JPH0280327A - Treatment of molten glass - Google Patents

Abstract

PURPOSE:To improve the quality of a glass article by reducing the content of bubbles therein by utilizing numerous solid pieces having minute sizes in the treatment of molten glass by the bubbler method. CONSTITUTION:An ejecting port 3a of gas is provided to a top end of a bubbler tube 3 extending upwards in the molten glass 2 after penetrating decking tiles at the bottom of a glass melting tank. A mixture 5 of solid and gas contg. previously suspended fine glass pieces having a same compsn. as the glass 2 is fed to the bubbler tube 3 through a feeding pipe, and the mixture is ejected into the glass 2 through the ejecting port 3a. Thus, a gas foam 6 is formed at a tip end of the bubbler tube 3. Fine glass pieces 7 are supplied to the inside of the gas foam 6. The fine glass pieces are blown by the stream of the gas expressed by an arrow mark (a) to the top area of the inside of the gas foam 6, and melted by the heat supplied from the glass 2 and stick to the inside surface of the foam 6, forming thus many fine unevennesses 9 around the glass pieces 7 as nuclei on the inside surface of the foam 6. Such foams 6 grow increasingly, rise upward in the glass 2 after separating from the bubbler tube 3, and stir the glass 2. In this stage, the gas dissolved in the glass 2 is liberated by diffusion through the large surface area at the interface of the foams.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for processing molten glass in the field of glass manufacturing, where the quality of bubbles, cords, etc. of products is a problem.

[Conventional technology]

The glass melting and fining process has a long history.
High-temperature melting furnace 5 classical equipment and 1. Operations that handle this have become the core of this process technology.

In response to this, we introduced a device with mechanical forcing into this melting and cleaning process, and instead of relying solely on traditional thermal reactions and heat convection, we utilized modern mechanisms to achieve this goal. Recently, various attempts have been made to improve the efficiency of the process or the quality of the target product, and one of them is to forcibly eject gas from a fumarole into the molten glass in the glass melting tank. One example is a bubbler type, which generates air bubbles and performs bubbling by floating the air bubbles.

To briefly explain the purpose of the current bubbler system when it was developed and the effectiveness of the one currently in use, the first purpose was to generate a large number of bubbles generated from the numerous bubbler fumarole holes provided at the bottom of the melting tank. Utilizing the interface of the bubbles, the gas components melted in the molten glass are diffused not only from the free upper surface of the molten glass but also into these bubbles, ultimately improving the diffusion effect into the furnace atmosphere. It is also said that the purpose was to make him do so. However, in an industrial practical example, even if bubbles are generated from a large number of bubbler nozzles, the total surface area of the interface formed by the bubbles in the molten glass is the same as that of the free upper surface of the glass substrate. In contrast, the diffusion and release of dissolved gas components within the glass substrate through the bubbler bubble interface was extremely small, and almost no effect could be expected.

However, by increasing the stability of the vortex in this region of the melting tank due to the combination of the vortex caused by the heat convection of the glass substrate and the artificial vortex generated by the bubbler system described above, it is possible to maintain the quality of the product. It has been recognized that the current bubbler system has the effect of improving its stability, and the current bubbler system is expected to have a greater effect on striae (coat 9) due to local heterogeneity of the glass component, which is cited as a quality defect of the product. On the other hand, the above-mentioned artificial vortex generated by the bubbler system in this area generates active mixing and agitation in the glass base, which eliminates the striae.

In addition to this, as a mechanical means for eliminating striae, a stirrer system that rotates a stirrer in the substrate has also been widely put into practical use.

[Problems that the invention aims to solve]

In other words, in the conventional technology, both the buzz large system and the stir large system are practical and effective in terms of the five mechanisms of mixing and stirring molten glass, but they are not effective in dealing with foam, which is the most basic quality defect of glass products. , improvements based on clear mechanisms are out of reach.

