JP2024085600A - Agitation device, stirrer, and method for manufacturing glass article - Google Patents

Abstract

The mixing performance of a mixing device is improved.
[Solution] The molten glass stirring device includes a stirrer having a shaft and a plurality of stirring blades arranged along the longitudinal direction of the shaft, a stirring tank that houses the stirrer, and a rotating device that rotates the stirrer. The stirring blades are rod-shaped, and adjacent stirring blades in the longitudinal direction of the shaft have a phase difference. The stirrer includes a connecting portion that connects two adjacent stirring blades of the plurality of stirring blades.
[Selected figure] Figure 2

Description

The present invention relates to a stirring device for stirring molten glass, a stirrer for use in the stirring device, and a method for manufacturing a glass article.

As is well known, in the manufacturing process of glass sheets, a stirring process is carried out in which the molten glass that is the source of the glass sheets is stirred and homogenized in a cylindrical stirring tank. A stirrer is used to carry out the stirring process. The stirrer stirs the molten glass as it flows inside the stirring tank in the longitudinal direction of the axis.

For example, Patent Document 1 discloses a stirrer that includes a shaft that extends in the vertical direction and multiple impellers attached along the longitudinal direction of the shaft, and that rotates the multiple impellers around the shaft as the shaft rotates to stir the molten glass in a stirring tank.

Each impeller of this stirrer is configured in a plate shape. The impellers are attached to the shaft so that when rotating around the shaft, the impellers at the upper end of the shaft are delayed in phase around the shaft relative to the impellers at the lower end. In addition, in this stirrer, an intervening portion is interposed between the adjacent impellers in at least one of the multiple pairs of adjacent impellers (see claim 1 and paragraph 0041 of the same document).

JP 2018-104212 A

As a result of extensive research, the inventors discovered that the mixing performance of the mixing device can be improved by improving the shape of the plate-shaped mixing blades in the stirrer.

The technical objective of the present invention is to improve the stirring performance of molten glass in a stirring device.

(1) The present invention is intended to solve the above problems, and is a molten glass stirring device comprising a stirrer having a shaft extending in the vertical direction and a plurality of stirring blades arranged along the longitudinal direction of the shaft, a stirring tank that houses the stirrer, and a rotating device that rotates the stirrer, wherein the stirring blades are rod-shaped, adjacent stirring blades in the longitudinal direction of the shaft have a phase difference, and the stirrer comprises a connecting portion that connects two adjacent stirring blades among the plurality of stirring blades.

With this configuration, the stirring blades are configured in a rod shape, and two adjacent stirring blades are connected by a connecting part, making it possible to improve the stirring capacity of the stirring device.

(2) In the configuration described in (1) above, the stirring blade may include a tip blade provided at the tip of the stirring blade. This can further improve the stirring ability of the stirring tank for the molten glass.

(3) In the configuration described in (1) or (2) above, the tip wing may be rod-shaped extending in the vertical direction and have an upper end and a lower end, and the connecting portion may be connected to the upper end or the lower end of the tip wing.

With this configuration, the stirring blade and the connecting part are connected via the tip blade, which improves the strength of the stirring blade. In addition, by constructing the tip blade and the connecting part as one unit, it becomes possible to easily manufacture the stirrer.

(4) In any of the configurations described in (1) to (3) above, the agitator blade may have a corner in cross section, and the corner may be configured to face forward in the rotation direction of the agitator blade.

This configuration makes it possible to reduce the torque acting on the shaft while maintaining a high stirring force for the molten glass in the stirring tank.

(5) In any of the configurations (1) to (4) above, the stirrer may have a non-connected region in which the connecting portion is not formed between two adjacent stirring blades among the plurality of stirring blades.

This configuration makes it possible to create a difference between the flow rate of the swirling flow of molten glass stirred by the stirring blade with the connecting portion and the flow rate of the swirling flow of molten glass in the stirring blade with the non-connecting region. This difference in flow rate makes it possible to stir the molten glass more effectively.

(6) In the configuration described in (5) above, the stirring tank may include an inlet through which the molten glass flows and an outlet provided below the inlet and through which the molten glass flows out, the connecting portion may be located at the height of the inlet and the outlet, and the non-connecting region may be located between the inlet and the outlet.

With this configuration, the connecting portion is disposed at the height of the inlet and outlet, and the non-connecting area is disposed between the inlet and outlet, so that the molten glass can be stirred more effectively.

(7) The present invention is intended to solve the above problems, and is a stirrer having a shaft extending in the vertical direction and a plurality of stirring blades arranged and attached along the longitudinal direction of the shaft, the stirring blades being rod-shaped, two adjacent stirring blades in the longitudinal direction of the shaft having a phase difference, and the stirrer being characterized in that it has a connecting portion that connects two adjacent stirring blades among the plurality of stirring blades.

