JPH10281851A - Liquid-level measurement method of glass melting furnace and liquid-level sensor for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for accurately measuring the liquid level of a melted glass in a glass-melting furnace used for hardening a high-level radioactive liquid waste by a glass, and a liquid-level sensor used for the method. SOLUTION: A thermocouple is arranged near the liquid level of at least a melted glass in a melting tank 2 of a glass-melting furnace 1 so that they are arranged in a plurality of rows inside a container, at an equal interval in upper and lower directions, and in a zigzag state, at the same time, a liquid- level sensor 5 with a cooling pipe 8 for introducing a coolant for cooling the internal part of the container is installed in the container, a temperature is detected by a thermoelectric thermometer 18 being connected to the liquid-level sensor 5, and the liquid level of the melted glass is measured by a temperature difference due to the presence or absence of the melted glass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a liquid level in a molten glass of a glass melting furnace used for solidifying a high-level radioactive liquid waste with glass, and a liquid level sensor of the glass melting furnace used in the method. .

[0002]

2. Description of the Related Art In recent years, a vitrification treatment method has been adopted as one of treatment methods for high-level radioactive liquid waste. In this vitrification method, a high-level radioactive liquid waste and a glass raw material are put into a glass melting furnace, melt-mixed, and the melt-mixed glass melt is discharged from a downflow nozzle at the bottom of the furnace and put into a canister (container). Cooling and solidifying. In this vitrification method, it is necessary to accurately measure the liquid level of the molten glass in the glass melting furnace in order to control the amount of the high-level radioactive waste liquid and the glass raw material to be introduced into the glass melting furnace. However, since the vitrification process is performed in an isolated room and the glass melting furnace is sealed, the liquid level cannot be measured while directly observing the liquid level from the outside.

Conventionally, as one method of measuring the liquid level of the molten glass in the glass melting furnace, a measuring rod inserted into the glass melting furnace and inserted until it reaches the liquid level of the molten glass is measured. There is a method to determine the liquid level by detecting the length of the measuring rod.However, this method requires a considerable amount of equipment, and the molten glass adheres to the tip of the measuring rod, thus lengthening the measuring rod. The liquid level could not be measured accurately because Therefore, another melting tank for measuring the liquid level was provided which communicates with the melting tank of the glass melting furnace, and a voltage was applied between the electrodes to measure the liquid level. However, in this method, since it is necessary to provide another melting tank communicating with the melting tank of the glass melting furnace, the structure of the melting tank is complicated, and the structure becomes large-scale. There is a disadvantage that a dedicated power supply for heating the melting tank is required.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a method for accurately measuring the liquid level of a molten glass in a glass melting furnace without providing a separate melting tank, and a liquid level of the glass melting furnace used in the method. It aims to provide sensors.

[0005]

In order to achieve the above object, in the method for measuring the liquid level of a glass melting furnace according to the present invention, a case is provided at least near the liquid level of the molten glass in a melting tank of the glass melting furnace. In multiple rows up and down inside the
And, at equal intervals in the vertical direction, further arrange the thermocouples in a staggered state, and install a liquid level sensor provided with a cooling pipe for introducing a coolant for cooling the inside of the case, The temperature is detected by a thermoelectric thermometer connected to the liquid level sensor, and the liquid level of the molten glass is measured based on the temperature difference depending on the presence or absence of the molten glass.

