MULTIPLE ZONE LIMITING ORIFICE DRYING OF CELLULOSIC FIBROUS STRUCTURES, APPARATUS THEREFOR, AND CELLULOSIC FIBROUS STRUCTURES PRODUCED THEREBY

摘要

A limiting orifice through-air-drying apparatus for papermaking or other absorbent embryonic webs. The apparatus has a first zone (41) and a second zone (42). The first (41) zone is maintained at a differential pressure less than the breakthrough pressure, while the second zone (42) is maintained at a differential pressure greater than the breakthrough pressure. The residence time of the embryonic web to be dried with the apparatus is maintained at preferably less than 35 milliseconds on the first zone. Using the dual zone system described above, the overall energy required to run the apparatus can be reduced.