JP2003160340A - Vacuum deaerator - Google Patents

Abstract

(57) [Summary] [Problem] The present invention suppresses oozing from a joint between furnace materials that are in direct contact with molten glass, prevents erosion of a backup refractory or a heat insulating refractory of the molten glass, and Provided is a vacuum degassing apparatus for molten glass that can achieve a long life. In the ascending pipe 16 and the descending pipe 18 where the liquid pressure of the molten glass G is high, the present invention forms a plurality of divided chambers 13A, 13B... By increasing the pressures of 13A, 13B,..., The difference from the liquid pressure of the molten glass G is reduced, and the force that the molten glass G seeps into the decompression housing from the flow path of the ascending pipe 16 and descending pipe 18 is suppressed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vacuum degassing apparatus for molten glass, which removes bubbles from a continuously supplied molten glass.

[0002]

2. Description of the Related Art Conventionally, in order to improve the quality of molded glass products, a vacuum degassing apparatus for removing bubbles generated in the molten glass before molding the molten glass melted in a melting furnace by a molding apparatus. Is proposed.

The vacuum degassing apparatus 110 shown in FIG. 3 is used for a process of degassing the molten glass G in the melting tank 120 and continuously supplying it to the next processing tank. A defoaming tank 114 and a rising pipe 116 vertically attached downward at both ends of the decompression defoaming tank 114.
The decompression degassing tank 114, the ascending pipe 116, and the descending pipe 118 are provided in the decompression housing 112 whose interior is decompressed by vacuum suction.

The lower end of the ascending pipe 116 is immersed in the molten glass G in the upstream pit 122 communicating with the melting tank 120, and the lower end of the downcomer pipe 118 is similarly the next processing tank (not shown). Is immersed in the molten glass G in the downstream pit 124 communicating with the.

The vacuum defoaming tank 114 is provided generally horizontally within the vacuum housing 112 whose interior is decompressed by vacuum suction from a suction port 112C by a vacuum pump (not shown). Suction ports 114A and 114 communicating with each other
The inside of the vacuum degassing tank 114 is 1/3 to 1/20 through B.
The pressure is reduced to (atmospheric pressure).

As a result, the molten glass G in the upstream pit 122, which has not been subjected to the defoaming process, is sucked up and introduced into the decompression defoaming tank 114 through the rising pipe 116 by the siphon principle. Then, after the vacuum defoaming process is performed in the vacuum degassing tank 114, it descends through the downcomer 118 and is led to the downstream pit 124.

The decompression housing 112 is a casing made of metal, such as stainless steel or heat-resistant steel. Further, in the vacuum degassing tank 114, an upper space 114S is formed above the molten glass G filled to a predetermined height.
A heat insulating material 130 such as a refractory brick that heat-insulates the vacuum degassing tank 114, the rising pipe 116, and the descending pipe 118 inside the depressurizing housing 112 is disposed around them.

The vacuum degassing apparatus 110 is configured to process the molten glass G at a high temperature, for example, a temperature of 1200 to 1400 ° C., the vacuum degassing tank 114 and the rising pipe 1.
The flow path of the molten glass such as 16 and the downcomer 118 that is in direct contact with the molten glass G may be made of a noble metal tube such as platinum or a platinum alloy such as platinum rhodium.

[0009]

However, since the known vacuum degassing apparatus 110 uses an expensive noble metal such as platinum or a platinum-rhodium alloy, the apparatus becomes large in size and the flow rate increases, and the wall thickness of the pipe increases. I have no choice but to reduce the pressure,
There is a drawback that the tube breaks and molten glass easily leaks into the vacuum housing 112.

On the other hand, the flow path of the molten glass G that is in direct contact with the molten glass G may be made of a furnace material. However, even if the furnace material used is a denser furnace material, the molten glass G seeps out from the gaps in the joints, and the backup furnace material and the heat insulating material on the rear side of the dense furnace material are melted out and eroded to form the molten glass. There is a problem that the furnace material component dissolved in G deteriorates product quality. Further, particularly in the vacuum degassing apparatus 110, since the depressurized housing 112 is depressurized, the exudation of the molten glass becomes more remarkable, and the life of the vacuum degassing apparatus 110 itself is eroded by the erosion of the backup furnace material and the heat insulating material on the rear side. There is also the problem of shortening.

