JPH11130444A - Reduced pressure deforming apparatus for molten glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the distortion and deterioration occurring in the thermal expansion of a reduced pressure housing and a reduced pressure deforming vessel and to improve the durability, etc., of the apparatus by dividing the main body part of the reduced pressure housing of a reduced pressure deforming apparatus to a riser housing section and a downcomer housing section and hermetically and expandably and contractably connecting respective disassembled disassembly pieces by means of buffer member. SOLUTION: This apparatus comprises a cylindrical reduced pressure deforming vessel 14 which executes reduced pressure deforming of the molten glass G, the riser 16 and downcomer 18 which are respectively disposed to communicate with the reduced pressure deforming vessel 14 and introduce the molten glass prior to reduced pressure deforming to the reduced pressure deforming vessel 14 and lead the molten glass after reduced pressure deforming out of the reduced pressure deforming 14, a main body section 12a which houses the reduced pressure deforming vessel 14, a riser housing section 12b which houses part of the riser 16 and a downcomer housing section 12c which houses part of the downcomer 18. The apparatus includes the reduced pressure housing 12 for executing vacuum suction. The main body section 12a of the reduced pressure housing 12 is disassembled at >=1 points between the riser housing section 12b and the downcomer housing section 12c. The respective disassembly pieces are connected hermetically and expandably and contractably connected by buffer members 36.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a vacuum degassing apparatus for molten glass for removing air 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 molten glass before forming the glass melted in a melting furnace with a forming apparatus has been known. Used. FIG. 4 shows such a conventional vacuum degassing apparatus. The vacuum degassing apparatus 10 shown in FIG.
Numeral 0 is used in a process of defoaming the molten glass G in the melting tank 112 under reduced pressure and continuously supplying the molten glass G to the next processing tank. A decompression degassing tank 104 is horizontally accommodated in a decompression housing 102, and an ascending pipe 106 and a descending pipe 108 vertically attached to both ends thereof are accommodated and arranged.

The rising pipe 106 communicates with the vacuum degassing tank 104, and the molten glass G before defoaming is lifted from the melting tank 112 and introduced into the vacuum degassing tank 104. The downcomer 108 is
The molten glass G after the defoaming process is communicated with the vacuum degassing tank 104.
Is lowered from the vacuum degassing tank 104 and led out to the next processing tank (not shown). Then, in the decompression housing 102, the decompression degassing tank 104, the rising pipe 106 and the downcomer 1
Around the area 08, a heat insulating material 110 such as a refractory brick for heat insulation that covers the heat insulating material is provided. The decompression housing 102 is made of metal, for example, stainless steel, is vacuum-sucked from the outside by a vacuum pump (not shown) or the like, decompresses the inside, and has a decompression degassing tank 104 installed therein.
The inside is maintained at a predetermined reduced pressure, for example, a reduced pressure of 1/20 to 1/3 atm.

In the conventional vacuum degassing apparatus 100, the molten glass G at a high temperature, for example, at a temperature of 1200 to 1400 ° C.
As described in Japanese Unexamined Patent Application Publication No. 2-221129 filed by the present applicant, a vacuum degassing tank 104, an ascending pipe 106, a descending pipe 108, etc. The portion that is in direct contact with the molten glass G is usually formed of a circular pipe made of a noble metal such as platinum or a platinum alloy such as platinum rhodium. Here, these are made of a circular tube made of a noble metal such as a platinum alloy because not only the molten glass G has a high temperature, but also the noble metal has a low high-temperature reactivity with the molten glass, and is heterogeneous due to the reaction with the molten glass. This is because the formation at a high temperature can be ensured to a certain degree without causing the formation of a layer. In particular, in addition to the above-mentioned reason, the vacuum degassing tank 104 is formed of a precious metal circular tube.
Is uniformly heated to maintain the temperature of the molten glass G at a predetermined temperature.

When the vacuum degassing tank 104 is made of a noble metal, it is preferable to use a circular tube from the viewpoint of high-temperature strength. However, since a noble metal such as platinum is expensive, its thickness cannot be increased, so that cost and strength are reduced. From both points, the diameter of the circular pipe is limited and cannot be so large,
There is also a limit on the flow rate of the molten glass G that can be defoamed by
There was a problem that a vacuum degassing apparatus with a large flow rate could not be constructed. Of course, it is conceivable to increase the total length of the cylindrical vacuum degassing tank 104 to increase the flow rate, thereby increasing the amount of degassing treatment. There is also a problem that the device becomes longer than in the case of the above. For this reason, there is also a problem that the degassing processing amount (flow rate) of the molten glass G in the vacuum degassing apparatus 100 cannot be increased.

