JP3817868B2 - Vacuum degassing equipment for molten glass - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of a vacuum degassing apparatus for molten glass that removes bubbles from continuously supplied molten glass.
[0002]
[Prior art]
Conventionally, in order to improve the quality of a molded glass product, a vacuum degassing apparatus that removes bubbles generated in the molten glass before the molten glass melted in the melting furnace is molded by a molding apparatus has been used. . Such a conventional vacuum degassing apparatus is shown in FIG. The vacuum degassing apparatus 100 shown in FIG. 3 is used in a process of vacuum degassing the molten glass G in the melting tank 112 and continuously supplying the molten glass G to the next processing tank. Yes. A decompression defoaming tank 104 is accommodated and disposed horizontally in the decompression housing 102, and an ascending pipe 106 and a descending pipe 108 attached vertically to both ends thereof are accommodated.
[0003]
The ascending pipe 106 communicates with the vacuum degassing tank 104 to raise the molten glass G before the defoaming treatment from the melting tank 112 and introduce it into the vacuum degassing tank 104. The downcomer 108 communicates with the vacuum degassing tank 104, lowers the molten glass G after the defoaming process from the vacuum degassing tank 104, and guides it to the next processing tank (not shown). In the reduced pressure housing 102, a heat insulating material 110 such as a heat insulating brick is provided around the reduced pressure defoaming tank 104, the ascending pipe 106, and the descending pipe 108 to insulate them. Note that the decompression housing 102 is made of metal, for example, stainless steel, and is vacuumed from the outside by a vacuum pump (not shown) or the like, the inside is decompressed, and the inside of the decompression deaeration tank 104 is set to a predetermined decompression. For example, the pressure is maintained at a reduced pressure of 1/20 to 1/3 atm.
[0004]
Since the conventional vacuum degassing apparatus 100 is configured to process a molten glass G at a high temperature, for example, 1200 to 1400 ° C., it is disclosed in Japanese Patent Application Laid-Open No. 2-221129 relating to the application of the present applicant. As shown in the figure, the portions that are in direct contact with the molten glass G, such as the vacuum degassing vessel 104, the rising pipe 106, and the downfalling pipe 108, are usually circular tubes made of noble metal such as platinum or a platinum alloy such as platinum rhodium. It is configured.
Here, these are constituted by noble metal circular tubes such as platinum alloys because not only the molten glass G is hot, but also the noble metal has low high temperature reactivity with the molten glass and is inhomogeneous due to reaction with the molten glass. This is because the strength at a high temperature can be secured to some extent without causing any deterioration.
In particular, the vacuum defoaming tank 104 is composed of a noble metal circular tube, in addition to the above reasons, a current is passed through the noble metal circular tube itself to cause self-heating, and the molten glass G in the cylinder is heated uniformly and melted. This is to keep the temperature of the glass G at a predetermined temperature.
[0005]
By the way, 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 noble metals such as platinum are expensive, the thickness cannot be increased . Therefore, there is a limit to the diameter of the circular tube in terms of both cost and strength, the diameter of the circular tube cannot be increased so much, and the flow rate of the molten glass G that can be defoamed in the vacuum degassing tank 104 is also limited. There was a problem that it was not possible to construct a vacuum degassing apparatus with a large flow rate. Of course, it is conceivable to increase the defoaming amount by increasing the overall length of the tubular vacuum degassing tank 104 and increasing the flow rate, but in comparison with the processing amount, the dissolution tank, the molding processing tank, etc. Compared to the above, there is a problem that the apparatus becomes longer. For this reason, there also existed a problem that the defoaming processing amount (flow rate) of the molten glass G in the vacuum degassing apparatus 100 could not be enlarged.
[0006]
In addition, since the molten glass G is obtained by dissolving the powder raw material, the temperature of the melting tank 112 is preferably higher in terms of melting, and the viscosity of the molten glass is low in terms of vacuum degassing. Therefore, a higher temperature is preferred. However, while it is necessary to use a noble metal alloy for the vacuum degassing tank 104 or the like from the viewpoint of high temperature strength, the noble metal is expensive, and the thickness of the circular tube cannot be increased so much from the point of cost. Is used, the temperature of the molten glass G at the inlet of the vacuum degassing apparatus 100 has been limited to the above-described predetermined temperature (1200 to 1400 ° C.).