With this configuration, the stirring blades are configured in a rod shape, and two adjacent stirring blades are connected by a connecting part, making it possible to improve the stirring capacity of the stirring device.

(8) The method for manufacturing a glass article according to the present invention is intended to solve the above problems, and is characterized by including a stirring step of stirring the molten glass in the stirring tank using the stirring device described in any one of (1) to (6) above. According to this configuration, by using the stirring device in the stirring step, the molten glass can be effectively stirred in the stirring step.

The present invention can improve the mixing performance of a mixing device.

FIG. 2 is a side view showing the manufacturing apparatus for a glass article. FIG. 2 is a cross-sectional view showing the internal structure of the stirring device. FIG. FIG. 2 is a cross-sectional view of a stirring blade of a stirrer. FIG. 2 is a perspective view of a stirrer according to Comparative Example 1. FIG. 11 is a side view of a stirrer according to Comparative Example 2.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figs. 1 to 4 show one embodiment of a method for manufacturing a glass article and a stirring device according to the present invention. In this embodiment, a case where a glass plate is manufactured as an example of a glass article will be described, but the form of the glass article is not limited to this embodiment.

As shown in FIG. 1, the manufacturing apparatus 1 used in this method is equipped with a supply path 5 that supplies molten glass from a melting furnace 2 located at the upstream end and a fining chamber 3 connected to the downstream side of the melting furnace 2 to a forming device 4 located at the downstream end.

The supply path 5 includes a stirrer 6 that stirs the molten glass flowing out of the fining chamber 3, and a pot 7 that is connected downstream and adjusts the viscosity and flow rate of the molten glass. The fining chamber 3 and the stirrer 6, the stirrer 6 and the pot 7, and the pot 7 and the forming device 4 are connected by circulation pipes 8 to 10 that circulate the molten glass. In the circulation pipe 9, the pot 7, and the circulation pipe 10 between the stirrer 6 and the forming device 4, a process is carried out to adjust the viscosity of the molten glass to a value suitable for forming. Specifically, a process is carried out to increase the viscosity of the molten glass by lowering the temperature of the molten glass.

The forming device 4 is a device that continuously forms a glass ribbon, which is the base of a glass plate, from the molten glass supplied through the fining chamber 3, the stirring device 6, and the pot 7. For example, a device that performs forming by the overflow downdraw method, a device that performs forming by the slot downdraw method, etc. are used as the forming device 4. The formed glass ribbon is cut to cut out a glass plate. The cut out glass plate is subjected to processes such as cutting, edge processing, cleaning, inspection, and packaging as necessary to produce a glass plate. The manufactured glass plate is used, for example, as a substrate or cover glass for various displays. In addition, a glass roll as a glass article is manufactured by cutting and removing both ends in the width direction of the formed glass ribbon and then winding the glass ribbon. The forming device 4 may be a device that forms a glass article other than a glass plate, and may be, for example, a device that continuously forms a glass tube or a glass rod from molten glass by the Danner method.

The configuration of the stirring device 6 is described in detail below.

As shown in FIG. 2, the stirring device 6 includes a stirring tank 6a formed in a cylindrical shape with a cylindrical center line extending in the vertical direction, and a stirrer 11 housed inside the stirring tank 6a. The surface of the inner wall 12 of the stirring tank 6a is made of platinum (including reinforced platinum) or a platinum alloy (including reinforced platinum alloy). The stirring tank 6a is configured to be electrically heated to adjust the temperature of the molten glass.

At the top of the stirring tank 6a, an inlet 13 is formed to allow the molten glass to flow into the stirring tank 6a. At the bottom of the stirring tank 6a, an outlet 14 is formed to allow the molten glass stirred by the stirrer 11 to flow out of the stirring tank 6a.

The inlet 13 of the stirring tank 6a is connected to the flow pipe 8 that connects the clarification chamber 3 and the stirring tank 6a. The outlet 14 of the stirring tank 6a is located below the inlet 13 and is connected to the flow pipe 9 that connects the stirring tank 6a and the pot 7.

As shown in Figures 2 and 3, the stirrer 11 comprises a shaft 15 and a number of stirring blades 16a-16f attached to the shaft 15 so as to be aligned along the longitudinal direction of the shaft 15. The surfaces of the shaft 15 and each of the stirring blades 16a-16f are made of platinum or a platinum alloy. The stirrer 11 is configured to stir the molten glass in the stirring tank 6a by rotating the multiple stirring blades 16a-16f around the shaft 15 as the shaft 15 rotates. The number of rod-shaped stirring blades provided on the stirrer 11 can be, for example, 4 to 16, and is preferably 4 to 7.

