JP3077066B2 - Each production method of glass gob and its intermediate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a glass gob and its intermediate from molten glass without using a cutting blade.

[0002]

2. Description of the Related Art Various methods have been proposed for producing a glass gob by cutting molten glass without using a cutting blade, since cutting the molten glass with a cutting blade causes scratches and stains on the surface. For example, Japanese Patent Application Laid-Open No. 2-345
No. 25 and JP-A-2-14839 are known. A method for manufacturing a glass gob disclosed in Japanese Patent Application Laid-Open No. 2-34525 is a method for receiving molten glass flowing down from an outflow pipe in a molding die, and forming the molding die when a predetermined amount of molten glass is cast into the molding die. The molten glass that flows down and the cast molten glass are cut and separated by rapidly descending to produce a molten glass lump (hereinafter, referred to as a glass gob intermediate). Then, the glass gob intermediate is cooled and solidified to a softening point or lower in a molding die, and the solidified product (hereinafter, referred to as a glass gob) is taken out from the molding die, heated, and press-molded to obtain a product having a desired shape such as a lens and a prism. Is made. On the other hand, a method for manufacturing a glass gob disclosed in Japanese Patent Application Laid-Open No. 2-14839 discloses a method for manufacturing a glass gob intermediate by dropping molten glass from an outflow pipe into a molding die,
The glass gob is manufactured by cooling and solidifying with a gas such as an inert gas.

[0003]

As described above, Japanese Unexamined Patent Application Publication No.
The method for producing a glass gob according to JP-A-34525 discloses a method in which a molten glass flowing out of an outflow pipe and a molten glass poured into a molding die are separated by rapidly lowering a molding die to form a molten glass lump, that is, a glass gob intermediate. The glass gob is manufactured by manufacturing and cooling it. Therefore, an elongated portion is formed at the torn portion of the glass gob intermediate, and since this portion is elongated, it cools quickly and has a high viscosity, so that when it is later absorbed by the glass gob intermediate, an inhomogeneous portion is formed. I do. Then, there is a problem that the heterogeneous portion generates striae inside the glass gob obtained by cooling the glass gob intermediate. The method for manufacturing a glass gob disclosed in Japanese Patent Application Laid-Open No. 2-14839 is to cut and separate molten glass by dropping and to make the glass into a spherical shape by using surface tension, thereby absorbing the elongated and elongated cut portion. However, when the viscosity of the glass gob intermediate to be dropped is high, the surface tension of the glass gob becomes small, and the cutting performance decreases. Therefore, the separation of the glass gob intermediate is not instantaneous, and the glass gob intermediate falls in a state of being connected to the molten glass flowing down from the outflow pipe in a thin thread form. In other words, the glass gob intermediate is in a state where the thread is pulled from the upper molten glass. The glass gob intermediate at the time of this stringing state falls while pulling a thread from the upper molten glass, so that although the stringing portion is eventually absorbed by the glass gob intermediate, it is obtained. The resulting glass gob intermediate produces thread-like non-uniformities.
Then, as described above, there is a problem that striae are generated inside the glass gob obtained by cooling the glass gob intermediate.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to cut molten glass without using a cutting blade. It is an object of the present invention to provide a method for producing a glass gob and an intermediate thereof which can prevent the occurrence of defects such as dirt and striae.

[0005]

