JP2000087274A - Cleaning method and device for magnetic metallic strip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate high frequency oscillation on a magnetic metallic strip such as a steel sheet or the like running in a cleaning soln. and to efficiently clean the magnetic metallic strip. SOLUTION: This device is provided with a pair of DC electromagnets 2 respectively faced to surface and back both faces of a steel strip 1 fed from carrying rolls 6 and 7 arranged being away with each other into a tank 5 stored with a cleaning soln. and running in the cleaning soln., a range finder 3 measuring the position of the steel sheet l, a control device 4 executing the feed back control of the attracting force of the electromagnets 2 in such a manner that the deviation between the measured position of the steel sheet 1 obtd. by the range finder and the objective position is made zero and a tension control device for the magnetic metallic strip not shown in fig., and, moreover, the control device is regulated so as to generate resonance of prescribed frequency on the steel sheet 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cleaning a magnetic metal body, and more particularly to a method and an apparatus for cleaning a magnetic metal body suitable for cleaning a magnetic metal body running in a cleaning solution.

[0002]

2. Description of the Related Art In general, as a method for cleaning a continuously running strip-shaped steel sheet (magnetic metal body), the steel sheet is passed through a tank containing a reactive solution (washing liquid) such as an acid or an alkali. A method of washing by immersion in the solution, a method of generating high-frequency vibrations by ultrasonic waves or the like in a reactive solution further immersed in a steel sheet, and destroying and removing a scale layer and an oil film are known. I have.

However, in the former method, in which the steel sheet is simply immersed in a reactive solution such as an acid or an alkali in a tank, the amount of acid and the like used is increased due to poor cleaning efficiency, and the line speed is increased. However, there is a problem that the cleaning efficiency is poor because of the inability to perform the cleaning, and the latter method of generating high-frequency vibration in the reactive solution has a problem that the cleaning efficiency is not always good.

In order to solve such a problem, a metal product (magnetic metal body) immersed in a reactive solution has been proposed.
In this method, an electromagnet is arranged opposite to a metal product, and an alternating current having the same frequency and a phase shift of π / 2 is supplied to the electromagnet to directly apply high-frequency vibration to the metal product to perform pickling or the like. It has been proposed in Japanese Unexamined Patent Publication No. Hei 5-117883.

[0005]

However, in the method proposed in the above-mentioned publication for supplying an alternating current having the same frequency and a phase shift of π / 2 to the electromagnet, a sufficiently high frequency vibration is applied to the metal product. In order to generate the power, a power supply having a large power supply capacity is required, and there is a problem that power consumption increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and efficiently generates a sufficiently high frequency vibration in a magnetic metal strip running in a cleaning solution and reduces power consumption. An object of the present invention is to provide a method and an apparatus for cleaning a magnetic metal strip which can be performed.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a method for cleaning a magnetic metal strip which vibrates and cleans a magnetic metal strip running in a cleaning solution, wherein a magnetic field is applied to the magnetic metal strip by a DC electromagnet to position the magnetic metal strip. In the feedback control of the above, the above-described problem is solved by generating resonance at a target position in the magnetic metal band and causing the magnetic metal band to vibrate at a high frequency.

The present invention also provides a magnetic metal band cleaning apparatus for cleaning a magnetic metal band running in a cleaning liquid by vibrating the magnetic metal band, comprising: a pair of DC electromagnets opposed to both front and back surfaces of the magnetic metal band; Position measuring means for measuring the position of the magnetic metal band; and a magnetic metal by the DC electromagnet so that the deviation between the measured position of the magnetic metal band obtained by the position measuring means and the target position of the magnetic metal band is zero. A control means for feedback controlling the suction force of the band is provided, and the control means is adjusted so as to generate resonance of a predetermined frequency in the magnetic metal band. It is a solution.

