JPH10288464A - Regulating method for quantity of sand to be charged in steel tap hole of electric furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain automatic regulation of the quantity of sand to be charged, resulting from a change in a steel tap hole, by determining excess or deficiency of the quantity of charged sand on the basis of a difference between a reference upper position of the sand necessary for preventing molten steel from leaking out of the steel tap hole and a detected upper position of the sand charged after release of the steel and by conducting recharge at the time when the quantity of the charged sand is deficient. SOLUTION: A reference upper position of sand to be charged in a steel tap hole is the upper position of the sand necessary for preventing molten steel from leaking out of the steel tap hole in the cource of melting and this upper position of the sand is stored in a control device as the reference upper position. After the sand is charged in the steel tap hole after release of the molten steel in a charging time set for the previous charge, the upper position of the sand is detected by an elevating short position detector and a deficiency is recharged in the case when the detected upper position is lower than the reference upper position. The recharge is conducted for a charging time enough for covering the deficiency, i.e., for a selected additional time. By this method, the quantity of charged sand can be checked automatically by detecting the upper position of the sand and also the quantity of recharge in the next time can be regulated according to the quantity of the charge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the amount of sand filling a tapping hole of an electric furnace when automatically sand-filling a tapping hole of an electric furnace.

[0002]

2. Description of the Related Art After tapping, a tapping hole of an electric furnace is filled with sand and closed to prepare for the next furnace operation for melting and refining. Japanese Patent Application Laid-Open No. 7-4852 describes an automatic sand filling adjustment device for a tapping hole of an electric furnace. In the automatic sand filling apparatus described in the above publication, the entire peripheral wall of the furnace body is formed by a water-cooled panel, the hearth portion is lined with a refractory, and a furnace lid is provided on the upper surface. One side of the furnace body has a working port, the other side has a protruding tapping section, and a tapping port is formed at the bottom thereof. The tap hole is formed of a refractory material. After tapping, sand for closing the tap hole is dropped from a sand hopper provided above the tap hole by operating a gate valve mechanism. Above the tap hole, there is a hollow obstacle removal device that operates when the tap hole is reduced in diameter due to slag and metal ingot, and returns to the normal hole diameter. It also has a function of preventing sand falling from the hopper to the tap hole from scattering around the tap hole.

Further, in order to measure the shape of the hole of the tap hole, a light-emitting body which has moved above the tap hole and a light receiving device which has also moved below the tap hole are attached to the tap hole. Detects the presence or absence of a hole and shoots a tapping hole.This image is processed by an image processing device to calculate the volume of the hole to determine the required amount of sand, and to activate the gate valve mechanism to tap a predetermined amount of sand. Put it in the mouth to end the closing work.

[0004]

A method for calculating the required volume of sand by calculating the volume of a hole by the image processing apparatus is as follows.
Since the tap hole is photographed between the tap hole and the luminous body and the light receiving device, it is not possible to accurately photograph the degree of erosion or adhesion inside the hole, and therefore, the hole volume determined by image processing Since the volume of the hole differs from the actual hole volume, it is not possible to obtain an accurate amount of sand. Further, since the inside of the hole cannot be accurately grasped from the image of the tap hole, it is not possible to accurately judge the time of replacement of the refractory around the tap hole.

[0005] The present invention provides an electric furnace which can automatically adjust the amount of sand charged in accordance with a change in the tapping hole, and can detect the timing of replacing the refractory around the tapping port and an abnormality in the sand supply system. An object of the present invention is to provide a method for adjusting the amount of sand packed in a tap hole.

[0006]

SUMMARY OF THE INVENTION The method for adjusting the amount of sand packed in a tap hole of an electric furnace according to the present invention is based on the requirement that the upper position of sand that does not allow molten steel to leak from the tap hole during melting is used as a reference upper part. After sand is fed into the tapping hole after tapping, the upper position of the input sand is detected, and the difference between the detected upper position and the reference upper position is used to determine the excess or deficiency of sand input, and It is characterized in that the sand is re-input when water is insufficient.

