Corrugating machine for producing corrugated board and related method

摘要

The machine for producing a corrugated board comprises a first corrugating roller (3) and a second corrugating roller (5) defining a corrugating nip (7) through which a first web material (N1) passes. A gluing unit (9) is furthermore provided, cooperating with the second corrugating roller (5) to apply a glue on crests of the first web material (N1) formed in the corrugating nip (7). A pressing member (11) cooperates with the second corrugating roller (5) to press a second web material (N2) against the crests of the first web material (N1). A pressure regulating system is provided to adjust the pressure of the pressing member (11) against said second corrugating roller (5). This pressure regulating system comprises at least a first pressure chamber (27C) associated with a first abutment (33) for said pressing member (11). The pressure chamber (27C) contains a pressure liquid and is provided with a pressure transducer (37) to detect the pressure inside it. A control unit (69) causes controlled opening of a stop valve (39) when the pressure detected by the pressure transducer (37) is outside a tolerance range around a desired pressure value. The opening of the stop valve puts the first pressure chamber (27C) into fluid connection with a hydraulic circuit (53-60) for pumping the pressure liquid.