JPS59121125A - Production unit of floating plate glass - Google Patents

Abstract

PURPOSE:A production unit of floating plate glass for lessening strain of molten glass ribbon made to flow on a metallic bath, suppressing variability in thickness, by making a fence along the side wall of the molten metallic bath, using it as a return path for the molten metal. CONSTITUTION:The molten metal bath 10 is filled with the molten metal 11 such as tin, etc., and a molten glass material is made to flow on the molten metal 11. As it is drawn by rollers, it is pulled up, the beltlike glass ribbon 12 is transferred on the molten metal 11, to give plate glass having given thickness and width. In this device, the fence 13 is set along the side wall 10a in the bath 10, to form the return path 16 for the molten metal 11. The cooled molten metal 11 is made to flow downward with the transfer of the glass ribbon 12, and allowed to flow along the return path 16 into the main flow 11a. If necessary, the return path 16 is equipped with a heater to heat the cooled molten metal 11. Consequently, the cooled molten metal 11 is not brought into contact with the glass ribbon 12 to give high-quality plate glass.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a float-type sheet glass manufacturing apparatus for manufacturing sheet glass of a constant thickness by pouring molten glass onto a molten metal such as tin. A type of plate glass manufacturing equipment is used. As shown in FIG. 1, this manufacturing apparatus consists of a bath 2 filled with molten metal 1 such as tin.
A molten glass base material is poured onto the bath 2 to form a glass ribbon 3, and a heater or cooler installed in the middle of the bath 2 controls the temperature of the glass ribbon 3 to a temperature suitable for molding. By pulling the glass ribbon 3 from the downstream end of the bath 2 at a predetermined speed while pulling it laterally using a roll or the like, a plate glass having an appropriate thickness and width is obtained.

In such a float-type manufacturing apparatus, the glass ribbon 3 moves over the molten metal 1, and as the glass ribbon 3 moves, the molten metal 1 also moves from upstream to downstream. Since the downstream end of the bath 2 is dammed, the molten metal 1 that has reached the downstream end of the bath 2 is deposited between the glass ribbon 3 and the side wall 2a of the bath, or between the glass ribbon 3 and the side wall 2a of the glass ribbon 3, as shown in FIG. Pass below and return upstream.

However, the molten metal that has moved to the downstream end of the bath 2 has been cooled considerably, and when this cooled molten metal comes into contact with the hot glass ribbon 3 on its way back upstream, the glass ribbon 3 is distorted and its elongation quality is poor. Become. In particular, this negative effect is often caused by the cold molten metal passing between the glass ribbon 3 and the side wall 2a of the bath.

The present invention has been made to improve the above-mentioned conventional problem.As the glass ribbon moves, the molten metal moves to the downstream end of the bath and becomes cold. It is an object of the present invention to provide a float-type sheet glass manufacturing apparatus that can prevent contact and thereby manufacture sheet glass with little distortion and good elongation quality.

In order to achieve the above object, the first invention provides a barrier along the side wall of the metal bath inside the metal bath in a float-type plate glass manufacturing apparatus, and opens the upstream and downstream ends of the barrier to connect the barrier and the side wall. The gist of the invention is that a reflux path for molten metal is formed between the molten metal, the gist of the second invention is that a heater is disposed in the reflux path of the first invention, and the third invention is a reflux path of the molten metal formed upstream of the first invention. The gist is that a weir is installed slightly upstream of the opening at the end, allowing the cooled molten metal returning from the reflux path to flow into the main stream at a predetermined position.

Embodiments of each invention will be described below based on the accompanying drawings.

2 and 3 show an embodiment of the first invention, FIG. 2 is a plan view of a sheet glass manufacturing apparatus, and FIG. 3 is a vertical sectional view of the main part of the apparatus. This bath 10 has a substantially rectangular shape with 1,000 sides, and both side walls 1 are formed in the downstream part.
0a, 10a width is narrower and bath 1
The bath 10 is filled with molten metal 11 such as tin, and a molten glass base is poured onto this molten metal 11, and this glass base is pulled up while being pulled by a roller disposed near the downstream end of the bath 10. This causes the band-shaped glass ribbon 12 to move on the molten metal 11 to the right in the figure.

In this case, the temperature of the glass ribbon 12 is controlled by providing a heater or cooler in the middle of the bath 10, and the width of the glass ribbon 12 is prevented from shrinking by the top roll, and a plate glass having a predetermined thickness and width is used. I'm trying to get it.

The interior of the mushroom bath 10 forms barriers 13.13 along the side walls 10a, 10a. The lower end of this barrier 13 is fixed to the flooring surface of the bath 10, and its material is carbon or a refractory material similar to the flooring bricks of the bath 10. and,
Molten metal 1 in bath 10 is located at the upstream and downstream ends of barrier 13.
Openings 14 and 15 are formed that communicate with the main stream 11a of No. 1. Thus, a reflux path 16 for molten metal is formed between the barrier 13 and the side wall 10a. Here, the downstream end of the barrier 13 and the rear end wall 10b of the bath 10 are
If the distance is too close to the barrier, the effectiveness of tin oxide removal will be reduced, and if it is too far apart, there is a risk that the cooled molten metal may flow back inside the barrier. preferable.

