Apparatus for coating substrate with e.g. melted thermoplastic - has elastic backing roller under pressure from cylinder containing internal pressure member with slit which supplies melted coating

摘要

A device to coat a substrate with liquid, pastes or plastic materials, and thermoplastics in particular, has a means of melting the coating material and a coating head where the fused substance is applied to the substance through a perforated cylinder; this cylinder and a counter-roller provide a coating gap through which the substrate is drawn; the distance between the axes of the cylinder and roller can be less than the sum of their radii but can be adjusted. In the figure, the substrate (1) is passed through the gap (2) between a perforated (e.g. metal) cylinder (3) and an elastic backing roller (4). The distance (a) between axes is less than the sum of the radii (r1,r2) i.e. the roller (4) is compressed at the gap (2). The inner coating head (5) is pressed against the interior face (6) of the cylinder (3). ADVANTAGE - The coating gap remains constant during operations (unlike existing systems in which the gap varies according to the temp. of the coating).