JPH0345015B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called float type plate glass manufacturing apparatus, particularly one having a temperature gradient characteristic.

2. Description of the Related Art Float-type devices have been known as plate glass manufacturing devices. This manufacturing equipment fills a bath with molten metal such as tin, pours the molten glass onto the surface of the molten metal to form a band-shaped glass ribbon, and pulls the glass ribbon up to the desired thickness by pulling it up from the rear end of the bath. This is a flat glass.

When manufacturing plate glass using such a float-type manufacturing device, the viscosity η of the glass substrate at the bath inlet must be a value at which surface irregularities disappear in about 1 minute, that is, log η = 3.5 to 4.5. In addition, the viscosity η of the glass ribbon at the bath outlet must be a value that will not cause scratches even if it comes into contact with a pick-up roll provided near the rear end of the bath, that is, log η = 10.5 to 11.5. For example, in the case of FL glass composition,
If the viscosity η at the bath inlet is logη = 4, then the glass substrate temperature at the bath inlet must be 1050°C, and if the viscosity η at the bath outlet is logη = 11, then the temperature of the glass ribbon at the bath outlet is
Must be 600℃. In other words, the temperature difference of the glass ribbon at the bath inlet and bath outlet is 450
Approximately ℃ is required. Therefore, a similar temperature difference is required for the metal bath in contact with the glass ribbon and the atmosphere above the metal bath.

By the way, the tin used as the molten metal is a good conductor of heat, and since it is in liquid form, it easily causes thermal convection, which makes the temperature in the bath uniform.
For this reason, a temperature gradient of only about 40°C can be created per approximately 3m of bath length, and a minimum of 35m is required to create a temperature gradient of 450°C, and the atmosphere above the metal bath is also made uniform by convection. A long metal bath is required to obtain the desired temperature difference. Moreover, when the amount of pulling of the glass ribbon is increased, the speed of the glass ribbon increases accordingly, and the temperature gradient becomes further smaller.

Furthermore, the thickness is adjusted by widening the glass ribbon at a predetermined point in the bath using a top roll or the like.When widening the width, it is necessary to maintain the temperature of the glass ribbon at a specified level. A heater is installed in the area where the room is placed. Therefore, a wide area is heated by the heater. Therefore, the length of conventional baths ranges from 35 m to 70 m. For this reason, this is fine for metal baths for mass production that produce 200 to 400 tons of plate glass per day, but
The following metal baths for small-scale production are extremely uneconomical in terms of equipment costs.

The present invention has been made to improve the above-mentioned conventional problems, and its purpose is to make it possible to obtain the necessary temperature difference between the inlet and the outlet even if the length of the bath is shortened. The object of the present invention is to provide an apparatus suitable for small-scale production, which enables the manufacture of plate glass by the float method using a bath having a compact and simple structure.

In order to achieve such an object, the float type plate glass manufacturing apparatus according to the present invention has a partition hanging in the width direction from the lower surface of the roof covering the metal bath, and a partition in the metal bath opposite to the partition. The gist is that only the paired barriers are provided to protrude upward in the width direction of the metal bath, and the length of the metal bath in the molten glass movement direction is less than 35 m.

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

FIG. 1 is a plan view of a metal bath constituting a plate glass manufacturing apparatus according to the present invention, and FIG. 2 is a longitudinal sectional view of the same manufacturing apparatus.

The metal bath 1 has an oblong shape with a wide upstream part (left side in the figure) and a narrow downstream part (right side in the figure), and a refractory block 3 is attached to the inner surface of a metal outer plate 2. Therefore, a recess 4 for storing molten metal such as tin is formed on the upper surface of the metal bath 1.

Further, at the upstream end of the metal bath 1, there is a spout 5 for pouring out the glass substrate from the melting furnace into the metal bath 1.
A jam block 6 is provided on both sides of the spout 5 to prevent the glass substrate from leaking out to the side. In addition, a replaceable wet back tile 7 is installed on the inside of the upstream wall of the metal bath 1 below the spout 5, and also replaceable restrictor tiles are installed between both sides of the wet back tile 7 and the refractory block 3. 8 is attached so that the width of the glass ribbon can be adjusted.

