WO2012091133A1

WO2012091133A1 - Clarification tank, glass melting furnace, molten glass production method, glassware production method and glassware production device

Info

Publication number: WO2012091133A1
Application number: PCT/JP2011/080497
Authority: WO
Inventors: 整長野; 清太宮崎; 徹也山本; 匡博津田
Original assignee: 旭硝子株式会社
Priority date: 2010-12-28
Filing date: 2011-12-28
Publication date: 2012-07-05
Also published as: KR20140001886A; JPWO2012091133A1; CN103269986A

Abstract

The purpose of the present invention is to provide a clarification tank provided with a first clarification tank, a second clarification tank and a cooling tank. The present invention pertains to a clarification tank provided with: a first clarification tank provided with a first molten glass flow channel partitioned off by a first bottom wall and first side walls disposed on both sides of the first bottom wall, a drain section provided in the bottom wall on the downstream side of the first molten glass flow channel, and a molten glass heating means, wherein the length of the first molten glass flow channel is greater than the height of the first side walls; a second clarification tank which is contiguous with the first clarification tank and is provided with a second molten glass flow channel partitioned off by a second bottom wall and second side walls disposed on both sides of the second bottom wall, wherein the shape of the flow channel is such that the molten glass achieves a uniflow state; and a cooling tank which is contiguous with the second clarification tank and is provided with a third molten glass flow channel partitioned off by a third bottom wall and third side walls disposed on both sides of the third bottom wall.

Description

Clarification tank, glass melting furnace, molten glass manufacturing method, glass product manufacturing method, and glass product manufacturing apparatus

The present invention relates to a clarification tank comprising a first clarification tank, a second clarification tank and a cooling tank for producing molten glass, a glass melting furnace comprising the same, a glass product production apparatus, and a clarification tank. The present invention relates to a method for producing a molten glass and a method for producing a glass product.

As an example of a method for producing a glass plate, a glass production apparatus provided with a melting tank, a clarification tank, and a molding apparatus is used, a glass raw material is melted in the melting tank, and the obtained molten glass is defoamed in the clarification tank, A float method is known in which a uniform molten glass with a small amount of glass is sent to a forming apparatus equipped with a float bath to form a glass plate.
A flow path of molten glass is formed in a clarification tank used in the float process, and this flow path is generally configured by assembling a plurality of refractories such as refractory bricks.
In addition, when the glass raw material is melted in the melting tank, a gas that inevitably forms bubbles in the molten glass is generated during the reaction of the raw material components. It is necessary to obtain molten glass and send this molten glass to a molding apparatus for the next step.
The general fining of molten glass is due to chemical fining, and a fining agent for this purpose is added in advance to the glass raw material and introduced into the molten glass. The fining agent is a polyvalent oxide or the like that is reduced at high temperatures (ie, the fining agent loses oxygen) and is oxidized (bonded to oxygen) at low temperatures. Oxygen released by the fining agent increases bubbles in the molten glass, and when the grown bubbles rise to the surface of the molten glass, they are broken and defoamed.

In such a background, as a glass melting facility, a melting tank for melting a batch raw material to form a molten glass, a clarification tank having a shallow molten glass flow path connected to the melting tank, and this clarification tank There is known a glass melting apparatus having a structure equipped with a homogenization tank connected to (see Patent Document 1 and Patent Document 2).

Japanese Unexamined Patent Publication No. Sho 61-132565 US Patent Publication No. 6085551

In a glass melting furnace equipped with a conventional melting tank and clarification tank, the glass melted in the melting tank enters the clarification tank, and part of it returns to the melting tank by convection. During the circulation between the melting tank and the clarification tank, the clarification of the glass proceeds and the molten glass is clarified. Here, the clarified glass flows into the downstream molding process.

In this type of clarification tank, a clarification tank called a high-temperature clarification type is known. In this high-temperature clarification type clarification tank, in order to efficiently remove bubbles, the temperature of the molten glass flowing through the clarification tank is set as high as possible under the conditions where re-foaming is not performed, thereby lowering the viscosity of the molten glass and increasing the bubble growth rate. However, by increasing the bubble diameter, the bubble rising speed is increased so that the bubble can be removed.
However, in the recently requested glass, higher quality glass is required, and the clarification tank structure that can more effectively defoam the molten glass in a glass melting furnace equipped with a melting tank and a clarification tank. Is desired.
Moreover, when producing molten glass using a high-temperature clarification type clarification tank, the temperature of the molten glass flowing through the clarification tank is set as high as possible, so that a large amount of energy is naturally consumed. From the recent demand for energy saving, a clarification tank capable of energy saving operation while satisfying the bubble removal performance is desired.
Further, in order to perform high-temperature clarification, usually, most of the glass flow path is composed of a refractory metal made of a rare metal having a fire resistance such as platinum or a platinum alloy. For this reason, the clarification tank that performs high-temperature clarification is considered to be about 20 to 50 tons per day at most. As far as the present inventors know, there is no single clarification tank for high-temperature clarification exceeding 100 tons of Nissan. Therefore, a technique capable of realizing a low-cost or large-scale glass melting furnace by taking advantage of high-temperature clarification is desired.
In the apparatus for manufacturing a molten glass having a high melting point described in Patent Document 2, a so-called “refining bank” is formed in a region where glass material is clarified after melting. Further, in the “refining bank”, the molten glass is heated by a burner at the top. For this reason, it is difficult to produce a large-capacity molten glass, and it is considered that the energy saving property is not high.

An object of the present invention is to provide a clarification tank that can efficiently defoam to achieve the above-described needs and can be constructed at low cost or on a large scale with improved energy saving.
Moreover, this invention aims at provision of the manufacturing method and manufacturing apparatus of a molten glass which can be provided with the said clarification tank and can provide a high quality molten glass and glassware, and the manufacturing method of glassware.

As a result of earnest research, the present inventors are characterized by a high-temperature clarification that can be produced while maintaining the quality of molten glass, even if refractory bricks are mainly used, in order to achieve the above object. I came up with the structure of the clarification tank. Thereby, a low-cost or large-scale clarification tank can be realized.
The present invention provides a first molten glass flow path defined by a first bottom wall part and first side wall parts on both sides thereof, and a bottom wall part downstream of the first molten glass flow path. A first clarification tank comprising a drain-out portion provided and a means for heating molten glass, wherein a length of a flow path of the first molten glass is larger than a height of the first side wall portion; The second molten glass flow path is provided following the clarification tank, and is partitioned by the second bottom wall portion and the second side wall portions on both sides thereof, and has a flow channel shape in which the molten glass is in a uniflow state. A cooling tank provided with a second clarification tank and a third molten glass flow path which is provided following the second clarification tank and is partitioned by a third bottom wall portion and third side wall portions on both sides thereof. And a clarification tank provided with.
In the clarification tank of the present invention, in the flow path of the second molten glass, the width perpendicular to the flow path direction of the second bottom wall portion may be larger than the height of the second side wall portion.
In the clarification tank according to the present invention, when the flow path shape of the second molten glass is Gr / Glashof number of the molten glass flowing through the flow path and Reynolds number is Re, Gr / It is preferable to set so as to satisfy Re2 <11420.
In the clarification tank according to the present invention, the heating means of the first clarification tank is a plurality of electrodes, and in the second clarification tank, the second bottom wall part and the second side wall part in the second side wall part. It is preferable that the molten glass flow path is made of refractory bricks, and an inner surface cover made of a heat-resistant metal that covers the refractory bricks on the flow path side is provided.

In the clarification tank according to the present invention, the heating means of the first clarification tank is a burner, and in the first and second clarification tanks, the molten glass flow paths in the bottom wall part and both side wall parts are made of refractory bricks. It is preferable that an inner surface cover made of a heat-resistant metal that covers the refractory brick on the flow path side is provided.
In the clarification tank according to the present invention, the flow length of the flow path of the molten glass is 10 to 15 m, the flow length of the second molten glass is 4 to 14 m, 100 to 1000 tons / day.
In the clarification tank of the present invention, a first step portion higher than the first bottom wall portion may be formed at the most upstream end of the flow path of the first molten glass.
In the clarification tank of the present invention, a second step portion higher than the second bottom wall portion may be formed at the most upstream end of the flow path of the second molten glass.
In the clarification tank of the present invention, a first convex portion may be formed from a corner portion of the second side wall portion and the second bottom wall portion on the downstream side of the flow path of the second molten glass.
In the clarification tank of the present invention, in the flow path of the second molten glass, the second convex portion is further upstream than the formation position of the first convex portion, and the second convex portion is the second side wall portion and the second bottom. You may form from the corner with a wall part.
In the fining tank of the present invention, the inner surface cover includes a plurality of cover assemblies arranged along the flow direction of the molten glass so as to cover the molten glass flow channel side of the bottom wall and the side wall. The assembly includes a bottom wall plate that covers the bottom wall portion, a side wall plate that covers the side wall portion, and a first cover plate that covers a butting region of cover assemblies disposed along the flow path. Also good.
In the clarification tank of the present invention, the cooling tank may be provided with an inner surface cover made of a heat-resistant metal that covers the molten glass flow path side in the third bottom wall portion and both third side wall portions.
In the clarification tank of the present invention, the heating means provided in the first clarification tank comprises a plurality of electrodes erected in the first clarification tank, and these electrodes are along the flow direction of the molten glass. A plurality of electrodes arranged in rows and columns at predetermined intervals so as to form a matrix and arranged in a line along the flow path direction of the molten glass may be multiphase AC electrodes.

This invention provides the glass melting furnace which has the clarification tank in any one of the above, and was equipped with the melting tank in the upstream of the flow direction of the molten glass of the said clarification tank.
The present invention includes a step of melting a glass raw material in a melting tank using the glass melting furnace described above, and clarification by heating the molten glass that has come out of the melting tank in a first clarification tank. The step of discharging the heterogeneous substrate generated in the first clarification tank from the bottom on the downstream side of the clarification tank, the step of clarifying the flow of the molten glass in the second clarification tank as a uniflow state, and the second by the cooling tank And a step of cooling the molten glass derived from the clarification tank.
In the method for producing molten glass of the present invention, the flow rate of molten glass and the flow rate of molten glass are such that the uniflow state satisfies Gr / Re ² <11420, where Gr is the graphhof number of the molten glass and Re is the Reynolds number. You may set the temperature change of the molten glass in the entrance and exit of a path | route, and the depth of a molten glass.
The molten glass manufacturing method of the present invention may not heat the molten glass in the second clarification tank. This means that it is not necessary to provide a heating means as a suitable range of the second clarification tank of the present invention.
In the method for producing molten glass according to the present invention, the heating in the first clarification tank makes the temperature on the downstream end side of the first clarification tank the highest with respect to the temperature of the molten glass flowing in the first clarification tank. It is preferable to be performed as follows.

The present invention includes a step of producing the molten glass described above, a step of forming the molten glass after cooling the molten glass to its glass forming temperature region, and a step of gradually cooling the glass after forming. A method for producing a glass product is provided.
The present invention provides an apparatus for producing a glass product, comprising the glass melting furnace described above, a molding means for molding the molten glass produced by the glass melting furnace, and a slow cooling means for gradually cooling the glass after molding. I will provide a.

