JP7519025B2 - Glass Melting Furnace - Google Patents

Description

The present invention relates to the structure of a glass melting furnace for producing molten glass, which is the material for forming glass articles.

For example, in manufacturing lines for glass products such as plate glass and tubular glass, a glass melting furnace that produces molten glass is typically located at the most upstream position, and the molten glass produced in this melting furnace is typically formed into a desired shape.

The side wall of the above-mentioned glass melting furnace is provided with an inlet for feeding powdered glass raw material into the furnace, and the glass raw material is melted in the glass melting furnace by, for example, continuously feeding the glass raw material through this inlet, and molten glass is continuously produced (see, for example, Patent Document 1). Electrodes are also provided in the glass melting furnace, and the molten glass is heated by passing electricity through these electrodes (see, for example, Patent Document 2).

Here, the above-mentioned glass melting furnace is generally constructed by stacking refractory materials such as firebricks (see, for example, Patent Document 3). Therefore, the side walls of the glass melting furnace, including the part that defines the inlet, are usually made of multiple refractory materials.

JP 2010-222217 A JP 2015-51894 A JP 2008-1538 A

Recently, the electrodes used to electrically heat molten glass have been replaced with electrodes made of molybdenum, replacing the conventional tin electrodes. As a result of this replacement, the lifespan of the heating electrodes has improved significantly, and the factor that determines the lifespan of a glass melting furnace has shifted from the heating electrodes to the inlet and its surrounding area on the side wall. In other words, the inlet and its surrounding area are constantly subject to erosion from the glass raw materials, and as a result, there is an increasing need to replace the refractory material that defines the inlet before replacing the heating electrodes.

However, as mentioned above, the side walls of a glass melting furnace are generally constructed by stacking multiple refractory materials, so the refractory material that defines the inlet bears the weight of the refractory material located above it. Therefore, if an attempt is made to remove and replace only the refractory material that defines the inlet out of the multiple refractory materials that make up the side walls, the refractory material located above it may lose support and collapse. Therefore, when replacing the refractory material that defines the inlet, it is necessary to remove the refractory material located above first, which is very time-consuming.

In light of the above, the technical problem to be solved is to make it possible to easily replace only the necessary refractory materials, thereby extending the service life of glass melting furnaces.

The above-mentioned problems are solved by the glass melting furnace of the present invention. That is, this melting furnace has a plurality of side walls and a space partitioned by the plurality of side walls, one of which has an inlet for introducing glass raw materials into the space, and is capable of producing molten glass by melting the glass raw materials introduced into the space through the inlet. The inlet is characterized in that the first refractory material and the adjacent second refractory material above it are supported by a support portion.

In this way, in the glass melting furnace according to the present invention, the glass raw material inlet provided on one side wall that divides the space in the glass melting furnace is divided and formed by the first refractory material, and the first refractory material and the adjacent second refractory material above it are supported by the support part. This allows the weight of the second refractory material, which was previously supported by the first refractory material, to be supported by the support part instead of the first refractory material. Therefore, it is possible to easily replace the refractory material by removing the refractory material (first refractory material) that divides the inlet without removing the second refractory material located directly above the first refractory material. In addition, at this time, since the second refractory material is always supported by the support part, it is possible to quickly replace the necessary refractory material without performing additional work other than the replacement work.

In addition, in the glass melting furnace according to the present invention, a spacer may be provided between the first refractory material and the second refractory material.

By using a spacer in this way, the first and second fireproof materials can be kept out of contact, which prevents problems caused by friction between the first and second fireproof materials when replacing the first fireproof material, for example, and allows the fireproof material that defines the feed opening to be replaced more reliably.

In addition, in the glass melting furnace according to the present invention, the second refractory material may be supported by a spacer as a support part.

For example, the support part may have a structure that clamps the second fireproof material horizontally. However, since a large number of second fireproof materials are stacked together to form a side wall together with the first fireproof material, the overall structure becomes huge and heavy. For this reason, it is difficult to stably support a large number of second fireproof materials using clamping force alone. In contrast, if the second fireproof material is supported by a spacer as a support part, the second fireproof material can be directly supported from below, making it possible to stably support a large number of stacked second fireproof materials.