Looking at the bubbles contained in molten glass, the larger diameter bubbles float up and disappear before the molding process, but the smaller diameter ones remain and are formed.
It turns out. At this time, r is small based on the physical law that the diameter is small (indeed, the osmotic pressure of the gas against the molten glass on the outer periphery increases, and the gas melts into the molten glass surrounding the microbubbles, making the bubble diameter even smaller. The place that disappears
■Ideally, cuddles are carried out, but in reality, bubbles may remain in the final product depending on the balance between the gas concentration in the microbubbles and the concentration of gas dissolved in the molten glass that surrounds them. become.

In order to reduce the residual rate of bubbles in the final product from the chemical balance regarding permeation and diffusion of the gas mentioned above, it is necessary to increase the saturation rate of the concentration of gas dissolved in the molten glass in the glass melting and refining process. It is fundamentally important to keep this low.

Considering the above-mentioned approach to improving foam quality in which gas components trapped in the molten glass are diffused and eliminated to reduce their concentration, the solution itself is to diffuse the dissolved gas in the liquid into the gas through the gas-liquid interface. Although it is difficult to find mechanical means to promote the efficiency of this diffusion itself, if we focus on the fact that this diffusion occurs through the gas-liquid interface as mentioned above, this diffusion can be improved. If the total surface area of the liquid interface can be greatly increased using a new mechanical method, the amount of gas dissolved in the molten glass will increase, even if the area and per-diffusion efficiency at the gas-liquid interface do not change. It becomes possible to greatly increase the amount of diffusion into bubbles, paving the way for mechanical methods to improve foam quality.

The problem to be solved here is to find and find solutions to five methods for forcibly dispersing a large number of microscopic bubbles into molten glass using a mechanical method. However, if you try to disperse a large number of microscopic bubbles in a liquid with high surface tension like molten glass using a simple mechanical method,
This requires enormous mechanical energy. Therefore, mechanical energy is only partially used, and thermal energy is mainly used as an energy source to generate microbubbles. Unless this is combined with a physical method, the level of practical improvement in pond quality cannot be achieved. It is difficult to obtain the size of the total surface area of the bubble interface.

That is, in consideration of the fact that it is difficult to create microscopic bubbles in molten glass, which is a viscous fluid, by mechanical force, in the present invention, countless microscopic solid pieces are used for bubbling in the bubbler process as described below. This is an attempt to solve the above problems.

[Means to solve the problem]

The present invention has the following features: (1) Air bubbles are generated in the molten glass by forcibly blowing gas into the molten glass from a blow tube inserted into the molten glass in the glass melting tank from the bottom of the tank. , a method for processing molten glass in which buzzing is performed by floating air bubbles, in which minute glass pieces having the same composition as the molten glass are suspended in advance in the gas ejected from the fumarole pipe, and the bubbles are released from the fumarole pipe. By the time the glass particles start floating in the molten glass, the glass particles collide and fuse with the inner surface of the bubble, forming a large number of fine uneven surfaces on the inner surface of the bubble.
did.

(2) In the method for treating molten glass, the gas is ejected from the fumarole tube almost horizontally, that is, horizontally, or slightly diagonally upward or diagonally downward with respect to the horizontal.

[For production]

In the present invention described in (1) above, bubbles are formed inside the molten glass at the end surface of the ejection port of the fumarole tube, and by the time the bubbles expand and grow and separate from the fumarole tube and start floating in the molten base, the gaseous At the same time, the glass particles ejected into this bubble collide with the inner surface of the bubble, receive heat from the molten glass and fuse to the inner surface, and many glass particles with these glass particles as cores are formed on the inner surface. A finely uneven surface is formed.

In this way, the bubbles, which have a large number of finely uneven surfaces on their inner surfaces, leave the fumarole pipe, rise in the molten glass, and burst after reaching the upper surface, so each bubble itself bursts and disappears. In addition, the finely uneven surface formed on the inner surface of a bubble, which is made up of many microscopic pieces of glass, undergoes a process in which when the bubble ruptures, the inner surfaces of the bubble fuse together to form a small bubble, which then ruptures again. After this process is repeated, microbubbles with the glass micropieces as their core are left dispersed on the upper surface of the molten glass.

