JPH04110499A - Method and device for controlling stray current - Google Patents

Abstract

PURPOSE:To easily and automatically control generation of stray current by impressing electrical potential polarity reverse to the electrical potential polarity in the part when stray current flow to the part of a metallic strip nearer to an electrolytic treatment device from an instrument while utilizing an outer-part power source. CONSTITUTION:Firstly while continuously passing a metallic strip 19 as an ordinary method, this metallic strip is electrolytically treated in an electrolytic treatment device in a working treatment line. The electric potential difference between contacts 17, 17 and the electric potential polarity are detected by an amplifier 22 for detecting stray electric potential difference and inputted to the amplifier 11 for controlling external power source voltage. While continuously detecting this electric potential difference and electric potential polarity, the voltage of a voltage variable type external power source 10 is controlled so that these are regulated or reached to zero. This means that stray current 13 conducted via the metallic strip 19 located outside the an electric potential difference detection point from the electrolytic treatment device among the stray current routes is regulated or reached to zero. Accordingly the stray current 13 is regulated to zero or reduced to almost zero and eliminated. This stray current 13 flows through a metallic roll 2 and a shear 3 that are located outside the electric potential difference detection point.

Description

[Detailed Description of the Invention] [Industry - Second Field of Application] The present invention is directed to a series of processing lines equipped with equipment that continuously performs electrolytic treatments such as plating and descaling on metal strips. The present invention relates to a stray current suppressing method and device capable of suppressing the stray current that occurs and preventing damage caused by the stray current to metal strips and various devices and equipment inside the processing line.

[Conventional technology]

Conventionally, in electrolytic treatment equipment consisting only of negative tanks, the city electrode and negative electrode are arranged symmetrically in the same tank.
The potential difference in the metal band between the inlet and outlet sides of the tank was extremely small, so that almost no current (this is called a stray current) flowing other than the original energization path was generated.

In addition, even if the device is configured with two tanks, there is a large potential difference between the person in the tank and the metal band between the exit side due to the electrode arrangement, and the electrolytic treatment equipment is configured with multiple tanks and there is a large potential difference between the person in the tank and the metal band between the exit side. In processing lines equipped with electrolytic treatment equipment that generates a large potential difference between the strips, the generation of stray current can be avoided by electrically insulating the metal strip and the equipment that passes the metal strip with an insulating material (such as rubber). was preventing.

However, if an existing processing line has a threading device that is not electrically insulated from the metal strip, it is difficult to find a line that has a threading device that is not electrically insulated from the metal strip.
When a device has an electrolytic treatment device with a large potential difference between the metal strips between the output sides or is additionally installed, it is not possible to prevent the generation of stray currents, resulting in the following problems.

(A) When a metal strip is sheared by a shear installed in the processing line, sparks are generated between the shear and the metal strip, causing damage to the metal strip, chipping of the shear blade, and abnormal shearing of the metal strip. etc. are produced.

(a) Sparks generated between the surface of the metal roll installed in this line and the metal strip cause spatter to adhere to the opening surface, and the spatter causes indentation scratches on the metal strip.

(1) Electric current flows through the metal roll bearings, causing the hair rings to seize.

(1) For reasons related to sheet threading operations, when an operator inserts a metal rod between the metal band and the sheet threading equipment, sparks are generated and the operator may get burned.

[Problem to be solved by the invention]

In order to solve the above-mentioned problems of the prior art, the present invention easily and automatically suppresses the generation of stray current in a series of processing lines having equipment for continuously electrolytically treating metal strips. The objective is to prevent damage to the metal strip and the various devices and equipment inside the processing line caused by the current, and to stably protect the metal strip and the processing line.

[Failure to solve the problem]

The present inventors have discovered that due to the path through which stray currents flow outside the electrolytic treatment equipment, damage caused by stray currents can occur not only to the metal strip but also to devices such as unwinding devices, winding devices, and metal rolls and shears for threading. As a result of investigating the location of the equipment where the stray current actually occurs or has the potential to occur, and making various considerations, we found that when a stray current is flowing in the metal strip that is closer to the electrolytic treatment 11 equipment than the equipment, the stray current ( The generation of stray current can be easily and automatically suppressed by constantly applying a voltage with the opposite potential polarity to the electrolytic power source of the electrolytic treatment equipment using an external power source that is different from the electrolytic power source. The present invention was completed through investigation.

