JPS6115956B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an abnormal current detection device in metal electrolytic refining. When electrolytically refining metals such as copper, zinc, and lead, a tree may grow on the electrode plate and cause a short circuit between the anode and the cathode.
The short-circuit current that flows at this time does not contribute to the precipitation of the target metal and is the biggest cause of lowering current efficiency. Moreover, the short circuit current has a large current value, which causes the electrode plate of the anode to collapse, increases the concentration of impurities in the electrolyte, and deteriorates the quality of the deposited metal, and also generates a large amount of Joule heat. As a result, the load on the cooler increases in order to maintain the temperature of the electrolyte. Therefore, preventing such short circuits in the electrolytic refining process of nonferrous metals is an essential requirement for improving the performance of the electrolytic refining process. In order to cope with this problem, various detection means have been proposed for manually or automatically detecting the magnitude of the current flowing through the electrode plate. These detection means can basically be classified into three methods: (1) inter-pole voltage measurement method, (2) temperature detection method, and (3) magnetic flux measurement method. Among these, according to the interelectrode voltage measurement method, the interelectrode voltage between the anode and cathode electrode plates changes depending on the elapsed time of electrolysis, and there is also a slight voltage change between the shorted electrode plate and the normal electrode plate. Although this voltage change occurs, other factors such as contact resistance during measurement have a large influence, so it is difficult to reliably detect a short circuit state. In addition, in the temperature detection method, not only does it take some time for a short circuit to occur and this short circuit state thermally appears on the electrode plate surface, but also the relationship between the electrode plate temperature and the short circuit current value is weak. Discrimination regarding short circuits is extremely difficult. On the other hand, magnetic flux measurement methods include a method using a current distribution meter and a method using a magnetometer. Among these, a current distribution meter is an instrument that generates torque using a magnetic field generated by a current flowing through an electrode plate, and directly reads this torque on a current scale. In the case of this method using an ammeter, the current value of each electrode plate (usually a cathode plate, the same applies hereinafter) is measured manually, and the electrode plate that shows a value greater than a predetermined current value is connected to a short circuit plate, and the current value is set to a predetermined current value. Electrode plates exhibiting values less than 1 are treated as poor contact plates and the respective causes are eliminated. However, the work of measuring the current value for each electrode plate is not only complicated, but also the work itself is inefficient, especially since all the work is done manually. Furthermore, there are magnetometers that use semiconductors, and when this is used, the absolute value of the strength of an abnormal magnetic field caused by an abnormal current generated by a short-circuited electrode plate is detected. However, sufficient measurement accuracy cannot be obtained simply by measuring the strength of the magnetic field on the electrode plate. This is because a large number of electrode plates are arranged in an electrolytic cell, and since a large number of electrolytic cells are provided in this type of metal electrolytic refining factory, the electrolytic cell is affected by the magnetic field from other electrode plates.