As a result, compared to the total inner surface area of the floating bubbles in the conventional bubbler system, after the bubbles burst on the upper surface of the molten glass, a large number of microbubbles with a large total inner surface area are formed on the upper surface of the molten glass. is formed.

Through the wide interface of the many microbubbles formed in this way, the gas dissolved in the molten glass is effectively diffused and released into the microbubbles, and these artificially created microbubbles The upper surface of the glass in the clarification zone is heated and ultimately bursts, at which time the gas inside the microbubbles is released into the atmosphere of the melting tank.

In this way (-), in the present invention (1) above, the dissolved gas in the molten glass base heading for the product manufacturing process is transported through the large total surface area formed by the large number of microbubbles with the microscopic glass pieces as cores. The amount of dissolved gas in the molten glass matrix is reduced by effectively absorbing the dissolved gas into the microbubbles and dissipating the dissolved gas into the furnace atmosphere by bursting the ultimate microbubbles on the top surface of the glass. As a result, the foam quality of the product will be improved.

Moreover, the glass micropieces that served as the nucleus for the generation of the microbubbles go through the above steps and melt into the surrounding molten glass having the same components to form a glass base.

In the present invention described in (2) above, in addition to the present invention described in (1) above, the ejection direction of the gas used for bubbling is set almost horizontally, that is, horizontally, slightly diagonally above horizontally, or slightly above horizontally. By diagonally downward, the bubbles are formed in a substantially horizontal direction. Since the momentum vector of the ejected gas flow is horizontal or in a near-horizontal direction, even if the amount of gas ejected is increased, the ejected air flow will not melt as compared to the conventional method of ejecting bubbles in the vertical direction. By forming a gas flow path in the glass that passes through the upper surface K11, it is possible to suppress a phenomenon called so-called blow-through.

That is, even if the jetting flow velocity is increased considerably compared to the conventional vertically upward jetting method, bubbling continues without causing blow-by.

Practical examples of bubbling systems applied to liquid tanks are currently widespread, not only in glass melting tanks, but what is required in this case is that the entire gas flow at the end of the spout is Pressure=static pressure+dynamic pressure exceeds the liquid pressure of the liquid tank applied to the end face of the jet nozzle.

According to the present invention (1) above, the specific gravity of the ejected flow is greater than that in the case of gas alone, and in addition to this, the present invention (2) above makes it possible to increase the ejected flow velocity. In the composition of the total pressure of the jet flow, in the conventional bubble separation method using buoyancy, the static pressure component accounted for most of it, but now it is possible to make the dynamic pressure component the main component of the total pressure. Become.

That is, in the present invention described in (2) above, it is possible to continue bubbling by reducing the diameter of this gas jet, and the hydrostatic pressure of the molten glass applied from the outside to the flow path of this small diameter jet causes this gas jet to are divided to form small-diameter bubbles.

Therefore, in the present invention described in (2) above, in addition to the effect of the present invention described in (1) above, the upper limit of the amount of ejected gas for bubbling is increased and the diameter of the generated and floating bubbles is decreased, thereby improving the bubbling effect. It will be increased.

Furthermore, since the ejected gas for the bubbler in the present invention described in (2) above contains minute glass particles, its apparent specific gravity and therefore its inertia as a fluid are large. In contrast to the rising buoyant force component of the bubbles that connects the gas to the atrium, this inertial force, mainly in the horizontal direction, which is unrelated to the upward vector, maintains bubbling without reaching the upper limit of the gas ejection volume of the atrium. The upper limit becomes even larger.

〔Example〕

A first embodiment of the present invention will be explained with reference to FIGS. 1 to 3.