The electrolytic treatment device referred to in the present invention includes a plating device and a descaling device, and the device may include only one tank or multiple tanks. The present invention will be explained below by taking a processing line having a two-tank descaling electrolytic treatment device as an example and comparing it with a case where the present invention is not applied.
The present invention is similarly applicable even when other electrolytic treatment equipment is provided or additionally installed.

Fig. 1 is a schematic configuration diagram of an example in which the device of the present invention is applied to an electrolytic treatment line, Fig. 2 is a simplified equivalent circuit diagram of Fig. 1,
FIG. 3 is an explanatory diagram of the path of stray current when electrolytic treatment is performed without applying the present invention in FIG. 1, and FIG. 4 is a simplified equivalent circuit diagram of FIG. 3.

The processing line shown in Figures 1 and 3 is a descaling line that has a two-tank electrolytic treatment device for descaling, and only the main devices and equipment are shown in the diagram.The operating status is as follows. It seems like. The metal strip 19 unwound from the unwinding device 1 is driven by a metal roll 2 for threading, runs continuously, passes through the inlet electrolytic treatment device 5 and the outlet electrolytic treatment device 6, and is again used for threading. winding device 4 via the metal roll 2
1, the inlet electrolytic treatment device 5, and the outlet electrolytic treatment bag w6 are each provided with a positive electrode 7 and a negative electrode 8 facing the surface of the metal band 19, and the voltages ■, Lightning current electric Mff! When the metal strip 19 passes through each electrolytic treatment device 5, 6 containing an electrolytic solution, the metal strip 19 is connected to a power source 9 (generally of a variable current type to adjust the input power amount), and is connected to each electrode 7, 8 when the metal strip 19 passes through each electrolytic treatment device 5, 6 containing an electrolytic solution. The opposing locations are each polarized into a negative electrode and an anode, forming a circuit, and an electrolytic current 12 shown by a dashed line in the direction shown in the figure flows. Descaling treatment is carried out under the action of electrolysis and anodic electrolysis, and the material is wound up by a winding device 4 while being cut by a winder 3 at appropriate locations.

In such electrolytic treatment, the original electrolytic current 12 is as described above (electrolytic power source 9) → positive electrode 7 → metal strip 19 →
The current flows through the current path from the negative electrode 8 to the (electrolytic power source 9). However, in the processing line, for example, people from electrolytic processing equipment,
Devices and equipment that have parts that constantly come into contact with the metal strip 19, such as the metal roll 2 for sheet threading on the exit side, the unwinding device 12 and the winding device 4, and the metal strip 19 when necessary, such as the shear 3, etc. Equipment and equipment that have parts that may come into contact with the earth are installed, and these are electrically connected to the ground with low electrical resistance by means of a supporting frame or pedestal, either directly or through the earth. There is a state in which a number of stray current paths 13, such as those shown by the two-dot chain line in FIG. 3, having the electrolytic power source 9 as a starting point and ending point, can be formed in addition to the original current conducting path, that is, the electrolytic current 12. Therefore, if the potential difference between the positive electrode 7 and the negative electrode 8 is too large, the stray current 13 in the current path direction shown in FIG. 9
)→Anode 7→Metal band 19→Metal roll 2→Frame.

Frame, ground → metal roll 2 → metal strip 19 → negative electrode 8 → (
Like an electrolytic power supply 9), or instead of or in addition to the metal roll 2, it flows through the unwinding device 1 or the winding device 4. Furthermore, when the shear 3 operates to shear the metal strip 19, the shear 3 can also become a path for the stray current 13. The path and magnitude of this stray current 13 depend on differences in the metal strip itself (metal type, steel type, two dimensions, etc.), differences in electrolytic treatment equipment and processing lines that include it, etc.
Differences in configuration within processing lines that consist of various devices and equipment, differences in grounding and insulation between component devices and equipment and the entire processing line, and electrolytic processing conditions (threading speed, metal strip, etc.) electrolytic current density to.

