TWI401222B - Flame glass degassing device - Google Patents

Description

Defoaming device for molten glass Technical field

The present invention relates to a defoaming device for molten glass for removing bubbles from continuously supplied molten glass.

Background technique

Conventionally, in order to improve the quality of a molded glass product, a clarification process capable of removing bubbles generated in the molten glass is used before molding the molten glass obtained by melting the raw material in a melting furnace by a molding apparatus. .

In the clarification process, sodium sulfate (Na ₂ SO ₄ ) or the like is added as a clarifying agent in advance to the raw material, and then the molten glass obtained by the molten raw material is retained at a predetermined temperature for a certain period of time, thereby allowing the molten glass to be contained therein. The method of removing and floating bubbles to remove them is known.

Further, the molten glass is introduced into a reduced pressure atmosphere, and the bubbles in the continuously flowing molten glass flow are grown in the reduced pressure environment, and the bubbles contained in the molten glass are removed and defoamed, and then removed. A vacuum degassing method for discharging in a pressurized environment is also known.

Such a vacuum degassing method moves the molten glass flow in a reduced pressure degassing tank in a reduced pressure environment, specifically, a predetermined reduced pressure inside, after the molten glass flow is formed. When moving in the vacuum degassing tank, the bubbles contained in the molten glass are allowed to grow in a short period of time, and then floated in the molten glass by the buoyancy of the grown bubbles to defoam the bubbles on the surface of the molten glass. Thereby, the removal of bubbles can be efficiently performed from the surface of the molten glass. At this time, in order to effectively remove the bubbles from the surface of the molten glass and move in the vacuum degassing tank, it is necessary to increase the floating speed of the bubbles so that the bubbles in the molten glass float up to the surface of the molten glass. Otherwise, the molten glass containing bubbles will flow out from the decompression defoaming tank, so that the final product becomes a bubble.

Therefore, it is conceivable to reduce the pressure of the decompression environment in which decompression and defoaming is performed as much as possible, and to increase the buoyancy speed by increasing the bubble size, thereby improving the effect of decompression under reduced pressure. However, if the pressure of the reduced-pressure environment in which decompression and defoaming is performed is reduced, there are cases where a large number of new bubbles are generated inside the molten glass, and the bubbles do not float up to the surface of the molten glass to defoam, but a large amount of floating The bubble layer is formed, and a part of the bubble layer is discharged together with the molten glass to become a bubble-containing molten glass. Further, when the bubble layer grows, the liquid surface temperature of the molten glass flow is lowered, and it becomes difficult to defoam, and the bubble layer is further developed. As a result, the tank in the reduced pressure environment is filled with bubbles that are not defoamed. Therefore, it is feared that the bubble layer filled in the groove contacts the impurities adhering to the ceiling portion of the groove, and finally the impurities are mixed into the molten glass. Therefore, from the viewpoint of effectively performing the vacuum degassing treatment, it is not preferable to excessively reduce the pressure in the reduced pressure environment (see Patent Document 1).

Further, the floating speed of the bubbles in the molten glass depends on the viscosity of the molten glass in addition to the size of the bubbles, so that it is possible to reduce the viscosity of the molten glass, that is, to increase the temperature of the molten glass, thereby making the bubbles effective. Going up. However, if the temperature of the molten glass is higher than necessary, the reaction between the molten glass and the contact flow path material, for example, a refractory such as brick, is activated, and in addition to generating new bubbles in the molten glass, the flow path material may be A part of the solution is dissolved in the molten glass to cause a decrease in the quality of the glass. Further, when the temperature of the molten glass is increased, in addition to the decrease in the strength of the flow path material itself and the shortening of the life of the device, unnecessary equipment such as a heating device for maintaining the temperature of the molten glass is required. Therefore, in order to appropriately and efficiently perform the vacuum degassing treatment of the molten glass, the pressure is not excessively lowered, and the set temperature of the molten glass is not required to be high (see Patent Document 1).

Advanced technical literature Patent literature

Patent Document 1: JP-A-2000-302456

Invention

In order to solve the problems of the prior art, it is an object of the present invention to provide a defoaming device for molten glass which can improve the clarifying effect without changing the conditions of the clarification procedure such as the degree of pressure reduction or the temperature of the molten glass.

In order to achieve the above object, the present invention provides a defoaming device for molten glass, which comprises a defoaming tank having an inlet and a discharge port of molten glass, wherein the defoaming tank is provided with a first member and In the bubble floating mechanism of the second member, the first member is attached to the inner wall of the defoaming tank, and at least a part thereof is immersed in the molten glass, and is disposed so as to flow through the molten glass flow of the defoaming tank. In the entire width direction of the road, the second member is attached to the inner wall of the defoaming tank, and extends upward from the bottom surface side of the defoaming tank, and the first member and the second member are disposed to satisfy the following (1)~(3).

(1) The first member is located on the upstream side in the flow direction of the molten glass with respect to the second member.

(2) The distance between the first member and the second member in the flow direction of the molten glass is 50 to 400 mm.

(3) when the height of the bottom surface of the defoaming tank to the lower end of the first member is h ₁ and the height of the bottom surface of the defoaming tank to the upper end of the second member is h ₂ , the relationship h _{1 is} satisfied. ≦h ₂ .

In the defoaming device for molten glass of the present invention, the second member is preferably provided with a gap through which the molten glass can pass.

Further, in the defoaming device for molten glass of the present invention, it is preferable that a gap between the inner wall of the defoaming tank and the second member is allowed to pass through the molten glass.

Further, in the defoaming device for molten glass of the present invention, when the maximum value of the inner diameter of the defoaming tank in the horizontal direction is W ₁ and the maximum value of the lateral width of the second member is W ₂ , it is preferable to satisfy The relationship is 0.2 ≦ W ₂ /W ₁ ≦ 0.9.

Further, in the defoaming device for molten glass of the present invention, the height h ₁ of the bottom surface of the defoaming tank to the lower end of the first member is preferably 70 to 250 mm.

Further, in the defoaming device for molten glass of the present invention, the planar shape of the first member preferably satisfies the following formula.

W ₁ <W ₂

(wherein W ₁ is a transverse width of the first member in the upstream side in the flow direction of the molten glass, and W ₂ is a transverse width of the first member in the downstream side in the flow direction of the molten glass.)

Further, in the defoaming device for molten glass of the present invention, two or more of the bubble floating mechanisms may be provided in the defoaming tank.

According to the defoaming device for molten glass of the present invention, the residual bubbles existing in the layer of the molten glass can be defoamed without changing the conditions of the clarification procedure such as the degree of decompression or the temperature of the molten glass, and the clarification effect of the molten glass can be improved. The defoaming device for molten glass of the present invention exhibits particularly excellent effects when used as a vacuum degassing apparatus. However, even as a clarification method other than the vacuum degassing method, for example, a high-temperature clarification method and He is used. When the clarifying agent is clarified, the sulphurization method using Sb or As oxide as a clarifying agent, or a combination of such a defoaming device, it is also possible to exhibit an effect superior to that of the conventional defoaming device.

