Web heating assembly esp. for corrugated cardboard - has microwave units in a tunnel stretched along the web path

摘要

The heating assembly for a moving paper web is formed by one or more microwave transmitter units (12). The microwave unit (12) is pref. a tunnel unit with a closed housing (13) covering the stretch between the entry and exit for the web (2). A number of microwave units (12) are arranged in a series in the direction of web (2) travel, each with a sensor (11) to monitor the web temp. or moisture content before and/or after it. The microwave unit (12) has additional heating plates (3) for the major heat action on the web (2), in front of it or over each other. A pressure system (6) holds the material against the heating plates (3). In another form, a number of microwave units are over the heated plates, across the line of web travel, with a pressure hood, enclosed by a common housing shrouding, with sensors before and/or after the hood. The web (2) is carried by draw rollers and/or a belt. USE/ADVANTAGE - The assembly, esp. corrugated cardboard, allows rapid adjustment of the radiated heat to the moisture content of the web material to give the best drying action, esp. on the bonding glue.