JPS6199092A - Method of measuring weight of residual molten metal in electric furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for measuring the residual lifting weight f's in an electric furnace such as an induction melting furnace for melting metals such as cast iron and non-ferrous metals. .

(Prior art) Remaining molten metal M in this type of electric furnace, J1)
The conventional method is to measure the total weight of the furnace using a load cell.
Subtracting the tare weight of the furnace from its total furnace weight: Thus,
Generally, a method was used to directly determine the weight of the remaining metal in the furnace.

A representative example of this conventional measurement method is shown in Figure 3.
To be more specific, a furnace support frame 6 is pivotally attached to a furnace support column 2 erected on a base 1), and the support columns 6 are installed on both sides of a furnace body 5 that can be tilted about a tilting fulcrum 4. A load cell 7 is disposed at the top, and the entire furnace weight tf is received under the three-point support of the load cell 7 and the tilting fulcrum 4, and the tare weight of the furnace is subtracted by zero point adjustment of the indication display section 8 of the load cell 7. The weight of the remaining hot water was to be measured and displayed. Or load cell 7
Another arrangement method is to arrange four rotors at the bottom of the furnace body 5, and measure and display the weight of the remaining metal in the furnace by adjusting the zero point of the instruction display section 8, as in the previous example. was.

By the way, in the conventional method of directly determining the weight of remaining metal in the furnace by adjusting the tare weight of the furnace at the zero point,
There were 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.

(2) Under continuous beam operation day and night, it is not possible to measure the tare weight of the furnace and readjust the zero point. From this,
The instruction display section 8 will display an inaccurate instruction value,
Errors occurred in calculating the temperature of the molten metal, which caused problems in operational management such as molten metal temperature 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 total weight of the furnace under three-point support of the tilting fulcrum 4 and two load cells 7, the total weight of the furnace is measured by the rotor self. Because the data is not measured, the error is extremely large at ±5 to 10%, making it unsuitable as operational management data. Furthermore, because of the three-point support, when testing using standard weights, errors are likely to occur due to fluctuations in the center of gravity, making testing difficult.

(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 operational management.

The technical problem 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.

(Means for solving the problem) In order to achieve this technical problem, the present invention includes the following:
Instead of adhering to the conventional basic idea of directly measuring the weight of the remaining metal in the furnace, we decided to change the idea and measure the weight of the remaining metal in the furnace indirectly. Specifically, first, each inclination f of the furnace body at the time of constructing the furnace lining
In addition to finding the volume occupied by the remaining metal at the il angle, the wear correction coefficient K for each passing tonnage of the furnace wall lining is investigated and set.

Next, during operation, the absolute tilting angle at the start of tapping and the absolute tilting angle at the time of stopping the tapping are detected, and based on the absolute tilting angle at the start of tapping and the absolute tilting angle at the stop of tapping, and the already determined initial set furnace volume. The tapping volume is calculated, and the tapping volume is multiplied by the specific gravity of the molten metal and the furnace wall wear correction coefficient K for the passing tonnage to calculate the tapping weight, and the passing tonnage is integrated.

On the other hand, from the absolute tilting angle at which the tap stops, calculate the corresponding initial set bath volume in the furnace, and multiply this initial set boil tank volume by the wear correction coefficient for each passing tonnage and the specific gravity of the molten metal. It is also possible to calculate the weight of remaining hot water.

However, according to the method for measuring the weight of the remaining metal in the furnace according to the present invention, the weight of the remaining metal in the furnace can be indirectly obtained without using the tare weight of the furnace. The residual metal weight value is not affected by the tare weight of the furnace.

(Example) Below, one example of the present invention will be explained based on the drawings. First, an explanation will be given of the apparatus used to carry out the present invention. Elements that are the same as those in the furnace a are given the same reference numerals and their explanations will be omitted. FIG. 1 shows an apparatus 10 used for carrying out the present invention, in which an arcuate rack gear 1 centered around a tilting fulcrum 4 is mounted on a furnace body support frame 3.
) is permanently installed.

