| 摘要 |
1,263,286. Tempering glass. VETRERIA MILANESE LUCCHINI PEREGO S.p.A. 21 April, 1969 [20 April, 1968], No. 20244/69. Heading C1M. Glass pieces having at least two plane sides 11 joined along an edge by a curved portion so that the plane surfaces are at an angle, e.g. a U- shaped channel piece, are tempered, after formation and cutting of the piece, by rapidly cooling the glass with a cooling medium, preferably gaseous (e.g. air), such that the highest cooling rate is at the concave (i.e. interior) surface of the angle 10, the lowest at the convex (exterior) surface, and the plane surfaces are cooled at an intermediate rate, so that the heat dissipation is uniform, giving a uniform stress distribution. A channel shaped piece may be tempered in the apparatus shown which comprises two sets of chambers 20, 21, each chamber being supplied with gas via header tubes 32, 33, and the gas being emitted through slots 26, 27 and 29. Slots 26 and 27 are narrower than slots 29: thus a higher cooling rate is maintained at the concave (interior) surface of the angle. A similar device, in which the slot width is narrower at the corners, is used as the complementary part 20 (Fig. 7, not shown). Glass pieces may be tempered by this method whose radius of curvature at the inside of the angle is less than the thickness of the glass. |