The present invention provides a first molten glass flow path defined by a first bottom wall part and first side wall parts on both sides thereof, and a bottom wall part downstream of the first molten glass flow path. A first clarification tank comprising a drain-out portion provided and a means for heating molten glass, wherein a length of a flow path of the first molten glass is larger than a height of the first side wall portion; The second molten glass flow path is provided following the clarification tank, and is partitioned by the second bottom wall portion and the second side wall portions on both sides thereof, and has a flow channel shape in which the molten glass is in a uniflow state. A cooling tank provided with a second clarification tank and a third molten glass flow path which is provided following the second clarification tank and is partitioned by a third bottom wall portion and third side wall portions on both sides thereof. The bubbles remaining in the first clarification tank can be removed in the second clarification tank. Effective from the bottom on the downstream side of the first clarification tank, the heterogeneous base that elutes from the refractory bricks that tend to occur when using a high-temperature clarified refractory brick flow path in the first clarification tank It can be discharged efficiently, and it is possible to further defoam and maintain the quality of the molten glass. Further, according to the present invention, the clarification tank can be made large-scale, and the amount of heat brought in from the molten glass can be increased, so that the second clarification tank can be provided with no heating means. Furthermore, in the second clarification tank, the clarification treatment can be performed without heating, so that an energy saving operation is possible, and the energy saving operation can be performed more than the structure provided with the heating means up to the second clarification tank.
Since the molten glass flowing through the flow path in the second clarification tank can be flowed in a uniflow state in one direction from the upstream side to the downstream side, the bubbles can be further removed under conditions advantageous for the bubble removal. Specifically, since there is no circulating flow because it can flow in a uniflow state, the low temperature molten glass is prevented from returning to the upstream side of the high temperature, and heat loss due to reheating the first fining tank. Can be eliminated.

Depending on the heating means of the first clarification tank, only the molten glass flow path of the second clarification tank or the molten glass flow path of the first and second clarification tanks is made of refractory bricks, and the refractory bricks are heat resistant. By covering with metal, most of the molten glass flow path of the first clarification tank and the second clarification tank does not need to be mainly composed of platinum or platinum alloy, realizing a low-cost or large-scale glass melting furnace Is possible.
When adopting a configuration in which a heat-resistant metal inner cover is provided in the second clarification tank, when aiming for a high clarification effect by introducing molten glass at the highest temperature in the first clarification tank to the second clarification tank Even so, the influence on the furnace material constituting the second clarification tank is reduced, and problems such as damage to the furnace material and elution of foreign components can be avoided in the second clarification tank.

Using the first clarification tank and the second clarification tank according to the present invention, performing the convection heating as high temperature as possible by the heating means in the first clarification tank, discharging the foreign material that leaks from the foam removal and refractory bricks, Since the molten glass is clarified by a two-stage process of clarification in a flow in a fixed direction in the second clarification tank, efficient defoaming can be realized by energy saving operation. For this reason, it is possible to provide a high-quality molten glass and glass product free from bubbles and containing few impurities.

Drawing 1 is a lineblock diagram showing an example of the manufacture device of the glassware provided with the clarification tank concerning a 1st embodiment of the present invention. FIG. 2 is a schematic plan view showing the main part of the manufacturing apparatus. 3 shows a cross-sectional structure of the second clarification tank shown in FIG. 1, FIG. 3 (a) is a cross-sectional view, and FIG. 3 (b) is a partially enlarged cross-sectional view of the clarification tank. FIG. 4 is a block diagram showing an example of an inner surface cover disposed inside the clarification tank. FIG. 5 is a plan view showing an example of an inner surface cover arranged inside the clarification tank. FIG. 6 is a partial cross-sectional view showing an example of an inner surface cover disposed in the clarification tank. FIG. 7 is an exploded perspective view showing an example of an inner surface cover arranged inside the clarification tank. FIG. 8 is a flowchart showing an example of a glass product manufacturing process according to the present invention. FIG. 9: is a block diagram which shows an example of the manufacturing apparatus of the glass product provided with the clarification tank based on 2nd Embodiment of this invention. FIG. 10 is a schematic plan view showing the main part of the glass product manufacturing apparatus shown in FIG. FIG. 11 shows an example of a convex portion formed on the bottom wall portion of the second clarification tank in the glass product manufacturing apparatus shown in FIG. 9, and FIG. FIG. 11B is a perspective view showing a second example of the first convex portion, and FIG. 11C is a perspective view showing a third example of the first convex portion. 11 (D) is a perspective view showing a fourth example of the first convex part, FIG. 11 (E) is a perspective view showing a fifth example of the first convex part, and FIG. 11 (F) is the first example. The perspective view which shows the example of a convex part and a 2nd convex part. FIG. 12 is a partial cross-sectional view showing a second example of the inner surface cover disposed inside the clarification tank. FIG. 13: is a front view which shows the 3rd example of the inner surface cover arrange | positioned inside the clarification tank. FIG. 14 is a perspective view showing a fourth example of the inner surface cover disposed in the clarification tank. FIG. 15: is a block diagram which shows an example of the manufacturing apparatus of the glass product provided with the clarification tank based on 3rd Embodiment of this invention.

Hereinafter, a clarification tank according to the present invention, and a glass melting furnace and a method for manufacturing a molten glass including the same, and a method for manufacturing a glass product and a manufacturing apparatus will be described with reference to the drawings. The present invention is not limited to the embodiment. Moreover, in each figure shown below, about the reduced scale of each component, it simplifies and shows so that it may be easy to grasp | ascertain in the case of illustration.
FIG. 1 is a configuration diagram schematically showing one embodiment of a molten glass production apparatus provided with a clarification tank according to the present invention, and FIG. 2 is a plan view of the main part of the apparatus.
The glass product manufacturing apparatus 1 of the present embodiment includes a melting tank 2 for melting a glass raw material to produce molten glass, a first clarification tank 3 sequentially installed on the downstream side of the melting tank 2, A second clarification tank 4, a cooling tank 5, and a molding device 6 are provided. In the present embodiment, a molten glass clarification tank 7 is constituted by the first clarification tank 3, the second clarification tank 4, and the cooling tank 5, and a glass melting furnace is formed by the melting tank 2 and the clarification tank 7. 14 is configured.

The melting tank 2 of the present embodiment is provided with a glass raw material charging part (not shown) on one side and a connecting part to the first clarification tank 3 on the opposite side. It is provided as a tank for preparing molten glass by melting the charged glass raw material using a heating device such as a burner. In addition, the burner provided in the melting tank 2 is attached to the side wall of the melting tank 2 so as to blow out the combustion flame, and is attached to the ceiling wall of the melting tank 2 downward. It is also possible to use a burner of a type that blows out, or in the air melting method in which a mixed powder raw material obtained by mixing glass raw material powder in a predetermined ratio is directly blown out of the burner to form molten glass in a high-temperature gas phase atmosphere. It may be a burner for a granulated body. Furthermore, the melting tank 2 may be a device that is energized and heated using electrodes.

The first clarification tank 3 to which the melting tank 2 of this embodiment is connected is elongated and has a substantially constant width in plan view, and the flow path of the first clarification tank 3 as shown in FIGS. 1 and 2. The length in the direction, that is, the length of the flow path of the first molten glass is configured to be larger than the height of the side wall portion of the melting tank, and the first bottom wall portion 3a and the first side wall portions 3b on both sides thereof. And the ceiling portion 3c. In other words, the first clarification tank of the present invention is different from a so-called rising type clarification tank in which the clarification has a considerably deep tank structure at the bottom. The region defined by the first bottom wall portion 3a and the first side wall portions 3b on both sides of the first clarification tank 3 is a flow path R1 of molten glass, and the two-dot chain line GH in FIG. Molten glass is supplied to the first clarification tank 3 so as to be at the liquid level of the glass. A plurality of electrodes 8 are erected on the first bottom wall portion 3a of the first clarification tank 3 at a predetermined interval, and the amount of electricity supplied to these

electrodes

8, 8. It can be heated to the desired temperature.

In the first clarification tank 3, a plurality of refractory bricks (refractories) are joined via joints to form a bottom wall portion 3a, a side wall portion 3b, and a ceiling portion 3c, and the shapes shown in FIGS. 1 and 2 as a whole. It is comprised so that it may become the general shape as a tank of. In FIG. 1 and FIG. 2, the thickness of the firebrick which comprises the 1st clarification tank 3 is abbreviate | omitted, and only the outline of the tank is shown. Thus, the cost which concerns on the structure of a molten glass flow path can be reduced by making a molten glass flow path mainly from a refractory brick.
In the first clarification tank 3, an inlet side step (that is, a first step) 3d that is raised by one step from the bottom wall portion 3a is formed on the upstream end side, that is, the portion on the melting tank 2 side. In the clarification tank 3, a plurality of drain-out drain portions 3e are formed in the width direction of the first clarification tank 3 at the downstream end side, that is, on the second clarification tank 4 side, one step lower than the bottom wall 3a. ing. Since the first clarification tank 3 has a high temperature, if it is made of refractory brick, the composition component of the refractory brick may elute into the molten glass and become a heterogeneous base material of the molten glass, but this drain-out portion 3e is provided. In this way, it is possible to discharge such a heterogeneous substrate and use refractory bricks.
The introduction port (that is, the inlet portion) 3f of the first clarification tank 3 is formed shallower than the other part of the first clarification tank 3 by the amount of the entrance-side step 3d. Further, the downstream end side of the first clarification tank 3 is partitioned by a partition wall 3g that rises vertically, and the outlet port is a portion where the depth of the flow path R of the molten glass is shallowed on the upper end side of the partition wall 3g. A second clarification tank 4 is connected via 3h.

The second clarification tank 4 is long and narrow in plan view, and is configured as a tank that is shallower than the horizontal width as shown in FIGS. 1 and 2. It is comprised from the 2nd side wall part 4b and the ceiling part 4c of both sides. A region defined by the second bottom wall portion 4a of the second clarification tank 4 and the second side wall portions 4b on both sides is a flow path R2 of molten glass, and a two-dot chain line GH in FIG. Molten glass G is supplied to the second clarification tank 4 so as to be at the liquid level. In the flow path of the second clarification tank 3, that is, the flow path of the first molten glass, the width perpendicular to the flow path direction of the second bottom wall portion is configured to be larger than the height of the side wall portion of the melting tank. ing.
In FIG. 2, the width of the second clarification tank is constant, but the width of the second clarification tank is wider than the width of the first clarification tank, and the depth is further reduced, thereby clarifying the effect. Can be raised.
In the second clarification tank 4, a plurality of refractory bricks are joined via joints to form a bottom wall part 4a, a side wall part 4b, and a ceiling part 4c, and the tank as shown in FIGS. 1, 2, and 3 as a whole. It is comprised so that it may become the general form. 1 and 2, the thickness of the refractory brick (refractory) constituting the second clarification tank 4 is abbreviated, only the outline of the tank is shown, and FIG. 3 shows the bottom wall 4a and the side wall as an example. 4b and the thickness of the refractory bricks that compose them.