The present inventors have set out to solve the above problems.
As a result of various studies, it was found that DC electromagnets were disposed on both sides of a steel plate (magnetic metal body) so as to face each other, and the magnetic metal body was feedback-controlled to a target position by the electromagnet, whereby vibration generated in the steel plate was obtained. In a vibration damping device that controls vibration in a non-contact manner, the control amount (in this case, the position in the thickness direction of the magnetic metal body) can be adjusted around the target value by appropriately selecting the control gain so as to balance with the tension applied to the steel sheet. By periodically changing the so-called resonance, it is evident that relatively high-frequency vibrations are continuously generated in the steel sheet, that is, there is a resonance limit,
In addition, it has been found that the frequency of the vibration is about 20 to 100, which is sufficient to promote the cleaning of the steel sheet. Therefore, in the present invention, high-frequency vibration means vibration at a frequency of about 20 to 100 Hz.

The present invention has been made based on this finding. For example, a pair of DC electromagnets disposed opposite to the front and back surfaces of a magnetic metal strip running in a cleaning solution, and the position of the magnetic metal body From a position measuring means for detecting the distance between the electromagnet and the magnetic metal body based on a position signal from the measuring means to form a feedback control system for controlling the distance to a target value by the attractive force of the DC electromagnet, By controlling at a resonance limit of the control system, high-frequency vibration is applied to the magnetic metal body, and the metal body itself is cleaned while being vibrated, so that cleaning efficiency can be improved.

In the control method using the feedback control system, PID (proportional / integral / differential) control is basically sufficient. In this case, the control condition of the resonance limit is, for example, by gradually increasing the proportional gain Kp. The point at which the vibration continues is the condition. However, since the conditions differ depending on the thickness and width of the magnetic metal strip and the tension of the line as described later, it is necessary to obtain the conditions in advance for each condition. By controlling at the resonance limit of the control system determined in this way, it becomes possible to apply high-frequency vibration to the magnetic metal band.

Since a DC electromagnet is used in the present invention, the power source is a voltage of 100 V and a current of 1 to 3 A.
Is enough. In the conventional method of supplying an alternating current with a phase shift of π / 2, the voltage is 200 to 400 V and the current is 10 to
20A is required. The power consumption can be reduced to about 1/20.

Therefore, cleaning with high efficiency and low power consumption can be performed.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a main configuration of a cleaning apparatus according to an embodiment of the present invention.

As shown by the arrows, the cleaning device of the present embodiment comprises a pair of DC electromagnets 2 disposed opposite to both front and back surfaces of a steel plate (magnetic metal strip) 1 traveling in the horizontal direction.
And a distance meter (position measuring means) 3 for measuring the distance (position of the steel plate) to the front surface or the back surface of the traveling steel plate 1, a distance (measured position) actually measured by the distance meter 3, and a target value (target) Position) so that the deviation from the position
(Control means) 4 for outputting a control command signal for feedback-controlling the attraction force on steel sheet 1 by means of
And

As shown in FIG. 2, the cleaning apparatus includes a cleaning tank 5 in which a cleaning liquid comprising a reactive solution such as an acid or an alkali is stored. By being transported in the direction of the arrow by the transport rolls 6 and 7 arranged in the vertical direction, it travels in the cleaning liquid.

Inside the washing tank 5, airtight cases 8 are disposed at upper and lower positions sandwiching the steel sheet 1 fed by the rolls 6 and 7, respectively. A distance meter 3 is accommodated so as not to touch the cleaning liquid. In this figure, for convenience, the steel plate 1 is
Although it is shown as penetrating through the wall portion, the cleaning liquid actually enters the cleaning liquid upstream of the roll 6 and exits the liquid downstream of the roll 7.

The tension of the steel plate 1 is controlled by tension control means (not shown) installed upstream and downstream of the cleaning device. Generally, a bridle roll is used as the tension control means, and the control is performed while monitoring the tension with a tension measurement roll or the like.