The shaft 15 is configured as a round bar extending in the vertical direction. A rotating device (e.g., a motor as a drive source) that rotates the stirrer 11 is connected to the upper end of the shaft 15. With the operation of this rotating device, the shaft 15 rotates in the direction indicated by the arrow R in Figures 2 and 3 (clockwise direction in a plan view). Not limited to this, the shaft 15 can also rotate in the direction opposite to the rotation direction R. Note that the lower end of the shaft 15 is a free end, unlike the upper end.

The multiple agitator blades 16a-16f are arranged at equal intervals along the longitudinal direction of the shaft 15. Not limited to this, the multiple agitator blades 16a-16f may be provided on the shaft 15 at different intervals. In this embodiment, six agitator blades 16a-16f are formed on the shaft 15. Hereinafter, the agitator blades 16a-16f are referred to as the first agitator blade 16a to the sixth agitator blade 16f from the top. The agitator blades 16a-16f have the same shape and dimensions, but blades of different shapes and dimensions may also be used.

The multiple agitator blades 16a to 16f are attached to the shaft 15 so that when rotating around the shaft 15, the agitator blades on the upper end of the shaft 15 have a phase lead around the shaft 15 relative to the agitator blades on the lower end.

In more detail, between two adjacent agitating blades, the relatively upper agitating blade is designed to have a phase lead around the shaft 15 by an angle θa (see Figure 3) with respect to the relatively lower agitating blade. Note that the phase is sequentially delayed by the same angle θa from the top agitating blade, which has the most advanced phase, to the bottom agitating blade, which has the most delayed phase.

Due to the above phase relationship, as the multiple stirring blades 16a to 16f rotate around the shaft 15, a downward flow of molten glass is formed near the shaft 15 from above. In order to favorably form a flow of molten glass, it is preferable that the value of the above angle θa is 30° or more and 60° or less.

The impellers 16a to 16f extend perpendicularly to the shaft 15, i.e., along the radial direction of the shaft 15. Each of the impellers 16a to 16f has a pair of impellers 17 arranged symmetrically with respect to the shaft 15 (axially symmetric with respect to the central axis of the shaft 15). The impellers 17 are configured in a square rod shape, but may also be configured in a round rod shape or other irregular shapes. As shown in FIG. 4, the impeller 17 has a square cross section. This configuration is not limited, and the impeller 17 may have other polygonal or elliptical shapes, etc.

As shown in FIG. 4, the impellers 16a to 16f (impeller body 17) have a first corner 18a, a second corner 18b, a third corner 18c, and a fourth corner 18d. Furthermore, the impellers 16a to 16f have a first inclined surface 19a formed between the first corner 18a and the second corner 18b, a second inclined surface 19b formed between the first corner 18a and the third corner 18c, a third inclined surface 19c formed between the second corner 18b and the fourth corner 18d, and a fourth inclined surface 19d formed between the third corner 18c and the fourth corner 18d.

The first corner 18a is configured to face forward in the rotation direction T of the agitator blades 16a to 16f when the shaft 15 rotates in the rotation direction R. The second corner 18b is configured to face upward. The third corner 18c is configured to face downward. The fourth corner 18d is configured to face in the opposite direction to the first corner 18a. The fourth corner 18d is configured to face backward in the rotation direction T of the agitator blades 16a to 16f when the shaft 15 rotates in the rotation direction R. Not limited to this, the fourth corner 18d is configured to face forward in the rotation direction (opposite to the direction indicated by the symbol T) of the agitator blades 16a to 16f when the shaft 15 rotates in the opposite direction to the rotation direction R.

As shown in FIG. 4, the first inclined surface 19a and the second inclined surface 19b are configured to form an angle θ1 through the first corner portion 18a. This angle θ1 is preferably 45° or more and 150° or less. When the stirring blades 16a to 16f move in the rotation direction T, the first inclined surface 19a and the second inclined surface 19b move the molten glass in the directions indicated by the arrows A1 and A2 along the inclination direction. This allows the molten glass to be effectively stirred up and down. In addition, compared to when the stirring blades are configured in a plate shape as in the conventional case, the torque acting on the shaft 15 can be made as small as possible.

The first inclined surface 19a and the third inclined surface 19c are configured to form an angle θ2 with respect to the second corner portion 18b. The second inclined surface 19b and the fourth inclined surface 19d are configured to form an angle θ3 with respect to the third corner portion 18c. The third inclined surface 19c and the fourth inclined surface 19d are configured to form an angle θ4 with respect to the fourth corner portion 18d.

Each mixing blade 16a to 16f has a tip blade 20a to 20f at the tip of the blade body 17. Hereinafter, each tip blade 20a to 20f will be referred to as the first tip blade 20a to the sixth tip blade 20f, corresponding to the first mixing blade 16a to the sixth mixing blade 16f.

