JP5120261B2 - Manufacturing method of glass sheet - Google Patents

Description

  The present invention relates to a method for producing a glass sheet by a float process, more specifically, a method for producing a glass sheet by removing foreign substances such as molten tin adhering to a glass ribbon, a method for removing foreign substances such as molten tin, And an apparatus for removing foreign matter such as molten tin.

In glass sheets such as plate glass for construction, plate glass for automobiles, and plate glass for display, further higher quality and cost reduction are required. Although there are several factors that hinder high quality and low cost, tin, tin oxide, and the like generated when molten tin in a molten tin bath (float bath) adheres to a glass sheet are often problematic.
In the production of a glass sheet by the float process, the molten glass is formed into a continuous sheet on the molten tin surface of the molten tin bath to form a continuous glass sheet having a predetermined width (hereinafter referred to as a glass ribbon). The glass sheet is drawn out and further cut into a predetermined size. In this case, the glass ribbon is pulled out by lifting the glass ribbon with a roll usually called a lift-out roll. The area where the lift-out roll exists is hereinafter referred to as a lift-out area. The drawn glass ribbon is then gradually cooled in a slow cooling process called a layer. The zone where the cooling is performed is hereinafter referred to as a layer region, and a roll that supports and conveys the glass ribbon in the layer region is hereinafter referred to as a layer roll. Since molten tin in the float bath is easily oxidized, the atmosphere in the float bath is kept in a reducing atmosphere. The lift-out area is usually kept in a reducing atmosphere.

  In the manufacturing process of the glass sheet, the molten tin tends to adhere to the lower surface of the glass ribbon drawn from the surface of the molten tin. The lift-out roll is not intended to remove the molten tin attached to the lower surface of the glass ribbon, but the molten tin attached to the lower surface of the glass ribbon comes into contact with the lower surface of the glass ribbon when the roll surface comes into contact with the lower surface of the glass ribbon. Since it moves, there exists an effect | action which removes the molten tin adhering to the glass ribbon lower surface (refer patent document 1). However, removal of the molten tin by the lift-out roll is insufficient, and the molten tin tends to remain on the lower surface of the glass ribbon. The lift-out roll is made of iron or ceramics and does not necessarily contact the entire surface of the glass ribbon. Furthermore, although the molten tin adhering to the lift-out roll is removed from the roll surface, it often remains on the roll surface, and the remaining molten tin may reattach to the lower surface of the glass ribbon. The molten tin remaining on the glass ribbon may further contaminate the layer roll.

  The molten tin remaining on the surface of the glass ribbon is easily oxidized, and the generated tin oxide has an extremely high melting point. Therefore, it is difficult to remove the tin oxide if it adheres to the surface of the glass ribbon. In addition to tin oxide, tin compounds such as sulfides may be generated due to impurities in the atmosphere in the float bath, molten tin, impurities in the glass, and the like. The mixture of molten tin and tin compounds removed in the lift-out zone is called dross. When these foreign matters are cooled while attached to the glass ribbon, it is difficult to remove the foreign matters from the glass sheet.

  As described above, foreign matters such as tin and tin oxide adhering to the lower surface of the glass ribbon become defects and cause deterioration of the quality of the glass sheet and production yield. In some cases, it is necessary to remove the foreign matter from the glass ribbon or the glass sheet after the slow cooling. Therefore, a new step of removing the foreign matter may be provided, which further increases the cost. In addition, tin and tin oxide remaining on the glass ribbon surface and roll surface may damage the glass ribbon surface, and further cause cracks in slow cooling and subsequent processes due to the scratches, which in turn reduces the production yield. It can also be a cause.

JP 11-335127 A

  The present invention has been made in view of the above, and foreign matter adhering to the surface of the glass ribbon is removed from the surface in a stage where the glass ribbon is in a high temperature state (that is, a stage where tin which is a main foreign matter is melted). The purpose is to remove directly. In addition, since the glass ribbon surface is relatively soft at that stage, it is necessary that the member that contacts the glass ribbon surface to wipe off foreign matter has heat resistance and can be flexibly contacted with the glass ribbon surface without a gap. .

