JPS6343325B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for strengthening plate glass by blowing a cooling medium onto the plate glass heated to a temperature equal to or higher than the strain point.

Conventionally, the method of strengthening plate glass by spraying a cooling medium onto plate glass heated to a temperature above the strain point involves pre-mixing air or water mist with air through multiple jets installed close to the plate glass. It is known to strengthen plate glass by spraying it with liquid or water mist directly.

However, in the method of strengthening plate glass by blowing air on it, when air is blown uniformly over the entire surface of the plate glass, the air blown on the central area of the plate glass is more difficult to leave the blown area than on the peripheral area of the plate glass. As a result, the time for which the air heat-exchanged with the heated sheet glass remains in the central region becomes longer, and the degree of reinforcement in the central region of the sheet glass tends to be lower than that in the peripheral region. In order to compensate for this drawback, if the air pressure in the central area of the glass plate is made higher than in the peripheral area, there is a problem in that the glass plate becomes distorted and deformed.

The method of strengthening by pre-mixing water mist and air and blowing it onto a heated plate glass is because the particle size of the water mist increases in the process of mixing the water mist and air (mixer) and becomes water droplets. The water contact with the glass plate causes damage to the glass plate, and the cooling of the glass plate becomes locally uneven, making it difficult to control.

In the method of directly spraying water mist onto heated plate glass to strengthen it, it is difficult to apply force to the water mist, so controls such as limiting the spraying position of the water mist and partially changing the cooling ability of the plate glass are necessary. was difficult.

In addition, when spraying water mist onto high-temperature plate glass to rapidly cool and strengthen it, the particle size of the water mist is usually 20~20~
A diameter of 80 μm is preferable, but at the initial stage of ejecting water mist from the water mist outlet,
Due to the low pressure at the tip of the nozzle, water mist or water droplets with a particle size of 100 μm or more were ejected, causing problems such as damage to the glass plate.

The present invention was made in order to eliminate the drawbacks of the conventional method as described above, and utilizes the difference in cooling ability between water mist and air by separately blowing air and water onto a plate glass. To provide a method for strengthening plate glass that makes it easy to make the degree of strengthening uniform over the entire surface of the plate glass or to partially change the degree of strengthening of the plate glass by controlling the position where mist contacts the plate glass, Moreover, water mist or water droplets with a large particle size are suppressed from being ejected from the water mist ejection port, thereby preventing damage to the glass plate.

That is, the sheet glass strengthening method of the present invention is a method of strengthening sheet glass by blowing a cooling medium onto sheet glass heated to a temperature equal to or higher than the strain point, in which the sheet glass is Water mist is sprayed onto the sheet glass from one or more water mist nozzles that blow air over the entire surface and have a set valve that opens when the pressure exceeds a set pressure and is provided between the air nozzles in the vicinity of the glass sheet. It is characterized by spraying.

FIGS. 1 and 2 show one embodiment of the present invention. A plate glass 2 whose end is suspended by a plate glass hanger 1 and heated in a heating furnace to a temperature higher than the strain point, for example 550 to 700°C.
is transferred into the quenching device 3, and is quenched and strengthened by being sprayed with a cooling medium. Rapid cooling device 3 is plate glass 2
It is provided with a plurality of air jetting pipes 4 extending in the horizontal direction in the vicinity of the glass plate 2 and a plurality of water mist generating nozzles 5 provided so as to be located in the central area of the plate glass 2. The air jet pipe 4 is provided with a plurality of holes or slits to form an air jet port 6, and the compressed air supplied to the pipe 4 is passed through the plate glass 2.
The entire surface of the glass plate 2 is rapidly cooled. The water mist generating nozzle 5 is supplied with, for example, pressurized water and sprays a water mist 7 in the form of a mist of liquid onto the glass plate 2 .

FIG. 3 shows one embodiment of the water mist generator according to the present invention. Water to be made into a mist is passed through a strainer 9 from a storage tank 8 to a rotary pump 10.
The water is pressurized and supplied to the header 12 via the water supply pipe, and the header 12 supplies the water to the plurality of water mist generating nozzles 5. Further, the water supply pipe 11 is provided with a pipe 13 for adjusting the ejection pressure.

The water mist outlet has an activation setting valve that opens at a setting pressure or higher. FIG. 4 shows an example of the configuration, in which when the pressure applied to the water mist generating nozzle 5 exceeds a set value, the check valve 14 opens and the water mist 7 is spouted.

Fig. 5 is a graph showing the relationship between the ejection time and the pressure applied to the water mist generating nozzle. In the graph, A is a case using a water mist generating nozzle without a check valve, and B is a case using a check valve. The check valve opens when the pressure exceeds the set pressure (point F). In A, water mist starts to eject from point E, and in area C
Water mist or water droplets with a particle size of 100 μm or more are generated, and water mist with a particle size of 100 μm or less is generated in the region D. At point B, by using a check valve or the like to open the activation setting valve only when the set pressure is exceeded, area C is eliminated and water mist is not ejected from point F, for example.
A water mist of 80μm or less is ejected.