Each of the tip blades 20a-20f is fixed to each of the agitating blades 16a-16f so as to extend in the vertical direction. In other words, each of the tip blades 20a-20f is configured to be parallel to the shaft 15. Each of the tip blades 20a-20f has an upper end 21a and a lower end 21b. Each of the tip blades 20a-20f has the same shape and dimensions, but is not limited to this configuration. Each of the tip blades 20a-20f is configured in a rod shape (e.g., a round rod shape), but is not limited to this configuration.

The length L2 of the tip blades 20a-20f (see Figures 2 and 3) is preferably greater than the width W (see Figure 4) of the blade body 17 of each agitator blade 16a-16f (L2>W). The length L2 of the tip blades 20a-20f is preferably 1/3 to 1 of the spacing D between adjacent agitator blades in the vertical direction (D≧L2≧D/3). The spacing between each tip blade 20a-20f and the inner peripheral wall 12 of the agitator tank 6a is, for example, 3/20 or less of the inner diameter of the agitator tank 6a, and preferably 1/10 or less.

The first agitator blade 16a and the second agitator blade 16b are connected by a first connecting portion 22a. The second agitator blade 16b and the third agitator blade 16c are connected by a second connecting portion 22b. The fourth agitator blade 16d and the fifth agitator blade 16e are connected by a third connecting portion 22c. The fifth agitator blade 16e and the sixth agitator blade 16f are connected by a fourth connecting portion 22d. In a side view, each connecting portion 22a to 22d is inclined at a predetermined angle θb with respect to the axial direction of the shaft 15. Each connecting portion 22a to 22d has the same shape and the same dimensions, but is not limited to this configuration. Each connecting portion 22a to 22d is configured in a rod shape (round rod shape), but is not limited to this configuration.

The specific configurations and relationships of each mixing blade 16a-16f, tip blade 20a-20f, and each connecting portion 22a-22d are explained below.

2, the first agitator blade 16a and the second agitator blade 16b are arranged at a height that overlaps with the inlet 13 of the agitator tank 6a in the vertical direction. That is, the first agitator blade 16a and the second agitator blade 16b are located at a height between the upper end 13a and the lower end 13b of the inlet 13. The distance D between the first agitator blade 16a and the second agitator blade 16b is greater than the length L1 (length of the blade body 17) from the shaft 15 to the tip of each agitator blade 16a, 16b (D>L1). The first agitator blade 16a may be located above the upper end 13a of the inlet 13.

The upper end 21a of the first tip blade 20a is fixed to the tip of the first agitator blade 16a. This upper end 21a may protrude upward from the tip of the first agitator blade 16a. The lower end 21b of the first tip blade 20a protrudes downward from the tip of the first agitator blade 16a. The middle part of the second tip blade 20b is fixed to the tip of the second agitator blade 16b. The upper end 21a of the second tip blade 20b protrudes upward from the tip of the second agitator blade 16b. The lower end 21b of the second tip blade 20b protrudes downward from the tip of the second agitator blade 16b.

The first connecting portion 22a connects the lower end 21b of the first tip impeller 20a provided on the first agitator 16a to the upper end 21a of the second tip impeller 20b provided on the second agitator 16b. The first connecting portion 22a is provided within the height range between the upper end 13a and the lower end 13b of the inlet 13.

The third agitator blade 16c and the fourth agitator blade 16d are located within the height range between the inlet 13 and the outlet 14 of the agitator tank 6a. The third agitator blade 16c is positioned below the lower end 13b of the inlet 13.

The upper end 21a of the third tip impeller 20c protrudes upward from the tip of the third agitator 16c. The lower end 21b of the third tip impeller 20c is fixed to the tip of the third agitator 16c. This lower end 21b may protrude downward from the tip of the third agitator 16c.

A portion of the second connecting portion 22b is provided at a height above the lower end 13b of the inlet 13, but the entire portion may be provided at a height above the lower end 13b of the inlet 13.

The upper end 21a of the fourth tip blade 20d provided on the fourth agitating blade 16d is fixed to the tip of the fourth agitating blade 16d. This upper end 21a may protrude upward from the tip of the fourth agitating blade 16d. The lower end 21b of the fourth tip blade 20d protrudes downward from the tip of the fourth agitating blade 16d.

2 and 3, there is no connecting portion between the third agitating blade 16c and the fourth agitating blade 16d. Specifically, the lower end 21b of the third tip blade 20c provided on the third agitating blade 16c is not connected to a connecting portion. Therefore, the lower end 21b of the third tip blade 20c is a non-connecting portion that is not connected by a connecting portion. Similarly, the upper end 21a of the fourth tip blade 20d provided on the fourth agitating blade 16d is a non-connecting portion that is not connected by a connecting portion. In this way, by forming a non-connecting portion on the third agitating blade 16c and the fourth agitating blade 16d, a non-connecting area NCA in which no connecting portion exists between the tip of the third agitating blade 16c and the tip of the fourth agitating blade 16d can be formed. The non-connecting area NCA is formed within the height range between the inlet 13 and the outlet 14 of the agitating tank 6a, similar to the third agitating blade 16c and the fourth agitating blade 16d.

