Capacitive HF gluing device for corrugated paper mfr. - uses different air pressure either side of web to provide contact pressure between web layers

摘要

The device is used to glue a second cover layer (23) to the internal corrugated layer (21) of a corrugated paper web (2) which already has one smooth cover layer (22) applied on the opposite side. Strips of glue are applied across the crests (25) of the corrugations, before forwarding the corrugated web (2) with both cover layers (22,23) through a grid of capacitive field electrodes (1). The contact pressure for gluing the cover layer (23) to the corrugated web (2) and that for pressing the web (2) against the electrode grid is obtained by different air pressures (p1,p2) on opposite sides of the web (2). Pref. the electrode grid is positioned within an air tight housing divided into two chambers (43,44) by the web (2), each supplied with heated air at a different pressure. The pressure ratio between the two chambers ensures that the friction between the web (2) and the electrode grid is a min.