The entire upper surface of the metal bath 1 is covered with a roof 9. This roof 9 has a fireproof block 11 similar to that described above on the inner surface of a metal outer panel 10.
It consists of a.

Further, a barrier 12 is formed in the width direction on the bottom of the recess 4 of the metal bath 1. This barrier 12 is made of a heat-resistant material that is not corroded by the molten metal, and its upper end is positioned slightly below the surface S of the molten metal filling the recess 4 (shown by the imaginary line in FIG. 2). There is. On the other hand, the roof 7 also has a partition 13 extending downward.
has been established. This partition 13 is made of the same material as the refractory block 11, and its mounting position is approximately the same as the barrier 12 with respect to the length direction of the metal bath 1, that is, the moving direction of the glass ribbon. By doing so, the upper space of the bath 1 surrounded by the roof 7 is divided into a plurality of areas by the partitions 13.

A heater 14 and a cooler 15 are arranged in a predetermined area among the divided areas, and in the area where the heater 14 is arranged, the ribbon width is expanded with a top roll 16 while heating the glass ribbon, and the thickness is adjusted. I try to do this. Additionally, a monitoring window 17 is formed at a predetermined location on the side wall of the device.

FIG. 3 is a sectional view showing the mounting structure of the barrier 12, in which fireproof cement 18 is placed on the upper surface of the metal outer panel 2 so that the fireproof blocks 3 are not in contact with each other.
Ram and fix these fireproof blocks 3...
A groove 19 is formed in the upper surface of a predetermined block in the width direction, and the lower part of the wedge-shaped barrier 12 is fitted into this groove 19. That is, the bottom surface of the groove 19 is larger than the opening area of the upper surface, and the lower part of the barrier 12 that fits into the groove 19 is also shaped to widen toward the end. Even if it is composed of small objects, it will not stand out.

4 and 5 show different embodiments of a barrier and a partition, respectively. The barrier 22 shown in FIG. 4 is a carbon tube 24 in which a metal 25 with a high specific gravity such as tungsten is inserted. , in this way, the barrier 22
Because its specific gravity is greater than that of tin, which is molten metal, it does not float to the surface. It is therefore sufficient to simply place the barrier 22 in the recess 26 formed in the refractory block 3.

Further, the partition 33 shown in FIG. 5 has a case 34 made of heat-resistant steel filled with fireproof and heat-resistant wool 35, and a pipe 36 through which cooling water flows. By configuring the partition 33 in this way, the temperature gradient of the glass ribbon can be increased.

Next, more preferable specific dimensions of the barrier and partition will be described. First, the widthwise length of the barrier 12 should be equal to the width of the recess 4 of the metal bath, or if the width of the barrier 12 is shorter than the width of the recess 4, the difference should be at most 1000 mm.
within. In this case, a weir that can be inserted from the outside is provided between the side end of the recess 4 and the end of the barrier 12 to adjust the temperature gradient.

Further, the barrier 12 may be made of ductile with a colorized surface.
2 may be installed by providing a dovetail groove in the refractory block and fitting the barrier 12 into this dovetail groove.
If it is attached through the dovetail groove in this way, even a material such as carbon, which has a specific gravity lower than that of tin, can be used as a barrier. Note that the cross-sectional shape of the barrier is arbitrary. Furthermore, the distance (Dmm) between the upper end of the barrier and the tin surface is preferably 30≧D≧2T·ρglagg/ρtin. Here, ρglass is the glass specific gravity, ρtin is the specific gravity of tin, and T is the thickness of the glass ribbon.

On the other hand, it is desirable that the distance between the lower end of the partition 13 and the upper surface of the glass ribbon be as small as possible, but in consideration of workability, 100 mm to 300 mm is appropriate.