The fifth agitator blade 16e and the sixth agitator blade 16f are arranged at a height that overlaps with the outlet 14 in the vertical direction. That is, the fifth agitator blade 16e and the sixth agitator blade 16f are located at a height between the upper end 14a and the lower end 14b of the outlet 14. The sixth agitator blade 16f may be located below the lower end 14b of the outlet 14.

The fifth tip impeller 20e has its middle portion fixed to the tip of the fifth agitating impeller 16e. The upper end 21a of the fifth tip impeller 20e protrudes upward from the tip of the fifth agitating impeller 16e. The lower end 21b of the fifth tip impeller 20e protrudes downward from the tip of the fifth agitating impeller 16e.

The third connecting portion 22c connects the lower end portion 21b of the fourth tip blade 20d provided at the tip of the fourth agitating blade 16d to the upper end portion 21a of the fifth tip blade 20e provided at the tip of the fifth agitating blade 16e.

The sixth agitator blade 16f is located above the lower end 14b of the outlet 14. The upper end 21a of the sixth tip blade 20f protrudes upward from the tip of the sixth agitator blade 16f. The lower end 21b of the sixth tip blade 20f is fixed to the tip of the sixth agitator blade 16f. This lower end 21b may protrude downward from the tip of the sixth agitator blade 16f.

The fourth connecting portion 22d connects the lower end portion 21b of the fifth tip blade 20e provided at the tip of the fifth agitating blade 16e to the upper end portion 21a of the sixth tip blade 20f provided at the tip of the sixth agitating blade 16f.

The following describes a method for manufacturing a glass plate (glass article) using the manufacturing device 1 having the above configuration.

In this method, glass raw materials are melted in a melting furnace 2 (melting process) to obtain molten glass, and then this molten glass is subjected to a fining process in a fining chamber 3, a stirring process (homogenization process) by a stirring device 6, and a condition adjustment process between the stirring device 6 and a forming device 4. The molten glass is then transferred to the forming device 4, and a glass ribbon is formed from the molten glass (forming process). After the forming process, a glass plate of a specified size is formed through an annealing process in an annealing furnace and a cutting process of the glass ribbon by a cutting device.

The following describes in detail the implementation of the mixing process.

In the stirring process, the molten glass that has been through the fining process flows into the stirring tank 6a through the flow pipe 8 and the inlet 13. The molten glass that has flowed into the stirring tank 6a is stirred by the stirrer 11 as it descends within the stirring tank 6a. The stirrer 11 rotates the stirring blades 16a to 16f around the shaft 15 by rotating the shaft 15. This generates a swirling flow of molten glass within the stirring tank 6a. The specific aspects of the flow of molten glass within the stirring tank 6a are described below.

The first stirring blade 16a and the second stirring blade 16b of the stirrer 11 stir the molten glass by rotating. In addition, the first connecting part 22a connecting the first stirring blade 16a and the second stirring blade 16b moves near the inner wall 12 of the stirring tank 6a, thereby pushing the molten glass flowing near the inner wall 12 downward. As a result, as shown in FIG. 2, the speed of the downward flow F1 of the molten glass increases near the inner wall 12 of the stirring tank 6a. As a result, the speed of the downward flow F2 of the molten glass located inside (towards the shaft 15) of the first connecting part 22a becomes relatively slow.

The first tip blade 20a of the first agitating blade 16a and the second tip blade 20b of the second agitating blade 16b rotate together with the first connecting portion 22a near the inner wall 12 of the agitating tank 6a. As a result, the molten glass flowing between each tip blade 20a, 20b and the inner wall 12 of the agitating tank 6a is pressed between the inner wall 12 of the agitating tank 6a and the tip blades 20a, 20b. As a result, as shown in FIG. 2, a flow F3 is generated that replaces the molten glass on the outer side (inner wall 12 side) of each tip blade 20a, 20b with the molten glass on the inner side (shaft 15 side) of each tip blade 20a, 20b.

The molten glass that moves below the second stirring blade 16b is stirred by the second connecting portion 22b and the third stirring blade 16c. The second connecting portion 22b, like the first connecting portion 22a, increases the speed of the downward flow F1 of the molten glass near the inner wall 12 of the stirring tank 6a.

The third tip blade 20c provided at the tip of the third stirring blade 16c, like the first tip blade 20a and the second tip blade 20b, generates a flow F3 that exchanges the molten glass outside the third tip blade 20c (towards the inner circumferential wall 12) with the molten glass inside the third tip blade 20c (towards the shaft 15).

