JP2002148099A - Molten metal level sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molten metal level sensor which can measure the upper surface position of various molten metals without being affected by adhesion of the metal or oxides thereof or the heat of the molten metal. SOLUTION: In a fine ceramic protective tube which is not affected by adhesion of the molten of a metal being measured or its oxides and the heat of the molten metal, a transmission coil and a receiving coil of sine wave are disposed. The measuring unit is inserted into the molten metal and the upper surface position of the molten metal is measured utilizing a transmission wave from the transmission coil located above the upper surface of the molten metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for digitally or digitally detecting the level of a molten metal in a melting furnace for molten metal, a molten metal metering pump, a furnace for holding molten metal, that is, an upper surface position, which is mainly used for casting. Relates to an improvement of a level sensor for molten metal which displays in any analog manner.

[0002]

2. Description of the Related Art Various types of sensors, such as a float type, an ultrasonic type, a laser type, or an electric capacity type, are used as sensors for detecting the upper surface position or level of a molten metal in a metal melting furnace, a molten metal metering pump, or the like. Has been proposed.

[0003]

The above-mentioned float type sensor has problems such as an increase in measurement error due to adhesion of molten metal or oxide and an increase in measurement error due to heat due to the float material. The sensor described above has a large measurement error in a high-temperature atmosphere, which makes it difficult to correct, and also has a problem that the ultrasonic sensor cannot be exposed to high temperatures. Also, the laser type sensor has a problem that the laser sensor cannot be exposed to a high temperature, and the capacitance type sensor is sensitive to the influence of the molten metal film or the oxide film and the measurement error becomes large.

For this reason, the present invention provides a method for accurately and easily melting a molten metal or an oxide film without affecting the measured value or the sensor itself due to the measurement in a high-temperature atmosphere. It is an object of the present invention to provide a sensor capable of measuring a metal surface level.

[0005]

In order to solve the above-mentioned problems, the present invention provides a molten metal level sensor having the following configuration. In other words, a sine-finished bobbin made of fine ceramics and placed in a long-bottomed bottomed protective tube made of fine ceramics that withstands the melting temperature of the metal to be measured and does not cause adhesion of the metal or its oxide. The transmitting coil for transmitting the wave and the receiving coil for receiving the sine wave were wound and arranged in a double spiral shape with the same coil average diameter and the same coil pitch shifted by a half pitch. Then, both ends of the transmission coil are connected to a sine-wave transmitter, and both ends of the reception coil are connected to the sine-wave receiver, and the long cylindrical protection tube containing the transmission coil and the reception coil is vertically moved. The metal melt is inserted from above the upper surface into the melt to a depth that covers the fluctuation range of the upper surface of the molten metal that fluctuates, and the voltage output terminal of the receiver is
The structure is such that it is connected to a numerical display at the top of the metal melt.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a skeleton diagram showing an example of a level sensor according to the present invention as a partial cross section. The protective tube is made of fine ceramics and has a long cylindrical shape with a bottom. 1, a bobbin 2 also made of fine ceramics is arranged, and a transmitting coil 3 for transmitting a sine wave and a receiving coil 4 for receiving a sine wave transmitted from the transmitting coil 3 are provided on the outer surface of the bobbin 2. Are wound in a double spiral shape with the same coil average diameter R and the same coil pitch P shifted by half a pitch.

Both ends 5 and 6 of the transmitting coil 3 are connected to a sine-wave transmitter 7, and both ends 8 and 9 of the receiving coil 4 are connected to a sine-wave receiver 10.
The zero power output terminal 11 is connected to a numerical operation display 14 that displays the position of the upper surface 13 of the molten metal 12 based on the input from the receiver 10.

The protection tube 2 in which the bobbin 2 on which the transmission coil 3 and the reception coil 4 are wound is mounted on the protection tube 2. 4 is inserted from the upper surface of the molten metal to a depth that can be completely covered, and the position is fixed.

The transmitter 7 has a frequency of 100 KHz to 500 KH.
z, and transmits the sine wave to the transmitting coil 3 so that the receiver 10
Receives a sine wave by the receiving coil 4, converts the induced output as a cosine wave into a voltage, and inputs the converted voltage to the numerical operation display 14.

