JPH08301621A - Molten glass stock and its production and production unit therefor - Google Patents

Abstract

PURPOSE: To improve glass melting workability, protect molten glass from contamination and prevent glass quality variation by separating the opening to charge a solid glass stock therethrough from the molten glass stock level in a melting tank with a communicating means. CONSTITUTION: A glass melting oven 1 having an opening 12 to charge a solid glass stock therethrough is divided into a melt clarifying section 2 and a discharge section 3 through a partition wall 4 and is made up of a melt clarifying tank 5, a connecting pipe 6, and a discharge tank 7. The temperatures of the melt clarifying tank 5 and the discharge tank 7 are measured by thermocouples 81, 87, respectively, and these tanks are maintained at respective specified temperatures by heating them with the corresponding heaters 82, 88 through respective regulators 83, 89. A glass stock charge tube 13 is inserted through the opening 12 and the lower end of the tube is immersed in the molten glass 10 in the melt clarifying tank 5, thus serving as a communicating means to set the inside and outside of the oven separate from each other. A solid glass stock 21 is charged via the tube 13 into the tank 5 and melted, clarified and homogenized, and then discharged externally from the tank 7 via a discharge pipe 8, and molded into a glass processed product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten glass raw material in which the influence of the atmosphere inside the furnace is avoided when the glass raw material is charged into the glass melting tank, the molten glass liquid level is detected, and the molten glass is stirred. And a method for producing a molten glass raw material and an apparatus for producing a molten glass raw material.

[0002]

2. Description of the Related Art Conventionally, when melting glass in a relatively small glass melting furnace, for example, a scoop or the like is inserted into a high-temperature furnace through an opening provided on the side surface of the furnace, Put glass raw material into the melting tank, or insert ceramic pipe or water-cooled metal pipe such as stainless steel from the opening in the upper part of the furnace, and put glass raw material into the glass melting tank through this pipe are doing.

Further, in order to detect the liquid level of the molten glass in the glass melting tank, in the case of a large tank kiln, radiation such as gamma rays is applied to the molten glass from the outside of the path and the amount of absorption is measured. , The method of knowing the height of the glass liquid surface is adopted, and in the case of a relatively small glass melting passage,
A method has been adopted in which an opening is provided in the furnace body, a needle contact sensor is inserted from there, and it is checked whether or not the tip thereof comes into contact with the liquid surface of the molten glass by electrical conduction.

Further, in order to make the temperature of the molten glass uniform, when the molten glass is stirred, generally, an opening is provided in the upper part of the furnace, and a stirring rod is inserted into the molten glass from the opening. The operation was stirring.

The above glass melting furnace is disclosed in Japanese Patent Laid-Open No. Sho 55.
-140723, JP-A-60-81030, and JP-A-6-345442.

However, as described above, there is a common problem described below only by providing an opening in the furnace body according to its purpose.

[0007]

That is, since it is exposed to a heat rising air flow from the atmosphere in the furnace, the workability is poor and the skill is required for the work. I had to spend a lot of effort and money on it.

In addition to this, there are other problems in each of the above-mentioned operations (injection of glass raw material, measurement of liquid level of molten glass, stirring of molten glass).
First, regarding the introduction of the glass raw material, whether the introduction is from the side of the furnace or from the top of the furnace, the glass raw material that has been introduced is usually directly exposed to the atmosphere in the furnace. Therefore, if the grain size of the glass raw material is small, a part of the raw material will be placed in the convection of the furnace atmosphere and fly into the atmosphere. Further, if the raw material is a lump having a certain size, such as cullet, a part of the raw material is subjected to thermal shock and is crushed and scattered. As a result, in any case, there was a risk of contaminating the molten glass in which bubbles were broken in the furnace or in the glass melting tank.

In particular, when the raw material is charged through the opening in the upper part of the furnace, the thermal ascending air current from the atmosphere inside the furnace becomes intense and the charged raw material easily scatters to the outside of the furnace. was there.

Further, in the case of detecting the liquid level of the molten glass through the opening, since the sensor is continuously inserted during the melting process, the atmosphere leaks to the outside through the gap between the opening and the sensor. In the heat rising airflow at this time,
The volatilization of the glass was promoted, and the quality of the glass such as the refractive index was easily changed. Even when the glass is stirred, the stirring rod is always inserted into the furnace, so the external leakage of the atmosphere from the opening has been a factor of similar quality fluctuations.

The present invention has been made in view of the above circumstances. A first object of the present invention is to improve workability in carrying out the above-mentioned various operations required for glass melting, It is an object of the present invention to provide a molten glass raw material, a method for manufacturing the molten glass raw material, and a molten glass raw material manufacturing apparatus, in which the relationship with the atmosphere in the furnace is improved in order to facilitate heat countermeasures in the peripheral equipment of the melting furnace. That is, since the opening of the furnace body is opened each time the glass material is charged, the volatile component from the molten glass in the furnace is released to the outside of the furnace each time. Therefore, when the molded product is a glass lens, in particular, when the molded product is a glass lens, the lens optical property, for example, the refractive index of the lens varies.

A second object of the present invention is to achieve an accurate amount of the glass material in addition to the first object when the glass material is charged, and to adjust the amount of the glass material used in the furnace or It is an object of the present invention to provide a molten glass raw material, a method for producing the molten glass raw material, and an apparatus for producing the molten glass raw material, which prevent contamination of the clarified molten glass in the glass melting tank.

A third object of the present invention is, in addition to the first object, in measuring the liquid level of a molten glass raw material, in addition to the first objective, a molten glass raw material for preventing a glass quality variation and An object of the present invention is to provide a molten glass raw material manufacturing method and a molten glass raw material manufacturing apparatus.

A fourth object of the present invention is, in addition to the above-mentioned first object, when stirring the molten glass raw material, the molten glass raw material and the molten glass are provided so as to prevent the quality variation of the glass. It is intended to provide a method for producing a raw material and an apparatus for producing a molten glass raw material. Further, as another object of the present invention, a lens molding method is proposed which can accurately control the optical characteristics of a glass lens. In particular, we propose a lens molding method aiming at obtaining a lens whose refractive index conforms to the desired set refractive index.

Further, the object of the present invention is to mold glass products,
In particular, we propose a lens molding method capable of providing a glass lens with good quality.

That is, conventionally, when the glass material is charged into the melting tank in the glass melting furnace, the window of the melting furnace is opened and the glass material is charged through the window. When falling into the molten glass, the molten glass scatters, and a phenomenon occurs in which the gas in the melting tank is entrained as the scattered molten glass falls. The entrained gas will result in bubbles remaining in the lens of the molded part.

The air bubbles in the lens adversely affect the refraction of the transmitted ray depending on the place of existence in the lens. Further, as an item of quality inspection of the lens of the molded product, there is confirmation of bubbles in the lens by visual inspection, but the present invention proposes a method for manufacturing a glass molded product capable of minimizing the generation of the bubbles. .

Further, when the glass material is charged into the glass melting tank, the glass material charged must be charged into a predetermined position in the melting tank. For example, if the glass material is thrown into the vicinity of the glass outlet of the melting tank without being thrown into a predetermined position, the unmelted state of the glass material occurs.

That is, the glass material is set so as to have a predetermined flow state (glass viscosity) depending on the relationship between the temperature and the time until it moves from the charging position to the outlet.

Therefore, in the conventional method, when the glass material is thrown into the glass melting tank without being put into a predetermined position when the glass material is thrown into the glass melting tank, a part of the glass material reaches a predetermined flow state. As a result, an unmelted state of the glass material occurs in the molded product. In the case of a lens, this phenomenon of unmelted glass material causes a scattering phenomenon of transmitted light rays and a shortage of transmitted light quantity.

The other object of the present invention is to:
This will be specifically described in Examples described later.

[0022]

In order to solve the above-mentioned problems and achieve the object, according to the present invention, a melt used for forming a glass processed product by flowing out from a glass melting furnace to the outside. A glass raw material, the glass melting furnace, a furnace main body having an opening for charging a solid glass raw material in a solid state, and the inside of the furnace main body to a predetermined set temperature for heating and melting the solid glass raw material A heating means for maintaining, a glass melting tank disposed in the furnace body for storing the molten glass raw material in a molten state by the heating means, and a liquid surface of the molten glass raw material in the glass melting tank,
It is characterized in that it comprises a communicating means for making a space between the opening and the opening to be isolated from the liquid surface, and the solid glass raw material is introduced into the glass melting tank through the communicating means.