The size of the refractory bricks constituting the bottom wall portion 4a and the side wall portion 4b is arbitrary, and the number and size of the refractory bricks to be applied can be freely selected according to the size of the bottom wall portion 4a and the side wall portion 4b. can do. For example, the bottom wall portion 4a and the side wall portion 4b shown in FIG. 3A may have a multilayer structure with a plurality of refractory bricks. In the structure shown in FIG. 3, for simplification of explanation, only one refractory brick 4d constituting the bottom wall portion 4a is shown, and two refractory bricks constituting the side wall portion 4b are stacked in the height direction of the side wall portion 4b. As an example. For example, FIG. 3 shows a structure in which the first refractory brick 4e is arranged on the bottom side of the side wall 4b and the second refractory brick 4f is stacked thereon. In FIG. 3, a water cooling jacket 50 is provided on the outer side (that is, the back side) of the refractory brick 4f that constitutes the upper end of the side wall 4b. Since the structure of the water-cooling jacket 50 is a known configuration, the detailed description is omitted and the detailed structure is also omitted in FIG. As an example, the water-cooling jacket 50 can employ a structure in which a circulation channel is constituted by an outgoing tube and a return tube, and cooling is performed by flowing cooling water through the circulation channel.
In the second clarification tank 4, an upstream side, that is, a part on the first clarification tank 3 side is formed with an inlet side step (that is, a second step) 4 g that is raised by one step from the bottom wall 4 a. The inlet (ie, inlet) 4h of the second clarification tank 4 is formed shallower than the other parts of the second clarification tank 4, and the bottom wall 4b on the downstream end side in the second clarification tank 4 is It is connected to the cooling tank 5 through the outlet (that is, the outlet) 4i with a constant depth.

The cooling tank 5 is elongated and has a substantially constant width in a plan view, and is configured as a tank deeper than the second clarification tank 4 as shown in FIG. Side wall portion 5b and ceiling portion 5c. A region partitioned by the third bottom wall portion 5a and the third side wall portions 5b on both sides of the cooling tank 5 is a molten glass flow path R3, and a two-dot chain line GH in FIG. Molten glass G is supplied to the cooling bath 5 so as to be in the surface position.

The upstream end side of the cooling tank 5 is an inlet (inlet part) 5e for molten glass and is connected to the outlet 4i of the second clarification tank 4, and a discharge side step 5d is provided on the downstream end side of the cooling tank 5. The forming apparatus 6 is connected to the downstream side thereof, and the molten glass G is supplied to the forming apparatus 6 from the outlet (outlet part) 5f at the downstream end of the flow path R3 formed shallow by the discharge side step part 5d. It has become so. In addition, the code | symbol 9 shown in FIG. 1 shows the stirring apparatus provided in the inside of the cooling tank 5. FIG.
In the cooling tank 5, a plurality of refractory bricks (refractory materials) are joined via joints to form a bottom wall part 5a, a side wall part 5b, and a ceiling part 5c, and as a tank as shown in FIGS. 1 and 2 as a whole. It is configured so as to have a general shape. In FIGS. 1 and 2, the thickness of the refractory brick constituting the cooling tank 5 is abbreviated and only the outline of the tank is shown.

In the clarification tank 7 of the present embodiment, the second clarification tank 4 and the cooling tank 5 are provided with inner surface covers. The inner surface cover 15 provided in the second clarification tank 4 has such a height that it can substantially surround the flow path R2 defined by the bottom wall part 4a and the

side wall parts

4b, 4b of the second clarification tank 4. It is formed in width and installed over almost the entire length of the second clarification tank 4. Further, the inner surface cover 15 provided in the cooling tank 5 is formed with a height and a width so as to substantially surround the flow path R3 defined by the bottom wall part 5a and the

side wall parts

5b and 5b of the cooling tank 5. The cooling tank 5 is installed over almost the entire length. By providing an inner surface cover on the refractory bricks on the molten glass flow path side of the second clarification tank 4 and the cooling tank 5, the second clarification tank or It can prevent that the component used as a heterogeneous base material flows out from the firebrick of a cooling tank.

Specifically, the inner surface cover 15 of the present embodiment is configured by adding a plurality of cover assemblies 16 shown in FIG. 4 and subsequent figures in the length direction of the flow paths R2 and R3, and the second clarification tank 4 and the cooling tank. 5 is applied. In addition, in this embodiment, since the inner surface cover 15 applied to the cooling tank 5 has an equivalent structure to the inner surface cover 15 applied to the second clarification tank 4, the explanation of the inner surface cover 15 described later is the second clarification. The inner surface cover 15 provided for the tank 4 will be described in detail, and the inner surface cover 15 provided for the cooling tank 5 will not be described.
In the case of the float glass plate manufacturing method, the forming apparatus 6 has a molten tin bed layer 10 (that is, a float bath containing molten tin in the float glass manufacturing apparatus) in a pool section defined by the bottom wall 6a and the peripheral wall 6b. It is provided, and the molten glass G is allowed to flow on the bed layer 10 to be spread, so that a plate-like glass can be formed. The forming apparatus is not limited to the float method, and may be a plate-shaped glass forming by a roll-out method, a downdraw method, or the like, other plate-shaped glass forming methods, a blow forming method such as a glass bottle, etc. Good.

In the manufacturing apparatus 1 of this embodiment, the second clarification tank 4 is provided with an inner surface cover 15 for protecting the inner surfaces of the bottom wall portion 4a and the side wall portions 4b and 4c as shown in FIG. The inner surface cover 15 is configured in detail as shown in FIGS. The inner surface cover 15 divides the plate and provides a gap in order to cope with the difference in thermal expansion from the furnace material during heating as described below. Further, in order to prevent the molten glass originating from the furnace material from flowing through the gap when the molten glass flows, a structure that covers the gap portion is provided as follows.
The inner surface cover 15 of the present embodiment is formed with a height and a width so as to substantially surround the flow path R2 defined by the bottom wall portion 4a and the

side wall portions

4b and 4b of the second clarification tank 4, The clarification tank 4 is installed over almost the entire length.
FIG. 4 shows a state in which a plurality of cover assemblies 16 are added to form the inner surface cover 15, a planar structure in the same state is shown in FIG. 5, and a front structure in the same state is shown in FIG. 6. FIG. 7 shows a state where is partially disassembled.

The cover assembly 16 of this embodiment includes a first plate assembly 17 and a second plate assembly that are disposed adjacent to each other in the width direction of the second clarification tank 4 (that is, the direction orthogonal to the flow direction of the flow path R2). The plate assembly 18 and the first cover plate 22 and the second cover plate 23 arranged around these plate assemblies 18 are mainly configured.
As for the 1st plate assembly 17 and the 2nd plate assembly 18, the 1st cover plate 22 and the 2nd cover plate 23, all are Mo (molybdenum), Mo alloy, W (tungsten), W It is made of an alloy or the like, or a plate made of a heat-resistant metal such as Pt, PtRh alloy, or other Pt alloy. In particular, by using a relatively inexpensive material such as Mo or W as the heat-resistant metal, a lower-cost or large-scale glass melting furnace can be realized. The glass melting furnace of the present embodiment is an unprecedented glass melting furnace of 50 tons or more, more preferably 100 tons or more, and even more preferably 500 tons or more by using an inexpensive heat-resistant metal other than Pt or Pt alloy. Can be realized. In the present invention, a glass melting furnace of at least 1000 tons can be realized. In the case of Nissan 100 tons or more, since the amount of heat brought in by the molten glass is large, it is not necessary to use a heating means in the second clarification tank. The length of the flow path of the first molten glass (that is, the length of the flow path of the molten glass in the first clarification tank 3) is preferably 4 to 15 m, and more preferably 10 to 15 m, relative to this daily production. preferable. Further, the length of the flow path of the second molten glass (that is, the length of the flow path of the molten glass in the second clarification tank 4) is preferably 2 to 15 m, and more preferably 4 to 14 m. Further, the length of the cooling tank is preferably 4 to 20 m, and more preferably 10 to 20 m.

In the clarification tank of the present invention, the extraneous material generated in the first clarification tank is discharged, and by using an inner surface cover made of a refractory metal, it is not necessary to use an expensive refractory metal. A large-scale high-temperature clarification type molten glass furnace different from the conventional scale becomes possible.
The first plate assembly 17 covers about half the width of the bottom wall portion 4a of the second clarification tank 4 (that is, about half the width direction of the bottom wall portion 4a orthogonal to the flow direction of the flow path R). The first bottom wall plate 20 having a rectangular shape and elongated in the flow direction of the flow path R2, and the first side wall plate 21 erected along the long side on one side in the width direction are mainly used. It is configured as.
The second plate assembly 18 has a width that can cover about half the width of the bottom wall portion 4a of the second clarification tank 4, and is a rectangular second bottom wall that is elongated in the flow direction of the flow path R2. The plate 25 and the second side wall plate 26 erected along the long side on one side in the width direction of the bottom wall plate 25 are mainly configured. In addition, when the width | variety of a clarification tank is wide, you may use an additional flat bottom wall plate. Also in this case, a plate that covers the gap is provided in the gap between the bottom wall plates.

In addition, a first cover plate 22 is provided so as to cover the butting region of the

first plate assemblies

17 and 17 and the butting region of the

second plate assemblies

18 and 18 arranged along the flow path R2. It has been. The first cover plate 22 includes an L-shaped third cover plate 22 A covering the end of the first bottom wall plate 20 and the end of the first side wall plate 21, and the second bottom wall plate 25. An L-shaped third cover plate 22B that covers the end portion and the end portion of the second side wall plate 26, and a fourth cover plate 24 that covers the end portion of the third cover plate 22A.

A rod-shaped joint member 28 is attached to a portion where the first side wall plate 21 is erected on the long side of the upper surface of the first bottom wall plate 20, and the bottom wall plate 20 and the side wall plate 21 are tapped. It is fixed with a screw through a joint portion 28 that has been opened. The material of the joint member 28 and the screw can be exemplified by Mo. The joint member 28 is formed slightly shorter than the overall length of the long side of the first bottom wall plate 20, and the joint member 28 does not extend outside the both ends of the joint member 28 in the first bottom wall plate 20. Corner portions 29 are formed. The joint member 28 may be provided with a step by bending or cutting as long as it has a structure that can cover the gap between the plates.

Both the first side wall plate 21 and the second side wall plate 26 are formed at the same height. These

side wall plates

21 and 26 are formed so that the upper ends thereof are lower than the liquid surface position GH of the molten glass flowing through the flow path R2. In other words, when the molten glass G flows along the flow path R2, both the first side wall plate 21 and the second side wall plate 26 are formed so as to be covered with the molten glass G as a whole. ing. This is to prevent this when the

plates

21 and 26 are made of Mo, for example, and there is a risk of burning if the Mo is in contact with air at 500 to 600 ° C.
Furthermore, on the end side of the first side wall plate 21 located on the downstream side along the flow path R2, and on the end side of the second side wall plate 26 located on the downstream side along the flow path R2,

Ear portions

21a and 26a projecting outward from the flow path R2 are formed at right angles to the

plates

21 and 26, respectively.

The third cover plate 22A is composed of a bottom plate 22a and a side plate 22b formed by bending one plate material, and is formed in an L shape. The third cover plate 22A has a corner portion 29 formed on the end side of the joint member 28 along a boundary portion between the bottom plate 22a and the side plate 22b, and a rivet or the like along the end portion of the first side wall plate 21. The fixing tool 30 is attached. The number and size of rivets can be appropriately determined depending on the plate thickness.

The fixture 30 is made of a material equivalent to the refractory metal material constituting the

plate assemblies

17 and 18. The attachment position by the fixing tool 30 may be an arbitrary position. In FIG. 5, only one place is attached at a position where the side plate 22 b faces the first side wall plate 21. About the attachment position of the fixing tool 30, the required number fixing tool 30 can be penetrated and attached to the arbitrary positions of the bottom plate 22a and the side plate 22b according to the assembly strength required for each

plate assembly

17 and 18.
The third cover plate 22A has about half of the width direction of the bottom plate 22a and the side plate 22b (that is, about half of the width direction of each plate along the flow direction of the flow path R2) as the edge portion of the first bottom wall plate 20. The first side wall plate 21 is covered with the edge portion, and the other half width is projected from the edge portion of the first bottom wall plate 20 and the edge portion of the first side wall plate 21 so as to protrude from the first side wall plate 21. It is attached to the end side of the plate 21.
In the third cover plate 22A, the length of the bottom plate 22a along the width direction of the flow path R2 is formed slightly longer than the width of the first bottom wall plate 20 along the same direction, and extends in the depth direction of the flow path R. The height of the side plate 22b along is made equal to the height of the first side wall plate 21 along the same depth direction.

