Patent 5283960 Issued on February 8, 1994. Estimated Expiration Date: July 21, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
A drying apparatus is disclosed for drying a web of paper. The apparatus includes a plurality of top felted drying sections for drying the web. Each of the drying sections is arranged in succession such that the web is restrained against cross-machine and machine directional shrinkage during passage of the web through the plurality of drying sections. A further single drying section only is disposed downstream relative to the plurality of drying sections such that the web extends between the plurality of drying sections and the further drying section. The further drying section includes an upper tier of dryers and an upper plurality of rolls which are disposed between adjacent dryers of the upper tier. An upper felt extends alternately around each dryer of the upper tier and each roll of the upper plurality of rolls. The further drying section also includes a lower tier of dryers and a lower plurality of rolls disposed between adjacent dryers of the lower tier. A lower felt extends alternately around each dryer of the lower tier and each roll of the lower rolls. The arrangement is such that the web extends in open draw between each dryer of the upper and lower tiers so that any tendency of the web to curl is controlled during movement of the web through the further drying section.
Paper Age; Nov. 1991; pp. 12-13 by Tim Bal and J. Yli-Kauppila
"Effect of Water Retention Value (WRV) on the Paper Web Drying Process"; Cellulose Chem. Technol.; pp. 451-464, 1986
Paper given by Valmet at Apr. 1989 CPAA Printing Conference; untitled; pp. 1-14
"Relation Between Drying Stresses . . . " by M. Htun and A. de Ruvo; Published Sep. 1977; pp. 2-13; Conference Literatur