JP2910051B2 - Electrode length adjustment method and electrode length measurement device in arc furnace - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode length adjusting method and an electrode length measuring device in an arc furnace for melting a charging material such as a scrap.

[Conventional technology]

Generally, in an arc furnace, a graphite electrode is often used as an electrode for generating an arc.However, since this graphite electrode is consumed by an operation, it is necessary to replenish the electrode and replace the electrode holder at an appropriate time. It is necessary to adjust the electrode length so that the operation can be performed smoothly.

Conventionally, however, the length of graphite electrodes is controlled based on the visual experience of the on-site workers who operate the furnace. It has also been found that the subsequent process has been greatly affected.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems. An electrode length adjusting method capable of appropriately adjusting the electrode length according to the operation of a furnace, and an electrode length adjustment method used in the method, which can easily and accurately adjust the electrode length. It is an object of the present invention to provide an electrode length measuring device capable of measuring the length of an electrode.

[Means for solving the problem]

Thus, the method of the first invention of the present application is to provide an arc furnace in which a charging material is melted by arc heat of a graphite electrode held by an electrode holder. The projected total length obtained by subtracting the estimated electrode consumption amount corresponding to the new charging material melting power amount from the total electrode length calculated from these two dimensions is calculated from the predetermined minimum electrode length. When the electrode length becomes smaller, the electrode is replenished.Next, when the estimated lower length obtained by subtracting the expected electrode wear amount from the lower protrusion size becomes smaller than a predetermined minimum holder lower electrode length, a new charging material is charged. This is a method for adjusting the electrode length in an arc furnace, wherein the electrode is changed again later.

The apparatus according to the second aspect of the present invention further includes a holder position detector that generates a holder position signal corresponding to a height of the electrode holder from a reference position in conjunction with lifting and lowering of the electrode holder. An electrode top detector that detects the passage of the graphite electrode inserted into and removed from the furnace during the up-and-down stroke and issues an upper-end detection signal during the up-and-down stroke, and detects the passage of the electrode bottom during the up-and-down stroke to detect the lower-end detection signal. The upper electrode protruding dimension is calculated from the lower electrode detector to be emitted, the vertical distance between the reference position and the upper electrode detector, and the holder position signal of the holder position detector when the upper electrode is detected by the upper electrode detector. With the reference position and the vertical distance between the electrode bottom detector and the holder position signal of the holder position detector at the time of lower end detection by the electrode bottom detector An electrode length measuring device comprising a calculating circuit for calculating the lower protruding dimension of Luo electrode.

[Action]

According to the inventor's knowledge, the amount of consumption of the graphite electrode due to the melting of the charging material is almost proportional to the input electric energy (integrated electric energy). Is required with high accuracy. In the method of the first invention, the expected total length is obtained by subtracting the expected electrode consumption amount from the total electrode length obtained by measuring the graphite electrode, and is compared with the minimum electrode length required for the operation to determine whether or not the addition is necessary. So
The reliability of the judgment is high. Similarly, the expected lower side length is obtained by subtracting the expected electrode consumption amount from the lower end protrusion amount based on the actual measurement, and the determination of re-gripping is performed by comparing the estimated lower side length with the minimum holder lower length required for the operation. The electrode length and the electrode length required for the operation of the furnace and the electrode length under the holder are secured by performing the extension and the gripping of the electrodes based on the above determinations. Further, in the device of the second invention, the holder position signal generated by the holder position detector is read by the arithmetic circuit and subjected to addition and subtraction when the upper electrode detector detects the upper electrode end and when the lower electrode detector detects the lower electrode end. And output as the upper and lower protruding dimensions of the electrode.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, 1 is a DC arc furnace, 2 is a furnace body, 3
Is a furnace lid put on the furnace body, 4 is a furnace bottom electrode, and 5 is a graphite electrode which is a movable electrode. Reference numeral 6 denotes an electrode support arm whose base is guided up and down by an electrode support 7, and an electrode holder 8 for holding the graphite electrode 5 is attached to the tip of the electrode support arm. A DC power supply (not shown) is connected between the electrode holder 8 and the furnace bottom electrode 4. Reference numeral 10 denotes a driving device for raising and lowering the electrode, which is configured by connecting an electrode device 12 to a drum 11 for winding a wire, and 13 is a holder position detector including a pulse generator connected to a rotating shaft of the electric motor 12, from the reference position 14 to the lower end of the electrode holder 8 heights pulses proportional to H are those which emit a holder position detection signal S _H. 15 is furnace body 2
An electrode upper end detector for detecting the passage of the upper end of the graphite electrode 5 which is driven up and down when inserted into and removed from the inside, and 16 is an electrode lower end detector for detecting the passage of the lower end of the graphite electrode 5, both of which are laser beams It consists formula switch, on support 17 provided upright in parallel with the center line 2a of the furnace body 2 is provided from the reference position 14 as shown at the position of height h ₁ and h _2, respectively. In FIG. 2, reference numeral 18 denotes an electrode length calculation circuit, the details of which will be described later. The electrode length calculation circuit 18 includes a holder position detector 13, an electrode upper end detector 15, and an electrode lower end detector 16.
Thus, the electrode length measuring device 19 is configured. Numeral 20 denotes an electric energy setting device for inputting the amount of electric power for melting for one charge as an operation pattern of electric power KW with respect to time t to the replenishment judging circuit 21 as shown in the figure. Based on the force and the electrode upper length l ₁ and the lower length l ₂ from the electrode length measuring device 18, the necessity of electrode replenishment is determined by a calculation described later, and the replenishment necessity instruction signal is sent to the electrode length. This is output to the CRT 22 together with the data. 23 is a re-gripping judgment circuit,
a determination is gripping sort necessity by calculation described below from l _2, CR gripping sort necessity instruction signal with the length data of the electrodes
Output to T24.

