JP2001213631A - Apparatus for manufacturing tempered glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus to manufacture tempered glass having higher toughness than the conventional tempered glass at the high efficiency production rate. SOLUTION: This apparatus comprises a roller conveyer 12 to convey the sheet glass 11, a heating oven 18 disposed in the course of this roller conveyer 12 and heating the sheet glass 11 in conveyance to the specified temperature, a heating means 20 disposed after the outlet of this heating oven 18 and heating the sheet glass 11 in conveyance from the bottom side 11a, and a cooling unit 25 disposed after the outlet of this heating means 20 and cooling the sheet glass 11 in conveyance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tempered glass manufacturing apparatus used as, for example, fire protection glass for buildings.

[0002]

2. Description of the Related Art Tempered glass in which the degree of strengthening of a sheet glass is increased by forming a compressive stress layer on the surface of the sheet glass is known. Since tempered glass can also adapt to sudden changes in temperature, it is used for applications such as fire prevention glass for buildings. By the way, for some applications, tempered glass having a higher degree of tempering than ordinary tempered glass (hereinafter referred to as “high-strength tempered glass”) is desired. The technique for producing this high-strength tempered glass will be described below.

FIG. 3 is a side view showing a conventional tempered glass manufacturing apparatus, and shows one method of manufacturing high-strength tempered glass using this apparatus. First, the sheet glass 100 is heated to a predetermined temperature in the heating furnace 101. The predetermined temperature is set higher than in the case of manufacturing normal tempered glass in order to increase the cooling start temperature of the glass sheet 100.

[0004] Next, the heated sheet glass 100 is carried out from an outlet 101a of a heating furnace 101 by conveying rollers 102 (... indicates a plurality of sheets; the same applies hereinafter). Next, cooling air is blown from both nozzles 104... To both surfaces (upper and lower surfaces) of the glass sheet 100 as shown by arrows, thereby rapidly cooling the glass sheet 100 from the cooling start temperature. Thereby, a high-strength tempered glass having a higher tempering degree than ordinary tempered glass is obtained.

[0005]

However, if the set temperature of the heating furnace is set higher than in the case of manufacturing a normal tempered glass, the sheet glass 100 becomes too soft in the heating furnace. If the glass sheet 100 becomes too soft, if glass powder or a small piece of furnace material is sandwiched between the glass sheet 100 and the conveying rolls 102..., The glass sheet will be scratched or dented.

As techniques for preventing the occurrence of scratches and dents in tempered glass, for example, Japanese Patent Application Laid-Open No. 53-149206, entitled "Roll for Rolling Glass Plate" and Japanese Utility Model Application Laid-Open No. 1-106533, entitled "Horizontal Heating Furnace for Forming Sheet Glass""It has been known.
The technology disclosed in Japanese Patent Application Laid-Open No. 53-149206 is intended to prevent the occurrence of scratches or dents in the sheet glass by flattening the surface of a transport roll. However, even when the transport roll is flat, if glass powder or small pieces of furnace material enter between the transport roll and the plate glass, the plate glass will be damaged or dent. If scratches or dents occur in the sheet glass, the product is defective and is discarded, which is a factor that makes it difficult to increase the productivity of tempered glass.

The technique disclosed in Japanese Utility Model Laid-Open Publication No. 1-106533 is
By coating the carrier roller with a silica sleeve and absorbing the glass powder and small pieces of furnace material that have entered between the carrier roller and the plate glass, the scratches and dents on the plate glass are suppressed by absorbing the mesh of the silica sleeve. is there. However, this technology needs to be replaced from time to time because the silica sleeve comes into contact with the edge of the float glass and needs to be replaced from time to time, and it takes time to replace the silica sleeve, which is a factor that makes it difficult to increase the productivity of tempered glass. Has become.

Therefore, an object of the present invention is to provide a technique capable of efficiently producing a high-strength tempered glass having a higher degree of tempering than ordinary tempered glass.

