GB450464A - Improved method of and apparatus for tempering glass articles - Google Patents

Abstract

450,464. Tempering glass. PILKING- TON BROS., Ltd., 703, Tower Building, Water Street, Liverpool, and MITFORD, J. B., 425, Prescot Road, St. Helens, Lancashire. Jan. 17, 1935, No. 1573. [Class 56] In a method of tempering articles of non- uniform thickness by means of jets of a cooling medium such as air or steam, the thinner portions are subjected to a lower average rate of cooling than the thicker portions (other than projecting thick portions). This may be done by arranging that a smaller amount of cooling medium per unit of time and of area reaches the thinner than the thicker portions throughout the cooling operation or by delaying the start of cooling of the thinner portions. In the arrangements shown, the article 1 is rotated between frames formed by pipes 7 carrying the cooling fluid and furnished with jets. Alternatively the frames may be rotated and the article remain stationary. Where the article is not symmetrical about a central axis, the relative motion may be oscillatory instead of rotary. In the arrangements shown in Figs. 3 and 5, the proper rates of cooling are secured by the number and arrangement of the jets in the cooling frames. The article 1 in Fig. 5 has thick projecting portions 18, 25 which are cooled less rapidly than the rest of the article with the help of wire gauze or the like 20 and a suitable spacing of holes in the cooling frame. In the arrangement shown in Fig. 4, the supply of fluid to different parts of the cooling frame is separately controlled as by the valves 16, 17 so that cooling of the thin central and thinner portions of the article can be delayed.