Preferably, the molten glass raw material is used for forming a glass processed product by flowing out from the glass melting furnace to the outside, wherein the glass melting furnace is a solid glass raw material in a solid state. A furnace main body that has an opening that opens upward for charging and that is internally divided into a melting refining section and an outflow section by a partition section,
In order to heat and melt the solid glass raw material, heating means for maintaining the molten fining part and the outflow part at respective predetermined set temperatures, and for storing the molten glass raw material in a molten state by the heating means, A glass melting tank arranged in the melting and refining section, an outflow tank connected to the glass melting tank and arranged in the outflow section, an outflow pipe provided in the fluid tank, and the glass melting tank The liquid surface of the molten glass raw material in the inside, and a communication means for separating the opening portion from the liquid surface, and the solid glass raw material is charged into the glass melting tank through the communication means. Then, it is introduced into the outflow tank, and outflowed to the outside through the outflow pipe.

In a glass melting furnace having an opening for introducing glass raw material, and for introducing the solid glass raw material into the glass melting tank arranged in the furnace main body through the opening, the solid material supplied through the opening. It is characterized by comprising a communication means for communicating the opening portion with the predetermined region so that the glass raw material is introduced only into a predetermined region of the liquid surface of the molten glass in the glass melting tank.

In this case, the communicating means has the one end led out to the outside through the opening and the other end partially immersed in the molten glass raw material, and the opening is removed from the furnace atmosphere. It consists of a glass raw material injection pipe that shuts off. Further, the glass raw material charging pipe can be provided with a heating means including a temperature sensor and a heater, and as an example,
The glass raw material feeding pipe is electrically conductive, and for heating with a heater for adjusting the temperature thereof, direct electric heating to the glass raw material feeding pipe is used. Further, the glass raw material feeding pipe is preferably a pipe made of a noble metal material such as gold, platinum or rhodium.

Further, the opening is constructed so as to be shielded from the outside by opening and closing the lid, and when the opening is opened, the surface of the molten glass in the glass melting tank is passed through the opening. May be equipped with a supply means for supplying glass to a predetermined area.

Further, according to the present invention, an opening for introducing the glass raw material is provided, and in the glass melting furnace for introducing the glass raw material into the glass melting tank arranged in the furnace through this opening, the glass is separately communicated with the inside of the furnace. Insertion for inserting the sensor for measuring the liquid level of the molten glass from the outside, with the opening of the molten glass, one end of which is led to the outside through this opening and the other end is immersed in the molten glass. Equipped with a tube.

Further, according to the present invention, an opening for introducing the glass raw material is provided, and in the glass melting furnace for feeding the glass raw material into the glass melting tank arranged in the furnace through the opening, it is connected to the inside of the furnace. Equipped with an insertion tube for inserting the molten glass stirring means from the outside in a state in which one end is led out to the outside through this opening and the other end is immersed in the molten glass. ing.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings. First,
FIG. 1 conceptually shows a first embodiment of the present invention, in which a glass melting furnace 1 is divided by a partition wall 4 into a melting refining section 2 and an outflow section 3. Further, the furnace wall of the glass melting furnace 1 including the partition wall 4 is made of refractory bricks, a heat insulating material, etc., and is devised so that high heat during glass melting does not leak to the outside of the furnace as much as possible.

The glass melting tank for receiving and melting the glass raw material is composed of a melting and refining tank 5 corresponding to the melting and refining section, a connecting pipe 6, and an outflow tank 7 corresponding to the outflow section. However, in this embodiment, both are made of platinum.

At the bottom of the outflow tank 7, for example, an outflow pipe 8 made of platinum is attached so that the glass melted to the required viscosity can flow out. Further, a heater 82 is installed between the glass melting tank and the furnace wall so that the melting and refining section 2 and the outflow section 3 can be heated to different and necessary glass melting temperatures T1 and T2, respectively. ing.

The temperature T1 of the melting and refining tank 5 is monitored by a thermocouple 81, and a signal line 85 is sent to the temperature controller 83.
Is input via the power supply unit 8 and the measured temperature Ta and the set temperature T1 are compared and calculated.
Sent to 4. In this way, the heater 82 is appropriately energized to maintain the furnace temperature T1 constant. On the other hand, also in the outflow part 3, a thermocouple 87, a heater 88, and a temperature controller 89 are provided, and heater energization control is performed by a signal line 90 and an output signal 92.

FIG. 2 is a flow chart showing an example of automatic temperature adjustment. First, when this control is started, the temperature inside the furnace is measured by the thermocouples 81 and 87 in step S1 to obtain the measured temperatures Ta and Tb. And sends it to the adjusters 83 and 89.
Next, in step S2, the set temperatures T1 and T2 preset in each controller are compared with the measured temperature. The comparison result in step S2 is calculated in step S3.
If the two are equal, the step S
The process proceeds to step S1 and returns to step S1 to continue control.

On the other hand, if the measured temperature is not equal to the set temperature in step S3, it is determined in step S4 whether the measured temperature is lower than the set temperature, and it is determined to be low. Proceeding to step S5, the heaters 82 and 88 are energized until the temperature reaches the set temperature. If it is determined in step S4 that the measured temperature is not lower than the set temperature, the process proceeds to step S6, and it is determined whether the measured temperature is higher than the set temperature, and the temperature rises. If so, it is determined that some abnormality has occurred, and step S
In step 8, an abnormality occurrence flag is set and the process ends. If it is determined in step S6 that the measured temperature is not higher than the set temperature, it is determined that the measurement temperature is in an undefined state, the process proceeds to step S7, and the processes from step S1 are performed again.

By the above automatic temperature control, each heater 8
2 and 88 are provided, and the melting and refining section 2 and the outflow section 3 are respectively provided at different necessary glass melting temperatures T1 and T2.
Is configured to maintain.

Further, the molten glass 10 is a glass raw material charging pipe 13 inserted into an opening 12 for charging a raw material provided in the upper part of the furnace.
Be introduced via. The glass raw material charging pipe 13 is a communicating means that communicates with the opening 12 and a predetermined region of the surface of the molten glass 10, and the lower end thereof is immersed in the molten glass 10 in the melting and refining tank 5, and The upper end of the flange 1 is led out to the outside through the opening 12.
4 is supported at the edge of the opening 12 and is substantially
In No. 2, the atmosphere inside the furnace is cut off from the outside of the furnace.

In this embodiment, the glass raw material feeding pipe 13 is made of platinum, but it is corrosion resistant to the molten glass and the volatile components of the glass and does not impair the quality of the glass. If necessary, it can be made of a precious metal such as a platinum alloy. For example, rhodium-containing platinum having high strength may be used for the flange portion, and gold-containing platinum that is hard to be wet with glass may be used for the pipe portion.

In the above embodiment, reference numeral 15 is a jogo, 16 is a raw material charging cup, and 17 is the opening 1.
2 is a lid that opens and closes, and when the raw material is not charged, the outer end of the charging pipe 13 is closed instead of the jogo 15, as shown in FIG. Also, the jogo 15 and the cup 16
The lid 17 is made of stainless steel and has an outer cover made of platinum or a platinum alloy. These (15,16,17)
Are each supported by a separate arm 18, 19, 20 and each of these arms is adapted to be operated by a separate drive (not shown).

Further, in the figure, reference numeral 21 is a glass raw material, and reference numeral 22 is a state in which the raw material just charged is not completely melted and is placed on the liquid surface of the molten glass 10 in the glass melting tank. Is shown. Further, reference numeral 23
Is a part of the charged raw material that has adhered to the inner wall of the charging pipe while it is falling in the charging pipe.

Although not shown in the figure, the device for charging the raw material into the cup 17 is designed to automatically weigh a predetermined amount from the raw material stored in the hopper and charge the cup 16.

Next, a mode in which the glass raw material for the optical element is charged and melted using the above-described system will be described with reference to FIGS.
Will be specifically described.

