JPS6161520B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrode monitoring device for a metallurgical arc furnace, and in particular, by measuring the amount of elevation of the electrode, it is possible to monitor the length of the electrode, the amount of erosion thereof, or the position of the hearth that changes with each charge. We propose an electrode monitoring device that can be advantageously used for this purpose.

Conventionally, in the operation of a metallurgical arc furnace, an operator visually determines the length of an electrode prior to melting, and based on this, the operator lowers the electrode into the arc furnace while assuming its lower end position to ignite the arc. Since then, electrode management operations have mainly been based on the intuition of operators. However, if the electrode length is not accurately known, the distance between the melting material and the lower end of the electrode is also unknown, which increases arc power fluctuations, worsening power costs and reducing melting efficiency.

In addition, with the above-mentioned conventional technology, it is not possible to know the exact amount of electrode melting loss after the melting is completed, making it difficult to grasp the timing of adding electrodes and accurate electrode consumption.

Moreover, in the case of the conventional technology, the position of the arc furnace hearth bottom (the hearth surface level that fluctuates with each charge due to floor excavation, etc.) cannot be accurately determined, so the hearth lining can be repaired and protected. The problem was that this could not be done properly, leading to steel leaking from the bottom of the furnace.

In view of the above-mentioned drawbacks of the prior art, this invention
The present invention provides an electrode monitoring device that uses two types of detectors and a calculation device to accurately measure the amount of electrode elevation around a measurement reference point, thereby calculating the electrode length and hearth position. This is the purpose. The details of the structure will be explained with reference to a preferred example applied to an electric furnace for steel making.

FIG. 1 shows the electrode lifting and lowering mechanism of the arc furnace 1. As shown in FIG. Reference numeral 2 in the figure represents an electrode, which is attached to the tip of an arm 4 that moves up and down along the mast 3. The electrode 2 is raised and lowered by moving the arm that supports it through the prime mover 6, reducer 7, drum 8, and suspension rope 5.
This is done by raising and lowering using the Therefore,
If some kind of measurement is performed on such an arm drive mechanism, the vertical movement width of the electrode 2 can be measured.

Therefore, in the present invention, an electrode lifting distance detector 9, which is preferably a pulse generator or a celsin detector, is attached to the reducer 7, and the lifting distance is detected from the rotation speed of the reducer 7, for example. That's what I did. However, the electrode 2
It is possible to measure the lifting distance of the electrode, but the measured value alone cannot accurately determine the electrode length or the furnace bottom level.

Therefore, in order to set a measurement reference point for electrode movement, the present invention provides a method for determining the distance between the position (height) indicated by the lower end of the electrode and the upper end of the furnace body of the arc furnace 1 when the arm 4 is placed at the upper limit. An electrode lower end detector 10 was installed at an arbitrary position along the electrode hoistway. This electrode lower end detector 10 uses a laser device as a preferred example, and also uses a limit switch and a phototube to detect the lower end of the electrode passing through this position when moving up and down. By calculating the detected value together with the detected value of the lifting distance, the electrode length and the furnace bottom position can be calculated. Next, the method of these calculations will be explained.

First, the calculation of the electrode length will be explained based on _FIG .
If the arm descending distance when the lower end crosses the measurement reference point is L _B , then the electrode length L _C
can be determined by the following equation: Electrode length L _C =L _A -L _B.

The above electrode length L _C is measured before and after the melting operation, and the difference is found to be 1
You can also know the exact amount of electrode consumption for each charge.

Next, a method for detecting the hearth position using the device of the present invention will be explained based on FIG. The symbols shown in the drawings are defined as follows.

L _A : Distance from the upper limit of arm 4 to laser beam 11 of the electrode lower end detector. (Fixed) L _B : The electrode tip is exposed to laser beam 1 from the arm 4 limit.
Distance by which the arm 4 is lowered until the light reaches 1.

L _C : Electrode length.

L _D : Lowering distance of the arm 4 from the rays of the laser beam 11 until the electrode 2 touches the hearth 1a.

L _E : Distance between the electrode lower end detector 10 and the uppermost limit of the furnace body.
(Fixed) L _T : Distance between the upper limit of arm 4 and hearth 1a. (After completion of melting) L _R : Hearth 1a position. (After melting is completed) The above measurement value is obtained by lowering the electrode 2 from the upper limit position of the arm, making the laser beam 11 of the electrode lower end detector 10 shine at its tip, and then continuing until the tip reaches the arc hearth 1a. Since measurements are taken while the electrode is being lowered, L _B , L _C , L _D , and L _T are calculated by the electrode length and hearth position calculating device 12 through this operation. In addition,
In the figure, 13 is a laser controller, and 14 is a display panel. Further, whether the lower end of the electrode has reached the hearth is detected by the current value of the motor 6 or the tension of the hanging rope 5.

From the numerical values obtained as described above, the hearth position L _R is further determined using the arithmetic device. That is, L _T = L _B + L _C + L _D ... L _T = L _A + L _E + L _R ... L _A = L _B + L _C ...... From the formula, L _R = L _B + L _C + L _D − L _B − L _C -L _E L _D -L _E ......, and the hearth position can be accurately determined. Moreover, by comparing this hearth position with the previous measurement value, it is possible to calculate the amount of hearth erosion.

As explained above, according to the present invention, it is possible to accurately detect the length of the electrode, the amount of electrode erosion, the position of the hearth of the arc furnace, and the amount of erosion of the hearth. Therefore, the above-mentioned conventional problems can be overcome. In other words, power consumption and dissolution processing time are stabilized, power costs can be reduced, and the timing of adding electrodes can be determined.
It also becomes possible to accurately know the electrode consumption per charge. Furthermore, since the hearth position can be detected accurately, the hearth can be repaired quickly, and steel leakage can be completely prevented.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an electrode lifting mechanism and a circuit for calculating a lifting distance, FIG. 2 is an explanatory diagram of an electrode length calculation method, and FIG. 3 is an explanatory diagram of a hearth position calculation method. 1... Arc furnace, 2... Electrode, 3... Mast,
4... Arm, 5... Suspension rope, 6... Motor, 7...
... Reduction gear, 8 ... Drum, 9 ... Electrode lifting distance detector, 10 ... Electrode bottom end detector, 11 ... Laser light, 12 ... Arithmetic device, 13 ... Laser controller,
14...Display board.

Claims (1)

[Claims] 1. At the measurement reference point determined between the electrode lifting distance detector attached to the electrode holding arm lifting drive and the lower end position of the electrode and the upper end position of the arc furnace at the upper limit of the arm along the electrode hoistway. An electrode monitoring device for an arc furnace consisting of an installed electrode bottom end detector and an electrode length and hearth position calculation device.