JP6431394B2 - Stirrer for glass production - Google Patents

Description

  The present invention relates to a stirrer for glass production for stirring and homogenizing molten glass. Specifically, the present invention relates to a stirrer for glass production that can stir molten glass with high efficiency and is excellent in durability.

  In the manufacturing process of various glass products, the glass material that has been adjusted and mixed is melted, and the glass in the molten state is homogenized and the refractive index is homogenized by stirring the molten glass, and then molded into glass. It is a product. This stirring step is a particularly important step in the glass production process under the circumstances where a glass product that is homogeneous and free of defects (such as striae and bubbles) is desired.

  Stirring of molten glass is performed by inserting and rotating a stirrer for glass production into a molten glass tank. A stirrer for glass production is configured by installing a stirrer blade (hereinafter sometimes simply referred to as a blade) as a stirring blade on a stirrer shaft (hereinafter simply referred to as a shaft) that serves as a rotating shaft. For example, Patent Document 1 describes a glass production stirrer in which a rod-like blade is fixed to a stirrer shaft by penetrating it and installed in multiple stages. Further, Patent Document 2 describes a glass production stirrer in which two sets of rod-shaped blades protruding on both sides around a stirrer shaft are fixed so as to intersect.

JP-A-7-223823 JP 2004-149338 A

  The performance preferentially required for the stirrer for glass production is to exhibit an effective stirring action so that a suitable flow state can be imparted to the molten glass to achieve homogenization. In recent years, glasses with various properties have been developed to meet various applications and requirements. Among them, many glasses have a high viscosity in the molten state, and it is required to arrange a blade so that an effective stirring action can be exerted even on such a high-viscosity molten glass.

  Moreover, durability as equipment is also required for a glass production stirrer. Molten glass is a fluid having a high temperature of 1000 ° C. or higher, and a glass production stirrer for treating the molten glass is exposed to a severe use environment. In particular, the load applied to the blade is considerably large, and there is a concern about durability due to the high viscosity of the molten glass.

  The above-mentioned problems of strengthening the stirring action and ensuring the durability are considered in the glass manufacturing stirrers known so far, but it can be said that there is still room for improvement. Then, this invention aims at providing the stirrer for glass manufacture which is excellent in durability and cannot produce a breakage easily, exhibiting the stirring effect | action of an efficient molten glass.

  The present invention for solving the above-mentioned problems is a glass production stirrer comprising a hollow pipe-shaped stirrer shaft and at least two stirrer blades fixed through the stirrer shaft, wherein the at least two stirrers are provided. At least one stirrer blade of the blade passes through the stirrer shaft in a divided state, and the at least two stirrer blades are fixed so as to intersect near the center line of the stirrer shaft, A stirrer for glass production, characterized in that the stirrer shaft includes a socket that has an outer shape in which at least two cylindrical bodies intersect each other and surrounds the stirrer blade inside the stirrer shaft.

  In order to increase the stirring action, it can be said that the number of blades and the surface area can be increased. In the above prior art, like the stirrer described in Patent Document 2, a plurality of blades that protrude from the shaft and intersect with each other have a high stirring action.

  However, when manufacturing such a stirrer, the blades cannot be crossed or penetrated at the same height position. For this reason, it has been common to divide the blades and bring them into contact with the outer surface of the shaft and join them by butt welding. However, butt welding is a joint structure that is originally inferior in fixing strength. Further, the heat affected zone formed by welding generally has a reduced strength. In particular, when strengthened platinum or the like which is an oxide dispersion strengthened material is applied, the degree of strength reduction increases because the particle dispersed structure which is a strengthened structure disappears by melting and solidifying during welding. The root of the blade is a portion where stress is concentrated during agitation. As described above, there is a concern that the stress concentration on the butt portion where the fixing strength is uneasy due to the structure may break. Therefore, if priority is given to strength and durability, it is preferable to fix the blade in a state where the shaft is penetrated.

  Therefore, according to the present invention, a part or all of the blades are divided and passed through the shaft, thereby eliminating the mutual interference of the blades and crossing them. However, in this state, the ends of the divided blades are in a free state, so that the fixing is insufficient. Therefore, by setting a socket for holding the intersecting blade inside the shaft, a plurality of intersecting blades are integrated to stabilize the shaft. Hereinafter, the stirrer for glass production according to the present invention will be described in more detail.