The glass melting furnace according to the present invention may further include a restricting portion capable of restricting the position of the refractory material constituting the side wall, and a support portion to which the restricting portion is connected. In this case, the spacer as the support portion may be fixed to the support portion.

By adopting a structure in which the spacer as a support is fixed to the support, all or part of the weight of the second refractory material is loaded onto the support via the spacer. This makes it even easier to replace the first refractory material. It also makes it possible to prevent the spacer from shifting out of position. Furthermore, because the support has traditionally been provided in the melting furnace, it is also possible to suppress increases in equipment costs.

In addition, in the glass melting furnace according to the present invention, the first refractory material may have better corrosion resistance against glass raw materials than the second refractory material.

When the glass melting furnace is in operation, the first refractory material that defines the inlet of the side wall is always in contact with the glass raw material, whereas the second refractory material located above the first refractory material is unlikely to come into contact with the glass raw material. Therefore, since the first refractory material has better corrosion resistance to glass raw material than the second refractory material, it is possible to reduce erosion by the glass raw material at the inlet and its surrounding area, and the frequency of replacement of the first refractory material can be reduced.

In addition, in the glass melting furnace according to the present invention, the first refractory material may be electrocast bricks. In this case, the electrocast bricks may be electrocast zirconia-based bricks.

In this way, by using electrocast bricks as the first refractory material, which is the refractory material that constitutes the side wall and is particularly concerned about contact with molten glass, it is possible to impart good corrosion resistance to the inlet and its surrounding area. In addition, by using zirconia-based electrocast bricks, it is possible to impart even better corrosion resistance.

In addition, in the glass melting furnace according to the present invention, the second refractory material may be a fired brick. In this case, the fired brick may be an alumina-based fired brick or an alumina-zircon-based fired brick.

The second refractory material is located above the first refractory material that defines the inlet, and therefore does not require as good heat resistance and corrosion resistance as the first refractory material. Therefore, by using relatively inexpensive fired bricks as the second refractory material, it is possible to keep production costs low while still providing the necessary physical and chemical properties.

As described above, the present invention makes it possible to easily replace only the necessary refractory materials, thereby extending the service life of the glass melting furnace.

FIG. 2 is a vertical cross-sectional view taken along line AA showing a main part of a glass melting furnace according to one embodiment of the present invention. 2 is a cross-sectional view taken along the line B-B of the glass melting furnace shown in FIG. 1. 2 is a view of the glass melting furnace shown in FIG. 1 as viewed from the direction of arrow C. FIG. 4 is a vertical cross-sectional view taken along the line D-D of the glass melting furnace shown in FIG.

One embodiment of the present invention will be described below with reference to Figures 1 to 4.

Figure 1 shows a vertical cross-sectional view of the main part of a glass melting furnace 1 according to this embodiment, and Figure 2 shows a horizontal cross-sectional view of the main part of the glass melting furnace 1. As shown in Figures 1 and 2, the glass melting furnace 1 includes a plurality of side walls 2 to 4, a space 5 defined by the plurality of side walls 2 to 4, an inlet 6 for introducing glass raw material M into the space 5, a bottom wall 7 defining the space 5 together with the plurality of side walls 2 to 4, and an electrode 8 provided on the bottom wall 7 for heating the molten glass Gm in the space 5. In this embodiment, the glass melting furnace 1 further includes a regulating member 9 as a regulating part for regulating the position of the side walls 2 to 4, and a support part 10 for fixing the regulating member 9.

Here, the glass raw material M to be fed into the space 5 is appropriately set in terms of the type and mixing ratio of raw materials to be mixed according to the various properties required for the glass (glass article) to be finally produced. An example of glass that can be produced here is alkali-free glass. This alkali-free glass does not substantially contain alkali metal oxides, in other words, the content of alkali metal oxides (Li2O, Na2O, K2O) in the glass composition is 1000 ppm (by mass) or less. Therefore, in this case, the glass raw material M is mixed and prepared so that the glass (glass article) to be finally produced is alkali-free glass. In addition, an example of the glass article to be produced is a glass plate formed by the overflow downdraw method or the float method. This glass plate is suitable for glass substrates and cover glass for displays.

