JPH0720290A - Glass melting furnace - Google Patents

Abstract

(57) [Abstract] [Purpose] This relates to a glass melting furnace. By promoting the heating of the vicinity of the surface where the glass raw material is dropped and the low temperature part, the fluctuation of the internal temperature of the melting tank is reduced and the operating efficiency is reduced. Improve. A glass melting furnace for generating a resistance heat by applying an electric current to an object to be heated which is interposed between opposed main electrodes, and is provided above a main electrode and at a position where a liquid surface of the melt is formed. A structure is adopted in which an upper electrode with a narrower facing distance is arranged in the vicinity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass melting furnace,
In particular, it reduces the occurrence of cold tops and improves operating efficiency.

[0002]

2. Description of the Related Art In a glass melting furnace, a material to be heated is charged between electrodes facing each other, and the fact that the material to be heated or the material to be melted has electrical conductivity is utilized. An electric current is passed to generate resistance heat and melt an object to be heated. Examples of the object to be heated include glass used for solidifying high-level radioactive waste (waste liquid).

3 and 4 are shown in Japanese Patent Laid-Open No. 4-161896.
1 shows an example of a conventional structure of a melting furnace disclosed in Japanese Patent Laid-Open No. 4-161897. In each drawing, reference numeral 1 is a melting tank, 2 is a side wall, 3 is an electrode, 4 is a bottom wall, 5 is a bottom electrode, 6 is a ceiling wall, 7 is a raw material supply port, 8 is a discharge port, 9
Is a downflow nozzle, 10 is an inclined inner wall surface, and X is a melt.

In such a melting furnace, an electric current is caused to flow through the molten material X which is a conductor interposed between the pair of electrodes 3 or between the electrode 3 and the bottom electrode 5 to generate a high temperature state by resistance heating. I try to keep it.

[0005]

However, since the glass raw material is intensively dropped in the vicinity of just below the raw material supply port 7, the cold top near the surface of the melt X or the cold top which remains unmelted. Occurs, the current distribution becomes non-uniform, and the operating efficiency of the glass melting furnace may be reduced.

The present invention effectively solves such a problem. That is, the purpose is to promote the heating of the vicinity of the surface where the glass raw material is dropped and the low temperature portion to reduce the variation in the internal temperature of the melting tank and improve the operation efficiency.

[0007]

A glass melting furnace for generating a resistance heat by applying an electric current to an object to be heated which is interposed between opposed main electrodes, the liquid level of the melt being above the main electrode. In the vicinity of the position where is formed, an upper electrode having a narrow upper facing distance is arranged.

[0008]

Function: By passing an electric current between the main electrodes, resistance heating is generated and the object to be heated is melted. When the upper electrode is energized, the current is more likely to flow upward due to the narrowing of the upper facing distance, but if a low temperature portion exists near the surface of the melt, Since the electric resistance of the portion is large and it becomes difficult for the current to flow, the amount of heat generation is averaged, and the cold top is brought into a reduced state.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the glass melting furnace according to the present invention will be described below with reference to FIGS. 1 and 2, reference numeral 11 is a melting tank, 12 is an upper electrode, 13 is a main power feeding means, and 14 is an auxiliary power feeding means.

As shown in FIG. 1, the melting tank 11 has a side wall 2 formed in an inclined shape in which the upper side is narrowed, and the liquid level RL of the melt X is set in this inclined portion.

The upper electrode 12 is, as shown in FIG.
A part of the side wall 2 of the melting tank 11 is exposed so that a part of the side wall 2 protrudes in accordance with the slope of the side wall 2, and the surface is arranged above the main electrode 3 at a spaced position. Then, as shown in FIG. 2, the side walls 2 are arranged at four positions in accordance with the rectangular shape. In the example of FIG. 2, the main electrode (electrode)
3 is also set to be placed in 4 places.

The main power feeding means 13 and the auxiliary power feeding means 14
In this case, the AC power source or the like is connected to the paired main electrode 3 and upper electrode 12, respectively.

In the glass melting furnace configured as described above, the melt X is resistance-heated by energizing the pair of main electrodes 3 from the main power feeding means 13 as in the case of FIGS. 3 and 4. Then, the temperature is maintained below.

In a state in which the upper electrode 12 is not energized by the auxiliary power feeding means 14, the glass raw material is dropped from the raw material supply port 7, so that a low temperature portion or a cold top may occur near the surface of the melt X. However, when the auxiliary power supply means 14 is energized to the upper electrode 12, the upper electrode 12 is inclined and the current distribution in the upper part is increased, and the temperature near the liquid surface RL is low. That is, the current flow becomes less likely to flow, and the current distribution between the paired upper electrodes 12 is ideally uniformed, and heat generation with less unevenness is performed.

Inside the melting tank 1, the temperature in the vicinity of the liquid level RL of the melt X rises, so that when the glass raw material is supplied, it is quickly melted, and the entire inside of the melting tank 1 is brought into a molten state, so that the glass is melted. The operating efficiency of the melting furnace can be improved.

Other Embodiments In the present invention, the following techniques can be adopted instead of the embodiments. a) The numbers of the main electrodes 3 and the upper electrodes 12 are arbitrary. b) When the upper surface of the inner surface of the upper electrode 12 is narrowed, the side wall 2 of the melting tank 11 is a vertical surface. c) The cross-sectional shape of the side wall 2 in the melting tank 1 should be a shape other than a square shape such as a round shape.

[0017]

As described above, the glass melting furnace according to the present invention has the following effects. Above the main electrode and near the position where the liquid surface of the melt is formed,
By adopting a configuration in which the upper electrode with a narrowed upper facing distance is arranged, when the upper electrode is energized, the current can easily flow upward due to the narrowed upper facing distance. The presence of the low temperature part offsets the effect that the electric resistance is large and the current flow becomes difficult, which accelerates the heating of the vicinity of the surface where the glass raw material is dropped and the low temperature part, and reduces the generation of cold top by averaging the calorific value. The driving efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of a glass melting furnace according to the present invention.

FIG. 2 is a plan view showing an embodiment of a glass melting furnace according to the present invention together with a power feeding means.

FIG. 3 is a front sectional view showing a conventional example of a glass melting furnace.

FIG. 4 is a cross-sectional view showing a conventional example of a glass melting furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Melting tank 2 Side wall 3 Main electrode (electrode) 4 Bottom wall 5 Bottom electrode 6 Ceiling wall 7 Raw material supply port 8 Discharge port 9 Downflow nozzle 10 Inclined inner wall surface 11 Melting tank 12 Upper electrode 13 Main power supply means 14 Auxiliary power supply means X Melting RL liquid level

Claims (1)

[Claims] 1. A glass melting furnace for generating a resistance heat by applying an electric current to an object to be heated interposed between opposed main electrodes, wherein a liquid surface of the melt is formed above the main electrodes. A glass melting furnace, in which an upper electrode having a narrower facing distance is arranged near the position.