JPH055826U - Lead glass melting furnace - Google Patents

Abstract

(57) [Summary] [Objective] In a lead glass melting furnace, the reaction between molybdenum used as an electrode and lead glass is suppressed to improve glass quality. [Configuration] In a glass melting furnace having an upper heating source,
At the bottom of the furnace, a low hearth part which is not easily affected by the heat from the upper heating source was provided, and a molybdenum electrode was placed there. Therefore, the electrode comes into contact with the glass in a relatively low temperature range, and the reaction between molybdenum and lead is suppressed.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to auxiliary electric melting by an electrode inserted in a molten glass, and more particularly, to a lead glass melting furnace that supplies heating power auxiliary by a molybdenum electrode arranged in the glass melting furnace.

[0002]

[Prior Art]

 Conventionally, by heating the glass and inserting electrodes into it to apply AC power, an electric current is passed through the glass between the electrodes to generate Joule heat inside the glass. A method of melting glass is widely used.

In this glass melting method, molybdenum electrodes are generally used as electrodes. Molybdenum has excellent high-temperature strength and does not adversely affect glass, so it is suitable as an electrode material.

[0004]

[Problems to be solved by the device]

 However, in lead glass, molybdenum has the drawback that it reacts with lead at a high temperature and is significantly eroded, and lead oxide in the glass is also reduced to lead to metallic lead and deposits at the bottom of the melting furnace. ..

Further, the tin oxide electrode used in the lead glass furnace is neutral to the glass and does not need to be water-cooled, and is used for melting the lead glass. Therefore, the initial equipment cost increases, and the current load density on the electrode surface is severely limited compared to molybdenum electrodes.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a lead glass melting furnace in which the temperature of the lead glass near the molybdenum electrode is lowered and the reaction between molybdenum and lead glass is suppressed.

[0007]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention is a lead glass melting furnace that heats and melts a glass raw material continuously or intermittently charged by a heating source arranged in the upper part, and it is lower than the surrounding hearth. It is characterized by comprising the formed low-hearth part and a molybdenum electrode which is vertically disposed in the low-hearth part and which supplementarily supplies electric power for heating the molten glass.

[0008]

[Action]

 Since the present invention is configured as described above, the temperature of the lead glass near the molybdenum electrode becomes lower in the low-hearth part where the molybdenum electrode is arranged, and the temperature of the lead glass near the molybdenum electrode becomes lower. The reaction of lead glass is suppressed.

[0009]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional explanatory view of a lead glass melting furnace according to an embodiment of the present invention as seen from a side surface, and FIG. 2 is a cross-sectional explanatory view showing an electrode arrangement and a power system for the electrodes as seen from the plane of FIG. ..

In the above figure, reference numeral 1 is a melting furnace made of refractory bricks, which is formed by a peripheral wall 2 and a hearth 3, and one of the peripheral walls 2 of the melting furnace 1 is provided with a glass raw material 4 containing a lead component. The inlet 5 and the other peripheral wall 2 are respectively provided with a discharge port 7 for discharging the molten glass 6 melted in the melting furnace 1. A heating source (not shown) such as a heavy oil burner is installed in the upper part of the melting furnace 1, and the glass raw material 4 continuously or intermittently injected from the charging port 5 is melted by the heating source. Molten glass containing lead component is converted to PEG.

Further, near the center of the hearth 3, there is formed a low hearth part 3a whose floor surface is lower than that of the surrounding hearth 3, and in this low hearth part 3a, the flow of the molten glass 6 is formed. The molybdenum electrodes 8 and 8 for auxiliary heating of the molten glass 6 by passing an electric current in a direction perpendicular to the same have the same surface as the floor of the surrounding hearth 3 and are perpendicular to the floor, and the peripheral walls facing each other. It is located on the 2 side. The required power is supplied from the single-phase AC transformer 9 to the molybdenum electrodes 8 and 8.

Next, the operation of the embodiment of the present invention having the above structure will be described.