Simple illustration

Fig. 1 is a cross-sectional view showing a structural example of one of the defoaming devices for molten glass of the present invention.

Fig. 2 is a perspective view showing a cross section of a portion of the defoaming device 10 shown in Fig. 1 excised.

Fig. 3 is a plan view of the defoaming device 10 shown in Fig. 1.

Fig. 4 is a cross-sectional view showing a line A-A' of the defoaming tank (cross-sectional ellipse) 11 shown in Fig. 1.

Fig. 5 is a cross-sectional view showing a cross section taken along line B-B' of the defoaming tank (cross-sectional elliptical shape) 11 shown in Fig. 1.

Fig. 6 is a cross-sectional view showing a cross section taken along line A-A' of the defoaming tank (section rectangle) 11 shown in Fig. 1.

Fig. 7 is a cross-sectional view showing a cross section taken along the line B-B' of the defoaming tank (cross-sectional rectangle) 11 shown in Fig. 1.

Fig. 8 is a cross-sectional view showing a cross section taken along the line A-A' of the defoaming tank (cross-section trapezoid) 11 shown in Fig. 1.

Fig. 9 is a cross-sectional view showing a cross section taken along the line B-B' of the defoaming tank (cross-section trapezoid) 11 shown in Fig. 1.

Fig. 10 is a plan view showing the planar shape of the first member into a substantially V-shaped defoaming device 10.

Fig. 11 is a plan view of the defoaming device 10 in which the planar shape of the first member is formed into a stepped shape (convex shape).

Fig. 12 is a cross-sectional view showing a cross section taken along the line B-B' of the defoaming groove (cross-sectional elliptical shape) 11 of the second member formed in a T shape.

Fig. 13 is a cross-sectional view showing a cross section taken along the line B-B' of the defoaming groove (cross-sectional elliptical shape) 11 of the second member formed in a strip shape.

Fig. 14 is a cross-sectional view showing a cross section taken along the line B-B' of the defoaming groove (cross-sectional rectangle) 11 of the second member formed in a T shape.

Fig. 15 is a cross-sectional view showing a cross section taken along the line B-B' of the defoaming groove (cross-sectional rectangle) 11 of the second member formed in a strip shape.

Fig. 16 is a plan view showing the defoaming device 10 of the molten glass of the present invention, in which the third member 17 is disposed on the downstream side of the second member 15.

Fig. 17 is a cross-sectional view taken along the line C-C' of the section elliptical defoaming groove 11.

Fig. 18 is a cross-sectional view showing a section taken along the line C-C' of the rectangular section defoaming groove 11.

Best form for implementing the invention

Hereinafter, the present invention will be described with reference to the drawings.

1 is a cross-sectional view showing a structural example in which a defoaming device for molten glass of the present invention (hereinafter referred to as "the defoaming device of the present invention") is configured as a vacuum degassing device. The defoaming device of the present invention is preferably configured as a vacuum degassing device, but even a defoaming device for molten glass other than the vacuum degassing device, for example, clarification using a high temperature clarification method and He as a clarifying agent The method, the use of an oxide of Sb or As as a clarifying agent, or a combination of such a defoaming device, can also exhibit an excellent clarifying effect. When the defoaming device of the present invention is configured as the defoaming device other than the vacuum degassing device, the first member and the second member which are the bubble floating mechanisms to be described later are provided in the defoaming tank of the defoaming device.

The defoaming device (pressure reducing defoaming device) 10 shown in Fig. 1 has a hollow defoaming tank (pressure reducing degassing tank) 11 constituting a flow path of the molten glass. The cross-sectional shape of the defoaming tank 11 may be a circular shape such as a circular shape, a semicircular shape, or an elliptical shape, and may be a polygonal shape such as a rectangular shape, a trapezoidal shape, a hexagonal shape, or an octagonal shape.

The degassing tank (pressure degassing tank) 11 has an internal gas pressure set to be lower than atmospheric pressure to float and defoam the bubbles in the supplied molten glass G. The defoaming tank (pressure reducing degassing tank) 11 has an introduction port and a discharge port of molten glass, and an inlet pipe of the molten glass is connected to the riser pipe 12, and a discharge pipe 13 is connected to the discharge port of the molten glass. The riser 12 is introduced into the molten glass G of the defoaming tank (pressure reducing degassing tank) 11 by sucking the molten glass G before the defoaming treatment and raising it. Therefore, the lower end portion of the riser pipe 12 is immersed in the molten glass G in the upstream tank 220. The molten glass G is supplied into the upstream tank 220 from the melting tank 200. On the other hand, the downcomer 14 is a deriving mechanism for the molten glass G which is obtained by descending the molten glass G after the defoaming treatment from the defoaming tank (pressure reducing degassing tank) 11. Therefore, the lower end portion of the downcomer 13 is immersed in the molten glass G in the downstream tank 240. The molten glass G in the downstream tank 240 is led to a processing tank (not shown) for the post-process.

Hereinafter, in the present specification, the terms "upstream" and "downstream" mean upstream and downstream of the flow direction of the molten glass G flowing through the defoaming device 10. When the "upstream side" and the "downstream side" are mentioned, it means the upstream side and the downstream side of the flow direction of the molten glass G which flows through the defoaming apparatus 10.

Further, although not shown, the defoaming tank (pressure reducing degassing tank) 11 is usually housed in a decompression housing, and the decompression housing is suction-reduced at a reduced pressure, thereby deactivating the degassing tank. The gas pressure inside the bubble tank 11 is maintained at a reduced pressure state lower than atmospheric pressure. On the other hand, when the defoaming tank (pressure reducing degassing tank) 11 is not housed in the decompression housing, the upper space of the molten glass G of the defoaming tank (pressure reducing degassing tank) 11 is used by a decompression pump or the like. The pressure reduction is performed, whereby the air pressure inside the vacuum degassing tank 11 is maintained at a reduced pressure state lower than atmospheric pressure.

In the defoaming device (pressure reducing defoaming device) 10 of the present invention, a bubble floating mechanism having the first member 14 and the second member 15 is provided in the defoaming tank (pressure reducing degassing tank) 11.

Hereinafter, the bubble floating mechanism will be described with reference to Figs. 2 to 9 in the first drawing.

