TEMPERATURE COMPENSATED VENTILATING ROLL

摘要

A ventilating roll (12) for introducing a supply of relatively dry air into the pocket spaces (P1, P3, P5) between dryer rolls (10) and the co-running fabrics (F) and paper web (W) in a papermaking machine, and removing the relatively moist air which is liberated from the traveling paper web (W) as it comes into contact with the heated dryer rolls (10). The ventilating roll (12) has a plurality of separate compartments (18, 20), some of which conduct sub-atmospheric pressure air into the pocket spaces, and some of which conduct sub-atmospheric air out of the pocket spaces. The compartments (18) conducting air into the roll alternate with the compartments (20) for conducting air out of the roll. The temperature of the internal structure of the roll is thereby balanced circumferentially about the center shaft (16) of the roll (12) and thermal bowing of the roll is kept to a minimum.