The third cover plate 22B includes a bottom plate 22c and a side plate 22d, and is formed in an L shape. The third cover plate 22B is installed along the boundary portion between the bottom plate 22c and the side plate 22d at the abutting portion between the second bottom wall plate 25 and the second side wall plate 26.
More specifically, the third cover plate 22B covers about half of the width direction on the edge portion of the second bottom wall plate 25 and the edge portion of the second side wall plate 26, and the remaining half width. Is protruded from the end edge portion of the second bottom wall plate 25 and the end edge portion of the second side wall plate 26, and is attached to the second side wall plate 26 by a fixture 30 such as a rivet.
The length of the bottom plate 22c along the width direction of the flow path R2 is formed slightly shorter than the width of the second bottom wall plate 25 along the same direction, and the height of the side plate 22d along the depth direction of the flow path R2 is It is made equal to the height of the second side wall plate 26 along the same depth direction.

The second cover plate 23 is formed in an elongated rectangular shape having the same width as the

third cover plates

22A and 22B, and covers about half of the width direction on the long side of the first bottom wall plate 20 and the remaining half. The degree is projected from the long side of the first bottom wall plate 20 and is attached to the first bottom wall plate 20 by a fixture 31 such as a rivet. The total length of the long side of the second cover plate 23 is slightly shorter than the total length of the long side of the first bottom wall plate 20, and one end 23a side of the second cover plate 23 is connected to the bottom plate 22a. When extending along the side edge, the other end 23 a is disposed slightly inside the end of the first bottom wall plate 20. Therefore, the end 20a of the first bottom wall plate 20 that is not covered with the second cover plate 23 is exposed outside the end 23a of the second cover plate 23.

The fourth cover plate 24 is made of an L-shaped plate material in a plan view including a square plate-like main body portion 24a and projecting

portions

24b and 24c formed to extend on two adjacent sides thereof. The fourth cover plate 24 is made of a heat-resistant metal material equivalent to the

cover plates

22A, 22B, and 23. The fourth cover plate 24 is a corner portion of the rectangular first bottom wall plate 20 and is fixed with a rivet or the like so as to cover the abutting portion between the third cover plate 22A and the second cover plate 23. It is attached by a tool 32. The mounting direction of the fourth cover plate 24 is such that the protrusion 24b faces the width direction of the flow path R2 and away from the end of the third cover plate 22A, and the protrusion 24c is on the downstream side in the flow direction of the flow path R2. Is directed away from the second cover plate 23.
As shown in FIG. 5, the fourth cover plate 24, when the four

plate assemblies

17, 17, 18, 18 are arranged to face each other, the corner portions of the

bottom wall plates

20, 20 and the

bottom wall plates

25, 25 are arranged. It arrange | positions so that the butt | matching area | region with a corner part can be covered with a certain amount of width.

The first plate assembly 17 and the first plate assembly 18 described above are disposed so as to be adjacent to the left and right in the width direction of the flow path R2. As shown in FIG. 5, the first plate assembly 17 and the first plate assembly 18 are arranged such that the long side of the first bottom wall plate 20 and the long side of the second bottom wall plate 25 are adjacent to each other. It is installed on the bottom wall 4a of the flow path R2 with a gap D1 therebetween.
Most of the gap D1 between the first plate assembly 17 and the first plate assembly 18 is covered with the second cover plate 23 in plan view. Further, the projecting portion 24b of the fourth cover plate 24 attached to the first plate assembly 17 is placed on the end portion of the bottom plate 22c of the third cover plate 22B adjacent thereto and the end portion of the bottom plate 22b. Is covered in plan view.

The gap D1 is for absorbing the expansion when the first bottom wall plate 20 and the second bottom wall plate 25 are thermally expanded in the width direction of the flow path R2 according to the temperature of the molten glass G flowing through the flow path R2. It is provided as.
Although the cover assembly 16 can be configured by arranging the first plate assembly 17 and the second plate assembly 18 as described above, all the edge sides of the cover assembly 16 located on the downstream side of the flow path R2 are included. Can be covered with the first cover plate 22 in a plan view so that there is no gap, in other words, with the

third cover plates

22A and 22B and the fourth cover plate 24.

Next, as shown in FIG. 4 or FIG. 5, a plurality of cover assemblies 16 are arranged and connected in the same direction along the flow direction of the flow path R 2 to constitute the inner surface cover 15.
More specifically, the

third cover plates

22A and 22B and the fourth cover plate 24 are disposed at the downstream edge portion of any one cover assembly 16 along the flow path R2. The other cover assembly 16 to be installed on the downstream side of the assembly 16 is also arranged in the same direction, and the upstream edge portion of the cover assembly 16 to be arranged on the downstream side is to be arranged on the upstream side. A plurality of cover assemblies 16 are sequentially arranged in the flow direction of the flow path R 2 by being fitted so as to be fitted into the downstream edge portion of the solid body 16.

The

third cover plates

22A and 22B and the fourth cover plate 24 exist at the downstream edge of the upstream cover assembly 16, but the

third cover plate

22A or 22B and the flow path are provided. Since there are gaps corresponding to one plate between the bottom wall portion 4a of R2 and between the fourth cover plate 24 and the side wall portion 4b, the downstream side is utilized by utilizing these gaps. The end edge part of the upstream side of the cover assembly 16 can be fitted, and both can be faced | matched and arrange | positioned. When the cover assemblies 16 are engaged, a slight gap D2 is formed between the upstream cover assembly 16 and the downstream cover assembly 16 as shown in FIG. That is, a gap D 2 is formed between the first bottom wall plate 20 of the upstream cover assembly 16 and the first bottom wall plate 20 of the downstream cover assembly 16, and the upstream cover assembly 16. A gap D 2 is formed between the second bottom wall plate 25 and the second bottom wall plate 25 of the downstream cover assembly 16.
These gaps D2 are provided for absorbing thermal expansion when the first bottom wall plate 20 and the second bottom wall plate 25 are thermally expanded by the molten glass G flowing through the flow path R.

Next, the positional relationship between the inner surface cover 15 and the side wall portion 4b constituting the flow path R2 when the inner surface cover 15 is configured by joining a plurality of cover assemblies 16 will be described.
When the inner surface cover 15 is configured, the

bottom wall plates

20 and 25 of the cover assembly 16 are installed on the bottom wall portion 4a so as to cover the bottom wall portion 4a of the flow path R2, and the side wall plate 21 of the cover assembly 16 is provided. , 26 are installed along the side wall 4b so as to cover the side wall 4b of the flow path R2. About the ear |

edge parts

21a and 26a which protrude outside the cover assembly 16, it inserts in the joint part 4B which is a joining boundary of the refractory brick 4e which comprises the flow path R2.

With this structure, the first sidewall plate 21 and the second sidewall plate 26 can be stably supported by the sidewall portion 4b. Note that the slits 4s are provided on the flow path R2 side of the refractory brick 4e instead of the joints 4B of the refractory brick 4e as insertion positions of the

ears

21a and 26a, and the

ears

21a and 26a are inserted and supported in the slit 4s. A structure may be adopted.
In order to support the

side wall plates

21 and 26 of the cover assembly 16, for example, as shown in FIG. 5, a bolt-shaped fixing tool (supporting tool made of heat-resistant metal such as Mo or W so as to penetrate the refractory brick 4 e. ) 35 may be installed, and the fixing tool 35 may be passed through and fixed to the necessary portions of the

side wall plates

21 and 26 to thereby separately support the

side wall plates

21 and 26 of the cover assembly 16.
The glass product manufactured using the glass manufacturing apparatus 1 of the present embodiment is a molded product such as a glass plate manufactured by a float method, a rollout method, a downdraw method, a glass bottle manufactured by a blow method, or the like. As long as the composition is not limited. Therefore, any of soda lime glass, mixed alkali glass, borosilicate glass, or non-alkali glass may be used. Moreover, the use of the manufactured glass product is not limited to architectural use or vehicle use, and examples include flat panel display use and other various uses.

In the case of soda lime glass used for a glass plate for construction or for vehicles, it is expressed in terms of mass percentage on the basis of oxide, SiO ₂ : 65 to 75%, Al ₂ O ₃ : 0 to 3%, CaO: 5 -15%, MgO: 0-15%, Na ₂ O: 10-20%, K ₂ O: 0-3%, Li ₂ O: 0-5%, Fe ₂ O ₃ : 0-3%, TiO ₂ _{: 0 ~ 5%, CeO 2} : 0 ~ 3%, BaO: 0 ~ 5%, SrO: 0 ~ 5%, B 2 O 3: 0 ~ 5%, ZnO: 0 ~ 5%, ZrO 2: 0 ~ It is preferable to have a composition of 5%, SnO ₂ : 0 to 3%, SO ₃ : 0 to 0.5%.

In the case of an alkali-free glass used for a substrate for a liquid crystal display or an organic EL display, SiO ₂ : 39 to 75%, Al ₂ O ₃ : 3 to 27%, B ₂ O ₃ : 0 to 20%, MgO: 0 to 13%, CaO: 0 to 17%, SrO: 0 to 20%, BaO: 0 to 30% are preferable.

In the case of a mixed alkali glass used for a substrate for plasma display, it is expressed in terms of mass percentage on the basis of oxide, and SiO ₂ : 50 to 75%, Al ₂ O ₃ : 0 to 15%, MgO + CaO + SrO + BaO + ZnO: 6 to 24 %, Na ₂ O + K ₂ O: preferably 6 to 24%.

For other applications, in the case of borosilicate glass used for heat-resistant containers or physics and chemistry instruments, etc., it is expressed in terms of mass percentage based on oxide, SiO ₂ : 60 to 85%, Al ₂ O ₃ : 0 to 5% B ₂ O ₃ : 5 to 20%, Na ₂ O + K ₂ O: 2 to 10% are preferable.

In order to install the inner surface cover 15 having the above-described configuration in the flow path R2 of the second clarification tank 4, as an example, as shown in FIG. 7 in advance, the first bottom wall plate 20, the first side wall plate 21, and the third The cover plate 22A and the fourth cover plate 24 are riveted and assembled as the first plate assembly 17 in the state shown in FIG. Further, the second bottom wall plate 25, the second side wall plate 26 and the third cover plate 22B are riveted and assembled as the second plate assembly 18 in the state shown in FIG.
A plurality of the first plate assembly 17 and the second plate assembly 18 are prepared and aligned in the direction shown in FIG. 7, and these are sequentially shown in the flow path R2 of the second clarification tank 4 as shown in FIGS. By laying down and overlapping in this manner, the flow path R2 can be sequentially covered with the cover assembly 16.
Moreover, when constructing the side wall part 4b by joining a plurality of refractory bricks 4e for constituting the side wall part 4b of the second clarification tank 4 via the joint part 4B, the ear part 21a of each cover assembly 16, The inner surface cover 15 can be constructed simultaneously with the construction of the second clarification tank 4 by constructing the second clarification tank 4 while inserting 26a into the joint portion 4B.