In order to achieve the above object, in the liquid level sensor for a glass melting furnace according to the present invention, a plurality of rows are provided at the entire height or a part of the inside of the case, and the staggered foot is further provided at equal intervals in the vertical direction. In this state, preferably, at least one surface of a vertically long case made of metal or the like, the upper surface is a horizontal surface (perpendicular to the surface of the case), the surface connected to this surface is a vertical surface, and further connected to this surface A plurality of concave portions (projections when viewed from the inside) whose lower surface is an inclined surface are provided in a plurality of rows in the vertical direction, at equal intervals, and in a staggered state, and the horizontal surface of the concave portion in each case is formed. On the back (opposite side)
That is, a thermocouple is arranged on an upward surface, and a cooling pipe for introducing a coolant for cooling the inside of the case is provided in the case.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a liquid level sensor for a glass melting furnace according to the present invention will be described. The case of the liquid level sensor of the glass melting furnace of the present invention has a vertically long rectangular box shape, a semi-circular cylindrical shape such as a cross section, ceramic,
It is made of a material such as inconel material. The thermocouple placed in this case may be one commonly used to measure the temperature of platinum-platinum rhodium or the like. In addition, the arrangement of the thermocouples placed in the case is such that the thermocouples are arranged in a plurality of rows at equal intervals in the vertical direction over the entire height of the case or partially (as shown in FIG. 1) and in a staggered state (see FIG. 1). 1). The range that can be measured further (the range where the thermocouple is installed)
It is preferable that the length is longer, but the length may be about three times the amount of one discharge (filling into one canister). The plurality of rows are arranged in a staggered state because the arrangement intervals of the thermocouples can be reduced, and as a result, measurement can be performed with high accuracy. The liquids are arranged at equal intervals because the liquid level of the molten glass is measured based on the temperature difference depending on the presence or absence of the molten glass.

In the case where the thermocouple is installed in the case, at least one surface of the case is provided with a concave portion (a convex portion as viewed from the inside), in particular, an upper surface is a horizontal surface, and a surface connected thereto is a vertical surface. Further, it is preferable to provide a concave portion having a lower surface continuous with the inclined surface and to install the concave portion on the surface (upper surface of the convex portion) opposite to the horizontal surface of the concave portion (see FIG. 4), so that the heat transfer area is large and The inclined surface is preferable because the accumulation of the molten glass can be prevented, but it is preferable that a shelf is provided inside one surface of the case and the shelf is provided thereon.
If the case 6 is made of ceramics as shown in FIG. 1, a hole 19 may be provided inside one surface, and the hole 19 may be provided therein.

The cooling pipe for introducing a coolant for cooling the inside of the case has a circular or square cross section, and is arranged so that its lower end is slightly above the bottom of the case. Preferably, the coolant is arranged so as to rise from below. And the coolant introduced by the cooling pipe is water,
Air or the like may be used, but if the case is made of ceramic, it may be air at room temperature, and if it is made of Inconel, water is preferred. In addition, when a thermometer is connected to this liquid level sensor, the thermometer is normally used and can simultaneously display the temperature of all places where thermocouples are installed. What can be done is preferred.

Next, a method for measuring the liquid level in the glass melting furnace will be described. In the method for measuring the liquid level of the glass melting furnace of the present invention, at least in the vicinity of the liquid level of the molten glass in the melting tank of the glass melting furnace, a plurality of rows inside the case, and at equal intervals, further staggered state. A liquid level sensor provided with a cooling pipe for introducing a coolant for cooling the inside of the case, and a thermoelectric temperature connected to the liquid level sensor. It is to measure the liquid level of the molten glass by the temperature difference by the presence or absence of the molten glass by detecting the temperature with a meter, a glass melting furnace to which the present invention can be applied,
Any application and type of glass melting furnace may be used, such as a glass melting furnace used to solidify high level radioactive liquid waste with glass.

[0011] The liquid level sensor is installed in a place where the back surface is not in contact with the two electrodes of the melting tank and the back surface is in contact with the wall of the melting tank or is partially buried in the wall of the melting tank. Is preferred. The length and installation height of the liquid level sensor may be set to a length that can be measured from the bottom to the ceiling of the melting tank, or about three times the discharge amount of a glass melting furnace at one time. May be installed such that the center of the group of thermocouples has a height at which the liquid level of the standard molten glass is attained. In addition, the thermoelectric thermometer connected to this liquid level sensor is the one normally used for the above-described thermoelectric thermometer, and can simultaneously display the temperatures of all places where the thermocouples are installed. Are preferred. (See FIG. 5) The method of obtaining the liquid level from the result measured by the thermoelectric thermometer is as described in the following examples.