An object of the present invention is to solve the above problems, and prevents or suppresses exudation from the joint between the furnace materials that are in direct contact with the molten glass, and a backup refractory material for the molten glass or It is an object of the present invention to provide a vacuum degassing apparatus for molten glass capable of preventing corrosion of a heat insulating refractory, maintaining the pressure inside the vacuum housing, and extending the life.

[0012]

In order to achieve the above-mentioned object, the present invention provides a decompression housing which is vacuum-sucked to decompress the inside, and a decompression for decompressing molten glass provided in the decompression housing. A defoaming tank, a rising pipe provided in communication with the reduced pressure defoaming tank for sucking up and introducing molten glass before the reduced pressure defoaming into the reduced pressure defoaming tank, and provided in communication with the reduced pressure defoaming tank And a descending pipe for descending and extracting the molten glass after decompression degassing from the decompression degassing tank, wherein at least one of the accommodating part of the ascending pipe and the accommodating part of the descending pipe in the decompression housing The accommodating portion is horizontally divided into a plurality of stages, and a plurality of division chambers are vertically arranged side by side. Each of the divided division chambers has a pressure adjusting means capable of independently adjusting the pressure of each division chamber. It is characterized by being provided.

The present invention comprises a vacuum degassing tank, an ascending pipe, a descending pipe,
And a decompression housing, and the decompression housing has a structure in which the main body is divided at at least one place, and the pressure can be independently changed in each of the divided chambers, so that molten glass exudes. To solve the above problems.

Particularly, in the ascending pipe and the descending pipe, as described in claim 1, the decompression housing is horizontally divided into a plurality of stages to vertically arrange a plurality of division chambers, and the pressure of the division chambers is increased. By reducing the degree of pressure reduction, the difference between the pressure in each division chamber and the liquid pressure of the molten glass in the division chamber is reduced,
It is preferable to suppress the force of the molten glass exuding into the decompression housing from the flow paths of the rising pipe and the falling pipe.

Further, the liquid pressure of the molten glass in the ascending pipe and the descending pipe becomes lower from the lower position toward the upper position. Therefore, in order to reduce the pressure difference at an arbitrary position, as described in claim 2, the pressure of the plurality of divided chambers is increased by the pressure adjusting means so as to increase from the upper chamber toward the lower chamber. Control. As a result, the pressure difference can be suppressed to be small, and thus the exuding force of the molten glass can be further suppressed.

In order to maintain the siphon principle, when the minimum value of the liquid pressure of the molten glass in each divided chamber is GPi and the pressure in the divided chamber is HPi, the pressure is 0.5. It is preferable that the pressure adjusting means controls the pressure so that (atmospheric pressure) ≧ GPi−HPi ≧ 0 (atmospheric pressure).

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The vacuum degassing apparatus for molten glass of the present invention will be described below in detail with reference to the preferred embodiments shown in the accompanying drawings.

A vacuum degassing apparatus 10 for molten glass according to the embodiment shown in FIG. 1 is a generally gate-shaped vacuum housing 12 made of stainless steel, and a vacuum degassing tank having a rectangular cross section that is horizontally accommodated in the vacuum housing 12. 11 and an ascending pipe 16 and a descending pipe 18 which are vertically housed in the decompression housing 12 and have upper and lower ends attached to the left and right ends of the decompression degassing tank 11, respectively.

The vacuum degassing apparatus 10 carries out vacuum degassing processing of the molten glass G in the melting tank 20, and the next processing tank (not shown),
For example, it is used in a process for continuously supplying a plate material forming treatment tank such as a float bath or a forming operation tank such as a bottle.

The lower end of the ascending pipe 16 is immersed in the molten glass G of the upstream pit 22 communicating with the melting tank 20, and the lower end of the descending pipe 18 is the downstream pit 24 communicating with the next processing tank. It is immersed in the molten glass G.

The decompression defoaming tank 11 is decompressed through the suction ports 11A and 11B communicating with the decompression housing 12, together with the decompression housing 12 whose interior is decompressed by vacuum suction from the suction port 12C by a vacuum pump (not shown). The inside of the defoaming tank 11 is depressurized to a predetermined pressure.

