JPH05322627A - Molten level measuring method - Google Patents

Abstract

PURPOSE:To measure the level of molten iron to be fed into a molten vessel accurately. CONSTITUTION:When the level 4 of molten iron 3 to be fed into a molten vessel 1 is measured, a level gauge 2 being set with a temperature measuring metal wire 11 constituting a closed conducting circuit is placed in a ceramic protective pipe 11 having lower open end and immersed into the molten iron 3. Level of molten iron 3 is measured based on variation of electrical resistance between the metal wires 11 caused by short circuit thereof through the level of the molten iron 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention supplies a molten material such as hot metal, molten steel and slag to a ladle such as a hot metal ladle, a molten steel ladle and a slag ladle, and a melt processing container (molten metal container) such as a torpedo car and a tundish. The present invention relates to a method for detecting the liquid level of the melt in the molten metal container.

[0002]

2. Description of the Related Art The hot metal tapped from a blast furnace is received by a hot metal ladle or a torpedo car, and the hot metal is refined into steel at a steelmaking plant. The molten steel is ladle, and the slag generated during refining is slag. It is received and transported by a pot.

It is important that the melt charged in the melt processing container in these series of steps is always kept at the same level in the processing container in view of its processability and workability. That is, the hot metal received by the torpedo car is sent to the next desulfurization step, and in the desulfurization step, the lance is lowered from above, and the desulfurization treatment of the hot metal is performed while blowing nitrogen (N2) gas together with the desulfurizing agent. If more than the specified amount is received, overflow due to N2 gas injection occurs, and if less than the specified amount is received, the lance for N2 gas injection does not reach the required depth in the hot metal and desulfurization is unsuccessful. Will be enough. In addition, when the molten material is received in a ladle such as a hot metal ladle, a molten steel ladle, and a slag ladle, and is transported, if the charging amount is small, 2 pots are combined into 1 pot, so-called combined hot water operation and transportation frequency increase, If the charge is high, there is a risk of overflow during transport.

[0004]

From the above viewpoints, attempts have been made so far to make the level of the molten material in the molten metal container constant. For example, the method of measuring the level of a molten material using radiation has a problem that it cannot be easily handled by an on-site worker because the management for handling the apparatus is strict. Further, in the melt level measuring method using the microwave distance measuring device disclosed in JP-A-61-57875 and JP-A-50-44279, there is a problem that a measurement error due to a coating on the melt surface is large. is there.

Further, Japanese Patent Publication No. 60-49686 and Japanese Patent Publication No. 1-42
In the case of the weight measurement shown in Japanese Patent No. 363, the equipment is very large and the equipment cost is high in a torpedo car, and
Even if the amount of pig iron received is constant, the level of the melt differs and the torpedo desulfurization varies due to the melting loss of the internal refractory due to the number of times the torpedo car is used. Therefore, there are many problems that rely on the visual inspection of the site worker, and even if the visual inspection is performed, a large error occurs in the accuracy, and there is a problem that the working environment is bad due to high heat, dust and the like. An object of the present invention is to provide a technique for solving the above-mentioned problems and capable of constantly and safely detecting a desired melt level in a molten metal container.

[0006]

Means for Solving the Problems The present invention for achieving the above-mentioned object is to measure a liquid level of a molten metal supplied to a molten metal container in a ceramic protective tube having a lower end opened in the molten metal. Immerse the level meter with the wire set, and measure the liquid level of the molten metal based on the change in electrical resistance between the metal wires due to the temperature measuring metal wire of this level meter being short-circuited through the molten metal surface. This is a characteristic method for measuring the liquid level of molten metal. In the above measuring method, it is preferable to correct the change in electric resistance due to the change in temperature of the temperature-measuring metal wire.

[0007]

According to the present invention, the temperature-measuring metal wire protected by the ceramic protection tube is immersed in the molten metal, the electric resistance of the metal wire is measured, and the distance to the liquid level of the molten metal is measured based on the change in the electric resistance. Will be able to measure accurately with the same measuring instrument repeatedly. As the temperature-measuring metal wire, Nichrome Ni-Cr (20%),
Tungsten W and the like are suitable for measuring the temperature of the molten metal.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic explanatory view of an apparatus showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a molten metal container, and a molten metal 3 in the molten metal container 1 has a ceramic protection tube with a lower end opened.
The lower part of the level gauge 2 in which a temperature-measuring metal wire 10 (here, nichrome is used as a metal wire) that constitutes an energized closed circuit is set in 11 is immersed to a predetermined depth.