The glass raw material has a specific gravity of 3.05 at room temperature, a glass viscosity of 10 ^1.5 dPa · s at a temperature of 1300 ° C., a glass viscosity of 10 ^1.6 dPa · s at a temperature of 1200 ° C., and a temperature of 1100 ° C. When the glass viscosity is 10 ^1.8 dPa · s, at 1000 ° C. the glass viscosity is 10 ^2.2 dPa · s, at 890 ° C. the glass viscosity is 10 ^2.9 dPa · s, at 610 ° C. the glass viscosity is 10 ^7.6 dPa · s, A glass of BaO—SiO ₂ —B ₂ O ₃ system having a glass viscosity of 10 ¹³ dPa · s at 498 ° C., which is once rough-melted, is used.

In FIG. 1, the temperature of the melting and refining section 2 is 1280 ° C., and the temperature of the outflow section 3 is 2100 ° C.
The temperature is automatically controlled as described above. Further, the glass raw material having the above-mentioned composition is precharged in the glass melting tank (reference numerals 5 to 7), and the melting and refining tank 5
Is a molten glass raw material having a depth of 50 mm, and the outflow tank 7 is a molten glass raw material having a depth of 130 mm. Then, the lower end portion of the charging pipe 13 is immersed in the molten glass 10 to a depth of about 10 mm.

Here, the glass outflow rate was set to 60 g / min, and in accordance therewith, the glass raw material charging condition was set so that 120 g per cup 16 was charged every 2 minutes. In addition, to explain the movement of the device at the time of charging, first, at the time when the previous charging is completed, the charging pipe 13
Has its outer opening closed by a lid 17, as shown in FIG. As described above, the reason for using the lid is to prevent dust from entering the charging pipe from the outside and to prevent heat loss from the inside of the furnace due to radiation.

Next, when the loading time arrives, first, the lid 17 is moved from above the opening of the loading tube 13 and compared to the state of FIG. Then, as shown in FIG.
Is installed on the pipe 13, and then the glass raw material:
The cup 16 containing 120 g moves above the jogo 15, and the cup rotates around the arm 19 to feed the raw material from the cup 16 into the jogo 15. Most of the charged raw materials fall on the surface of the glass melt, and a part thereof adheres to the inner wall of the charging pipe, as indicated by reference numeral 23 in FIG. When the ingredients are put in and the cup is empty, at this point the cup and jogo evacuate, and conversely,
The lid 17 moves again and, as shown in FIG. 3, rests on the outer opening of the charging pipe 13 and closes the opening 12.

As for the raw material charged in the charging pipe, when the inside of the charging pipe was checked at the next charging time, for example, 2 minutes later, the raw material dropped to the liquid surface of the molten glass almost melted. The surface was substantially flat, and most of the raw material adhering to the inner wall of the charging pipe was also melted down to the liquid surface of the molten glass. In addition, since the heat rising air flow rising from the surface of the molten glass through the charging pipe is extremely small, the inside can be easily removed through the charging pipe 13, and the molten glass liquid surface and the charged raw material It was possible to directly visually observe the melting state.

Further, through the opening 12, the inside of the charging tube can be directly video-recorded from the outside without being thermally shielded, or an infrared radiation thermometer can be used without a special cooling mechanism. The temperature of the molten glass can be easily measured.

After that, as a result of repeating the charging of the glass raw material at an interval of 2 minutes, when about 20 minutes have passed since the start of charging (corresponding to the 10th charging), the temperature measured value of the thermocouple welded to the glass melting tank 5 is measured. Is almost in equilibrium, and even if the charging and discharging are continued for a total of 24 hours after that, the measured temperature value is almost constant, and the glass raw material charged into the charging tube does not melt. Then, the situation where it gets stuck is avoided.

Further, the charging device installed on the upper part of the furnace, that is, the jogo 15, the cup 16 and the lid 17, are all
Although it does not have a cooling mechanism such as water cooling, since the heat rising air flow from the furnace is extremely small, even after a 24-hour charging experiment,
The temperature did not rise to such a level that the operation of the device and the safety of the work became a problem.

Further, since the heat rising air flow from the furnace was extremely small, there was almost no scattering of the raw material outside the furnace when the powdery or granular raw material was charged. As a result, a situation in which the amount of molten glass outflows from the outflow tank is changed due to a decrease in the amount of input due to scattering, and also because the predetermined amount is not input, the height of the liquid surface of the molten glass fluctuates. Was avoided.

Further, during the 24-hour charging experiment, the molten glass that is flowed out does not have components such as bubbles or unmelted residue caused by the scattering of the above-mentioned glass raw materials. It is confirmed by inspection of (optical element).
In addition, after the 24 hour charging experiment, the furnace was cooled and the outer surface of the molten glass in the glass melting tank (reference numerals 5 to 7) and the inner wall of the furnace were observed. It was not recognized at all.

Further, as will be described in detail in the third embodiment, it was hardly observed that the liquid surface of the molten glass was wavy outside the charging pipe each time the glass raw material was charged. When the level of the liquid surface is measured via the
Ripples do not propagate or occur at the measurement location,
It was found that the measurement can be performed with high accuracy.

In practicing the present invention, the lower end of the charging pipe is immersed in the molten glass, and the upper end thereof is communicated with the outside while the flange is placed on the edge of the opening 12, and the furnace is connected to the furnace. By devising so that the atmosphere inside does not leak outside, there are virtually no restrictions on the size (thickness or length) or shape of the charging pipe, and the immersion depth of the charging pipe in the molten glass can be adjusted. It is not limited to the required value. That is, for example,
The cross-sectional shape of the charging pipe and the opening for inserting the charging pipe is not limited to the circular shape. Alternatively, as another example, some supporting legs are attached to the lower end portion of the charging pipe, the lower end of the charging pipe is completely dropped into the glass melting tank, and the upper end portion of the charging pipe of the present embodiment is Instead of providing such a flange portion, it is possible to appropriately use a means such as mortar to seal the gap between the upper end portion and the opening 12.

Further, the kind of the glass raw material to be melted is not limited to that of this embodiment, and the same effect can be obtained by appropriately changing the glass pulling amount (= input amount = outflow amount). It goes without saying that it will be done. Further, the melting furnace and the glass melting layer may have a single tank or a structure having three or more tanks communicating with each other.

For comparison with the present invention, the conventional
The following is the result of an experiment in which a glass raw material was introduced in a glass melting furnace having a structure simply provided with an opening. That is, the content of the comparative experiment will be described with reference to FIG. 7. First, there is a difference from the first embodiment of the present invention. The difference is in the structure of how the charging pipe is equipped. It's just a matter. That is, in FIG. 7, the charging pipe 25 is made of alumina, and the lower end portion thereof is configured so as not to be immersed in the molten glass. A flange 26 made of alumina is adhered to the upper portion of the charging pipe with an inorganic material-based adhesive and is placed on the edge of the opening 12. Further, the glass raw material to be melted and the charging conditions were set to be the same as those in the first embodiment.

As a result, when the lid 17 was opened at the time of feeding the raw materials, a very intense heat rising air flow was blown up from the inside of the furnace through the feeding pipe. For this reason, it becomes impossible to visually observe the inside of the charging pipe for a sufficient time.
From inside 5 to above it, as indicated by reference numeral 27,
A considerable amount of raw material has been scattered. Further, when the glass raw material falls on the liquid surface of the molten glass, as shown by reference numeral 28, there is a phenomenon in which the raw material rises due to convection in the furnace, and a part of the raw material is shattered by thermal shock and scattered. I was seen.
As a result, as indicated by reference numeral 29, the inside of the furnace is contaminated,
As indicated by reference numeral 30, it has contaminated the molten glass which has already progressed in defoaming. In addition, as a result of the scattering of the raw materials, the input raw materials that were weighed at an exact angle could not be accurately supplied.

Further, as indicated by the reference numeral 31, it was observed that the liquid surface of the molten glass near the place where the raw material was charged was undulated every time the raw material was charged, and this phenomenon spreads to the periphery. Therefore, when trying to measure the level of the liquid surface, undulation was transmitted to the measurement location, and the measurement could not be performed with high accuracy.

As described above, when the charging pipe showing the method of the present invention is inserted into the molten glass, the volatile components (eg, lithium, potassium, sodium, etc.) of the molten glass in the furnace when the furnace body opening is opened. Release of alkaline components and compounds such as boron) outside the furnace can be minimized. Thereby, the fluctuation of the refractive index of the lens could be prevented. Further, since the pouring position of the glass material can be accurately determined by the pouring tube, the phenomenon of unmelted glass material can be eliminated. Furthermore, the generation of bubbles due to the scattering of the molten glass by the glass material charged by the charging pipe was also eliminated.

