JPS6176918A - Residual molten metal weight measuring method of electric furnace - Google Patents

Abstract

PURPOSE:To eliminate the influence of a tare weight by measuring indirectly the weight of residual molten metal in a furnace. CONSTITUTION:A data of a standard volume of residual molten metal at an inclined angle of a furnace body 5 at the construction a furnace with in-furnace lining is stored in an operating part 17 of a microcomputer, etc. Subsequently, an apparent volume of a discharge molten metal corresponding to a discharge molten metal quantity at the construction of the furnace with in-furnace lining is calculated by a discharge molten metal start inclination absolute angle and a discharge molten metal stop inclination absolute angle which are detected by a rotary encoder 12, at the time of a discharge molten metal start and a discharge molten metal stop which have been detected by a discharge molten metal detecting means 14. An apparent weight G1 of a discharge molten metal is measured by multiplying said volume by a specific gravity of a molten metal, a correction coefficient (k) being a ratio of G2/G1 is calculated from the weight G1 and an actual weight G2 of the discharge molten metal measured by a balance 16, and based on a data of a standard volume of a residual molten metal, an apparent volume of the residual molten metal in the furnace is derived from the discharge molten metal stop inclination absolute angle. A weight of the residual molten metal in the furnace is calculated by multiplying this apparent volume by the specific gravity of the molten metal and the correction coefficient (k) and displayed 18. Accordingly, the weight of the residual molten metal in the furnace is measured indirectly, a zero point adjustment corresponding to a tare weight varied as time elapses is not required, and the furnace can be operated suitably.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for measuring the weight of remaining metal in an electric furnace such as an induction melting furnace for melting metals such as cast iron and non-ferrous metals.

(Prior art) Conventionally, the method of measuring the weight of remaining metal in the furnace in this type of electric furnace is to measure the total weight of the furnace with a load cell, and then subtract the tare weight of the furnace from the total weight of the furnace. hot water mold t
The method of directly determining ``was generally adopted.

A representative example of this conventional measurement method will be described in detail with reference to FIG. 3.

The furnace body support frame 3 is pivotally attached to the column 2, and the pillars 6Kl:l- are installed on both sides of the furnace body 5, which can be tilted around the rotation fulcrum 4.
A docel 7 is arranged to receive the entire weight of the furnace under three-point support of the ficy docel 7 and the tilting fulcrum 4.
By adjusting the zero point of the instruction display section 8, the weight of the remaining hot metal in the furnace was to be measured and displayed by subtracting the Hirobukuro weight of the nine furnaces. Alternatively, as another method of arranging the load cells 7, four a-cells 7 are arranged at the lower part of the furnace body 5, and the weight of the remaining molten metal in the furnace is measured by adjusting the zero point of the instruction display section 8, as in the above example. It was supposed to be displayed.

By the way, the conventional method of directly determining the type i of remaining metal in the furnace by adjusting the tare weight of the furnace at the zero point has the following problems.

(1) The tare weight of a furnace changes over time due to wear and tear of the furnace wall lining material. This causes a shift in the zero point, so it is necessary to properly measure the tare weight of the furnace and readjust the zero point.

12) If you are working continuously day and night, measuring the tare weight of the furnace and readjusting the zero point will not work. From this,
The instruction display section 8 will display an inaccurate instruction value,
Errors occurred in the calculation of the temperature rise of the molten metal, which hindered furnace operation management such as molten metal temperature rise control and composition control.

(3) From the perspective of earthquake countermeasures, in the case of a type that measures the weight of remaining metal in the furnace by receiving the entire weight of the furnace under three-point support of the tilting fulcrum 4 and two rotors, Because the entire IT is not measured, the error is extremely large (±5 to 10 inches) and is not appropriate as furnace operation management data.
When testing using standard weights due to three-point support,
Errors occur due to changes in the position of the center of gravity, making it difficult to test pigeons.

(Problems to be Solved by the Present Invention) As described above, in the conventional method of directly measuring the weight of remaining metal in the furnace by adjusting the tare weight of the furnace at the zero point of the indicator display section 8, Due to the fact that the tare weight of the furnace changes over time, there have been many problems in managing the operation of the furnace.

A technical object of the present invention is to provide a method for measuring the weight of remaining metal in a furnace that is not affected by the tare weight of the furnace which changes over time.

(Friendly Means for Solving Problems) Ninth to achieve this technical problem, in the present invention,
Instead of adhering to the basic idea of directly measuring the weight of the remaining hot metal in the furnace, we decided to change the idea and indirectly measure the weight of the hot metal remaining in the furnace. Specifically, first, the volume in the furnace occupied by the remaining metal at each tilt angle of the furnace body at the time of constructing the furnace lining (hereinafter referred to as the standard volume of the remaining metal) is determined.

Next, during operation, the absolute tilting angle at the start of tapping and the absolute tilting angle at the stop of tapping are detected, and the apparent volume of tapped water is calculated from the standard volume of remaining hot water at the taping start tilting supply angle and the taping stop tilting absolute angle. is calculated, and the apparent weight of the hot water 01 is obtained from this apparent volume of the hot water and the specific gravity of the bath.

On the other hand, the actual weight of hot water @ (hereinafter, actual weight of hot water G1
That's what it means. ) to measure.

A correction coefficient =GL/Crs is determined from this actual weight G1 of tapped water and the apparent weight tGK' of tapped water.

This correction coefficient is a coefficient that corrects the volume inside the furnace when the furnace lining was constructed, to the actual volume inside the furnace, which changes over time due to damage to the lining material, etc. This is done by multiplying the apparent weight of the remaining molten metal obtained from the apparent volume of the remaining molten metal at the angle and the specific gravity of the molten metal by a correction coefficient K to obtain the weight of the remaining molten metal in the furnace.