[0009]

According to one aspect of the present invention, there is provided a conveying roller for conveying a sheet glass, and a heating furnace disposed in the middle of the conveying roller for heating the sheet glass being conveyed to a predetermined temperature. And heating means arranged on the outlet side of the heating furnace to heat the sheet glass being conveyed from below, and a cooling device arranged on the outlet side of the heating means to cool the sheet glass being conveyed.

After the sheet glass is heated to a predetermined temperature in a heating furnace, the sheet glass is further heated by heating means outside the heating furnace. By heating the sheet glass in a heating furnace and a heating means in two stages, the heating temperature in the heating furnace is lowered to prevent the sheet glass from becoming too soft. For this reason, even if small pieces of glass powder or furnace material enter between the transport roller and the sheet glass, no scratches or dents occur in the sheet glass.

By the way, the transport rollers outside the heating furnace are:
Generally, a roller with a sleeve is used because the sleeve that covers the roller body can be easily replaced. For this reason, small pieces of glass powder that have entered between the transport roller and the plate glass are absorbed by the stitches of the sleeve. Therefore, even if the sheet glass is heated outside the heating furnace, no scratch or dent is generated in the sheet glass.

Further, the lower surface of the sheet glass is efficiently heated by heating the sheet glass from the lower surface side by the heating means. For this reason, even if the lower surface of the sheet glass contacts the transport roll, the temperature of the lower surface is kept relatively high. Therefore, it is possible to prevent the occurrence of cracks from the lower surface of the glass sheet when cooling the glass sheet.

According to a second aspect of the present invention, the heating means has a heating surface for heating the lower surface side of the sheet glass, and the heating surface is formed flat. By forming the heating surface of the heating means flat, the entire heating surface can be evenly brought close to the sheet glass. For this reason, the heat of the entire heating surface is efficiently transmitted to the sheet glass, and the heating time of the heating means is shortened.

According to a third aspect of the present invention, the cooling device comprises a plurality of air nozzles arranged along the sheet glass conveying direction, and among these nozzles, the inlet nozzle is a slit nozzle having a slit extending in the width direction of the sheet glass. It is characterized by having done.

Since the slit nozzle is arranged at the inlet of the cooling device, air is blown from the slit nozzle to form an air curtain. The air curtain separates the cooling device from the heating device, thereby preventing the air blown out from the air nozzle of the cooling device from flowing to the heating device side.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. FIG. 1 is a side view of a tempered glass manufacturing apparatus according to the present invention. The tempered glass manufacturing apparatus 10
1 and a heating furnace 18 arranged on the way of the conveying roller 12 to heat the glass sheet 11 being conveyed to a predetermined temperature, and a heating glass 18 arranged on the exit side of the heating furnace 18 and The heating means 20 includes a heating means 20 for heating the sheet glass 11 from the lower surface 11a side, and a cooling device 25 arranged on the exit side of the heating means 20 for cooling the sheet glass 11 being conveyed.

The plate glass 11 has a thickness of, for example, 6 to 10 m.
m, which becomes a high-strength tempered glass by quenching after heating. This high-strength tempered glass is used as, for example, fire protection glass for buildings.

The transport roller 12 includes a plurality of rollers 13... Horizontally arranged at a fixed interval in the heating furnace, and a plurality of coating rollers 16. .. a roller 13... And a covering roller 16
Are rotated by driving means (not shown) to convey the sheet glass 11 in the direction of the outline arrow A. .

The covering roller 16 comprises a roller body 17a connected to the driving means, and a sleeve 17b covering the outer periphery of the roller body 17a. By covering the roller body 17a with the sleeve 17b, even if a small piece of glass powder enters between the covering roller 16... And the plate glass 11, the small piece can be released into the mesh of the sleeve 17b.
For this reason, it is possible to prevent the small pieces from hitting the plate glass 11.

