JPH10203830A - Production of glass mass and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain glass mass having a good surface quality by removing unevenness of the surface. SOLUTION: In this glass mass-producing method for feeding glass 2 melted in a melting crucible 1 from the nozzle 4 of the melting crucible 1 onto a receiving mold 6 and obtaining the glass mass, an interval between the lower end of the nozzle 4 and receiving face 6a of the receiving mold 6 is set to the shortest distance capable of carrying out separation of molten glass mass 13 from glass flow 5 and proper amount of the molten glass 2 is extracted and then, a plunger 9 approaches or comes into contact with the upper end 4a of the nozzle 4. Thereby, flow rate of glass flow 5 is controlled so as to decrease or stop to separate glass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a glass lump for producing a glass lump used for pressing an optical element or the like from molten glass.

[0002]

2. Description of the Related Art Conventionally, in a manufacturing method for manufacturing a small glass lump for forming an optical element from molten glass, a glass flow flowing out of a molten crucible is cut by a cutting blade.
Since cut marks on the cut surface remain on the surface of the molded product, a method for producing a glass lump without using a cutting blade has been demanded.

[0003] As a method of responding to the above demand, Japanese Patent Publication No.
Japanese Patent Application Publication No. 24525 and Japanese Patent Application Laid-Open No. 7-300199 are disclosed. In these techniques, after a predetermined amount of molten glass is received from a melting crucible on a receiving mold, the receiving mold is lowered at a speed higher than the flow rate of the glass flow from the melting crucible to constrict the glass flow, and the surface tension of the glass is reduced. To separate glass blocks without cutting marks. By performing this operation continuously, a small glass lump is obtained.

[0004]

However, in the above prior art, the glass flow from the melting crucible is lowered at a speed higher than the flow speed of the receiving mold so that the glass flow is constricted and separated by cutting off the surface tension. As a result, the glass flow is pulled in the vertical direction, and the glass is stretched and elongated, so that the heat capacity of the constricted part is reduced, the surface area is increased, and the glass is easily cooled, and the viscous material is formed into a thread-like glass on the surface of the glass lump. There was something I could do. The glass remaining in the form of a thread becomes uneven (may be left as a protrusion without being absorbed) even when absorbed on the surface of the glass lump, which is a factor that deteriorates the surface quality of the glass lens formed using the glass lump. Had become.

In order to descend the receiving mold faster than the falling speed, a descending distance is required, and it is necessary to secure a descending range of the receiving mold and control the ambient temperature. Furthermore, in the above prior art, during continuous production of a glass lump, since the outflow of the glass flow from the melting crucible is not controlled, depending on the outflow of the glass flow and the size of the glass lump to be produced,
The cycle time of receiving the glass block in the mold is determined, and it is synchronized with the operation of other processes such as the cooling process, the molding process and the collection process, or the timing is adjusted,
It was difficult to stop the cycle.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the invention according to claim 1 or 2 is to eliminate irregularities on the surface and obtain a glass ingot having good surface quality. Is to provide a method of manufacturing the same. A third object of the present invention is to provide a manufacturing apparatus for a glass lump, which implements the manufacturing method according to the first or second aspect of the invention and easily adjusts a timing of a step of forming a molten glass lump and another manufacturing step. It is to provide.

[0007]

In order to solve the above problems, the invention according to claim 1 or 2 is to supply glass melted in a melting crucible from a nozzle of the melting crucible to a receiving mold, In the method for manufacturing a glass lump to obtain a lump, the interval between the lower end of the nozzle and the receiving surface of the receiving mold was set to a distance at which the glass flow and the molten glass lump could be separated, and an appropriate amount of the molten glass was extracted. Then, a plunger approaches or abuts on the upper end of the nozzle to control the flow rate of the glass flow. The invention according to claim 3 is
A melting crucible for melting glass, and a glass lump manufacturing apparatus including a nozzle connected to the melting crucible, a plunger whose position is controlled so as to be able to contact and approach and separate from the upper end of the nozzle, and from the lower end of the nozzle. A receiving mold that can be stopped at a distance where the glass flow is not interrupted and that can move up and down, and a control unit that controls operations of the plunger and the receiving mold are provided.