It changes depending on the concentration and temperature of the electrolytic treatment solution, the temperature of the metal band, etc.) and various operating conditions. Such stray current 1
FIG. 4 shows a simplified equivalent circuit of No. 3. The photocurrent 20 (1) that flows from the electrolytic power source 9 and receives a line resistance of 1.4 (RLl) is caused by the resistance of the metal band between the negative and positive polarizations at point A (corresponding to the upstream end of the positive electrode 7). 1.5 (Rst)
electrolytic current] 2 (I□) and stray path resistance 16 (R
It splits into stray current 1.3 (12) that receives A), merges at point B (corresponding to the downstream end of cathode 8), receives circuit resistance 1.4 (RL2) again, and becomes electrolytic current 9. return. The magnitude of this stray current 1.3 (12) is ``I2=RA'' where ``■'' is the potential difference between the input and output sides of the electrolytic treatment apparatus, that is, the potential difference between points A and B. The present invention aims to bring this potential difference v'' between points A and B close to zero, that is, to prevent it from disappearing.

That is, the present invention provides an electrolytic treatment apparatus in which electricity is indirectly applied from an electrolytic power supply through an electrode placed opposite to the metal strip along the length direction thereof, and a metal strip to be threaded. The metal strip is continuously passed through a processing line where devices and equipment with parts that are in constant contact and/or may come into contact are installed, and the metal strip on the exit side of the electrolytic treatment equipment and the metal strip on the exit side and 1. When performing electrolytic treatment that involves the generation of stray current in which equipment or equipment is part of the current path, the electrolytic treatment equipment or equipment that is part of the current path is The potential difference detection points of the metal strip are set at positions close to the processing equipment, and the potential difference between both detection points of the metal strip and the potential polarity thereof are continuously detected, and the potential difference between the two detection points of the metal strip and the potential polarity are continuously detected. A voltage that is controlled to be almost the same with a potential polarity opposite to that detected at the one detection point is constantly applied from an external power source different from the electrolytic power source to detect the potential difference between the two detection points of the metal strip. This is a stray current suppression method characterized by suppressing the generation of stray current by reducing.

]1 Another aspect of the present invention is an electrolytic treatment apparatus in which electricity is indirectly applied from an electrolytic power source through an electrode arranged opposite to the metal strip along the length direction of the metal strip to be threaded, and The metal strip is continuously passed through a processing line where devices and equipment that have parts that constantly and/or may come into contact with the metal strip are installed. A device for suppressing the generation of stray current in the case of electrolytic treatment accompanied by the generation of stray current in which the metal band and the device or equipment are part of the current path, the device comprising: (1) a line upstream side of the electrolytic treatment device; and a contactor for detecting a potential difference that is installed so as to be able to be contacted at all times at a potential difference detection point of a metal band that is set at a position closer to the electrolytic treatment equipment than devices or equipment that should be protected from stray current on the downstream side; (2) A stray line potential difference detector consisting of an amplifier for detecting a stray line potential difference that continuously detects the potential difference and potential polarity between the two detection points; (5) a power source different from the electrolytic power source and capable of voltage control; an external power source, (d) a power supply device installed in the vicinity of either one of the surface potential difference detection points so as to be able to contact the metal band, and (il) a potential difference detected by a detector having the stray line potential difference detection amplifier. and an external power supply voltage control amplifier that takes the potential polarity as an input signal and outputs a potential control signal to the external power supply to bring these potentials close to zero, that is, to erase them, and detects the potential difference on the side where the power supply device is installed. The terminal of the external power supply with the opposite potential polarity to the point is connected to the power supply device, and the other terminal of the external power supply has the same potential polarity as the other terminal of the electrode of the electrolytic power supply of the electrolytic treatment equipment. The stray current suppressing device is characterized in that the stray current suppressing device is connected to the electrode closest to the power supply device.