As shown in FIG. 1, air, He, 02. is equipped with a flow meter 6 and a pressure gauge. The supply pipe U of gas such as H2O is connected to a plurality of ceramic bubbler pipes 3 as fumarole pipes provided in the degassing vortex region between the melting zone and the clarification zone of the glass melting tank. The gas supply pipe is connected to a small glass piece supply pipe 21 having a rotary feeder containing glass minute pieces 7 having the same composition as the glass in the melting tank.

As shown in FIG. 2, each of the bubbler tubes 3 extends upward into the molten glass 2 through the bottom tile 1 of the melting tank, and is provided with a spout 3a at its upper end. Around each of the bubbler tubes 3, there is provided a double water-cooled jacket tube 4 which penetrates the furnace bottom tile 1 of the melting tank and circulates cooling water.

In this embodiment, gas and minute glass pieces are led to the bubbler tube 3 through the supply pipe U, and the solid-gas mixed gas 5 in which the minute glass pieces are suspended passes through the outlet 3a of the bubbler tube and enters the melting tank. into the molten glass, and bubbles 6 are formed at the tip of the bubbler tube 3.
is formed. Micro glass pieces 7 are supplied into the bubble 6 together with the gas as described above, and are mainly blown onto the upper part of the inner surface of the bubble 6 by the gas flow shown by the arrow a in FIG. The minute glass pieces 7 receive heat from the molten glass and are fused to the inner surface of the bubble 6, thereby forming a large number of fine uneven surfaces 9 having the minute glass pieces as cores on the inner surface.

In this way, the bubble 6, which has a large number of finely uneven surfaces on its inner surface, gradually becomes larger as it is supplied with gas from the bubbler tube 3, and the bubbler tube 3 also separates and rises inside the molten glass 2. An upward flow of the molten glass itself is induced in the molten glass 2, and this serves as a driving source to generate a vortex in the molten glass 2 and stir the molten glass.

As shown in FIG. A large number of microbubbles with the microscopic glass pieces 7 as cores are formed on the upper surface of the glass substrate 2 .

The gas dissolved in the molten glass 2 is diffused and released into the large number of microbubbles thus formed through the interfaces having a large surface area. These fine /Jλ bubbles are heated on the upper surface of the glass in the melting surface area and ultimately burst, at which time the gas within the fine bubbles is released into the atmosphere in the upper space of the melting tank.

The minute glass pieces 7 having the same composition as the molten glass are melted by receiving heat from the molten glass, and are mixed and absorbed into the molten glass 2.

The sum of the inner surface areas of the large number of microbubbles formed with the microscopic glass pieces 7 as cores is much larger than the inner surface area of the bubbles formed only by gas, and in addition, the floating Since the diameter of the bubble is significantly smaller than that of the bubble to be burst, it takes time for the bubble to be heated on the upper surface of the glass and burst.

That is, the molten glass 2 on the inner surface of the microbubbles is formed on the free upper surface of the glass in the clarified melt region and then disappears.
The total area involved in the diffusion and release of spider gas over time is large, and through this large diffusion and release interface, the gas in the molten glass is effectively absorbed into the microbubbles, and the dissolved gas in the molten glass 2 concentration can be reduced, resulting in improved foam quality of the product.

Here, the size of the total area of the inner surfaces of the microbubbles in this example will be explained.

/ζ Average amount of gas ejected per puller is VNtr? /
mTA+ If the number of bubbler tubes is n, then the bubbler gas amount V = v n Nm''/rhyme.

In this example, V=V :95, and the microscopic glass pieces are actually crushed glass powder, but
For calculation purposes, K is assumed to be a regular cube, and the average value of its -side lengths is defined as μ.

Under this condition, the surface area 51fn3/M of the minute glass pieces 7 ejected into the molten glass 2 per minute is = 600.
It becomes tX.

Another estimate is that the space ratio of the volume of the filler itself and the void formed between the filler in a layer filled with tiny regular cubic glass pieces as a filler is 60:40, and this void space is, for example, 20μ. If it is divided into true spheres with a diameter of ×±, the total surface area of the fine spheres formed in 1 minute is 52fi''
teeth.

becomes.