As a result, the molten glass G in the upstream pit 22 before the defoaming process is sucked up by the siphon principle through the ascending pipe 16 and introduced into the depressurized defoaming tank 11. Then, after the vacuum defoaming process is performed in the vacuum degassing tank 11, it descends via the downcomer pipe 18 to move to the downstream pit 24.
Be derived to.

The decompression housing 12 is formed in a substantially gate shape and functions as a casing (pressure container) for ensuring airtightness when decompressing the decompression degassing tank 11, and in the embodiment, 5 Divided into two parts, vacuum degassing tank 11,
The ascending pipe 16 and the descending pipe 18 are configured so as to wrap around them. The number of divisions of the decompression housing 12 is five.
It is not limited to one.

For the vacuum degassing tank 11, the ascending pipe 16 and the descending pipe 18 of the present invention, it is preferable to use a dense electroformed refractory material. That is, a large capacity of the vacuum degassing apparatus 10 is realized by assembling a main part of the vacuum degassing apparatus 10 that is in direct contact with molten glass by assembling a brick made of an electroformed refractory material that is a dense electrocast refractory material. At the same time, the vacuum degassing process at a higher temperature can be performed.

The electroformed refractory brick is not particularly limited as long as it is obtained by electrically melting a refractory raw material and then cast into a predetermined shape, and various known electroformed refractory bricks can be used. Good. Among them, the corrosion resistance is high, alumina foam terms is small from the matrix (Al ₂ O ₃₎ based electroforming refractory bricks, zirconia (ZrO ₂₎ based electroforming refractory bricks, alumina - zirconia - silica (Al ₂ O ₃ -Zr
O ₂ —SiO ₂ ) -based electroformed refractory bricks and the like are preferably exemplified. Specifically, when the temperature of the molten glass G is 1300 ° C. or lower, it is Marsnite (MB), and when it is 1300 ° C. or higher. It is preferable to use ZB-X950, zirconite (ZB) (all manufactured by Asahi Glass Co., Ltd.) or the like.

Although a dense electroformed refractory material is used in the present embodiment, it is not limited to the dense electroformed refractory material, and a dense fired refractory material may be used.

The dense fired refractory bricks used as the dense fired refractory bricks include dense alumina refractory bricks, dense zirconia-silica refractory bricks, and dense alumina-zirconia-silica refractory bricks. It is preferable that at least one kind of refractory bricks is a dense fired refractory brick.

Further, inside the decompression housing 12, the high heat of the molten glass G is shut off in the region outside the decompression defoaming tank 11, the rising pipe 16 and the descending pipe 18, and the vacuum suction inside the decompression defoaming tank 11 is performed. It also includes a heat insulating material 30 made of refractory brick having a high porosity that does not hinder.

The decompression housing 12 is not particularly limited in material and structure as long as it has the airtightness and strength required for the decompression defoaming tank 11, but the outer surface side is not limited. Is preferably made of metal, particularly stainless steel or heat-resistant steel.

The decompression housing 12 has five divided chambers 13A, 13B, 13C and 13 as shown in FIG.
It is divided into D and 13E. These division chambers 13A-
Of the 13E, the divided chambers 13A and 13B are chambers for accommodating the ascending pipe 16 and are different from the conventional one chamber.
It is divided in the horizontal direction and arranged vertically in two stages. The division chambers 13A to 13E are adapted to be sealed by walls, and the division chambers 13A and 13B are provided with suction ports 14A and 14B, respectively.
A and 14B are provided with pressure adjusting devices (pressure adjusting means) 15A and 15B capable of independently adjusting the pressures in the divided chambers 13A and 13B, and including, for example, a vacuum pump and a regulator. It should be noted that the number of divisions of the decompression housing 12 in the ascending pipe storage portion is not limited to two.

The division chamber 13C is a chamber for accommodating the vacuum degassing tank 11, and a vacuum pump (not shown) is connected to the suction port 12C.