Since the molten glass G is obtained by melting and reacting the powdery raw material, it is preferable that the temperature of the melting tank 112 be higher in terms of melting, and that the molten glass G be reduced in terms of degassing under reduced pressure. It is preferred that the viscosity be low and therefore the temperature be high. However, while it is necessary to use a noble metal alloy in the vacuum degassing tank 104 and the like from the viewpoint of high temperature strength,
Since the noble metal is expensive and the thickness of the circular tube cannot be increased so much from the viewpoint of cost, if a noble metal such as platinum is used, the temperature of the molten glass G at the inlet of the vacuum degassing apparatus 100 becomes the above-mentioned predetermined temperature. (1200-1400 ° C.).

[0007]

In order to solve such a problem, the vacuum degassing tank 104, the riser pipe 106 and the descender pipe 108 are made of a refractory which is less expensive than a noble metal alloy.
If the molten glass can be continuously depressurized and degassed as in the case of precious metal alloys, the amount of use can be limited from the viewpoint of cost compared to the case of using precious metal alloys such as platinum, and the reduction in strength accompanying it can be reduced. It is no longer necessary to limit the size from the point of view, and the degree of freedom in equipment design is dramatically improved, so that it is possible to construct a vacuum degassing apparatus with a large flow rate and to decompress at a higher temperature. It is believed that processing will also be possible.

However, even when a vacuum degassing tank or the like is made of a refractory material, as in the case of a platinum alloy,
There is a problem that thermal expansion occurs due to heating. As a method of efficiently absorbing the thermal expansion of the vacuum degassing tank itself and removing distortion in the apparatus, in the case of a platinum alloy, a plurality of platinum alloy cylinders themselves constituting the vacuum degassing tank are used. This has been dealt with by providing a flange so as to be able to expand and contract according to thermal expansion. On the other hand, in the case of the above-mentioned refractory, since the bellows cannot be constituted by the refractory having poor ductility itself, there is a problem how to escape the thermal expansion. Also, if the thermal expansion cannot be sufficiently released, distortion will occur in the device, and in the worst case, it will lead to breakage, especially at the joint between the vacuum degassing tank and the ascending pipe, descending pipe. When this occurs, there is a problem that the safety of the device may be impaired, for example, the device is easily damaged.

Further, the refractory constituting the vacuum degassing tank or the like once thermally expands and then contracts due to a decrease in temperature.
In the case of refractories containing zirconium oxide, whose temperature dependence of the thermal expansion coefficient behaves in a unique way, the refractory contracts while maintaining its position after thermal expansion, so the shrinkage forms a gap. As a result, the joint is opened, and there is a problem that molten glass may leak from the opened joint.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art. In a vacuum degassing apparatus for molten glass, which removes air bubbles from a continuously supplied molten glass, a high-temperature molten glass is used. It is an object of the present invention to provide a vacuum degassing apparatus for molten glass having sufficient durability and excellent safety.

[0011]

In order to achieve the above object, the present invention provides a cylindrical vacuum degassing tank for performing vacuum degassing of molten glass, and is provided in communication with the vacuum degassing tank. Introducing means for introducing the molten glass before the vacuum degassing into the vacuum degassing tank, and provided in communication with the vacuum degassing tank, and leading the molten glass after the vacuum degassing from the vacuum degassing tank. A deriving unit, a main unit that stores the vacuum degassing tank, an introducing unit receiving unit that partially stores the introducing unit, and a deriving unit receiving unit that partially stores the deriving unit. And a main body portion of the decompression housing is divided at least at one portion between the introduction means accommodating section and the derivation means accommodating section, and each of the divided pieces is airtight and stretchable. It is characterized by having a shock-absorbing member Providing vacuum degassing apparatus for molten glass to.

[0012] Here, fixing means provided at one longitudinal end of the vacuum degassing tank for fixing the vacuum degassing tank, and fixing means provided at the other longitudinal end of the vacuum degassing tank. And a biasing means for biasing the vacuum degassing tank toward the fixing means.