The principle of the present invention will be explained using the simplified equivalent circuit diagram shown in FIG. In the present invention, a circuit having an external power source 10 is provided between a selected zero point (corresponding to the position of a power supply device 8 to be described later) on the stray conductor and an electrolytic power source 9. The line resistance 1.6 (RA) of the stray line in Figure 4 is divided into the line resistance 16''(RA') and the resistance 15'(Rst') of the metal strip 13 at the 0 point in Figure 2, The resistor 14' (RL3) is connected to the external power supply 10 so as to apply a voltage V' to the point C that is opposite to the potential polarity of the electrolytic power supply 9 at the point C. When it is assumed that there is no circuit including the external power supply 10, the stray current 1.3 (1,) is almost the same as in Fig. 4, and the stray current 1.3 (1,) at point A, stray line resistance ]6'(RA') ,
It returns to the electrolytic power source 9 through point C, metal band resistor 15'(Rst'), and 8 points in sequence. However, when the external power supply 1.0 is activated and a voltage of opposite potential polarity is applied to point C, the stray current suppression current 21 (1,) flows in the direction of the arrow as shown in FIG. The potential difference between them becomes smaller, and therefore the stray current 1.3 (12) becomes smaller accordingly. An inverse voltage V' applied from the external power supply 1o to the point C of the metal band 19 is controlled by the potential control signal output from the external power supply voltage control amplifier] to make the potential difference between the points A and C zero. The closer the stray current 13 (12) is brought to zero, the smaller the magnitude of the stray current 13 (12) becomes, until it can be completely erased.

The device of the present invention is a more concrete configuration of the above principle.

〔Example〕

The apparatus of the present invention will be specifically explained with reference to the embodiment shown in FIG.

When setting the potential difference detection points of metal bands on both sides of the inlet and outlet (same upstream and downstream of the line) of the electrolytic treatment equipment 5 and 6, protect the input or outlet side from stray current 13. Determine the equipment and equipment that should be used by investigating the actual situation and making predictions.

If a plurality of such devices or devices are present, they are included in the area requiring stray current reduction. In this example, the devices that should be protected from the stray current 13 are the metal roll 2 and shear 3. Therefore, in this example, as shown in FIG.
Potential difference detection points are set respectively, and potential difference detection contacts 17.1.7 are set at the positions of both detection points as shown in Fig. 1.
Stray line potential difference detection which detects and outputs the potential difference as well as the potential polarity between the two detection points based on the input signal]5 An output amplifier 22 is installed. In this case, if there is no particular device or equipment that should be protected from stray current 13, both detection points are set at the positions closest to both sides of the electrolytic treatment equipment 5 and 6, and Potential difference detection contact 1
7. ], 7 may be installed. Then, any one of the potential difference detection points 1.
7. A power supply device 18, such as a contact type metal power supply roll, is installed near one of the points 7.1.7. Generally, if the power supply system [118 is installed close to the electrolytic treatment equipment 5, 6, the section in which stray currents are suppressed can be lengthened, but the external power supply 10 for suppressing stray currents must have a large capacity. shall be. Conversely, if the power supply device 18 is mounted far away from the electrolytic treatment devices 5 and 6, the external power source 10 may have a small capacity, but the section in which stray current is suppressed will be shortened. Overall, it is preferable that the position be closer to the electrolytic treatment device than the device or device that requires the reduction of the stray current 13 passing therethrough. Further, there is no limitation as to whether the position is near the potential difference detection contact 17, 1.7 on either the second or downstream side of the line, but from the above point of view, it is preferable that the distance from the electrolytic treatment apparatus be long. In this example, the potential difference detection contact 7 on the downstream side of the line is selected. If the potential difference detection contact 7 on the upstream side of the line is selected, the potential polarity of the applied voltage will be opposite to the potential polarity in this example, which will be described later.

Also, an electrolytic power source voltage detector 23 for detecting the voltage of the electrolytic power source 9. External power supply IO and external power supply voltage control amplifier]]
Set up each. This external power supply voltage control amplifier]
1 is preferably of a proportional/integral type so as to eliminate offset, and an external potential control signal that reduces, improves, or eliminates the potential difference detected and output by the stray line potential difference detection amplifier 22 and its potential polarity is preferably used. The power source 10 outputs the signal.

In addition, the reason why the electrolytic type g voltage detected by the electrolytic power source voltage detector 23 is input to this external power source voltage control amplifier is because the potential difference detected by the stray line potential difference detecting amplifier 22 is input to this electrolytic power source. Since it is close to the value of voltage (■), even if the stray conductor potential difference detection amplifier 22 fails and the detected potential difference becomes unstable, it can become a stable reference voltage that prevents the control system from instantly becoming abnormal. It is from.

