Patent ID: 6105277
Filing Date: 2000-08-22
Classification: D21F

Abstract:
A support system for use with the dryer section of a papermachine including a pair of adjacent drying cylinders each having a surface which are separated by an air space and a turning roll having an interior and a surface situated adjacent the pair of drying cylinders for transferring a moving carrier fabric and paper web from the surface of one of the drying cylinders to the surface of the other of the drying cylinders as the carrier fabric and web are moved around the surface of the turning roll so that the carrier fabric is disposed between the paper web and the surface of the turning roll, wherein a pocket region is defined between the drying cylinders and the turning roll, wherein there is associated with the turning roll a vacuum source for inducing a sub-atmospheric condition within the interior of the turning roll, and wherein the turning roll includes a perforated surface to expose the paper web moving around the turning roll to the sub-atmospheric condition of the turning roll interior through the carrier fabric so that the paper web is biased against the surface of the turning roll as the web and carrier fabric are moved therearound, the system comprising:a blowbox assembly including means for directing air out of the pocket region to induce regions of sub-atmospheric conditions along an incoming run of the carrier fabric moving from the surface of one of the drying cylinders onto the surface of the turning roll and along an offgoing run of the carrier fabric moving from the surface of the turning roll to the surface of the other of the drying cylinders to reduce the likelihood of separation of the web from the carrier fabric as the web is moved with each of the incoming and offgoing run of the carrier fabric andso that upon a reduction of the energy expended by the vacuum source associated with the turning roll, constant sub-atmospheric conditions can be maintained within the pocket region by increasing the expenditure of energy of the air-directing means by an amount which is less than the amount of the reduction of energy expended by the vacuum source.