  The present invention relates to a method for producing a glass sheet by a float method, wherein a foreign material such as molten tin adhering to the surface of the glass ribbon is directly removed from the surface of the glass ribbon by a removing member that comes into contact with the surface of the glass ribbon. The present invention relates to a method for removing the foreign matter from the above and a foreign matter removing device suitable for these methods.

(1) In a method for producing a glass sheet by a float process, a removing member made of a heat-resistant fiber sheet is brought into contact with the surface of the glass ribbon drawn out from the molten tin bath and in the melting temperature range of the tin, A method for producing a glass sheet, characterized by sweeping and removing foreign matter such as adhering molten tin.
(2) The method according to (1), wherein the removal member is in a non-oxidizing atmosphere.
(3) The method according to (1) or (2) above, wherein the heat-resistant fiber sheet is a felt-like sheet or a woven or non-woven sheet made of at least one selected from carbon fibers and silica fibers.
(4) The method according to (1), (2) or (3), wherein the removing member is urged toward the glass ribbon surface by an elastic force or gas pressure.

(5) The manufacturing method of the glass sheet in any one of said (1)-(4) which abuts the said removal member on the lower surface of a glass ribbon.
(6) In the process of producing a glass sheet by the float method, a foreign matter such as molten tin drawn from the molten tin bath and adhering to the surface from the surface of the glass ribbon in the melting temperature range of the tin is removed. And
A method for removing foreign matter such as molten tin, wherein a removing member made of a heat-resistant fiber sheet is brought into contact with the surface of the glass ribbon and the foreign matter such as molten tin is swept away from the surface of the glass ribbon.
(7) The removal method according to (6), wherein the removal member is in a non-oxidizing atmosphere.

(8) A removal device that removes foreign matters such as molten tin drawn from the molten tin bath and adhered to the surface of the glass ribbon in the melting temperature range of the tin in the process of producing the glass sheet by the float process. There,
The removing device includes a removing member that comes into contact with the surface of the glass ribbon and wipes and removes foreign matters such as molten tin from the surface of the glass ribbon, and a fixing member that supports the removing member. A removing device characterized in that the removing member is formed of a heat-resistant fiber sheet.
(9) The removing device according to (8), wherein the fixing member includes an elastic body that biases the removing member toward the surface of the glass ribbon.
(10) The removing device according to (8), wherein the fixing member has a gas passage for biasing the removing member to the surface of the glass ribbon with a gas pressure.
(11) The removal member has a mountain shape in a state where it is supported by a fixing member, and the top of the mountain shape is in contact with the surface of the glass ribbon, as described in (8), (9) or (10). Removal device.
(12) The heat-resistant fiber sheet according to any one of (8) to (11), wherein the heat-resistant fiber sheet is a felt-like sheet or a woven or non-woven sheet made of at least one selected from carbon fibers and silica fibers. Removal device.

  According to the method for producing a glass sheet of the present invention, foreign matters such as molten tin adhering to the glass ribbon surface can be directly removed from the glass ribbon surface by a removing member. As a result, foreign matter adhering to the roll in contact with the glass ribbon downstream from the removing member can be reduced, so that foreign matter from these rolls can be prevented from reattaching to the glass ribbon surface. Moreover, not only the foreign substances adhering to the lower surface of the glass ribbon, but also removing the foreign substances adhering to the upper surface of the glass ribbon (brick scraps and other foreign objects dropped from the upper part of the float bath) by providing a removing member on the upper surface of the glass ribbon. You can also.

  By the above effects, the defects of the glass sheet due to the foreign matter such as tin and tin oxide adhered to the glass ribbon surface are reduced, the scratches on the glass ribbon surface due to the foreign matter adhered to the roll are reduced, Quality and manufacturing costs can be reduced.