[0013] Further, of the divided pieces constituting the main body portion of the decompression housing, a support means for supporting the divided piece provided with the fixing means so that the decompression housing has a predetermined height, and It is preferable to have movable support means for supporting the divided piece so as to be movable in the longitudinal direction of the vacuum degassing tank and for supporting the vacuum housing at the predetermined height.

Further, the introduction means is a riser pipe which raises and introduces the molten glass before the vacuum degassing into the vacuum degassing tank, and the lead-out means sets the molten glass after the vacuum degassing and degassing. It is a downcomer that descends from the vacuum degassing tank and leads out, and further, at least one of the upper surface of the riser and the downcomer is formed in a hemispherical shape, and the hemispherical surface in the vacuum degassing vessel. It is preferable that the contact portion is formed in a hemispherical shape that can be fitted to the hemispherical surface.

Further, it is preferable that at least a main part of the introducing means, the vacuum degassing tank and the deriving means, which is in direct contact with the molten glass, is formed of an electroformed refractory.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a vacuum degassing apparatus for molten glass of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.

FIG. 1 is a schematic sectional view of a vacuum degassing apparatus for molten glass of the present invention. As shown in FIG. 1, the vacuum degassing apparatus 10 performs a degassing process on the molten glass G in the melting tank 20 under reduced pressure to form a next processing tank (not shown), for example, a plate material forming processing tank such as a float bath or a bottle. It is used in the process of continuously supplying to molding work tanks and the like.
It has a decompression housing 12, a decompression degassing tank 14, an ascending pipe 16 and a descending pipe 18. The decompression housing 12 is for ensuring the airtightness of the decompression degassing tank 14, is formed in a substantially portal shape, and includes a main body 12a, an ascending pipe housing 12b,
And a downcomer receiving section 12c. This decompression housing 1
2 is not particularly limited in its material and structure as long as it has the airtightness and strength required for the vacuum degassing tank 14, but is preferably made of metal, particularly stainless steel. Such a decompression housing 12 is vacuum-evacuated from the outside by a vacuum pump (not shown) or the like, and the inside thereof is decompressed. It is configured to maintain a reduced pressure of 3 atm.

A vacuum degassing tank 14 is provided in the main body 12a of the pressure reducing housing 12. A rising pipe 16 communicates with the left end of the vacuum degassing tank 14, and a downcomer pipe 18 communicates with the right end of the vacuum degassing tank 14. The main parts of the riser pipe 16 and the lowering pipe 18 are respectively connected to
The lower end portions of the ascending pipe 16 and the descending pipe 18 are accommodated in the ascending tube accommodating portion 12b and the descending tube accommodating portion 12c, respectively.

In the vacuum degassing apparatus 10 of the present invention, the materials of the vacuum degassing tank 14, the riser tube 16 and the downcomer tube 18 are not particularly limited, and noble metal alloys such as platinum or platinum alloys such as platinum rhodium and platinum palladium are used. And electroformed refractories. Among them, it is preferable to use electroformed refractories. That is, the molten glass G in the vacuum degassing apparatus 10
By forming the main part that is in direct contact with the electroformed refractory, the cost is greatly reduced compared to the conventionally used one made of a precious metal alloy, and therefore, the free shape and the free thickness Because it becomes possible to design
This is because the capacity of the vacuum degassing apparatus 10 can be increased and the vacuum degassing process at a higher temperature can be performed.

Therefore, the shapes of the vacuum degassing tank 14, the riser pipe 16 and the descender pipe 18 are not particularly limited as long as they are at least cylindrical. For example, the cross-sectional shape may be not only circular but also rectangular. . Vacuum degassing tank 14, using electroformed refractories,
The method of constructing the riser pipe 16 and the downcomer pipe 18 is not particularly limited. For example, small rectangular parallelepiped electroformed bricks are alternately stacked three-dimensionally, that is, in a jointed joint structure, and the joint portion therebetween is jointed with jointing material. Filling, a tubular tube of a predetermined length may be formed, or cylindrical electroformed bricks cast and formed into a cylindrical shape or a square tubular shape are stacked in a row, and the joint portion therebetween is filled with a joint material, A cylindrical tube having a predetermined length may be formed.

