JPS59217629A - Apparatus for reinforcing glass plate - Google Patents

Abstract

PURPOSE:To prevent the nonuniformity of the contact pressure of a cooling plate to a glass plate caused by the warpage of the cooling plate, by sandwiching a heated glass plate wth a pair of cooling plates wherein the contacting face is covered with a carbon fiber cloth, and quenching the glass plate. CONSTITUTION:A hot glass plate is sandwiched between a pair of cooling plates, and quenched to effect the solid-contact reinforcement of the glass plate. In the above process, the surface of each cooling plate contacting with the glass plate is covered with a cloth made of carbon fibers. A cushioning material inserted between the cooling plate and the glass plate is preferably the one having the highest possible thermal conductivity and capable of keeping the cooling efficiency even if the material is thick, i.e. having high thermal conductivity, low expansion coefficient, and excellent elasticity when formed to a cloth (including sheet). A carbon fiber cloth (woven cloth, nonwoven cloth, etc.) best satisfies the above requirements for the cushioning material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for solid-state contact strengthening of a glass plate by heating a glass plate and then quickly cooling the glass plate by sandwiching the glass plate between cooling plates. This relates to a cushioning material that is coated on the side.

The glass plate is heated and the heated glass plate is rapidly cooled.
A physical strengthening method in which residual stress is generated in the temporary thickness direction of the glass 2 at room temperature to form a compressive stress layer on the surface layer is widely practiced.

Among these, enhanced wind cooling, which uses air jets for cooling, is the most widely used.

Physical strengthening methods are classified into the above-mentioned air cooling method, immersion cooling method in which the material is immersed in a liquid, and the solid contact method which is the object of the present invention. . As mentioned above, the air-cooling method is the most widely used method, but it requires a lot of power from the blower to increase the cooling capacity, and in order to prevent the support part of the glass plate from deforming, the air-cooling method is There are problems such as the need to prevent the glass plate from vibrating during cooling. Although the immersion method can increase the cooling rate, it tends to cause uneven cooling due to thermal convection, evaporation, etc. of the liquid during immersion cooling, and there are problems such as damage to the glass plate.

The solid contact method involves heating a glass plate above the strain point temperature or close to the softening temperature, then sandwiching it between cooling plates and applying appropriate contact pressure.
This is a method of rapidly cooling and strengthening by heat conduction between the cooling plate and the glass plate. Generally, a refrigerant such as water is passed through the cooling plate as necessary to cool the cold comb 11.

In the solid contact method, the strengthening of the glass plate depends on the cooling capacity of the cooling plate. Because it is necessary for the pressure to be uniform, the surface of part d) is precisely machined.
It is a flat surface with as few irregularities as possible.However, because there are some unevenness left on the surface of the cooling plate, if the glass plate is directly suppressed by the cooling plate, In order to prevent damage to the glass plate and uneven film on the cooling plate, and to adjust the cooling rate,
[For example, if the cooling power is too strong, there is a risk of breaking the glass plate, so adjust the cooling rate. ) The surface of the cooling plate is covered with glass fiber, metal fiber, etc. cloth.

Therefore, the glass plate is cooled via the buffer material and the cooling plate.
Overall heat transfer coefficient II (kcal/n? l
+°C) is as shown in equation (1) 1°he: 9p Heat transfer coefficient of surgical department (kca J / ni' h ”C)
[1P: Cooling (Anti II (II) d:
Thickness of cooling plate (m) λ: Heat transfer coefficient of cooling plate (kcaJ / rd h 0
C) For example, on a cooling plate of 30rnm thick copper plate, 0.2
0.5 kg when covered with a mm-thick glass fiber cloth cushioning material
/cn? When the glass plate is cooled with a contact pressure of
It becomes rr hoC.

The heat transfer coefficient of the glass fiber cloth is approximately 0.04
kcal/ rrr h ℃), thickness 0.2m+n)
Based on the contact pressure (0.5 kg/c1t?), it is determined to be 400 kcal/+n h 'C from the experimental results. Increasing the contact pressure also increases the heat transfer coefficient. In this way, the cooling capacity depends on the cushioning material, but is approximately 400kca]
, / rrr h 'The value of the overall heat transfer coefficient of C is 3 mm
This corresponds to the cooling capacity required to strengthen the cooling of thick glass plates.