The electrodes 8 may be made of known electrode materials such as tin and molybdenum, and among these, electrodes made of molybdenum or other materials are preferably used from the viewpoint of heat resistance and thus long life. The glass melting furnace 1 may be equipped with a burner for the purpose of assisting in heating the molten glass Gm or for the purpose of raising the temperature of the glass melting furnace 1 during start-up.

As shown in FIG. 2, the support pillars 10 are disposed in positions facing each other in the horizontal direction via the side walls 2 to 4. For the most upstream side wall 2 (hereafter simply referred to as side wall 2), a pair of support pillars 10, 10 are disposed to sandwich this side wall 2 in the horizontal direction. A restricting member 9 is disposed between each support pillar 10 and the side wall 2, and these restricting members 9 connect each support pillar 10 to the side wall 2. Similarly, restricting members 9 are disposed between the other side walls 3, 4 (and also the downstream side wall not shown), and these restricting members 9 connect each support pillar 10 to the side walls 3, 4.

A feeder 11 for feeding glass raw material M into the space 5 is disposed in the inlet 6. As the feeder 11, various raw material supply mechanisms such as a swing type, a conveyor type, a ladle type, and a screw type can be applied, and in this embodiment, a screw type feeder 11 is applied. Specifically, as shown in FIG. 1 etc., the feeder 11 is disposed at a predetermined position in the inlet 6 so that the tip 11a of the feeder 11 does not reach the space 5 of the glass melting furnace 1, in other words, the tip 11a of the feeder 11 is positioned within the inlet 6. In this way, the glass raw material M supplied from the feeder 11 is fed into the space 5.

In addition, in this embodiment, the inlets 6 are provided at three locations on the side wall 2 (see FIG. 2). A feeder 11 is provided in each of the inlets 6, which allows the glass raw material M to be simultaneously fed into the space 5 from multiple locations (three locations in this case).

Next, we will explain the detailed structure of the side wall 2, focusing on the area around the insertion port 6.

Figure 3 is a front view of the side wall 2 (a view of the side wall 2 in the direction of the arrow C in Figure 1). As shown in Figure 3, the side wall 2 is composed of a plurality of fireproof materials 12-15. On the other hand, the side wall 2 is provided with an inlet 6. Therefore, the inlet 6 is partitioned by the first fireproof material 12 arranged around the inlet 6 among the fireproof materials 12-15 constituting the side wall 2. In this embodiment, the first fireproof material 12 has a through hole 12a, and when the first fireproof material 12 is stacked together with the other fireproof materials 13-15 to form the side wall 2, the through hole 12a of the first fireproof material 12 partitions the inlet 6. In other words, the inlet 6 is partitioned by one first fireproof material 12. Therefore, when three inlets 6 are arranged side by side in the horizontal direction as shown in Figure 2, three first fireproof materials 12 having through holes 12a are arranged adjacent to each other in the horizontal direction. In FIG. 3, three first refractory materials 12 are arranged at the same height on the side wall 2 while being in contact with each other in the horizontal direction. In FIG. 3, the first refractory material 12 is generally box-shaped, but it may have a shape other than a box shape as long as it can be stacked together with the other refractory materials 13 to 15 to form the side wall 2. In addition, the shape of the through hole 12a is arbitrary as long as it allows the feeder 11 to be introduced into the inlet 6 and the glass raw material M to be supplied to the space 5.

Above the first refractory material 12, a large number of refractory materials are stacked and together with the first refractory material 12 form the side wall 2. Among these, the first refractory material 12 and the adjacent second refractory material 13 above it are supported by the support portion 16. In this embodiment, a spacer 17 is disposed between the first refractory material 12 and the second refractory material 13. This spacer 17 extends beyond both horizontal ends 12b of the three first refractory materials 12 that define the inlet 6. And, at both horizontal ends of this spacer 17, as shown in FIG. 4, flange portions 17a located outside the glass melting furnace 1 are provided, and these flange portions 17a are fixed (for example, by welding or bolting) to the support portion 10 arranged to sandwich the side walls 3 and 4 in the horizontal direction. By fixing the spacer 17 to the support portion 10 via the flange portion 17a in this way, the spacer 17 functions more effectively as the support portion 16 of the second refractory material 13. The spacer 17 may be fixed to the support pillars 10 arranged to sandwich the side wall 2 horizontally. This allows the spacer 17 to be fixed even more firmly. In addition, the flanges 17a in this embodiment are provided in the portion of the spacer 17 that corresponds to the support pillars 10 in the longitudinal direction, but they may be provided over the entire longitudinal area of the spacer 17. This improves the strength of the spacer 17, reducing bending deformation of the spacer 17.