It is a figure which shows the cross section of the removal apparatus of embodiment. It is a figure which shows the cross section of the manufacturing equipment of the glass sheet containing the removal apparatus of embodiment. It is a figure which shows the cross section of the removal apparatus concerning another form of implementation. It is a figure which shows the cross section of the removal apparatus concerning another form of implementation. It is a figure which shows the cross section of the removal apparatus concerning another form of implementation. It is sectional explanatory drawing which shows an example in the case of horizontally moving the removal apparatus in embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Molten tin bath, 2 ... Molten tin, 3 ... Glass ribbon, 4 ... Removal member, 5 ... Fixing member, 6 ... Plate-shaped body, 7 ... Removal apparatus, 8 ... Lift-out roll, 9 ... Lift-out roll, 10 DESCRIPTION OF SYMBOLS ... Lift-out roll, 11 ... Layer roll, 12 ... Layer, 13 ... Drive belt, 14 ... Drive motor, 15 ... Drive device, A ... Space across the width direction of a glass ribbon between a removal member and a fixing member, B ... through hole, C ... direction of ribbon glass travel, D ... space, E ... floor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings (FIGS. 1 to 6). FIG. 1 shows a cross section of a removal apparatus according to an embodiment. FIG. 2 shows a cross section of a glass sheet manufacturing facility including the removing device in the embodiment. 3 to 5 show cross sections of a removing apparatus according to another embodiment. FIG. 6 shows an example of horizontally moving the removal device. In the following description, “downstream” refers to the direction opposite to the molten tin bath with reference to the moving direction of the glass ribbon (the direction indicated by the arrow C in FIG. 1), and the opposite direction is referred to as upstream.

  The removing device 7 whose cross section is shown in FIG. 1 is a device that removes foreign matter adhering to the lower surface of the glass ribbon 3. The glass ribbon 3 formed on the molten tin bath is drawn from the molten tin bath and moves in the direction indicated by C. The removing device 7 includes a removing member 4 that contacts the lower surface of the glass ribbon 3 and a fixing member 5 that supports the removing member. Both the removing member 4 and the fixing member 5 are arranged in the width direction of the glass ribbon 3 (perpendicular to the paper surface). It is an elongated body. The removal member 4 is made of a heat-resistant fiber sheet, and both ends of the removal member 4 in the width direction (a direction orthogonal to the longitudinal direction of the long body) are attached to the fixing member 5 and bulges between the both ends in a mountain shape (convex shape). The top portion is in contact with the lower surface of the glass ribbon 3. The fixing member 5 is a rectangular pipe-like long body, and the hollow space D and the internal space A of the portion of the removal member 4 that rises in a mountain shape are communicated with each other through a through hole (or slit) B. By introducing pressurized gas into the hollow portion D of the fixing member 5, the removal member 4 can be raised in a mountain shape, and the contact pressure and contact area of the removal member 4 with respect to the glass ribbon 3 can be adjusted by the expansion pressure. For this reason, it is preferable that the edge part of the removal member 4 and the fixing member 5 is obstruct | occluded. Fixing of the removing member 4 to the fixing member 5 can be performed by screwing, pasting, sandwiching with a backing plate, or the like. Foreign matter such as molten tin adhering to the lower surface of the glass ribbon 3 is removed from the lower surface of the glass ribbon 3 by the removing member 4, and the removed foreign matter is usually upstream of the removing member 4 (opposite to the traveling direction C of the glass ribbon). To the side).

  FIG. 2 shows a cross section of a glass sheet manufacturing facility in which the removing device 7 as described above is provided in the lift-out region. In the manufacturing method of the glass sheet by the float method, the process of mainly melt | dissolving a raw material in the melting kiln which is not shown in figure and making molten glass into the flat plate on the molten tin 2 of the molten tin bath 1 is carried out. , A step of drawing the glass ribbon 3 from the molten tin bath 1 by lift-out rolls 8, 9, 10, a step of slowly cooling the glass ribbon 3 while moving the glass ribbon with the layer roll 11 in the layer region 12 so as not to leave strain on the glass ribbon 3 It consists of. These processes may be performed by normal facilities and are not affected by the installation of the removing device 7. In FIG. 2, the removing device 7 is provided on the downstream side of the liftout roll 10 which is the most downstream in the liftout region.

  The removal device 7 can be provided at any position in the lift-out area of the above process or in the upstream portion in the layer area 12. Here, the upstream portion in the layer region 12 refers to a region in the layer region 12 at a temperature equal to or higher than the melting point of tin (tin melting temperature region). The lift-out region is usually in the melting temperature region of tin. Therefore, as long as it is in this temperature range, the removal device 7 is, for example, upstream of the lift-out roll 8, between the lift-out rolls 8 and 9, between the lift-out rolls 9 and 10, and within the layer area 12. It can also be provided on the upstream side of the upstream layer roll 11, between the layer roll 11 and the next layer roll 11, or the like. Moreover, the removal apparatus 7 can also be provided in two or more places of these positions.