Next, although not shown in the figure, the length of the alumina injection pipe used in FIG.
Similarly to the above, the lower end of the charging tube was soaked in the glass melt. As a result, there was almost no heat rising airflow from the inside of the furnace, so the scattering of the raw material outside the furnace was prevented, and when the raw material fell to the melt surface, the scattering of the raw material disappeared, but Since the part of the soaked injection pipe is made of alumina, it was confirmed after a 24-hour injection experiment that the part of the injection pipe near the liquid surface was violently eroded by the molten glass and a little force was applied. It has been torn. Further, the corroded alumina melts into the molten glass, and there is a risk of changing the glass composition and further the quality of the molded product.

Next, as a comparative example with the present invention, a similar experiment was attempted with a conventional structure as shown in FIG. Here, from the opening 32 on the side of the furnace to the cup 33 made of stainless steel.
The raw materials were charged by inserting into a high temperature furnace. Further, the opening 32 closes an opening / closing door (not shown) made of refractory when the raw materials are not charged so that heat inside the furnace does not leak to the outside. Then, when the raw material is charged, this door is opened and the cup 33 containing the glass raw material is charged into the furnace. The cup 33 is attached to the tip of the arm 34, and the arm rotates about the axis in the furnace so that the glass raw material is dropped and supplied onto the molten glass.

The method of charging the raw material into the cup is the same as in the first embodiment of the present invention. Further, the cup or arm was not provided with a built-in cooling device. Further, here, the glass raw material to be melted and the charging conditions were set to be the same as those in the first embodiment.

As a result, when the glass raw material is charged from the side of the furnace, unlike the charging from the upper part of the furnace, the heat rising air flow from the inside of the furnace is considerably reduced, so that the raw material is scattered near the opening 32 on the side of the furnace. However, when the glass raw material fell from the cup to the liquid surface of the molten glass, as shown by reference numeral 35, the raw material was placed on convection in the furnace and soared up, and a part of the raw material was crushed and scattered by thermal shock. There was a phenomenon. As a result, as shown by the reference numerals 36 and 37, the contamination in the furnace and the contamination of the molten glass in which bubbles have already been broken were unavoidable.

As another problem, the temperature of the cup rises as the number of times of charging increases, and even after the 17th charging, even if the cup is taken out of the furnace after the charging, the cup does not cool sufficiently. , In the next stage, a part of the glass raw material put into the cup from the automatic weighing machine melts a little,
It has fused to the cup. To prevent this, it is sometimes good to spray the cup with water, but this time,
If any water is left in the cup, it will cause
The glass raw material adhered to the cup, which hindered the addition of a predetermined amount of raw material.

Further, as indicated by the reference numeral 38, it was observed that the liquid surface near the place where the raw material was charged was undulated every time the raw material was charged, and this phenomenon spreads to the periphery. For this reason, when attempting to measure the liquid level, there is a risk that undulations will be transmitted to the measurement location and the measurement cannot be performed with high accuracy.

In summary, according to the present invention, when the glass raw material is charged, the charging pipe is inserted into the opening for charging the raw material, one end of the charging pipe is immersed in the molten glass, and the other end thereof is immersed. It is important to shut off the atmosphere in the furnace from the outside with the part exposed to the outside through the opening. As a result, heat rising airflow from the inside of the furnace through the charging pipe is avoided, so that a special cooling mechanism is not required for the charging device, and there is almost no scattering of raw materials outside the furnace,
The input amount can be set accurately. Further, it can be seen that the scattering of the raw materials in the furnace can be completely prevented, so that the inside of the furnace and the molten glass in which bubbles have already been broken are not contaminated. Further, it is found that the liquid level outside the charging pipe is hardly wavy each time the raw material is charged, so that the level measurement of the liquid level can be performed with high accuracy. By using a noble metal as the material of the charging pipe, it is possible to prevent the quality variation of the glass.

Next, a second embodiment of the present invention will be specifically described with reference to FIG. Input tube 4 used in this embodiment
In FIG. 5, lead plates 40 and 41 for directly energizing and heating are added to the charging pipe of the first embodiment. In this case, the AC power source 42 supplies electric power to the lead plates. However, the effect of heating is not limited to alternating current, and the same effect can be obtained with direct current. Further, the temperature of the heater due to energization is directly monitored by the thermocouple 43, and the supply power is adjusted through the temperature controller 44. Noble metals such as platinum or platinum alloys are used for the charging pipe 45 and the lead plates 40 and 41. Further, the arrangement position of the thermocouple 43 is set to 10 mm above the liquid surface of the molten glass in the present embodiment, but it is not limited to this position. For example, a plurality of thermocouples are attached in advance at predetermined positions, and The thermocouple at the location with the highest temperature, or vice versa, can be used for control.

The glass melting furnace 1, its heating method, and the glass melting tank are basically the same as those in the first embodiment, and the glass melting tank 10 contains the molten glass 10. In addition, the opening 46 for raw material charging provided in the upper part of the furnace is
Considering the equipment of the lead plate 40, the spacing is slightly widened.

Further, regarding the funnel, the cup, the lid, and their driving devices for charging the glass raw materials,
The same thing as Embodiment 1 was used. In addition, regarding the experimental conditions of charging, melting, and outflow using this system, the glass pulling amount (= input amount = outflow amount) is set to a value larger than that of Embodiment 1, specifically, tripled to 180 g / min. The glass raw material charging conditions were set so that 180 g per cup was charged every minute. Also,
Except for heating the charging pipe 45 by direct energization, the other points are the same as those in the first embodiment.

First, a charging experiment was conducted without directly heating the charging pipe 45 with electricity. The temperature measured by the thermocouple 43 was 1260 ° C. before starting the raw material charging. Here, the raw material charging was started under the above-mentioned condition of 180 g / min. Immediately before the second charging, when the inside of the charging pipe 45 was removed, the upper surface of the initially charged raw material was still raised and was not sufficiently melted. At this time, the measurement temperature of the thermocouple 43 had dropped to 1040 ° C. The charging was continued as it was, but in the third time, the charging material started to be clogged in the pipe 45, and the thermocouple 4
The measurement temperature of 3 has fallen to 860 degreeC. For this reason, the injection was abandoned three times.

On the other hand, as a method of the embodiment of the present invention, the charging pipe 45 is directly heated by energization at 180 g /
We searched for conditions under which the raw materials could be added in minutes. As a result, if the temperature measured by the thermocouple 43 is maintained at about 1100 ° C. or higher (the glass viscosity is equivalent to 10 ^1.8 dpa · s or lower), as an example, 180 hours continuously for 24 hours.
It was possible to charge, melt, and flow out at g / min.

It should be noted that the charging device installed in the upper part of the furnace, that is, the jogo, the cup, and the lid, are not provided with a cooling mechanism such as water cooling, but the heat rising airflow from the furnace is extremely small. Even after the 24-hour charging experiment, no temperature rise that would cause a problem in the operation of the apparatus and in the safety of the work was observed, and this point is the same as in the first embodiment.

Further, as in Embodiment 1, there is almost no scattering of the raw material inside or outside the furnace when the raw material is charged. For this reason, since the predetermined amount is not charged, the height of the liquid surface of the molten glass fluctuates, and the outflow amount of the glass changes, or due to the raw material scattering in the outflowing glass,
No bubbles or unmelted components remained, and it was not observed even after the glass was scattered on the outer surface of the glass melting tank or the inner wall of the furnace. In addition, the point that the liquid surface was not wavy outside the charging pipe each time the raw material was charged was
Is the same as

In practicing the present invention, the lower end of the charging pipe is dipped in the molten glass and the upper end is led out through the opening. Moreover, at the opening, the atmosphere inside the furnace and the outside of the furnace As long as it is designed to shut off, the dimensions (thickness and length) and shape of the charging pipe are not limited, and the depth of immersion in molten glass is not limited.
It is similar to the first embodiment.

Further, the kind of glass raw material to be melted and the glass pulling amount (= input amount = outflow amount) may be changed appropriately, or
It does not matter at all that the melting furnace and the glass melting tank may be a single tank or three or more tanks.