In the operation of the invention according to claim 1 or 2,
The distance between the lower end of the nozzle and the receiving surface of the receiving die is set to a distance at which the glass flow and the molten glass lump can be separated, and after extracting an appropriate amount of molten glass, a plunger approaches the upper end of the nozzle or By controlling the flow rate of the glass flow to decrease or stop in contact with the glass flow, the glass flow and the molten glass lump are caused by the action of the molten glass's own weight, surface tension, and the surface tension of the molten glass lump flowing out onto the receiving mold. And are separated. In the operation of the invention according to claim 2, in addition to the above operation, after the flow-out amount of the glass flow is reduced or stopped, the receiving die is gradually raised to keep the narrowed portion of the glass flow as short as possible. Relieves cooling and thickening of thin parts. In the operation of the invention according to claim 3, a plunger whose position is controlled so as to be capable of coming into contact with and approaching to and separating from the upper end of the nozzle, and a receiving mold that can be stopped and moved up and down from the lower end of the nozzle so that the glass flow is not interrupted, By providing a control unit for controlling the operation of the plunger and the receiving mold, separation of the glass flow and the molten glass lump can easily proceed, and the cycle time can be set freely.

[0009]

1 to 3 show a first embodiment of the present invention. FIG. 1 is a vertical sectional view of an apparatus for manufacturing a glass lump, and FIG.
Fig. 3 is a process diagram of a method for producing a glass lump, and Fig. 3 is a diagram showing a process of separating a glass flow and a molten glass lump.

In FIG. 1, a melting crucible 1 is disposed above a glass lump manufacturing apparatus. The melting crucible 1 is configured to supply a glass charged therein to a melting heater 3 disposed around the melting crucible 1. By heating and melting to 1000-1600 ° C,
The molten glass 2 is stored. On the bottom of the melting crucible 1,
A tubular nozzle 4 is continuously provided, and a nozzle heater 7 is provided around the nozzle.
Are arranged. The nozzle 4 is heated to 900 to 1300 ° C. by the nozzle heater 7 and keeps the temperature so that the glass flow 5 from the melting crucible 1 (the portion where the molten glass 2 flows out of the nozzle 4) does not cool and harden. The glass stream 5 is supplied onto the receiving surface 6a of the placed receiving die 6 to form a molten glass lump 13 (a portion where the molten glass 2 flows out onto the receiving die 6). The position where the receiving die 6 waits is a distance where the glass flow 5 is not interrupted and about 5 to 30 mm below the lower end of the nozzle 4. Around the standby position of the receiving die 6, a receiving heater 14 is arranged to heat the receiving die 6 to the Tg point of the molten glass 2 ± 100 ° C. The receiving die 6 includes a vertical moving device 8 including an air cylinder or the like.
When the receiving mold 6 is heated, it rises to the standby position, and when the molten glass lump 13 on the receiving mold 6 is collected, it descends.

In the melting crucible 1, a plunger 9 having a diameter larger than the inner diameter of the upper end 4a of the nozzle 4 in the range of 5 to 15 mm is disposed, and the upper end thereof is fixed to the upper and lower arms 10. The upper and lower arms 10 are attached to a positioning device 11 having a ball screw, a robot unit, and the like, so that the moving distance between the tip 9a of the plunger 9 and the upper end 4a of the nozzle 4 can be accurately controlled. By lowering the plunger 9 and approaching the upper end 4a of the nozzle 4, the outflow of the molten glass 2 is reduced, and the tip 9a of the plunger 9 is
The glass flow is stopped by contacting the upper end 4a of the glass. In addition, the vertical movement device 8 and the positioning device 11
The cycle controller 12 is connected to the cycle controller 12, and controls the operation time of the process of manufacturing a glass lump.

Next, a method of manufacturing a glass lump using the above-described manufacturing apparatus will be described. First, a glass material before melting is put into a melting crucible 1, and the melting crucible is heated by a melting heater 3 to produce a molten glass 2. At this time, the molten glass 2 flowing into the nozzle 4 is cooled and solidified before the nozzle 4 is heated, and does not flow out of the nozzle 4. The tip 9a of the plunger 9 is moved by the positioning device 11 to the nozzle 4
Is lowered until it contacts the upper end 4a of the molten glass 2 to prevent the molten glass 2 from flowing out. The nozzle 4 is heated by the nozzle heater 7 so that the molten glass 2 can flow out. The above is the preparation stage.

Next, the step of manufacturing a glass lump will be described with reference to FIG. With the rise of the receiving die, the receiving die 6 is raised to a position for receiving the glass flow 5. Here, the operation of separating the glass flow 5 at the lower end of the nozzle 4 from the molten glass lump 13 flowing out to the receiving die 6 and the setting of the interval between the nozzle 4 and the receiving die 6 will be described. First, the glass flow 5 and the molten glass lump 1
(3) The action of the glass flow 5 flowing out of the nozzle 4 to fall downward by its own weight even if the flow rate of the glass flow 5 in the nozzle 4 is controlled (stopped or reduced). The effect that the tip of the glass stream 5 at the lower end tends to be spherical due to surface tension is combined. (C) The effect that the glass lump 13 that has flowed out to the receiving mold 6 attempts to become spherical due to surface tension is combined. Separated.