In the region between the third stirring blade 16c and the fourth stirring blade 16d, a non-connecting area NCA is formed, and a flow different from the flow of molten glass generated by stirring with the first stirring blade 16a and the second stirring blade 16b is generated. That is, in the region between the third stirring blade 16c and the fourth stirring blade 16d, since there is no connection, the speed of the flow F5 of molten glass around the shaft 15 is smaller than the speed of the flow F4 of molten glass above the third stirring blade 16c. By creating such a difference in the speed of the flow of molten glass, it is possible to promote the stirring of the molten glass between the third stirring blade 16c and the fourth stirring blade 16d.

The fourth tip impeller 20d provided on the fourth stirring impeller 16d, like the third tip impeller 20c, generates a flow F3 that exchanges the molten glass outside the fourth tip impeller 20d (towards the inner circumferential wall 12) with the molten glass inside the fourth tip impeller 20d (towards the shaft 15).

The molten glass that moves below the fourth stirring blade 16d is stirred by the third connecting portion 22c and the fifth stirring blade 16e. The third connecting portion 22c, like the second connecting portion 22b, increases the speed of the downward flow F1 of the molten glass near the inner wall 12 of the stirring tank 6a.

A portion of the molten glass stirred by the fifth stirring blade 16e and the fifth tip blade 20e is discharged from the outlet 14. Like the fourth tip blade 20d, the fifth tip blade 20e generates a flow F3 that exchanges the molten glass on the outer side of the fifth tip blade 20e (the inner peripheral wall 12 side) with the molten glass on the inner side of the fifth tip blade 20e (the shaft 15 side).

The molten glass that moves below the fifth stirring blade 16e is stirred by the fourth connecting portion 22d and the sixth stirring blade 16f. The fourth connecting portion 22d, like the third connecting portion 22c, increases the speed of the downward flow F1 of the molten glass near the inner wall 12 of the stirring tank 6a.

The molten glass stirred by the sixth stirring blade 16f and the sixth tip blade 20f is discharged from the outlet 14. The sixth tip blade 20f, like the fifth tip blade 20e, generates a flow F3 that exchanges the molten glass on the outer side of the sixth tip blade 20f (the inner peripheral wall 12 side) with the molten glass on the inner side of the sixth tip blade 20f (the shaft 15 side).

The molten glass discharged from the outlet 14 is transported to the pot 7 through the flow pipe 9.

According to the stirring device 6 according to the present embodiment described above, the stirring blades 16a to 16f are configured in a rod shape, and two adjacent stirring blades 16a to 16f in the vertical direction are connected by connecting portions 22a to 22d, thereby making it possible to improve the stirring capacity of the stirring device 6.

According to the inventor's research, it has been confirmed that the stirring device 6 according to this embodiment exhibits excellent stirring performance for molten glass flowing into the stirring tank 6a from the upper region of the inlet 13 (indicated by arrow FU), molten glass flowing into the stirring tank 6a from the central region of the inlet 13 (indicated by arrow FM), and molten glass flowing into the stirring tank 6a from the lower region of the inlet 13 (indicated by arrow FB) within the vertical range of the inlet 13, as shown in FIG. 2.

From the viewpoint of effectively stirring the molten glass (indicated by the arrow FM) flowing into the stirring tank 6a from the central region of the inlet 13, it is preferable to position the second stirring blade 16b in the central region of the inlet 13. For example, when the height dimension of the inlet 13 is H1 mm, it is preferable that the height of the center of the second stirring blade 16b is located within a range of ±0.2H1 with respect to the center of the inlet 13.

From the viewpoint of effectively stirring the molten glass (indicated by the arrow FU) flowing into the stirring tank 6a from the upper region of the inlet 13, the first stirring blade 16a is preferably positioned higher than the upper region of the inlet 13 or the upper end 13a of the inlet, and more preferably positioned higher than the upper end 13a of the inlet. For example, it is preferable that the height position of the center of the first stirring blade 16a is located within a range of ±0.2H1 based on the upper end 13a of the inlet, and more preferably within a range of +0.2H1 to 0.

From the viewpoint of effectively stirring the molten glass (indicated by the arrow FB) flowing into the stirring tank 6a from the lower region of the inlet 13, the third stirring blade 16c is preferably positioned lower than the lower region of the inlet 13 or the lower end 13b of the inlet, and more preferably positioned lower than the lower end 13b of the inlet. For example, it is preferable that the height position of the center of the third stirring blade 16c is located within a range of ±0.2H1 based on the lower end 13b of the inlet 13, and more preferably within a range of -0.2H1 to 0.

In order to assist the stirring by the above-mentioned first stirring blade 16a, second stirring blade 16b, and third stirring blade 16c, it is preferable to provide a first connecting portion 22a connecting the first stirring blade 16a and the second stirring blade 16b, and a second connecting portion 22b connecting the second stirring blade 16b and the third stirring blade 16c.