[0007]
[Problems to be solved by the invention]
By the way, with respect to such a problem, the decompression defoaming tank 104, the rising pipe 106 and the descending pipe 108 are made of a refractory brick which is cheaper than the noble metal alloy, and the molten glass is continuously decompressed as in the case of the noble metal alloy. If it can be defoamed, there is no need to limit the amount used from the point of cost or the size from the point of strength reduction, compared to the case of using a noble metal alloy such as platinum, Since the degree of freedom in device design is dramatically improved, it is considered that a vacuum degassing device having a large flow rate can be constructed and a vacuum degassing treatment at a higher temperature can be performed.
[0008]
However, if all the components of the vacuum degassing apparatus 100 are made of refractory bricks, there are the following problems. That is, in the tubular open ends such as the lower end portions of the ascending pipe 106 and the descending pipe 108, there is nothing to support the lower end, so that a heavy refractory brick is supported only by the adhesive force of the joint material. Therefore, sufficient strength cannot be obtained, and instead, even if it is attempted to manufacture a long cylindrical refractory brick, the cost becomes very high. For this reason, there is a problem that it is practically difficult to manufacture the lower ends of the ascending pipe 106 and the descending pipe 108 with refractory bricks.
[0009]
Even if the lower ends of the ascending pipe 106 and the descending pipe 108 are made of refractory bricks in this way, damage and deterioration are likely to occur at the joints, and even in parts other than the joints, At a position near the interface between the molten glass G and the atmosphere, there is a problem that the refractory is rich in reactivity and easily deteriorates because the atmosphere exists at a high temperature. When the joint portion and the interface portion deteriorate in this way, the lower end portions of the ascending pipe 106 and the descending pipe 108 become uneven in the height direction, causing breakage such as cracks, and in the worst case, the ascending pipe There is a possibility that part of the lower end portion of 106 and the downcomer pipe 108 may be broken and fall, and there is a problem that sufficient durability cannot be obtained. Furthermore, if the broken refractory is mixed into the molten glass G, there is a problem that the uniformity of the glass composition may not be maintained.
[0010]
An object of the present invention is to solve the above-mentioned problems of the prior art, and in a vacuum degassing apparatus for molten glass that removes bubbles from continuously supplied molten glass, it is sufficient for high-temperature molten glass. An object of the present invention is to provide a vacuum degassing apparatus for molten glass that can significantly reduce costs while ensuring high durability, and that can increase the capacity of the apparatus and increase the temperature of the vacuum defoaming treatment.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a vacuum housing that is evacuated, a vacuum defoaming tank that is provided in the vacuum housing and degassed molten glass, and communicates with the vacuum degassing tank. A riser pipe that raises the molten glass before the vacuum degassing and introduces it into the vacuum degassing tank; and is provided in communication with the vacuum degassing tank; A downcomer pipe that descends from the vacuum degassing tank, and an extension pipe provided in communication with the lower ends of the ascending pipe and the downcomer pipe, and the ascending pipe, the vacuum defoaming tank, and the downcomer pipe are The present invention provides a vacuum degassing apparatus for molten glass, wherein at least a portion in direct contact with the molten glass is formed of an electroformed brick, and the extension tube is formed of platinum or a platinum alloy.
[0012]
The extension pipe has a flange formed at the upper end thereof, and the flange is inserted into a joint of the electroformed brick forming the rise pipe or the down pipe, so that the rise pipe or the down pipe is inserted. It is preferably fixed to a tube.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the vacuum degassing apparatus for molten glass of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
[0014]
In FIG. 1, the schematic sectional drawing of the vacuum degassing apparatus of the molten glass of this invention is shown.
As shown in FIG. 1, the vacuum degassing apparatus 10 performs a vacuum degassing treatment on the molten glass G in the melting tank 20 to form a next processing tank (not shown) such as a plate-shaped molding processing tank such as a float bath, It is used in a process for continuously supplying to a molding work tank such as a bottle, and basically has a decompression housing 12, a decompression defoaming tank 14, a riser pipe 16, a downfall pipe 18, and extension pipes 26 and 28.
The decompression housing 12 is for ensuring the airtightness of the decompression defoaming tank 14, and is formed in a substantially gate shape. The material and structure of the decompression housing 12 are not particularly limited as long as the decompression housing 12 has airtightness and strength required for the decompression defoaming tank 14, but is made of metal, particularly stainless steel. Is preferred. Such a decompression housing 12 is vacuum-sucked by a vacuum pump (not shown) or the like from the outside, the interior is decompressed, and a predetermined decompression, for example 1/20 / It is configured to maintain a reduced pressure state of 3 atm.