The division chambers 13D and 13E are chambers for accommodating the downcomers 18, and are one chambers that have been conventionally formed and are horizontally divided into two stages vertically. A suction port 14 is provided in each of the division chambers 13D and 13E.
D and 14E are formed, and the suction ports 14D and 14E are provided with pressure adjusting devices (pressure adjusting means) 15D and 15E that are capable of adjusting the pressure inside the division chambers 13D and 13E, and include, for example, a vacuum pump and a regulator. ing. The number of divisions of the decompression housing 12 in the downcomer housing is not limited to two. Further, in the embodiment, the decompression housings of both the ascending pipe housing portion and the descending pipe housing portion are divided, but at least one decompression housing may be divided.

These divided chambers 13A to 13E are respectively vacuum-sucked by a vacuum pump, and divided chambers 13A to 13E.
The inside is decompressed and HP1, HP2, HP3, H respectively
The pressure is set to P4 and HP5. The pressure HP3 in the vacuum degassing tank 11 arranged in the central portion is set to a pressure necessary to remove bubbles from the molten glass, for example, 1/20 to 1/3 (atmospheric pressure).

By the way, the liquid pressure of the molten glass in the ascending pipe 16 and the descending pipe 18 of the vacuum degassing apparatus 10 becomes lower from the lower position to the upper position by the principle of siphon. Therefore, in order to reduce the pressure difference between the division chamber and the molten glass existing in the division chamber at any position of the ascending pipe 16 and the descending pipe 18, the division chamber 13
The pressure adjusting device 15 increases the pressure of A, 13B, 13D, 13E from the upper chamber toward the lower chamber.
It is preferable to control by A, 15B, 15D and 15E.

An example thereof will be described. For example, the ascending pipe 16 and the descending pipe 18 corresponding to the division chambers 13A and 13E.
The minimum values GP1 and GP5 of the liquid pressure of the molten glass in the inside are 0.
8 (atmospheric pressure), ascending pipe 1 corresponding to division chambers 13B and 13D
6 and the minimum value GP2 of the liquid pressure of the molten glass in the downcomer 18.
And GP4 is 0.4 (atmospheric pressure), and the vacuum degassing tank 11
The minimum liquid pressure GP3 of the molten glass inside is 0.1 (atmospheric pressure)
If the pressure is H, the pressure H in the division chambers 13A and 13E
P1 is 0.5 (atmospheric pressure), the pressure H in the division chambers 13B and 13D
Set P2 to 0.2 (atmospheric pressure).

Accordingly, the difference between the pressure in the division chamber and the minimum value of the liquid pressure of the molten glass in the division chamber is set to P, and the division chamber 13
If P in A and 13E is P1, P1 = 0.8
-0.5 = 0.3 (atmospheric pressure).

On the other hand, in the conventional vacuum degassing apparatus 110 (see FIG. 3) having no division chamber, the pressure difference P is set to P.
Assuming 1 ′, P1 ′ = 0.8−0.1 = 0.7 (atmospheric pressure).

Therefore, the vacuum degassing apparatus 1 of the embodiment is
0 is capable of suppressing the pressure difference P1 between the division chambers 13A and 13E from 0.7 (atmospheric pressure) to 0.3 (atmospheric pressure), so that the molten glass G is divided from the flow paths of the ascending pipe 16 and the descending pipe 18. The force that exudes into the chambers 13A and 13E can be suppressed.

Therefore, it is possible to provide the vacuum degassing apparatus 10 for molten glass which has sufficient durability against the high temperature molten glass G and is excellent in safety.

The division chamber 13 with respect to the division chamber 13C
The differential pressure P2 between B and 13D is P2 = 0.4-0.2 = 0.
2 (atmospheric pressure), whereas in the conventional vacuum degassing apparatus, P2 ′ = 0.4−0.1 = 0.3 (atmospheric pressure). Therefore, in this case as well, the molten glass G It is possible to suppress the force that exudes into the division chambers 13B and 13D from the flow paths of the ascending pipe 16 and the descending pipe 18.

