JPH0735254B2 - Glass electric melting furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a glass melting furnace for melting glass by Joule heat generated by directly energizing the glass itself, and particularly, a small electric resistance during melting. It relates to a glass electric melting furnace suitable for melting glass.

(Prior Art) Conventionally, a glass electric melting furnace is one in which the glass itself is directly energized via an electrode arranged in a melting tank to melt the glass. Since an attempt is made to flow in a portion (hereinafter referred to as resistance) having a small value, a high-density current flows in the straight current-carrying path which is the shortest distance between the electrodes. Although glass is an electrical insulator at room temperature, its resistance gradually decreases with increasing temperature. The specific resistance of this glass greatly differs depending on the composition of the glass, but when a glass having a small specific resistance, such as a glass having a large content of alkali oxides, is electrically fused, there are the following problems.

Since the specific resistance of the glass between the electrodes is small, a large current flows when the glass is melted even if the voltage applied to the electrodes is low. In order to introduce the electric power required to promote the melting of the glass, the higher the applied voltage is, the larger the current is, and the higher the current density of the electrode is. When the current density of the electrode increases,
The temperature of the electrode surface rises and the consumption of the electrode rapidly progresses. If the surface area of the electrodes is increased in order to reduce the current density of the electrodes, the resistance between the electrodes is reduced and the current flows more easily, and the problem cannot be solved. In addition, when a constant amount of power is supplied from the aspect of power supply equipment, low-voltage / high-current type equipment is larger than high-voltage / low-current type equipment.

In order to increase the resistance between the electrodes, if the electrodes are spaced apart from each other to form an elongated furnace, the surface area of the furnace wall increases with respect to the volume of the melting tank, the amount of heat released increases, and the heat exchange rate decreases significantly. To do.

Due to the above problems, it is difficult to electrically melt glass having a low specific resistance.

(Problems to be Solved by the Invention) The present invention has been made in consideration of the above circumstances, and by substantially increasing the resistance of glass between electrodes arranged in a glass melting tank, the specific resistance is increased. It is an object of the present invention to provide a glass electric melting furnace capable of efficiently melting glass having a small size.

[Structure of Invention]

(Means and Actions for Solving Problems) In order to achieve the above object, the present invention cuts off a linear current-carrying path between electrodes and provides another current-carrying path extended from this current-carrying path. It is a thing. For example, it is a glass electric melting furnace provided with a barrier that interrupts a straight current path between electrodes and has a barrier having an opening corresponding to another current path extended from this current path.

(Operation) In the glass electric melting furnace of the present invention, the shortest distance between the electrodes, that is, the straight current path is interrupted by, for example, a barrier, and passes through a current path extended from this current path, for example, an opening of the barrier. Since a current flows along the current-carrying path and the resistance of the glass between the electrodes is substantially increased, the required electric power can be efficiently introduced and melted even for the glass having a small specific resistance.

(Examples) The details of the present invention will be described with reference to illustrated examples.

In FIGS. 1 to 3, electrodes (2) made of metal molybdenum are arranged along both sides of the glass melting tank (1) along the furnace wall, and electrodes (2) are provided almost at the center of the melting tank (1). 2) is provided in parallel with a barrier (3) made of a ceramic refractory. The barrier (3) extends downward from the vicinity of the glass level of the molten glass (4) across the inside of the tank, and the lower end thereof forms an opening (5) serving as an electric path with the bottom of the tank. One end of the electrode (2) is connected to a power supply device (not shown) outside the furnace. The melting tank (1) communicates with the refining tank (7) via the throat (6).

In the glass electric melting furnace configured as described above, the fourth
As shown in the figure, when the furnace is operated in a state in which the glass level in the melting tank (1) does not exceed the upper end of the barrier (3), between the electrodes (2) to which a predetermined voltage is applied by the power supply device. Current flows through the molten glass (4) along the current path (8) passing through the opening (5) below the barrier (3). This current-carrying path (8) is about 1.3 times the linear distance between the electrodes (2) or more, and the resistance between the electrodes (2) increases. Therefore, even if the glass has a small specific resistance, the resistance is substantially increased. Thus, the appropriate resistance required for glass melting is obtained.

As shown in FIG. 5, the glass raw material (9) is placed in the melting tank (1).
Was charged, and the glass level was raised by the glass raw material (9), and when the furnace was operated in a state in which the semi-molten glass (4) 'exceeded the upper end of the barrier (3), it exceeded the barrier (3). A current path (8) 'is also formed in the semi-molten glass (4)', and an electric current flows. Semi-molten glass (4) 'in this energizing path (8)'
Has a lower temperature than the lower molten glass (4) and contains a large amount of semi-molten bubbles and has a large resistance, so that the current between the electrodes (2) is at the upper short-distance side current path (8). ) ′ Is not concentrated, but by adjusting the glass level of the molten glass (4), a part of the introduced electric power can be used for the heat generation of the upper part, and the melting of the glass raw material (9) is promoted. Has the effect of

Next, FIG. 6 and FIG. 7 show another embodiment of the present invention, in which the electrode (2) is arranged along one side wall of the melting tank (1) along the furnace wall. A barrier (3) is provided at approximately the center of the electrode so as to divide the electrode (2). This barrier (3) reaches from the vicinity of the glass level of the molten glass (4) to the bottom of the tank, and one end of the barrier (3) forms an opening (5) serving as an electric conduction path with the furnace wall. In this glass electric melting furnace, the current between the electrodes (2) flows through the opening (5) on the side of the barrier (3), so that the same effect as in the above embodiment can be obtained.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the present invention is a glass electric melting furnace which interrupts a linear current-carrying path between electrodes arranged in a glass-melting tank and is provided with another current-carrying path extended from this current-carrying path. ,
Since the resistance of the glass between the electrodes increases due to the extension of the current-carrying path, the introduced power can be supplied at high voltage and low current,
There is an advantage that a glass having a small specific resistance such as a glass having a high content rate of an alcal oxide can be efficiently melted.

[Brief description of drawings]

1 is a plan view showing an embodiment of the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, FIG. 3 is a sectional view taken along line BB of FIG. 1, and FIG.
FIG. 5 is a sectional view showing an energized state during melting of glass, FIG. 5 is a sectional view showing an energized state during charging of glass raw materials, FIG. 6 is a plan view showing another embodiment of the present invention, and FIG. 6 C-C
FIG. 1 ... Melting tank, 2 ... Electrode, 3 ... Barrier, 5 ... Opening, 8 ... Current path

Claims (2)

[Claims] 1. A glass electric melting furnace in which glass is melted by Joule heat generated by directly energizing the glass itself through an electrode arranged in a glass melting tank, and a linear current path between the electrodes is cut off. However, the glass electric melting furnace is characterized in that another electric current path extended from this electric current path is provided. 2. A barrier for blocking a linear current path between the electrodes and having a barrier having an opening corresponding to another current path extended from the current path. The electric glass melting furnace according to item 1.