Method for bending and thermally prestressing radiation shielding glass

摘要

A method for bending radiation shielding glass which has a heavy metal oxide content of at least 50% by weight is provided, wherein first a mold is provided, a glass plate comprising a radiation shielding glass is then provided, the mold is preheated to a temperature of 300 to 400° C., the glass plate is placed on the mold, the glass plate and the mold are heated in a furnace to a temperature of 370 to 430° C., then heated together to a temperature of 400° C. to 500° C., preferably to 440 to 500° C., the total heating time being at least 30 minutes, preferably at least 60 minutes, the glass plate is then molded and finally the molded glass is cooled by means of a cooling program over a period of at least 60 minutes. For thermal prestressing, the glass body is supported at least at its outer periphery at a number of support points, introduced into a preheated furnace, heated to 400 to 500° C. and then removed, and cold air is blown onto both sides from a multiplicity of nozzles, preferably until cooling to about 100° C. has taken place.

主权项

1. A method for bending and thermally prestressing radiation shielding glass, comprising the following steps:
(a) providing a mold; (b) providing a glass plate comprising a radiation shielding glass; (c) preheating said mold to a temperature of 300 to 400° C.; (d) placing said glass plate on said mold; (e) heating said glass plate and said mold together to a temperature of 370 to 430° C.; (f) further heating to a temperature of 400° C. to 500° C., steps (e) and (f) together lasting for at least 30 minutes; (g) molding said glass plate into its final form; (h) cooling said glass plate after molding to a temperature of not more than 150° C. by means of a cooling program over a period of at least 60 minutes; (i) removing the glass body from the mold; and thereafter thermally prestressing the radiation shielding glass by: (j) supporting said glass body at a plurality of support points including at least at its outer periphery and at an intermediate point; (k) introducing said glass body into a furnace which has been preheated to a temperature of 500 to 600° C.; (l) heating said glass body to 400° C. to 500° C.; (m) removing said glass body from said furnace; and (n) blowing a cold fluid onto said glass body on both sides from a plurality of nozzles until said glass body has cooled to a surface temperature of not more than 150° C.