Referring to the above estimation, in this example, the microbubbles formed on the free upper surface of the molten glass were generated on the free upper surface.
If these microbubbles are maintained for a few minutes and then disappear, the total surface area of the bubbles continuously formed over time will be on the order of 600 to 700 m', which is within the melting and fining range of industrial glass furnaces. 10 of the area of the free upper surface
It is possible to maintain the diffusion and release interface of the gas dissolved in the molten glass more than twice as much.

A second embodiment of the present invention will be explained with reference to FIGS. 4 and 5.

The ceramic Z-pull tube 3 of this embodiment is arranged as shown in FIG.
However, an injection pipe 3b extending horizontally is provided at the upper end of the bubbler pipe 3, and the injection pipe 3b
The tip is opened in the outer wall of the double water-cooled mantle tube 4 to form a spout 3a.
is formed.

In this embodiment, the gas in which minute glass pieces are suspended is ejected horizontally from the ejection port 3a, and closed cells 6 are formed in the molten glass 2, which are arranged substantially horizontally. Inside the bubble 6, the gas flow flowing in the direction of the arrow blows microscopic pieces of glass mainly at the tip of the bubble, which receives heat from the molten glass and fuses to the inner surface of the bubble 6, forming the first As in the embodiment, a large number of uneven surfaces with micro glass particles as cores are formed on the inner surface.

Therefore, in this embodiment, as in the first embodiment, when the bubbles 6 leave the spout 3a of the bubbling tube 3 and rise to the surface, the molten glass 2 around the bubbles 6 is induced to rise accordingly. When the molten glass 2 is stirred using the flow as a driving source, and when the bubbles 6 reach the upper surface of the molten glass 2 and burst, a large number of microbubbles with microscopic glass pieces 7 as nuclei are formed. Since the diameter of the bubbles is minute, the gas dissolved in the molten glass is absorbed into the bubbles through the large internal area of the minute bubbles within the time required for the bubbles to burst again.

In addition, in this embodiment, since the gas is ejected in the horizontal direction as described above, the bubbles 6 are formed in the horizontal direction, and the momentum vector of the ejected gas flow in which the glass particles 7 are suspended. has a horizontal direction, the bubbles 6 are formed in the horizontal direction. For this reason, even if the amount of gas ejected per hour is increased, the mixing ratio of the glass particles 7 suspended in the ejected gas to the gas may be increased (thus increasing the apparent specific gravity of the ejected flow). However, as long as the diameter of the ejection port at the end of the ejection tube is kept at an appropriately small diameter, the greater the momentum of the ejected gas flow, the more the ejected airflow can penetrate the inside of the molten glass 2 even if the bubbles are torn apart in the horizontal direction. It does not blow through toward the upper surface.In addition, the gas jet is divided by the hydrostatic pressure of the molten glass applied to the flow path of this gas jet, and bubbles with a small diameter are formed.Therefore, the bubbling caused by the bubbles 6 is It can be done effectively.

A third embodiment of the present invention will be explained with reference to FIG.

This embodiment differs from the second embodiment in that the bubbler tube 3
The structure near the ejection port has been changed as follows.

That is, the bubbler tube 3 is made of ceramics, a spout having a horizontal axis is disposed at the upper end thereof, and the inner tube 4a of the double water-cooled outer tube 4 is disposed close to the outer periphery of the bubbler tube 3. By arranging the intermediate pipe 4c between the outer pipe 4b and the inner pipe 4a of the mantle pipe 4, a rising passage for cooling water is formed between the above-mentioned pipes 4a and 4c, and between the above-mentioned pipes 4c + 4b. A double water-cooled jacket tube 4 is formed with a downward passage for cooling water. Further, a spout 3a is provided in the upper end of the ceramic bummerer tube 3 in the horizontal direction, and the spout 3a K
A truncated cone-shaped gas ejection passage 4d#'' is provided, which opens at a corresponding position in the inner pipe 4aK and expands outward in a trumpet shape, extending horizontally and opening into the outer pipe 4c.