  In this invention, it has the characteristics in the structure of the socket installed in the shaft, and the arrangement | positioning relationship of a braid | blade. As these aspects, the socket has an outer shape in which at least two cylinders intersect and communicate with each other at the intersection. And the blade | wing of a cross | intersection state can be formed by inserting and hold | maintaining the stirrer blade divided | segmented from each both ends of the cylinder which comprises this socket. FIG. 1 is a specific example of a socket, and a blade can be inserted into the opening of the socket to form a crossed blade (FIG. 2).

  Moreover, when using the socket of this aspect, each blade can be fixed uniformly by notching the tip part of the divided stirrer blade to form a processed surface. As shown in FIG. 3, a split blade having a machining surface is inserted, and the machining surfaces of the respective stirrer blades are crossed in the vicinity of the intersecting portion of the socket, so that a constraining force by the socket is added and an integral blade is formed. Is done.

  Regarding the blade division, all the blades may be divided as described above (FIG. 3), but one blade without division can be partially used. At this time, one stirrer blade is inserted and held through one of the cylindrical bodies of the socket, and the divided stirrer blade is inserted and held from both ends of the other cylindrical body ( FIG. 4).

  Further, regarding the configuration of the socket, while having an outer shape in which at least two cylinders intersect each other, the first cylinder that penetrates and the first cylinder that protrudes from the first cylinder, Some include at least one set of second cylinders having partitions at the boundary (FIG. 5). When this socket is applied, a single stirrer blade can be passed through and held in the first cylinder, and the stirrer blade divided into the second cylinder can be inserted and held (FIG. 6).

  Furthermore, the present invention can provide a belt-shaped reinforcing ring that is in contact with the inner wall surface of the stirrer shaft and has a through hole at a position corresponding to the end of the cylindrical body of the socket. With this reinforcing ring, the blade can be more stably fixed (FIG. 7).

  The stirrer for producing glass according to the present invention is characterized in that the socket and the reinforcing ring described above are provided inside the shaft, whereby the blades are appropriately arranged, and other configurations are the same as those of the conventional stirrer. .

  The constituent material of the blade is preferably a platinum-based material such as platinum, platinum alloy, reinforced platinum, or reinforced platinum alloy. This is because it is preferable to apply a high-melting-point material excellent in chemical stability in order to process a high-melting-point molten glass. Examples of the platinum-based material include a platinum-rhodium alloy (for example, platinum-5 to 30% by weight rhodium alloy) or a platinum-gold alloy (for example, platinum-5% by weight gold alloy) as pure platinum or a platinum alloy.

  In addition, application of reinforced platinum or reinforced platinum alloy is also preferable as the platinum-based material. The reinforced platinum or reinforced platinum alloy is a dispersion strengthened alloy in which a metal oxide is dispersed in platinum or a platinum alloy. This reinforced platinum or reinforced platinum alloy is more suitable as a structural material for a glass manufacturing apparatus used in a high temperature environment because it has excellent high temperature strength characteristics, particularly high temperature creep strength. Preferred dispersed particles of reinforced platinum or reinforced platinum alloy are refractory valve metal oxides such as zirconium oxide and yttrium oxide, and rare earth metal oxides such as samarium oxide. The dispersed particles preferably have a particle size of less than 1 μm, particularly about several tens of nanometers, and the amount of the dispersed particles is preferably several weight% or less. The matrix may be platinum or platinum-rhodium alloy (for example, platinum-5 to 30% by weight rhodium alloy) or platinum-gold alloy (for example, platinum-5% by weight gold alloy) as platinum alloy. preferable.

  The configuration of the blade is preferably a rod-shaped configuration, and a hollow pipe-shaped configuration is preferable in consideration of light weight and material cost. The blade is a hollow cylindrical body formed by winding a flat plate made of the above-mentioned platinum-based material and seam-welding two opposing sides, and a circular cylinder formed by welding the disk made of the same material to both ends of the cylinder. Often served as. In this case, the plate thickness is preferably 1.5 mm or more.