In addition, the magnetometers using semiconductors have large variations in their characteristics, and the measured values also vary greatly depending on the room temperature and the angle and position of the magnetometer with respect to the electrode plates. It must be said that it is unreliable to identify a shorted electrode plate based only on the absolute value of a single tank. In view of the above-mentioned conventional technology, the present invention is capable of detecting an abnormality in an electrode plate with high precision in a short measurement time, and also detects an abnormality in a magnetoelectric transducer which is a sensor for this detection. An object of the present invention is to provide a current detection device. The structure of the present invention that achieves the above object includes a frame that straddles an electrolytic cell in which a large number of electrode plates, which are anodes and cathodes, to which current is supplied via electrode plate conductors connected to the upper ends thereof, are arranged. , a large number of rods suspended from this frame and formed to be able to move up and down; a stopper that comes into contact with the electrode plate conductor to restrict its lowering position; A large number of detection parts each having an iron core, an excitation coil wound around the iron core, and a magnetoelectric transducer mounted on the iron core adjacent to the excitation coil, and each of which is fixed to the lower end of the rod; A shield member magnetically shields each detection section by pulling up the detection section, V _H is the output of the detection section due to the current of each electrode plate, V _F is the output of each detection section based on the reference magnetic flux from each exciting coil, and each detection section When the non-excited output of is V ₀ , calculate (V _H - V ₀ )/(V _F - V ₀ ) for each detection section, and compare each calculated value with the average value of this calculated value for all detection sections. V H is the output of the magneto-electric transducer based on the current of each electrode plate, V _F is the output of each magneto-electric transducer based on the reference magnetic flux produced by each exciting coil, and V _F is the output of each magneto-electric transducer based on the reference magnetic flux produced by each exciting coil. The output of each magnetoelectric conversion element based on the reference magnetic flux of opposite polarity is -V _F , and the non-excitation output of each magnetoelectric conversion element is V ₀
When (V _H - V ₀ )/(V _F - V ₀ ) is calculated for each detection part, each calculated value is compared with the average value for all the detection parts to determine if there is an abnormality in the electrode plate. , and if the sum of V _F and -V _F is not within a predetermined range near zero centered on zero, or V _F or -V _F is zero or smaller than a predetermined value near zero. and an arithmetic processing unit that determines that the magnetoelectric transducer is defective if the magnetoelectric transducer is defective. Embodiments of the present invention will be described in detail below based on the drawings. As shown in Figures 1a and 1b, each row of the electrode plate 1 as an anode and the electrode plate 2 as a cathode has a number of 10
Multiple rows (2 rows in the diagram) of tanks (35 tanks in the diagram)
Several ten sheets (44 sheets in the figure) are alternately arranged in each electrolytic cell 3. At this time, the electrode plate 1 and the electrode plate 2 are connected to the electrode plate conductors 4 and 5 connected to the electrode plates 1 and 2, respectively, and a common electrode plate in which the electrode plate conductors 4 and 5 are collectively connected. It is connected to the plus side and minus side of a power source 8 via conductors 6 and 7, respectively. During tank inspection work, predetermined measurements are performed using the electrode plate conductors 4 and 5. That is, when the abnormal current detection device main body 9 according to this embodiment runs on the rail 10, the strength of the magnetic field created by the current flowing through the electrode plates 1 and 2 for each tank is determined by the portions of the electrode plate conductors 4 and 5. It is now being measured by 2a to 2c show the abnormal current detection device body 9 extracted and enlarged. As shown in the figure, the same number of rods 12 as the electrode plates 1 are vertically movably suspended from a frame 11 that straddles the electrolytic cell 3, corresponding to the spacing between adjacent electrode plates 1. A detection section 13 is fixed to the tip of this rod 12. The stopper 15 restricts the downward movement of the detection section 13 at this time. Further, a shield member 16 is provided between the frame 11 and the detection section 13, and by pulling up the frame 11, the detection section 13 can be housed and the detection section 13 can be magnetically shielded from the surrounding magnetic field. . Further, the detection unit 13 detects the iron core 13a, as shown by extracting and enlarging this part in FIGS.
It has an excitation coil 13b and a Hall element 13c. Of these, 13 cores have undergone acid-proofing treatment.
a focuses the magnetic flux formed by the current flowing through the electrode plate conductor 4. For this purpose, it has a stopper 13d that comes into contact with the upper surface of the electrode plate conductor 4 to restrict the lowering of the detection part 13, and also has an opening 13e that opens downward so as to be able to straddle the electrode plate conductor 4. That is, the iron core 13a forms a quasi-closed magnetic path. Further, the excitation coil 13b is for generating a reference magnetic flux, and is attached to the iron core 13a so as to be capable of DC excitation.
