Patent ID: 8281734
Filing Date: 2012-10-09
Classification: D06B,F16J

Abstract:
1. An apparatus for treating a travelling web of material in a predetermined gaseous atmosphere comprising a process chamber through which a moving web of material is transported from an inlet at a first end of said process chamber to an outlet at a second end of said process chamber and an introducer and controller for introducing and controlling gas intended to provide the predetermined gaseous atmosphere within said process chamber, wherein said inlet and outlet each comprise a sealing means designed to enable passage of the web of material therethrough whilst minimising the ingress of an external gas boundary layer around the web of material characterised in that said apparatus also comprises one or more re-circulation channels adapted to re-circulate gases within said process chamber from said second end of said process chamber to said first end of said process chamber thereby substantially negating any pressure difference within said process chamber between said inlet and outlet, wherein said apparatus further comprises at least one intermediate chamber upstream and/or downstream of said process chamber, said at least one intermediate chamber comprising a purging system for purging the travelling web of material with required gas prior to entry into or subsequent to exit from said process chamber so as to replace fluid trapped in the web of material with a required gas, and a gas remover for extracting purged fluids from said at least one intermediate chamber, and wherein adjacent intermediate chambers of said at least one intermediate chamber are linked by one or more channels adapted to supply required gas, which was not previously recirculated, into said intermediate chamber neighbouring said process chamber and then sequentially through the other intermediate chamber in series as they progress away from said process chamber so as to provide a counter-current of required gas moving through said intermediate chambers in the opposite direction to the direction of passage of the web of material.