Fig. 2 is a perspective view showing a cross section of a portion of the defoaming device (pressure degassing device) 10 shown in Fig. 1 excised. In addition, the perspective view of Fig. 2 is a view in which the cross-sectional shape of the defoaming tank (pressure reducing degassing tank) 11 is a rectangle. Fig. 3 is a plan view showing a defoaming device (pressure degassing device) 10 shown in Fig. 1. However, in order to see the internal structure of the defoaming tank (pressure reducing degassing tank) 11, the wall surface of the upper part of the defoaming tank (pressure reducing degassing tank) 11 is abbreviate|omitted. Figs. 4, 6, and 8 are cross-sectional views showing the defoaming tank (pressure reducing degassing tank) 11 cut along the line A-A'. The fifth, seventh, and ninth drawings are cross-sectional views of the defoaming tank (pressure reducing degassing tank) 11 taken along the line B-B'. Further, the cross-sectional shape of the defoaming tank (pressure reducing degassing tank) 11 (11a) shown in Figs. 4 and 5 is elliptical, and the defoaming tank (pressure degassing tank) shown in Figs. The cross-sectional shape of (11b) is a rectangle, and the cross-sectional shape of the defoaming tank (pressure reducing degassing tank) 11 (11c) shown in Figs. 8 and 9 is trapezoidal.

In the figure, the first member 14 is attached to the inner wall of the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c), and at least a part thereof is immersed in the molten glass G, and is arranged in a horizontal direction. The entire width direction of the flow path of the molten glass in the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c).

The second member 15 is attached to the inner wall of the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c) to be self-degassing tank (pressure reducing degassing tank) 11 (11a, 11b, 11c) The bottom surface extends upward.

In the figure, the first member 14 and the second member 15 are directly attached to the inner wall of the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c), but may be indirectly attached to the defoaming tank through the supporting member. The inner wall of the (pressure reducing degassing tank) 11 (11a, 11b, 11c).

In the defoaming device (pressure reducing defoaming device) 10 of the present invention, the first member 14 and the second member 15 are disposed in the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c) so as to satisfy the following Said equations (1) ~ (3).

(1) The first member 14 is located on the upstream side with respect to the second member 15.

(2) The distance d between the first member 14 and the second member 15 in the flow direction of the molten glass G is 50 to 400 mm.

(3) Let the height of the bottom surface of the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c) to the lower end of the first member 14 be h ₁ , and let the defoaming tank (pressure degassing tank) 11 When the height of the bottom surface of (11a, 11b, 11c) to the upper end of the second member 15 is h ₂ , the relationship h ₁ ≦ h _{2 is} satisfied.

The vacuum degassing method is to increase the bubbles in the molten glass flow by allowing the molten glass to be held inside the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c) in a reduced pressure state. Lifting to the surface of the molten glass to defoam, thereby removing bubbles in the molten glass, but according to various conditions at the time of degassing under reduced pressure, for example, a defoaming tank (pressure degassing tank) 11 (11a, 11b, The degree of pressure reduction in 11c), the temperature in the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c), and the supply to the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c) The amount of bubbles in the molten glass, the flow rate of the molten glass in the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c), etc., and some of the bubbles existing in the molten glass cannot float up to the melting. The condition of the glass surface. Such residual bubbles cannot be removed by defoaming under reduced pressure.

The inventors of the present invention conducted research on the movement of the bubbles in the molten glass, and as a result, found that such residual bubbles are mainly present in the layer of the molten glass. Here, the layer among the molten glass means that among the molten glass G flowing in the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c), except for the surface layer (the liquid level of the molten glass G is h) In the case, the portion other than the upper side of 0.95 h) and the bottom layer (the portion where the liquid level of the molten glass G is h, which is lower than the portion of 0.2 h). In other words, the layer in the molten glass refers to a portion of 0.2 to 0.95 h when the liquid level of the molten glass G is h.

In the defoaming device (pressure degassing device) of the present invention, by providing the first member 14 and the second member 15 satisfying the above-described contents as a bubble floating mechanism, a layer of molten glass containing residual bubbles can be induced to the molten glass. The surface layer.

When the middle layer of the molten glass containing the residual bubbles is induced to the surface layer of the molten glass, the residual bubbles become present near the surface of the molten glass, and the head pressure of the molten glass becomes small, so that the residual bubbles are left. It will become easy to grow and promote the defoaming of residual bubbles. As a result, the clarification effect of the molten glass is enhanced.

In the defoaming device (pressure degassing device) 10 of the present invention, it is necessary to provide the first member 14 and the second member 15 satisfying the above contents as the bubble floating mechanism.

The structure similar to the appearance of the first member is disclosed as the barrier members 36a, 36b, 336a, and 336b in the vacuum degassing apparatus for molten glass shown in JP-A-2000-7344. Further, in the glass melting furnace described in Japanese Laid-Open Patent Publication No. H9-124323, the structure is similar to the horizontal member 14 which divides the upstream zone and the downstream zone of the melting furnace.

However, these configurations are functionally different from the bubble floating mechanism of the present invention. In the vacuum degassing apparatus for molten glass shown in JP-A-2000-7344, the barrier members 36a, 36b, 336a, and 336b are air bubbles that float up to the surface of the molten glass until reaching the barrier members 36a, 36b, 336a, and 336b. Those who are both blocked and defoamed have no intention of inducing a layer of molten glass containing residual bubbles to the surface layer (surface) of the molten glass. On the other hand, in the glass melting furnace disclosed in Japanese Laid-Open Patent Publication No. H9-124323, the traverse 14 is divided into an upstream zone and a downstream zone of the melting furnace 14, and will be in the upstream zone and the downstream zone, respectively. The convection recirculation of the formed molten glass is separated, and there is no intention to induce a layer of molten glass containing residual bubbles to the surface layer (surface) of the molten glass. In the glass melting furnace disclosed in Japanese Laid-Open Patent Publication No. H9-124323, the downstream zone defined by the diaphragm 14 is a clarified region of the molten glass, but the condensed glass is convected in the downstream zone. Thereby, the clarifier of the molten glass is used, and the defoaming device of the present invention is clarified by passing the molten glass through a defoaming tank (pressure reducing degassing tank) maintained under a reduced pressure state (minus) The pressure defoaming device) is significantly different in terms of clarification for molten glass. Moreover, due to the presence of the cross-over 14, the molten glass of the downstream zone is not induced to the surface of the molten glass (above), but is induced to the lower side. As apparent from the above, the barrier members 36a, 36b, 336a, and 336b shown in Japanese Laid-Open Patent Publication No. 2000-7344 and the crosspiece 14 shown in Japanese Laid-Open Patent Publication No. H9-124323 have completely different functions and functions. It is also completely different from the bubble floating mechanism of the present invention. Further, JP-A-2000-7344 and JP-A-H9-124323 do not disclose the existence of residual bubbles in the layer of the molten glass, and of course, there is no mention that the residual bubbles must be removed by floating and defoaming. Therefore, the barrier members 36a, 36b, 336a, and 336b shown in Japanese Laid-Open Patent Publication No. 2000-7344 and the horizontal member 14 shown in Japanese Laid-Open Patent Publication No. H9-124323 are similar in appearance to the first member and the second member of the present invention. Similarly, the combination of the barrier members 36a, 36b, 336a, 336b and the crosspiece 14 as a bubble floating mechanism of the present invention is by no means an easily achievable invention for those of ordinary skill in the art.