[0007] When it is determined that the re-injection of the sand is equal to or more than the specified number of times, or when the amount of the sand is determined to be equal to or more than the specified value, the sand input is stopped.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a sand filling apparatus used in the sand filling adjusting method of the present invention, and FIG.
FIG. 1- (b) is a schematic diagram of one embodiment of the sand top position detection,
The entire peripheral wall of the furnace body is formed by a water-cooled panel 1, the hearth portion 2 is lined with a refractory, and a furnace lid 3 is provided on the upper surface. One side of the furnace body has a projecting tapping portion 4 and a tapping port 5 is formed at the bottom thereof. The tap hole 5 is formed of a refractory 6, and a tap hole lid 7 is provided below the tap hole.

A sand hopper 8 is provided above the tapping port 6, and a gate valve mechanism 9 is provided below the sand hopper 8. The opening time of the gate valve mechanism 9 is adjusted by a timer of the control device 10, and the amount of sand charged is adjusted by the opening time of the gate valve.

The sand hopper 8 is connected to chutes 11 and 12 for charging sand. The arrival at the upper part of the sand by the lowering of the lifting / lowering chute 12 is detected, for example, by the lifting / lowering chute 12 hitting the sand during the lowering,
Is performed when the detected value does not change within a certain period of time.

After the sand is fed into the tap hole 6, the elevating chute 12 descends toward the tap hole, detects the height of the upper surface of the sand by the above-described detection mechanism, and the elevating chute 12 rises. An elevating chute position detector 13 is provided on the elevating chute 12, and the elevating chute position detector 13 detects the position of the elevating chute 12 during elevating, thereby detecting the upper position of the sand.

As shown in FIG. 1- (b), the elevating chute position detector 13 uses, for example, a proximity switch 13 and slits 14 are provided at regular intervals in the elevating chute 12. The number of slits passing through the proximity switch 13 is counted until the elevating chute 12 stops for a certain period of time.
2 is detected. A signal related to the position detected by the lifting / lowering chute position detector 13 is input to the control device 10.

The control device 10 controls the CPU to calculate the excess or deficiency of the sand input amount from the difference between the detected upper position of the sand detected from the position-related signal and the reference upper position serving as a reference in the prescribed sand input amount. The opening time of the gate valve is automatically set by a soft timer by a signal.

Next, the method for adjusting sand filling according to the present invention will be described. FIG. 2 is a flowchart of the sand filling adjustment method of the present invention. After the tapping is completed, the sand in the sand hopper is opened for a set time by opening the gate valve mechanism at the lower part of the sand hopper, and the sand is discharged through the chute and the elevating chute. Put sand into the steel mouth. The reference upper position of the sand to be put into the tap hole is the upper position of the sand required to prevent molten steel from leaking from the tap hole during melting, and this upper position of the sand is stored in the control device as the reference upper position. Let it.

First, after replacing the tapping hole, the amount of sand input is determined according to the tapping diameter so that the sand reaches the above-described reference upper position, and the sand input time corresponding to the input amount is set in the timer. I do. After that, the gate valve is opened for the set time of the timer, sand is fed into the tapping port, and then the gate valve mechanism is closed.

After the sand is charged, the lifting chute is lowered. During the descent, the slit provided on the lifting chute is counted by the lifting chute position detector provided on the lifting chute, and the position of the lifting chute is detected by the count number. If the position does not change within a certain period of time, it is determined that the lower end of the chute has come into contact with the upper part of the injected sand and has stopped, and the position of the upper part of the sand is detected.

Table 1 shows an example of the setting table.

[Table 1] If the detected upper position exceeds the reference upper position due to the detection of the upper position of the sand, the amount of sand to be supplied is equal to or greater than the specified amount. And reduce the next input time after tapping by that amount. For example, if the count number of the reference upper position is 4 and the count number of the detection upper position is 3, the count number is one less and the sand detection upper position is higher than the reference upper position. From the count number -1, the input time is set to -1 second. This input time is automatically set as the next input time.