The Hall element 13c is a magnetoelectric transducer and is inserted into a gap provided in the iron core 13a adjacent to the excitation coil 13b, and its output can be taken out to the outside via a cable 17. This cable 17 also has the function of supplying DC voltage to the excitation coil 13b. The number of detection units 13 at this time is of course appropriately selected according to the number of electrode plates 1, but does not necessarily have to be the same number. FIG. 4 shows magnetic flux density-output characteristic diagrams for three different Hall elements 13c. At this time, the horizontal axis is the magnetic flux density B (gause), and the vertical axis is the Hall element output V.
(mV) respectively. Referring to the same figure,
When the Hall element input current is kept constant as the rated DC, it exhibits linear characteristics with extremely high accuracy and small errors within a certain magnetic flux density range. This range is even larger than the magnetic flux density due to the short-circuited electrode plates 1 and 2. Furthermore, although there is a considerable difference in ambient temperature depending on the type of Hall element 13c, it is expressed by multiplying the above-mentioned linear characteristic by a certain constant coefficient. In other words, the variations in the characteristics of the Hall element 13c are the difference in the unbalanced voltage V ₀ which is the Hall element output V in non-excitation (when B = 0), the difference in the slope with respect to the magnetic flux density B, and the difference in the temperature coefficient. . By the way, the Hall element output V is expressed by the following equation. V=(1+α・T)(K _H・B+V ₀ ) where: V ₀ = unbalanced voltage, B = magnetic flux density, α = temperature coefficient, T = rising temperature, K _H = power generation constant. Therefore, as shown in Figure 5. , the output V _H of the Hall element 13c due to the measured electrode current, and the output V of the Hall element 13c obtained by housing the detection unit 13 in the shield member 16 and applying a DC voltage to the excitation coil 13b.
(V _H −V ₀ )/(V _F −V ₀ ) is calculated based on _F. At this time, if the time to read the measured value is on the order of several minutes, the temperature change can be ignored. Therefore, the calculated value from the above calculation is B _H /B _F . The value of is calculated by determining the magnetic flux density B _H due to the measured electrode current with respect to the magnetic flux density B _F due to the exciting coil 13b, which has no influence on the characteristics of the Hall element 13c, that is, the unbalanced voltage _V 0 , the power generation constant K _H and the temperature coefficient α. This is a numerical value that indicates whether it is double. At this time, read the output V _H of the Hall element 13c due to the electrode current measured, then read the output V F of the Hall element 13c obtained by applying a DC voltage to the excitation coil 13b, and finally read the output V _F of the Hall element 13c when not excited. If you read the output V ₀ of , the output V ₀ includes the residual magnetism and also serves as a correction for it. In other words, if a magnetic field with a magnetic flux density B _F by the excitation coil 13b is uniformly applied to the Hall element 13c of each detection section 13, the calculated values corresponding to each electrode plate 1 are summed, averaged, and the value is multiplied by the set value. When it is larger or smaller, it can be detected as a short circuit electrode plate or a poor contact electrode plate, respectively.
To apply a uniform magnetic field to the Hall element 13c, each excitation coil 13b is connected in series to the same DC power supply, or depending on the required detection accuracy, each excitation coil 13b is connected in parallel to the same DC power supply. Just do it. At this time, variations in the internal resistance of each exciting coil 13b can be ignored. If you organize and write the above,

[Formula] The electrode plate 1 of No.i for which the following relationship holds is a short-circuit electrode plate.