Means for Solving the Problems The present invention has been made to achieve the above-mentioned object, and a first invention of the present invention is to receive molten glass flowing out of an outflow pipe below the outflow pipe. A method for producing a glass gob intermediate having a predetermined weight, while receiving a distance between a tip of the outflow pipe and a receiving part, at a distance determined based on the weight of the glass gob intermediate, The molten glass having a predetermined viscosity is caused to flow down from the outflow pipe, and the distal end of the molten glass is received by the receiving portion to form a constricted portion in the molten glass. , The molten glass on the front end side of the constricted portion is separated to obtain the glass gob intermediate. According to a second aspect, in the first aspect, the weight of the glass gob intermediate is adjusted by changing a distance between a tip of the outflow pipe and a receiving portion. According to a third invention, in the first or second invention, the viscosity of the molten glass flowing down from the outflow pipe is adjusted by controlling the temperature of the outflow pipe. In a fourth aspect based on the first, second or third aspect, the viscosity of the molten glass flowing out of the outflow pipe is 35 poise or more. In a fifth aspect based on the first, second, third, or fourth aspect, the outer diameter of the tip of the outflow pipe is 2.0 to 5.4 mm, and the inner diameter of the outflow pipe is 1.0 to 2 mm. .0 mm. In a sixth aspect based on the first, second, third, fourth, or fifth aspect, after the receiving portion is moved to a position for receiving the molten glass, the molten portion flows down from the downflow pipe by the receiving portion. The step of receiving the glass to obtain a glass gob intermediate, the step of moving the receiving portion receiving the molten glass from the position where the molten glass is received is sequentially repeated using a plurality of receiving portions, and a glass gob intermediate having a predetermined weight is formed. It is characterized by being manufactured continuously. According to a seventh aspect of the present invention, the first, second, third, fourth,
The glass gob is produced by cooling the glass gob intermediate produced by the fifth or sixth invention. An eighth invention is characterized in that, in the seventh invention, a glass gob having the above shape is obtained by forming the glass gob intermediate into a desired shape before cooling. A ninth invention is characterized in that, in the eighth invention, the glass gob intermediate is housed in the molding die via a gas layer to perform the molding. Tenth
According to a ninth aspect of the present invention, in the ninth aspect, the mold has a receiving portion for receiving the molten glass and a concave portion for accommodating the glass gob intermediate. In an eleventh aspect based on the tenth aspect, the receiving portion is formed at an opening edge of the concave portion, and the glass gob intermediate is received in the concave portion by separation of the glass gob intermediate. It is characterized by using a molding die. First
A second invention is characterized in that, in the tenth or eleventh invention, the recess has a tapered shape extending upward. The thirteenth invention is directed to the tenth, eleventh, or twelfth aspect.
In the invention, the center line of the outflow pipe receives the molten glass at a position where the center line contacts an opening edge of a concave portion of the molding die, and separates the molten glass. According to a fourteenth aspect, in the tenth, eleventh, twelfth, or thirteenth aspect, the glass gob intermediate housed in the molding die is molded until the surface of the glass gob intermediate reaches a temperature equal to or lower than the softening point. It is characterized in that it is cooled while being housed in a mold.

[0006]

In the first aspect of the invention, the molten glass flowing out of the outflow pipe and descending by its own weight is received by the receiving portion, and a narrow portion is generated. Then, when the molten glass on the distal end side of the constricted portion has a predetermined weight, the distal end side of the constricted portion is naturally separated. The outflow pipe and the receiving portion are kept at a fixed distance until such a separation of the molten glass occurs, so that a glass gob intermediate having a constant weight is always obtained. In the fifth invention, the outer diameter of the tip of the outflow pipe is set to 2.0 to 5.4 mm and the inner diameter is set to 1.0 to 2.0 mm, so that the molten glass does not fall into a dripping state, and scratches, dirt, and pulse are generated. There is no reason. In the sixth invention, by using a plurality of receiving portions, it is possible to manufacture continuously,
Productivity can be improved. In the ninth invention, the gas blown into the concave portion of the mold forms a gas layer between the glass gob intermediate and the concave portion, so that the surface of the obtained glass gob is not scratched or stained. The shape of the glass gob formed at this time is determined by the shape of the concave portion of the molding die. When the concave portion has a trumpet shape, the glass gob is spherical with high sphericity. This is because the air current blown into the concave portion keeps floating without contacting the inner surface of the concave portion and cools and hardens while rotating. When the cross-sectional shape of the concave portion is a concave mirror shape, the glass gob intermediate that has fallen into the concave portion does not rotate and has a shape close to the shape of the molding surface of the mold. In the tenth invention, since the molding die has the receiving portion for receiving the molten glass and the concave portion for accommodating the glass gob intermediate, the apparatus can be simplified.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the drawings. 1 (a) to 1 (e) are longitudinal sectional views of each step of a method for producing a glass gob and an intermediate thereof according to the present invention and a production apparatus used for this method. In this figure, the production apparatus includes an outflow pipe 1 made of platinum or a platinum alloy, the upper end of which is connected to a molten glass tank (not shown).
A heater 3, a thermocouple 4 for detecting the temperature of the outflow pipe 1, and a mold 5 made of heat-resistant steel (for example, stainless steel) disposed below the outflow pipe 1; The temperature is detected by the thermocouple 4 and a temperature control device (not shown) controls the temperature of the outflow pipe 1 based on the detection signal.