To summarize the above, in the present invention, even if the glass pulling amount (= input amount = outflow amount) is particularly large, the raw material charged by the glass is charged in the manner of the second embodiment. Does not melt and does not clog the dosing tube. In addition, no special cooling mechanism is required for the charging device, and then the charging amount can be accurately set.
Glass can be charged without contaminating the molten glass which has already been defoamed. In addition,
Since the liquid surface of the molten glass does not undulate, the level of the liquid surface can be measured with high accuracy.

Further, the third embodiment of the present invention will be specifically described with reference to FIG. In the third embodiment, the liquid level of the molten glass is measured by using the needle sensor, but the configuration and material of the glass melting furnace 1 and the glass melting tank (reference numerals 5 to 7) are basically the same as those of the first embodiment. Is the same as. Further, on the upper part of the melting and refining section 2, an opening 12 for introducing the raw material and an opening 52 for measuring the liquid level are separately provided. Into the raw material charging opening 12, a platinum charging tube 13 (inner diameter 50 mm) having the same specifications as those used in the first embodiment is inserted. As the raw material charging device, in the present embodiment, a hopper 48 for storing the glass raw material and a charger 49 for weighing and supplying the glass raw material are used. A raw material introduction pipe 50 is provided between the charger 49 and the charging pipe 13, and a flange portion 51 is provided at a lower end portion thereof, which is mounted on the flange portion 14 of the charging pipe 13.
The lower portion of the raw material introducing pipe 50 and the flange portion 51 are both made of platinum, and the upper portion of the raw material introducing pipe is made of stainless steel.

A platinum insertion tube 53 having an inner diameter of 30 mm is also inserted in the opening 52 for measuring the liquid level, the lower end of which is immersed in the molten glass 10, and the upper end thereof is With the flange portion 54 placed on the edge of the opening portion 52, the flange portion 54 is communicated with the outside to shut off the atmosphere inside the furnace from the outside. As a material of the insertion tube 53, a noble metal such as a platinum alloy may be adopted as needed, as long as it has a corrosion resistance against molten glass and volatile components of the glass and does not impair the quality of the glass. .

Further, in order to measure the level of the liquid surface 11 of the molten glass, a platinum needle sensor 55 is used for the insertion tube 53.
Has been inserted. The shape of the needle sensor in this case is a downward conical shape, and the diameter of the bottom surface is 10
mm and height is 25 mm. Further, this sensor portion is welded to the lowermost portion of a platinum shaft 56 having an outer shape of 5 mm. The gap between the shaft 56 and the insertion tube 53 is 12.5 m.
m. The uppermost part of the shaft 56 is attached to the drive shaft 58 via the clamp holder 57. A vertical drive device 60 is attached to a pedestal 59 above the melting furnace so that the drive shaft 58 can be moved up and down. Further, the driving device 60 has a built-in linear scale so that the vertical displacement can be understood. Reference numeral 61 is a glass liquid level controller with a built-in electrical continuity detector, which includes the needle sensor 55 and the insertion tube 5.
When both 3 are in contact with the liquid surface 11 of the glass, electrical conduction occurs. The controller 61 includes
Lead wires 62 and 63 for detecting the presence or absence of conduction between the sensor 55 and the insertion tube 53, a signal wire 64 for obtaining position information from a linear scale built in the driving device 60, and via these wires Based on the obtained information, a power line 65 for moving the needle sensor 55 up and down and a control line 66 for instructing the charger 49 to supply the glass raw material.
And are connected as shown.

Next, a mode in which the glass material for the optical element is charged and melted using the above-mentioned system to measure the liquid level will be specifically described with reference to FIG. The glass raw material used in the third embodiment is the same type of glass as in the first embodiment. Further, the melting and refining section 2 is 1280 ° C.,
The temperature of each of the outflow portions 3 is controlled so as to reach 1100 ° C., and the glass raw materials (reference numerals 5 to 7) are pre-charged with the glass raw materials as in the first embodiment. is there. Here, each of the lower ends of the glass raw material feeding pipe 13 and the insertion pipe 53 is immersed in the molten glass to a depth of about 10 mm.

Next, the driving device 60 of the liquid level meter is driven in a state where the glass does not flow out, and the needle contact sensor 55 is lowered to a height at which conduction is obtained by contacting the liquid surface and the height at this time. The height H0 was measured by a linear scale built in the driving device 60.

Next, the temperature of the outflow pipe 8 is set to 800 to
The outflow rate of glass was arbitrarily set in the range of 1 to 60 g / min by changing it between 1180 ° C. This time,
When the glass raw material is not supplied, the level of the liquid surface 11 of the molten glass decreases at a rate of 0.5 mm / hour to 0.5 mm / minute, and at the same time, the outflow rate decreases as the liquid surface level decreases. It was

Next, with the start of the outflow, the drive device 60 is restarted.
The needle contact sensor 55 was lowered to a height at which electrical conduction was obtained by driving and the contact with the liquid surface, and the height H1 at this time was measured by a linear scale. The cycle of this measurement is 12
Seconds

Next, in the liquid level meter 61, H0 and H1 are compared, and when H0> H1, that is, when H1 is small and the liquid level is low, the difference H0-H1 in the liquid level is compensated. Therefore, the weight of the solid glass raw material is calculated, and the weight is instructed by the charger 49, and the solid glass raw material is charged. The glass weight corresponding to a liquid level difference of 1 mm is 120 g in this embodiment.

On the contrary, when H0≤H1, the solid glass raw material is not added. During the glass spill,
As a result of performing such an operation, even when the glass outflow rate is suddenly changed from 1 g / min to 60 g / min, the fluctuation of the liquid level 11 is kept within ± 1 mm, and due to the fluctuation of the liquid level. Very little change in glass outflow,
It remained at 0.2 to 0.3%.

Here, as described above, the contact sensor 12
Experiment to drive up and down at second intervals (5 times / minute) continuously 1
It was carried out for 20 hours. During this period, the glass outflow amount is 1 to 60 g.
The value was appropriately changed within the range of / minute. Here, as described above, an experiment in which the needle contact sensor was vertically driven at an amplitude of 20 mm in the vertical width and 5 times / minute was continuously conducted for 120 hours. During this period, the glass outflow amount was appropriately changed within the range of 1 to 60 g / min.

The results are as follows. First, the same effect was observed in this embodiment because the glass material charging pipe 13 configured as in Embodiment 1 was used for charging the raw material. That is, as a result of avoiding the heat rising airflow from the inside of the furnace, no problematic temperature rise was observed in the charging device, and no special cooling mechanism was required. Moreover, since the raw material was hardly scattered outside the furnace, the input amount could be set accurately. Further, since the scattering of the raw material in the furnace can be completely prevented, the inside of the furnace and the molten glass in which the bubbles have already been broken are not contaminated. Further, it is important to note that when the level of the liquid surface is measured as in the present embodiment, the liquid surface of the molten glass is hardly wavy outside the charging pipe every time the raw material is charged. It has been found that the measurement can be performed with high accuracy without the occurrence of waviness or generation at the liquid level measurement location.

Also, regarding the level measurement of the liquid level, since the heat rising air flow from the inside of the furnace to the outside of the furnace through the insertion tube 53 is very small, the clamp holder 57 and the drive unit 6 are used.
The temperature of 0 has already reached equilibrium at about 220 ° C. and about 70 ° C. about 10 hours after the start of the experiment, and eventually,
The temperature did not rise above that. Therefore, it was found that the liquid level meter does not require a special cooling mechanism such as water cooling. In addition, the refractive index nd (587.56n
The fluctuation amount of m) was in the range of ± 30 × 10 ⁻⁵ , and the optical element had good quality.

In carrying out the present invention, the lower end of the insertion tube for inserting the level meter is immersed in the molten glass and the upper end is taken out of the furnace so that the atmosphere in the furnace is shut off from the outside of the furnace. If so, there is no restriction on the size (thickness or length) or shape of the insertion tube, and the immersion depth in the molten glass is not limited.

Further, the kind of glass raw material is not limited to that of this embodiment, and the glass pulling amount (= input amount =
Needless to say, even if the outflow amount) is appropriately changed, the same effect as that of the above embodiment can be obtained. Further, it does not matter at all that the melting furnace and the glass melting tank may be a single tank or three or more tanks.