In the defoaming device (pressure degassing device) of the present invention, by disposing the first member and the second member in an appropriate position in the defoaming tank (pressure reducing degassing tank), melting of residual bubbles can be generated. The middle layer of glass effectively rises in flow. Further, as will be described later, a gap through which the molten glass can pass is provided between the inner wall of the defoaming tank (pressure reducing degassing tank) and the second member, or a gap through which the molten glass can pass is provided in the second member itself. Thereby, the residual bubbles which have been floated are not lowered and are retained in the vicinity of the surface layer. The defoaming efficiency is increased by these effects.

In the defoaming device (pressure degassing apparatus) 10 of the present invention, in order to exhibit the effect of providing a bubble floating mechanism, that is, the effect of inducing a layer of molten glass containing residual bubbles to the surface layer (surface) of the molten glass It is necessary to arrange the first member 14 so as to traverse the entire width direction of the flow path of the molten glass G of the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c).

When the liquid level of the molten glass G is h, the height h ₁ of the bottom surface of the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c) to the lower end of the first member 14 is h ₁ = 0.2 h. ~0.8h is better. For example, when the liquid level h of the molten glass G is 300 mm, the h ₁ is preferably 60 to 240 mm.

h ₁ If the above range, the molten glass in the middle of the play-containing residual bubbles of molten glass to a surface layer induced by the effect of over-based aspects, and, by providing the first member 14, may make degassing vessel (reduced pressure The flow of the molten glass G in the defoaming tanks 11 (11a, 11b, 11c) is not hindered.

It is preferred that h ₁ = 0.25 h - 0.75 h, and more preferably 0.3 h - 0.7 h.

In addition, the relationship between the height D of the molten glass flow path of the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c) and the liquid level height h of the molten glass G is due to the defoaming tank (decompression decompression) The type of the groove 11 (11a, 11b, 11c) is different, and in the case of a defoaming tank made of platinum or a platinum alloy (depressurization degassing tank), it is usually D=1.1 to 4.0 h, and 1.25~2.7h is preferred, and 1.3~2.4h is preferred. On the other hand, in the case of a defoaming tank (pressure degassing tank) made of a dense refractory material, it is usually D=1.8 to 7.0 h, and preferably 2.0 to 5.4 h, and 2.3 to 4.7 h. Preferably.

In the defoaming device (pressure degassing device) 10 of the present invention, the shape of the first member is not limited to the one shown in the drawings.

For example, in the cross-sectional shape shown in Fig. 1, the first member 14 is vertically disposed with respect to the horizontal direction, but the first member 14 may be inclined toward the downstream side or the upstream side. For example, when the inclination angle when the upper end of the first member 14 is inclined toward the downstream side is positive (when the inclination angle when the upper end of the first member 14 is inclined toward the upstream side is negative), the inclination angle α is -30°. In the range of +30°, the first member 14 may be inclined toward the downstream side or the upstream side.

Further, in the planar shape shown in FIG. 3, the first member 14 has a flat shape, but the planar shape of the first member 14 is not limited thereto. Figures 10 and 11 are the same plan views as in Figure 3. However, the planar shape of the first member is different from that of the first member 14 shown in FIG. The planar shape of the first member 14a shown in Fig. 10 is slightly V-shaped, and the planar shape of the first member 14b shown in Fig. 11 is convex (stepped). Further, in the figures 10 and 11, the planar shape of the second member is also different from that of Fig. 3. The second member shown in Fig. 10 is the second member 15a shown in Figs. 12 and 14, and the second member shown in Fig. 11 is the second member 15b shown in Figs.

The first members 14a and 14b shown in Figs. 10 and 11 have an effect of inducing a layer of molten glass containing residual bubbles to the surface layer of the molten glass, which is superior to the flat first member 14 shown in Fig. 3 .

However, when the first member having a substantially V-shaped planar shape is used, the first member 14a shown in Fig. 10 must have a narrow V-shape on the upstream side. Similarly, when the first member having a convex planar shape is used, the first member 14b shown in Fig. 11 must have a narrow lateral width on the upstream side.

When the first member having a different lateral shape on the upstream side and the downstream side is used, it is necessary to satisfy the following formula (1).

w ₁ <w ₂ .........(1)

In the formula, w ₁ is the lateral width of the first member on the upstream side, and w ₂ is the lateral width of the first member on the downstream side.

The first member having the planar shape satisfying the above formula (1) is melted without residual bubbles even if it is not the first member 14a of the slightly V shape shown in Fig. 10 or the first member 14b of the convex shape shown in Fig. 11. The effect of inducing the middle layer of the glass to the surface layer of the molten glass is also superior to that of the flat first member 14 shown in Fig. 3. The first member having the planar shape satisfying the above formula (1) may be a first member having a U-shaped planar shape, in addition to the above.

When the first member having a different lateral shape on the upstream side and the downstream side is used, it is preferable to satisfy the following formula (2), and it is more preferable to satisfy the following formula (3).

w ₁ <0.5×w ₂ .........(2)

w ₁ <0.1×w ₂ .........(3)

Further, in the cross-sectional shapes shown in Figs. 4, 6, and 8, the first member 14 is immersed in a horizontal flat plate on the lower surface of the molten glass, but the shape of the first member is not limited thereto. For example, in the cross-sectional shape in the direction shown in the fourth, sixth, and eighth directions, the first member may be immersed in the lower surface of the molten glass to have a deformed portion such as a convex portion or a concave portion. Further, the first member may be immersed in the lower surface of the molten glass in a shape bent into a U shape or the like.

As shown in the second, third, fifth, seventh, and ninth diagrams, the second member 15 is different from the first member 14 and is not disposed to cross the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c). Between the second member 15 and the inner wall (side wall) of the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c), the molten glass G is present in the entire width direction of the flow path of the molten glass. The gap passed.

When the second member 15 is disposed so as to traverse the entire width direction of the flow path of the molten glass of the defoaming tank (pressure reduction degassing tank) 11 in the same manner as the first member 14, the molten glass containing the residual bubbles can be exhibited. The middle layer is induced to the surface layer (surface) of the molten glass, but as shown in the second, third, fifth, seventh, and ninth views, the second member 15 and the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, When a gap through which the molten glass G can pass is provided between the inner walls (side walls) of 11c), it is preferable to prevent the molten glass induced to the surface layer of the molten glass from moving downward.

