JPH07115877B2 - Continuous glass forming method and apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for continuously forming glass having a predetermined cross-sectional shape and an apparatus for carrying out this method.

[Conventional technology]

A glass continuous molding method of this type is known from Japanese Patent Publication No. 54-13246. In the case of this method, a molten glass is poured from an outflow pipe into one end of a groove-shaped mold which is horizontally arranged and has an open upper part, and the upper surface of the glass has a predetermined surface shape when it is in a softened state. Glass is continuously molded by continuously striking it with a plate at a constant pressure and continuously pulling out the molded glass from the other end of the mold.

[Problems to be Solved by the Invention]

This conventional method has the following problems with respect to fluctuations in the flow rate of the molten glass because the softened glass is continuously punched by a metal plate to be molded.

(1). When the flow rate exceeds a predetermined amount, the softened glass between the outflow pipe and the metal plate rises, and the thickness of the formed glass increases.

(2). If the flow rate drops below the specified amount,
There is less glass in the softened state between the outflow pipe and the metal plate, the upper surface of the molded glass does not hit the metal plate, the corner between the surface and the side of the glass becomes round, and the thickness becomes thin. .

The present invention has been made in order to solve the above problems, and its object is a continuous glass forming method capable of forming a glass having good shape accuracy without being influenced by fluctuations in the flow rate of molten glass. And to provide the device.

[Means for Solving the Problems]

In order to achieve this object, the continuous molding method of the glass according to the present invention, the molten glass is supplied to the molding die from one end of the molding die having a cylindrical shape, and the molten glass is filled in the molding die. It is characterized in that the molten glass is cooled and hardened in the forming die and continuously drawn from the other end of the forming die.

Furthermore, the glass continuous forming apparatus according to the present invention comprises a mold having a cylindrical shape having the same cross-sectional shape as the cross-sectional shape of the glass to be formed, one end of which is connected to the molten glass outflow pipe. A cooling passage, which is provided in the molding die, for passing a cooling medium, and is inserted into the molding die from the other end of the molding die,
The front end face is provided with a die having a coupling means with glass. In this case, the molding die may be divided into an upper die and a lower die, and the lower die may be connected to the die so that it can be pulled out together with the die. Further, it is desirable that the receiving portion of the molding die be provided with a heating device.

In addition, in the present invention, the molding die formed into a cylindrical shape means a molding die whose periphery is closed, and the internal space thereof, that is, the cross-sectional shape of the molding chamber, is a circle, a square, a rectangle, a triangle, an ellipse. The shape and the like or other shapes may be used.

〔Example〕

 Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 and FIG. 2 show that a round bar-shaped glass is molded.
A glass continuous forming apparatus according to a first embodiment is shown. 1 is a longitudinal sectional view of the molding apparatus during glass molding, and FIG. 2 is a transverse sectional view taken along line II-II of the molding apparatus of FIG. In FIGS. 1 and 2, A is a table on which the molding apparatus is placed. Further, 1 is an outflow pipe connected to a glass melting furnace (not shown), and 2 is a molten glass flowing in the outflow pipe 1. The outflow pipe 1 is made of, for example, platinum or a platinum alloy, and the molten glass 2 is, for example, flint glass (softening point 480 ° C., transition point 435 ° C.). The outflow pipe 1 is surrounded by a heat insulating material 3 made of a ceramic heat resistant fiber or the like.

The outlet end of the outflow pipe 1 is fitted and connected to the receiving portion 4 so that the molten glass 2 does not leak. This receiving part 4 forms the inlet part of the molding die 5 behind it, and the passage 4a therein
Are continuously expanded from the cross-sectional area of the outflow pipe 1 to the cross-sectional area of the molding die 5. Since the receiving portion 4 is separated from the molding die 5, heat conduction between the receiving portion 4 and the molding die 5 having a low temperature is suppressed, and the temperature is kept higher than that of the molding die 5. In addition,
When it is desired to positively increase the temperature difference between the receiving portion 4 and the molding die 5, the receiving portion 4 is made of a material having a small thermal conductivity (for example, ductile) and the molding die 5 is made of a material having a large thermal conductivity (for example, graphite). Alternatively, the receiving portion 4 may be provided with a heating element.

The cylindrical molding die 5 connected to the receiving portion 4 has a molding chamber 5a having the same cross-sectional shape as the cross-sectional shape of the glass 2'to be molded and having a closed periphery. Therefore, in the case of the first embodiment, the forming chamber 5a has the same circular cross section as the contour of the round bar shaped glass 2 '(see FIG. 2). The length of the molding die 5 is determined according to the curing characteristics of the glass 2 ', and in particular, the temperature at which the molding glass 2'exits from the molding die 5 is approximately the transition point (for example,
435 ℃) or less. Furthermore, the mold 5
Alternatively, the atmosphere around it is heated to a predetermined temperature (for example, about 400 ° C.) by a heating device (not shown).