The molding die 5 has a receiving portion 6 whose upper surface receives the molten glass 2 flowing down from the outflow pipe 1, and accommodates a glass gob intermediate 9 cut down from the outflow pipe 1 in the center of the upper surface. A concave portion 7 is provided, and a fine hole 8 having an upper end communicating with the concave portion 7 and a lower end opening on the lower surface of the mold 5 is formed in the center of the inside. The concave portion 7 has a tapered shape expanding upward, and the spread angle θ is preferably 5 ° to 3 °.
The angle is set to 0 ° (15 ° in this embodiment), and the inner surface is mirror-finished. The pores 8 allow the gas A for cooling and floating the glass gob intermediate 9 accommodated in the concave portion 7 to pass through the concave portion 7.
It is blown into the inside and is connected to a gas supply source by piping. Examples of the gas A include a gas that does not substantially react with the glass gob intermediate 9, for example, nitrogen, argon gas, and the like. The molding die 5 has a radius of 20 m in this embodiment.
m, a column with a height of 40 mm, and an opening diameter of the recess 7 of 20 m.
m, the width of the receiving portion 6 is set to 10 mm, and the inner diameter of the pore 8 is set to 3 mm. The molding die 5 having such a configuration is disposed below the outflow pipe 1 by a distance h and its center is shifted from the center of the outflow pipe 1 by the opening radius of the concave portion 7. Therefore, the center line of the outflow pipe 1 is in contact with the opening edge of the recess 7.

Next, a method for producing a glass gob and an intermediate thereof by the production apparatus having the above configuration will be described. First, the molten glass 2 is caused to flow down from the outflow pipe 1 (FIG. 1).
(A)). The molten glass 2 flowing down from the outflow pipe 1 is heated by the heater 3 and controlled to have a desired temperature and viscosity. Until the production of the glass gob after this step, the gas A which does not substantially react with the glass gob intermediate 9 is supplied into the concave portion 7 of the mold 5 through the pores 8. The molten glass 2 flowing down from the outflow pipe 1
The leading end is received by the receiving portion 6, the middle portion is narrowed and gradually narrowed (FIG. 1 (b)), and when the weight reaches a certain value, the narrowest portion of the narrowed portion 12 flows from the molten glass 2 flowing down by surface tension. The glass gob intermediate 9 is obtained (FIG. 1 (c)). Since the surface of the glass gob intermediate 9 immediately after the cutting is maintained at a temperature equal to or higher than the softening point, the cut portion 13 where the thread is pulled is lowered by its own weight and surface tension, and is absorbed by the glass gob intermediate 9. In addition, approximately half of the glass gob intermediate 9 on the receiving portion 6 has the concave portion 7.
1, when separated from the flowing molten glass 2, it slides down and is accommodated in the recess 7 (FIG. 1).
(D)). If the distance h between the outflow pipe 1 and the receiving portion 6 is too short, separation by surface tension cannot be performed, and if it is too long, the molten glass 2 drops, so that the viscosity of the molten glass 2 and the outer diameter of the outflow pipe 1 It is appropriately determined in consideration of the inner diameter and the like. Further, when the distance h is shortened, the time until the molten glass 2 is separated becomes longer, and the obtained glass gob intermediate 9
Weight is increased. Conversely, when the distance h is increased, the weight of the obtained glass gob intermediate 9 decreases. Although the glass gob intermediate 9 is indefinite immediately after falling, it is received by the above-mentioned gas A blown up in the concave portion 7,
By rotating in a slightly floating state with little contact with the inner surface of the concave portion, the shape gradually becomes spherical. Then, the glass gob intermediate 9 is cooled while floating in the concave portion 7 and the surface thereof is cooled to a temperature below the softening point, whereby the glass gob 14 is cooled.
(FIG. 1 (e)). The molding die 5 is used for the outflow pipe 1
Upon receiving the glass gob intermediate 9 separated and formed by the dropping of the molten glass 2 flowing down from the pipe, it moves horizontally in the horizontal direction at the same time, and a new empty mold moves below the outflow pipe 1 and stops. Prepare for intermediate.