The defoaming device (pressure degassing device) 10 of the present invention induces a layer of molten glass containing residual bubbles to the surface of the molten glass by a bubble floating mechanism, but the molten glass originally located in the middle layer moves to the surface layer, fearing There is a tendency that the molten glass induced to the surface layer of the molten glass moves downward, and the residual bubbles are not defoamed.

As shown in the figures 2, 3, 5, 7, and 9, the second member 15 and the inner wall (side wall) of the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c) are provided. The gap through which the molten glass G passes is induced to the lower side of the molten glass of the surface layer of the molten glass by the bubble floating mechanism, and flows into the molten glass having no residual bubbles passing through the gap, or the molten glass containing a small amount of residual bubbles. In addition, since it becomes a middle layer of a new molten glass, the molten glass which is induced to the surface layer of the molten glass does not move downward, and the residual bubble can be defoamed, and the clarification effect of the molten glass is improved. Here, the molten glass containing a small amount of residual bubbles means that when the number of residual bubbles in the layer of the molten glass is a/kg, the number of residual bubbles is 0.01 × a/kg or less, and 0.005 × a/ It is preferably kg or less, and preferably 0.001 x a/kg or less of molten glass.

Fig. 12 and Fig. 13 are the same views as Fig. 5, and Fig. 14 and Fig. 15 are the same as Fig. 7. However, the shape of the second member is different from that of Figs. 5 and 7. The second member 15a shown in Figs. 12 and 14 has a substantially T-shaped cross-sectional shape, and is a T-shaped second member 15b and an inner wall of the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b) ( Between the side walls and the wall surface of the bottom, there is a gap 16 through which the molten glass G can pass.

The second member 15b shown in Figs. 13 and 15 has a strip shape, and is a strip-shaped second member 15b and an inner wall of the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b) (bottom portion) Between the walls, there is a gap 16 through which the molten glass G can pass.

Even in the structure of Fig. 12 to Fig. 15, the molten glass which has been introduced into the surface layer of the molten glass by the bubble floating mechanism flows into the molten glass which has passed through the gap, and becomes a new layer of molten glass, so that it is induced. The molten glass to the surface layer of the molten glass does not move downward, and the residual bubbles can be defoamed, thereby improving the clarifying effect of the molten glass.

Further, in the illustrated embodiment, a gap between the second member and the inner wall of the defoaming tank (depressurization degassing tank) (the wall surface of the side wall and the bottom) is allowed to pass through the molten glass, but the second member itself There may also be gaps through which the molten glass can pass.

In the second member, the second member 15 shown in the fifth, seventh, and ninth views has a simple shape, which is advantageous for production, and is easily attached to the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b). The inner wall of 11c) is particularly preferable because the above-described effect by providing a gap is excellent. In other words, in the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c), the flow rate of the molten glass in the central portion of the molten glass flow path is increased, and the residence time of the molten glass is shortened, so that it is in the molten glass. In the middle layer, the number of bubbles passing through the center portion of the molten glass flow path per hour becomes larger than that of the side portions of the molten glass flow path. The shape of the second member 15 shown in the fifth, seventh, and ninth views is excellent in that the residual air bubbles in the molten glass passing through the center portion of the molten glass flow path are excellent in defoaming.

The second member 15 shown in Figs. 5, 7, and 9 is excellent in the effect of inducing the layer of the molten glass containing the residual bubbles to the surface layer of the molten glass and the above-described effects by providing the gap. When the maximum value of the inner diameter in the horizontal direction of the defoaming tank (pressure reducing degassing tank) 11 is W ₁ and the maximum value of the lateral width of the second member 15 is W ₂ , the relationship is satisfied. W ₂ /W ₁ ≦0.9 is preferred.

The second member 15 shown in Figs. 5, 7, and 9 is preferably in a relationship of 0.3 ≦ W ₂ /W ₁ ≦ 0.85, and more preferably satisfies the relationship of 0.5 ≦ W ₂ /W ₁ ≦ 0.8.

In the defoaming device (pressure degassing device) 10 of the present invention, the height of the bottom surface of the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b, 11c) to the lower end of the first member 14 is h ₁ , When the height from the bottom surface of the defoaming tank (pressure reducing degassing tank) 11 to the upper end of the second member 15 is h ₂ , the relationship h ₁ ≦h _{2 is} satisfied, whereby the molten glass containing the residual bubbles can be exhibited. The effect of the middle layer on the surface layer of the molten glass.

In the defoaming device (pressure reducing defoaming device) 10 of the present invention, it is preferable that h ₁ and h ₂ satisfy the following formula (4).

h ₂ -h ₁ ≧20mm (4)

When the liquid level of the molten glass G is h, it is preferable to use h ₂ ≧ 0.3 h. For example, when the liquid level h of the molten glass G is 300 mm, it is preferable that h ₁ is 90 mm or more.

When h ₂ is in the above range, the effect of inducing a layer of molten glass containing residual bubbles to the surface layer of molten glass is exhibited.

Further, when there is a gap between the second member and the inner wall (side wall) of the defoaming tank (depressurization degassing tank) through which the molten glass G can pass, or the second member itself can pass through the molten glass G. In the case of a gap, it can be h ₂ ≧h. That is, the upper end of the second member may be higher than the liquid surface of the molten glass G.

The h ₂ system is preferably 0.4 to 0.9 h, and more preferably 0.5 to 0.8 h.

In the defoaming device (pressure degassing device) 10 of the present invention, the shape of the second member is not limited to the one shown.

For example, in the cross-sectional shape shown in Fig. 1, the second member 15 is provided perpendicularly to the horizontal direction, but the second member 15 may be inclined toward the downstream side or the upstream side. For example, when the inclination angle when the upper end of the second member 15 is inclined toward the downstream side is positive (when the inclination angle when the upper end of the second member 15 is inclined toward the upstream side is negative), the inclination angle β is -30°. In the range of +30°, the second member 15 may be inclined toward the downstream side or the upstream side, and the inclination angle β is preferably in the range of -15° to +15°, and is preferably -5° to +5°. The range is better.

Further, in the planar shape shown in FIG. 3, the second member 15 has a flat shape, but the planar shape of the second member 15 is not limited thereto. For example, as in the first member 14a shown in Fig. 10, the planar shape of the second member may be slightly V-shaped, and the first member 14b as shown in Fig. 11 may have a planar shape of the second member. shape. Further, the planar shape of the second member may be U-shaped.

In the defoaming device (pressure reducing defoaming device) 10 of the present invention, the distance d between the first member 14 and the second member 15 in the flow direction of the molten glass G is 50 to 400 mm. When the distance d between the first member 14 and the second member 15 is more than 400 mm, the effect of inducing the layer of the molten glass containing the residual bubbles to the surface layer of the molten glass cannot be sufficiently exhibited. When the distance d between the first member 14 and the second member 15 is less than 50 mm, the distance between the two members is too narrow, so that the flow of the molten glass G is hindered.