  FIG. 3 is an enlarged cross-sectional view of the removing device 7 in FIG. 2, and is a removing device having the same configuration as that shown in FIG. The plate-like body 6 is attached to the upstream side of the upper portion of the fixing member 5, exists in the internal space A that rises in a mountain shape of the removal member 4, and supports the removal member 4 from the back surface. The plate-like body 6 elastically supports the removing member 4 so that the pressure at the time of contact between the removing member 4 and the lower surface of the glass ribbon 3 can be adjusted. The long thing which continues in the width direction may be provided, and you may provide intermittently. The contact pressure can be adjusted by changing the thickness of the plate-like body 6. The plate-like body 6 in FIG. 3 is substantially J-shaped and a portion having a curvature of the bottom portion of the substantially J-shape is in contact with the back side of the mountain-shaped portion of the removing member 4.

  The plate-like body 6 can swell the removing member 4 in a mountain shape and adjust the shape thereof to adjust the contact area of the removing member 4 with respect to the glass ribbon 3. Further, by adjusting the position of the removing member 4 in the thickness direction, the contact pressure of the removing member 4 with respect to the glass ribbon 3 can be adjusted using the elasticity of the removing member 4 in the thickness direction. In addition, the plate-like body 6 can be made of an elastic body, and the contact area and the contact pressure can be adjusted using the elasticity of the plate-like body 6. FIG. 3 shows an example using a plate-like body 6 having elasticity. The plate-like body 6 may not have elasticity. The cross-sectional shape of the plate-like body 6 is not limited to the shape shown in FIG. 3, and may have a rectangular shape or other shapes. FIG. 4 shows an example in which a plate-like body 6 having a substantially rectangular cross section is used. Further, the plate-like body 6 can be further attached to the downstream side of the upper portion of the fixing member 5, and FIG. 5 is an example in which the plate-like body 6 is attached to both the upstream side and the downstream side of the upper portion of the fixing member 5. In the removing device 7 provided with these plate-like bodies 6, it is not necessary to raise the removing member 4 in a mountain shape with the gas pressure. However, also in the removing device 7 provided with these plate-like bodies 6, it is preferable that the removing member 4 is raised in a mountain shape by the gas pressure. This is because it becomes easier to adjust the contact area and the contact pressure by the gas pressure.

  The removal member 4 is easy to repel molten tin and the glass ribbon surface is also relatively easy to repel molten tin. Therefore, the removal member 4 has a relative speed to the glass ribbon to sweep away and remove foreign matters on the glass ribbon surface. (Wipe off). In order to effectively remove foreign matters, it is preferable that the removing member and the glass ribbon come into contact with each other with a relative speed. Since the glass ribbon moves in the traveling direction shown by C in FIG. 2 at a predetermined traveling speed (hereinafter referred to as Gv), both of them have a relative speed Gv even if the removing member 4 is fixed. It touches. This relative speed can be varied as desired. In order to make the relative speed slower than Gv, it is preferable to move the removing member 4 in the same direction as the glass ribbon moving direction at a speed slower than Gv. In order to make the relative speed faster than Gv, it is preferable to move the removing member 4 in the direction opposite to the moving direction of the glass ribbon. Moreover, the removal member 4 can also be reciprocated in the direction opposite to the moving direction of the glass ribbon. FIG. 6 shows an example of horizontally moving the removing device. 6 is attached to the driving belt 13 of the driving device 15 and reciprocates in parallel with the traveling direction of the glass ribbon 3 at a speed different from the traveling speed of the glass ribbon by a driving motor 14 fixed on the floor E. It is something to be made.

  In the present invention, the removing device is not limited to the illustrated one. For example, a roll-shaped removing device or a continuous belt-shaped removing device that rotates on an axis parallel to the width direction of the glass ribbon can be used as in the lift-out roll. As the roll-shaped removing device, for example, a roll-shaped removing device having a round pipe-shaped fixing member and a heat-resistant fiber sheet layer (removing member) provided on the surface thereof can be used. A through-hole or a slit may be provided in the round pipe-shaped fixing member, and gas may be supplied from the fixing member to apply a gas pressure to the heat-resistant fiber sheet layer. As a continuous belt-shaped removing device, for example, the surface of the belt 13 driven by the driving device 15 shown in FIG. 6 is formed of a heat-resistant fiber sheet, and this belt is used as a removing member so as to contact the glass ribbon surface. The removal device can be used. It is preferable to remove the foreign matter on the surface of the glass ribbon by driving the roll or belt in the removing device so as to have a relative speed with the glass ribbon.

  The removing member is preferably in continuous contact with the glass ribbon over substantially the entire length in the width direction. However, the present invention is not limited to this, and when there is a place where foreign matter is likely to adhere to the glass ribbon, it can be used by contacting only that portion. For example, when a foreign substance tends to adhere to both ends in the width direction of the glass ribbon, a removal member that contacts only that portion can be used. Moreover, it is preferable that the removal member is in contact with the glass ribbon in a direction orthogonal to the traveling direction of the glass ribbon over almost the entire length in the width direction. However, the present invention is not limited to this, and the glass ribbon can be brought into contact with the traveling direction of the glass ribbon at an angle other than a right angle.

  The removing member can be brought into contact with the upper surface of the glass ribbon to remove foreign substances adhering to the upper surface of the glass ribbon. For example, the removing member can be driven in the width direction of the glass ribbon to move the foreign matter to the end portion in the width direction of the glass ribbon and removed from the glass ribbon. Moreover, when a foreign material adheres to a removal member, the foreign material on the upper surface of a glass ribbon can be removed by replacing the removal member at an appropriate interval.

  In this invention, a removal member consists of a heat-resistant fiber sheet. As the heat-resistant fiber, a fiber made of a material capable of withstanding a temperature of 750 ° C. (approximately the temperature of molten glass), particularly about 1000 ° C. is preferable. Specifically, for example, inorganic fibers such as carbon fiber, silica fiber, alumina fiber, silicon carbide fiber, metal fiber, etc. Among them, carbon fiber and silica fiber are preferable, especially the hardness is low and the glass ribbon is not easily damaged, and further, molten tin is used. Repelling carbon fibers are preferred. As the fiber sheet, a felt-like sheet or a woven or non-woven sheet is preferable. Specifically, for example, a carbon fiber felt sheet (carbon felt) or a carbon fiber woven fabric (carbon cloth) can be used. The heat-resistant fiber sheet may be a fiber sheet composed of two or more kinds of inorganic fibers of different materials. Even if the carbon fiber remains on the lower surface of the glass ribbon, it is preferable because it does not burn out in a relatively high-temperature oxidizing atmosphere, for example, in the latter half of the layer region, and does not cause defects such as dirt.

  Although the thickness of a removal member is not specifically limited, In order to give a softness | flexibility, it is preferable that it is 5 mm or more. The upper limit of the thickness is not particularly limited, but in the case of gas supply described later, 30 mm, particularly 15 mm is preferable from the viewpoint of pressure loss with respect to gas. In forming the removal member, only the felt-like sheet or a plurality of woven or non-woven fabrics may be stacked, and further, the felt-like sheet may be combined with the woven or non-woven fabric.

  The removing member is brought into contact with the surface of the glass ribbon after being drawn out of the molten tin bath and in the tin ribbon melting temperature region. The melting temperature of tin is about 230 ° C. The melting temperature range of tin is typically in the range of 230 ° C to 230 + 10 ° C. Therefore, the position where the removal member contacts the glass ribbon is in a temperature range higher than the melting point of the tin. In this temperature range, the main foreign substance, tin, is in a liquid temperature range, and therefore the foreign substance can be easily wiped off by the removing member. A high melting point foreign material such as tin oxide is usually carried on molten tin and can be easily wiped off with molten tin. Even a high melting point foreign matter not supported on molten tin can be wiped off in the same manner because it is not firmly adhered to the surface of the glass ribbon due to the high temperature of the glass ribbon. As described above, the lift-out region is usually in the temperature region above the melting temperature of tin, and the upstream region in the layer region is also usually in the temperature region above the melting temperature of tin. Therefore, it is preferable that the removing member is brought into contact with the surface of the glass ribbon in the lift-out region or the upstream region of the layer region, particularly in contact with the surface of the glass ribbon in the lift-out region.

  Even if the contact position of the removing member is within the melting temperature range of tin, if there is a large amount of high melting point foreign matter (particularly tin oxide), it may be difficult to wipe off sufficient foreign matter. Since molten tin is easily oxidized, it is not preferable that oxidation of molten tin, which is a foreign substance, proceeds before contact of the removal member. Therefore, it is preferable that at least the contact position of the removal member and the atmosphere upstream thereof where the glass ribbon exists is in a reducing gas atmosphere or an inert gas atmosphere (the two atmospheres are also referred to as non-oxidizing atmospheres). The lift-out area is usually maintained in a reducing gas atmosphere similar to a float bath. Further, the portion into which the gas in the lift-out region upstream of the layer region flows is usually in a reducing gas atmosphere or an inert gas atmosphere. Therefore, as long as the contact position of the removal member is in these regions, it is considered that oxidation of molten tin does not proceed easily. Also, especially in the upstream of the layer area, there may be a temporary oxidizing atmosphere. Therefore, the glass ribbon is present, the abutting position of the removing member and the reducing gas is supplied to the upstream of the atmosphere. Can be kept in a non-oxidizing atmosphere.

  On the other hand, as shown in the figure, the removal device is preferably a removal device having a structure in which the removal member is raised in a mountain shape by gas pressure. In this case, a pressurized gas introduced from the fixing member 5 to the inner side A of the removing member is used. This pressurized gas may come into contact with molten tin that is a foreign substance, and therefore, this pressurized gas is preferably composed of a non-oxidizing gas (that is, a reducing gas or an inert gas). Furthermore, when the removing member is made of a material that is easily oxidized, such as carbon fiber, it is not preferable that the removing member is in an oxidizing atmosphere. Also from this viewpoint, it is almost essential that the pressurized gas is made of a non-oxidizing gas. Also, even if the removal member is in a reducing atmosphere, the oxygen concentration may temporarily increase, so that reducing gas as a pressurized gas is used to prevent the removal member from being shortened. Is preferred. The supply pressure of these gases is preferably set in consideration of pressure loss. If the gas pressure is too low, the contact pressure of the removing member with respect to the glass ribbon surface is lowered, and the effect of removing foreign substances may be reduced. On the other hand, if it is too high, there is a risk that the foreign matter adhering to the removal member will reattach to the glass ribbon surface. The gas supply amount may vary depending on the structure of the removing device, but in a normal case, 10 to 100 liters / minute per 1 m in the width direction is appropriate. Note that supplying this amount of gas also has the effect of cooling the removal member and the fixing member.

  The oxygen concentration in the non-oxidizing gas or non-oxidizing atmosphere is preferably 1% or less, particularly preferably 1000 ppm or less. As the reducing gas, hydrogen, acetylene, or an inert gas containing these is preferable. The inert gas is preferably nitrogen gas or argon gas. The reducing atmosphere is preferably a hydrogen-containing nitrogen gas atmosphere similar to the float bath atmosphere.

  The material of the fixing member in the removing device is not limited as long as it has heat resistance. Usually made of metal, carbon, ceramics and other materials. A metal such as stainless steel is preferable. The material of the plate-like body mounted on the fixing member is similarly made of a heat resistant material, and is preferably metal, carbon, ceramics, or the like. The elastic plate is preferably a metal such as stainless steel. Carbon or the like can also be used as the plate-like body having no elasticity.

  A removal device was fabricated to confirm the effectiveness of the present invention. Furthermore, an experiment was conducted in which the removal device was placed in a glass sheet manufacturing facility using a float process to confirm the effect of removing tin and tin oxide. The removal device used for the experiment was installed on the layer side of the liftout roll closest to the downstream of the plurality of liftout rolls. The removing member was brought into contact with 20 cm (the length in the width direction of the glass ribbon) at one end of the lower surface of the glass ribbon for 20 days during the production period of the glass sheet. During that period, the surface of the glass ribbon that passed over the removal member was visually inspected at a frequency of once every 2 hours (total number of inspections: 240) under a high-intensity light source used for normal quality inspection.

The removal member used in this experiment was a felt-like carbon fiber having a thickness of 10 mm and a bulk density of 0.10 g / cm ³ of F-210G (manufacturer: Kureha Co., Ltd.) under the trade name KRECA G FELT as fibrous carbon. . This was used by processing so that the length of the portion in contact with the glass ribbon was 200 mm and the width was 100 mm. As the fixing member, a square pipe made of stainless steel having a 20 mm square and a thickness of 1.2 mm was used. The plate-like body is a stainless steel plate having a rectangular cross section, a height of 50 mm, a thickness of 0.3 mm, and a length of 200 mm that traverses in the width direction of the glass ribbon, as shown in FIG. Projecting toward the molten tin bath side. N ₂ as an inert gas was supplied to the contact portion between the glass ribbon and the removing member at 5 liters / minute using the space inside the square pipe. The through holes of the fixing member for supplying the inert gas were provided at equal intervals of 3 mm in diameter and 10 mm in the width direction of the glass ribbon. The removal member was fixed to the fixing member by applying a stainless steel plate to the left and right ends of the removal member.

As a result of the experiment, the defects and scratches of tin and tin oxide on the lower surface of the glass ribbon were not confirmed. About 0.1 piece / m ² of tin and tin oxide defects in the region when the removing device was not used was discovered. From this, the high effect by removal of tin and tin oxide on the lower surface of the glass ribbon of the removing apparatus according to the present invention could be verified. Further, the removal member was not worn or damaged, and there was no problem with durability.

Since the present invention can produce a high quality glass sheet by removing foreign matters such as molten tin adhering to the glass ribbon, it can be used for producing a glass sheet by a float process.

The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2006-331918 filed on Dec. 8, 2006 are cited here as disclosure of the specification of the present invention. Incorporated.

Claims (12)

  In a method for producing a glass sheet by a float process, a molten member drawn from a molten tin bath and in contact with a removal member made of a heat-resistant fiber sheet is brought into contact with the surface of the glass ribbon in the melting temperature range of the tin, and the melt adhered to the glass ribbon surface. A method for producing a glass sheet, characterized by sweeping and removing foreign matter such as tin.   The manufacturing method according to claim 1, wherein the removal member is in a non-oxidizing atmosphere.   The method for producing a glass sheet according to claim 1 or 2, wherein the heat-resistant fiber sheet is a felt-like sheet or a woven or non-woven sheet made of at least one selected from carbon fibers and silica fibers.   The manufacturing method of the glass sheet of Claim 1, 2 or 3 which urges | biases the said removal member to the surface of a glass ribbon with an elastic force or gas pressure.   The manufacturing method of the glass sheet in any one of Claims 1-4 which makes the said removal member contact the lower surface of a glass ribbon. A method of removing foreign substances such as molten tin drawn from a molten tin bath in the process of producing a glass sheet by a float process and adhering to the surface from the surface of the glass ribbon in the melting temperature range of the tin,
A method for removing foreign matter such as molten tin, wherein a removing member made of a heat-resistant fiber sheet is brought into contact with the surface of the glass ribbon and the foreign matter such as molten tin is swept away from the surface of the glass ribbon.   The method for removing foreign matter such as molten tin according to claim 6, wherein the removal member is in a non-oxidizing atmosphere. A removal device for removing foreign substances such as molten tin drawn from a molten tin bath in the process of producing a glass sheet by a float process and attached to the surface from the surface of a glass ribbon in the melting temperature range of the tin,
The removing device includes a removing member that comes into contact with the surface of the glass ribbon and wipes and removes foreign matters such as molten tin from the surface of the glass ribbon, and a fixing member that supports the removing member. A removing device characterized in that the removing member is formed of a heat-resistant fiber sheet.   The removal device according to claim 8, wherein the fixing member includes an elastic body that biases the removal member toward the surface of the glass ribbon.   The removal device according to claim 8, wherein the fixing member has a gas passage for biasing the removal member to the surface of the glass ribbon with a gas pressure.   11. The removing device according to claim 8, wherein the removing member has a mountain shape in a state where the removing member is supported by the fixing member, and a top portion of the mountain shape contacts the surface of the glass ribbon.   The removal apparatus according to any one of claims 8 to 11, wherein the heat-resistant fiber sheet is a felt-like sheet or a woven or non-woven sheet made of at least one selected from carbon fibers and silica fibers.

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