JPH08303967A - Molten metal leakage sensing method for channel type induction furnace and molten metal leakage sensing device - Google Patents

Abstract

PURPOSE: To perform a molten metal leakage sensing both between a protection cylinder and a runner and between the runner and an outer wall by a method wherein a DC current voltage is applied between the protection cylinder and a sensing electrode in the runner and between the runner sensing electrode and the outer wall, respectively, and a current value between each of them is measured. CONSTITUTION: A coil 20 is wound around an iron core 10 and then a protection cylinder 30 made of SUS is fixed around the coil 20. A runner 40 for holding molten metal 41 enclosed by stamp materials 50, 55 is arranged between the protection cylinder 30 and an outer wall 60 made of SUS covering the protection cylinder 30. A DC voltage is applied between the protection cylinder 30 and a sensing electrode 41 in a runner 40 and between the sensing electrode 42 in the runner 40 and the outer wall 60 from a DC power supply of a sensing device 120 through a changing-over device by lead wires 64, 65 and 66. With such an arrangement as above, it becomes possible to detect a value of current flowing through the stamp materials 50, 55 forming the runner 40 with the sensing device 120, resulting in that a molten metal leakage and its tendency can be judged without error.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten metal leak detection method and apparatus for a channel type induction furnace.

[0002]

2. Description of the Related Art A conventional leak detection device will be described with reference to the drawings. In FIG. 4, which is a cross-sectional view of a main part of the molten metal leak detection device of the induction furnace, a coil 20 is provided around the iron core 10, and a protective cylinder 30 made of SUS is provided around the coil 20.
And the molten metal 4 surrounded by the stamp materials 50 and 55 between the protective cylinder 30 and the SUS outer wall 60 covering the protective cylinder 30.
1 is provided with a runner 40 for holding 1, and a detection electrode 42 is provided on the runner 40 to form a leak detection device in an induction furnace. Here, the molten metal 41 passing through the runway 40 is detected by the detection electrode 42.
The protective cylinder 30 is connected to the ground fault detection device 62 and is grounded by the ground wire 61 via.

For example, the stamp material 5 forming the runner 40
It is assumed that a crack 51 is generated at 0 and a molten metal leak occurs. If the molten metal 41 flowing through the runner 40 reaches the protective cylinder 30 through the crack 51, the molten metal 4 that has soaked into the crack 51 because the runner 40 and the ground fault detection device 62 are grounded.
An electric current is detected by the ground fault detection device 62 via 1 and it can be detected that there is molten metal leakage.

[0004]

In the hot-water leak detecting device having the above-mentioned structure, when a crack 51 occurs in the stamp material 50 between the protective cylinder 30 and the runner 40, and a hot-water leak occurs, a ground fault detecting device 62 is provided. If the molten metal does not directly reach the detection electrode 42, the molten metal leak cannot be detected, and it is difficult to know the progress of the molten metal leak. If the stamp material 55 between the runner 40 and the outer wall 60 leaks,
The leak could not be detected.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a detection method and an apparatus therefor capable of proactively knowing the progress of molten metal leakage.
It is another object of the present invention to provide a detection method and apparatus capable of separately detecting leaks between the protective cylinder and the runner, between the runner and the outer wall, and between the protective cylinder and the outer wall.

[0006]

According to the present invention, a coil wound around an iron core and a protective cylinder surrounding the coil are attached, and a stamp material surrounds the protective cylinder and an outer wall covering the protective cylinder. Using a leak detector with a runner for holding the molten metal, apply a DC voltage from the DC power source of the detector to the protective cylinder, the sensing electrode of the runner, and the outer wall through a switch. A method for detecting leakage of molten metal in a channel-type induction furnace, in which a current value is measured by a measuring device of the above-mentioned detection device to detect leakage of molten metal held in a runner. Further, a coil wound around the iron core and a protective cylinder that surrounds the coil are attached, and a runner is provided between the protective cylinder and an outer wall that covers the coil to hold molten metal surrounded by a stamp material, In this hot water leak detection device in which a detection electrode is provided in the runner, a DC voltage is applied from the DC power source of the detection device to the protection cylinder, the detection electrode of the runner, and the outer wall by applying a DC voltage to the protection cylinder. Hot water in a channel-type induction furnace configured to measure the current value of the stamp material between the molten metal, between the molten metal and the outer wall, and between the protective cylinder and the outer wall by the measuring device of the detection device, and detect the leakage of the molten metal in the induction furnace. This is a leak detection device.

[0007]

[Function] Both the molten metal leak can be detected by applying a DC voltage between the protective cylinder and the runner detecting electrode and between the runner detecting electrode and the outer wall and measuring the current value between them. A hot water leak detection method can be provided. Further, it is possible to provide a device capable of separately detecting the leakage of hot water between the protective cylinder and the outer wall by the switch. Further, by comparing the measured current value with the model, it is possible to provide a device capable of detecting the progress of the molten metal leak.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, which shows a sectional view of a molten metal leak detecting device in a channel-type induction furnace, the molten metal leak detecting device is provided by winding a coil 20 around an iron core 10 as in the conventional example, and is made of SUS around the coil 20. The protection cylinder 30 is attached, and a runner 40 for holding the molten metal 41 surrounded by the stamp materials 50 and 55 is provided between the protection cylinder 30 and the SUS outer wall 60 covering the protection cylinder 30. The DC power supply 7 of the detection device 120 is provided between the protective cylinder 30 and the detection electrode 42 of the runner 40, and between the detection electrode 42 of the runner 40 and the outer wall 60.
Direct current voltage is applied from 0 to the lead wires 64, 65 and 66 through the switch.