The distance d between the first member 14 and the second member 15 is preferably 80 to 350 mm, more preferably 100 to 300 mm, and still more preferably 130 to 250 mm.

When the length of the molten glass flow path of the defoaming tank (pressure reducing degassing tank) 11 is L, it is preferable to arrange the bubble floating mechanism so that the upstream end of the defoaming tank (pressure reducing degassing tank) 11 to the first member 14 The distance is 0.1L or more. The bubble floating mechanism is preferably such that the distance from the upstream end of the defoaming tank (pressure reducing degassing tank) 11 to the first member 14 is 0.2 L or more, and more preferably 0.4 to 0.9 L.

Further, the size of the defoaming tank (pressure reducing degassing tank) 11 can be appropriately selected depending on the shape of the defoaming device (pressure reducing defoaming device) 10 or the defoaming tank (pressure reducing degassing tank) 11 to be used, but Can be the following range.

The length of the molten glass flow path in the horizontal direction: 1~20m

Maximum width of molten glass flow path: 0.2~10m

In the case of a cylindrical defoaming tank (pressure reducing degassing tank) 11a having an elliptical cross section as shown in Fig. 4, one of the dimensions is as follows.

Horizontal length: 1~20m

Inner diameter (long diameter): 0.2~3m

In the defoaming device (pressure reducing defoaming device) of the present invention, two or more bubble floating mechanisms may be provided in the defoaming tank (pressure reducing degassing tank). When two or more bubble floating mechanisms are provided in the defoaming tank (pressure reducing degassing tank), the effect of inducing a layer of molten glass containing residual bubbles to the surface layer of molten glass is improved.

When two or more bubble floating mechanisms are provided in the defoaming tank (pressure reducing degassing tank), the distance between the bubble floating mechanisms, that is, the distance between the second member located on the upstream side and the first member located on the downstream side is 100 mm. the above. The distance between the bubble floating mechanisms is preferably 200 mm or more, and more preferably 400 mm or more. Further, the distance between the bubble floating mechanisms is preferably 1500 mm or less.

In the defoaming device (pressure degassing device) of the present invention, a member other than the bubble floating mechanism may be provided in the defoaming tank (pressure reducing defoaming tank). Fig. 16 is a view similar to Fig. 3, and Figs. 17 and 18 are cross-sectional views showing the defoaming tank (pressure reducing degassing tank) 11 shown in Fig. 16 taken along line C-C'. Further, the cross-sectional shape of the defoaming tank (pressure reducing degassing tank) 11 (11a) shown in Fig. 17 is elliptical, and the defoaming tank (pressure degassing tank) 11 (11b) shown in Fig. 18 The cross-sectional shape is a rectangle.

In the defoaming tank (pressure reducing degassing tank) 11 (11a, 11b) shown in Figs. 16 to 18, the third member 17 is provided on the downstream side of the second member 14. As described above, the second member 15 shown in the fifth and seventh embodiments is excellent in the effect of defoaming the residual bubbles in the molten glass in the central portion of the molten glass flow path, so that the second member is in a good form. However, there is a gap between the second member 15 and the inner wall (side wall) of the defoaming tank (depressurization degassing tank) 11 (11a, 11b) through which the molten glass G can pass, so that the layer of molten glass containing residual bubbles is When induced to the surface layer of the molten glass, it is not induced to the central portion of the molten glass flow path, but is induced to the side wall direction of the defoaming tank 11 (11a, 11b), and the residual bubbles floating up to the surface of the molten glass The distribution becomes uneven. When the third member 17 shown in FIGS. 16 to 18 is provided on the downstream side of the second member 15 shown in FIGS. 5 and 7, the second member 15 can be induced to the defoaming tank 11 (11a, 11b). The molten glass in the side wall direction is induced to the central portion of the molten glass flow path, and the residual bubbles floating up to the surface layer of the molten glass can be uniformly distributed.

When two or more bubble floating mechanisms are provided in the defoaming tank (pressure reducing degassing tank), two or more third members may be provided. That is, the third member can be provided on the downstream side of each of the second members. On the other hand, only one third member may be provided. That is, the third member can be provided on the downstream side of the second member on the most downstream side.

Since the first member 14 and the second member 15 (including the third member 17 when the third member 17 is provided) are in contact with the molten glass, it is necessary to use a material having excellent heat resistance and corrosion resistance to molten glass. Materials which can be used for the heat resistance of the first member 14 and the second member 15 and the corrosion resistance to the molten glass include platinum, a platinum alloy such as a platinum-gold alloy and a platinum-rhodium alloy, and a ceramic non-metallic inorganic material. , dense refractory, etc. Specific examples of the dense refractory include, for example, an alumina-based electroformed refractory, a zirconia-based electroformed refractory, and an electroformed refractory such as an alumina-zirconia-antimony electroforming refractory, and a dense oxidation. A compact refractory such as an aluminum refractory, a dense zirconia-lanthanum refractory, or a dense alumina-zirconia-lanthanum refractory.

The planar shape of the first member 14 and the second member 15 (including the third member 17 when the third member 17 is provided) and the cross-sectional shape cut by the line A-A' or the line B-B' are not included in the shape described above. Particularly limited, it may be a plate member or a block member.

The other components of the defoaming device (pressure degassing device) 10 that is in contact with the molten glass, that is, the defoaming tank (pressure reducing degassing tank) 11, the riser tube 12, and the downcomer 13 also need to use heat resistance and the molten glass. As the material having good corrosion resistance, the above-mentioned platinum, platinum alloy, ceramic non-metallic inorganic material, dense refractory or the like can be used.

Example

Hereinafter, the present invention will be described in further detail by way of examples and comparative examples, but the invention is not limited thereto.

The clarification effect of the molten glass in the vacuum degassing tank was evaluated by simulation. In the simulation, the motion of bubbles in the molten glass was analyzed by a computer program using the finite element method. In addition, the bubble is randomly generated at the lower end of the riser, and the molten glass has a temperature of 1430 ° C and a viscosity of 100 Pa. s to calculate.

The vacuum degassing tank was evaluated by having an elliptical cross section as shown in Fig. 4 . The size of the vacuum degassing tank and the liquid level of the molten glass are as follows.

The length of the molten glass flow path is L: 9m

The maximum value of the inner diameter of the molten glass flow path in the horizontal direction is W ₁ : 480 mm

The height of the decompression degassing tank D: 320mm

Liquid level of molten glass: 250mm

The molten glass which passes through the degassing degassing tank is expected as follows.

Glass: Alkali-free glass for liquid crystal display (LCD) (AN100, Asahi Glass Co., Ltd.)