On the other hand, the following is a comparison experiment in which the level of the liquid surface is measured by the conventional method, which is roughly divided into two types. First, to explain the mode of the first experiment, this experimental apparatus is not particularly shown in the drawings,
In the apparatus of Embodiment 3 (FIG. 5), the insertion tube 53 for measuring the liquid level is pulled out, and the inner diameter of the opening 52 is set to 15 to 30 m.
It is the same except that it is reduced to m. As a result,
The gap between the shaft 56 having an outer diameter of 5 mm and the opening 52 is 5 to 12.5 mm over the entire circumference. Further, in the comparative experiment, the glass raw material charging pipe 13 was used in the same manner as in the third embodiment, and the glass raw material, the glass pulling amount, and the liquid level measuring method were set to the same settings as those in the third embodiment.

As a result of this comparative experiment, the heat rising airflow from the inside of the furnace to the outside of the furnace through the opening 52 was intense, so that the temperature of the clamp holder 57 and the driving device 60 was about 15 hours after the start of the experiment. Then, about 34
It exceeded 0-450 ° C and about 125-160 ° C, and the temperature continued to rise. Therefore, it was found that the liquid level meter could not be used for continuous experiments without a special cooling mechanism such as water cooling.

The refractive index nd (5
The fluctuation amount of 87.56 nm) becomes large, and ± 60 to 11
It had reached 5 × 10 ^-5 . This is because the heat rising airflow from the inside of the furnace to the outside of the furnace is intense through the opening 52,
It is considered that the composition of the molten glass was changed because the molten glass component was selectively evaporated under the warm condition, placed on the rising air current and flowed out of the furnace. Further, if the composition changes and the refractive index changes, there is a risk that qualities other than the refractive index, such as optical properties, thermal properties, and chemical properties, may also change.

In a comparative experiment in another mode, contrary to the comparative experiment described above, the liquid level measuring insertion tube 53 was used in the same manner as in the third embodiment. On the other hand, the length of the charging pipe 13 was shortened so that the lower end of the charging pipe 13 was above the liquid surface of the molten glass. The glass raw material, the glass pulling amount, and the liquid level measuring method were set to be the same as those in the third embodiment.

As a result, the heat rising airflow from the inside of the furnace became violent through the charging pipe, and the raw material was scattered inside and outside the furnace. Then, each time the raw material is charged, the liquid level near the position where the material is charged undulates, and, for example, the fluctuation of the liquid level exceeds ± 3 mm, which is transmitted to the level measurement position of the liquid level, resulting in measurement. Cannot maintain the accuracy of ownership, and the change in the glass outflow amount due to the fluctuation of the liquid level is ± 0.4
It has exceeded%. As described above, in the glass melting furnace of the present invention, when measuring the level of the liquid surface of the molten glass, the insertion tube is inserted into the opening for inserting the level meter, and one end thereof is inserted. Dip the molten glass into the molten glass and draw the other end out of the furnace through the opening to shut off the atmosphere in the furnace from the outside of the furnace. The rising airflow is avoided, and the liquid level gauge does not require a special cooling mechanism such as water cooling. Further, there is an effect of preventing the quality variation of glass.

Further, by using the glass raw material feeding pipe, the liquid surface does not wavy outside the feeding pipe every time the raw material is fed, so that the waviness does not propagate or occur at the liquid level measuring location. , The measurement will be highly accurate.

FIG. 6 conceptually shows the fourth embodiment of the present invention. The glass melting furnace 1 and the platinum glass melting tank (reference numerals 67 to 69) are the same as those of the first embodiment. Is basically the same as.

An opening 12 for introducing the raw material is provided on the upper portion of the melting and refining section 2, which is a little longer than that used in the first embodiment. , Inner diameter 50 mm) is inserted. The set of devices used for charging the raw materials is the same as that of the first embodiment including the jogo 15 and the cup 16.

Further, an opening 72 is provided in the upper part of the outflow portion 3 so that a stirring rod 71 for stirring the molten glass can be inserted, and an insertion tube 73 is also inserted therein. . This insertion tube has the lower end portion immersed in the molten glass 74, and the upper end portion thereof has a flange portion 75 provided at the opening portion, like the charging pipe 70 except that the inner diameter is 40 mm. It is led out of the furnace so that it is placed on the upper edge of 72, and the atmosphere inside the furnace is cut off from the outside of the furnace. This insertion tube is also made of platinum,
Corrosion resistant to molten glass and volatile components of glass,
As long as it does not impair the quality of the glass,
It is also possible to make it with a precious metal such as a platinum alloy.

As the stirring blade 76, a spiral blade is used in the fourth embodiment, and the material thereof is platinum. A heat shield plate 77 is attached to the stirring rod 71 at a height of 20 mm above the flange portion 75. This is also made of platinum,
The diameter is 100 mm. Further, although not shown in the drawing, the stirring rod 71 is attached to an electric motor (not shown) and can be rotated at a predetermined speed in the direction indicated by the arrow. The heat shield plate 7 of the stirring rod 71
The length of the upper part of 7 is 200 mm, the outer surface of the stirring rod is covered with platinum, and the outer diameter is 20 mm.
Therefore, the gap between the insertion tube 73 and the stirring rod 71 is 10 mm over the entire circumference.

[0100] Using this system, the mode of use in which the glass raw material for an optical element is charged, melted, and stirred will be specifically described below. The glass raw material used in Embodiment 4 has a specific gravity of 3.74 at room temperature, a glass viscosity of 10 ^1.0 dPa · s at a temperature of 1100 ° C., and a glass viscosity of 10 ^1.8 dPa · s at a temperature of 1000 ° C. , Glass viscosity at 900 ° C. is 10 ^3.0 dPa · s, glass viscosity at 800 ° C. is 10 ^4.8 dPa · s, glass viscosity is 10 ^7.6 dPa · s at 716 ° C., glass viscosity is 10 ¹³ dPa · s at 627 ° C. A La ₂ O ₃ -B ₂ O ₃ based glass having a characteristic of s was used after being subjected to rough melting.

Here, the temperature of the melting and refining section 2 is controlled to 1170 ° C. and the temperature of the outflow section 3 is controlled to 1000 ° C. The platinum glass melting tanks (reference numerals 67 to 69) are pre-charged with the above-mentioned glass raw materials, and the melting and refining tank 67 is a molten glass having a depth of 70 mm, and the outflow tank 69 is deep. The molten glass has a size of 150 mm. Then, the lower end of the charging pipe 70 can be immersed in the molten glass to a depth of about 65 mm, and the lower end of the insertion pipe 73 is immersed to a depth of about 5 mm.

Next, the results of experiments conducted on the apparatus of the fourth embodiment will be described. Here, the stirring rod 71 is 20
The molten glass is stirred at the rotation speed of rpm. Here, the glass outflow rate is set to 40 g / min, and in accordance therewith, the glass raw material charging condition is set to 120 g per cup 16 and the glass material is charged every 3 minutes. The operation of the charging device is the same as that of the first embodiment except that the intervals of the charging time are different. The feeding, melting, stirring, and outflow experiments were conducted continuously for 72 hours.

The results are as follows. First, since the raw material charging was in accordance with the usage mode of the first embodiment, the same effect was observed in this embodiment. That is, as a result of avoiding the heat rising airflow from the inside of the furnace, a problematic temperature rise is not seen in the charging device, so that no special cooling mechanism is required. Also, since there is almost no scattering of the raw material outside the furnace, the input amount can be set accurately, and since the scattering of the raw material inside the furnace can also be completely prevented, the inside of the furnace and the molten glass that has already progressed to the defoaming are Not polluted.

On the other hand, although it is the stirring of the molten glass, the temperature of the lower surface of the heat shield plate 77 is 7 after the start of the experiment because the heat rising air flow from the inside of the furnace to the outside of the furnace through the charging pipe 73 is very small. After ˜8 hours, at about 280 ° C., equilibrium had already been reached, and the temperature of the lower surface of the electric motor (not shown) above it had only reached about 80 ° C. Therefore, it was found that the stirring drive system does not require a special cooling mechanism such as water cooling. Also, the amount of fluctuation of the refractive index nd (587, 56 nm) of the glass that has flowed out through the experiment for 72 hours continuously is in the range of ± 30 × 10 ⁻⁵ , which is a good quality for optical elements. It was

In carrying out the present invention, if the lower end of the insertion tube for inserting the stirring rod is immersed in molten glass and the flange 75 at the upper end cuts off the inside and outside of the furnace, the dimensions of the insertion tube ( There are no restrictions on the thickness and length) and shape, and there is no limitation on the depth of immersion in the molten glass.