Similarly, in the cooling tank 5, a plurality of first plate assemblies 17 and second plate assemblies 18 are prepared and aligned in the direction shown in FIG. 7, and these are sequentially arranged in the flow path R 3 of the cooling tank 5. As shown in FIG. 5, the flow path R 3 can be covered with the inner surface cover 15 by spreading and overlapping.
By the way, in the description so far, the configuration in which the

cover assemblies

16 and 16 are sequentially laid down with the cover plate 22 facing the downstream side of the flow paths R2 and R3 has been described, but the upstream side of the flow paths R2 and R3. Alternatively, the

cover assemblies

16 and 16 may be sequentially spread and arranged with the cover plate 22 facing toward each other, and the arrangement direction of the cover assembly 16 is not limited in the present invention.

Next, a method for manufacturing a glass product using the glass product manufacturing apparatus 1 including the second clarification tank 4 and the cooling tank 5 including the inner surface cover 15 described above will be described below.
In the manufacturing apparatus 1 of this embodiment, a glass raw material is melt | dissolved in the melting tank 2, the molten glass G is produced | generated, and methods, such as circulating this molten glass G in the melting tank 2, are employ | adopted, and a certain amount of bubble removal is carried out. After that, it is moved to the first clarification tank 3. A step of melting the glass raw material in the melting tank 2 to form a molten glass is referred to as a glass melting step S1 as shown in FIG.

In the first clarification tank 3, the temperature of the molten glass is adjusted to a high temperature in the range of about 1420 to 1510 ° C. by conducting heating with the electrode 8 and clarified. By maintaining in the high temperature range of this range, bubbles are grown and bubbles are removed by the effect of the clarifying agent contained in the components of the molten glass G. Moreover, since the viscosity of the molten glass G falls by heating to the high temperature of this range, a bubble also grows easily and it becomes easy to float and escape.
When the plurality of electrodes 8 are energized and heated, as an example, when 12 electrodes 8 are arranged in a line of 6 × 2 in the first clarification tank 3 as shown in FIG. For AC energization, the R-phase, T-phase, and S-phase may be selected as a pair indicated by an arrow between the diagonally adjacent electrodes 8 as indicated by the arrow, and the three phases may be sequentially energized. In addition, other examples of energization heating for these electrodes 8 will be described in detail in later embodiments.

When the plurality of electrodes 8 are energized, the molten glass G existing around the electrode 8 and heated is heated to a higher temperature than the surrounding molten glass G, and the molten glass heated to a higher temperature is the electrode 8. Therefore, a convection of the molten glass G is generated around the electrode 8, so that a partial convection of the molten glass G is generated inside the first fining tank 3. Thereby, a partial circulation flow of the molten glass G is generated inside the first clarification tank 3. Of these circulating flows, the molten glass G located on the outlet 3h side of the first clarification tank 3 and close to the liquid level GH is sent to the second clarification tank 4 side. In order to efficiently remove bubbles as described later without heating in the second clarification tank 4, the temperature of the molten glass G is the highest on the outlet 3h side of the first clarification tank 3 (that is, the highest). It is preferable that the plurality of electrodes 8 are sequentially heated so that the temperature reaches the final temperature.
Here, for example, when the temperature of the molten glass G in the first clarification tank 3 is set in the range of 1420 to 1510 ° C., each temperature is set so that the temperature of the molten glass G reaches the maximum temperature of 1510 ° C. on the outlet port 3h side. It is preferable to control energization of the electrode 8.

In the present embodiment, the upper limit temperature (maximum temperature reached) on the outlet 3h side of the molten glass G in the first clarification tank 3 is set to 1510 ° C. in the soda lime glass by using SO ₃ as a clarifier. This is an example in the case of molten glass G containing about 2% by mass. When SO ₃ is contained in an amount of less than 0.2% by mass, the highest temperature reached on the outlet 3h side is set higher, and SO ₃ is When it contains more than 0.2 mass%, what is necessary is just to set the highest ultimate temperature by the side of the outlet 3h lower. As described above, the maximum temperature at the outlet 3h side in the first clarification tank 3 can be set as appropriate according to the composition of the molten glass G to be applied. It is preferable to set the temperature. The reason for controlling the temperature in this way is that the molten glass G is not actively heated in the next second clarification tank 4 and the uniflow state from the upstream side to the downstream side in the second clarification tank 4 as described later. This is because the bubbles are removed as smoothly as possible when the bubbles are generated.

After defoaming to some extent in the first clarification tank 3, the molten glass is guided to the second clarification tank 4 to further proceed with clarification treatment to defoam.
When the molten glass moves from the first clarification tank 3 to the second clarification tank 4, the first clarification tank 3 has a certain depth and is heated by energization with the plurality of electrodes 8. Although the convection is partially generated, the second clarification tank 4 is shallow and basically does not heat the molten glass G. Therefore, the second clarification tank 4 basically does not generate a return flow of the molten glass. Then, a constant flow from the inlet 4h side (upstream side) to the outlet 4i side (downstream side) is generated (ie, in a uniflow state) to move the molten glass to the cooling tank 5 side.

The uniflow state will be described below. The generation of natural convection due to the temperature difference between the upstream side and the downstream side can be cited as a cause of hindering uniflow in the flow path of the second clarification tank 4. Specifically, an upward flow is generated on the upstream side of the high temperature, and a downward flow is generated on the downstream side of the low temperature, so that natural convection in the return direction is generated at the bottom. When the strength of the molten glass main flow is sufficiently large due to the strength of this natural convection, a uniflow flow that is a unidirectional flow with different flow velocities occurs along the depth direction of the molten glass. On the other hand, when the strength of natural convection is not sufficiently greater than the strength of the molten glass mainstream, a flow in the direction opposite to the mainstream is generated at the bottom.
In general, the ratio between the strength of natural convection and the strength of forced convection is expressed as the ratio Gr / Re ^{2 of} the square of the Grashof number Gr and the Reynolds number Re, that is, the ratio between buoyancy and inertial force. Therefore, this ratio was adopted as a uniflow parameter for generating uniflow. In designing the second clarification tank, by using this uniflow parameter, the flow rate of the molten glass, the temperature change of the molten glass at the inlet and outlet of the molten glass channel, the depth of the molten glass are set, Uniflow state can be realized.
By making the flow in this uniflow state, the bubbles remaining in the first clarification tank 3 are efficiently removed in the second clarification tank 4 without causing a flow of molten glass returning to the first clarification tank 3. it can.
In addition, the range of the ratio Gr / Re ² of the square of the Grashof number Gr and the Reynolds number Re that causes this uniflow state is preferably 11420 or less, and more preferably 6500 or less in order to form a strong uniflow.
About this range, since the shape of the second clarification tank is simple, it is a hexahedral three-dimensional shape, and using the physical properties of general soda lime glass, the average temperature of the molten glass at the entrance of the clarification tank and By conducting a general three-dimensional thermal convection analysis using three parameters: the difference from the average temperature of the molten glass at the outlet, the average flow velocity of the molten glass, and the depth of the fining tank, the uniflow parameter is set to 370 to 40148. It was obtained by calculating 51 cases that varied in range.

Note that the kinematic viscosity of the molten glass was calculated as a function of the temperature of the molten glass. Further, in realizing the uniflow state, the method is not limited to the above method, and other methods may be used.
The temperature of the second clarification tank 4 is about 1510 ° C. on the inlet 4h side and about 1500 ° C. on the outlet side, and clarification of the molten glass can be promoted by this high temperature treatment. That is, bubbles in the molten glass G can be smoothly grown and floated, and bubbles can be removed by breaking the bubbles at the liquid surface position GH.
Since the above-mentioned inner surface cover 15 is provided in the second clarification tank 4, the function and effect of the inner surface cover 15 can be obtained. Details of the function and effect will be described later.

The molten glass that has been defoamed in the second clarification tank 4 is cooled in the cooling tank 5 to its molding temperature range so that the molten glass can be molded. More specifically, the molten glass is cooled in the cooling tank 5 from a temperature of about 1500 ° C. on the inlet side to a temperature of about 1200 ° C. on the outlet side. The cooling tank 5 is provided with a stirring device 9, and while cooling is promoted by stirring, cooling can be promoted by providing a cooling device such as a water cooling tube as necessary.
In the present embodiment, the step of cooling and adjusting to the molding temperature range so as to be clarified in the first clarification tank 3 and the second clarification tank 4 and to form molten glass, as shown in FIG. This is referred to as S2.
The molten glass cooled to about 1200 ° C. in the cooling bath 5 is spread on the molten tin bed layer 10 and further cooled in the forming apparatus 6 in the next step, for example, in the case of a float glass plate manufacturing method. It can be a sheet glass. In this embodiment, the step of forming the sheet glass using the forming device 6 is referred to as a forming step S3 as shown in FIG.
Then, a slow cooling step S4 for slowly cooling the sheet glass to a temperature close to room temperature as shown in FIG. 8 is performed, and a cutting step S5 for cutting to a target size is performed, so that the target glass product G6 as shown in FIG. Can be obtained.

In the above manufacturing process of the glass product G6, in the present embodiment, the temperature of the molten glass G is not refoamed by energization heating with the plurality of electrodes 8 in the first clarification tank 3, and is as high as possible, for example, Heating is performed at about 1510 ° C. on the outlet side of the first clarification tank 3. As an example of the temperature distribution in the first clarification tank 3, the electrode 8 can be heated so that the temperature gradually increases from the inlet side to the outlet side so as to be 1420 ° C. on the inlet side and 1510 ° C. on the outlet side. .
In the second clarification tank 4, the flow of the molten glass G in the second clarification tank 4 flows in one direction along the flow path R 2 and becomes a uniflow state, and the molten glass moved to the second clarification tank 4. Since G is a high temperature of 1500 to 1510 ° C., the bubbles can be more efficiently removed from the molten glass G that becomes high temperature in a uniflow state. As a result, the bubbles can be sent to the next cooling bath 5 efficiently. .

Moreover, in this embodiment, the 2nd clarification tank 4 and the cooling tank 5 are provided with the inner surface cover 15 made from a heat-resistant metal.
In the second clarification tank 4, the inner surface cover 15 covers the inner surface side of the bottom wall portion 4a and the side wall portion 4b constituting the flow path R2 of the molten glass G, and thus constitutes the bottom wall portion 4a and the side wall portion 4b. Direct contact between the refractory brick and the molten glass G can be reduced as much as possible, and it can be suppressed that foreign components from the refractory brick are eluted to the molten glass G side.
In the cooling tank 5, the inner surface cover 15 covers the inner surfaces of the bottom wall portion 5a and the side wall portion 5b constituting the molten glass flow path R3, so that the refractory brick G constituting the bottom wall portion 5a and the side wall portion 5b is melted. Direct contact with the glass is reduced as much as possible, and it is possible to suppress the foreign component from the refractory brick from being eluted to the molten glass G side.
Accordingly, even when the clarification of the molten glass G is continuously performed for a long period of time, the molten glass G is produced without causing elution of foreign components from the refractory bricks in the molten glass G flowing through the flow paths R2 and R3. It can be performed. Therefore, a high-quality glass product G6 can be obtained by sending a high-quality molten glass G having a uniform composition to the next process and forming it with the forming apparatus 6.
In addition, the glass product which grind | polished the molten glass after shaping | molding as needed, and grind | polished the surface can also be manufactured.