The heating furnace 18 heats the sheet glass 11 being conveyed by the rollers 13 to a predetermined temperature (for example, about 650 ° C.) near the exit of the heating furnace 18. The heating means 20 further heats the sheet glass 11 discharged from the heating furnace 18, and the main body 21 disposed between the coating rollers 16, and the lower surface 11 a side of the sheet glass 11 by being attached to the upper part of the main body 21. And a heating surface 22 for heating.

By disposing the heating means 20 on the outlet side of the heating furnace 18, the sheet glass 11 can be heated in the heating furnace 18 and then heated in two steps by the heating means 20. For this reason, the heating temperature in the heating furnace 18 can be lowered to prevent the sheet glass 11 from becoming too soft in the heating furnace 18.

Further, since the heating means 20 is provided on the outlet side of the heating furnace 18 (ie, outside the heating furnace 18), the heating means 20 can be arranged at a place where there is no need to worry about small pieces of the furnace material. . In addition, since the sheet glass 11 is heated at the location where the covering roller 16 is provided,
, And a small piece of glass powder enters between the sheet glass 11 and the small piece can escape into the mesh of the sleeve 17b. For this reason, it is possible to prevent the small pieces from hitting the plate glass 11.

Further, the sheet glass 11 can be heated to a desired temperature by the heating means 20. Therefore, a sufficient cooling capacity can be secured, and a tempered glass having a higher tempering degree than ordinary tempered glass can be obtained. Also,
By increasing the heating temperature of the glass sheet 11, it is possible to prevent the glass sheet 11 from cracking when the glass sheet 11 is rapidly cooled.

The cooling capacity expresses the degree to which the glass heated to near the softening point is deprived of heat by the cooling air, and is expressed by the heat transfer coefficient. That is, when the cooling capacity is large, the glass is rapidly cooled, and a high compressive stress can be formed on the glass surface.

Here, the reason why the heating means 20 is arranged below the plate glass 11 will be described. Generally, when the glass sheet 11 is transported by the coating roller 16, the lower surface 11 a of the glass sheet 11 comes into contact with the coating roller 16, and the temperature tends to decrease.
For this reason, a crack is easily generated from the lower surface 11a of the sheet glass 11 when the sheet glass 11 is cooled. Therefore, heating means 2
By disposing the 0 heating surface 22 so as to face the lower surface 11a of the glass sheet 11, the lower surface 11a of the glass sheet 11 is efficiently heated and the temperature of the lower surface 11a is maintained relatively high.

Hereinafter, the heating means 20 will be described in detail. The heating means 20 spreads a metal fiber mat flatly on a gas combustion surface (hereinafter, referred to as a “heating surface”) 22,
The flat heating surface 22 is connected to the lower surface 1 of the glass sheet 11.
This is a gas burner (plane burner) arranged to face 1a and burn gas on a flat heating surface 22.

The heating means 20 sets the width W of the flat heating surface 22 to at least 100 mm,
Is set to 10 mm at a distance L that is separated downward from the plate glass 11, and in this state, the gas is burned to heat the surface of the heating surface 22 so as to exceed 1000 ° C.

By forming the heating surface 22 flat, the entire area of the heating surface 22 can be made even closer to the sheet glass 11. Therefore, heat of the entire heating surface 22 can be efficiently transmitted to the glass sheet 11. In addition, by arranging the heating surface 22 at a position (10 mm) close to the lower surface 11a of the glass sheet 11 and setting the surface temperature of the heating surface 22 to a high temperature exceeding 1000 ° C., the efficiency of the glass sheet 11 in a short time is improved. Can be heated well.

Therefore, even if the heating time in the heating means 20 is shortened, the sheet glass 11 can be reliably heated to a desired temperature. Therefore, the heating area of the heating means 20 can be set short. Even if the glass sheet 11 is heated to a high temperature, the glass sheet 11 is conveyed by the coating roller 16 whose surface is covered with the sleeve 17b. Even if it enters, the small pieces can escape into the mesh of the sleeve 17b. Therefore, no scratches or dents occur in the sheet glass 11.