On the other hand, an absolute angle detection type rotary encoder 12 is fixedly installed on the furnace body support 2 facing the rack gear 1), and a pinion gear fixed to the shaft of this rotary encoder 12 meshes with the rack gear 1). 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 disposed at the tap tap 15 of the furnace body 5 . The tapping detection means 14 detects the start and stop of tapping molten metal from the tapping port 16.

By the way, the calculation unit 15 such as a microcomputer stores data such as the inside dimensions of the furnace lining at the time of furnace construction and the wear correction coefficient K for each passing tonnage of the furnace wall lining obtained by investigation. At the start and stop of tapping detected by the tapping detection means 14, the specific gravity of the molten metal and the passing ton are calculated from the tapping start tilting absolute angle and tapping stop tilting absolute angle of the furnace body 5 detected by the rotary encoder 12. In addition to calculating the visiting weight by multiplying the number by the furnace wall wear correction coefficient K and integrating the passing tonnage, the initial setting in-furnace bath volume is calculated from the absolute angle of tap stop tilting, and the initial setting in-furnace bath volume is , the weight of the remaining metal in the furnace is calculated by multiplying the loss correction coefficient for each passing tonnage by the specific gravity of the molten metal, and is displayed on one display i61.

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

First, in step 10, initial settings such as the internal dimensions of the furnace lining at the time of constructing the furnace are performed.

In step 20, the absolute tilting angle to start tapping, and in step 30, the absolute tilting angle to stop tapping are detected by the tapping detection means 14 attached to the tapping port 15 and the rotary encoder 12, and in step 40, the volume in the furnace corresponding to the weight of tapped metal is calculated. The weight of tapped metal is calculated based on the loss correction coefficient for each tonnage passed through the furnace and the specific gravity of the molten metal, and the tonnage passed is integrated. This wear correction coefficient has a value of 1 at the start.

In step 50, a loss correction coefficient K for each passing tonnage is calculated based on a previously researched and set method for correcting changes in the volume inside the furnace due to wear and tear on the furnace wall lining when the passing tonnage increases.

In step 60, the volume of the bathhouse in the furnace is calculated from the absolute angle of inclination to stop tapping, and in step 70, the wear correction coefficient K(l
! : Calculate the weight of the remaining metal in the furnace from the specific gravity of the molten metal, and proceed to step 8.
0, the weight of the remaining metal in the furnace is displayed on the display 16. step,
te'? Then, it is determined whether the measurement is to be stopped or not, and if the measurement is to be continued, the process returns to step 20.

(Effects of the Invention) As is clear from the above explanation, according to the present invention, the weight of the remaining metal in the furnace is measured by an indirect method instead of the conventional direct method. There is no need to perform zero point adjustment in response to the changing tare weight of the furnace. From this, it is possible to eliminate the problems in furnace operation management caused by the deviation of the conventional zero point, and to operate the furnace without SfA under an accurate measurement of the amount of residual metal M in the furnace. be able to.

[BRIEF DESCRIPTION OF THE DRAWINGS] No. 1- is a side view J of the apparatus used for carrying out the present invention;
The figure is a flowchart of an embodiment of the present invention, and FIG. 3 is an explanatory diagram of an apparatus in a conventional method. 4...Furnace tilting fulcrum, 5...Furnace body, 1)...-Rack gear, 12--Rotary encoder, 14...Made-out detection means, 15...Calculating unit Fig. 3

Claims (1)

[Claims] (1) Furnace lining Determine the volume inside the furnace at the time of furnace construction, determine the furnace wall wear correction coefficient K for each tonnage passing through the furnace, and calculate the absolute tilting angle of the furnace body at the start of tapping and the tilting of the furnace body at the time of stopping tapping. Calculate the tapping volume from the absolute angle and the volume inside the furnace, multiply the tapping volume by the specific gravity of the molten metal and the furnace wall wear correction coefficient K for the passing tonnage to obtain the tapping weight, and integrate the passing tonnage; The volume of the remaining molten metal in the furnace is calculated from the absolute stop tilt angle and the volume in the furnace, and the volume of the remaining molten metal in the furnace is multiplied by the furnace wall wear correction coefficient K corresponding to the passing tonnage and the specific gravity of the molten metal. How to measure the weight of remaining hot water in an electric furnace.