On the other hand, when the minimum liquid pressure of the molten glass in a specific division chamber is GPi and the pressure in the division chamber is HPi,
When GPi-HPi is 0, the molten glass G and the inner pressure of the housing are balanced, so that the glass flow is unlikely to occur. Further, when GPi-HPi becomes negative, the molten glass G is at a lower pressure than the housing, so that the problem that foreign matter containing brick foreign matter comes out into the glass easily occurs. Therefore, GPi-HPi is preferably 0 or positive, and is preferably 0.5 (atmospheric pressure) or less and 0.3 or less in order to suppress exudation of the molten glass.
(Atmospheric pressure) or less is more preferable.

The vacuum degassing apparatus for molten glass of the present invention can be applied to the case where the flow path of the molten glass which is in direct contact with the molten glass G is made of platinum or a noble metal such as platinum alloy such as platinum rhodium.

[0043]

As described above in detail, according to the vacuum degassing apparatus of the present invention, the depressurizing housing is vertically divided into multiple stages in the rising pipe and the descending pipe in which the liquid pressure of the molten glass is large. By forming multiple dividing chambers and increasing the pressure in the dividing chambers, the difference with the liquid pressure of the molten glass is reduced, and the force that the molten glass exudes from the flow path of the rising pipe and the descending pipe into the decompression housing is reduced. Since it has been suppressed, in a vacuum degassing apparatus for molten glass that removes bubbles from the continuously supplied molten glass, it has sufficient durability against high temperature molten glass and has excellent safety. A vacuum degassing apparatus can be provided. In particular, when the ascending pipe and the descending pipe are made of a furnace material, it is possible to prevent the shortened life due to the exudation of the molten glass.

Further, according to the present invention, since the pressures of the plurality of divided chambers are controlled by the pressure adjusting means so as to increase from the upper chamber toward the lower chamber, the pressure of the divided chambers is controlled by the liquid of the molten glass. The difference from the pressure can be suppressed to a small value, and thus the exuding force of the molten glass can be further suppressed.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of a vacuum degassing apparatus according to the present invention.

FIG. 2 is a diagram illustrating pressure control of each division chamber of the vacuum degassing apparatus shown in FIG.

FIG. 3 is a schematic sectional view of a conventional vacuum degassing apparatus for molten glass.

[Explanation of symbols]

10, 110 ... Vacuum degassing apparatus, 11, 114 ... Vacuum degassing tank, 12, 112 ... Vacuum housing, 12C, 112C
... Suction port, 13A-13E ... Dividing chamber, 14A-14E ...
Suction port, 15A, 15B, 15D, 15E ... Pressure adjusting device, 16, 116 ... Ascending pipe, 18, 118 ... Down pipe, 2
0, 120 ... Melting tank, 22, 122 ... Upstream pit, 2
4,124 ... Downstream pit, 30,130 ... Insulation material, G
… Molten glass

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hajime Ito             1150 Hazawa-machi, Kanagawa-ku, Yokohama-shi, Kanagawa             Asahi Glass Co., Ltd.

Claims (3)

[Claims] 1. A decompression housing that is vacuum-sucked to decompress the inside, a decompression defoaming tank provided in the decompression housing for decompressing molten glass under reduced pressure, and provided in communication with the decompression defoaming tank. An ascending pipe for sucking up the molten glass before vacuum degassing and introducing it into the vacuum degassing tank, and a molten glass after vacuum degassing, which is provided in communication with the vacuum degassing tank, descends from the vacuum degassing tank. At least one of the accommodating portion of the ascending pipe and the accommodating portion of the descending pipe of the decompression housing is divided into a plurality of divided chambers in a horizontal direction. Are arranged side by side in the vertical direction, and each of the divided chambers is provided with a pressure adjusting means capable of independently adjusting the pressure of each of the divided chambers. . 2. The molten glass according to claim 1, wherein the pressures in the plurality of divided chambers are controlled by the pressure adjusting means so that the pressures increase from the upper chamber toward the lower chamber. Vacuum degassing equipment. 3. When the minimum value of the liquid pressure of the molten glass in each of the division chambers is GPi and the pressure in the division chamber is HPi, 0.5 (atmospheric pressure) ≧ GPi−HPi ≧ 0 (atmospheric pressure). 3. The vacuum degassing apparatus for molten glass according to claim 1, which is controlled by the pressure adjusting means.