By the way, when flowing the molten glass G for the first time at the start of production of molten glass to the flow paths R2 and R3 provided with the Mo inner surface cover 15 in the second clarification tank 4 and the cooling tank 5, Since air is present, it is necessary to prevent the inner cover 15 from burning when the inner cover 15 is heated to 500 to 600 ° C. or higher.
In order to prevent combustion of the inner cover 15 at the start of production, it is preferable to form a coating layer on the entire inner cover 15 so that Mo does not come into contact with air. For example, a silica coat film can be adopted as the coating layer. Since the silica coat film may prevent the reaction between Mo and air before the molten glass G covers the entire inner surface cover 15 at the start of production of the molten glass, the molten glass G covers the entire inner surface cover 15. Cover with a film thickness sufficient to withstand time. After the molten glass G covers the entire inner surface cover 15, the silica coat film melts and disappears as time passes, and thereafter, the molten glass G covering the inner surface cover 15 isolates the inner surface cover 15 from the air.

Next, the effect of the inner surface cover 15 of this embodiment is further demonstrated.
In the inner surface cover 15 covering the inner surfaces of the flow paths R2 and R3 as described above, a gap D1 is formed between the first bottom wall plate 20 and the second bottom wall plate 25, and the flow of the flow path R2 A gap D2 is formed between the

cover assemblies

16 and 16 adjacent to each other in the front and rear direction.
The thermal expansion coefficient of the refractory brick 4e constituting the bottom wall portion 4a and the side wall portion 4b of the flow path R2 is different from that of the inner surface cover 15 made of a heat-resistant metal such as Mo. When the molten glass G flows through the flow paths R2 and R3, each plate constituting the inner surface cover 15 expands more than the refractory brick 4e having a low coefficient of thermal expansion. Here, since the gaps D1 and D2 are formed on the inner side of the inner cover 15, the thermal expansion of each plate constituting the inner cover 15 can be absorbed by the gaps D1 and D2, and the molten glass G Thus, unnecessary thermal stress can be prevented from being applied to the inner surface cover 15 in a heated state. Therefore, even if the molten glass is manufactured by continuously using the second clarification tank 4 and the cooling tank 5 provided with the inner surface cover 15, unnecessary burdens such as thermal stress do not act on the inner surface cover 15.

Moreover, the following effects can be acquired by inserting the ear |

edge parts

21a and 26a of the cover assembly 16 of this embodiment in the joint part 4B or slit 4s of the refractory brick 4e of the circumference | surroundings.
When the molten glass G flows along the flow path R2, the molten glass G flows through the flow path R2 on the inner surface side of the inner surface cover 15, and at the same time, the bottom wall portion 4a and the side wall portion 4b of the flow path R2 and the inner surface cover 15 A small amount of molten glass G also flows into the gap portion with the back side.
Here, even if a plurality of cover assemblies 16 are engaged to form the inner surface cover 15 and cover the surface of the bottom wall portion 4a and the side wall portion 4b of the flow path R2, the inner surface of the flow path R2 The bottom surface and the side surface of the inner cover 15 are not completely in close contact with each other. Further, the upper ends of the

side wall plates

21 and 26 of the inner surface cover 15 are at a position lower than the liquid level GH of the molten glass, and the inner surface cover 15 has gaps D1 and D2, so the back side of the inner surface cover 15 is provided. In addition, some molten glass G wraps around.

The molten glass G flowing between the bottom wall portion 4a and the side wall portion 4b of the flow path R2 and the inner surface cover 15 directly contacts the bottom wall portion 4a and the side wall portion 4b, so that the bottom wall portion 4a and the side wall portion 4b are configured. There is a risk of eroding the refractory bricks depending on the operation for a long period of time, or part of the components constituting the refractory bricks eluting to the molten glass side to contaminate the molten glass. However, the amount of the molten glass G flowing between the bottom wall portion 4a and the side wall portion 4b and the back surface side of the inner surface cover 15 is extremely small with respect to the main flow of the molten glass flowing inside the flow path R2, Since the molten glass that has flowed into the back surface side of the inner surface cover 15 cannot easily return to the flow path R2 side, the molten glass G that flows through the flow path R2 inside the inner surface cover 15 is slightly present behind the inner surface cover 15. The possibility of the dirty molten glass G to be affected is low.

In some cases, the molten glass G flowing between the bottom wall portion 4a and the side wall portion 4b and the back surface side of the inner surface cover 15 tends to move along the flow direction of the flow path R2. However, since the

ear portions

21a and 26a are intermittently present at a plurality of locations in the length direction of the inner surface cover 15, the molten glass G travels along the back surface side of the inner surface cover 15 and moves downstream in the flow path R2. The

ears

21a and 26a block the flow to be attempted. As a result, the molten glass G on the back surface side of the inner surface cover 15 that is likely to get dirty by touching the side wall portion 4b is not sent to the downstream side of the flow path R2.
For this reason, there is no fear of sending the dirty molten glass to the molding apparatus 6 provided on the downstream side of the second clarification tank 4 and the cooling tank 5, and the high quality of the uniform composition free of impurities and with few bubbles There is an effect that the molten glass can be sent to the molding device 6 and molded.

In addition, the area | region which installs the inner surface cover 15 demonstrated so far is installed about the area | region where a molten glass temperature becomes 1200 degreeC or more in view of the temperature below about 1200 degreeC considered that the elution of a foreign material does not occur from a refractory brick. It is preferable. By covering this area with the inner surface cover 15, it is possible to prevent elution of foreign components from the refractory brick.

FIG. 9 shows an example of an apparatus for manufacturing a glass product provided with a clarification tank according to the second embodiment of the present invention, and FIG. 10 shows a state in which a main part of the apparatus for manufacturing a glass product provided with the clarification tank is viewed from a plane. An example is shown.
The glass product manufacturing apparatus 55 of this embodiment includes a glass melting furnace 56 having a melting tank 2 and a clarification tank 57. The clarification tank 57 in the glass melting furnace 56 has substantially the same structure as the clarification tank 7 of the first embodiment. In the clarification tank 57 of the present embodiment, the arrangement of the electrodes 8 arranged in the first clarification tank 3 and the energization state of these electrodes 8 are different from those of the first embodiment, and the first clarification tank 57 3 is different in that a second drain-out portion 3i is provided on the bottom wall portion 3a, and a first convex portion 4j is formed on the outlet 4i side of the second clarification tank 4.

In the first clarification tank 3 of the present embodiment, in addition to the drain-out portion 3e provided at the bottom of the outlet port 3h side (downstream end side) of the flow path R1, the inlet port 3f side (upstream side) than that. A drain-out portion 3i is formed in the bottom. As with the previous drain-out portion 3e, a plurality (four in the form shown in FIG. 10) are aligned in the width direction of the first clarification tank 3 with respect to the drain-out portion 3i.
In the structure of the present embodiment, four electrodes 8 arranged in the first clarification tank 3 are arranged in a total of 12 electrodes in four rows. Among these, a total of nine electrodes 8 are arranged between the introduction port 3f and the drain-out portion 3i, and a total of nine electrodes 8 are arranged, and the remaining three electrodes 8 are arranged between the drain-out portion 3i and the drain-out portion 3e. Is arranged. The number of electrodes varies depending on the amount of molten glass to be melted, the width of the fining tank, and the like, and can be set as appropriate.

In the second embodiment, four electrodes in each row aligned along the length direction of the flow path R1 out of twelve electrodes 8 arranged in three rows of four in plan view as shown in FIG. 8 is an R-phase electrode, the second electrode is a T-phase electrode, the third electrode 8 is an S-phase electrode, and the fourth electrode 8 is an R-phase electrode. Yes.
Further, in the present embodiment, as shown in FIG. 10, four electrodes in each row aligned along the length direction of the flow path R1 out of the twelve electrodes 8 arranged in three rows by four in plan view as shown in FIG. 8 is an R-phase electrode, the second electrode is an S-phase electrode, the third electrode 8 is a T-phase electrode, and the fourth electrode 8 is an R-phase electrode in order from the inlet 3f side. May be.

In the arrangement of the three-phase electrodes shown in FIG. 10 at the top and bottom, the three-phase electrodes are arranged in a combination in which the phase difference between adjacent electrodes is 120 degrees, specifically the left side (that is, upstream of the first clarification tank 3). The three-phase electrode arrangement arranged in the order of R phase, S / T phase, S / T phase, and R phase is arranged in order from the left side, R phase, S phase, T phase, and R phase. The current density applied to the surface of the molten glass G can be made lower and uniform than the three-phase electrode arrangement.
Further, in order from the left side shown in FIG. 10, a three-phase electrode arranged in the order of R phase, S / T phase, S / T phase, and R phase, which is a combination arrangement in which the phase difference between adjacent electrodes is 120 degrees. If it is the arrangement, the current density applied to the surface of the molten glass G in the electrode 8 is set to a lower value than the three-phase electrode arrangement arranged in order from the left side, the R phase, the S phase, the T phase, and the R phase. it can. About an electric current density, it can determine suitably according to the quantity of the molten glass to manufacture, and the molten glass temperature in the melting tank to request | require.

From the left side of the three-phase diagram shown in FIG. 10, as a result of examining how the R-phase, S-phase, and T-phase are arranged in the arrangement of the electrode 8 shown in FIG. It was found that the current density in the electrode surface region in the second row can be reduced in the case of the three-phase electrode arrangement in which the interelectrode phase is arranged in the order of the RS phase, TS phase, and TR phase. The ability to reduce the current density means that the consumption of the electrode is reduced when assuming a glass melting furnace that operates continuously for a long period of time, such as in the production of molten glass.
In addition, the current density was calculated for an electrode array of 6 × 2 rows having the configuration shown in FIG. As a result, the average current density when the four pairs of electrodes on the upstream side of the first clarification tank 3 are energized as indicated by the X-shaped arrow is 0.69 A / cm ² between the electrodes indicated by the arrow S ₁ , and the arrow S _2. 0.62A / cm ² in between the electrodes indicated by, 0.66A / cm ² in between the electrodes indicated by the arrow _{S 3,} 0.64A / cm ² in between the electrodes indicated by the arrow _{S 4,} in between the electrodes indicated by the arrow _{S 5} 0.92A / cm ^2, in between the electrodes indicated by the arrow _{S 6} resulted in 0.67A / cm ^2.
From this result, it can be seen that the electrode arrangement of FIG. 2 has an electrode with a high current density of 0.92 A / cm ² , which is disadvantageous in terms of current density compared to the structure of the electrode arrangement of FIG.

In the above structure, the drain-out portions 3e and 3i are provided before and after the electrode 8 on the outlet 3h side of the first clarification tank 3, but when the drain-out portions 3e and 3i are provided before and after the electrode 8, The upward flow of the molten glass generated around these electrodes 8 can be suppressed. Thereby, even if the molten glass G having a low temperature stays on the bottom side of the outlet 3h of the first clarification tank 3, the retained molten glass G may contain foreign components from the furnace material. The dirty molten glass G can be discharged from the drain-out portions 3e and 3i without being sent out to the second clarification tank 4 side.