[Formula] The electrode plate 1 of No.i for which the following relationship holds is the electrode plate with poor contact. However: V _Hi is the detection part 1 by the i-th electrode plate 1
3, V _Fi is the output of the detection unit 13 by the i-th excitation coil 13b, V _0i is the non-excitation output of the detection unit 13 by the i-th Hall element 13c, K ₁ and K ₂ are manual setting values, A _i is the quadratic function correction coefficient of pole No.i, i is the i-th electrode plate 1, and i=2~
43, i≒1,44. When i=1,44, that is, the 1st and 44th electrode plates 1, generally the left end of the electrode plates 1 arranged laterally in one electrolytic cell 3 (see Fig. 1a) Since there is only one electrode plate 2 corresponding to the electrode plate 1 at the right end, the current is normally about half of the current flowing through the other electrode plates 1 during normal operation. Therefore, the judgment reference value is also half of that in the above formula, and for this reason, in the above formula, the average of 44 poles is divided by 43. If we organize and write about i=1,44, If the following relationship holds true, it is a short-circuited electrode plate. If the following relationship holds true, it is a board with poor contact. If such arithmetic processing is performed, the Hall element 13c can be used as it is without any problem without modifying or adjusting the characteristics of the Hall element 13c. FIG. 6 shows a block diagram of the system of this embodiment including the arithmetic processing section 18 that performs the arithmetic processing. In the figure, 18a is a counter, 18b is an amplifier, 18c is an A/D converter, 18d is an input/output interface, 18f is a microcomputer,
18g is a peripheral device controller, 18h is a printer, and 18i is a program memory 18j is an operation/display section. Therefore, the outputs V of the Hall elements 13c from No. 1 to No. 44 are read by sequentially switching the operation switch 19, and after predetermined calculations are performed by the microcomputer 18f, the results are outputted to the printer 18h. At this time, a rated DC current is supplied from the power supply 20 to each Hall element 13c. Furthermore, this direct current is supplied via the reversing switch 21. Therefore, by operating the reversing switch 21, the polarity of the Hall element input current supplied to the Hall element 13c can be easily reversed. Further, current is supplied from a power source 22 to each exciting coil 13b to generate a reference magnetic flux. In this embodiment, in order to detect the abnormal current flowing through the electrode plates 1 and 2, the frame 11 is placed above the electrolytic cell 3 to be measured, and the frame 11 is lowered to detect the detecting section 13.
The iron core 13a straddles the electrode plate conductor 4. At this time, since the iron core 13a forms a quasi-closed magnetic path, most of the magnetic field caused by the current flowing through the electrode plate conductor 4 is focused on the iron core 13a. Furthermore, the lowering of the detection unit 13 is regulated by the contact between the stopper 13d and the electrode plate conductor 4, and the
can move slightly depending on the height of the electrode plate conductor 4, so it can follow some irregularities on the upper surface of the electrode plate conductor 4, and therefore errors due to imbalance in the height of the electrode plate conductor 4 can be avoided. does not occur. Furthermore, when measuring this electrode current, the detection unit 13 comes into contact with the electrode plate conductor 4 via the stopper 13d, but the temperature at the mounting position of the Hall element 13c is lower than the short-circuited electrode plate temperature of 110°C to 150°C at this time. The increase is still around 10°C even after 24 hours. After detecting the electrode plate current, that is, the output V _H in this way, the reference magnetic flux is set by raising the frame 11 and supplying a predetermined DC current to the excitation coil 13b with the detection unit 13 housed in the shield member 16. The output V _F of each detection unit 13 is measured. Thereafter, by deenergizing the excitation coil 13b, the output of each detection section 13 at that time, that is, the non-excitation output V ₀ is measured.