On the other hand, when the detected upper position is lower than the reference upper position, the input sand is insufficient, so that the input increasing time is selected from the setting table according to the height difference, and the input time is accordingly reduced. Increase and automatically set this input time as the next input time.

When the detected upper position falls within the allowable range of the reference upper position, the set injection time is taken as the next injection time because the amount is an appropriate amount.

After tapping, sand is charged into the tapping port for the charging time set in the previous tapping, the gate valve is closed, sand is charged, the lifting chute is lowered, and the lifting chute position detector detects the sand. If the upper position of the sand is detected and the detected upper position is lower than the reference upper position, the input sand is insufficient, so select the increase time of the input from the setting table according to the height difference, and Re-enter. The re-injection time is re-input only for the shortage, that is, the increased time selected by the setting table.

After re-injection, the elevating chute is lowered, the upper position of the sand is detected by the elevating chute position detector, the excess / deficiency is determined by comparing with the reference upper position, and the time for the next sand injection is automatically set. .

While the tapping operation is repeated a number of times, the refractory around the tapping port melts away, so it is necessary to replace the tapping when the thickness of the refractory drops below a certain thickness. If the thickness of the refractory around the mouth decreases due to erosion and the volume of the tap hole increases, the amount of sand inevitably increases. Has been significantly increased, and it is determined that the thickness of the refractory has reached the replacement thickness of the refractory. Therefore, the injection is stopped and the refractory is replaced.

In charging the set amount of sand by recharging,
If the calculated number of times of sand addition exceeds a predetermined number of times, for example, two times, it means that a predetermined amount of sand has not been cut out. If it comes out, the sand supply system such as the sand hopper and the gate valve mechanism will have a problem such as hopper abnormality and the specified amount has not been charged, so stop the sand charging and check the equipment. And then start loading.

[0024]

【The invention's effect】

(1) According to the present invention, the amount of sand charged can be automatically detected by detecting the upper position of the sand, and the next recharged volume can be adjusted based on the amount of sand charged. Thus, the worker can reliably input an appropriate amount of sand without performing any work on the machine side.

(2) By confirming the sand input amount,
Since the degree of erosion of the refractory around the tap hole can be known, it is possible to know the replacement time.

(3) An abnormality in the hopper can be detected by checking the number of times of sand injection.

[Brief description of the drawings]

FIG. 1 shows a sand filling apparatus used in the sand filling adjustment method of the present invention, FIG. 1- (a) is an overall view thereof, and FIG. 1- (b).
FIG. 3 is a schematic diagram of an embodiment of sand top position detection.

FIG. 2 is a flowchart of a sand filling adjustment method of the present invention.

[Description of Signs] 1 Water-cooled panel 2 Hearth section 3 Furnace lid 4 Tapping section 5 Tapping port 6 Refractory 7 Tapping port 8 Sand hopper 9 Gate valve mechanism 10 Control device 11 Chute 12 Elevating chute 13 Elevating chute position detection Vessel (proximity switch) 14 slit

Claims (3)

[Claims] 1. The upper position of sand that is necessary to prevent molten steel from leaking from a tapping port during melting is defined as a reference upper position, and after the sand is fed into the tapping port after tapping, the upper position of the injected sand is set. Detecting the difference between the detected upper position and the reference upper position, calculating the excess or deficiency of the sand input amount, and re-inputting the sand when the sand input amount is insufficient. How to adjust the amount of sand filling the mouth. 2. The method for adjusting the amount of sand packed in a tapping hole of an electric furnace according to claim 1, wherein when it is determined that the re-injection of the sand is more than a specified number of times, the injecting of the sand is stopped. 3. The method according to claim 1, wherein when the amount of sand to be charged is determined to be equal to or more than a specified value, the charging of sand is stopped.
Or the method of adjusting the amount of sand packed in the tapping hole of the electric furnace according to 2.