(Embodiment 1) As a molten glass 2, a lead silicate glass whose components are intensely volatile is used. The inner diameter of the outflow pipe 1 is 2 mm, the outer diameter of the tip is 5 mm, and The distance h was 18 mm, the temperature of the molten glass 2 was maintained at 1000 ° C. and the viscosity was about 80 poise by the heater 3, and 1.0 liters of nitrogen A
Was blown through the glass gob intermediate 9 to produce a spherical glass gob 14. The weight of the glass gob 14 thus obtained was 280 mg. In addition, there was no quality defect such as striae inside, and it was preferable as a glass gob. Next, as Examples 2 to 6, the type of the molten glass 2, the inner diameter of the outflow pipe 1, the outer diameter of the lower end of the outflow pipe 1, the amount of gas (nitrogen) A blown out from the pores 8,
A glass gob was manufactured by changing the temperature and viscosity of the molten glass 2.

The following Table 1 summarizes the above Examples 1 to 6. In all Examples, the judgment results were good, and no occurrence of scratches, stains, striae, etc. was found on the glass gob.

[0012]

[Table 1]

The fluorophosphate glass used in Example 2 is as follows:
Since the component volatilization is extremely severe, the temperature was set to a low temperature at which there is a risk of devitrification when the temperature is further reduced. However, since the components still volatilize somewhat, the molten glass 2
Could not be measured accurately. However, there was no practical problem since the alteration due to the volatilization of the components was present only on the very surface of the obtained glass gob 14 and there was no striae or the like inside. In Examples 3 to 6, the distance h from the tip of the outflow pipe 1 to the molding die 5 (receiving portion 6) was changed. As a result, in Examples 3 to 6, by changing the distance h, the weight of the glass
It could be adjusted to ３370 mg. In addition, the glass gob was preferable as a glass gob without causing scratches, dirt, striae and the like.

Next, the present inventor manufactured a glass gob according to the conventional technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. Hei 2-14839 in order to compare the method of the present invention with the conventional method. In this prior art, a glass gob is formed by simply causing molten glass to flow down, separate, and drop into a mold without providing a receiving portion 6 according to the present invention. The type of molten glass, the inner diameter of an outflow pipe, the outflow pipe In Example 1 above, the outer diameter of the lower end and the amount of gas (nitrogen) blown out from the pores were determined.
6 were obtained, and the determination results shown in Table 2 below were obtained.

[0015]

[Table 2]

As is clear from the determination results in Table 2, striae frequently occurred in the glass gobs of Comparative Examples 1 to 6. In conclusion, the present invention provides for receiving the molten glass 2 even when the viscosity of the molten glass 2 is not very low.
And the cutting of the molten glass 2 by the surface tension can be completely completed, and sufficient time can be given to absorb the cut portion in the stringing state. Therefore, unlike the related art, it is possible to prevent the generation of an inhomogeneous portion. Things. Therefore, it is not necessary to make the viscosity of the molten glass 2 very low.
Could be relatively lowered. For this reason, it has become clear that the present invention is particularly useful for glass in which components are highly volatile.

FIGS. 2 to 7 show other embodiments of the receiving portion 6 used in the present invention.