  The constituent material of the socket is preferably platinum, platinum alloy, reinforced platinum, or reinforced platinum alloy. The same applies to the reinforcing ring. The constituent material of the shaft that functions as the rotating shaft of the blade is preferably a platinum-based material (platinum, platinum alloy, reinforced platinum, reinforced platinum alloy) as in the case of the blade.

  When a cylindrically shaped stirrer blade is used, the ratio (Db / Ds) between the diameter (Db) and the diameter (Ds) of the stirrer shaft is preferably 1/3 or less. When Db / Ds exceeds 1/3 (when the blade diameter is large), there is a danger that the diameter of the hole in the shaft increases and the strength of the shaft decreases. Further, since the insertion length of the blade into the socket cannot be obtained sufficiently, it is preferable to add a restriction. The lower limit of Db / Ds does not need to be set specifically, but is preferably 1/10 from a practical viewpoint such as a stirring action.

  The number of blades is not limited. It is not limited to what the two blades penetrating the shaft intersect so far. A stirrer having three or more blades penetrated (FIG. 8). It is preferable that 2 to 4 blades cross each other. Further, the blade may penetrate horizontally with respect to the shaft, but may be inclined. Further, the crossing angle between the blades is not limited.

  The blade is preferably provided in a plurality of stages. That is, it is preferable that at least two stirrer blades intersecting on a substantially center line of the stirrer shaft are one set of blade groups and one or more sets of blade groups are fixed to the stirrer shaft in multiple stages. The number of stages is preferably 2 to 10 stages. In one stage, the stirring action is weak, and those exceeding 10 stages are excluded from the viewpoint of material cost. The number of stages is set in consideration of the size (depth) of the stirring tank.

  The blade passing through the shaft is preferably welded at the base portion of the shaft. This is to provide a seal that prevents the molten glass from entering the shaft. Welding also has the effect of complementarily fixing the blade. However, since the heat-affected zone formed by welding as described above is in an unfavorable state in terms of strength, the welding of the blade is sufficient for welding the blade so as to seal the gap with the shaft.

  As described above, the glass production stirrer according to the present invention has an optimal balance between the arrangement state of the blade and the fixed strength, and various conventional stirrers are used when stirring high-viscosity molten glass. In addition to having a higher stirring action, durability is also ensured.

The figure explaining an example of the socket for blade fixation used by this invention. The figure explaining an example of the braid | blade fixing by a socket. The figure explaining an example of the braid | blade fixing (tip part process) by a socket. The figure explaining the example of the braid | blade fixing which uses one braid | blade for some. The figure explaining the other structural example of a socket. The figure explaining the example of the blade fixation by the socket of FIG. The figure explaining the example of application of a reinforcement ring. The figure explaining the structure of the socket which fixes three penetration blades. The external appearance of the stirrer for glass manufacture manufactured by this embodiment. The stress-rupture time diagram for calculating the life of the stirrer concerning this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described. FIG. 9 is an external view of the stirrer for glass production produced in the present embodiment. This stirrer for glass production is one in which two rod-shaped blades orthogonal to each other are set on a stirrer shaft made of a hollow pipe.

  The blade is a pipe manufactured by winding a reinforced platinum alloy plate having a thickness of 1.5 mm and seam welding the butt portion (thickness 1.5 mm, diameter 20 mm, length 200 mm). This reinforced platinum is platinum in which zirconium oxide is dispersed using a platinum-10% rhodium alloy (trade name: nanoplat (registered trademark), manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) as a matrix. The stirrer shaft is made of the same reinforced platinum hollow pipe (thickness 2.0 mm, diameter 60 mm, length 500 mm). A hole (diameter 21 mm) for penetrating the blade is drilled in the shaft.

  For fixing the blade to the shaft, a socket having the same structure as the socket of FIG. 5 is applied. The blade was fixed in such a manner that the socket opening and the shaft hole were aligned with each other, and after the socket was built in the shaft, the blades were sequentially inserted and connected (FIG. 6). Then, the base of the blade joint portion on the outer surface of the shaft was joined by seam welding. At this time, with respect to the cross section of the blade in the welded portion, the heat input was adjusted so that the depth of the heat affected zone was 1.2 mm or less. The interval between the lower blade and the upper blade is 150 mm.

