A process for sejghærdning of glass, as well as apparatus for carrying out the method.

摘要

927,848. Tempering glass. TRIPLEX SAFETY GLASS CO. Ltd., J. R. BEATTIE, and K. J. B. WOLFE. April 20, 1961 [April 20, 1960], No. 13904/60. Class 56. A method of toughening at least part of a glass article, e.g. windscreen or insulator, comprises heating the article above the " relaxation temperature " (defined) and then exposing the heated glass article to the quenching action of a gaseous chilling medium characterized, by measuring energy radiated from the heated glass part being toughened and employing this measurement to control the delivery of the gaseous chilling medium used in the toughening process. The regulation of the gaseous chilling medium may be effected by a pyrometer which measures the temperature of the surface of the glass article. Alternatively two pyrometers may be used responsive to radiation emitted from the surface of the article and from the main body thereof. The pyrometer is rendered sensitive to radiation in the wavelength range 5-9Á by means of an optical lead selenide filter. A glass sheet 1 (Fig. 1) is positioned between quenching frames 2 approximately 3 inches from the surface of the sheet. A motor 3 (Fig. 2) drives pump 4 which pumps gaseous chilling medium, e.g. air, into tank 5 from which it flows through control valve 6 and via manifold 7 to frame 2. Mounted on sheet 1 is the optical pyrometer 8. The output of the pyrometer which depends on the temperature of glass surface layer is fed to control valve 6 which regulates the flow of air to the quenching frames. The valve 6 consists of a controller which is set to operate at a predetermined output voltage of the pyrometer. When two pyrometers are used they may be mounted together on or behind quenching frame 2, one measuring the surface temperature and the other measuring radiation from the whole body. They are connected to the controller through a change-over switch which enables one or both to operate. The two pyrometers may be used in opposition when it is desired to measure the temperature differential between the surface and the centre of the glass sheet. When only part of the glass article is to be toughened the other parts of the article are masked during the quenching process.