A cooling passage 6 is formed in a portion of the molding die 5 near the receiving portion 4, and the cooling passage 6 is connected to a cooling medium supply device (not shown) via a cooling pipe 6a. Therefore, the temperature of the molding die 5 is lower than the predetermined temperature (for example, about 400 ° C.) near the cooling passage 6. As the cooling medium, for example, room temperature air, water, a mixture of air and water, or the like is used. The forming die 5 shown in the figure is formed integrally,
The cooling passage 6 may be divided and formed so that the cooling passage 6 can be easily formed. In that case, the entire molding die 5 may be divided and formed, or only the range having the cooling passage 6 may be divided and formed. Further, the molding die 5 uses the holding table 5b to form the table A of the molding apparatus.
It is fixedly held on.

A die 7 is inserted into the molding die 5 from its outlet side.
The die 7 has substantially the same cross-sectional shape as the forming chamber 5a of the forming die 5, and is provided with a tail-shaped projection 7a on its front end surface for connecting with the forming glass 2 '. Since the molded glass 2'is solidified and connected to the die 7 by the protrusion 7a, the molded glass 2'can be pulled out of the die 5 by pulling the die 7 in the direction of the arrow 8 in FIG. Mold 7
A conveyor (not shown) and a tunnel type annealing furnace are provided behind (on the right side in FIG. 1), and the molded glass 2 ′ is pulled out from the mold 5 and then conveyed into the annealing furnace by the conveyor.

Next, a glass forming method by the glass continuous forming apparatus having the above structure will be described.

First, the die 7 is pushed into the die 5 from the right side so that the projection 7a of the die 7 is located at the left end of the forming chamber 5a in FIG. Next, the molding die 5 or the atmosphere around it is heated to about 400 ° C. by a heating device (not shown) and kept at this temperature, and is cooled from a cooling medium supply device (not shown) through the cooling pipe 6a. A cooling medium (for example, normal temperature air) is flown through the passage 6.

In this state, molten glass 2, for example, flint glass of 1020 ° C. (softening point 480 ° C., transition point 435 ° C.) is charged into the molding chamber 5a from a glass melting furnace (not shown) through the outflow pipe 1. After the molten glass 2 is filled, the die 7 is pulled in the direction of arrow 8. The filling of the molten glass 2 is continued during this pulling. The drawing die 7 is pulled at a speed not exceeding the filling speed of the molten glass 2 flowing from the outflow pipe 1 into the forming chamber 5a. That is, the die 7 is pulled at a speed such that the molding chamber 5a is always filled with glass. This speed is, for example, about 60 mm
/ Minute. The glass pulled to the range of the cooling passage 6 is rapidly cooled to a temperature below the softening point (for example, 480 ° C.) and hardened. After pulling out the die 7 further and pulling it completely from the die 5 (at this time, the temperature of the glass 2'has dropped to about the transition point (eg, 435 ° C) or lower), it is conveyed by a conveyor (not shown). It goes through a tunnel type annealing furnace.

After that, the molten glass 2 is continuously supplied to the molding chamber 5a, and the hardened molded glass 2'is continuously drawn out to continuously form a cylindrical glass.

As described above, the die 7 is removed at a speed not higher than the filling speed of the molten glass 2 so that the molten glass 2 always fills the molding chamber 5a.
Since the flow rate of the molten glass 2 does not change even if the liquid level of the molten glass in the glass melting furnace changes or the temperature of the outflow pulp 1 changes,
It is possible to mold glass having a shape that exactly matches the cross-sectional shape of 5a.

Next, the glass continuous forming apparatus according to the second embodiment for forming the plate-shaped (rectangular cross section) glass shown in FIGS. 3 and 4 will be described. FIG. 3 is a vertical cross-sectional view of the glass continuous forming apparatus, and FIG. 4 is a horizontal cross-sectional view taken along the line IV-IV in FIG. In both of these figures, parts that are the same as the parts of FIGS. 1 and 2 are given the same reference numerals.

