DRYER GROUP WEB TRANSFER REGION FOR PAPER MAKING MACHINE

摘要

DRYER GROUP WEB TRANSFER REGION FOR PAPER MAKING MACHINE A dry end of a paper making machine has a plurality of dryer groups each in turn comprised of a plurality of heatable dryer cylinders which alternate with reversal rolls. A respective support belt meanders past each dryer cylinder and the succeeding reversal roll in each dryer group. The web to be dried is supported on the side of each support belt to contact the heatable dryer cylinders. The reversal roll that precedes the first dryer cylinder in each succeeding group serves as a web removal roll which is wrapped by the second support belt of the succeeding dryer group. The first support belt of the preceding dryer group has the web on the side of the first belt which is toward the removal roll. The first support belt contacts the second support belt on the removal roll over a smaller part of the circumference of the removal roll than the second support belt. The removal roll transfers the web from the first support belt to the second support belt at the removal roll. There is an unsupported length of the first support belt from the last reversal roll of the first dryer group to the removal roll in the second dryer group that is of a length that the time of travel of a point on the first support belt between those two rolls is at least 0.05 seconds and preferably between 0.06 and 0.12 seconds. That zone is free of suction devices. The first support belt and possibly the second or preferably porous dryer wires. A boundary air layer deflection device opposite the removal roll deflects the boundary layer of air through the first support belt to help deflect the web off the first support belt onto the second support belt at the removal roll.