In addition, in the illustrated example, the positions of the barrier 12 and the partitions 13 are aligned in the vertical direction to improve workability, but the positions where the barriers 12 and the partitions 13 are provided are not the same as the length of the metal bath 1. They may be arranged to be shifted in the horizontal direction, that is, in the direction of movement of the glass ribbon. By arranging the barrier 12 and the partition 13 so as to be staggered in this way, the temperature gradient can be made smoother.

Next, the device of the present invention and the conventional device will be explained based on FIG. 6.

Figure 6 shows the length of the metal bath (m) on the horizontal axis and the temperature of the glass ribbon (°C) on the vertical axis.
Line segment a shows the temperature gradient of a conventional device with a metal bath length of 35 m and no barrier or partition installed inside.If the temperature _T1 of the glass ribbon at the metal bath inlet is 1050°C, then the temperature gradient at the outlet is 1050°C. The temperature T ₀ of the glass ribbon is 600°C. and line segment b
shows the temperature gradient when the length of the conventional metal bath mentioned above is simply 15 m, and even if the inlet temperature
Even if T ₁ is lowered, the outlet temperature T ₀ becomes higher, and the temperature difference required when applying the float method cannot be obtained. However, in the case of an apparatus having two sets of barriers and partitions as in the present invention, the necessary temperature difference can be obtained even if the length of the metal bath is 15 m, as shown by line c.

Therefore, as is clear from Figure 6, the length of the metal bath is
The required temperature difference can be obtained even if the distance is less than 35 m.

As described above, according to the present invention, a barrier capable of suppressing the convection of molten metal such as tin is provided in the width direction of the metal bath to which the so-called float method is applied, and a barrier is provided on the roof covering the metal bath. The length of the metal bath was reduced to 35 mm by installing partitions to prevent atmospheric convection and prevent the glass ribbon from being heated over the entire surface area by heaters placed above the metal bath.
It is possible to make the temperature difference of the glass ribbon at the bath inlet and bath outlet a predetermined value while keeping the length shorter than m. Therefore, it is possible to obtain plate glass of excellent quality with a short metal bath of less than 35 m, and the necessary temperature difference can be easily obtained, which increases the amount of glass ribbon pulled up. It has many advantages such as greatly improving productivity.

Furthermore, according to the present invention, the metal bath is formed in a length of less than 35 m to achieve miniaturization, and the barrier in the metal bath is only the one that pairs with the partition provided on the roof, so the required temperature can be maintained with the minimum necessary barrier. Therefore, by downsizing the metal bath and simplifying its structure, the cost of the metal bath can be reduced, and the space occupied by the metal bath can be saved, reducing equipment costs. We can provide metal baths suitable for the following small-scale production.

[Brief explanation of drawings]

The drawings show an example of the implementation of the present invention,
FIG. 1 is a plan view of a metal bath constituting a float type plate glass manufacturing apparatus according to the present invention, FIG. 2 is a sectional view of the same float type plate glass manufacturing apparatus, and FIG. 3 is a sectional view showing the barrier mounting structure. FIG. 4 is a sectional view showing another embodiment of the barrier, FIG. 5 is a sectional view showing another embodiment of the partition, and FIG. 6 is a graph comparing the temperature gradients of the manufacturing device according to the present invention and the conventional device. . In the drawing, 1 is a metal bath, 3 and 11 are fireproof blocks, 4 is a recess filled with molten metal, 7 is a roof, and 1 is a refractory block.
2 and 32 are barriers, and 13 and 33 are partitions.

Claims (1)

[Claims] 1. In a plate glass manufacturing apparatus in which molten glass on a metal bath filled with molten metal is poured out to form a ribbon, and this ribbon-shaped glass is pulled up from the rear end of the metal bath, the lower surface of the roof covering the metal bath is A partition is made to hang down in the width direction of the metal bath, and only a pair of barriers facing the partition is provided in the metal bath so as to protrude upward in the width direction of the metal bath. A float-type plate glass manufacturing apparatus characterized in that the length in the glass moving direction is less than 35 m.