In addition, in consideration of contact with the molten glass Gm (and thus leakage), it is preferable that the first refractory material 12 is bonded to adjacent refractory materials, such as the first refractory material 12 and the third refractory material 14 adjacent in the horizontal direction, or the fourth refractory material 15 adjacent below, with a bonding agent such as mortar. Based on the same idea, it is also preferable that adjacent fourth refractory materials 15 are bonded to each other. On the other hand, since the second refractory material 13 is located above the inlet 6, from the viewpoint of preventing leakage of the molten glass Gm, the second refractory materials 13 do not necessarily have to be bonded to each other. On the other hand, in consideration of a situation in which gaps occur between adjacent second refractory materials 13 during expansion, it is preferable that the second refractory materials 13 are bonded to each other.

On the other hand, when the spacer 17 supports the second refractory material 13 from below as the support portion 16, the spacer 17 is required to have not only heat resistance but also high strength and rigidity. For this reason, the spacer 17 is preferably made of a metal material, more preferably made of a steel material, and even more preferably made of a stainless steel material. In this case, taking into consideration the difference in the linear expansion coefficient between the spacer 17 and each of the refractory materials 12 to 14, it is preferable that the spacer 17 and each of the refractory materials 12 to 14 are not joined to each other.

Furthermore, each of the refractory materials 12 to 15 may have the same material composition, or at least some of the refractory materials, for example the first refractory material 12 and the second refractory material 13, may have different material compositions. For the first refractory material 12 and the second refractory material 13, for example, zircon-based, alumina-zircon-based, silica-based, mullite-based, or clay-based bricks can be used. These bricks may be electrocast bricks or fired bricks.

The first refractory material 12 is preferably more resistant to corrosion against the glass frit M than the second refractory material 13. In particular, when the tip 11a of the feeder 11 is located inside the inlet 6 as in this embodiment, the glass frit M discharged from the tip 11a of the feeder 11 is constantly in contact with the inner surface (here, the inner surface of the through hole 12a) of the first refractory material 12 that defines the inlet 6, and the glass frit M is charged into the space 5. For the above reasons, it is preferable to use zirconia-based electrocast bricks as the first refractory material 12. From the viewpoint of preventing the first refractory material 12 from being damaged by thermal shock after replacement, it is preferable that the first refractory material 12 has thermal shock resistance, and it is preferable to use, for example, alumina-zircon-based fired bricks. On the other hand, it is preferable to use alumina-zircon-based fired bricks or alumina-based electrocast bricks as the second refractory material 13.

As described above, in the glass melting furnace 1 according to this embodiment, the inlet 6 for the glass raw material M provided in one of the side walls 2 that defines the space 5 in the glass melting furnace 1 is defined by the first refractory material 12, and the first refractory material 12 and the adjacent second refractory material 13 above it are supported by the support portion 16. This allows the weight of the second refractory material 13, which was previously supported by the first refractory material 12, to be supported by the support portion 16 instead of the first refractory material 12. Therefore, it is possible to easily replace the first refractory material 12 by removing the first refractory material 12 that defines the inlet 6 without removing the second refractory material 13 located directly above the first refractory material 12. In addition, at this time, since the second refractory material 13 is always supported by the support portion 16, it is possible to quickly replace the necessary refractory material (first refractory material 12) without performing any additional work other than the replacement work.

In addition, in this embodiment, a spacer 17 is provided as a support portion 16 between the first refractory material 12 and the second refractory material 13. As a result, when one first refractory material 12 is removed, the weight of the second refractory material 13 and other materials arranged above it is distributed to the horizontally adjacent first refractory material 12 and third refractory material 14 via the spacer 17 as a support portion 16. This makes it possible to stably support a large number of second refractory materials 13 stacked above the removed first refractory material 12.