In particular, as shown in FIG. 3, the side surface of the vacuum degassing tank 14 has a pressing structure in which the electroformed brick 30 constituting the lower side surface is protruded upward. Applying a force from above is preferable because displacement of joints can be prevented and joints can be firmly tightened. In particular, it is very effective when the fixing means 40 and the urging means 46 described later are provided.

Even when an electroformed refractory is used, the lower end of the rising pipe 16 which is immersed in the molten glass G in the upstream guide duct 20 or the lower end of the descending pipe 18 will be described later. The portion of the casing 52 to be immersed in the molten glass G is particularly rich in the vicinity of the interface between the molten glass G and the atmosphere because of the presence of the interface between the molten glass G and the atmosphere. Deterioration of the part is easy to progress. Therefore, the lower end of the riser 16 and the lower end of the downcomer 18 are preferably made of platinum or a platinum alloy.

The electroformed refractory is not particularly limited as long as the refractory raw material is electromelted and then cast into a predetermined shape, and various conventionally known electroformed refractories may be used. Among them, in terms of high corrosion resistance and little foaming from the substrate, alumina-based electroformed refractories, zirconia-based electroformed refractories,
AZS (Al ₂ O ₃ —ZrO ₂ —SiO ₂ ) based electroformed refractories are preferably exemplified, and specifically, masonite (M
BG), ZB-X950, and zirconite (ZB) (all manufactured by Asahi Glass Co., Ltd.).

A refractory brick 32 for heat insulation (hereinafter referred to as a heat insulating brick 32) for covering the vacuum degassing tank 14 is provided around the vacuum degassing tank 14. Insulated bricks 32 that cover each area
Is arranged. Various known bricks may be used as the heat insulating bricks 32, and there is no particular limitation. The heat insulating brick 32 arranged in this manner is accommodated in the decompression housing 12 by covering the outside thereof with the decompression housing 12. Note that the temperature of the outer wall surface of the decompression housing 12 is preferably set to be as low as possible, for example, about 100 ° C., by blocking the heat transmitted to the decompression housing 12 by the heat insulating bricks 32 as much as possible.

Further, around the vacuum degassing tank 14, the riser pipe 16 and the descender pipe 18, if necessary, a heat insulating brick 32
In addition, a configuration may be adopted in which a heater can be provided to enable heating, or a configuration in which cooling water is allowed to pass and cooling is possible.

As described above, in the vacuum degassing apparatus of the illustrated example, at least the main parts of the vacuum degassing tank 14, the riser pipe 16 and the downcomer pipe 18 which are in direct contact with the molten glass G are formed of the electroformed refractory. Things. Therefore, as described above, since it is not possible to provide a structure capable of expanding and contracting by providing a flange in a vacuum degassing tank as in the case of a platinum alloy having high ductility, how to escape thermal expansion is a problem. Become.
In addition, if the thermal expansion cannot be sufficiently released, distortion occurs in the device, and in the worst case, there is a problem that the safety of the device may be impaired, such as damage. Furthermore, when the refractory constituting the vacuum degassing tank or the like once thermally expands and then contracts, there is a problem that joints are opened and molten glass may leak.

In the present invention, the main body 12a of the decompression housing is divided into an ascending tube accommodating portion 12b and a descending tube accommodating portion 12c.
The above-mentioned problem has been solved by providing a buffer member 36 which is divided at least at one point between the two and the divided components (hereinafter, referred to as divided pieces) are connected in an airtight and stretchable manner. It is. That is, the buffer member 36 provided in the decompression housing 12 absorbs the thermal expansion of the vacuum degassing tank 14, for example, the electroformed refractory constituting the vacuum degassing device 14 and the insulating brick 32 covering the periphery thereof. Accordingly, it is possible to prevent distortion and deterioration due to thermal expansion of the decompression housing 12 itself and the decompression and deaeration tank 14 housed in the housing 12, thereby improving the safety of the apparatus.

More specifically, as shown in FIG. 1, two buffer members 36 are provided in the main body 12a of the decompression housing. The buffer member 36 is for absorbing thermal expansion of the vacuum degassing tank 14 and the heat insulating bricks 32 surrounding the same to prevent distortion and deterioration of the vacuum housing 12, and is a main body 12a of the vacuum housing. In this manner, each of the divided pieces cut and divided between the riser tube accommodating portion 12b and the descending tube accommodating portion 12c is provided in an airtight and stretchable manner. The cushioning member 36 is not particularly limited as long as it has strength and airtightness that does not impair the function of the decompression housing 12 and can expand and contract, and various conventionally known members can be used. It is preferable to use a metal cylindrical bellows in view of strength, airtightness and elasticity, and a stainless steel bellows is preferably exemplified.