Further, the kind of glass raw material is not limited to that of this embodiment, and it is needless to say that the same effect can be obtained by appropriately changing the glass pulling amount (= input amount = outflow amount). Yes. In addition, the melting furnace and the glass melting tank,
There is no problem with using a single tank or three or more tanks.

On the other hand, when the stirring experiment was conducted according to the conventional glass melting furnace, the following results were obtained. That is, although not particularly shown in the drawing, this experimental device has the same structure as the device of the fourth embodiment (FIG. 6) except that the insertion tube 73 is cut out and the inner diameter of the opening 72 is reduced to 30 to 40 mm. , As it is.

As a result, the gap between the stirring rod 71 having an outer diameter of 20 mm and the opening 72 is 5 to 10 mm over the entire circumference.
Becomes the width of. In addition, in the comparative experiment, the molten glass, the charging conditions, and the stirring conditions were set to be the same as those in the fourth embodiment.

As a result of the comparative experiment, the temperature of the lower surface of the heat shield plate 77 is about 390 after the start of the experiment because the heat rising airflow from the inside of the furnace to the outside of the furnace is intense through the opening 72. .About.450.degree. C., and the temperature of the lower surface of the electric motor above it was about 120 to 140.degree. C., and the temperature continued to rise. Therefore, if the stirring drive system does not have a special cooling mechanism such as water cooling, further continuous stirring experiments cannot be performed.

The refractive index nd (5
The fluctuation amount of 87.56 nm) becomes large, ± 52 to 10
It reached 0 × 10 ^-5 . Further, it was also found that an opaque solid material called “devitrification” was projected inside the outflow pipe 78, the pipe inner diameter was narrowed, and the glass outflow amount deviated from a predetermined value. Further, the "devitrified substance" is sometimes mixed in the molten glass 79 flowing out, and in this case, the required quality for the optical element cannot be satisfied.
The cause of these is that the heat rising airflow from the inside of the furnace to the outside of the furnace is intense through the opening 72, and the components of the molten glass are selectively evaporated depending on the temperature, and the molten glass is placed on the heat rising airflow and goes out of the furnace. It is considered that the composition of the melted glass has changed. In addition, when the composition changes and the refractive index changes, there is a risk that qualities other than the refractive index, such as optical characteristics, thermal characteristics, and chemical characteristics, also change.

As described above, when the molten glass is stirred, the insertion tube is inserted into the opening for inserting the stirring rod, one end of the insertion tube is immersed in the molten glass, and the other end is immersed. Through the opening to shut off the inside and outside of the furnace and seal the atmosphere inside the furnace to avoid heat rising flow from inside the furnace to outside the furnace through the insertion tube. The system does not require a special cooling mechanism such as water cooling. Further, there is an effect of preventing quality variation and deterioration of glass.

The above-described first to first embodiments of the present invention will be described.
In using the pipes in the glass melting operation process such as the glass raw material feeding pipe, the liquid level measuring insertion pipe, and the stirring insertion pipe in 4 above, each of them may be used alone, or at any time. It goes without saying that a plurality of pipes can be arbitrarily combined. Therefore, by the communication means, the glass raw material charged into the glass melting tank is shielded from the atmosphere inside the furnace, there is no influence of the heat rising airflow, the scattering of the glass raw material outside the furnace can be prevented, and an accurate charging amount is realized. At the same time, the introduced glass raw material can solve the conventional problems of contaminating the clarified molten glass in the furnace or in the glass melting tank, and further prevent the quality variation of the glass.

Further, the glass raw material feeding pipe provided as the communication means can prevent the glass liquid surface from wavy when the raw material is fed. Further, by providing the glass raw material feeding pipe with a temperature adjusting means, it is easy to melt the glass raw material attached to the inner wall of the feeding pipe, and even if the feeding amount increases, the glass raw material does not melt, You can prevent it from getting stuck.

As described above, in the present invention, in carrying out the above-mentioned various operations required for glass melting, in order to improve the operation and facilitate heat countermeasures in the peripheral equipment of the melting furnace, The relationship with the atmosphere in the furnace can be improved.

[0115]

As described above, according to the present invention,
The following effects can be obtained.

1. When the furnace body is provided with an opening and various glass melting operations are carried out, for example, one end is soaked in the molten glass with a communicating means such as a pipe, and the other end is exposed to the outside at the opening. Since it is derived and the atmosphere inside the furnace is shut off from its operation area, a heat rising airflow from the atmosphere inside the furnace can be prevented, resulting in improved workability and no special cooling mechanism for the peripheral equipment of the melting furnace. .

2. Further, by heating the glass raw material feeding pipe in a temperature-adjustable manner, and further by directly and electrically heating the feeding pipe, the fed glass raw material adhered to the inner wall of the feeding pipe is easily melted, and the feeding amount is increased. However, it is possible to avoid the situation where the raw material does not melt and is clogged in the charging pipe, and it is possible to cope with the case where the glass pulling amount (= input amount = outflow amount) is relatively large.

3. As a result of preventing the rising heat flow from the atmosphere inside the furnace when charging the glass raw material, it is possible to prevent the raw material from scattering outside the furnace when the raw material is charged, and as a result, it is possible to achieve an accurate charging amount and It is possible to prevent contamination of the inside of the furnace and the molten glass by the glass raw material. Furthermore, when the raw materials are added,
Since the liquid surface of the molten glass can be prevented from waviness, the liquid surface level of the molten glass can be measured with high accuracy.

4. Prevents heat rising airflow from the furnace atmosphere when measuring the liquid level of the molten glass and stirring the molten glass, which prevents the glass from selectively evaporating and changing the glass composition. Therefore, it becomes possible to prevent the quality variation of the glass.

[0120]

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first embodiment of the present invention.

FIG. 2 is a flowchart of a temperature adjustment function.

FIG. 3 is an explanatory diagram of the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of a second embodiment of the present invention.

FIG. 5 is an explanatory diagram of a third embodiment of the present invention.

FIG. 6 is an explanatory diagram of a fourth embodiment of the present invention.

FIG. 7 is an explanatory diagram of a conventional example.

FIG. 8 is an explanatory diagram of another conventional example.

[Explanation of reference numerals] 1 glass melting furnace 2 melting and refining section 3 outflow section 4 partition wall 5 melting and refining tank 6 connection pipe 7 outflow tank 8 outflow pipe 10 molten glass 11 glass liquid surface 12 opening section 13 glass raw material input tube 14 flange section 15 Zhougo 16 Cup 17 Lid 18 Arm 19 Arm 20 Arm 21 Glass raw material 22 Raw material 23 Input raw material 23 Adhering to input pipe 24 Outflow glass 25 Glass raw material input pipe 26 Flange 27 Raw material flying outside the furnace 28 Raw material flying in the furnace 29 Raw Material Contaminated in the Furnace 30 Raw Material Contaminated in the Molten Glass 31 Wavy Liquid Level 32 Opening on the Side of the Furnace 33 Cup 34 Arm 35 Raw Material Flying in the Furnace 26 Raw Material Contaminated in the Furnace 37 Contaminated Molten Glass Raw material 38 Wavy liquid surface 39 Glass raw material 40 Direct current heating lead plate 41 Contact heating heating lead plate 42 Power source 43 Thermocouple 44 Temperature controller 45 Glass raw material feeding pipe 46 Opening 47 Glass raw material 48 Hopper 49 Charger 50 Glass raw material feeding pipe 51 Flange portion 52 Opening 53 Liquid level measuring insertion pipe 54 Flange part 55 Needle sensor 56 Axis 57 Clamp holder 58 Vertical drive shaft 59 Frame 60 Vertical drive device 61 Liquid level controller 62 Lead wire 63 Lead wire 64 Signal line 65 Power line 66 Control line 67 Melt clarification part 68 Connection pipe 69 Outflow Portion 70 Glass Raw Material Input Pipe 71 Stir Bar 72 Opening 73 Disturbance Inserting Tube 74 Molten Glass 75 Flange Part 76 Stirring Blade 77 Heat Shielding Plate 78 Glass Raw Material 79 Outflow Glass 80 Glass Raw Material 81 Thermocouple 82 Heater 83 Temperature controller 84 Power supply 85 Temperature Issue 86 Heater output signal 87 thermocouple 88 heater 89 temperature controller 90 power source 91 temperature signal 92 Heater output signal 93 directly energized heating lead plate 94 directly energized heating lead plate 95 thermocouple 96 temperature controller 97 Heating output signal 98 power

