Corrugating rolls for forming corrugated paperboard medium are given a flute valley profile having a narrow channel along the valley base between arcuate segments of the valley base that parallel the channel on opposite sides of a radial plane of symmetry. This valley base channel is of such depth as...http://www.google.de/patents/US6074507?utm_source=gb-gplus-sharePatent US6074507 - Corrugating roll with improved flute profile