The distance between the nozzle 4 and the receiving die 6 is in a range of about 5 to 30 mm below the lower end of the nozzle 4, and the viscosity of the glass flow 5, the shape of the receiving die 6, and the required (receiving) The volume of the molten glass lump 13 (supplied to the mold 6) is taken into consideration, and the glass flow 5 at the lower end of the nozzle 4 and the molten glass lump 13 flowing out to the receiving mold 6 due to the effects of (a) to (c) above.
Is set to an interval that separates

The next step after the stage of manufacturing the glass block is shown in FIG.
As shown in FIG. 5, in order to prevent the occurrence of wrinkles of the molten glass lump 13 on the receiving surface 6a of the receiving die 6 by time counting, the receiving die 6 is heated by the receiving die heater 14 for the predetermined time (the temperature of the molten glass 2). (Tg point ± 100 ° C.). When the plunger is raised, the plunger 9 is raised, the upper end 4a of the nozzle 4 is opened, and the outflow of the molten glass 2 is started. An appropriate amount of the molten glass 2 is extracted for a predetermined time by time counting. When the plunger is lowered, the plunger 9 is lowered, and the glass flow 5 is stopped (or the outflow amount is reduced). Due to the time count, the glass flow 5 is naturally constricted due to a decrease in the flow rate, the surface tension is cut off, and the molten glass lump 13 is separated cleanly.

Here, the process of separating the glass stream 5 and the molten glass lump 13 will be described with reference to FIG. (1) The glass stream 5 flows out of the nozzle 4. (FIG. 3A) (Plunger rise in FIG. 2) (2) The glass flow 5 comes into contact with the receiving mold 6. 3 (b) (time count state in FIG. 2) (3) The glass flow 5 spreads along the receiving surface 6a of the receiving die 6. (FIG. 3 (c)) (4) Due to the above-mentioned operations (a) to (c), a constricted portion 15 is formed between the glass flow 5 at the lower end of the nozzle 4 and the molten glass lump 13 flowing out to the receiving mold 6. Occurs. (FIG. 3D) (Plunger lowered in FIG. 2) (5) The constricted portion 15 further develops and becomes thinner. (FIG. 3E) (6) The constricted portion 15 is cut off, and the glass flow 5 at the lower end of the nozzle 4 and the molten glass mass 13 flowing out to the receiving mold 6 are separated. ... Figure 3 (f)

The next step after the production stage of the glass block is shown in FIG.
As shown in (1), the molten glass lump 13 separated on the receiving die 6 by the receiving die lowering is lowered by the vertical moving device 8 and collected. Thereby, a glass lump used for press molding of an optical element such as a lens can be obtained.

The next cycle operation for manufacturing a glass lump is performed by repeating the steps (1) to (3) in FIG. In this cycle operation, the time count is about 5 to 10 seconds.
c, the time count is about 0.2 to 1.0 sec (depending on the size of the glass block), and the time count is 5 to 15 s
ec, and the molten glass lump 13
The cycle time for forming the mold on the receiving mold 6 is about 20
８０80 sec, and can be set longer by adjustment. The above time control is performed by the cycle controller 12.

According to the first embodiment of the present invention, receiving mold 6
Since the receiving die 6 is stopped until the upper molten glass lump 13 and the glass flow 5 are completely separated, the glass flow 5 is not stretched downward, and a thread-like glass is formed on the upper surface of the molten glass lump 13 after the separation. A glass lump having good surface quality can be obtained without any residue. The receiving mold 6 is heated at the time when the mold is heated, when the glass flow 5 is received, and when the glass flow 5
Since the glass is stopped at the time of separation from the molten glass block 13, the space for separating the glasses is narrow, and the temperature control of the atmosphere is easy. Further, since the flow rate of the glass flow 5 can be reduced and stopped, the time (cycle time) required for each production of a glass lump can be adjusted, and synchronization with other preceding and subsequent processes can be easily performed. .

The nozzle according to Embodiment 1 of the present invention is provided immediately below the center of the melting crucible, but is not limited thereto.
A nozzle inlet may be provided on the side of the bottom of the melting crucible in a horizontal direction or an inclined direction, and the middle may be bent so that the lower end of the nozzle becomes vertical. The operating direction of the plunger does not necessarily need to be vertical, and may be any direction as long as the nozzle inlet can be opened and closed.