The amount of water mist sprayed is preferably 20 to 400 ml/m ³ sec, less than 20 ml/m ² sce will not necessarily provide sufficient reinforcement, and exceeding 400 ml/m ² sec will result in too large a cooling capacity. This will cause damage to the glass plate.

Note that in the embodiments shown in FIGS. 1 and 2,
A case is shown in which the water mist outlet is disposed in the central area of the glass plate 2. In this way, the central region of the plate glass, which tends to be relatively insufficiently cooled by simply blowing compressed air onto the plate, can be cooled with water mist, so the entire surface of the plate glass can be strengthened almost uniformly. Further, by appropriately changing the location and number of water mist outlets, it is also possible to partially change the degree of reinforcement of the glass plate.

As is clear from the above, according to the present invention, air is blown over the entire surface of the glass by the air outlet provided close to the plate glass heated above the strain point, so that air is blown over the entire surface of the glass. The water mist ejected from one or more water mist outlets provided between them is attracted by the air jet force and is blown directly onto the plate glass, preventing the particle size of the water mist from increasing. can be used effectively, and breakage of the plate glass can be prevented. In addition, since the air nozzle and the water mist nozzle are independent, the position and number of the water mist nozzle can be adjusted appropriately by taking advantage of the difference in cooling ability between water mist and air. It has the remarkable effect that it is easy to uniformly strengthen the entire surface and to locally change the degree of reinforcement. Furthermore, when glass sheets heated to high temperatures are transferred to a quenching device and sprayed with water mist to rapidly cool and strengthen the glass, the generation of water mist and water droplets with a particle size of 100 μm or more at the initial stage of water mist ejection is suppressed. It is possible to prevent reinforcement failures due to breakage of the glass plate or unevenness in the degree of reinforcement.

Examples of the present invention are shown below.

Example 1 Heated to 650℃, size 500×500mm, thickness 3.3mm
Using the device shown in Figures 1 to 4, air is jetted from the air outlet at an air pressure of 4 kg/cm ² onto a glass plate, and at the same time, the water mist generated from the water mist generating nozzle is sprayed in an amount of 50 ml. /m ²・sec
and 100 ml/m ² ·sec was blown onto the central area of the plate glass to strengthen it by cooling. At this time, the interval between the air jetting pipes provided facing each other was set to 50 mm, and the check valve was opened to generate water mist when the water pressure applied to the water mist jetting port was 4 kg/cm ² .

These and comparative examples include air only (4Kg/cm ² )
The degree of strengthening was measured by spraying on plate glass and strengthening it by cooling. The degree of reinforcement was measured by the number of fractures (pieces/50 mm square) when the plate glass was crushed from the center, and the results are shown in Figure 6. In Figure 6, the curve is for air only, the curve is for adding water mist to the central region (50 ml/m ² sec), and the curve is for adding water mist to the central region (100 ml/m 2 sec).
m ² sec). The results show that the glass sheet is further strengthened by combining air and water mist according to the present invention.

Further, no water mist or water droplets with a diameter of 100 μm or more was observed, and no breakage of the glass plate occurred.

Example 2 The heating temperature and rapid cooling device for sheet glass are the same as in Example 1.
In the same manner as above, the plate glass was rapidly cooled and strengthened by varying the air pressure and water mist amount. The degree of reinforcement of plate glass was measured in the same manner as in Example 1, and the results were reported in Example 7.
As shown in the figure. In the figure, curve G is when the air pressure is 4Kg/ ^cm2 ,
Curve H shows the case where the air pressure is 5 kg/cm ² . From this result, it can be seen that when the amount of water mist is 20 ml/m ² ·sec or more, the plate glass is strengthened well.

[Brief explanation of drawings]

Figure 1 shows one of the quenching devices used to carry out the present invention.
It is a schematic side view which shows an example. FIG. 2 is a schematic front view of FIG. 1. FIG. 3 is a diagram showing one embodiment of the water mist generator. FIG. 4 is a partially cutaway sectional view showing a configuration example of a water mist spout having an operation setting valve that opens at a pressure equal to or higher than a set pressure. FIG. 5 is a graph showing the relationship between the ejection time and the pressure applied to the water mist generating nozzle. FIG. 6 is a graph showing the results of measuring the degree of reinforcement. FIG. 7 is a graph showing the relationship between the amount of water mist and the number of fractures. DESCRIPTION OF SYMBOLS 1... Plate glass hanger, 2... Plate glass, 3... Rapid cooling device, 4... Air jetting pipe, 5... Water mist generating nozzle, 6... Water mist spout, 7... Water mist, 8...
Storage tank, 12...Header, 14...Check valve.

Claims (1)

[Claims] 1. A method of strengthening plate glass by blowing a cooling medium onto a plate glass heated to a temperature equal to or higher than the strain point, in which air is blown over the entire surface of the plate glass from a plurality of air outlets provided close to the plate glass, and the Strengthening of plate glass characterized by spraying water mist onto the plate glass from one or more water mist outlets each having a set valve that opens at a pressure equal to or higher than a set pressure, which is provided between the air outlets adjacent to the plate glass. Method.