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 and 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 first cavity (22) that communicates wit h 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 pressure to the first and further cavities (22 & 2 6), and the chamber (15) is evacuated by way of the first cavity (22). Evacuatio n of the chamber (15) may be effected whilst the glazing is subjected to high temperature out-gassing.