[0015]
A vacuum degassing tank 14 is provided in the upper part of the vacuum housing 12. A rising pipe 16 communicates with the left end of the vacuum degassing tank 14, and a down pipe 18 communicates with the right end of the vacuum degassing tank 14. The ascending pipe 16 and the descending pipe 18 are respectively disposed in legs 12a and 12b of the decompression housing 12 (hereinafter referred to as housing legs 12a and 12b, respectively).
[0016]
In the vacuum degassing apparatus 10 of the present invention, the vacuum degassing tank 14, the rising pipe 16 and the descending pipe 18 are all formed of the electroformed brick 30.
That is, by forming the main part in direct contact with the molten glass G in the vacuum degassing apparatus 10 with the electroformed brick 30, the cost is significantly reduced as compared with those conventionally made of platinum alloys, and therefore Since it is possible to design in a free shape and a free thickness, it is possible to increase the capacity of the vacuum degassing apparatus 10 and to perform vacuum degassing at a higher temperature. Moreover, if it is an electrocast brick, since it is excellent in durability at high temperature compared with a general brick and the elution of a component can also be made into the minimum, the uniformity of a molten glass can be maintained.
[0017]
Accordingly, the shape of the vacuum degassing tank 14, the rising pipe 16 and the downfalling pipe 18 is not particularly limited as long as it is at least cylindrical. For example, the cross-sectional shape may be not only circular but also square. The method of constructing the vacuum degassing tank 14, the rising pipe 16 and the downfalling pipe 18 using the electroformed brick 30 is not particularly limited. For example, the small rectangular parallelepiped electrocast bricks 30 are stacked, and the joint portion between them is jointed. A cylindrical tube of a predetermined length may be formed by filling with a material, or cylindrical electroformed bricks 30 cast into a cylindrical shape or a rectangular tube shape are stacked in a line, and the joint portion between them is a joint material. The tube may be filled with a predetermined length to form a cylindrical tube.
[0018]
The electrocast brick 30 is not particularly limited as long as it is a brick that is electrically melted and then cast into a predetermined shape, and conventionally known various electrocast bricks may be used. Among them, alumina type electrocast refractories, zirconia type electrocast refractories, AZS (Al ₂ O ₃ —ZrO ₂ —SiO ₂ ) type electrocast refractories and the like are high in corrosion resistance and less foaming from the substrate. Illustrative examples include marsnite (MB-G), ZB-X950, zirconite (ZB) (all manufactured by Asahi Glass Co., Ltd.) and the like.
[0019]
A heat insulating brick 32 (hereinafter referred to as a heat insulating brick 32) covering the vacuum degassing tank 14 is disposed around the vacuum degassing tank 14, and is also provided around the ascending pipe 16 and the descending pipe 18, respectively. A heat insulating brick 32 is disposed to cover the surface.
As the heat insulating brick 32, known various bricks may be used and are not particularly limited. The heat insulating bricks 32 arranged in this way are accommodated in the decompression housing 12 by covering the outside with the decompression housing 12.
[0020]
Moreover, it is good also as a structure which can provide a heating heater with the heat insulation brick 32 around the decompression degassing tank 14, the riser pipe 16, and the downfall pipe 18 as needed, and it can let cooling water pass through. It is good also as a structure which can be cooled.
[0021]
Here, the lower end portion of the ascending pipe 16 needs to be fitted into the open end of the upstream pit 22 and immersed in the molten glass G in the upstream pit 22. Similarly, the lower end portion of the downcomer 18 needs to be fitted into the open end of the downstream pit 24 and immersed in the molten glass G in the downstream pit 24.
By the way, as described above, the vacuum degassing apparatus 10 of the present invention is configured such that the main part is the electroformed brick 28.
[0022]
However, as described above, even if the lower end portion of the rising pipe 16 and the portion that is inserted into the upstream pit 22 and is immersed in the molten glass G is to be produced with the electroformed brick 30, it is realistic from the viewpoint of strength and cost. However, even if it is produced with the electroformed brick 30, there is a problem that the joint portion and the interface portion are likely to be deteriorated, and there is a possibility that breakage such as cracking may occur, and sufficient durability cannot be obtained. .
Further, when the electroformed brick 30 is used to produce a portion that is inserted into the open end of the downstream pit 24 and is immersed in the molten glass G at the lower end of the downcomer pipe 18, there is the same problem as described above.