[0012]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front view of a liquid level sensor of a glass melting furnace according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, and FIG. FIG. 4 and FIG.
FIG. 3 is an enlarged view of a portion C in FIG. 2. As shown in FIGS. 1 and 2, a liquid level sensor of a glass melting furnace according to an embodiment of the present invention includes a case 6 and eight thermocouples 7a to 7h (7b, 7b, 7d and 7f are not shown.)
It is composed of a cooling pipe 8 for introducing water as a coolant for cooling the inside of the case, a discharge pipe 9 for discharging water, and a cable 10 in which lead wires connected to a thermocouple are collected. The case 6 is a long and narrow box-like material made of Inconel material, and is arranged at equal intervals in the vicinity of the liquid level of the molten glass on the front side 11, that is, four in two rows so as to be above and below the liquid level.
Further, concave portions 12a to 12h are provided so as to be in a staggered state. These concave portions 12a to 12h are convex portions when viewed from the inside of the case as shown in FIGS.
An upper horizontal plane 13, that is, a plane perpendicular to the surface of the case, a vertical plane 14 continuing below this plane, an inclined plane 15 continuing to this vertical plane 14, and left and right vertical planes 16a, 16b It is.

Thermocouples 7a to 7h are fixed to a surface 17 on the opposite side (back side) of the horizontal plane 13 above the concave portions 12a to 12h of the case 6, that is, upper surfaces of the convex portions. A conductor is connected to each of the thermocouples 7a to 7h, and a cable 10 combining the conductors is connected to a thermoelectric thermometer 18 installed in a separate room from the case 6.
(See FIG. 5). A circular cooling pipe 8 for introducing water for cooling the inside of the case 6 is installed so that the lower end thereof is slightly above the bottom of the case 6. A discharge pipe 9 is fixed to the ceiling of the case 6, cooling water is introduced into the bottom of the case 6 through the cooling pipe 8, rises while being heated, and the heated water is discharged from the discharge pipe 9. ing.

Next, a method of using and a function of the liquid level sensor will be described. FIG. 5 is a sectional view of a glass melting furnace provided with a liquid level sensor for a glass melting furnace according to the present invention, and FIG. 6 is a plan view of what is shown in FIG. The liquid level sensor 5 is provided with a concave portion of the liquid level sensor 5 at a position where the liquid level of the standard molten glass in the melting tank 2 of the glass melting furnace 1 becomes a level as shown in FIGS. 12
A cable 10 is connected to a thermoelectric thermometer 18 installed in a separate room, so that there is a central part between a and 12h and not between the two electrodes 3a and 3b. When the glass melting furnace 1 is operated while putting water into the cooling pipe 8 and cooling it, the liquid level sensor 5 installed in this manner is turned on by each of the thermocouples 7a to 7h according to each liquid level. The temperature is detected and displayed by the thermoelectric thermometer 18, and the liquid level is obtained from the temperature distribution displayed on the thermoelectric thermometer 18. Reference numeral 4 is a nozzle for discharging molten glass.

A method of obtaining the liquid level from the temperature measured by the thermoelectric thermometer 18 will be described. The temperature distribution near the liquid level is as shown in FIG. This temperature is divided into three types of L (low temperature), M (medium temperature) and H (high temperature) as shown in FIG. 7, and the temperature obtained from each thermocouple is displayed for each liquid level. The result is as shown in the section. In addition, the left side of FIG. 8 shows the concave portion of the liquid level sensor 5 and the installation location of the thermocouple.

A method of obtaining the liquid level from the displayed data will be described with reference to an example of six columns in FIG.
The thermocouples 7h to 7f indicate low temperature L, that is, no molten glass, and the thermocouples 7e to 7a indicate high temperature H, that is, there is molten glass. This is the level of the thermocouple 7e described, which is shown in FIG.
D level. Similarly, taking the five rows in FIG. 8 as an example, thermocouples 7h to 7f indicate low temperature L, thermocouple 7e indicates medium temperature M, that is, molten glass is close, and thermocouples 7d to 7a indicate The liquid level is at a level between the thermocouples 7e and 7d because it shows a high temperature of H, which is the level of E in FIG. Further, taking the four columns in FIG. 8 as an example, the thermocouples 7h to 7e indicate a low temperature L, and the thermocouples 7d to 7a indicate a high temperature H. This is the level of F in FIG. In this way,
The liquid level can be measured based on the detection result of the liquid level sensor 5.