FIG. 2 shows a circuit diagram of an example of the detecting device. That is, by switching the switching devices 80 and 85 of the detection device 120, the detection device 120 is moved to the protection cylinder 30 and the detection electrode 42 of the runner 40, the detection electrode 42 of the runner 40 and the outer wall 60, and the protection cylinder 30 and the outer wall 60, respectively. DC voltage is applied from the DC power source 70 of No. 1 through the lead wires 64, 65 and 66,
It is possible to individually detect the current values flowing through the stamp materials 50 and 55 forming the runner 40 by the measuring device 110 of the detection device 120. That is, when both the switching devices 80 and 85 are opened, the resistances 90 and 10 between the protective cylinder 30 and the outer wall 60.
The current can be measured by the measuring device 110 via 0,
When the switch 80 is opened and the switch 85 is closed, the current flowing through the resistance 90 between the protective cylinder 30 and the detection electrode 42 of the runner 40 can be measured by the measuring device 110, and the switch 80 is closed. When the switching device 85 is opened, the current flowing through the detection electrode 42 of the runner 40 and the resistance 100 of the outer wall 60 can be measured by the measuring device 110. Therefore, it is possible to separately detect the current values based on the resistances 90 and 100 of the stamp materials 50 and 55 inside and outside the runner 40.

Incidentally, the resistance of the stamp material 50 is 100 k.
Ω, thickness 200 mm, applied voltage 48 V, the normal current value is about 0.48 mA, when the applied voltage is constant, when the measured current changes to 0.96 mA, the resistance of the stamp material 50 is about 50kΩ, 40 to 100 runners
It can be inferred that the leakage of water has progressed up to mm.
When the measured current changes to 9.6 mA with the applied voltage kept constant, the resistance of the stamp material 50 becomes about 5 kΩ, and it is presumed that the leakage of the molten metal is progressing from the runner 40 to 10 mm. It is determined that the material 50 needs to be stamped again.

FIG. 3 is a graph showing the relationship between the measured current value and the resistance value of the stamp material. That is, the measuring device 1 of the detection device 120
The higher the current value detected in 10, the stamp material 50, 55
The resistance value of has decreased. It is possible to know the degree of progress of the molten metal leak by measuring the current value while keeping the applied DC voltage constant and comparing it with known data. In addition, the degree of progress of molten metal leakage can be known by examining the increase in the current value.

[0012]

As described above, according to the molten metal leak detection method for a channel type induction furnace of the present invention, the progress of molten metal leakage of the channel type induction furnace is grasped as a change in the resistance value from the measurement of the current value, which is extremely effective. It is possible to measure reliably and easily. Further, the detecting device can be separately detected by a simple device with a switch, and it is possible to surely judge the leakage of water and its tendency.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a molten metal leak detection device according to an embodiment,

2 is a circuit diagram of the detection device of FIG. 1,

FIG. 3 is a graph showing the relationship between the stamp material resistance and the measured current,

FIG. 4 is a sectional view of an essential part of a conventional molten metal leak detection device.

[Explanation of symbols]

 10 iron core 20 coil 30 protective cylinder 40 runner 41 molten metal 42 detection electrode 50,55 stamp material 60 outer wall 64,65,66 lead wire 70 DC power source 80,85 switch 90,100 resistance of stamp material 110 measuring device 120 detector

Claims (2)

[Claims] 1. A runner having a coil wound around an iron core and a protective cylinder surrounding the coil attached thereto, the runner being surrounded by a stamping material and holding a molten metal between the protective cylinder and an outer wall covering the coil. By using the molten metal leak detection device provided with the above, a DC voltage is applied between the protective cylinder, the detection electrode of the runway and the outer wall from the DC power source of the detection device through a switch, and the measuring device of the detection device is used. A method for detecting leaks in a channel-type induction furnace, characterized in that a current value is measured and a leak of molten metal held in a runner is detected. 2. A runner which is provided with a coil wound around an iron core and a protective cylinder which surrounds the coil, and which holds a molten metal surrounded by a stamp material between the protective cylinder and an outer wall which covers the coil. In the hot water leak detection device in which a detection electrode is provided in this runner, a DC voltage is applied from the DC power supply of the detection device to the protective cylinder, the detection electrode of the runway, and the outer wall via a switch, The current value of the stamp material between the protective cylinder and the molten metal, between the molten metal and the outer wall, and between the protective cylinder and the outer wall is measured by the measuring device of the detection device, and the leakage of the induction furnace is detected. A leak detection device for a channel-type induction furnace.