PROCESS FOR CRYOGENICALLY QUENCHING GLASS SHEETS

摘要

A process for quenching a heated glass sheet includes a pair of quench units (28) between which the glass sheet is located with each quench unit having nozzles (34) for directing cryogenic flows (36) including a liquid toward the oppositely facing surfaces (38) of the glass sheet so that the liquid completely vaporizes before penetrating the gas boundary layer on each surface of the glass sheet. The cryogenic flows (36) can be initially completely liquid or can be a two phase as the liquid and a gas with the latter preferably being done by spraying the two phase cryogenic flows as liquid droplets and the gas. The modulated cryogenic flows (36) can be started and fully stopped to provide flow pulses and can also be continuous and have periodically increased flow pulses. The cryogenic flows (36) can be interspersed with pressurized air flows (66) so as to cooperate with each other in providing the quenching. In one practice the interspersed cryogenic flows (36) and the pressurized air flows (66) can be provided at the same time as each other or at different times.