Flow rate: 70 tons / day

Temperature (average) when degassing the tank by pressure: 1430 ° C

Viscosity when degassing the tank by pressure reduction: 100Pa. s

Density when degassing the tank by pressure reduction: 2380 kg/m ³

(Example 1)

The vacuum degassing tank having an elliptical cross section is the first member 14 shown in Figs. 3 and 4 for the first member, and the second member 15 shown in Fig. 3 and Fig. 5 for the second member. The situation is to evaluate the defoaming performance. The dimensions of the first member 14 and the second member 15 and the installation positions in the molten glass flow path are as follows.

[1st member 14]

The height of the bottom surface of the defoaming tank to the lower end of the first member h ₁ : 125 mm

Height (thickness) of the first member H ₁ : 125 mm

Distance from the upstream end of the molten glass flow path: 4.5 m

[2nd member 15]

Height of the second member h ₂ : 178 mm

The maximum width of the second member W ₂ : 200 mm

Distance d between the first member and the second member: 175 mm

For the defoaming performance, the absolute pressure (P _th ) at which 10,000 bubbles having a diameter of 100 μm were defoamed, and the distance from the upstream end of the defoaming tank (the longest floating distance) at which the bubble finally floated were evaluated. The larger the value of P _th , the better the defoaming performance. Moreover, the smaller the longest floating distance, the better the defoaming performance. The results are shown in Table 1. Further, in Table 1, the pressure difference between P _th and P ₀ and the longest floating distance are shown. In the above P ₀ system, the absolute pressure of 10,000 bubbles having a diameter of 100 μm can be deactivated when the second member is not provided. Comparative Example 1 is an example in which the second member is not provided.

(Example 2)

The second member was tilted, and the same procedure as in the first embodiment was carried out. The second member is inclined at an upper end portion thereof toward the downstream side, and is disposed to be inclined by 61° with respect to the vertical direction (inclination by 29° with respect to the horizontal direction).

(Example 3)

In the same manner as in the first embodiment, the first member is the first member 14a shown in Fig. 10 . The height h ₁ of the bottom surface of the defoaming tank to the lower end of the first member was 85 mm, the height (thickness) of the first member was 165 mm, and the distance from the upstream end of the molten glass flow path to the upstream end of the first member was 4.5 m. In Fig. 10, L ₁ is 524 mm and L ₂ is 498 mm. The distance d between the end portion on the downstream side of the first member and the second member was 627 mm.

(Example 4)

The first member was the first member 14b shown in Fig. 11, and was carried out in the same manner as in the first embodiment. The height h ₁ of the bottom surface of the defoaming tank to the lower end of the first member was 125 mm, the height (thickness) of the first member was 125 mm, and the distance from the upstream end of the molten glass flow path to the upstream end of the first member was 4.5 m. In Fig. 11, L ₃ is 200 mm and L ₄ is 188 mm. The distance d between the end portion on the downstream side of the first member and the second member was 150 mm.

Then, in the same manner as in the first embodiment, the first member is fixed to the first member 14 shown in FIG. 3 and FIG. 4, and the second member is changed in the following two items, and the same as in the first embodiment. Implementation.

(Example 5)

Second member: the second member 15a shown in Fig. 12

Height of the second member h ₂ : 178 mm

H _{2 in} Fig. 12 is 75 mm, and L ₅ is 200 mm. The distance d between the end portion on the downstream side of the first member and the second member was 263 mm.

(Example 6)

Second member: the second member 15b shown in Fig. 13

Height of the second member h ₂ : 178 mm

H _{3 in} Fig. 13 is 93 mm. The distance d between the end portion on the downstream side of the first member and the second member was 263 mm.

The results are shown in Table 2. In addition, Table 2 also shows the results of Example 1 for comparison.

(Example 7)

In the first embodiment, W _{2 was} changed to three items of 120 mm, 200 mm, and 280 mm. The values of P _th -P ₀ were 1.1 kPa (225 mm), 1.4 kPa (375 mm), and 1.3 kPa (525 mm), respectively.

(Examples 8 to 13 and Comparative Examples 2 to 3)

The h _{2 in} the structure of Example 1 was changed as shown in the following table, and was carried out as Examples 8 to 13, Comparative Example 2, and Comparative Example 3. The results are shown in Table 3.

Further, although the height h ₁ of the bottom surface of the defoaming groove in the structure of the first embodiment to the lower end of the first member was changed to three items of 125 mm, 105 mm, and 85 mm, the value of P _th -P ₀ was due to h _{1 .} The difference caused by the change was 0.1 kPa or less, which did not affect the clarification effect of the molten glass.

(Examples 14 to 20)

In the first embodiment, the distance d between the first member and the second member was changed as shown in Table 4, and was carried out as Examples 14 to 20. The results are shown in Table 4.

(Example 21)

The evaluation was carried out for the vacuum degassing tank as shown in Fig. 6 in which the cross section was rectangular. The size of the vacuum degassing tank and the liquid level of the molten glass are as follows.

The length of the molten glass flow path is L: 4.0m

The maximum value of the inner diameter of the molten glass flow path in the horizontal direction is W ₁ : 975 mm

The height of the decompression degassing tank D: 600mm

Liquid level of molten glass: 200mm

The clarification effect of the molten glass was evaluated in the case where the first member was the first member 14 shown in FIGS. 3 and 6 and the second member was the second member 15 shown in FIGS. 3 and 7. The dimensions of the first member 14 and the second member 15 and the installation positions in the molten glass flow path are as follows.

First member 14

The height of the bottom surface of the defoaming tank to the lower end of the first member h ₁ : 100 mm

Height (thickness) of the first member: 100 mm

Distance from the upstream end of the molten glass flow path: 2.0 m

Second member 15

Height of the second member h ₂ : 140 mm

The maximum width of the second member W ₂ : 459 mm

Distance d between the first member and the second member: 181 mm

With respect to the clarifying effect of the molten glass, the absolute pressure (P _th ) at which 10,000 bubbles of 100 μm in diameter were defoamed, and the distance from the upstream end of the defoaming tank (the longest floating distance) at which the bubble finally floated were evaluated. The results are shown in Table 5. In addition, in Table 5, the pressure difference of P _th and P ₀ ' is shown. The above P ₀ ' is an absolute pressure at which 10,000 bubbles of 100 μm in diameter can be defoamed when the second member is not provided.

As described above, according to the defoaming device of the present invention, the clarification effect can be improved without changing the conditions of the clarification procedure such as lowering the degree of pressure reduction or increasing the temperature of the molten glass.

Industrial use possibility

The defoaming device of the present invention can be used to remove air bubbles from the molten glass.

In addition, all the contents of the patent specification, the patent application scope, the drawings and the abstract of the Japanese Patent Application No. 2008-150557, filed on Jun. 9, 2008, the disclosure of .