Further, the width A of the return flow path 16 at the upstream portion of the barrier 13 is larger than the distance B between the barrier 13 and the side edge of the glass ribbon 12, and the width C of the return flow path 16 at the downstream portion of the barrier 13 is also larger than the distance B between the barrier 13 and the side edge of the glass ribbon 12. The distance from the side edge of the ribbon 12 is also large, that is, the relationship A≧B1C≧D exists.
This is preferable in that it prevents reflux inside the barrier 13.

Further, the upstream end position of the barrier 13 is the main flow 11a of the molten metal.
It is preferable that the temperature be 700° C. to 750° C. By doing so, even if the cooled molten metal flows into the main flow 11a, there is no major influence.

Furthermore, in the illustrated example, the upper end of the barrier 13 is the molten metal surface S.
Although it is preferable to have a protruding barrier, the upper end of the barrier may be below the molten metal surface. In this case, if the barrier 13 is sunk too far from the molten metal surface S, the barrier effect will be lost, so the distance between the molten metal surface S and the top of the barrier 13 is 1/3 or less of the depth H of the molten metal 11 or 20 m or less. It is preferable to select the smaller one among them.

With the above configuration, the molten metal that has flowed down and been cooled as the glass ribbon 12 moves passes through the reflux path 16 to a predetermined temperature, and even if the molten metal that has cooled down joins it, it will not be affected much. It flows into the main stream 11a where there is no water.

4 and 5 show an embodiment of the second invention, FIG. 4 being a plan view similar to FIG. 2, and FIG. 5 being a longitudinal sectional view of the main part.

This embodiment differs from the previous embodiments in that a heater 17 is disposed within the reflux path 16. This heater 17 is the fifth
As shown in the figure, a hollow sealed carbon box 18 is attached to the inside of the side wall 10a of the bath 10, and a heater wire 19 connected to a power source is housed within this carbon box 18.

Note that the heater 17 is not limited to this, and a heater that heats the metal bath from the upper surface may be used.

With this configuration, there is no need to consider the position of the upstream end of the barrier 13, the opening 14 can be set at any position, and the molten metal is cooled to a temperature equal to the temperature of the main stream 11a. Since the molten metal can be heated and merged, there is no need to worry about distortion of the glass ribbon 12.

Still, FIG. 6 shows an embodiment of the third invention, and in this embodiment, the upstream end of the barrier 13 is also covered with carbon or refractory material from the side wall 10a slightly upstream. A weir 20 made of

When the weir 20 is provided in this manner, the cooled molten metal flowing out from the opening 14 of the return flow path 16 is blocked by the weir 20 and does not flow upstream, but instead joins the main stream 11a. Therefore, if the weir 20 is installed at a location where the temperature of the main stream is, for example, 700°C, the temperature of the main stream 11a of the molten metal 11 and the temperature of the cold molten metal can be returned before the difference in temperature becomes large. Adverse effects caused by temperature differences, that is, distortion of the glass ribbon, can be minimized as much as possible.

As explained above, according to the first invention, a barrier is formed along the side wall of the molten metal bath, and the space between the barrier and the side wall is used as a reflux path, so that the cooled molten metal can flow toward the upstream side without contacting the glass ribbon. This has many advantages, such as reducing distortion of the glass ribbon, suppressing thickness fluctuations, and greatly improving elongation quality.

[Brief explanation of drawings]

The drawings show a conventional example and an embodiment of the present invention, and FIG. 1 is a plan view of a conventional float type plate glass manufacturing apparatus, and FIG. 2 is a plan view of a float type plate glass manufacturing apparatus according to the first invention. 3 is a longitudinal cross-sectional view of a main part of the same manufacturing apparatus, FIG. 4 is a plan view of a float type sheet glass manufacturing apparatus according to the second invention, FIG. 5 is a longitudinal cross-sectional view of a main part of the apparatus according to the second invention, and FIG. The figure is a plan view of a float type plate glass manufacturing apparatus according to the third invention. 14.15 is an opening, 16 is a reflux path, 17 is a heater, 2
0 is a weir. Patent applicant Nippon Sheet Glass Co., Ltd.

Claims (1)

[Claims] In a float-type manufacturing apparatus in which a plate glass of a predetermined thickness is obtained by drawing out glass into a ribbon shape and pulling up the ribbon-shaped glass under tension, A float-type plate glass characterized in that a barrier is provided along the line, and the upstream and downstream ends of the barrier are opened to the main stream of molten metal to form a return path for molten metal between the barrier and the side wall. Manufacturing equipment. (2) In a float-type manufacturing apparatus, the molten glass is poured onto a metal bath filled with molten metal to form a ribbon, and the ribbon-shaped glass is pulled up under tension to obtain a plate glass of a predetermined thickness. A barrier is provided inside the metal bath along the side wall of the metal bath, and the upstream and downstream ends of this barrier are opened to the main flow of the molten metal to form a return path for the molten metal between the barrier and the side wall. 1. A float type sheet glass manufacturing apparatus characterized in that a heater is provided in the reflux path. (3) In a float-type manufacturing apparatus, the molten glass is poured onto a metal bath filled with molten metal to form a ribbon, and the ribbon-shaped glass is pulled up under tension to obtain a plate glass of a predetermined thickness. A barrier is provided inside the metal bath along the side wall of the metal bath, and the upstream and downstream ends of this barrier are opened to the main flow of the molten metal to form a reflux path for the molten metal between the barrier and the side wall. A float type plate glass manufacturing apparatus further comprising: a weir for allowing the molten metal returned from the reflux path to flow into the main flow upstream of the opening provided at the upstream end of the barrier.