Next, a method of adjusting the length of the graphite electrode 5 using the apparatus having the above-described configuration will be described. First, after the melting of the charge before melting the new charged material of interest, the graphite electrode 5 and the furnace lid 3 are pulled up. At this time, the length of the graphite electrode 5 is measured by the electrode length measuring device 19 (step in FIG. 3). The upper and lower ends of the graphite electrode 5 are detected by the upper electrode detector 15 and the lower electrode detector 16.
When passing in front of, the electrode length calculating circuit 18 by the detection signal output of each detector, the holder height H ₁ and H ₂ based on the holder position signal S _H of the holder position detector 13 during each pass And the installation height h ₁ of each detector 15, 16
And from h _2, to O connexion calculated upper protrusion amount l ₁ and the lower protruding quantity l ₂ of graphite electrodes 5 in the following equation.

_{l 1 = h 1 -H 1 -l} 0 ...... (1) l 2 = H 2 -h 2 ...... (2) where l _0: the vertical width dimension (see FIG. 1) of the electrode holder 8 this l ₁ and l and ₂ dimensions, and a dissolving power of the subject instrumentation Irizai by the power amount setting unit 20, by connexion該装Irizai dissolved at the end of the following formula entire length of the graphite electrodes 5 at (time t ₄₎ L _(t4) It is calculated, and performs the comparison between the minimum electrode length L ₀ required for operation. (FIG. 3 _{step) L (t4) = l 1} + l 0 + l 2 (t4) ... (3) l 2 (t4) = l 2 -δ ... (4) l 2 (t4) in the above formula when dissolved ends The lower protruding dimension of the electrode at t4, that is, the predicted lower length, and δ is the expected amount of consumption (consumed length) of the graphite electrode 5 from the start of dissolution to the end of t4, using a constant k obtained experimentally. It is calculated by the following equation.

When the total length of the graphite electrode L _(t4) is smaller than the minimum electrode length L _0, replenishment determination circuit 21 issues an electrode replenishment command _{S 1, l 1, l 2} , "replenished with the value of L _(t4) C is required
Display on RT22. (FIG. 2 step) The L _(t4) ≧ L ₀
In the case of, an indication of "no need to add" is displayed on the CRT 22. Then, when the above-mentioned "replenishment is required" is displayed, the graphite electrode 5 is replenished by a known method such as using an automatic electrode changing device. (Step in FIG. 3) It is conventional to select the number N of additional electrodes within a range in which the total electrode length does not exceed the allowable maximum length determined by the height of the Kenya. Also, this additional number N is added to the judgment circuit.
Input to 21 and perform the same calculation as above based on the l ₁ dimension in the state where N electrodes are added, and display “No need to add” on the CRT 22 to check if it is unnecessary to add. together, if to enter the new l ₁ dimension gripping sort judgment circuit 23, it is convenient to grasp replacement amount selecting at subsequent gripping sort.

On the other hand gripping re judging circuit 23, the (4) to calculate a predicted lower length l _{2 (t4)} by equation performs comparison between the minimum holder under the electrode length L ₁ required for this and the actual operation. (Third FIG step) when the expected lower length l _{2 (t4)} is smaller than the minimum holder under the electrode length L _1, the gripping sort decision circuit 23 electrode gripping sort command
Emit S _2, displays l _1, l with the value of _{2 (t4)} the display of "grab re necessary" to CRT 24. ₍ Fig. 2 step) and l _{2 (t4)} ≧ L
_{In the case of 1} , the display of "no need to change" is displayed on CRT24. Therefore When the can "grab replacement necessary" in the display, after charging the target instrumentation Irizai of Sukuratsupu such as the furnace body 2, the lower end of the graphite electrode 5 provided on the instrumentation Irizai, the upper protrusion amount l ₁ Within a range not exceeding, the opening and closing of the electrode holder 8 and the raising and lowering drive are performed by a known method, and the electrodes are gripped and changed.
(Step in FIG. 3) This gripping is performed when the scrap is mounted as shown in the operation pattern of the electric energy setting device 20 in FIG.
If the expected lower length l _{2 (t2)} is greater than the minimum holder electrode length L ₁ in may also be performed after TsuiSo Sukuratsupu charged. Further, the gripping amount α of the gripping is input to the gripping determination circuit 23, and (l ₁ −α) and (l ₂
+ Α) as the new l ₁ and l ₂ , perform the same calculation as above, display “Gripping not required” on the CRT 24 to confirm that the gripping is unnecessary, and replace the new l ₁ and l ₂ with If displayed on the CRT 24, it is convenient to know the length of each part of the electrode in a state where the length adjustment is completed before the start of dissolution.