(Function) According to the method for measuring the weight of the remaining molten metal in the furnace according to the present invention, the weight of the remaining molten metal in the furnace can be obtained indirectly without depending on the weight of the furnace glutinous bag. The value is not affected by the tare weight of the furnace.

(Example) Below, an example of j according to the present invention will be described based on the drawings. First, a description will be given of the equipment used to carry out the present invention. The same elements as those of the conventional induction melting furnace described above are given the same reference numerals and their explanations will be omitted. A device 10″f: shown in FIG. 1 is a device used to carry out the method, and an arcuate rack gear 11 centered around a tilting fulcrum 4 is fixed to the furnace body support frame 3.

On the other hand, an absolute angle detection type rotary encoder 12 is fixedly installed on the furnace body support column 2 facing the rack gear 11. It is fixed to the shaft of this a-tary encoder 12, and the nine pinion gear meshes with the rack gear 11. The shaft of the rotary encoder 12 is rotated by the tilting of the furnace body 5, and the absolute tilt angle of the furnace body 5 is detected.

A hot water tap detection means 14 such as a phototube is provided at the hot water tap 13 of the furnace body 5 . The tapping detection means 14 detects the start of tapping of molten metal from the tapping port 13 and the termination of tapping.

On the other hand, a scale 16 is attached to the crane 15 for tapping and ripping, and this scale 916 is used to measure the actual weight of the tapped hot water.

By the way, the arithmetic unit 17 such as a microcomputer has
Data of the standard volume of remaining metal at each tilt angle of the furnace body 5 during furnace lining furnace construction is stored, and the detection means 14
From the absolute tap start tilt angle and tap stop tilt absolute angle detected by the rotary encoder 12 at the start and stop of tap tap detected by Then, multiplying this by the specific gravity of the molten metal to calculate the apparent weight of the tapped water, 01°, and what is the apparent weight of the tapped hot water, 01°? From the actual weight GK of Kudeyu measured by 716, Gu/Gt
Calculate the correction coefficient K, which is the ratio of Multiply by the coefficient k to calculate the total weight of remaining metal in the furnace, and display on the display 18
The weight value of the remaining metal in the furnace is displayed.

Next, the calculation method of the microcomputer etc. will be explained based on the flowchart shown in FIG.

First, in step 10, the basic data of the furnace volume, such as the diameter of the furnace and the height to the tap hole at the time of constructing the furnace lining, is input, and in step 20, the clay scale 16 is used to measure the volume for tapping. Import the tare weight of the rib.

In step 30, the absolute tilt angle of the furnace body 5 is acquired by the a-tary encoder 12, and the tapping start tilt angle is stored by the tapping detection means 14 at the time when tapping is started.

In step 40, when the furnace body returns (stopping of tapping) is detected by the tap detection means 14, and the absolute tilting angle of tap stop at that time is stored.

In step 50, the apparent weight of tapped metal 01° is calculated from the furnace internal dimensions, the absolute tapping start tilting angle, the taping stop tilting absolute angle, and the specific gravity of the molten metal, and in step 60, the actual weight of tapped metal, that is, the actual weight G1 Step 70
Then, the correction coefficient for the volume inside the furnace due to wear and tear on the furnace wall, etc. is = G1/
Find Gl°.

In step 80, the apparent volume of the remaining molten metal in the furnace is calculated from the absolute angle at which the tap stops, and in step 90, the apparent volume of the remaining molten metal in the furnace is multiplied by the product 'F - specific gravity of molten metal and corrected 1,000 K. The weight G2 is calculated and displayed on the display 18.

In step 100, it is determined whether or not the measurement is to be stopped, and if the measurement is to be continued, steps can be repeated from step 20.

(Effects of the Invention) As is clear from the above explanation, according to the present invention, the weight of remaining metal in the furnace is measured by changing from the conventional direct method to an indirect method, so that the weight of the remaining metal in the furnace changes over time. There is no need to perform zero point adjustment corresponding to the tare weight of the furnace. This makes it possible to solve the conventional problems in furnace operation management caused by the deviation of the zero point, and to perform appropriate furnace operation while accurately measuring the weight of remaining metal in the furnace.

[Brief explanation of the drawing]

Figure 1 is a side view of the device used to demonstrate the present invention;
The figure is a 70-chart of an embodiment of the present invention, and FIG. 3 is a side view of the apparatus in a conventional method. 4...Furnace tilting fulcrum 5...Furnace body 11...Rack gear 12...Rotary encoder 14...
Hot water detection means 16... Clay scale 17...
Arithmetic unit patent applicant Toyota Motor Corporation Figure 3 Figure 2

Claims (1)

[Claims] (1) Calculate the standard volume inside the furnace at the time of furnace lining furnace construction, and calculate the apparent volume of tapped water from the absolute tilting angle of the furnace body at the start of tapping the furnace, the absolute tilting angle of the furnace body at the time of stopping tapping, and the standard volume inside the furnace. Then, the apparent volume of tapped water is multiplied by the specific gravity of the molten metal to obtain the apparent weight of tapped water G_1°, and the actual weight of tapped hot water G_1 and the apparent tapped weight G_1° are calculated.
Calculate the correction coefficient K=G_1/G_1° from the above, calculate the apparent volume of the remaining molten metal from the absolute angle of inclination of the furnace body at the time of stopping the tapping and the standard volume in the furnace, and add the specific gravity of the molten metal and the correction coefficient to the apparent volume of the remaining molten metal. A method for measuring the weight of remaining hot metal in an electric furnace, which measures the weight of hot metal remaining in the furnace by multiplying by K.