From the viewpoint of effectively stirring the molten glass flowing out from the central region of the outlet 14, it is preferable to position the fifth stirring blade 16e in the central region of the outlet 14. For example, when the height dimension of the outlet 14 is H2 mm, it is preferable that the height of the center of the fifth stirring blade 16e is located within a range of ±0.2H2 based on the center of the outlet 14.

From the viewpoint of effectively stirring the molten glass flowing out from the upper region of the outlet 14, the fourth stirring blade 16d is preferably positioned higher than the upper region of the outlet 14 or the upper end 14a of the outlet, and more preferably positioned higher than the upper end 14a of the outlet. For example, it is preferable that the height position of the center of the fourth stirring blade 16d is located within a range of ±0.2H2 based on the upper end 14a of the outlet, and more preferably within a range of +0.2H1 to 0.

From the viewpoint of effectively stirring the molten glass flowing out from the lower region of the outlet 14 into the stirring tank 6a, the sixth stirring blade 16f is preferably positioned lower than the lower region of the outlet 14 or the lower end 14b of the outlet, and more preferably positioned lower than the lower end 14b of the outlet. For example, it is preferable that the height position of the center of the sixth stirring blade 16f is located within a range of ±0.2H2 based on the lower end 14b of the outlet, and more preferably within a range of -0.2H1 to 0.

In order to assist the stirring by the fourth stirring blade 16d, the fifth stirring blade 16e, and the sixth stirring blade 16f described above, it is preferable to provide a third connecting portion 22c connecting the fourth stirring blade 16d and the fifth stirring blade 16e, and a fourth connecting portion 22d connecting the fifth stirring blade 16e and the sixth stirring blade 16f.

The present invention is not limited to the configuration of the above embodiment, nor is it limited to the above-mentioned effects. Various modifications of the present invention are possible without departing from the gist of the present invention.

In the above embodiment, an example was described in which a non-connecting area NCA is formed between the third and fourth agitating blades 16c and 16d among the multiple agitating blades 16a to 16f provided on the stirrer 11, but the present invention is not limited to this configuration. The present invention may also be configured such that a connecting portion is provided between the third and fourth agitating blades 16c and 16d.

In the above embodiment, the connecting portions 22a to 22d connect the tips of the blade bodies 17 associated with the agitating blades 16a to 16f, but the present invention is not limited to this configuration. The connecting portions 22a to 22d may connect the middle portions of the blade bodies 17 without connecting to the tip blades 20a to 20f. Alternatively, the present invention may employ a configuration in which some or all of the connecting portions 22a to 22d are omitted.

In the above embodiment, the shaft 15 of the stirrer 11 may be rotated in the opposite direction to the rotation direction R. In this case, when the multiple stirring blades 16a to 16f rotate around the shaft 15, the stirring blades on the upper end side of the shaft 15 will lag in phase around the shaft 15 relative to the stirring blades on the lower end side.

In other words, between two adjacent agitating blades, the relatively upper agitating blade lags in phase around the axis 15 by the phase angle θa with respect to the relatively lower agitating blade.

In this case, each stirring blade 16a-16f advances the fourth corner 18d forward in the swirling direction, and stirs the molten glass with the third inclined surface 19c and the fourth inclined surface 19d. In addition, each connecting portion 22a-22d operates to push up the molten glass in the stirring tank 6a when swirling, thereby generating an upward flow of molten glass in the vicinity of the inner wall 12 of the stirring tank 6a. As in the above embodiment, each tip blade 20a-20f generates a flow that replaces the molten glass on the outer side (inner wall 12 side) of each tip blade 20a-20f with the molten glass on the inner side (shaft 15 side) of each tip blade 20a-20f.

The inventors conducted a test to confirm the effects of the present invention. In this test, they prepared Example 1, which relates to the stirring device of the above embodiment, and Comparative Examples 1 and 2, which have a different configuration from Example 1, and compared the stirring performance of each example.

Figure 5 shows a stirrer used in the stirring tank of Comparative Example 1. The stirrer 11 of Comparative Example 1 has multiple stirring blades 16 arranged at equal intervals along the longitudinal direction of the shaft 15. Each stirring blade 16 is composed of a rectangular plate member. Each stirring blade 16 has multiple openings 16A. The multiple stirring blades 16 are fixed to the shaft 15 so that they each have a phase difference.

Figure 6 shows a stirrer used in a stirring tank according to Comparative Example 2. The stirrer 11 according to Comparative Example 2 has a number of stirring blades 16 arranged at equal intervals along the longitudinal direction of the shaft 15. Each stirring blade 16 is composed of a rectangular plate member. Each stirring blade 16 has a number of openings 16A. The multiple stirring blades 16 are fixed to the shaft 15 so that they each have a phase difference. Each stirring blade 16 is connected by a rod-shaped connecting portion 23.