At this time, since the detection unit 13 is magnetically shielded by the shield member 16, the influence of the surrounding magnetic field that causes errors can be eliminated. The output V obtained as
Arithmetic processing unit 1 based on _H , output V _F and output V ₀
8, the value of (V _H −V ₀ )/(V _F −V ₀ ) is calculated, and this calculated value is further compared with the average value to detect an abnormality in the electrode plate 1. On the other hand, abnormality determination of the Hall element 13c is performed as follows. Hall element 13c when magnetic flux density B is plotted on the horizontal axis and Hall element output V is plotted on the vertical axis
In general, the output characteristics of the filter are as shown by the solid line in FIG. In the case of this Hall element 13c, a Hall element output of V _F1 (mV) is generated at a certain magnetic flux density B _F1 (gause). At this time, when the changeover switch 21 is operated, the Hall element 13c
By switching the input polarity of the Hall element 13c, the function of the Hall element 13c becomes the characteristic shown by the dotted line in FIG. 7, that is, the characteristic is symmetrical about the horizontal axis, and the magnetic flux density B _F1
(gause), a Hall element output V of −V _F1 (mV) should be generated. In other words, if a magnetic field with a magnetic flux density B _F1 (gause) is generated by energizing the excitation coil 13b, this value will not change rapidly, so the input side polarity of the Hall element 13c can be changed by the above-mentioned operation. If , the algebraic sum of the Hall element output V _F1 before switching and the Hall element output −V _F1 after switching becomes approximately 0. Therefore, the Hall element 13 satisfies the formula |V _F1 +(-V _F1 )|-α>0 (where α is a manually set value)
The Hall element 13c where c and Hall element output V _F1 , -V _F1 =0 and |V _F -V ₀ | -β<0 is determined to be abnormal. |V _F1 - (V _F1 ) | -
Regardless of when α>0, when V _F1 , -V _F1 = 0, there is a high possibility that the wiring on the input side or output side of the Hall element 13c is causing a contact failure or is disconnected. be. Since there is an unbalanced voltage V ₀ , it is highly unlikely that the Hall element output V becomes zero even when not energized. In this embodiment, one Hall element 13c is used, the same number as the electrode plates 1 of the electrolytic cell 3, so one problem is the detection of a deteriorated or damaged Hall element 13c. As mentioned above, the characteristics change depending on the unbalanced voltage, power generation constant, temperature, etc., and it is impossible to determine the normal output voltage value, maximum output voltage value, etc. of each Hall element 13c. Therefore, it is difficult to judge whether the Hall element 13c is deteriorated or damaged, but according to the present embodiment, by performing the above-described operations, it is possible to easily judge whether the Hall element 13c is good or bad. As specifically explained above with the examples,
According to the present invention, since the current flowing through the electrode plate can be measured for each electrolytic cell at once, the measuring time can be dramatically shortened. Moreover, since the detecting section having the magnetoelectric conversion element has an iron core forming a quasi-closed magnetic path, the necessary magnetic flux can be focused, and the detecting section is formed to be movable up and down. Since the relative position with respect to the detected part can always be kept constant, the influence of irregularities on the upper surface of the electrode plate on the measured value can be eliminated.
Therefore, it is possible to reliably detect an abnormal state with high precision that is sensitive to even the slightest abnormality such as a weak short circuit. Furthermore, the output V of the detection section due to the electrode plate current
_H , the output V _F of the detection section when a standard DC current is supplied to the excitation coil wound around the iron core adjacent to the magnetoelectric conversion element with each detection section housed in a shield member and magnetically shielded; Calculate the formula (V _H - V ₀ )/(V _F - V ₀ ) based on the non-excitation output V ₀ with each detection part magnetically shielded,
Since it has an arithmetic processing unit that determines abnormality of each electrode plate by comparing this calculated value and the average value of this calculated value, it is possible to remove the influence of variations in the characteristics of the magnetoelectric transducer, and the determination result is further improved. It becomes certain. Also, if the absolute value of the sum of the outputs V _F and -V _F of the magnetoelectric transducer becomes a predetermined value or more, or V
Since it is detected whether the absolute value of _F or -V _F is less than a predetermined value, it is also possible to detect an abnormality in the magnetoelectric conversion element.

[Brief explanation of the drawing]

Fig. 1a is an explanatory plan view showing an electrolytic cell whose current value is measured by an abnormal current detection device according to an embodiment of the present invention, and Fig. 1b is an explanatory drawing when it is cut with X-X rays. , Figure 2a is a front view of the main body of the abnormal current detection device extracted and enlarged, Figure 2b is its top view, Figure 2c is its right side view, and Figure 3a is one of the detection parts. FIG. 3b is a sectional view taken along YY line, and FIG. 3c is a front view extracted and enlarged.