Next, in the clarification tank 57 of the second embodiment, the second clarification tank 4 is in contact with the side wall 4b on both ends in the width direction on the outlet 4i side (downstream end side) of the bottom wall 4a. One convex portion 4j is formed.
As shown in FIG. 11A, the first convex portion 4j has a rectangular parallelepiped shape (block shape) along the flow path R2 on the downstream end side of the bottom wall portion 4a. The width is about a fraction of the width of R2 and is about a fraction of the depth of the molten glass G flowing through the flow path R2 (that is, the liquid level height GH of the molten glass). Yes. FIG. 11A is a schematic longitudinal sectional perspective view in which the flow path R2 of the second clarification tank 4 and the flow path R3 of the cooling tank 5 are sectioned along the center in the width direction of these flow paths. A region about half the width of R2 and R3 is shown. In FIGS. 11B to 11F below, the cross-sectional positions are the same.

The first convex portion 4j may be the first convex portion 4k having a rectangular parallelepiped shape shown in FIG. 11 (B) formed slightly wider than the shape shown in FIG. 11 (A). As shown in FIG. 11C, the first protrusion 4l having a wider rectangular parallelepiped shape may be used, or the first protrusion 4m having a substantially square block shape may be used as shown in FIG. Moreover, the 1st convex part 4n which occupies the full width along the flow path R2 in the outlet port side (downstream end side) of the bottom wall part 4a as shown in FIG.11 (E) may be sufficient. Further, as shown in FIG. 11 (F), the first convex portions 4p are formed on the both ends in the width direction on the outlet port 4i side of the rectangular parallelepiped bottom wall portion 4a, and the first convex portions 4p are formed. Alternatively, the second convex portion 4r having a rectangular parallelepiped shape may be provided on the introduction port 4h side (upstream side) so as to be in contact with the side wall portion 4b.

As for the first convex portions 4j to 4p and the second convex portion 4r, when bubbles are contained in the molten glass G moving through the flow path R2 of the second clarification tank 4, the bubbles grow. Thus, it is provided to prevent the bubbles from moving to the bottom side of the molten glass G so as to easily float.
That is, the molten glass G heated to the highest temperature in the first clarification tank 3 on the outlet 3h side of the first clarification tank 3 flows into the second clarification tank 4 while maintaining the temperature. In the second clarification tank 4, the molten glass G flows in the uniflow state toward the discharge port 4i side as shown by an arrow F in FIG. 11A without being heated. Here, since the molten glass G flowing on the region side in contact with the side wall portion 4b of the second clarification tank 4, that is, on both ends in the width direction of the flow channel R2, is deprived of more heat by the side wall portion 4b. The temperature drops faster than the molten glass G flowing through the central portion of R2. That is, as a result of the molten glass G at both ends in the width direction of the flow path R2 becoming lower in temperature, the low temperature molten glass G sinks from the upper side to the lower side of the area at both ends in the width direction of the flow path R2. A flow is generated, and the bubbles that are about to fall to the liquid surface side move toward the bottom side of the molten glass G by the downward flow.
When sinking as described above occurs in the molten glass G flowing at both ends in the width direction of the flow path R2, the bubbles float on the liquid surface, and the bubbles that should be lost by breaking are not lost, but the cooling tank 5 side There is a risk of moving to. In order to suppress such a phenomenon, the first convex portions 4j to 4p and the second convex portion 4r are provided.

When the first convex portions 4j to 4p and the second convex portion 4r are provided on the downstream end side of the bottom wall portion 4a, the molten glass G in a uniflow state hits these convex portions and follows the peripheral surface of the convex portion. An upward flow is formed in the flow in the direction of detouring around and the flow of the partially molten glass G. As a result, even if the molten glass G that is about to sink sinks bubbles to the bottom side, the bubbles can be moved to the liquid surface side along the upward flow, so that the bubbles are close to the liquid surface of the cooling bath 5. A flow to be moved can be generated, and thereby bubbles can be put out on the liquid surface and broken, so that bubbles contained in the molten glass G of the cooling bath 5 can be reduced. In addition, since the flow velocity in the direction detouring the convex portion decreases, the bubble rises accordingly, the bubble easily rises and comes out to the liquid surface, so that the bubble can be removed.
Moreover, the 2nd convex part 4r shown to FIG. 11 (F) has an effect | action which bypasses the flow of the molten glass G in the middle of the flow path R2, and suppresses sinking of a bubble. Therefore, coupled with the effect of providing the first convex portion 4p, it is possible to promote the rising of the bubbles and prevent the bubbles from sinking. Therefore, a structure in which the second protrusion 4r is provided separately from the first protrusions 4j to 4p at an arbitrary position in the flow path R2 may be employed.

From the above, with respect to the first convex portions 4j to 4r, in the second clarification tank 4, it is possible to effectively prevent the sinking of bubbles at both ends in the width direction of the flow path R2, thereby bypassing the flow. In order to reduce the flow velocity, it is preferable that the bottom wall portion 4a is formed on the downstream end side, at least on both ends in the width direction of the bottom wall portion 4a so as to be in contact with the side wall portion 4b. Accordingly, the convex portion may be formed to the full width of the bottom wall portion 4a as in the first convex portion 4n shown in FIG. 11E, and although not shown in FIG. 11A to FIG. 11 (D) may be formed intermittently in the width direction of the bottom wall portion 4a on the downstream end side of the second clarification tank 4.

FIG. 12 shows an example of the inner surface cover applied to the clarification tank according to the present invention in which the upper end of the Mo side wall plate 21 in the cover assembly is arranged so as to protrude upward from the liquid surface position GH of the molten glass G. It is sectional drawing which shows a structure.
When the Mo side wall plate 21 is arranged so as to protrude upward from the liquid surface position GH of the molten glass G as in this embodiment, the outer side of the inverted U-shaped cross section is arranged so that the side wall plate 21 does not come into contact with air. The upper end portion of the side wall plate 21 is covered by the first cover piece 51 and the inner second cover piece 52.
The outer first cover piece 51 is made of a Pt alloy such as Pt and PtRh, and a heat resistant metal material such as iridium, and the inner second cover piece 52 is made of a heat resistant ceramic such as alumina (Al ₂ O ₃ ) and zirconia. .

The outer first cover piece 51 is made of a heat-resistant metal that is not susceptible to erosion of the molten glass G and that does not cause any problems even when exposed to air, and the second cover piece 52 made of heat-resistant ceramic is constructed of the clarification tank 4. When the silica coating layer is formed on the cover assembly 16 when the molten glass G is flowed for the first time, Pt is damaged when the silica coating layer comes into contact with Pt. This is provided to prevent this damage. From this point of view, the position of the lower edge portion 51a of the outer first cover piece 51 is formed so as to be positioned above the lower end portion 52a of the inner second cover piece 52, and the first cover It is desirable that the lower end portion 51a of the piece 51 is separated from the surface of the side wall plate 21 by about several tens of millimeters.

By adopting the structure shown in FIG. 12, the upper end positions of the Mo

side wall plates

21 and 26 can be disposed above the liquid surface position GH of the molten glass G. According to this structure, the side wall portion 4b constituting the flow path R2 can be covered with the inner surface cover 15 in a wider range. Thereby, since the 1st side wall plate 21 can be arrange | positioned above the liquid level position GH of the molten glass G, the structure where the molten glass G does not touch the refractory brick 4f directly near the liquid level GH of the molten glass G is implement | achieved. it can. Moreover, even if the glass manufacturing apparatus 1 is operated so that the liquid level position GH of the molten glass G fluctuates up and down and the clarification tank 4 is used, a structure in which the

side wall plates

21 and 26 are hardly damaged can be provided. That is, even if the liquid level position GH of the molten glass G changes about the height of the first cover piece 51, the

side wall plates

21 and 26 do not come into contact with air. Even if the liquid level position GH fluctuates, there is no problem.
Further, since elution of impurities from the

refractory bricks

4e and 4f side to the molten glass G near the liquid level position GH can be prevented, impurities are not mixed into the molten glass G near the liquid level position GH.

FIG. 13 shows an example in which

ears

20c and 25c are provided on the end side of the first bottom wall plate 20 and the second bottom wall plate 25 in the cover assembly 16 applied to the present invention. Other structures are the same as those of the first embodiment.
As in the structure of this embodiment, the ear portion 20c is provided downward on the end portion side of the first bottom wall plate 20, and the ear portion 25c is provided downward on the end portion side of the second bottom wall plate 25. Also, the first bottom wall plate 20 and the second bottom wall plate 25 are placed on the bottom wall 4a of the clarification tank 4 by inserting them into the joints or slits 4s of the refractory brick 4c constituting the bottom wall 4a. is set up.

In the structure of this example, since the ear | edge

parts

20c and 25c are formed in the edge part side of the 1st bottom wall plate 20 and the 2nd bottom wall plate 25, the 1st bottom wall plate 20 and the 2nd bottom wall plate 20 The

ears

20c and 25c block the flow of the molten glass G that is about to flow along the flow path R2 through the gap area between the bottom wall plate 25 and the bottom wall 4a of the flow path R2, and are transmitted through the gap area. Thus, the flow of the molten glass G that tends to flow downstream of the flow path R2 can be prevented.
By forming the

ear portions

20 c and 25 c on the end portions of the first bottom wall plate 20 and the second bottom wall plate 25, the dirty molten glass G can be prevented from flowing to the downstream side of the clarification tank 4.
Therefore, according to the structure of this example, as in the structure of the first embodiment, the dirty molten glass G in the gap portion between the side wall portion 4b and the cover assembly 16 is not allowed to flow downstream. It is possible to provide a structure in which the molten glass G contaminated in the gap between the portion 4a and the cover assembly 16 does not flow downstream.

FIG. 14 shows an example of a cover assembly 16A applied to the inner surface cover 15A according to the present invention. In this example, the structure of the first embodiment is different from that of the first embodiment. The first bottom wall plate 20 and the second bottom wall plate 25 that have been used are integrated into a single bottom wall plate 60. In addition, the first plate assembly 17 and the second plate assembly 18 separated in the previous first embodiment are integrated into a single plate assembly 61. Furthermore, the

third cover plates

22A and 22B separated in the previous first embodiment are integrated, and the U-shaped cover plate 62 is shared in cross section, and the fourth cover plate 24 is omitted. ing. The cover plate 62 is formed in a U shape including a bottom plate 62a and side plates 62b on both sides.

In the structure of this example, the bottom plate 62a of the cover plate 62 is put on the edge of the bottom wall plate 60 by about half the width, and the remaining half of the width is projected, and the end of the cover assembly 16A is fixed by a fixture such as a rivet (not shown). A cover plate 62 is fixed to the edge portion. Further, one side plate 62b of the cover plate 62 is put on the first side wall plate 21 by a half width, the remaining half width is projected, and the other side plate 62b is half a width on the edge side of the second side wall plate 26. The cover plate 62 is fixed to the end edge portion of the cover assembly 16A by a fixing tool such as a rivet (not shown). Further, the

side wall plates

21 and 26 are formed by bending a single heat-resistant metal plate with respect to the bottom wall plate 60.

The bottom wall portion 4a and the

side wall portions

4b and 4b of the flow path R2 can be protected from the molten glass G also by the inner surface cover 15A of this example. And the absorption effect of the thermal expansion when the

cover assemblies

16A and 16A expand in the length direction of the flow path R2 can be obtained in the same manner as the structure of the first embodiment. That is, the length of the flow path R2 using the gap between the

bottom wall plates

60, 60 adjacent to each other in the flow direction of the flow path R2, the clearance between the

side wall plates

21, 21, and the clearance between the

side wall plates

26, 26. The absorption effect of the thermal expansion when the

cover assemblies

16A and 16A are thermally expanded in the direction can be obtained.