In addition, in this embodiment, the spacer 17 as the support portion 16 is fixed to the support portion 10. As a result, part or all of the weight of the second refractory material 13 is loaded onto the support portion 10 via the spacer 17. This makes it possible to replace the first refractory material 12 even more easily. It is also possible to prevent the spacer 17 from shifting out of position. Furthermore, since the support portion 10 has been conventionally provided in the melting furnace 1, an increase in equipment costs can be suppressed. From the viewpoint of making it easier to replace the first refractory material 12, it is preferable that all of the weight of the second refractory material 13 is loaded onto the support portion 10, the third refractory material 14, etc. via the spacer 17. In other words, it is preferable to provide a gap between the first refractory material 12 and the spacer 17. During operation, the gap may be sealed with a blanket or the like.

In addition, in this embodiment, a through hole 12a is provided in the first refractory material 12, and this through hole 12a defines and forms the inlet 6 for the glass raw material M. By forming the inlet 6 in this manner, the number of refractory materials (first refractory materials 12) to be replaced can be further reduced, making it possible to further facilitate and speed up the replacement work.

Although one embodiment of the present invention has been described above, the glass melting furnace according to the present invention is not limited to the above embodiment and can take various forms within the scope of the present invention.

For example, in the above embodiment, a spacer 17 is disposed between the first refractory material 12 and the second refractory material 13, and the spacer 17 is used as the support portion 16 of the second refractory material 13, but of course other configurations are possible. For example, although not shown, a pair of clamping members may be provided to sandwich the second refractory material 13 horizontally, and the second refractory material 13 may be constantly clamped by these clamping members, thereby imparting to the second refractory material 13 a supporting force sufficient to support the weight of the second refractory material 13. Alternatively, the second refractory material 13 may be supported by clamping it using a pair of regulating members 9 shown in FIG. 2. In this case, the presence or absence of the spacer 17 does not matter.

In addition, in the above embodiment, the spacer 17 is fixed to the support portion 10, but of course other configurations are possible. For example, although not shown, the spacer 17 may be fixed to a structure other than the support portion 10 to prevent the spacer 17 from shifting from its position as the support portion 16. Alternatively, the spacer 17 may be disposed between the first refractory material 12 and the second refractory material 13 without being fixed to the support portion 16 or the like.

In the above embodiment, the first fireproof material 12 is provided with a through hole 12a, and the through hole 12a is used to define the inlet 6. However, the inlet 6 may be defined in other ways. For example, although not shown, the first fireproof material 12 may be made of a plurality of divided fireproof materials. More specifically, the inner surface of the rectangular inlet 6 may be divided into four flat surfaces, and each divided flat surface may be defined by the corresponding four fireproof materials.

Reference Signs List 1 Glass melting furnace 2 Side walls 3, 4 Side walls 5 Space 6 Input port 7 Bottom wall 8 Electrode 9 Regulating member 10 Support 11 Feeder 11a Tip 12 First refractory material 12a Through hole 13 Second refractory material 14 Third refractory material 15 Fourth refractory material 16 Support 17 Spacer 17a Flange Gm Molten glass M Glass raw material

Claims (4)

A glass melting furnace comprising a plurality of side walls and a space partitioned by the plurality of side walls, one of the plurality of side walls having an inlet for introducing glass frit into the space, capable of melting the glass frit introduced into the space through the inlet to produce molten glass,
The fireproofing material constituting the side wall may further include a restricting portion capable of restricting a position of the fireproofing material constituting the side wall, and a support portion to which the restricting portion is connected.
The refractory material includes a first refractory material and a second refractory material,
The inlet is partitioned by the first refractory material disposed around the inlet,
the first refractory material and the second refractory material adjacent thereto above are supported by a spacer disposed between the first refractory material and the second refractory material;
A glass melting furnace, characterized in that a part of the spacer protrudes toward an outer surface of the side wall to form a protruding portion , and the protruding portion of the spacer is fixed to the support portion. The glass melting furnace according to claim 1, wherein the first refractory material has better corrosion resistance against glass raw materials than the second refractory material. The glass melting furnace according to claim 1 or 2, wherein the first refractory material is a zirconia-based electrocast brick. The glass melting furnace according to any one of claims 1 to 3, wherein the second refractory material is an alumina-based fired brick or an alumina-zircon-based fired brick.

Images