FIG. 3 is a control block diagram of the cleaning apparatus. This control block diagram shows a vibration control device which has been proposed by the present applicant in Japanese Patent Application Laid-Open No. 9-184055 for the purpose of suppressing vibration of the steel plate 1 and controlling the steel plate 1 to a target position. Is substantially the same as

That is, in the cleaning device of the present embodiment, the measured value of the distance meter 3 is compared with a preset target value, and when the deviation is input to the control device 4, it is reduced to zero. The driving force is output to the electromagnet 2 via the driving device 10 (omitted in FIGS. 1 and 2).

In the control device 4, the proportional element 41 and the integrating element 42 are connected in parallel, and a high-frequency phase lead compensating element 43 is connected in series downstream of the proportional element 41 and the integrating element 42 so as to compensate for the response delay of the electromagnet 2. , Phase lead compensation is performed. The high-frequency phase lead compensation element 43 is configured to perform third-order phase lead compensation as represented by a transfer function. However, first-order, second-order, and fourth-order or higher compensation may be performed.

When a vibration control is to be performed by the cleaning device, a deviation between a target value A and an actually measured value C of the displacement B of the steel plate 1 by the distance meter 3 is input into the control device 4. A drive control signal is calculated, and the signal is input to the electromagnet 2 via the drive control device 10 as an output.
Can be performed by feedback control for controlling the position of the target to the target position.

In this embodiment, when performing the same control as the feedback control, the control device 4 shown in FIG.
Is applied to the steel plate 1 at a predetermined frequency, for example, 20 to 100H.
At a frequency of z, it is adjusted to generate resonance oscillating with an amplitude of 1 to 10 mm.

More specifically, when the feedback control system of the vibration suppression control controls the steel sheet 1 to the target position, the control gain is a control gain that multiplies the deviation between the actually measured position of the steel sheet 1 and the target position. The resonance is generated by adjusting the proportional gain Kp shown in FIG.

FIG. 4 shows the cleaning apparatus of this embodiment,
The characteristic of the control gain adjusted by the control device 4 when the resonance is generated is conceptually shown in comparison with the control gain in the case of the conventional vibration suppression control.

In FIG. 4, the solid line corresponds to the case where the tension is high, the dashed line corresponds to the case where the tension is low, A and B indicate the resonance generating regions in each case, and C and D indicate the preferable ranges. It represents.

As can be seen from the graph, in order to generate the resonance, a gain applied to the vibration suppression control (a vibration suppression control area in the figure)
It is understood that adjusting the control gain to a higher value than that of the above is suitable for a wide control range. However, if the control gain is too high, the vibration becomes excessive.
There is a suitable range for making the amplitude of mm, for example, it is effective to make the gain about twice that in the case of vibration suppression control.

In the present embodiment, the vibration of the steel sheet 1 due to the resonance occurs between the transport rolls 6 and 7, and
Since this is the next mode of vibration (vibration at the natural frequency), the frequency does not change so much if the dimension of the steel sheet 1 and the distance L between the rolls are fixed, but the frequency does not change much. Change related.

FIG. 5 conceptually shows the relationship between frequency and tension for steel sheets having different dimensions (steel strip dimensions 1 and 2 in the figure).

As shown in this figure, since the frequency due to the resonance slightly depends on the tension, in order to generate the resonance at a predetermined frequency, the control gain is set in consideration of the tension applied to the steel plate 1. Need to adjust.

Further, depending on the value of the control gain, if the tension is low, the vibration diverges (excessive amplitude). Therefore, there is a suitable range of the control gain according to the tension for each steel sheet of each size.

As described in detail above, in this embodiment, the magnetic field is applied to both the front and back surfaces of the steel
A high frequency vibration is applied to the steel sheet 1 by intentionally generating resonance by using a vibration damping device that suppresses vibration of the steel sheet and adjusting the gain of the feedback control system to a higher value (forced vibration is applied). ) Together with the tension so that the vibration does not diverge, thereby generating continuous vibration.