2 (a) and 2 (b), a receiving portion 6 which forms the same plane as the upper surface of the molding die 5 is integrally provided on a part of the outer periphery of the molding die 5, and the receiving portion 6 is provided on the receiving portion 6. The fallen glass gob intermediate 9 is dropped into the recess 7 by a push rod 20 which can move forward and backward.

FIG. 3 shows a modification of the embodiment shown in FIG. 2 in which a ring-shaped receiving portion 6 is fitted and fixed to the outer periphery of a molding die 5.

FIG. 4 shows that the receiving part 6 is fixedly disposed separately from the molding die 5 directly below the outflow pipe 1 and above the molding die 5, and the glass gob intermediate body 9 dropped on this receiving part 6 is passed through the nozzle 21. The gas is injected into the recess 7.

FIG. 5 shows that the receiving portion 6 is disposed above the molding die 5 directly below the outflow pipe 1 so as to be rotatable up and down around a shaft 22. The receiving portion 6 is shown by a two-dot chain line from a horizontal state. The glass gob intermediate 9 is dropped into the recess 7 by being inclined as shown.

FIG. 6 shows a modification of the embodiment shown in FIG. 1, in which a receiving portion 6 provided on the upper surface of a molding die 5 is formed on a slope inclined toward the center of the molding die 5.

FIG. 7 shows the upper surface of the molding die 5 as the receiving portion 6, and when the glass gob intermediate 9 on the receiving portion 6 is moved into the concave portion 7, the molding die 5 is rapidly moved horizontally in the direction of the arrow to reduce the inertia. The glass gob intermediate 9 is dropped and stored in the concave portion 7 by utilizing. In this case, a plurality of molds 5 are arranged at equal intervals in the circumferential direction on the outer peripheral portion of the upper surface of the turntable, and the turntable is configured to be intermittently rotated by a predetermined angle. Therefore, the glass gob intermediate 9 may be dropped using this rotation.

In the present invention, the receiving portion 6 and the receiving portion 6
The method of transferring the glass gob intermediate 9 into the recess 7 from is not limited to the above-described embodiment, and various modifications and changes can be made without departing from the gist of the present invention. The present invention also provides a glass gob 1 by storing a glass gob intermediate 9 in a mold 5 and cooling it with gas A.
4 is manufactured, but the present invention is not limited to this, and it may be left on the receiving portion 6 and naturally cooled.

[0025]

As described above, in the method for manufacturing a glass gob intermediate according to the present invention, the distance between the tip of the outflow pipe and the receiving portion is fixed to a distance determined based on the weight of the glass gob intermediate. The molten glass having a predetermined viscosity is caused to flow down from the outflow pipe while receiving the tip of the molten glass by the receiving portion, and a constricted portion is formed in the molten glass. When a certain weight is reached, the glass gob intermediate is manufactured by separating the molten glass on the tip side from the constricted portion, so that a glass gob intermediate having a constant weight can always be obtained. In other words, if the distance between the outflow pipe and the receiving portion is kept constant, the molten glass received by the receiving portion will be cut off naturally at the tip side from the constricted portion at a predetermined weight and separated from the outflow pipe, so that the weight is constant. A glass gob intermediate can be produced. In the method for manufacturing a glass gob according to the present invention, a gas is blown into the concave portion of the mold during the cooling of the above-mentioned glass gob intermediate so that the glass gob intermediate is floated. be able to. Further, since the receiving portion for receiving the molten glass and the concave portion for accommodating the glass gob intermediate are provided in the mold, the manufacturing apparatus for the glass gob and the intermediate can be simplified.

[Brief description of the drawings]

1 (a) to 1 (e) are longitudinal sectional views of each step of a method for producing a glass gob and an intermediate thereof according to the present invention, and a production apparatus used for this method.

FIGS. 2A and 2B are a cross-sectional view and a plan view showing another embodiment of a receiving portion used in the present invention.

FIG. 3 is a plan view showing a modification of the receiving portion shown in FIG.

FIG. 4 is a sectional view showing still another embodiment of the receiving portion of the present invention.

