Method for conditioning paper and paperboard webs

A method for treating a fibrous web proceeding from a dryer unit of a papermaking machine, the web having a temperature of at least about 80° C., which comprises conditioning the web by applying a flow of moistened gas including air containing a mist of water droplets to at least one surface of the moving web across its width and along at least a portion of its length from a plurality of separate, substantially overlapping flow zones wherein the flow is sufficient to create a combination of both suction and pressure forces on the same surface of the web in and about each of the zones to enhance convective heat transfer and thereby decrease its surface temperature and is sufficient to cause the droplets to reach and be absorbed by the web surface and be evaporated therefrom in order to cause the web temperature to be decreased, and thereafter calendering the web.

A method for treating a moving cellulosic web proceeding from a dryer unit of a papermaking machine, the web having a moisture content below about 8 wt. % and a temperature of above about 80° C., which comprises conditioning the web by applying a flow of moistened gas including air containing a mist of water droplets having a temperature in the range of from about 10° to about 65° C. to at least one surface of the moving web across its width and along at least a portion of its length from a plurality of spaced apart radial jet reattachment nozzles to thereby increase the moisture content of the web by at least about 0.2% and decrease its temperature, and thereafter calendering the web.

A papermaking process which comprises depositing an aqueous slurry of cellulosic and/or synthetic fibers at a consistency of from about 0.2 to about 1.5% by weight on a moving web former screen thereby forming a layer of slurry on the screen, dewatering the slurry on the moving screen to form a fibrous web, pressing the thus formed fibrous web with one or more wet press nips to provide a pressed web having a solids content in the range of from about 32 to about 45% by weight, drying the pressed web to provide a dried web having a moisture content of from about 0.2 to about 6% by weight, conditioning the dried web by applying a flow of moistened gas including air containing a mist of water droplets to at least one surface of the web from a plurality of radial jet reattachment nozzles placed adjacent the web to provide a conditioned web having a moisture content which is substantially uniformly increased across its width by at least about 0.2% relative to the moisture content prior to conditioning, and calendering the conditioned web in a calendering unit.