The number of cushioning members 36 provided is not particularly limited, and may be any number as long as it is at least one or more. For example, the main body 12a of the decompression housing is divided into three divided pieces: a divided piece 13a on the riser pipe 16 side, a central divided piece 13b, and a divided piece 13c on the descending pipe 18 side. 60 is the center split piece 1
3b, which is preferable because the entire vacuum degassing apparatus can be supported in a balanced manner at at least three points. Alternatively, the movable support means 60 may be provided on the left and right divided pieces 13a and 13c to fix the central divided piece 13b.

Further, as shown in FIG. 1, the vacuum degassing tank 14 is preferably provided with fixing means 40 and urging means 46. The fixing means 40 is connected to one end of the vacuum degassing tank 14 in the longitudinal direction (the end 1 on the riser pipe 16 side in the illustrated example).
4a) is to be fixed at a predetermined position, and its material and structure are not particularly limited, and various fixing means can be used. For example, as shown in the drawing, a plate member 42 joined to the end surface of the vacuum degassing tank 14 and a rod member 44 provided to be connected to the plate member 42 and having the other end fixed to a tank kiln load receiving steel material (not shown) or the like. What is necessary is just to comprise from. The bar 44 is sealed at a portion penetrating the decompression housing 12. The plate member 42 and the bar member 44 are preferably made of stainless steel in view of strength and corrosion resistance. The number of the bar members 44 is not particularly limited. This is preferable in that the entire end face of the foam tank 14 can be fixed.

The urging means 46 includes the other end of the vacuum degassing tank 14,
In other words, the side where the fixing means 40 is not provided (the end 14b on the side of the downcomer pipe 18 in the illustrated example) is urged toward the fixing means 40 so that the shape of the vacuum degassing tank 14 is maintained at a constant pressure. , To tighten the joints firmly,
The material and structure are not particularly limited, and various urging means can be used. For example, as shown in the illustrated example, the vacuum degassing tank 1
4, a pressing member 50 provided adjacent to the plate member 48, and a pressing member 50
And a bar 52 fixed at one end to a tank furnace load receiving steel (not shown) or the like. The bar 52 is sealed at a portion penetrating the decompression housing 12. The plate member 48 and the bar members 52 are preferably made of stainless steel, similarly to the fixing means 40. The numbers of the urging members 50 and the bar members 52 are not particularly limited,
The vacuum degassing tank 1 is provided in a plurality (for example, two).
4 is preferable in that the entire end face can be biased. As the urging member 50, various known springs such as a disc spring and a leaf spring can be used. However, a disc spring is used because it is easy to apply an arbitrary compressive force by combining a plurality of springs. Is preferred.

As described above, by providing the fixing means 40 and the urging means 46 at both ends of the vacuum degassing tank 14, even if thermal expansion or contraction (at the time of cooling) of the refractory occurs, the joint is firmly tightened. And leakage of the molten glass from the joint can be effectively prevented. Further, while maintaining the shape of the vacuum degassing tank 14, the thermal expansion of the vacuum degassing tank 14 may be released in one direction, that is, the urging direction of the urging means 50 (the longitudinal direction of the vacuum degassing tank 14). Therefore, it is possible to more effectively prevent the occurrence of distortion in the device due to thermal expansion, and to obtain an effect of improving the safety of the device. The fixing means 40 and the urging means 46 may be configured in a manner opposite to the illustrated example, that is, the fixing means 40 is provided on the downcomer pipe 18 side and the urging means 46 is provided on the ascending pipe 16 side. .

By the way, in the vacuum degassing apparatus as shown in the figure, the lowermost portion is buried in the molten glass, so that it does not become a fulcrum. Since the center of gravity is higher than the fulcrum and the installation of the device is difficult due to lack of stability, it is general that the main body 12a of the decompression housing 12 is lifted and supported by the support means. Here, in the vacuum degassing apparatus 10 of the present invention, as shown in FIG. 1, it is preferable that such a supporting means is constituted by combining a fixed supporting means 54 and a movable supporting means 60. That is, 13 of the divided pieces on the riser 16 side.
A is provided with fixed support means 54 for supporting the lower end thereof, and movable support means 60, 60 for supporting the lower end thereof at the central portion and the divided pieces 13b, 13c on the side of the downcomer 18 respectively.

The fixed supporting means 54 is for supporting the vacuum degassing apparatus 10 together with the vacuum housing 12 at a predetermined height, and is provided with a divided piece provided with the fixing means 40 (in the illustrated example, on the side of the rising pipe 16). It is provided at the lower end of the segment 13a).
As the fixed support means 54, it is preferable to use a support means which can be moved up and down in that the pressure reduction condition and the like can be appropriately adjusted by changing the height of the apparatus. For example, as shown in the illustrated example, a jack or the like is used. And a spacer 58 provided on the lifting device 56.

The movable support means 60 is a divided piece other than the divided piece supported by the fixed support means 54 (in the illustrated example, the central divided piece 13b and the divided piece 13c on the downcomer pipe 18 side).
Is provided at the lower end of the vacuum decompression housing 12 at a predetermined height, and is configured to be movable in the longitudinal direction of the vacuum degassing tank 14. For example, a lifting device 62 such as a jack, What is necessary is just to comprise the roller 64 rotatably provided on the raising / lowering apparatus 62. Roller 6
4 may be provided for each divided piece.
In place of the above, a wheel on a rail or a ball bearing passing through a steel bar instead of the rail may be used.

As described above, one divided piece (the divided piece 13a on the riser tube 16 side in the illustrated example) of the decompression housing 12 is fixedly supported by the fixed support means 56, and the other divided piece (the In the illustrated example, the center divided piece 13
b, and the divided piece 13c) on the side of the downcomer pipe 18 are supported by the movable supporting means 60 so as to be movable in the longitudinal direction of the decompression degassing tank 14, so that the thermal expansion of the decompression housing 12 itself is released and the decompression housing is released. The expansion and contraction of the buffer member 36 caused by the thermal expansion of the inside 12, particularly the vacuum degassing tank 14, can be performed smoothly, and the distortion of the vacuum housing 12 can be more effectively removed, and the safety of the apparatus can be further enhanced. be able to.

The portion where the downcomer 18 and the vacuum degassing layer 14 are joined (hereinafter, referred to as a joining portion 66) is preferably formed in a hemispherical shape. Specifically, as shown in FIG. 2, the upper end surface of the downcomer pipe 18 is formed in a convex shape, and the joint on the reduced pressure degassing tank 14 side in contact with the upper end is formed into a concave shape that can be fitted with the convex surface. It is preferable to form it. In this way, even if the vacuum degassing tank 14 thermally expands in its longitudinal direction and the distance between the cores of the riser 16 and the downcomer 18 fluctuates, the downcomer 18 is removed from the vacuum degasser. Since it is possible to smoothly follow the thermal expansion of the joint 14, the concentration of stress in the joint 66 is reduced, and the deterioration and breakage of the joint 66 due to the thermal expansion and contraction of the vacuum degassing tank 14 are prevented. At the same time, it is possible to prevent the joint from being opened in the vicinity of the joint portion 66 and to prevent the molten glass from leaking. Either the downcomer 18 or the vacuum degassing tank 14 may be formed in a concave shape (or a convex shape). Therefore, the upper end of the downcomer 18 is formed in a concave shape, and the joining at the vacuum degassing section 14 side is performed. The portion 66 may be formed in a convex shape. Further, such a joint may be applied not only to the downcomer pipe 18 but also to the ascending pipe 16, but applying to the joint with the pipe on the side where the urging means 46 is provided reduces thermal expansion and contraction. This is preferable in that it can be efficiently released in one direction.

An example of a process for defoaming the molten glass G by the vacuum degassing apparatus 10 of the present invention and continuously supplying the same to the next processing furnace will be described below. First, the inside of the vacuum housing 12 and the vacuum degassing tank 14 are maintained in a vacuum suction state by a vacuum pump (not shown). In this state, the glass G melted in the melting tank 20 rises through the guide duct 20 through the riser pipe 16 and is guided into the vacuum degassing tank 14, and the molten glass G is brought into the vacuum degassing tank 14. Defoaming is performed under reduced pressure. Then, the defoamed molten glass G is supplied to the downcomer 1
8 to the canal 24.

In the vacuum degassing apparatus shown in the drawing, the vacuum degassing tank 14, the riser pipe 16 and the downcomer pipe 18 are formed at least in a main part which is in direct contact with the molten glass by an electroformed refractory. However, the present invention is not limited to this,
It is also applicable to those made of platinum alloy. The present invention is not limited to the siphon-type vacuum degassing apparatus shown in FIG. 2, but is also disclosed in JP-A-5-262530 and JP-A-7-291.
As a matter of course, the present invention may be applied to a horizontal vacuum degassing apparatus described in JP-A-633.

Although the vacuum degassing apparatus for molten glass according to the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the gist of the present invention. Of course, you may.

[0041]

As described in detail above, according to the present invention, in a vacuum degassing apparatus for molten glass for removing bubbles from a continuously supplied molten glass, a high-temperature molten glass can be used. With sufficient durability and excellent safety,
A vacuum degassing apparatus for molten glass can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a vacuum degassing apparatus of the present invention.

FIG. 2 is a schematic cross-sectional view showing a joint between a downcomer pipe and a vacuum degassing apparatus in the vacuum degassing apparatus shown in FIG.

FIG. 3 is a schematic view showing a side surface of a vacuum degassing tank in the vacuum degassing apparatus shown in FIG.

FIG. 4 is a schematic sectional view showing an example of a conventional vacuum degassing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Decompression degassing apparatus (of molten glass) 12 Decompression housing 14 Decompression housing 16 Ascending pipe 18 Downcoming pipe 20 Melting tank 22 Upstream guide duct 24 Canal 32 Insulating brick 36 Buffer member 40 Fixing means 42,48 Plate 44,52 Rod Material 46 urging means 50 urging member 54 fixed support means 56, 62 elevating device 58 spacer 60 movable support means 64 roller 66 joint

Continued on the front page (72) Inventor Shoji Imamaki 1-1, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside the Keihin Plant of Asahi Glass Co., Ltd.

Claims (5)

[Claims] 1. A vacuum degassing tank having a cylindrical shape for performing degassing of molten glass under reduced pressure, and provided in communication with the vacuum degassing tank. The molten glass before the degassing is introduced into the vacuum degassing tank. Introducing means for providing, a deriving means provided in communication with the vacuum degassing tank, and a deriving means for deriving the molten glass after the vacuum degassing from the vacuum degassing tank; An introduction means accommodating part accommodating a part of the introduction means, and a decompression means accommodation part accommodating a part of the derivation means, which is provided with a decompression housing which is suctioned under vacuum; Is divided at at least one place between the introduction means accommodating section and the deriving means accommodating section, and has a buffer member for connecting each of the divided pieces in an airtight and stretchable manner. Vacuum deaerator. 2. A fixing means provided at one longitudinal end of the vacuum degassing tank for fixing the vacuum degassing tank, and a fixing means provided at the other longitudinal end of the vacuum degassing tank. 2. A vacuum degassing apparatus for molten glass according to claim 1, further comprising: urging means for urging said vacuum degassing tank toward said fixing means. 3. A divided piece provided with the fixing means among the divided pieces constituting the main body of the decompression housing,
A supporting means for supporting the decompression housing at a predetermined height; and another divided piece movably in the longitudinal direction of the decompression tank, and supporting the decompression housing at the predetermined height. 3. A movable supporting means comprising:
2. A vacuum degassing apparatus for molten glass according to item 1. 4. The introduction means is an ascending pipe that raises and introduces the molten glass before the decompression degassing into the decompression degassing tank, and the derivation means removes the molten glass after the decompression degassing from the molten glass. It is a downcomer pipe that descends from the vacuum degassing tank and is drawn out, and further, the upper end surface of at least one of the riser pipe and the downcomer pipe is formed in a hemispherical shape, and the hemispherical surface in the vacuum degassing vessel. The vacuum degassing apparatus for molten glass according to any one of claims 1 to 3, wherein a contacting portion is formed in a hemispherical shape capable of fitting with the hemispherical surface. 5. The apparatus according to claim 1, wherein said introducing means, said vacuum degassing tank and said deriving means have at least a main part which is in direct contact with said molten glass formed of an electroformed refractory. A vacuum degassing apparatus for molten glass as described in the above.