If the charging material is melted while the electrode length is adjusted, the same measurement and calculation as described above are performed to prepare for the next charging material melting step.

The invention is not limited to the above embodiments, for example, the upper edge of the electrode upper in Example projecting dimension l electrode holder 8 the lower reference point _1, the upper reference point of the electrode lower projecting dimension l ₂ Although the lower edge of the electrode holder 8, is set to such these reference points for example vertical center position of the electrode holder 8, a portion of the vertical width dimension l ₀ of the electrode holder 8 l ₁ and l ₂
Be included in, may be set not using l ₀ at each operation, also Similarly, the height H above the reference point for measurement of the electrode holder 8, be defined at a position other than the lower edge of the electrode holder 8 Good. In addition, holder position detector 13, electrode upper end detector 15,
The electrode lower end detector 16 and the like may have a shape other than those described above, and the power amount setting device 20 may be a device that inputs the integrated amount of electric power for melting in the form of a numerical value.

Further, if the extension or the gripping of the electrode is automatically performed based on the electrode extension command of the extension determination circuit 21 or the electrode gripping instruction of the gripping determination circuit 23 and the length of each part of the electrode, it is determined by the operator. And operation can be further omitted, which is more preferable in terms of improvement in electrode length adjustment accuracy and labor saving.

In addition to the DC arc furnace, the present invention can be applied to an AC arc furnace having a plurality of movable electrodes. In this case, the length is adjusted by measuring and calculating the length of each electrode. Good. Furthermore, the second part of this application
The device of the present invention can determine the position of the lower end of the electrode by the output of the lower dimension of the electrode (l ₂ ) in addition to the measuring device for adjusting the electrode length described above. It can also be used as a measuring device for controlling an arc furnace that moves and melts.

〔The invention's effect〕

As described above, according to the method of the first aspect of the present invention, the electrodes are extended and gripped in anticipation of the expected amount of electrode consumption due to the operation of the furnace. Is reliably prevented, and wearing can be performed smoothly and efficiently.

Further, according to the device of the second invention, the upper and lower protruding dimensions of the electrode can be accurately and easily measured without visual observation.

[Brief description of the drawings]

FIG. 1 is an equipment layout diagram showing an embodiment of the present invention, FIG. 2 is a block diagram thereof, and FIG. 3 is a flowchart showing an electrode length adjustment procedure. 1 ... DC arc furnace, 5 ... Graphite electrode, 8 ... Electrode holder, 10 ... Driver, 13 ... Holder position detector, 14 ...
… Reference position, 15… Electrode top detector, 16… Electrode bottom detector, 18… Electrode length calculation circuit, 19… Electrode length measurement device, 20… Electricity setting device, 21… Circuit, 23
…… Replacement determination circuit.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F27B 3/00-3/28 F27D 11/08 H05B 7/00-7/22

Claims (2)

(57) [Claims] 1. An arc furnace in which a charging material is melted by arc heat of a graphite electrode held by an electrode holder, wherein a lower protruding dimension and an upper side of the graphite electrode with respect to the electrode holder before charging a new charging material. Measure the protrusion dimensions,
When the expected total length obtained by subtracting the expected amount of electrode consumption corresponding to the amount of electric power for dissolving the newly charged material from the total electrode length calculated from these two dimensions is smaller than a predetermined minimum electrode length, replenishment of the electrodes is performed. When an expected lower length obtained by subtracting the expected electrode consumption amount from a lower protruding dimension is smaller than a predetermined minimum holder lower electrode length, the electrode is re-gripped after loading a new charging material. Method of adjusting electrode length in furnace. 2. A holder position detector for generating a holder position signal corresponding to the height of the electrode holder from a reference position in conjunction with raising and lowering of the electrode holder, and being inserted into and removed from the furnace by being held by the electrode holder. An electrode upper end detector that detects the passage of the upper end of the graphite electrode during the ascending and descending process and issues an upper end detection signal, and an electrode lower end detector that detects the passage of the lower end of the electrode during the ascending and descending process and issues a lower end detection signal. ,
The upper distance of the electrode is calculated from the vertical distance between the reference position and the electrode top detector and the holder position signal of the holder position detector at the time of detecting the upper end by the electrode top detector, and the reference position and the electrode are calculated. An electrode length measurement device comprising: an arithmetic circuit for calculating a lower protruding dimension of an electrode from a vertical distance between the lower end detectors and a holder position signal of the holder position detector when the lower end detector detects the lower end. apparatus.