METHOD OF AND APPARATUS FOR EVACUATING A GLASS CHAMBER

摘要

A method of and apparatus for evacuating a chamber (15), for example in vacu um glazing, that is enclosed in part by a glass wall (12) that includes an evacuation port (18). An evacuating head (10) is employed anal is arranged to cover the port (18) and a portion of the glass wall (12) that surrounds the port. The evacuating head (10) has a firs t cavity (22) that communicates with the port (18) and at least one further cavity (26) that surrounds the first cavity (22). The first and further cavities (22 & 26) are connected by conduits (24 & 30) to respective vacuum pumps (25 & 31), which apply differential negative pre ssure to the first and further cavities {22 & 26), and the chamber (15) is evacuated by way of the first cavity (22). Evacuation of the chamber (15) may be effected whilst the glazing is subjected to high temperature out gassing.