In practice, if it is known that such a result is obtained, if the temperature measured by each thermocouple is continuously displayed on the thermoelectric thermometer 18 as shown in FIG. It will be understood in the same way as displaying the plane level. For example, from the display of the thermoelectric thermometer 18 in FIG. 5, the liquid level of the molten glass rises from the level of 7c to the level of 7d, and from here, 7c
You can see that it is falling to the level between 7d.

In the above-described embodiment, eight thermocouples are used as the liquid level sensor. However, the number of thermocouples can be increased or decreased as needed. Also, in the above embodiment, a thermoelectric thermometer was connected to the liquid level sensor, but a computer was connected to the liquid level sensor, and the one detected by the liquid level sensor was processed by the computer and the liquid level was measured. Levels can be displayed directly. Note that the present invention is not limited to only the above-described ones, and it is needless to say that various changes can be made without departing from the gist of the present invention.

[0019]

According to the present invention, the above-described configuration enables
It has the following excellent effects. (1) Since there is no need to provide another melting tank used for measuring the liquid level, the configuration of the furnace is simplified. (2) Since the liquid level sensor has a plurality of thermocouples arranged at equal intervals in the vertical direction and in a staggered manner, it can measure with high accuracy. (3) Since the inside of the liquid level sensor is cooled, measurement accuracy can be increased,
The life of the liquid level sensor can be extended. (4) In the case where a concave portion is provided in the container and a thermocouple is provided on the opposite side of the upper surface of the concave portion, since the heat transfer area is large, the measurement accuracy can be increased, and In the case where the lower surface is an inclined surface, the molten glass does not accumulate, so that the measurement accuracy can be further increased.

[Brief description of the drawings]

FIG. 1 is a front view of a temperature sensor for measuring a liquid level in a glass melting furnace according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is an enlarged view of a portion B in FIG. 1;

FIG. 4 is an enlarged view of a portion C in FIG. 2;

FIG. 5 is a sectional view of a glass melting furnace provided with a liquid level sensor according to one embodiment of the present invention.

FIG. 6 is a plan view of what is shown in FIG.

FIG. 7 is an explanatory diagram for explaining a liquid level measurement method when the liquid level sensor of the present invention is used.

FIG. 8 is an explanatory diagram for explaining a method for measuring a liquid level when the liquid level sensor of the present invention is used.

FIG. 9 is an explanatory diagram for explaining a method and a function of measuring a liquid level when the liquid level sensor of the present invention is used.

FIG. 10 is a sectional view of a part of a liquid level sensor for a glass melting furnace according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass melting furnace 2 Glass melting furnace melting tank 3a, 3b electrode 4 Discharge nozzle 5 Liquid level sensor 6 Case 7a-7h Thermocouple 8 Cooling pipe 9 Discharge pipe 10 Cable 11 Front side of case 12a-12h Concave 13 Horizontal plane of concavity 14 Vertical surface of recess 15 Slope of recess 16a, 16b Vertical surface of right and left of recess 17 Surface opposite to horizontal surface 18 Thermoelectric thermometer 19 Hole provided in case

Claims (4)

[Claims] 1. A plurality of rows inside a case at least near a liquid level of molten glass in a melting tank of a glass melting furnace,
And at equal intervals, further arrange a thermocouple so as to be in a staggered state, and install a liquid level sensor provided with a cooling pipe for introducing a coolant for cooling the inside of the case, A liquid level measuring method for a glass melting furnace, comprising detecting a temperature with a thermoelectric thermometer connected to the liquid level sensor and measuring a liquid level of the molten glass based on a temperature difference depending on the presence or absence of the molten glass. 2. A thermocouple is arranged in a plurality of rows at equal intervals inside the case so as to be in a staggered state, and a coolant for cooling the inside of the case is introduced into the case. A liquid level sensor for a glass melting furnace provided with a cooling pipe. 3. The installation place of the thermocouple inside the case is provided with a plurality of recesses on at least one surface of the case at equal intervals and further in a staggered state, and inside the case, 3. The liquid level sensor for a glass melting furnace according to claim 2, wherein the liquid level sensor is located on the back side of the upper surface. 4. The glass according to claim 3, wherein the upper surface of the concave portion of the case is a horizontal surface, the surface connected thereto is a vertical surface, and the lower surface connected thereto is an inclined surface. Liquid level sensor for melting furnace.