JP2526341B2 - Measuring method of molten metal surface level with ultrasonic level meter - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates are those which relate to the measurement method of the molten metal liquid surface due to the ultrasonic level meter suitable for level measurement of the melt in the high melting furnace of dust generation amount at a high temperature.

[0002]

2. Description of the Related Art For example, in a high frequency melting furnace used for volume reduction of radioactive solid waste, it is desired to accurately grasp the level of the molten material in the furnace, but the atmosphere in the furnace is 15
Since the temperature becomes high at around 00 ℃ and the gas in the furnace contains a lot of dust, level measurement is not easy.
That is, although a level measuring instrument using a laser beam generally used for this kind of level measurement is suitable for detecting whether or not the level has reached a certain point, in addition to the large attenuation of the light amount due to dust, It is not suitable for detecting a continuously changing level over a wide range.

An ultrasonic level meter suitable for detecting a continuously changing level over a wide range has an installation temperature of about 0 to 50 ° C., and dust adheres to the ultrasonic sensor to function. It has been a conventional wisdom that it cannot be used for measuring the level of a melt in a furnace with such high temperature and high dust because it may lower the temperature.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and makes it possible to accurately measure the level of high dust in a furnace at high temperature with an ultrasonic level meter.
It was completed for the purpose of providing a liquid level measuring method .

[0005]

SUMMARY OF THE INVENTION The present invention, which has been made to solve the above-mentioned problems, provides an electrical connection to one end of an L-shaped waveguide.
The ultrasonic sensor is connected to the
Insert the other end of the tube into the furnace so that the distance from the molten metal surface can be adjusted.
When measuring the level of molten metal using the ultrasonic level meter
At the position where the purge air was blown between the waveguide and the ultrasonic sensor.
Position, the output is measured and the output is the most stable
Measure the level of the molten metal while blowing in purge air from the dead position.
It is characterized in that constant.

[0006]

The present invention will be described below in more detail with reference to the illustrated embodiments. In FIG. 1, 1 is a furnace wall of a high-frequency melting furnace, 2 is a crucible-shaped container installed therein, and 3 is a high-frequency heating coil. In this embodiment, for example, radioactive miscellaneous solid waste is intermittently charged into the container 2, is induction-heated by the high-frequency heating coil 3, and is melted at a high temperature of about 1500 ° C. In order to measure the level of this melt, the ultrasonic level meter of the present invention is installed on the ceiling portion of the furnace wall 1.

FIG. 2 is an enlarged view of a main part thereof, in which 4 is an L-shaped waveguide, and 5 is an ultrasonic sensor provided at the outer end thereof. The connecting portion between the ultrasonic sensor 5 and the waveguide 4 is electrically insulated. As shown in the figure, the L-shaped waveguide 4 is attached to the ceiling of the furnace wall 1 with the inner side of the furnace facing vertically downward so that ultrasonic waves can be emitted toward the liquid surface inside the container 2 described above. Is set to. The part attached to the furnace wall 1 is sealed by a gland packing 7 having a push screw 6.
The structure is such that the waveguide 4 can be slid up and down by loosening.

Reference numeral 8 is an ultrasonic sensor 5 on the outside of the waveguide 4.
Is a nozzle for blowing in purge air, which is provided at a position close to. In the present invention, by blowing the purge air into the inside of the waveguide 4 from the blowing nozzle 8, it is possible to prevent the in-furnace gas containing a large amount of dust from entering the inside of the waveguide 4, and the ultrasonic sensor 5 is installed. It is cooling. In general, when the purge air is blown into the waveguide 4 in this way, it naturally causes a disturbance to the ultrasonic sensor 5 and disturbs the output. However, in the present invention, this problem is avoided by providing the purge air blowing nozzle 8 at a blind position between the waveguide 4 and the ultrasonic sensor 5.

The dead position referred to here is a position at which the output of the ultrasonic sensor 5 is not affected even if air is blown into it. For example, as shown in FIG. The measurement shows that the output of the ultrasonic sensor 5 is stable within a certain range. Therefore, if the purge air blowing nozzle 8 is provided within this range, it is possible to prevent the in-furnace gas from entering the inside of the waveguide 4 without adversely affecting the ultrasonic sensor 5.

[0010]

[Operation] Using the ultrasonic level meter constructed in this way
In order to measure the liquid surface of the molten metal , ultrasonic waves oscillated from the ultrasonic sensor 5 are emitted to the liquid surface of the molten material in the furnace through the L-shaped waveguide 4, and the reflected wave is sensed. Although the level of the liquid surface is measured, since the L-shaped waveguide 4 is used, radiant heat from the high temperature gas in the furnace does not reach the ultrasonic sensor 5 directly. In addition, as described above, the waveguide 4 and the
By changing the blowing position of the purge air between the sound wave sensors 5,
Output to measure the dead position where the output is the most stable.
In advance, since the purge air is blown into the inside of the waveguide 4 from the dead position by the blowing nozzle 8, the furnace gas containing a large amount of dust is prevented from entering the inside of the waveguide 4. At the same time, the ultrasonic sensor 5 is cooled.
Moreover, the output of the ultrasonic sensor 5 is disturbed by the purge air.
Never be done. The electric Namikan 4 tip relative molten
Since the level of the molten metal can be changed arbitrarily, the control value of the molten metal level
Is always best suited to measure that level, even if
Can be set to state.

Therefore, according to the present invention, the use of the ultrasonic sensor 5, which has been considered to be impossible in the past, makes it possible to obtain 1500
It is possible to continuously measure the liquid level of the melt in the furnace, which reaches as high as ℃. Moreover, since the blowing nozzle 8 is provided at a dead position between the waveguide 4 and the ultrasonic sensor 5, there is no risk of affecting the output of the ultrasonic sensor 5.

[0012]

As described above, according to the ultrasonic level meter of the present invention, the method for measuring the level of molten metal by the ultrasonic level meter is used.
Contrary to conventional wisdom , keep it in a furnace with high temperature and high dust.
Accurately measure continuously changing levels over a wide range
It is suitable for a melting furnace for wastes and the like. Therefore, the present invention is a method of measuring the level of molten metal using an ultrasonic level meter that solves the conventional problems, and it greatly contributes to the development of industry.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a main part of the present invention.

FIG. 3 is a graph showing the output fluctuation of the ultrasonic sensor when the position of the blowing nozzle is changed.

[Explanation of symbols]

 1 Furnace wall 4 L-shaped waveguide 5 Ultrasonic sensor 8 Purge air blowing nozzle

Claims (1)

(57) [Claims] 1. An L-shaped waveguide is electrically insulated from one end.
The ultrasonic sensor is connected to the other end of this waveguide.
Is a supercharger inserted in the furnace so that the distance from the molten metal surface can be adjusted.
When measuring the level of molten metal using an acoustic level meter, use a waveguide
Position of the purge air between the ultrasonic sensor and
And measure the output to determine if the output is the most stable dead position.
Measuring the level of the molten metal while injecting purge air from it
Method for Measuring Liquid Level with Ultrasonic Level Meter
Law.