The cooling device 25 is provided with upper and lower slit nozzles 26 at the inlet of the cooling device 25.
6 are provided on the downstream side of 6. The slit nozzle 26 has a slit extending in the width direction of the glass sheet 11, and forms an air curtain by blowing air. The air nozzle 28 is arranged along the transport direction of the glass sheet 11, and cools the glass sheet by applying air blown from the nozzles to both sides of the glass sheet 11.

A slit nozzle 26 is provided at the inlet of the cooling device 25.
Are arranged, and an air curtain can be formed by blowing air from the slit nozzles 26. Since this air curtain can separate the cooling device 25 from the heating means 20, the air nozzle 28 of the cooling device 25
Can be prevented from flowing out to the heating means 20 side.

Next, the operation of the tempered glass manufacturing apparatus 10 will be described. 2 (a) to 2 (c) are operation explanatory diagrams of the tempered glass manufacturing apparatus according to the present invention. In (a), the atmosphere of the heating furnace 18 is set to 650 ° C., and the heating surface 22 of the heating means 20 is set to 1000 ° C. In this state, the transport roller 12 (that is, the roller 13... And the coating roller 16.
..) to drive the sheet glass 11 into the heating furnace 18.
To the inside of the The loaded plate glass 11 (shown by //) is transported by the rollers 13 of the heating furnace 18 as shown by the arrows. The glass sheet 11 is heated to approximately 650 ° C. by transporting the glass sheet 11 to the vicinity of the exit of the heating furnace 18.

By setting the heating temperature of the glass sheet 11 at a relatively low temperature of about 650 ° C., it is possible to prevent the glass sheet 11 from becoming too soft inside the heating furnace 18. For this reason, during conveyance of the sheet glass 11 inside the heating furnace 18,
Even if small pieces of glass powder or furnace material enter between the rollers 13... And the sheet glass 11, the sheet glass 11 is less likely to be scratched or dented.

Further, unlike the prior art, there is no need to attach a sleeve to the rollers in the heating furnace 18, so there is no need to perform a relatively difficult operation of replacing the sleeve in the heating furnace 18. Therefore, high-strength tempered glass can be efficiently produced.

In (b), the sheet glass 11 is placed in the heating furnace 1.
Leave the furnace from 8. The sheet glass 11 is transported by a transport roller 12
By being conveyed downstream by the (coating rollers 16, 16), the sheet glass 11 passes above the heating means 20 as shown by the arrow. Therefore, the lower surface 11a side of the sheet glass 11 is heated by the heating surface 22 of the heating means 20. Heating surface 22 is 100
Because it is set to a high temperature of 0 ° C, 650 ° C sheet glass 1
Heat 1 to 660 ° C.

The heating surface 22 is formed flat and the heating surface 2
2 is brought closer to the lower surface 11a of the glass sheet 11, and in this state,
Since the heating surface 22 is set at a high temperature of 1000 ° C., the heating time in the heating means 20 can be shortened. here,
Even if the glass sheet 11 is heated to a high temperature, the surface of the
7b, the sheet glass 11 is conveyed by the covering roller 16 so that even if a small piece of glass powder enters between the covering roller 16.
It can escape into the mesh of b. For this reason, it is possible to prevent the small pieces from hitting the glass sheet 11 and to prevent the surface of the glass sheet 11 from being scratched or dented.

In (c), the sheet glass 11 carried out of the heating means 20 is carried into the cooling device 25 by the coating rollers 16 as shown by arrows. At this time, the glass sheet 11 passes through the slit nozzles 26. Slit nozzle 26
Is formed by extending a slit in the width direction of the sheet glass 11, and forms an air curtain by injecting air from a slit nozzle 26. Therefore, it is possible to prevent the heat of the heating means 20 from entering the inside of the cooling device 25 by the air curtain, and to prevent the air injected from the air nozzles 28 of the cooling device 25 from flowing to the heating means 20 side. it can.