In this embodiment, it is possible to suppress the wear due to the glass particles 7 at the jet nozzle portion in the second embodiment.
The operation of this embodiment is essentially the same as that of the second embodiment.

Here, the total planar shape and size of the inner surfaces of the microbubbles in the second and third embodiments will be explained below.

First, we will discuss the relative differences based on the rough estimate of the first embodiment.

First, V = 0.04 Nm7- was increased by V = 0.04x5 = 0.2 N27m1x K in the second and third embodiments.

The volume ratio of 5:95 between the glass particles 7 suspended in the buzzer gas and the gas is maintained in the same manner in the second and third embodiments.

Even if the flow rate of the jet flow and therefore the momentum of the jet flow were increased in this way, since the jet direction was horizontal, the floating bubbles were divided into small pieces and there was no problem with continuing bubbling. ) The second and third y! ,
In the example, stable continuation of the active forced vortex flow by this bubbler system was observed in the glass melting tank.

If the calculation criterion for Sl and S2 in the first embodiment is set to E, then in the second and third embodiments, Sl "" 3
000 tyz, S2''' 3600-, and if the microbubbles formed on the free upper surface of the glass in the melt-fining region are maintained on the same free surface for 1 minute after generation and then disappear, then the microbubbles are The total inner surface area of bubbles that are continuously formed over time under the conditions of the second and third embodiments is 300.
It will be on the order of 0 to 3600-.

Furthermore, in the second and third embodiments, the amount of gas ejected from the bubbler is larger than that in the first embodiment, which is close to the conventional method, and the volume of the floating bubbles per hour is increased. The local updraft in this region of the area is strengthened. In addition, in the conventional method or the first embodiment, the bubbles are separated from the bubbler tube 3 in balance with the static buoyancy of the bubbles. In the third embodiment, as described above, the inertial force of the jet of solid gas having a large apparent specific gravity promotes the separation of bubbles from the bubbler tube 3.

That is, the dynamic pressure of the ejected flow determines the strength of the vortex generated within the molten glass 2.

As a result, the stirring, mixing, and homogenization of the glass base by the vortex in the molten glass 2 formed by the bubbler, which has been the objective of the conventional nozzle puller system, can be carried out more actively.

Furthermore, as mentioned in 5 above, the fact that a significantly stronger upward flow occurs in one part of the bubbler than in the conventional one-bubbler type means that the bubbles generated near the spout of the bubbler pipe 3 or there begin to rise. Looking at the flow of the molten glass 2 near the part, in the conventional method, an underflow supplements the upward flow of the molten glass from the rear and front along the tiles toward the jet opening of the bubbler installed at the bottom of the melting tank. supplied,
Although the flow no.ζ lance was maintained, in the second and third embodiments, the bottom flow from the front and rear along the paving tiles alone was not enough to combine with the upward flow due to the forced gripping force of the bubbling. 72 In the front and rear regions of the free upper surface of the glass where the lance cannot hold it anymore and the bubbles burst, the molten glass containing microbubbles with the glass particles 7 as their cores formed there descends toward the bottom of the furnace. It was observed that airflow was formed.

As mentioned above, this is effective in improving the mixing and stirring function of the molten glass in this region, and 1. In any case of the first to third embodiments, the glass micropieces The explanation has been given on the assumption that the microbubbles with the nucleus 7 are floating on the free upper surface of the glass, but in the second and third examples, it is further assumed that the microbubbles floating on the upper surface are ,
A flow pattern is formed in which the molten glass 2 is constantly rolled up by the above-mentioned strong portex. This increases the time it takes for the microbubbles to disappear from their generation, and furthermore, the microbubbles are not only floating on the upper surface of the molten glass, but some or most of them are riding on the portex. Through the interface, these microbubbles circulate and convect in a widely dispersed manner inside the molten glass 2 for the purpose of diffusion and degassing of the gas contained therein.