1. Wire and connect each device and 2 devices as follows. Therefore, in this example, the power supply device 18 is configured so that the voltage difference detection point on the side where it is installed (therefore, on the downstream side of the line in this example) has an opposite potential polarity and is applied with approximately the same amount of voltage by the external power source 10. As shown in FIG. 1, the wire is connected to the positive terminal (10 terminals) of the external power source 10, and the other terminal, that is, the negative terminal (1 terminal) of the external power source 10 is connected to the external power source 10 of the electrolytic power sources 9 of the electrolytic treatment apparatuses 5, 6. It is wired and connected to the electrode that has the same potential polarity as the terminal on the above side, that is, the negative electrode, and is closest to the power supply device w18 (in this example, for simplicity, it is one negative electrode). The stray line potential difference detection amplifier 22 is configured to manually send the detection signal to the external power supply voltage control amplifier 11, and the electrolytic power supply voltage detector 23 is also connected to the
? [! Connect so that the detection signal (voltage) can be taken out from the source 9 and inputted to the external power supply voltage control amplifier 111.
The output (potential control signal) from the external power supply voltage control amplifier 11 is wired and connected so that it can be input to the external type g (10).In this way, the device of the present invention is configured as shown in FIG. It is.

Next, the case where the method of the present invention is implemented using each of the above-mentioned devices and equipment will be explained along with their effects.

First, a metal strip 19 within an acceptable range of metal type, steel type, two dimensions, etc. is electrolytically treated in an electrolytic treatment device in a processing line while being passed continuously as usual. Since the potential difference between the contacts 17 and 1.7 and its potential polarity are detected by the stray line potential difference detection amplifier 22 and input to the external power supply voltage control amplifier 11, this potential difference and its potential polarity are continuously detected. While detecting these, the voltage of the variable voltage external power supply 10 is controlled so that these values approach zero or 1-J. As described above, this external power source 10 applies a voltage to the power supply device J8 that is opposite to the potential polarity of the electrolytic current 12 generated by the electrolytic power source 9 at the potential difference detection point (at the same position as the contact 17°]7). Therefore, as described above, the potential difference between the contacts 1.7.1.7 and the potential polarity thereof can be brought to zero or close to zero, that is, can be erased. The method of the present invention capable of producing such an erasing effect is automatically carried out by the apparatus of the present invention as explained with reference to FIG.

By carrying out the method of the present invention, the potential difference between the potential difference detection points can be brought to zero or close to zero. That is, in the stray current path, two metal bands 19 located outside the potential difference detection points from the electrolytic treatment device are removed. It means that the stray current 13 flowing through the metal roll 2 or the shear 3 that is located outside the potential difference detection point is reduced to zero or close to zero.
can be reduced to zero or close to zero and even eliminated.

Furthermore, even if for some reason the signal of the potential difference between the contacts 1, 7, 1, 7 does not enter the external power supply voltage control amplifier 1, the voltage of the electrolytic power supply 9 is detected by the electrolytic power supply voltage detector 23. By inputting these information, it is possible to take countermeasures without immediately causing abnormal operation.

〔Effect of the invention〕

As described in detail above, the present invention is equipped with an electrolytic treatment apparatus that has a large metal charge potential difference between the electrolytic treatment apparatus and the output side, and in which the metal band passing device and the metal band are electrically insulated. Equipment that is not installed 1. In the continuous processing of two metal strips,
By configuring the external power supply to apply a voltage opposite to the potential polarity when a stray current is flowing to a part of the metal strip that is closer to the electrolytic treatment equipment than the equipment or equipment that should be protected from stray current, the following can be achieved. It has the effects described in .

(j) The generation of stray current within a series of processing lines can be easily and automatically suppressed.

This can bring about the following effects.

(ii) When shearing a metal strip with a shear, it prevents sparks from occurring between the metal strips and prevents damage to the metal strip itself.
Prevents blade chipping of shear knives, shearing abnormalities of metal bands, etc.

(Ii) There are no small sparks generated between the surface of the metal roll and the metal strip, and the spatter attached to the roll does not cause scratches on the surface of the metal strip.

(i) No current flows through the metal roll bearings, preventing the bearings from seizing up.

, γ (V) Even if a metal rod is inserted between the metal band and the threading device, no sparks are generated and there is no effect on the human body.

