Patent ID: 11858233
Assignee: FOSBER S.P.A.
Field: Textile and paper machines (Mechanical engineering)
Classification: CPC B | IPC B

Claim 0:
1. Double facer for producing corrugated board, comprising:
a heating section comprising a series of hot plates arranged in sequence along a path for advancement of a continuous strip of corrugated board;
a cold traction section, located downstream of the heating section;
an upper flexible member extending along the heating section and along the cold traction section;
a lower flexible member extending downstream of the heating section along the cold traction section; wherein the upper flexible member and the lower flexible member are pressed towards each other to hold therebetween and pull the continuous strip of corrugated board along the path for advancement;
a first electric motor adapted to drive the lower flexible member;
a second electric motor adapted to drive the upper flexible member;
pressure members adapted to press the upper flexible member against the hot plates;
a control unit programmed to perform steps comprising:
a) pulling the corrugated board along the hot plates by the upper flexible member and the lower flexible member;
b) checking at least a first electric parameter of at least one of said first electric motor and said second electric motor, and modifying the speed of the at least one of said first electric motor and said second electric motor with respect to the speed of the other of said first electric motor and said second electric motor depending on at least said first electric parameter, to maintain a predetermined ratio between the speed of the upper flexible member and the speed of the lower flexible member within a predetermined range.