[0021]

Second Embodiment FIG. 4 shows a second embodiment of the present invention and is a process diagram of a method for manufacturing a glass lump. The basic configuration of the apparatus for manufacturing a molten glass lump according to the second embodiment of the present invention is the same as that of the first embodiment of the present invention. The only difference is that the moving actuator has a positioning accuracy of 0.01 to 0.1 mm. Therefore,
The illustration and description of the apparatus for manufacturing a glass lump are omitted.

Referring to FIG. 4, a method for producing a glass lump will be described. The steps from the raising of the receiving mold to the lowering of the plunger in the preparatory stage and the manufacturing stage are the same as those in the first embodiment of the present invention, and therefore the description thereof is omitted. While the molten glass lump 13 is completely separated from the glass flow 5 from the plunger descent according to the first embodiment of the present invention, the amount of heat retained in the constricted portion 15 of the glass flow 5 is reduced, and the surface area is increased relative to the volume. As a result, the viscosity increases due to cooling. The narrow, relatively high-viscosity portion of the constricted portion 15 is
When absorbed by the surface of No. 3, the surface may become uneven. Therefore, in the first embodiment of the present invention, the time count is performed. In the second embodiment of the present invention, the receiving die 6 is gradually raised with the progress of the constriction, and the constricted portion 15 is raised. The goal is to keep the heat as short as possible. When the separation of the molten glass lump 13 is completely completed, the vertical movement device 8 is driven by lowering the receiving die, the receiving die 6 is lowered, and the molten glass lump 13 is lowered.
Is cooled and solidified and recovered. Thus, a glass lump can be obtained as in the first embodiment of the invention. In the next cycle, the receiving mold rises again.

According to the second embodiment of the present invention, in addition to the effects of the first embodiment, the glass flow 5 and the molten glass lump 1
Since the cooling of the constricted portion 15 can be suppressed as much as possible by gradually raising the receiving mold 6 at the time of separation from the mold 3, the glass viscosity distribution on the surface of the manufactured glass lump is reduced, and a smoother surface without unevenness is obtained. can do.

In the second embodiment of the present invention, the modification shown in the first embodiment of the present invention can be similarly applied.

[0025]

According to the first or second aspect of the present invention,
The glass flow and the molten glass lump are separated by the action of the weight of the molten glass, the surface tension, and the surface tension of the molten glass lump flowing out onto the receiving mold. Lumps can be obtained. According to the second aspect of the present invention, in addition to the above-described effects, the narrowed portion of the glass flow is kept as short as possible, and the cooling and the increase in viscosity of the thinned portion are alleviated. Can be better. According to the third aspect of the present invention, the separation of the glass stream and the molten glass lump can be easily advanced, and the cycle time can be set freely, so that the timing adjustment with other manufacturing steps is facilitated. Can be.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an apparatus for manufacturing a glass lump according to Embodiment 1 of the present invention.

FIG. 2 is a process chart of a method for manufacturing a glass lump according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a process of separating a glass stream and a molten glass lump according to Embodiment 1 of the present invention.

FIG. 4 is a process chart of a method for manufacturing a glass lump according to Embodiment 2 of the present invention.

[Explanation of symbols]

 Reference Signs List 1 molten crucible 2 molten glass 4 nozzle 4a upper end 5 glass flow 6 receiving mold 6a receiving surface 9 plunger 13 molten glass lump

Claims (3)

[Claims] 1. A method for producing a glass lump, wherein glass melted in a melting crucible is supplied from a nozzle of the melting crucible onto a receiving die, and a lower end of the nozzle and a receiving surface of the receiving die are provided. The distance between the glass flow and the molten glass lump is set at a distance that allows separation, and after extracting an appropriate amount of molten glass, a plunger approaches or abuts the upper end of the nozzle to reduce the flow rate of the glass flow or A method for producing a glass lump, wherein the glass is separated by controlling to stop. 2. The receiving die is gradually raised after the flow rate of the glass flow is reduced or stopped.
A method for producing a glass lump as described above. 3. An apparatus for producing a glass lump having a melting crucible for melting glass and a nozzle connected to the melting crucible, wherein a plunger whose position is controlled so as to be able to abut on and close to the upper end of the nozzle. Producing a glass block, comprising: a receiving die that can be stopped and moved up and down at a distance where the glass flow is not interrupted from the lower end of the nozzle; and a control unit that controls the operation of the plunger and the receiving die. apparatus.