Abstract: A running substrate which is coated with a solvent-containing material is conveyed through several sections of a drying unit and is dried with a stream of inert gas which is conveyed counter to the direction of movement of the substrate. The temperature of inert gas is reduced during flow from section to section and the quantity of solvent in the inert gas is maintained slightly below saturation value during the initial stage of the drying operation to thus enhance the surface finish of the coating. The stream of inert gas is circulated along an endless path a portion of which coincides with the path for the substrate, and the inert gas is heated to maximum drying temperature before it enters the downstream end of the path for the substrate.
Abstract: The uncoated side of a running web-shaped substrate, the other side of which carries a layer containing an evaporable solvent, is contacted by at least one idler guide roller which is rotated by the substrate. The angle of contact between the uncoated side of the substrate and the peripheral surface of the guide roller is increased by streams of compressed conditioning gas which is discharged by the orifices of two venturis one of which is located immediately upstream of the guide roller and directs gas counter to the direction of advancement of the substrate. The other venturi is located immediately downstream of the guide roller and its orifice discharges gas in the direction of advancement of the substrate.
Abstract: A running web the upper side of which is coated with one or more films containing a volatile substance is heated from below in a housing which contains a driven cooled condensing roller in the space above the path for the web. The vaporous substance which is expelled as a result of heating of the web is condensed on the peripheral surface of the cooled roller, and the film of condensate is stripped off the peripheral surface to enter an evacuating trough. The rate of condensation can be regulated by changing the rotational speed of the roller in dependency upon variations of pressure of vaporous substance above the running web and/or in dependency on the monitored rate of escape of vaporous substance into the atmosphere.
Abstract: Apparatus for applying one or more films of coating material to a running substrate of paper or the like has an endless belt which is trained over pulleys so that its upper reach advances toward a transfer station for coating material and its lower reach advances toward a station for the application of liquefied solvent-containing material. The underside of the lower reach of the belt is heated by a set of infrared heaters so that the liquefied coating material is applied to preheated portions of the belt. This promotes and contributes to predictability of expulsion of solvent from the film along the upper reach of the belt and ensures more predictable solidification of coating material ahead of the transfer station.