This is not only due to the large area of 3,000 to 3,600 m'' of the microbubbles, but also to more efficiently diffuse and release the dissolved gas from the molten glass 2.

The gases used in each of the above examples are as follows:
Air, which has been conventionally used for bubbling, may be used, but 02 in air dissolves easily in glass, but N
2 is the gas used in the method of neutralizing the molten glass, which is formed with the bubble components in the glass product, and dissipating the dissolved gas into the atmosphere in the upper temperature furnace, which is diffused and released into the microbubbles. He, which easily dissolves in glass, N20,
It is better to use 02 etc.

〔Effect of the invention〕

As explained above, the present invention as set forth in claim 1 is characterized in that a gas in which microscopic glass pieces having the same composition as the molten glass are suspended is ejected from a blow tube into the molten glass, and the microscopic glass pieces are attached to the inner surface of the bubble. By forming a large number of finely uneven surfaces with the bubbles as a nucleus and performing bubbling with the bubbles, the bubbles reach the upper surface of the molten glass and a large number of microbubbles are formed with the same microscopic glass pieces as the nucleus. By utilizing the large inner surface, the gas dissolved in the molten glass can be diffused and released into these microbubbles, reducing the concentration of dissolved gas in the molten glass and improving the foam quality of the product. .

Further, the present invention according to claim 2 is the invention according to claim 1, in which the gas in which minute glass pieces are suspended is moved in a substantially horizontal direction Kl! By ejecting from the Jt trachea, even if the amount of ejected gas and the momentum of the ejected flow containing minute glass fragments are increased, the ejected flow will not blow through to the upper surface of the molten glass (on the contrary, the generated air bubbles will not blow through). It is possible to increase the amount of bubble gas or the amount of glass particles injected into the bubbles while reducing the diameter.

As a result, in terms of promoting the homogenization of the glass substrate by stirring and mixing the glass substrate in the conventional bubbler system, not only can a much higher stirring effect be obtained compared to the conventional method, but also the S puller according to the present invention In the melt clearing region that exerts its function, a large area of the inner surface of the microbubbles is maintained in a spatially dispersed form in the molten glass, so that the gas dissolved in the molten glass is The gas concentration of the molten glass that is diffused into microbubbles and processed into products is reduced, and the foam quality of the product is improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the entire apparatus used in the first embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional view of the vicinity of the upper end of the bubbling tube in the above-mentioned apparatus, and FIG. 3 is a diagram illustrating the apparatus in the first embodiment. An explanatory diagram of floating bubbles, FIG. 4 is a vertical cross-sectional view of the main part of the device used in the second embodiment of the present invention, and FIG. 5 shows the movement and floating of bubbles in the second embodiment. The explanatory drawing, FIG. 6, is a longitudinal sectional view of the main part of the apparatus used in the third embodiment of the present invention. 1... Melting tank bottom tile, 2... Molten glass. 3... Bubbler tube, 3a... Spout. 5...Solid-gas mixture in which minute glass pieces are suspended. 6...Bubble, 9...Fine uneven surface on the inner surface of the bubble. 10...Free upper surface of molten glass. Agent: Patent Attorney Akigai Sakama, 2 persons, Figure 1, Figure 4, Figure 5, Procedure Supplement (self-motivated), November 1988.

Claims (2)

[Claims] (1) Gas is forcibly ejected into the molten glass from the bottom of the glass melting tank through a blow tube inserted into the molten glass in the glass melting tank, thereby generating air bubbles in the molten glass. In a method for processing molten glass that involves bubbling by flotation, microscopic glass pieces having the same composition as the molten glass are suspended in advance in the gas ejected from the fumarole, and the bubbles are released from the fumarole and into the molten glass. A method for treating molten glass, characterized in that the glass particles collide and fuse with the inner surface of the bubble to form a large number of fine uneven surfaces on the inner surface of the bubble before the glass starts floating. (2) The method for treating molten glass according to claim 1, characterized in that the gas is ejected substantially horizontally from the fumarole pipe.