The sheet glass 11 that has passed through the air curtain of the slit nozzle 26 is conveyed to the air nozzles 28 by the coating rollers 16. The sheet glass 11 is cooled by blowing air from the air nozzles 28 to both sides of the sheet glass 11. In this way, a high-strength tempered glass in which the tempered degree of the flat glass 11 is increased by rapidly cooling the flat glass 11 compared to the normal tempered glass is obtained.

[0039]

EXAMPLES Examples of the present invention, Comparative Examples 1 and 2 will be described below with reference to Table 1. In the table, the fraction indicates the total number of samples in the denominator, and the numerator indicates the number of defective products (those having scratches, dents or cracks). Since a sensory test was performed on the scratches and dents, a limited sample was set, and the pass / fail was determined by comparing with the limited sample. Defective rate is 1
If it was 0% or less, the evaluation was ○ (pass). Regarding the occurrence of cracks, the case where the number of defective products was zero (0) was evaluated as ○. Otherwise, it is judged as x (fail).

[0040]

[Table 1]

Comparative Example 1 Ten samples having a thickness of 8 mm (float plate glass) were prepared, these samples were heated to 660 ° C. in a heating furnace, and then cooled by a cooling device to produce a high-strength tempered glass. . As a result, 6 out of 10 high-strength tempered glasses had scratches or dents, and 0 out of 10 had cracks. Therefore, the number of defective products with respect to scratches and dents is 10% or more, and the evaluation is x. In addition, the temperature of the lower surface side of the plate glass was measured in the non-contact state during the movement of the plate glass by measuring the temperature of the plate glass by using a radiation thermometer.

Comparative Example 2 Ten samples having a thickness of 8 mm (float plate glass) were prepared, and these samples were heated to 650 ° C. in a heating furnace and then cooled by a cooling device to produce a high-strength tempered glass. . As a result, 0 out of 10 high-strength tempered glass had scratches / dents,
Two out of 10 cracks occurred. Therefore,
Since the number of defective products is 10% or more with respect to cracks, the evaluation is x.

That is, the heating temperature in the heating furnace is 660 ° C.
When the temperature is lowered by 10 ° C., generation of scratches and dents can be prevented. However, it can be seen that cracks occur when the heated plate glass is cooled. For this reason, it turned out that even if the heating temperature of a heating furnace is lowered, high strength tempered glass cannot be efficiently produced.

Example: Ten samples (float plate glass) having a thickness of 8 mm were prepared, and these samples were heated to 650 ° C. in a heating furnace, and then heated to 660 ° C. by heating means. Next, the sheet glass heated to 660 ° C. was cooled by a cooling device to produce a high-strength tempered glass. As a result, scratches or dents in the high-strength tempered glass
The number was 0 out of 0, and the number of cracks was 0 out of 10. Accordingly, the number of defective products with respect to scratches, dents and cracks is less than 10%, and the evaluation is ○.

That is, according to the embodiment, the generation of scratches and dents is prevented by lowering the heating temperature in the heating furnace from 660 ° C. to 10 ° C., and the generation of cracks is prevented by heating to 660 ° C. by the heating means. I knew I could do it. Ten out of ten high-strength tempered glasses obtained in the examples could secure a higher degree of tempering than normal tempered glass.

In the above embodiment, the sheet glass 11
Has been described using float glass as an example, but the same effect can be obtained by using other plate glass such as polished plate glass or template glass. The thickness of the glass sheet 11 is set to 6
Although an example in which the thickness is set to 10 to 10 mm has been described, the present invention can be applied to a plate having a thickness other than 6 to 10 mm. Further, an example has been described in which the heating means 20 is a gas burner, but a heating means such as an electric heater or an infrared lamp may be used instead of the gas burner. In short, any material having a high energy density that can heat the glass sheet being transported in a short time may be used.

In the above embodiment, the heating means 20
Sets the width W of the heating surface 22 to 100 mm,
Is placed at a distance of 10 mm from the plate glass 11 and the heating surface 22
Although the example which heated so that it exceeded 1000 degreeC was demonstrated,
These values can be arbitrarily changed according to the thickness of the glass sheet 11.