FIGS. 2, 3 and 4 show the transmitting coil 3 wound on the bobbin 2 in the protective tube 1 when the upper surface 13 of the molten metal 12 is gradually lowered as the molten metal 12 is taken out. The positional relationship with the receiving coil 4 is schematically shown.

Since the sine wave (line of magnetic force) transmitted from the transmitting coil 3 is absorbed by the molten metal 12, only the sine wave transmitted from the transmitting coil 3 located above the upper surface 13 of the molten metal 12 receives the sine wave. 4.

The present invention makes use of this principle, and FIG.
In the state shown in (1), since the transmitting coil 3 located above the upper surface 13 of the molten metal 12 does not exist, it is displayed on the numerical operation display 14 that the molten metal 12 is at the highest level, and the consumption of the molten metal 12 is reduced. Transmission coil 3 according to advance
However, since the height located above the metal melt 12 due to the upper surface 13 is sequentially increased to H1 and H2, the transmission coil 3 having the heights of H1 and H2 transmits the sine wave, thereby causing the upper surface 3 to become higher.
Are displayed on the numerical operation display 14 continuously.

[0013]

According to the present invention, a sine wave transmitting coil and a receiving coil are disposed in a fine ceramics protection tube having at least heat resistance and non-adhesiveness to a metal to be measured and its oxide. The transmitter, receiver, and numerical display corresponding to each coil can be installed in a place where there is no influence of heat from the molten metal.The transmission coil and the reception coil are heat-resistant fine ceramic bobbins. Since these coils are wound in the protective tube and disposed in the protective tube, these coils are not affected by heat, and have an effect of accurately measuring the level of the upper surface of the molten metal for a long period of time.

Since the sine wave transmitted from the transmitting coil in the molten metal is used as the measuring means, the sine wave transmitted from the transmitting coil located in the molten metal is absorbed by the molten metal and received by the receiving coil. Since only the sine wave transmitted from the transmitting coil located above the upper surface of the molten metal is received by the receiving coil and converted into a measured value, fine and accurate measured values can be continuously obtained. Also have.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram showing a cross section of a main part of an embodiment.

FIG. 2 is an explanatory diagram of a positional relationship between a transmitting coil and a receiving coil when the upper surface of a molten metal occupies the highest position.

FIG. 3 is an explanatory diagram of a positional relationship between an upper surface of the molten metal, a transmitting coil, and a receiving coil when the molten metal is slightly reduced.

FIG. 4 is an explanatory diagram of a positional relationship between an upper surface of the molten metal, a transmitting coil, and a receiving coil when the molten metal is exhausted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Protective tube 2 Bobbin 3 Transmitting coil 4 Receiving coil 5, 6 Both ends of transmitting coil 7 Transmitter 8, 9 Both ends of receiving coil 10 Receiver 11 Power output end 12 Molten metal 13 Top surface 14 Numerical operation display

Continuation of the front page F term (reference) 2F014 AB03 AC06 EB01 2F073 AA01 AB04 BB02 BC01 CC02 CD02 DD01 DE02 FF03 GG05

Claims (1)

[Claims] 1. The melting temperature of at least the metal disposed in a long-bottomed protective tube made of fine ceramics that withstands the melting temperature of the metal to be measured and does not cause adhesion of the metal or its oxide. The transmitting coil for transmitting a sine wave and the receiving coil for receiving the sine wave are the same coil average diameter on a bobbin made of fine ceramics that can withstand
The same coil pitch is wound and arranged in a double helix shifted by half a pitch, both ends of the transmitting coil are connected to a sine wave transmitter, and both ends of a receiving coil are connected to the sine wave receiver. And the long cylindrical protection tube containing the transmitting coil and the receiving coil is inserted into the molten metal from above the upper surface of the molten metal to a depth that covers the fluctuation range of the upper surface of the molten metal that moves vertically. A level sensor for molten metal in which the voltage output terminal of the receiver is connected to a numerical display at the top of the molten metal.