The continuous glass forming apparatus according to the second embodiment shown in FIGS. 3 and 4 is substantially different from the apparatus according to the first embodiment shown in FIGS. 1 and 2 in the following points. That is, the molding die 5'is divided into an upper mold 5A and a lower mold 5B, and has a molding chamber 5'a having a rectangular cross-sectional shape corresponding to the cross-sectional shape of the glass to be molded. The difference is that the cooling passage 6'is provided only in 5A and the heating element 9 is provided in the receiving portion 4, and the other points are substantially the same. Of course,
Also in this case, the molding die 5'can be integrally formed without being divided, and the cooling passage 6'may be formed so as to extend over the entire circumference of the molding die 5 '. The heating element 9 is, for example, Si
It is a C resistance heating element, and the receiving section 4 is higher than the temperature of the molding die 5 '.
The temperature of the molten glass 2 is increased so that the temperature of the molten glass 2 does not decrease.

Also in the case of the second embodiment, the glass is continuously formed with high shape accuracy similarly to the first embodiment, and is affected by the change of the glass liquid level in the melting furnace and the change of the temperature of the molten glass. Absent.

The embodiments of the present invention have been described above, but the present invention is not limited to these. For example, the protrusion 7a of the die 7
Can be formed in a shape other than the tail shape, and other members may be attached to the die front end surface instead of the protrusion 7a, or grooves may be formed in the die front end surface.

Further, when molding a wide plate or the like, the resistance with the molding die increases when the molded glass 2'is pulled out, so it is better to pull out the lower die 5B together with the die 7. In that case, the punching die 7 and the lower die 5B may be connected by a bolt or the like, or the punching die 7 and the lower die 5B may be integrally formed. In this case, in order to continuously form the shaped glass 2 ', the lower mold 5B must be formed very long.

Further, although the molds 5 and 5'are arranged horizontally in the above-mentioned embodiments, they may be arranged vertically. In this case, the vertical glass withdrawal length is limited by the factory ceiling-floor spacing.

Furthermore, depending on the type of glass to be molded, the mold 5,
The 5'and the receiving portion 4 can be integrally formed.

Further, the tubular molding dies 5 and 5'can be formed in a tube shape other than the cylinder or the rectangular tube of the above-mentioned embodiment. That is, a square,
It can be formed in a triangular shape, an elliptical shape, or the like. Further, the cross-sectional shape of the molding chambers 5a, 5'a and the outer contour of the molding dies 5, 5'can be formed in different shapes.

Further, the molding dies 5, 5 ', the receiving portion 4 and the die 7 can be made of various materials such as cast iron (ductile), graphite, other heat resistant metals, ceramics and the like.

〔The invention's effect〕

The glass continuous molding method and apparatus according to the present invention, in a state where a molten glass is filled in a cylindrical mold, the molten glass is cooled and hardened in the mold so as to be continuously drawn from the other end of the mold. Therefore, it is possible to continuously form glass with good shape accuracy without being affected by changes in the glass liquid level in the melting furnace and fluctuations in the temperature of the molten glass, and the flow rate of the molten glass is tightly controlled. It has the advantage of not having to.

[Brief description of drawings]

1 is a longitudinal sectional view of a glass continuous forming apparatus according to a first embodiment of the present invention, FIG. 2 is a transverse sectional view taken along line II-II of FIG. 11, and FIG. 3 is according to a second embodiment. FIG. 4 is a longitudinal sectional view of the continuous glass forming apparatus, and FIG. 4 is a transverse sectional view taken along line IV-IV in FIG. 1 ... Outflow pipe, 2 ... Molten glass, 2 '... Molded glass, 3 ... Insulation material, 4 ... Receiving part, 4a ... Receiving part passage, 5, 5' ... Mold, 5a, 5'a ... Molding chamber, 5b ... Holding table, 5A ... Upper mold, 5B ... Lower mold, 6,6 '... Cooling passage, 6
a ... Cooling pipe, 7 ... Die, 7a ... Protrusion, 8 ...
Drawing direction, 9 ... Heating element, A ... Stand of molding device

Claims (4)

[Claims] 1. A molten glass is supplied to a molding die from one end of a molding die having a cylindrical shape to fill the molten glass with the molten glass, and the molten glass is cooled and hardened in the molding die. A continuous molding method for glass, which comprises continuously drawing from the other end of the molding die. 2. A mold having a tubular shape, the one end of which is connected to an outflow pipe for molten glass and has the same cross-sectional shape as the cross-sectional shape of glass to be molded, and a mold provided on this mold. An apparatus for continuously forming glass, comprising: a cooling passage through which a cooling medium is passed; and a die having a front end face having a coupling means for glass inserted into the die from the other end of the die. 3. The continuous glass forming apparatus according to claim 2, wherein the forming die is divided into an upper die and a lower die, the lower die is connected to the die and can be drawn together with the die. 4. The continuous glass forming apparatus according to claim 2, wherein the receiving portion of the forming die is provided with a heating device.