A Z-line cross-sectional view, Fig. 4 is a magnetic flux density-output characteristic diagram of three different Hall elements, with the horizontal axis showing magnetic flux density and the vertical axis showing Hall element output, and Fig. 5 shows the measurement using the device of this embodiment. FIG. 6 is a block diagram systematically showing the entire device of this embodiment,
FIG. 7 is a magnetic flux density-output characteristic diagram of the Hall element when the polarity of the current supplied to the Hall element is switched, with the horizontal axis representing the magnetic flux density and the vertical axis representing the Hall element output. In the drawing, 1 and 2 are electrode plates, 3 is an electrolytic cell, 4 is an electrode plate conductor, 9 is an abnormal current detection device main body, 13 is a detection section, 13a is an iron core, 13b is an exciting coil, 1
3c is a Hall element, 13d is a stopper, 13e is an opening, 16 is a shield member, and 18 is an arithmetic processing section.

Claims (1)

[Scope of Claims] 1. A frame that straddles an electrolytic cell in which a large number of electrode plates, which are anodes and cathodes, to which current is supplied via electrode plate conductors connected to the upper ends thereof, are arranged; A large number of rods are formed to hang down and be movable up and down, a stopper that comes into contact with the electrode plate conductor to restrict the lowering position, an annular iron core whose position is regulated by the stopper and has an opening that straddles the electrode plate conductor, and this iron core. It has an excitation coil wound around the rod, a magnetoelectric transducer mounted on the iron core adjacent to the excitation coil, and a large number of detecting parts each fixed to the lower end of the rod; A power source that supplies a current that causes the excitation coil to generate a predetermined reference magnetic flux, a shield member that magnetically shields the detection section by pulling up the detection section, and an output of the magnetoelectric transducer due to the current of each electrode plate.
_H , when the output of each magnetoelectric conversion element based on the reference magnetic flux from each excitation coil _{is VF} , and the non-excitation output of each magnetoelectric conversion element is _V0 , ( _VH - V ₀ ) / (V _F - V ₀ )
An abnormality in metal electrolytic refining, characterized in that it has an arithmetic processing unit that calculates for each detection unit and compares each calculated value with an average value of the calculated values for all detection units to determine an abnormality of an electrode plate. Current detection device. 2. A frame that straddles an electrolytic cell in which a large number of electrode plates are arranged, an anode and a cathode to which current is supplied via electrode plate conductors connected to the upper end, respectively, and a frame that is suspended from this frame and can be moved up and down. a stopper that comes into contact with the electrode plate conductor to restrict the lowering position; an annular iron core whose position is regulated by the stopper and has an opening that straddles the electrode plate conductor; and a ring-shaped iron core that is wound around the iron core. The excitation coil has an excitation coil and a magnetoelectric transducer mounted on the iron core adjacent to the excitation coil, and a large number of detection parts each fixed to the lower end of the rod; A power supply that supplies a current that generates a magnetic flux, a shield member that magnetically shields each detection section by pulling up the detection section, and an output of the magnetoelectric conversion element due to each electrode plate current to V.
_H is the output of each magnetoelectric transducer based on the reference magnetic flux from each exciting coil, V _F is the output of each magnetoelectric transducer based on the reference magnetic flux of opposite polarity from each exciting coil.
When V _F and the non-excited output of each magnetoelectric conversion element are V ₀ , calculate (V _H − V ₀ )/(V _F − V ₀ ) for each detection part, and calculate each calculated value as the total of this calculated value. In addition to determining the abnormality of the electrode plate by comparing it with the average value related to the detection part, if the sum of V _F and -V _F is not within a predetermined range near zero centered on zero, or if V _F or -
1. An abnormal current detection device in metal electrolytic refining, comprising: an arithmetic processing unit that determines that a magnetoelectric conversion element is defective when V _F is zero or smaller than a predetermined value near zero.