10. . . Defoaming device (pressure degassing device)

11. . . Defoaming tank (pressure degassing tank)

11a. . . Defoaming tank (pressure degassing tank)

11b. . . Defoaming tank (pressure degassing tank)

11c. . . Defoaming tank (pressure degassing tank)

12. . . Riser

13. . . Drop tube

14. . . First member

14a. . . First member

14b. . . First member

15‧‧‧2nd member

15a‧‧‧2nd component

15b‧‧‧2nd component

16‧‧‧ gap

17‧‧‧3rd building block

200‧‧‧melting tank

220‧‧‧ upstream trough

240‧‧‧Downstream trough

G‧‧‧ molten glass

A-A’‧‧‧ line

B-B’‧‧‧ line

C-C’‧‧‧ line

D‧‧‧ Height

D‧‧‧distance

H ₁ ‧‧‧ Height

H ₂ ‧‧‧ Height

H ₃ ‧‧‧ Height

h ₁ ‧‧‧height

h ₂ ‧‧‧height

L ₁ ‧‧‧ length

L ₂ ‧‧‧ length

L ₃ ‧‧‧ length

L ₄ ‧‧‧ length

L ₅ ‧‧‧ length

Fig. 1 is a cross-sectional view showing a structural example of one of the defoaming devices for molten glass of the present invention.

Fig. 2 is a perspective view showing a cross section of a portion of the defoaming device 10 shown in Fig. 1 excised.

Fig. 3 is a plan view of the defoaming device 10 shown in Fig. 1.

Fig. 4 is a cross-sectional view showing a line A-A' of the defoaming tank (cross-sectional ellipse) 11 shown in Fig. 1.

Fig. 5 is a cross-sectional view showing a cross section taken along line B-B' of the defoaming tank (cross-sectional elliptical shape) 11 shown in Fig. 1.

Fig. 6 is a cross-sectional view showing a cross section taken along line A-A' of the defoaming tank (section rectangle) 11 shown in Fig. 1.

Fig. 7 is a cross-sectional view showing a cross section taken along the line B-B' of the defoaming tank (cross-sectional rectangle) 11 shown in Fig. 1.

Fig. 8 is a cross-sectional view showing a cross section taken along the line A-A' of the defoaming tank (cross-section trapezoid) 11 shown in Fig. 1.

Fig. 9 is a cross-sectional view showing a cross section taken along the line B-B' of the defoaming tank (cross-section trapezoid) 11 shown in Fig. 1.

Fig. 10 is a plan view showing the planar shape of the first member into a substantially V-shaped defoaming device 10.

Fig. 11 is a plan view of the defoaming device 10 in which the planar shape of the first member is formed into a stepped shape (convex shape).

Fig. 12 is a cross-sectional view showing a cross section taken along the line B-B' of the defoaming groove (cross-sectional elliptical shape) 11 of the second member formed in a T shape.

Fig. 13 is a cross-sectional view showing a cross section taken along the line B-B' of the defoaming groove (cross-sectional elliptical shape) 11 of the second member formed in a strip shape.

Fig. 14 is a cross-sectional view showing a cross section taken along the line B-B' of the defoaming groove (cross-sectional rectangle) 11 of the second member formed in a T shape.

Fig. 15 is a cross-sectional view showing a cross section taken along the line B-B' of the defoaming groove (cross-sectional rectangle) 11 of the second member formed in a strip shape.

Fig. 16 is a plan view showing the defoaming device 10 of the molten glass of the present invention, in which the third member 17 is disposed on the downstream side of the second member 15.

Fig. 17 is a cross-sectional view taken along the line C-C' of the section elliptical defoaming groove 11.

Fig. 18 is a cross-sectional view showing a section taken along the line C-C' of the rectangular section defoaming groove 11.

10. . . Defoaming device (pressure degassing device)

11. . . Defoaming tank (pressure degassing tank)

12. . . Riser

13. . . Drop tube

14. . . First member

15. . . Second member

200. . . Melting tank

220. . . Upstream slot

240. . . Downstream slot

G. . . Molten glass

d. . . distance

h ₁ . . . height

h ₂ . . . height

A-A’. . . line

B-B’. . . line

Claims (11)

A defoaming device for molten glass, comprising a defoaming tank having an inlet and a discharge port of molten glass, wherein a bubble floating mechanism having a first member and a second member is provided in the defoaming tank; The first member is attached to the inner wall of the defoaming tank, and at least a part thereof is immersed in the molten glass, and is disposed so as to be disposed across the entire width direction of the flow path of the molten glass of the defoaming tank. The member is attached to the inner wall of the defoaming tank, and extends upward from the bottom surface side of the defoaming tank, and the first member and the second member are disposed so as to satisfy the following (1) to (3). (1) The first member is located on the upstream side in the flow direction of the molten glass with respect to the second member, and (2) the distance between the first member and the second member in the flow direction of the molten glass is 50. (3) when the height of the bottom surface of the defoaming tank to the lower end of the first member is h ₁ and the height of the bottom surface of the defoaming tank to the upper end of the second member is h ₂ , the relationship is satisfied. Formula h ₁ ≦h ₂ . A defoaming device for molten glass according to the first aspect of the invention, wherein the second member is provided with a gap through which the molten glass can pass. A defoaming device for molten glass according to the first aspect of the invention, wherein the inner wall of the defoaming tank and the second member have a gap through which the molten glass can pass. The defoaming device for molten glass according to the third aspect of the invention, wherein the maximum value of the inner diameter of the defoaming groove in the horizontal direction is W ₁ and the maximum value of the lateral width of the second member is W ₂ When the relationship is satisfied, 0.2 ≦ W ₂ /W ₁ ≦ 0.9. The defoaming device for molten glass according to any one of claims 1 to 4, wherein a height h ₁ of a bottom surface of the defoaming tank to a lower end of the first member is 70 to 250 mm. The defoaming device for molten glass according to any one of claims 1 to 4, wherein the planar shape of the first member satisfies the following formula: w ₁ <w ₂ (wherein w ₁ is in the molten glass The lateral width of the first member in the upstream side in the flow direction, and w ₂ is the lateral width of the first member in the downstream side in the flow direction of the molten glass. The defoaming device for molten glass according to the fifth aspect of the invention, wherein the planar shape of the first member satisfies the following formula: w ₁ <w ₂ (wherein w ₁ is in the upstream side of the flow direction of the molten glass The lateral width of the first member is w ₂ in the lateral width of the first member in the downstream side in the flow direction of the molten glass. The defoaming device for molten glass according to any one of claims 1 to 4, wherein the bubble removing tank is provided with two or more bubble floating mechanisms. The defoaming device for molten glass according to claim 5, wherein the bubble removing tank is provided with two or more bubble floating mechanisms. The defoaming device for molten glass according to claim 6, wherein the bubble removing tank is provided with two or more bubble floating mechanisms. The defoaming device for molten glass according to claim 7, wherein the bubble removing tank is provided with two or more bubble floating mechanisms.