There are the following problems here. That is, when the glass plate is strengthened by cooling, the side of the cooling material that comes into contact with the glass plate is heated and the other side is cooled, creating a humidity difference, which causes warping.

Cooling If warpage occurs, it becomes impossible for the cooling plate to contact the glass plate with uniform pressure. To this end, it is necessary to prevent the cooling plate from warping 7 and, if this is unavoidable, to thicken the cushioning material 7 to absorb the warp.

The object of the present invention is to provide a glass plate that eliminates uneven contact pressure between the cooling plate and the glass plate due to warpage of the cooling plate due to temperature differences, and that can cool and strengthen the glass plate with sufficient cooling capacity. to provide reinforcement equipment.

A glass plate strengthening device according to the present invention is an apparatus for solid contact strengthening of a glass plate by heating a glass plate, then sandwiching it between cooling plates, and then rapidly cooling the glass plate, in which the side that sandwiches the temporarily cooled glass plate is made of carbon fiber This device is characterized by being covered with cloth.

The cushioning material has the so-called cushioning ability of absorbing irregularities on the surface of the cooling plate and the function of preventing too rapid cooling that can cause damage to the glass plate, and also forms a bottleneck in the cooling path, which is important for strengthening the glass plate. Therefore, it must have the required heat transfer ability (cooling ability). If the cushioning material is made thicker in order to increase the cushioning ability, the cooling ability may be reduced and it may become useless. Therefore, it is desirable that the cushioning material be long enough to maintain thermal conductivity, and that even if it is thick, the cooling capacity will not decrease much. In addition, the thicker the cushioning material, the greater the expansion due to the heat received from the glass plate, so it swells when it is sandwiched between the glass plate and the cooling plate, making the surface uneven and creating the pattern of the cushioning material on the glass plate. It ends up. Therefore, it is necessary to have a high thermal conductivity and a low coefficient of expansion.

As a cushioning material, it is necessary to have high thermal conductivity, low coefficient of expansion, and excellent elasticity when used as cloth (including cloth), but the present inventors have conducted various research. As a result of repeated research, it was discovered that woven fabrics, non-woven fabrics, and other fabrics made of carbon fiber best satisfy the above characteristics as a cushioning material, and the present invention was completed. Table 1 shows the characteristic values of various fibers.

The coefficient of linear expansion indicates the value of the material. 400kcal/nr
The thickness of the heat transfer coefficient h'C is calculated by setting the contact pressure to 0.5I\! as in the case of calculating the equation (2) above. ζ8, 11
? When pressed, 1I00kcal/nr h
'C heat (B is the thickness of the buffer material showing the lff1 coefficient.

Example 30 A copper plate with a thickness of +11111 is covered with a carbon fiber cloth with a thickness of 0.51 tg/cut (7)
3 bleached thickness with pressure (7) 300 x 300 nun c
7) Glass plates of the same size were sandwiched and strengthened by cooling. As a result, the copper plate had a warpage of 0,]3+, but the glass plate was strengthened uniformly over the entire surface, and there was no distortion on the surface of the glass plate.

? Comparative Example Example I, Onun thick charcoal 7j3 iAU
The glass plate was cooled and strengthened in the same manner as in the example except that glass fiber (h'& T), 2 nm+ thick was used. As a result, the copper plate was 0.13m as in the example.
A warp of m occurred, and the glass plate was only strengthened in the center.

As described above, when using the apparatus of the present invention, even if the cooling plate warps, the buffer material absorbs it, and the cooling plate can sandwich and cool the glass plate with uniform contact pressure. Excellent tempered glass can be obtained since it can be cooled at a speed sufficient to strengthen the glass plate.

Applicant: Asahi Glass Co., Ltd.

Claims (1)

[Claims] In an apparatus for solid contact strengthening of a glass plate by heating a glass plate and then rapidly cooling the glass plate by sandwiching the glass plate between openings, the side of the cooling plate that sandwiches the glass plate is covered with a cloth made of carbon fiber. Characteristic glass plate strengthening device.