Further, in the above embodiment, the heating furnace 18
The heating temperature of the plate glass 11 at 650 ° C. and the heating temperature of the plate glass 11 at the heating means 20 at 660 ° C.
These heating temperatures can be set arbitrarily according to, for example, the cooling capacity of the cooling device 25 and the thickness of the glass sheet 11.

[0049]

According to the present invention, the following effects are exhibited by the above configuration. According to the first aspect, the plate glass can be heated in two stages by the heating furnace and the heating means by disposing the heating means on the outlet side of the heating furnace. For this reason, the heating temperature in the heating furnace can be reduced so that the glass sheet does not become too soft in the heating furnace. Therefore, even if small pieces of glass powder or furnace material enter between the transport roller and the sheet glass, it is possible to prevent the sheet glass from being damaged or dented.

In addition, outside the heating furnace, the sheet glass is transported by the covering roller whose surface is covered with the sleeve, so that small pieces of glass powder that have entered between the transport roller and the sheet glass are absorbed by the stitches of the sleeve. Therefore, even if the sheet glass is heated outside the heating furnace, it is possible to prevent the sheet glass from being damaged or dented.

Further, by heating the sheet glass from the lower surface side by the heating means, the lower surface of the sheet glass can be efficiently heated. For this reason, even if the lower surface of the sheet glass comes into contact with the transport roll, a relatively high temperature of the lower surface can be ensured. Therefore, it is possible to prevent cracks from being generated from the lower surface of the glass sheet when cooling the glass sheet. As a result, a high-quality tempered glass of good quality can be stably obtained, so that the productivity of the high-strength tempered glass can be increased and the cost can be suppressed.

According to a second aspect of the present invention, by forming the heating surface of the heating means to be flat, the entire heating surface can be made evenly closer to the sheet glass. For this reason, the heat of the entire heating surface can be efficiently transmitted to the plate glass. As a result, a high-quality tempered glass of good quality can be stably obtained, so that the productivity of the high-strength tempered glass can be increased and the cost can be suppressed.

According to the third aspect, since the slit nozzle is disposed at the entrance of the cooling device, an air curtain can be formed by blowing air from the slit nozzle. Since the air curtain can partition the cooling device from the heating means, it is possible to prevent the air blown out from the air nozzle of the cooling device from flowing to the heating means. As a result, the productivity of the high-strength tempered glass having a high surface compressive stress can be increased, and the cost can be suppressed.

[Brief description of the drawings]

FIG. 1 is a side view of a tempered glass manufacturing apparatus according to the present invention.

FIG. 2 is a diagram illustrating the operation of the tempered glass manufacturing apparatus according to the present invention.

FIG. 3 is a side view showing a conventional tempered glass manufacturing apparatus.

[Explanation of symbols]

10 ... tempered glass manufacturing equipment, 11 ... sheet glass, 12 ...
・ Conveying rollers, 18: heating furnace, 20: heating means, 22
..Heating surface, 25 ... Cooling device, 26 ... Slit nozzle,
27 ... Air nozzle.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shigeki Obana 3-5-11 Doshomachi, Chuo-ku, Osaka-shi, Osaka F-term in Nippon Sheet Glass Co., Ltd. (reference) 4G015 CA02 CA05 CA08 CB01 CC01

Claims (3)

[Claims] 1. A transport roller for transporting a sheet glass, a heating furnace arranged in the middle of the transport roller to heat the sheet glass being transported to a predetermined temperature, and a sheet glass being transported disposed on the exit side of the heating furnace. And a cooling device disposed on the outlet side of the heating device to cool the sheet glass being conveyed. 2. The tempered glass manufacturing apparatus according to claim 1, wherein said heating means has a heating surface for heating a lower surface side of the sheet glass, and the heating surface is formed flat. 3. The cooling device comprises a plurality of air nozzles arranged along a conveying direction of the sheet glass, and among these nozzles, an inlet nozzle is a slit nozzle having a slit extending in a width direction of the sheet glass. The tempered glass manufacturing apparatus according to claim 1, wherein: