JPH0670918B2 - Arc furnace electrode replenishment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to supplementation of electrodes in various arc furnaces using electrodes such as arc furnaces for steelmaking, refining furnaces, vacuum arc furnaces, arc furnaces for waste melting treatment, etc. It is related to the method.

[Prior Art] Since the electrodes of the arc furnace are consumed, it is necessary to lower the electrodes toward the bottom of the furnace by the consumed amount. Therefore, the electrode gripper sequentially performs gripping.

Conventionally, when this gripping is performed, the electrode is lowered until the tip of the electrode once comes into contact with the hearth or scrap in the furnace, and the weight is applied to the hearth and the like. Therefore, it takes time and labor, and it is necessary to pay attention to the operation so as not to damage the tip of the electrode. In the case of a sludge treatment furnace in which the contents inside the furnace are sludge, in order to avoid immersing the electrode in the sludge, the electrode must be hung by a crane or hoist before it can be grabbed. It took more time and effort.

Therefore, the applicant of the present invention has proposed an arc furnace electrode gripping portion that solves this drawback, and filed a patent application as Japanese Patent Application No. 53-74752.

According to the present invention, a sub-grasper equipped with a clamp body which can be clamped and released is mounted on an main gripper which is attached to the tip of an electrode support arm and which has a clamp body which can be clamped and released. Supported by the clamp body of the auxiliary gripper and the clamp body of the main gripper is released while the clamp body of the auxiliary gripper is clamped to the electrode, the elastic body is deflected by the weight of the electrode. The electrode gripper for an arc furnace is characterized in that the electrode is lowered downward by an amount.

[Problems to be Solved by the Invention] In using the above-mentioned electrode gripper, immediately before the electrodes are exhausted, the next new electrode must be refilled and gripped to be replenished. This confirmation of the electrode replenishment time depends on visual inspection, and manpower is required for that. On the other hand, in Japanese Patent Laid-Open No. 59-5593, a method of detecting the amount of electrode wear by using an electrode ascending / descending distance detector has been proposed. However, in this proposal, when lowering the electrode toward the bottom of the arc furnace, the sensor provided at the upper part of the arc furnace detects the lower end position of the electrode, and the calculation device calculates it from the relationship with the electrode descent amount to reduce electrode wear. Since the amount is calculated, the lower end of the electrode must be detected and calculated each time the electrode is attached to the holder, and the melting work in the arc furnace must be interrupted for a long time each time the electrode is added. there were. In order to prevent such an interruption for a long time, careful positioning and the like were required in the work of adding electrodes. The present invention aims to solve such problems.

[Means for Solving the Problem] The present invention relates to a method for replenishing a replenishment electrode due to consumption of an electrode in an arc furnace, and detecting means for detecting a passing state of the electrode above a predetermined height above a holding member for holding the electrode. When the upper end of the electrode is detected by the detecting means,
It is a gist of a method for replenishing an arc furnace electrode, which is characterized in that it is judged that a predetermined amount of wear has been reached, an electrode addition request signal is issued, and a new electrode is added in response to the request signal.

[Operation] According to the method of the present invention, when the upper end of the electrode reaches a certain height, it is judged as the timing of replenishment, so that the replenishment should be carefully performed during the replenishment, and the melting work in the arc furnace should be performed for a long time. There is no need to interrupt.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram of a system in which the present invention is applied to a waste melting arc furnace,
2 to 5 are an enlarged explanatory view and an operational explanatory view of the main and auxiliary grippers in FIG.

In FIG. 1, reference numeral 50 is an arc furnace, which is provided with a waste input port to be treated, a generated gas discharge pipe, a slag discharge port, etc. (all not shown). Reference numeral 51 is the input waste, 52 is the base metal, and 53 is the slag composed of the inorganic substances in the waste floating above it. Reference numeral 54 denotes an electrode support column, which has an electrode supporting arm 2 protruding toward the arc furnace 50, and an electrode 5 is supported by a main gripper 1 provided at the tip of the electrode supporting arm 2. Above the main gripper 1, there is provided a sub-grip 9 that cooperates with the main gripper 1 to re-hold the electrode 5.
A stopper 31 is arranged between the sub-grasper 9 and the main gripper 1, and the sub-grasper 9 is held each time the electrode 5 is regripped.
Contact with.

Next, based on FIGS. 2 to 5, the main gripper 1 and the sub-grip 9
Will be described.

In the figure, the main gripper 1 is a known electrode gripper that is attached to the tip of an electrode support arm 2 that can be raised and lowered and that has a tightening body (not shown) that can be tightened and released freely. Reference numeral 3 is a rod for operating the tightening body, and 4 is a conductor for sending a current to the electrode 5. Reference numeral 6 denotes a lower plate fixed on the main gripper 1 via a bracket 7, and an electrode 5 is loosely inserted into a hole 8 formed in the lower plate. The auxiliary gripper 9 is an upper plate having the same shape as the lower plate 6.
On top of 10, fastening bodies 11, 12 and an air cylinder 13 for operating these fastening bodies are provided. That is, 14 is a bracket having an L-shaped cross section in which the base is fixed to the upper plate, and a pin 15 penetrating the bracket and the upper plate 10 is used to tighten the tightening body.
One end of 11,12 is pivotally supported. Further, one end of a tightening body operating lever 17 is pivotally attached by a pin 18 to a piston rod tip end portion of an air cylinder 13 pivotally supported by a bracket 16 fixed to the upper plate 10. The intermediate portion of the lever 17 is pivotally attached to the end of the tightening body 11 by the pin 19, and the other end of the link 21 pivotally attached to the end of the lever 17 by the pin 20 is the tightening body by the pin 22. It is pivotally attached to 12 ends. With the above configuration, the sub-grasper 9 has a self-centering function and the electrode 5
Even if there is a misalignment, the tightening bodies 11 and 12 are configured to grip the electrodes with substantially equal force from both sides of the electrodes. Note that 11a and 12a are the contact plates of the tightening bodies, which are fixed to the inner peripheral portion of each tightening body by bolts 23. The reference numeral 24 designates a hole formed in the upper plate 10 in which the electrode 5 is loosely inserted. On the other hand, 25 is a bolt,
Reference numeral 26 is a spring seat welded to this bolt.By tightening nuts 27 and 28 on the threaded portion that penetrates the upper plate 10, the bolt 2
5 is fixed to the upper plate 10. A compression spring 29 is mounted between the spring seat 26 and the lower plate 6, and the compression spring is preloaded by a bolt 25 to a predetermined initial compression force. Ie bolt
With the head of 25 contacting the lower surface of the lower plate 6 (the state shown in FIG. 2), the auxiliary gripper 9 was pre-compressed by the spring force (3 pieces) of the compression spring 29. It is set in the state. Reference numeral 30 is a guide hole into which the cylindrical portion of the bolt 25 is slidably inserted, and 31 is a cylindrical stopper, the lower end of which is welded to the lower plate 6 to control the amount of deflection of the compression spring 29. is there. Further, the stopper 31 is provided with a bracket 31a that contacts the upper plate 10 when gripping and a limit switch 31b that transmits a signal of contact between the bracket 31a and the upper plate 10 to the detector 55.

Next, the operation of the device having the above-mentioned configuration and the detection of the supplemental replenishment timing of the electrodes based on the operation will be described.

2 and 3 show a normal furnace operation state before electrode re-holding, in which the electrode 5 is gripped by the main gripper 1. On the other hand, the piston rod of the air cylinder 13 is in the retracted state, the tightening bodies 11 and 12 are released, and the sub-grasper 9 is at the uppermost position, so that there is a clearance a between the stopper 31 and the upper plate 10. Exists.

To replace the electrodes, compressed air is first supplied to the air cylinder 13 so that its piston rod is projected, and the electrodes are clamped by the clamping bodies 11 and 12 (see FIG. 5). Next, when the rod 3 is operated to release the clamped body of the main gripper 1 to release the electrode grip, the self-weight of the electrode 5 is applied to the sub gripper 9, so that the compression spring 29 bends and the upper plate 10 stops. The electrode 5 and the sub-grasper 9 are integrally lowered until they come into contact with the upper end (see FIG. 4). Next, when the electrode 5 is gripped by the main gripper 1 and then the electrode gripping by the sub gripper 9 is released by operating the air cylinder 13, the sub gripper 9 is pushed up by the compression spring 29 and is shown in FIG. Return to the state. Thus, one cycle of gripping is completed, and the electrode is moved downward by the deflection amount a (constant value) of the compression spring 29. Thereafter, the above operation is repeated an appropriate number of times as necessary to obtain a desired electrode withdrawal amount.

Next, a method of detecting the electrode addition timing will be described. In this example, as a detection method, a light projecting portion 56 and a light receiving portion 57, which are provided above the sub gripper 9 so as to face the electrode 5, are provided.
The new electrode replenishment time is confirmed by the detection signal emitted from the photoelectric switch composed of the combination of.

That is, the light projected from the light projecting portion 56 of the photoelectric switch is irradiated to and reflected by the head portion of the electrode 5 (shown by the dotted line) when the electrode 5 (shown by the dotted line) has not reached the lower limit of fall. Or less, and when the projection of light passes through the head portion of the electrode 5 (shown by the solid line) and reaches the light receiving portion 57, the signal is transmitted to the detector 55, and the detector 55 is newly installed. It gives an alarm that the time for refilling the electrodes has arrived.

As the photoelectric switch installed here, a commercially available known switch is applied. Further, the type thereof is not limited to the above-mentioned transmission type, but a recursive reflection type and a diffuse reflection type are also applicable. The installation height of the photoelectric switch should be decided for each arc furnace in consideration of the refilled electrode length, the arc furnace volume, the gripper height, etc. It is more economical to replace the electrode 5. In addition, 31 in the figure
a is a bracket provided on the stopper, and 31b
Is a limit switch. These are used to count the number of times the electrodes have been regripped, but are not directly relevant to the present invention.

[Effects of the Invention] The present invention detects the amount of electrode wear as described above, and when the amount of wear reaches a predetermined amount, an additional request signal is issued, and a new electrode is added based on the signal. In addition, the method is more accurate and safe than the conventional visual inspection method and requires no manual labor. As a result, the working efficiency of the arc furnace operation using the electrode is improved.

[Brief description of drawings]

FIG. 1 is an explanatory view of a system in which the present invention is applied to a waste melting arc furnace, and FIGS. 2 to 5 are enlarged explanatory views and operation explanatory views of the main and auxiliary grippers in FIG. 1 ... Main gripper, 2 ... Electrode support arm 5 ... Electrode, 6 ... Bottom plate 7 ... Bracket, 9 ... Sub gripper 10 ... Top plate, 13 ... Air cylinder 29 ... Compression spring , 31 …… Stopper 31a …… Scraper, 31b …… Limit switch 50 …… Arc furnace, 51 …… Waste 52 …… Base metal, 53 …… Slug 54 …… Electrode support, 55 …… Sensor 56… … Emitting unit, 57 …… Receiving unit

Claims (1)

[Claims] 1. A method for replenishing a supplementary electrode as a result of electrode wear in an arc furnace, wherein a detecting means comprising a light projecting portion and a light receiving portion is provided above a gripping member for gripping the electrode by a predetermined height. When the upper end of the electrode is detected by the detection means, it is judged that a predetermined amount of wear has been reached, an electrode addition request signal is issued, and a new electrode is added in response to the request signal Replenishment method.