The glass raw material 4 continuously or intermittently charged from the charging port 5 of the melting furnace 1 is melted by a heating source (not shown) arranged in the upper part of the melting furnace 1, and the molten glass is sequentially melted. Convert to 6. A maximum temperature region is formed near the center of the hearth 3 where the low hearth portion 3a is formed, and the molten glass 6 in the maximum temperature region of relatively high temperature and low density forms an upward flow. When power is supplied to the molybdenum electrodes 8 and 8 arranged in this maximum temperature region through the single-phase AC converter 9, a current flows through the molten glass 6 and Joule heat is generated inside the molten glass 6. The heating action by the generation of this Joule heat heats the molten glass 6, and the upward flow of the molten glass 6 is strongly promoted as shown by the arrow.

The above-mentioned upward flow restrains the advance of the unmelted glass raw material 4 floating on the surface of the molten glass 6 along the upstream, and stirs the molten glass 6 to improve the clarity / homogeneity of the molten glass 6. To improve. The clarified and homogenized molten glass 6 is discharged from a discharge port 7 and is usually supplied from a distributor to a glass forming device (not shown) via a feeder.

By the way, the low hearth part 3a is formed lower than the floor surface of the surrounding hearth 3, and the molybdenum electrodes 8 arranged in the low hearth part 3a are the floor surfaces of the surrounding hearth 3. Since the molybdenum electrodes 8 and 8 are located on the side of the peripheral wall 2 facing each other with the upper surface being flush with or lower than that, the position where the molybdenum electrodes 8 and 8 are disposed is the heat generated from the heating source. It is the position that is least affected by. Therefore, the molten glass 6 in the vicinity of the molybdenum electrodes 8 and 8 is also least affected by the heat generated from the heating source, so that the temperature rise of the molybdenum electrodes 8 and 8 due to the heating source is suppressed. In the reaction between lead glass and molybdenum, generally, the higher the melting temperature, the greater the loss of molybdenum, and it tends to accelerate exponentially from a certain temperature. By suppressing, the reaction rate with the lead component in the molten glass 6 is reduced, and the life of the molybdenum electrodes 8 and 8 due to molybdenum wear and the glass contamination are prevented.

The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0018]

[Effect of the device]

 As described above in detail, according to the lead glass melting furnace of the present invention, by placing the molybdenum electrode in the lower hearth portion formed lower than the surrounding hearth, the heat generated from the heating source is Since it is not affected, the reaction between molybdenum and lead can be suppressed, and the life of the molybdenum electrode due to wear of molybdenum and the glass contamination can be prevented.

Further, by supplying electric power to the molybdenum electrode, the molten glass is energized and the convection of the molten glass is activated in the vicinity of the central part of the melting furnace, so that the melting, refining and homogenization of the glass is smooth. It is possible to produce excellent quality glass.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a lead glass melting furnace according to an embodiment of the present invention as viewed from the side.

FIG. 2 is a cross-sectional view showing an electrode arrangement and a power system for the electrodes when viewed from the top of a lead glass melting furnace according to an embodiment of the present invention.

[Explanation of symbols]

 1… Melting furnace (lead glass melting furnace) 3… Hearth 3a… Low hearth 4… Glass raw material 5… Rough cut device 6… Molten glass 8… Molybdenum electrode

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 26, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief explanation of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a lead glass melting furnace according to an embodiment of the present invention as viewed from the side.

FIG. 2 is a cross-sectional view showing an electrode arrangement and a power system for the electrodes when viewed from the top of a lead glass melting furnace according to an embodiment of the present invention.

[Explanation of symbols] 1 ... Melting furnace (lead glass melting furnace) 3 ... Hearth 3a ... Low hearth 4 ... Glass raw material 5 ... Input port 6 ... Molten glass 8 ... Molybdenum electrode

Claims (1)

[Claims for utility model registration] [Claim 1] In a lead glass melting furnace in which a glass material continuously or intermittently charged is heated and melted by a heating source arranged at the upper part, it is formed lower than the surrounding hearth A lead glass melting furnace characterized by comprising: a low furnace hearth section and a molybdenum electrode which is arranged vertically to the low hearth section and supplies electric power for heating the molten glass.