  About the stirrer which concerns on this embodiment, the simulation about molten glass stirring was performed and the stirring effect | action was confirmed. For the simulation, commercially available simulation software (trade name: ANSYS CFD, manufactured by Ansys Japan) was used. This simulation is to analyze the Mises stress distribution in the stirrer when one stirrer is installed in the stirring tank and the molten glass flow is stirred. The simulation conditions were a molten glass flow temperature: 1400 ° C., a glass viscosity of 100 Pa · s, and a stirrer rotation speed of 20 rpm.

  Moreover, this simulation was performed also about the stirrer (patent document 2) which manufactured the braid | blade by butt welding as a comparative example. The stirrer for comparison has the same external shape and dimensions as the stirrer according to this embodiment. And the maximum Mises stress was calculated based on the simulation result about both stirrers. In the result of this simulation, it was confirmed that the maximum stress was applied to the root portion of the blade, and the maximum Mises stress was 1.6 MPa in the present embodiment and 2.7 MPa in the comparative example. This analysis result shows that the generated stress was reduced by 40% by using the blade in the penetrating structure while using the socket.

  Next, from the calculated maximum Mises stress, the time (life) until the material breakage of the stirrer was obtained. As shown in FIG. 10, the life of each stirrer was referred to based on the high temperature creep curve (stress-rupture time diagram) for the reinforced platinum alloy applied in the present embodiment. As a result, assuming that the life of the comparative example is 1 year, the life of the stirrer of this embodiment is about 9 years, and it has been found that there is a significant effect of improving the life.

  The stirrer for producing a glass according to the present invention has a high stirring action even when stirring a high-viscosity molten glass and has excellent durability. The invention can be used in particular for the production of glass panes for LCDs, OLEDs or plasma displays, and for the homogenization of glass melts in glass products such as glass ceramics, borosilicate glasses, optical glasses, glass tubes.

Claims (9)

In a glass production stirrer comprising a hollow pipe-shaped stirrer shaft and at least two stirrer blades that are fixed through the stirrer shaft,
At least one stirrer blade of the at least two stirrer blades penetrates the stirrer shaft in a divided state;
The at least two stirrer blades are fixed so as to intersect near the center line of the stirrer shaft;
A stirrer for producing glass, characterized in that the stirrer shaft includes a socket that has an outer shape in which at least two cylindrical bodies intersect each other and holds a stirrer blade inside the stirrer shaft while surrounding the stirrer shaft. The socket has an outer shape in which at least two cylinders intersect with each other, and the cylinders communicate with each other at the intersections;
The stirrer for glass manufacture according to claim 1, wherein a stirrer blade divided from both ends of each of the cylindrical bodies is inserted and held. At the tip of the divided stirrer blade, a cut surface is formed by cutting,
The stirrer for glass production according to claim 2, wherein the processed surfaces of the respective stirrer blades are engaged with each other and intersect each other in the vicinity of the intersecting portion of the socket. The socket has an outer shape in which at least two cylinders intersect with each other, and the cylinders communicate with each other at the intersections;
Insert and hold one stirrer blade for any of the cylinders,
The stirrer for glass production according to claim 1, wherein the divided stirrer blades are inserted and held from both ends for the other cylindrical bodies. The socket has an outer shape in which at least two cylinders intersect,
A first cylindrical body penetrating, and at least one set of second cylindrical bodies projecting from the first cylindrical body and having a partition at the boundary with the first cylindrical body,
A first stirrer blade is passed through and held in the first cylinder,
The stirrer for glass production according to claim 1, wherein a divided stirrer blade is inserted and held in the second cylindrical body.   The stirrer for manufacturing a glass according to any one of claims 1 to 5, further comprising a belt-shaped reinforcing ring that is in contact with the inner wall surface of the stirrer shaft and has a through hole at a position corresponding to the end of the cylindrical body of the socket. . A set of at least two stirrer blades intersecting substantially on the center line of the stirrer shaft,
The stirrer for glass production according to any one of claims 1 to 6, wherein one or more sets of blade groups are fixed to the stirrer shaft in multiple stages.   The stirrer for glass manufacture according to any one of claims 1 to 7, wherein a ratio (Db / Ds) of a diameter (Db) of the stirrer blade to a diameter (Ds) of the stirrer shaft is 1/3 or less.   The stirrer blade for glass production according to any one of claims 1 to 8, wherein the stirrer blade is made of a platinum-based material.

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