The mixing vessel in each example was made of a transparent material, and the inside of the vessel could be seen from the outside. In the test, a transparent liquid was poured into the mixing vessel, and a colored liquid was mixed into the transparent liquid. In addition, by rotating the stirrer, it was visually confirmed whether the colored liquid was stirred to the point where it could no longer be seen. The mixing performance of each example was confirmed when the colored liquid was mixed into the transparent liquid in the upper region of the inlet (indicated by the arrow FU in Figure 2), when it was mixed into the transparent liquid in the central region of the inlet (indicated by the arrow FM in Figure 2), and when it was mixed into the transparent liquid in the lower region of the inlet (indicated by the arrow FB in Figure 2).

In this test, the following evaluation criteria were used for the stirring performance of each example. When the colored liquid disappeared (became unrecognizable) when the stirrer rotation speed was 5 rpm or less, it was rated as "◎" (best), and when the colored liquid disappeared when the stirrer rotation speed was more than 5 rpm and less than 10 rpm, it was rated as "○" (good). When the colored liquid disappeared when the stirrer rotation speed was more than 10 rpm and less than 15 rpm, it was rated as "△" (passable), and when the colored liquid did not disappear even when the stirrer rotation speed exceeded 15 rpm, it was rated as "×" (unacceptable).

The evaluation results are shown in Table 1.

As shown in Table 1, in Example 1, when the colored liquid was introduced into the stirring tank at different positions in the inlet, the colored liquid could be eliminated at all positions. In contrast, in Comparative Example 1 and Comparative Example 2, the colored liquid that had flowed into the stirring tank from the lower region of the inlet could not be eliminated.

In addition to the above evaluation, the torque acting on the shaft was measured using a torque meter attached to the shaft while the shaft rotation speed was kept constant (10 rpm), and the measured values were compared for Example 1, Comparative Example 1, and Comparative Example 2. As a result, it was found that the torque acting on the shaft in Comparative Example 1 was about the same as that in Example 1, and that the torque acting on the shaft in Comparative Example 2 was 1.2 times that of Example 1.

Based on the above, it was confirmed that the mixing tank of Example 1 according to the present invention exhibits higher mixing performance than the mixing tanks of Comparative Examples 1 and 2.

Description of the Preferred Embodiments 6 Stirring device 6a Stirring tank 11 Stirrer 13 Inlet 14 Outlet 15 Shaft 16a First stirring blade 16b Second stirring blade 16c Third stirring blade 16d Fourth stirring blade 16e Fifth stirring blade 16f Sixth stirring blade 18a First corner portion 20a First tip blade 20b Second tip blade 20c Third tip blade 20d Fourth tip blade 20e Fifth tip blade 20f Sixth tip blade 21a Upper end portion 21b of tip blade Lower end portion 22a of tip blade First connecting portion 22b Second connecting portion 22c Third connecting portion 22d Fourth connecting portion NCA Non-connecting region

Claims (8)

A molten glass stirring device comprising: a stirrer having a shaft extending in a vertical direction and a plurality of stirring blades arranged along the longitudinal direction of the shaft; a stirring tank containing the stirrer; and a rotating device for rotating the stirrer,
The stirring blade is rod-shaped,
The adjacent stirring blades in the longitudinal direction of the shaft have a phase difference,
The stirrer is a mixing device characterized in that it has a connecting portion that connects two adjacent mixing blades among the plurality of mixing blades. The stirring device according to claim 1, wherein the stirring blade has a tip blade provided at the tip of the stirring blade. The tip wing is rod-shaped extending in the vertical direction and has an upper end and a lower end,
The stirring device according to claim 2 , wherein the connecting portion is connected to the upper end portion or the lower end portion of the tip blade. The stirring blade has a corner in cross section,
The stirring device according to claim 1 , wherein the corner portion is configured to face forward in the rotation direction of the stirring blade. The stirrer is a stirring device according to any one of claims 1 to 3, in which the stirrer has a non-connected area in which the connecting portion is not formed between two adjacent stirring blades among the plurality of stirring blades. the stirring tank includes an inflow inlet through which the molten glass flows, and an outflow outlet provided below the inflow inlet and through which the molten glass flows out,
The connecting portion is located at the height of the inlet and the outlet,
The mixing device according to claim 5 , wherein the non-connected region is located between the inlet and the outlet. A stirrer having a shaft extending in the vertical direction and a plurality of stirring blades arranged along the longitudinal direction of the shaft,
The stirring blade is rod-shaped,
The two adjacent stirring blades in the longitudinal direction of the shaft have a phase difference,
The stirrer is characterized in that it has a connecting portion that connects two adjacent stirring blades among the plurality of stirring blades. A method for producing a glass article, comprising: a stirring step of stirring the molten glass in the stirring tank by using the stirring device according to any one of claims 1 to 3.

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