JPH07242431A - Silicon carbide heating element for float bath - Google Patents

Abstract

PURPOSE:To embody high precision of a float bath used for producing plate glass and reduce the energy and space necessary for the float bath. CONSTITUTION:This silicon carbide heating element for a float bath is of single phase type and has edge parts 2 fitted to both ends of the heating part 1 at about 90 deg. angle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicon carbide heating element as a heating source for a float bath used for manufacturing sheet glass.

[0002]

2. Description of the Related Art A float method has been proposed in the production of sheet glass, and most sheet glass is currently formed into a sheet glass by a float bath. A three-phase silicon carbide heating element is used as a heating source used in this float bath. That is, the three-phase silicon carbide heating element as shown in FIG. 3 has three heating portions 1 parallel to the tip portion 5 and an end portion 2 connected to the heating portion 1. As shown in FIG. 4, the three-phase silicon carbide heating element 6 is suspended from the ceiling of the float bath, and the number of the three-phase silicon carbide heating elements 6 to be used is determined by the temperature distribution in the furnace and the temperature rising curve.

[0003]

The above structure has basically not changed since the float bath method was developed. In recent years, energy saving, space saving, and high precision have been required, and new improvements have been made to the float bath itself. In particular, in the conventional method, both the radiation direction of the heater and the glass, which is the object to be heated, have an angle of 90 °, which causes a large loss in thermal efficiency.
Further, since a large volume of the heater is installed, heat loss from the furnace wall is further generated, and the equipment is inevitably large. An object of the present invention is to provide a silicon carbide heating element for providing a float bath that achieves energy saving and space saving, and is able to provide an epoch-making next-generation float bath that has never been seen before.

[0004]

That is, a silicon carbide heating element for a float bath according to the present invention is a single-phase type in a silicon carbide heating element used as a heating source for a float bath in a plate glass manufacturing process. Further, it is characterized in that both ends of the heat generating portion are provided with ends having an angle of about 90 ° with the heat generating portion.

[0005]

The present invention will be described with reference to the drawings. FIG. 1 is a plan view of a silicon carbide heating element for a float bath according to the present invention. That is, the end portions 2 are formed at both ends of the heat generating portion 1 at an angle of approximately 90 °, and are configured in a so-called U-shape. FIG. 2 is a sectional view in which the silicon carbide heating element 3 shown in FIG. 1 is set in a float bath. The heating element and the plate glass, which is the object to be heated, face each other, and the heat of the heater is efficiently radiated in the form of plate glass. FIG. 4 is a cross-sectional view showing a float bath equipped with a conventional three-phase silicon carbide heating element 6, but FIG. 2 has a significantly smaller ceiling volume compared to the float bath of FIG. You can see that it has an energy-saving structure. As described above, according to the present invention, it is possible to provide an unprecedented float bath and save its space.
It can be said that the energy saving effect is very large.

[0006]

EXAMPLES The present invention will be described with reference to examples. Since it is difficult to actually manufacture a float bath using the present invention with large equipment, it was tested in a small experimental furnace. As the furnace internal volume, width 850 mm, depth 850 mm, height 500
4 mm diameter from the ceiling in the experimental furnace of mm size
m, a heating portion length of 750 mm, and an end portion length of 350 mm were attached. The rating of this heater is 140V, 53.5
A was 2.61 Ω, and the glass surface on the hearth became 1000 ° C. in the state of 70 V and 26.8 A. The total applied power of the four wires was 7500W. For comparison, a conventional three-phase heating element having a diameter of 20 mm, a heating portion length of 250 mm, and an end portion length of 350 mm including three legs of a silicon carbide heating element is used.
If the experimental furnace with this set is manufactured and the distance from the heater to the glass surface is almost the same as above, the internal volume of the furnace is 850
× depth 850 × height 700 mm. In this case, in order to bring the glass surface on the hearth to 1000 ° C., the power applied to the four glass rods was 10,000 W. As described above, in this example, the volume was reduced by about 30%, and the electric power was reduced by 25%, showing a great effect.

[0007]

As described above, by adopting the silicon carbide heating element according to the present invention, a completely new float bath which has never existed in the past can be realized. By inserting from the side wall direction, the temperature distribution in the furnace can be improved, and a very large effect can be obtained in terms of accuracy. That is, it can be said that the effect of the present invention is very large in the production of sheet glass for construction and automobiles.

[Brief description of drawings]

FIG. 1 is a plan view of a silicon carbide heating element for a float bath according to the present invention.

FIG. 2 is a sectional view of a float bath using the silicon carbide heating element of the present invention.

FIG. 3 is a plan view of a three-phase type silicon carbide heating element used in a conventional float bath.

FIG. 4 is a sectional view of a float bath using a conventional three-phase silicon carbide heating element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat generating part 2 End part 3 Silicon carbide heating element 4 Glass 5 Tip part 6 Three-phase type silicon carbide heating element

Claims (1)

[Claims] 1. A silicon carbide heating element used as a heating source for a float bath used in the production of sheet glass, comprising:
A silicon carbide heating element for a float bath, which is of a single-phase type and is provided at both ends of the heat generating portion with end portions having an angle of approximately 90 ° with the heat generating portion.