Control of chamber atmospheres.

摘要

A chamber such as a curing oven (or drier) 10 is inerted (i.e. its atmosphere is maintained in a non-explosive condition) during, for example, the curing of solvent-borne resin coatings. Chamber atmosphere comprising solvent vapour, inert gas (e.g. nitrogen) and small quantities of oxygen is withdrawn via conduit 14 by blower 21 at a substantially constant rate and passed into a condensation unit in which solvent is condensed. The uncondensed gas is returned to the oven 10 via a conduit 25 at a rate determined by the setting of valve 30 which is responsive to a sensor of the solvent vapour concentration in the oven 10 so as to maintain a material balance within the oven atmosphere notwithstanding changes in the concentrations of its respective constituents.