GB830733A - Improvements in or relating to hollow glass bodies - Google Patents

Abstract

830,733. Hollow glass ware. GLACES DE BOUSSOIS. July 25, 1958 [July 30, 1957], No. 24042/58. Class 56. Hollow glass ware, e.g. bottles, jars and beakers, of small wall thickness and high mechanical strength is made by a process which comprises bringing the walls of a hollow glass body having an orifice leading to the interior to a temperature at which the viscosity of the glass is below 109 poises, cooling the glass from the outside while maintaining the mean viscosity between 10<SP>9</SP> and 1012 poises, and blowing the walls with a gas whose temperature is at least equal to that of the internal surface of the glass and finally solidifying the walls by cooling from the outside. The hollow glass body is given its temporary form by the " press-and-blow " or " blow-and-blow " method. Any annealing is confined to the region near the orifice. Fig. 2 shows a jar 1, which has previously been heated by radiation in a chamber, surrounded by the mould 18 composed of a thick inner envelope 19 and a sheet-metal outer envelope 20 which is provided with passages 21 and 22 for admitting and discharging cooling gas supplied through nozzles 23 to act on the outside of the jar. The thermal conditioning is immediately followed by the admission of hot high-pressure gas to the interior of the jar by means of blowing-head 24 and duct 25. The rapid solidification of the glass may be effected by conduction of heat from the mould lining or by an arrangement (not shown in Fig. 2) whereby the expansion of the glass triggers off a fresh supply of cooling gas. In each case it is the outer layer which solidifies first, whereafter solidification progresses rapidly through the glass thickness to the inner layer. The inner surface of the mould should be of high reflecting power, e.g. stainless steel, gold, platinum, gold-platinum alloy or powdered titanium oxide.