[0023]
On the other hand, in the present invention, as shown in FIG. 1, extension pipes 26 and 28 made of platinum or a platinum alloy are provided at the lower end portions of the ascending pipe 16 and the descending pipe 18, respectively. The pits 20 and the downstream pits 24 are inserted and immersed in the molten glass G inside. By adopting such a configuration, there is no need to immerse the riser pipe 16 and the downfall pipe 18 made of electroformed brick directly in the molten glass G, and the durability against the molten glass G in the upstream pit 20 and the downstream pit 24 is improved. This can greatly improve the above problem.
[0024]
Specifically, as shown in FIG. 2, an extension pipe 26 made of platinum or a platinum alloy is provided in communication with the lower end portion of the ascending pipe 16. Since the extension pipe 26 on the ascending pipe 16 side and the extension pipe 28 on the downfall pipe 18 side are configured identically, only the extension pipe 26 on the uprising pipe 16 side will be described, and the extension pipe 28 on the downfall pipe 18 side will be described. Description is omitted.
[0025]
The extension pipe 26 has a cylindrical cylindrical body 26a, a fixing flange 26b formed at one end of the cylindrical body 26a, and a sealing flange 26c formed at a predetermined distance from the fixing flange 26b. A tube made of platinum or a platinum alloy. What is necessary is just to comprise the internal diameter of the cylinder 26a in the magnitude | size substantially equivalent to the internal diameter of the raising pipe | tube 16 so that it may communicate with the raising pipe | tube 16 smoothly.
[0026]
The fixing flange 26 b is formed so that the upper end thereof can be fixed to the rising pipe 16 by being inserted between the electroformed bricks 30, 30 constituting the rising pipe 16, that is, a joint.
The extension pipe 26 may be fixed to the ascending pipe 16 by various methods without being limited to the fixing flange 26b, but is preferably fixed using the fixing flange 26b. That is, when the fixing flange 26b is not provided at the upper end of the cylindrical body 26a, the molten glass G enters between the outer side of the cylindrical body 26a and the electroformed brick 30, and the insulating brick 32 and the insulating material 38 are eroded. The heat conductivity in the vicinity of the bottom surface of the housing leg 12a increases and the temperature of the outer wall surface of the housing rises and the housing may be deformed. However, by forming the fixing flange 26b at the upper end of the cylindrical body 26a, The problem is solved. Thereby, the temperature rise of the housing leg part 12a and the downward distortion accompanying this are prevented, and the molten glass G caused by the misalignment or loosening of the joints of the electroformed brick 30 and the heat insulating brick 32 in the housing leg part 12a. Leakage, and thus an excessive temperature rise of the housing leg 12a can be prevented.
Therefore, it is also possible to prevent the temperature from increasing due to the partial temperature increase, and the thermal stress deformation of the entire apparatus and the increase in leakage of the molten glass G.
[0027]
On the other hand, the sealing flange 26c closes the lower end of the housing leg 12a from the outside together with a seal member 34, which will be described later, when the extension pipe 26 is provided at the lower end of the downcomer pipe 18. It is for securing. Alternatively, the extension flange 26 made of platinum or a platinum alloy may be self-heated and held at an appropriate temperature using the sealing flange 26c as an electrode. The mechanism for ensuring airtightness at the lower end of the housing leg 12a is not limited to the method using the sealing flange 26c, and various mechanisms can be used.
As described above, the extension pipe 26 is preferably fixed to the ascending pipe 16 by the fixing flange 26b. However, the sealing flange 26c is also used to carry the vacuum seal and the weight of the extension pipe 26 so as to be fixed. The flange 26b may be limited to the role of preventing the outer surface of the extension pipe from being separated from the inner surface of the brick in the passage surrounded by the electroformed brick 30a. In this case, the fixing flange 26b is provided in the horizontal direction of the extension pipe 26. In addition to playing a role of preventing minute eccentricity, it also plays a role of preventing the molten glass G from entering between the outer surface of the extension pipe and the inner surface of the brick.
[0028]
The composition of platinum or a platinum alloy used for such extension tubes 26 and 28 is not particularly limited, but is a platinum alloy containing 70 wt% to 98 wt% platinum and 2 wt% or more of Rh. Is preferable in that the high-temperature strength is particularly excellent.
[0029]
The extension pipe 26 configured as described above has the fixing flange 26b inserted and sandwiched in the joint portion between the electroformed bricks 30 near the lower end of the rising pipe 16, and the sealing flange 26c, the decompression housing 12, and the like. In between, the sealing member 34 is arrange | positioned and the airtightness in the lower end of the housing leg part 12a is ensured. The seal member 34 is not particularly limited as long as it has airtightness and heat resistance, and the inside of the housing 12 may be reduced to 1/20 atm at most, so that a normal vacuum seal used in a vacuum apparatus is used. A heat-resistant material may be selected from the materials.
[0030]
By the way, as described above, the extension pipe 26 has the fixing flange 26b sandwiched between the joints of the electroformed brick 30. The clamping force at this time is secured by the weight of the electroformed brick 30. Accordingly, when there are few electroformed bricks 30 loaded on the fixing flange 26b, the joints open with the expansion and contraction of the molten glass G, and the clamping force decreases, and the fixing flange 26b is sufficiently clamped. The molten glass G may leak out.
For this reason, as shown in FIG. 2, a reinforcing member 36 may be provided above the extension pipe 26 to reinforce the clamping force of the fixing flange 26 b by the electroformed brick 30. The reinforcing member 36 may be any member that can press the electroformed brick 30 above the fixing flange 26b downward, and the material and structure thereof are not particularly limited. For example, when the electroformed brick 30 is highly stacked on the fixing flange 26b, the fixing flange 26b can be firmly held by its own weight without the reinforcing member 36.
[0031]
Further, as shown in FIG. 2, the electroformed brick 30a provided at the lowermost end in the housing leg 12a is an inner portion facing the extension pipe 26, and is a bottom facing the bottom surface of the housing leg 12a. It is preferable that the side corner portion is formed by being cut out along the circumference, and the heat insulating material 38 is disposed in the cutout portion. That is, in the bottom surface of the housing leg portion 12a, the vicinity of the extension pipe 26 is most easily heated, so that the temperature rises excessively, causing distortion and deformation, and to the insulating brick layer 32 of the molten glass G from the joint. May cause leakage. For this reason, by disposing the heat insulating material 38 in the vicinity of the extension pipe 26, an excessive temperature rise at the bottom surface of the housing leg 12a can be prevented, and the durability at this portion can be further improved. Further, since the heat insulating material 38 is disposed only in the lower part of the electroformed brick 30a, it is possible to secure sufficient strength in the upper part of the electroformed brick 30a and firmly hold the fixing flange 26b. it can.
The heat insulating material 38 is not particularly limited as long as it has a higher heat insulating property than the electroformed brick 30.
[0032]
In this way, the lower end portion of the ascending pipe 16 that is immersed in the molten glass G in the upstream pit 22, and the lower end portion of the descending pipe 18 that is immersed in the molten glass G in the downstream pit 24 By forming with platinum or a platinum alloy, deterioration and breakage of the lower end of the riser 16 and the lower end of the downcomer 18 can be prevented, and sufficient durability for the molten glass G can be secured.
[0033]
By the way, it is preferable that the housing leg 12a is provided with a buffering mechanism 40 so that the housing leg 12a can be expanded and contracted in accordance with thermal expansion and contraction in the vertical direction of the electroformed brick 30 and the heat insulating brick 32. By doing so, when the electroformed brick 30 constituting the riser pipe 16 and the surrounding heat insulating brick 32 are thermally expanded, the buffer mechanism 40 can absorb the thermal expansion of the riser pipe 16, while When the brick is contracted, the housing leg 12a is contracted so as to follow the contraction, thereby preventing the joint from opening due to the contraction and effectively preventing the molten glass G from leaking. Therefore, it is possible to prevent damage to the decompression housing 12 and a reduction in the degree of decompression associated therewith, thereby improving the durability and safety of the apparatus.
[0034]
Specifically, as shown in FIG. 2, the buffer mechanism 40 includes a cylindrical bellows 42 and a push-up means 44. In the cylindrical bellows 42, the housing leg 12a is cut and separated in the horizontal direction, and the upper part (hereinafter referred to as the upper part 13a) and the lower part (hereinafter referred to as the lower part) of the once separated housing leg 12a. And a side portion 13b) are connected in an airtight and extendable manner. The material of the cylindrical bellows 42 is not particularly limited, but is preferably made of metal, particularly stainless steel, like the decompression housing 12.
[0035]
The push-up means 44 is not particularly limited as long as it can urge the lower portion 13b of the housing leg 12a upward, and various mechanisms can be employed. For example, as shown in FIG. 2, two connecting members 46 and 48 that are fixed to the upper side portion 13 a and the lower side portion 13 b in pairs, and a lower end is fixed to the lower connecting member 48, If it comprises a bar 50 provided so as to be inserted through the passage hole of the upper connecting member 46, and a biasing member 52 that connects both the connecting members 46 and 48 and biases the lower portion 13b upward. Good. The urging member 52 is not particularly limited, but a coil spring is preferably exemplified. By configuring in this way, the thermal expansion of the electroformed brick 30 and the heat insulating brick 32 can be released downward against the urging force of the urging member 52, and distortion and damage of the device due to the thermal expansion can be prevented. Thus, the safety of the device can be increased. Moreover, even if the electroformed brick 30 and the heat insulating brick 32 contract, the lower side portion 13b can be followed to prevent the joint from opening. Such push-up means 44 is preferably provided at a plurality of locations with respect to one cylindrical bellows 42.
Further, the lower end portion of the housing leg 12a may be reinforced with a rib or the like.
[0036]
An example of a process in which the molten glass G is defoamed with the vacuum degassing apparatus 10 of the present invention and continuously supplied to the next processing furnace will be described below.
First, the inside of the decompression housing 12 and the inside of the decompression deaeration 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 upstream pit 22 through the extension pipe 26 and the rising pipe 16 and is guided into the vacuum degassing tank 14, and the molten glass G is vacuum degassed. Defoaming is performed in the tank 14 under reduced pressure conditions. The defoamed molten glass G is guided to the downstream pit 24 through the downcomer pipe 18 and the extension pipe 28.
[0037]
As mentioned above, although the vacuum degassing apparatus of the molten glass of this invention was demonstrated in detail, this invention is not limited to the said Example, You may perform various improvement and change in the range which does not deviate from the summary of this invention. Of course.
[0038]
【The invention's effect】
As described above in detail, according to the present invention, in a vacuum degassing apparatus for molten glass that removes bubbles from continuously supplied molten glass, sufficient durability against high-temperature molten glass is achieved. While securing the cost, the cost can be greatly reduced, and as a result, the capacity of the apparatus can be increased and the temperature of the vacuum degassing treatment can be increased. Therefore, it is very suitable for the use which performs the depressurization process of the molten glass of a large flow rate with high efficiency.
[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 connecting portion between an ascending pipe and an extension pipe in the vacuum degassing apparatus shown in FIG.
FIG. 3 is a schematic cross-sectional view showing an example of a conventional vacuum degassing apparatus.
[Explanation of symbols]
10 Vacuum Degassing Device 12 (for Molten Glass) Vacuum Housing
12a, 12b Housing leg
13a Upper side
13b lower portion 14 the vacuum degassing vessel 16 riser 18 downcomer 20 dissolving tank 22 upstream pit 24 downstream pin Tsu preparative 26,28 extension pipe 26a cylinder 26b fixing flanges 26c sealing flanges 30, 30a electrocast brick 32 insulation Brick 34 Seal member 36 Reinforcing member 38 Heat insulating material 40 Buffer mechanism 42 Cylindrical bellows 44 Pushing means 46, 48 Connecting means 50 Bar material 52 Biasing member
100 Vacuum degassing equipment
102 decompression housing
104 vacuum degassing tank
106 Rise pipe
108 downcomer
110 Insulation
112 Dissolution tank

Claims (2)

A vacuum housing that is vacuumed;
A vacuum degassing tank that is provided in the vacuum housing and performs vacuum degassing of the molten glass;
A riser pipe which is provided in communication with the vacuum degassing tank and raises the molten glass before the vacuum degassing and introduces it into the vacuum degassing tank;
A downcomer pipe which is provided in communication with the vacuum degassing tank, and descends the molten glass after the vacuum degassing from the vacuum degassing tank;
An extension pipe provided in communication with the lower ends of the ascending pipe and the descending pipe,
The ascending pipe, the vacuum degassing tank, and the downcomer pipe are formed of an electroformed brick at least at a portion that directly contacts the molten glass,
The extension tube is made of platinum or a platinum alloy, and has a cylindrical tube, a fixing flange formed at one end of the tube, and a seal formed at a predetermined distance from the fixing flange. And a flange for
The extension pipe is fixed to the ascending pipe or the descending pipe by inserting and sandwiching the fixing flange into the joint of the electroformed brick forming the ascending pipe or the descending pipe,
A vacuum degassing apparatus for molten glass, wherein a sealing member is disposed between the sealing flange and the vacuum housing .   Furthermore, the reinforcement member which reinforces the clamping force by the said electrocast brick of the said fixing flange is provided, The vacuum degassing apparatus of the molten glass of Claim 1 characterized by the above-mentioned.

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