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayuki Tomita 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (16)

[Claims] 1. A molten glass raw material used for forming a glass processed product by flowing out from a glass melting furnace to an outside, and an opening for introducing the solid glass raw material in a solid state into the glass melting furnace. A furnace body having a portion, heating means for maintaining the inside of the furnace body at a predetermined set temperature for heating and melting the solid glass raw material, and the furnace for storing the molten glass raw material in a molten state by the heating means A glass melting tank disposed inside the main body, a liquid level of the molten glass raw material in the glass melting tank, and a communication means for separating between the opening from the liquid level, the solid A molten glass raw material obtained by charging a glass raw material into the glass melting tank through the communicating means. 2. A molten glass raw material used to form a glass processed product by flowing out from a glass melting furnace to the outside, wherein the solid glass raw material in a solid state is charged into the glass melting furnace. A furnace body having an opening that opens upwards in the interior, and is divided into a melting and refining section and an outflow section inside by a partition wall section; and the melting and refining section and the outflow section for heating and melting the solid glass raw material. And heating means for maintaining each at a predetermined set temperature, a glass melting tank arranged in the melting and refining section for storing the molten glass raw material in a molten state by the heating means, and the glass melting tank An outflow tank connected to the outflow portion and disposed in the outflow portion, an outflow pipe provided in the fluid tank, a liquid surface of the molten glass raw material in the glass melting tank,
Comprising a communication means for making a state of being isolated from the liquid surface between the opening portion, the solid glass raw material is charged into the glass melting tank through the communication means, and introduced into the outflow tank, A molten glass material obtained by flowing out to the outside through an outflow pipe. 3. A method for producing a molten glass raw material, which is used for forming a glass processed product by flowing out from a glass melting furnace to an outside, wherein the glass melting furnace is provided with a solid glass raw material in a solid state inside. A furnace body having an opening for charging, heating means for maintaining the inside of the furnace body at a predetermined set temperature for heating and melting the solid glass raw material, and for storing the molten glass raw material in a molten state by the heating means A glass melting tank disposed in the furnace body, a liquid surface of the molten glass raw material in the glass melting tank, and a communication means for separating the opening from the liquid surface. The method for producing a molten glass raw material, wherein the solid glass raw material is charged into the glass melting tank through the communicating means to obtain the molten glass raw material. 4. A method for producing a molten glass raw material, which is used for forming a glass processed product by flowing out from a glass melting furnace to an outside, wherein the glass melting furnace comprises a solid glass raw material in a solid state inside. While having an opening opening upward for charging, a furnace body divided into a melting and refining section and an outflow section inside by a partition wall, and the melting and refining section for heating and melting the solid glass raw material. Heating means for maintaining the outflow portion at each predetermined set temperature, a glass melting tank provided in the melting and refining portion for storing the molten glass raw material in a molten state by the heating means, the glass An outflow tank connected to the melting tank and arranged in the outflow portion, an outflow pipe provided in the fluid tank, and a liquid surface of the molten glass raw material in the glass melting tank.
Comprising a communication means for making a state of being isolated from the liquid surface between the opening portion, the solid glass raw material is charged into the glass melting tank through the communication means, and introduced into the outflow tank, A method for producing a molten glass raw material, characterized by being obtained by flowing out to the outside through an outflow pipe. 5. The communicating means is provided with the opening so that the solid glass raw material supplied through the opening is introduced only into a predetermined region of the liquid surface of the molten glass raw material in the glass melting tank. The molten glass raw material according to claim 4, characterized in that it has a flange portion communicating with the predetermined region, and a lid or a means for supplying solid glass raw material is appropriately provided in the flange portion. Production method. 6. The lid body thermally blocks the outside air of the opening from the molten glass raw material in the furnace body,
The method for producing a molten glass raw material according to claim 5, wherein an atmospheric temperature in the furnace body is maintained within a predetermined temperature range. 7. The lid body thermally disconnects the outside air of the opening from the molten glass raw material in the furnace body,
By thermally blocking the outside air of the opening from the molten glass raw material in the furnace body, by preventing the atmospheric temperature in the furnace body from being released to the outside of the furnace body, The method for producing a molten glass raw material according to claim 5, wherein the ambient temperature can be maintained below a predetermined temperature. 8. An apparatus for producing a molten glass raw material, which is used for forming a glass processed product by flowing out from a glass melting furnace to an outside, wherein the glass melting furnace comprises a solid glass raw material in a solid state inside. A furnace body having an opening for charging, heating means for maintaining the inside of the furnace body at a predetermined set temperature for heating and melting the solid glass raw material, and for storing the molten glass raw material in a molten state by the heating means A glass melting tank disposed in the furnace body, a liquid level of the molten glass raw material in the glass melting tank, and a communication means for separating the opening from the liquid level. An apparatus for producing a molten glass raw material, wherein the solid glass raw material is obtained by charging the solid glass raw material into the glass melting tank through the communicating means. 9. An apparatus for producing a molten glass raw material, which is used for forming a glass processed product by flowing out from a glass melting furnace to the outside, wherein the glass melting furnace comprises a solid glass raw material in a solid state inside. While having an opening opening upward for charging, a furnace body divided into a melting and refining section and an outflow section inside by a partition wall, and the melting and refining section for heating and melting the solid glass raw material. Heating means for maintaining the outflow portion at each predetermined set temperature, a glass melting tank provided in the melting and refining portion for storing the molten glass raw material in a molten state by the heating means, the glass An outflow tank connected to the melting tank and arranged in the outflow portion, an outflow pipe provided in the fluid tank, and a liquid surface of the molten glass raw material in the glass melting tank.
It comprises a communicating means for making a state of being isolated from the liquid surface between the opening portion, and the solid glass raw material is introduced into the glass melting tank through the communicating means and introduced into the outflow tank. An apparatus for producing a molten glass raw material, which is obtained by flowing out to the outside through the outflow pipe. 10. The communication means for shutting off the opening from the atmosphere in the furnace with one end led out to the outside through the opening and the other end immersed in the molten glass raw material. The apparatus for producing a molten glass raw material according to claim 9, wherein the apparatus comprises a glass raw material feeding pipe. 11. The apparatus for producing a molten glass raw material according to claim 10, wherein the glass raw material feeding pipe is equipped with temperature adjusting means including a temperature sensor and a heater. 12. The glass raw material feeding pipe is electrically conductive, and direct heating to the glass raw material feeding pipe is used for heating by a heater for adjusting the temperature of the glass raw material feeding pipe. 10. The apparatus for producing a molten glass raw material according to 10. 13. The glass raw material feeding pipe is made of gold, platinum,
12. A pipe made of a noble metal material such as rhodium, according to any one of claims 10 to 11.
An apparatus for producing a molten glass raw material according to item. 14. The apparatus for manufacturing a molten glass raw material according to claim 9, wherein the opening is configured to be shielded from the outside by opening and closing the lid. 15. In a glass melting furnace having an opening for introducing a glass raw material, and introducing the glass raw material into a glass melting tank arranged in the furnace through the opening, another opening communicating with the inside of the furnace is provided. An insertion tube for inserting a sensor for measuring the liquid level of the molten glass from the outside is provided with one end led out to the outside through this opening and the other end immersed in the molten glass. An apparatus for producing a molten glass raw material, which is characterized in that 16. A glass melting furnace having an opening for introducing a glass raw material, and introducing the glass raw material into a glass melting tank arranged in the furnace through the opening, another opening communicating with the inside of the furnace is provided. It is equipped with an insertion tube for inserting a stirring means for the molten glass from the outside in a state in which one end is led out to the outside through this opening and the other end is immersed in the molten glass. Equipment for manufacturing molten glass raw materials.