The inner surface cover 15A in this example shares the first plate assembly 17 and the second plate assembly 18 that are adjacent to each other in the width direction of the flow path R2, and thus covers the width direction of the flow path R2. Although the absorption effect when the assembly 16A expands is not obtained, the

side wall plates

21 and 26 are not in close contact with the side wall portion 4b of the flow path R2, but are disposed with a slight gap therebetween. The structure shown in FIG. 14 can be applied to a structure that does not need to consider the thermal expansion in the width direction.

For example, when the side wall plate 26 is supported by a bolt-shaped fixture (support) 35 made of a heat-resistant metal such as Mo so as to penetrate the refractory brick 4e as shown in FIG. 6, the side wall plate 26 and the refractory brick 4e, Since it is easy to make a gap with 4f, this gap can be used for absorbing thermal expansion. In this case, it is not necessary to firmly fix the fixture 35 to the side wall plate 26, and it is preferable to engage the side wall plate 26 so that the side wall plate 26 can move somewhat in the axial direction of the fixture 35. Of course, if the ear portion 26a of the side wall plate 26 is supported by the joint portion 4B of the refractory brick 4e, there will be no problem with the structural strength of the side wall plate 26.

FIG. 15: is a block diagram which shows an example of the manufacturing apparatus of the glass product provided with the clarification tank based on 3rd Embodiment of this invention.
The glass product manufacturing apparatus 80 of this embodiment includes a glass melting furnace 90 having a melting tank 2 and a fining tank 97. The clarification tank 97 in the glass melting furnace 90 has substantially the same structure as the clarification tank 7 of the first embodiment.
In the clarification tank 97 of the present embodiment, as a heating means provided in the first clarification tank 3 with respect to the clarification tank 7 of the first embodiment, the side wall portion 3b of the first clarification tank 3 is used instead of the electrode 8. The difference is that a plurality of horizontal oxygen combustion burners 91 are arranged. In this case, a metal plate made of refractory metal that covers the refractory brick on the flow path side can be provided for the refractory brick flow path. The installation of the inner surface cover, which is this metal plate, is as described above.

In the first clarification tank 3, in order to set the temperature of the molten glass G to a temperature at which a clarification effect can be obtained, a plurality of oxygen combustion burners 91 are provided instead of the electrodes 8 to generate the combustion flame 92, The molten glass G is heated to a target temperature.
In order to cause convection of the molten glass G in the first clarification tank 3, a structure in which a plurality of electrodes 8 are provided separately from the oxyfuel burner 91 may be employed.

Also in the glass melting furnace 90 of the third embodiment, the first clarification tank 3 and the second clarification tank 4 can remove bubbles in two stages as in the clarification tank 7 of the first embodiment, and there are few bubbles. The molten glass G can be sent to the molding apparatus 6 to produce a glass product.
The present invention is not particularly limited with respect to the melting tank, but a mixed powder raw material obtained by mixing glass raw material powders at a predetermined ratio is directly blown out of a burner to form molten glass in a high-temperature gas phase atmosphere (reference) As a document, for example, molten glass may be melted in a melting tank disclosed in JP-A-2006-199549).
This is because, according to the air melting method, the glass raw material powder melts in a gas phase atmosphere, so that the amount of water in the molten glass is larger than that of electric melting or melting by a normal burner. This is because the clarification effect can be enhanced.
According to the air melting method, the amount of water in the molten glass varies depending on the difference in glass composition and the method of producing the glass raw material particles, but the wavelength of 2.75-2. It has been found that when the absorbance to 95 μm light is measured, it is at least 600 ppm or more. It has been found that this moisture content is clearly higher than 400-600 ppm in the case of electric melting and 300 ppm in the case of melting with a normal burner. The upper limit of the amount of water in the molten glass is, for example, about 20000 ppm as a range in which water can be contained as bound water. The water content for further enhancing the clarification effect of the present invention is more preferably 900 ppm or more.

In the present invention, the water content in the glass was determined by the infrared spectroscopy single band method, but the β-OH value determined by dividing the maximum value βmax of the absorbance by the thickness (mm) of the sample was 600 ppm. If the 0.33mm about ^-1, is about 0.165mm ^-1 in the case of 300ppm.

The technology of the present invention can be widely applied to the manufacture of architectural glass, vehicle glass, optical glass, medical glass, display device glass, cover glass for photovoltaic power generation and solar thermal power generation, and other general glass products.
The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2010-293999 filed on Dec. 28, 2010 are incorporated herein as the disclosure of the present invention. .

R1, R2, R3 ... flow path, G ... molten glass, GH ... liquid surface position of molten glass, 1 ... manufacturing apparatus, 2 ... melting tank, 3 ... first clarification tank, 3a ... first bottom wall, 3b: First side wall portion, 3d: Inlet side step portion (first step portion), 3e ... Drain out portion, 3f ... Inlet port, 3h ... Outlet port, 3i ... Drain out portion, 4 ... Second clarification Tank, 4a ... second bottom wall, 4b ... second side wall, 4d, 4e, 4f ... refractory brick (refractory), 4g ... inlet side step (second step), 4h ... inlet 4i, outlet, 4j, 4k, 4l, 4m, 4n, 4p, first convex portion, 4r, second convex portion, 4s, slit, 5 ... cooling tank, 5a, third bottom wall portion, 5b ... 3rd side wall part, 5e ... Inlet port, 5f ... Outlet port, 6 ... Molding device, 7, 57, 97 ... Clarification tank, 8 ... Electrode, 14, 56, 90 ... Glass melting furnace, 15 Inner cover, 16 ... cover assembly, 17 ... first plate assembly, 18 ... second plate assembly, 20 ... first bottom wall plate, 20c ... ear, 21 ... first side wall plate, 21a ... ear part, 22 ... first cover plate, 22A, 22B ... third cover plate, 23 ... second cover plate, 24 ... fourth cover plate, 25 ... second bottom wall plate, 25c ... ear Part, 26 ... second side wall plate, 26a ... ear part, 30, 31, 32 ... rivet, S1 ... glass melting step, S2 ... fining step, S3 ... molding step, S4 ... slow cooling step, S5 ... cutting step, G6 ... Glass product, 51 ... first cover piece, 52 ... second cover piece, 15A ... inner cover, 16A ... cover assembly, 60 ... bottom wall plate, 62 ... cover plate, 91 ... oxygen combustion burner.

Claims

A first molten glass flow path defined by the first bottom wall part and first side wall parts on both sides thereof, and a drain provided on the bottom wall part on the downstream side of the first molten glass flow path A first clarification tank comprising an out part and a molten glass heating means, wherein the length of the flow path of the first molten glass is larger than the height of the first side wall part;
A flow path that is provided following the first clarification tank and includes a second molten glass flow path defined by a second bottom wall portion and second side wall portions on both sides thereof, and the molten glass is in a uniflow state. A second clarification tank having a shape;
A cooling tank provided with a flow path of a third molten glass provided following the second clarification tank and partitioned by a third bottom wall part and third side wall parts on both sides thereof;
A clarification tank equipped with
The clarification tank according to claim 1, wherein, in the second molten glass flow path, the width of the second bottom wall portion perpendicular to the flow path direction is larger than the height of the second side wall portion.
The flow path shape of the second molten glass is set to satisfy Gr / Re 2 <11420, where Gr is the Grafhof number of the molten glass flowing through the flow path, and Re is the Reynolds number. 2. The clarification tank according to 2.
The heating means of the first clarification tank is a plurality of electrodes, and in the second clarification tank, the second molten glass flow path in the second bottom wall portion and the second side wall portions is made of refractory bricks. The clarification tank according to any one of claims 1 to 3, further comprising an inner surface cover made of a heat-resistant metal that covers the refractory brick on the flow path side.
The heating means of the first clarification tank is a burner, and in the first and second clarification tanks, the molten glass flow paths in the bottom wall and both side walls are made of refractory bricks, and the fire resistance on the flow path side The clarification tank according to any one of claims 1 to 3, further comprising an inner surface cover made of a heat-resistant metal that covers the brick.
The length of the first molten glass channel is 10-15 m, the length of the second molten glass channel is 4-14 m, and the flow rate through the molten glass channel is 100-1000 tons / day. The clarification tank according to any one of claims 1 to 5.
The clarification tank according to any one of claims 1 to 6, wherein a first step portion higher than the first bottom wall portion is formed at an uppermost stream end of the flow path of the first molten glass.
The clarification tank according to any one of claims 1 to 7, wherein a second step portion higher than the second bottom wall portion is formed at the most upstream end of the flow path of the second molten glass.
The first protrusion is formed on the downstream side of the flow path of the second molten glass from the corner of the second side wall and the second bottom wall. The clarification tank described in 1.
In the flow path of the second molten glass, on the upstream side of the formation position of the first protrusion, the second protrusion is further from the corner of the second side wall and the second bottom wall. The clarification tank according to claim 9 formed.
The inner surface cover includes a plurality of cover assemblies arranged along the flow direction of the molten glass so as to cover the molten glass flow channel side of the bottom wall and the side wall, and the cover assembly is formed of the bottom wall. 6. The apparatus according to claim 4, further comprising: a bottom wall plate that covers a portion; a side wall plate that covers the side wall portion; and a first cover plate that covers a butting region between the cover assemblies disposed along the flow path. Clarification tank.
The clarification tank according to any one of claims 1 to 11, wherein the cooling tank is provided with an inner surface cover made of a heat-resistant metal covering the molten glass flow path side in the third bottom wall portion and both third side wall portions. .
The heating means provided in the first clarification tank is composed of a plurality of electrodes erected in the first clarification tank, and these electrodes form a matrix along the flow direction of the molten glass. The clarification tank according to any one of claims 1 to 12, wherein a plurality of electrodes arranged in a row and in a row along the flow path direction of the molten glass are multiphase AC electrodes.
A glass melting furnace comprising the clarification tank according to any one of claims 1 to 13 and having a melting tank on the upstream side in the flow direction of the molten glass in the clarification tank.
Using the glass melting furnace according to claim 14, melting a glass raw material in a melting tank;
The step of discharging the heterogeneous substrate generated in the first clarification tank from the bottom part on the downstream side of the first clarification tank while clarifying by heating the molten glass that has come out of the melting tank in the first clarification tank,
Clarifying the flow of molten glass in the second clarification tank as a uniflow state;
Cooling the molten glass derived from the second clarification tank by the cooling tank;
The manufacturing method of the molten glass containing this.
In the uniflow state, when the graph Hof number of the molten glass is Gr and the Reynolds number is Re, the flow rate of the molten glass, the flow rate of the molten glass at the inlet and outlet of the molten glass so as to satisfy Gr / Re 2 <11420 are satisfied. The manufacturing method of the molten glass of Claim 15 obtained by setting a temperature change and the depth of a molten glass.
The method for producing molten glass according to claim 15 or 16, wherein the molten glass in the second clarification tank is not heated.
Heating in the first clarification tank is the temperature of the molten glass flowing through the first clarification tank, and the temperature on the downstream end side of the first clarification tank is higher than the temperature on the upstream end side of the first clarification tank. The method for producing molten glass according to any one of claims 15 to 17, which is carried out so as to be higher.
The step of producing the molten glass according to any one of claims 15 to 18, the step of forming the molten glass after cooling the molten glass to its glass forming temperature range, and gradually cooling the formed glass A method for producing a glass product, comprising: a step.
An apparatus for producing a glass product, comprising: the glass melting furnace according to claim 14; a forming means for forming the molten glass manufactured by the glass melting furnace; and a slow cooling means for gradually cooling the glass after forming.