At this time, the cleaning device and the tension control device may be managed by a higher-level control device, and the tension and the vibration condition for obtaining the appropriate vibration condition (frequency and amplitude) may be set.

Therefore, according to the present embodiment, the distance between the DC electromagnet 2 and the steel plate 1 (the position of the steel plate 1) is determined based on the distance signal input from the distance meter 3. A high-frequency vibration is generated in the steel sheet 1 by controlling a resonance limit of the control system to form a feedback control system for controlling a constant (target position) by the suction force so that the steel sheet itself is vibrated for cleaning. As a result, cleaning can be performed efficiently and with low power consumption.

Although the present invention has been described in detail, the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the gist thereof.

For example, the specific configuration of the control system of the cleaning apparatus applicable to the present invention is not limited to that shown in the control block diagram of FIG.

Although a steel plate is taken as an example, it goes without saying that the present invention in which resonance is generated by applying a magnetic field can be applied to a magnetic metal band.

Further, in the above-described embodiment, pickling or alkali washing has been described as a specific example, but it is needless to say that the present invention may be applied to washing using another washing liquid such as a surfactant.

[0040]

As described above, according to the present invention,
A high frequency vibration having a sufficient height can be efficiently generated in the magnetic metal strip running in the cleaning liquid with about 1/20 of the power consumption of the conventional one, and the magnetic metal strip can be efficiently cleaned.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of a cleaning apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a schematic configuration of the cleaning device.

FIG. 3 is a control block diagram of the cleaning device.

FIG. 4 is a diagram showing a relationship between a gain during vibration suppression control and a gain during vibration control.

FIG. 5 is a diagram showing a relationship between tension and frequency during vibration control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Steel plate 2 ... DC electromagnet 3 ... Distance meter 4 ... Control device 5 ... Cleaning tank 6, 7 ... Transport roll 8 ... Case 10 ... Drive device 41 ... Proportional element 42 ... Integral element 43 ... Phase advance compensation element A ... Target value B: Displacement C: Actual measured distance

Continuation of the front page F term (reference) 3B201 AA08 AB16 AB37 AB47 BB02 BB92 BB94 BB95 BC05 CB01 CD42 CD43 4K053 PA02 PA12 QA01 QA04 SA06 TA16 XA09 YA22 YA24 5D107 AA03 BB11 CC09 CD05 CD10 DE01

Claims (4)

[Claims] 1. A method for cleaning a magnetic metal strip which vibrates and cleans a magnetic metal strip running in a cleaning liquid, wherein a magnetic field is applied to the magnetic metal strip by a DC electromagnet and the position of the magnetic metal strip is feedback-controlled. A method for cleaning a magnetic metal band, comprising: generating a resonance with respect to a target position in the band and causing the magnetic metal band to vibrate at a high frequency. 2. The magnetic metal strip according to claim 1, wherein when controlling the magnetic metal strip to a target position, a control gain that multiplies a deviation between an actual measurement position of the magnetic metal strip and the target position is applied to the magnetic metal strip. A method for cleaning a magnetic metal strip, comprising adjusting the tension according to the tension to generate the resonance. 3. A magnetic metal band cleaning apparatus for cleaning a magnetic metal band running in a cleaning liquid by vibrating the magnetic metal band, comprising: a pair of DC electromagnets facing both front and back surfaces of the magnetic metal band; Position measuring means for measuring the position, and the attractive force of the magnetic metal band by the DC electromagnet so that the deviation between the actual measured position of the magnetic metal band obtained by the position measuring means and the target position of the magnetic metal band is made zero. And a control means for performing feedback control on the magnetic metal strip, and the control means is adjusted so as to generate resonance of a predetermined frequency in the magnetic metal strip. 4. The apparatus according to claim 3, wherein the control means adjusts a control gain by which a deviation between an actual measured position of the magnetic metal band and a target position is multiplied when controlling the magnetic metal band to a target position. An apparatus for cleaning a magnetic metal strip, wherein the apparatus generates the resonance.