC motor driving resistor is further provided to maintain the tension value of the strip at the value set in the tension setting unit. Strip defect prevention device in the electrolytic tank, characterized in that the.