A ring 8 is fixed to the upper part of the ceramic protection tube 10 by screwing a bolt 9 into the ring 8. The tip of an arm 7 is fixed to the ring 8 and the level meter 2 is fixed through the arm 7 to a predetermined level. It is designed to be held in depth.
Since the temperature-measuring metal wire 10 is protected by the ceramic protection tube 11, it is protected from bubbling of the molten metal surface and molten metal flow when the molten metal 3 is supplied into the molten metal container 1.

The temperature-measuring metal wire 10 is connected to the resistance measuring device 5 and constitutes an energization closed circuit, and measures changes in the electric resistance of the temperature-measuring metal wire 10. Reference numeral 6 denotes a calculator, which calculates the melt liquid level in the melt container 1 based on the change in the electrical resistance of the temperature-measuring metal wire 10. The temperature-measuring metal wire 10 may be a circuit that energizes only when it contacts the surface of the molten metal.

Next, the operation of the present invention will be described. When the molten pig iron 3 is supplied into the molten metal container 1, the liquid level 4 rises, but at this time, the temperature measuring metal wire set in the ceramic protection tube 11
10 is immersed in the hot metal 3 which penetrates from below. For this reason, the temperature-measuring metal wire 10 forming the energization closed circuit is short-circuited via the liquid surface of the hot metal 3, and the electric resistance of the temperature-measuring metal wire 10 changes. That is, as the liquid level 4 of the hot metal 3 rises, the temperature measuring metal wire 10
Since the short-circuited position becomes high, and the current path through the temperature-measuring metal wire 4 which constitutes a short closed loop circuit becomes gradually shorter, the electric resistance measured by the resistance temperature measuring device 5 becomes smaller.

The short-circuit position of the temperature-measuring metal wire 10, that is, the liquid level 4 level of the hot metal 3 is measured based on the amount of change in the electric resistance of the temperature-measuring metal wire 10. In addition, temperature measuring metal wire 10
Since the electric resistance value of is changed by the temperature, for example, a thermocouple (not shown) is immersed in the ceramic protective tube 11 to measure the temperature, and the temperature measurement result is calculated by the calculator 6 based on the temperature change. If the value is corrected, the liquid level of the hot metal supplied to the molten metal container 1 can be measured more accurately.
Table 1 shows a comparison between the actual measured liquid level of the hot metal supplied into the molten metal container and the measured liquid level measured using the same level meter according to the present invention.

[0013]

[Table 1]

According to the present invention, as shown in Table 1, the liquid level of the hot metal supplied to the molten metal container is accurately measured with an accuracy of 5% or less with respect to the actual measured value even if the same level meter is repeatedly used. It is clear that you can. In addition, although the case where the liquid level level of the hot metal is measured has been described in the above-mentioned embodiment, it goes without saying that the liquid level levels of various molten metals can be similarly measured.

[0015]

As described above, according to the present invention, the liquid level of the molten metal supplied into the molten metal container can be accurately measured. For this reason, it becomes possible to supply the molten metal so that the liquid surface level is convenient for treating various molten metal containers, and the processing efficiency of the molten metal is improved. Further, since the operation efficiency of the molten metal container is improved, it is possible to reduce the molten metal container.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 1 Molten Metal Container 2 Level Meter 3 Hot Metal 4 Liquid Level 5 Resistance Measuring Device 6 Computer 7 Arm 8 Ring 9 Bolt 10 Temperature Measuring Metal Wire 11 Ceramic Protective Tube

Claims (2)

[Claims] 1. When measuring a liquid level of a molten metal supplied to a molten metal container, a level gauge having a temperature-measuring metal wire set is immersed in the molten metal in a ceramic protective tube having an open lower end,
A method for measuring a liquid level of a molten metal, characterized in that the liquid level of the molten metal is measured based on a change in electric resistance between the metal wires when the temperature-measuring metal wire of the level meter is short-circuited through the liquid surface of the molten metal. . 2. The method for measuring the liquid level of a molten metal according to claim 1, wherein a change in electric resistance due to a change in temperature of the temperature-measuring metal wire is corrected.