(≠) In this way, it is possible to protect and stably maintain not only the metal strip itself that is continuously threaded, but also the processing line, which consists of various devices and equipment other than the electrolytic treatment equipment, and improve the quality and quality of the metal strip. Improved retaining surface.

It is extremely effective in improving the efficiency and productivity of optical processing lines and reducing maintenance costs.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of an example in which the device of the present invention is applied to an electrolytic treatment line, Fig. 2 is a simplified equivalent circuit diagram of Fig. 1,
FIG. 3 is an explanatory diagram of the path of stray current when electrolytic treatment is performed without applying the present invention in FIG. 1, and FIG. 4 is a simplified equivalent circuit diagram of FIG. 3. In the drawings 1... Unwinding device 2... Metal roll for threading 3... Shear 4... Winding device 5... Entry side electrolytic treatment device 6... Output Side electrolytic treatment device 7... Positive electrode 8... Negative electrode 9... Electrolytic power source 10... External power source 11... External power source voltage control amplifier 12... Electrolytic current'' 3... ...Stray current 14, 14'...Circuit resistance 15.1.5''...Metal band resistance 1.6.1.6'...Stray current line resistance 17...
Contactor 18 for potential difference detection...Power supply device 19...Metal band 20...Photocurrent 21...Stray current suppression current 22...Amplifier for potential difference detection 23... Electrolytic power supply voltage detector I□t I2+ 13...Current 2:3=RA, RA'...Stray current resistance R150, RL7. RL3...Circuit resistance Rst,
Rst'...Metal band resistance

Claims (1)

[Scope of Claims] 1. An electrolytic treatment device and a metal strip (19) that is indirectly energized from an electrolytic power source (9) through an electrode placed opposite the metal strip (19) along its length. Metal band (19
) The metal strip (19) is continuously passed through a processing line where devices and equipment that have parts that are in constant contact with the electrolytic treatment equipment and/or parts that may come into contact with the electrolytic treatment equipment are installed. When carrying out electrolytic treatment accompanied by the generation of stray current (13) in which the metal strip (19) and the above devices and equipment are part of the current path, stray current (13) is generated on the upstream and downstream sides of the line of the electrolytic treatment equipment. Place a metal band (19
) to continuously detect the potential difference between the two detection points on the metal band (19) and its potential polarity, and detect the potential difference in the vicinity of either of the two detection points. Electrolytic power source (9)
The metal band (
19) A method for suppressing stray current, characterized in that generation of the stray current (13) is suppressed by reducing the potential difference between the two detection points. 2. An electrolytic treatment device that is indirectly energized from an electrolytic power source (9) through an electrode placed opposite the metal strip (19) along the length thereof, and a metal strip (19) to be threaded.
) The metal strip (19) is continuously passed through a processing line where devices and equipment that have parts that are in constant contact with the electrolytic treatment equipment and/or parts that may come into contact with the electrolytic treatment equipment are installed. A device for suppressing the generation of the stray current (13) when performing electrolytic treatment accompanied by the generation of the stray current (13) in which the metal band (19) and the device or equipment are part of the current path, (i) A metal band (19) set at a position closer to the electrolytic treatment equipment than the equipment or equipment that should be protected from stray current (13) on the upstream and downstream sides of the electrolytic treatment equipment line.
contacts (17), (17) for potential difference detection which are installed so as to be able to be contacted at all times at the respective potential difference detection points; and stray line potential difference detection which continuously detects the potential difference between the two detection points and the potential polarity thereof. (ii) an external power source (10) which is a power source different from the electrolytic power source (9) and whose voltage can be controlled; (iii) either of the two potential difference detection points. A power supply device (18) installed near one side so as to be able to contact the metal band (19)
(iv) Using the electrolytic power supply voltage detected by the electrolytic power supply voltage detector (23), the potential difference detected by the stray line potential difference detection amplifier (22), and its potential polarity as input signals, the stray line potential difference detection amplifier is An external power supply voltage control amplifier (1
1), and the power supply device (18) is connected to the terminal of the external power supply (10), which has the opposite potential polarity to the potential difference detection point on the side where the power supply device (18) is installed. 1
0) is connected to the electrode of the electrolytic power source (9) of the electrolytic treatment device (5, 6) that has the same potential polarity as the other terminal and is closest to the power supply device (18). Features a stray current suppression device.