FIG. 5 is a sectional view showing still another embodiment of the receiving portion of the present invention.

FIG. 6 is a sectional view showing a modification of the embodiment shown in FIG. 1;

FIG. 7 is a sectional view showing still another embodiment of the receiving portion of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outflow pipe 2 Molten glass 3 Heater 4 Thermocouple 5 Mold 6 Reception part 7 Depression 8 Pores 9 Glass gob intermediate 14 Glass gob

Claims (14)

(57) [Claims] 1. The molten glass flowing out of an outflow pipe,
And received by receiving portion disposed below the outflow pipe,
A method for producing a glass gob intermediate having a predetermined weight, wherein a distance between a tip of the outflow pipe and a receiving portion is set to the glass gob.
Maintain a fixed distance based on the weight of the intermediate
First, molten glass having a predetermined viscosity is allowed to flow down from the outflow pipe.
And the tip of the molten glass is received by the receiving portion.
A constriction is formed in the glass, and
When the weight of the molten glass reaches a certain weight,
Make sure that the molten glass on the tip side
A method for producing a glass gob intermediate, comprising obtaining the glass gob intermediate. 2. The weight of the glass gob intermediate is
Adjust by changing the distance between the tip of the outlet pipe and the receiving part.
The method for producing a glass gob intermediate according to claim 1, wherein 3. Controlling the temperature of said outlet pipe.
Control the viscosity of the molten glass flowing down from the outflow pipe.
The method for producing a glass gob intermediate according to claim 1 or 2, wherein: 4. A molten glass flowing out of the outflow pipe.
Wherein the viscosity is 35 poise or more.
Item 10. The method for producing a glass gob intermediate according to item 1, 2 or 3 . 5. An outer diameter of a tip of the outflow pipe is 2.0 to 2.0.
5.4 mm, the inner diameter of the outflow pipe is 1.0 to 2.0 m
The method for producing a glass gob intermediate according to any one of claims 1 to 4, wherein m is m . 6. The receiving part is moved to a position for receiving molten glass.
After moving, it flows down from the downflow pipe by the receiving part
Upon receiving the molten glass, a glass gob intermediate is obtained.
Move the receiving part that received the lath from the position that receives the molten glass
Is sequentially repeated using a plurality of receiving portions, and a predetermined
The method for producing a glass gob intermediate according to any one of claims 1 to 5, wherein the glass gob intermediate having a weight is continuously produced. 7. The method according to claim 1, wherein
A method for producing a glass gob, comprising cooling a glass gob intermediate produced by the method described above to produce a glass gob. 8. The process until the glass gob intermediate is cooled
A glass gob having the above-mentioned shape by being formed into a desired shape in between
The method for producing a glass gob according to claim 7, wherein 9. A glass gob intermediate using a mold.
The above-mentioned molding is carried out while being housed in the mold through a gas layer.
The method for producing a glass gob according to claim 8, wherein 10. The mold receives the molten glass.
It has a receiving portion and a concave portion for accommodating the glass gob intermediate.
The method for producing a glass gob according to claim 9, wherein: 11. The receiving portion is formed at an opening edge of the concave portion.
The glass gob intermediate is separated by the glass
Sgob intermediate is stored as falling into the recess
The glass according to claim 10, wherein a mold is used.
Sugob manufacturing method. 12. The recess has a tapered shape extending upward.
The glass according to claim 10 or 11, wherein
Sugob manufacturing method. 13. The molding apparatus according to claim 13 , wherein a center line of said outflow pipe is formed by said molding.
The molten glass is received at a position in contact with the opening edge of the concave portion of the mold.
And separates molten glass
A method for producing a glass gob according to claim 10, 11 or 12.
Law. 14. An intermediate glass gob housed in said mold.
The glass gob intermediate to a temperature below the softening point.
It is characterized in that it is cooled while it is housed in the mold until it reaches
Any one of claims 10, 11, 12, and 13 as a signature
The method for producing a glass gob according to claim 1.