Beloit Technologies, Inc.

James P Alfano

Alfred C Li

Rajendra D Deshpande

Rex A Becker

Pamela K Hynnek

Xuekui Lan

A method and apparatus for coating a traveling paper web includes a coating applicator disposed in movably-controlled spaced adjacency with the paper web, which is supported on a rotating backing roll. The coating applicator permits a controlled introduction of a fresh portion of an aqueous slurry of coating material which is mixed with a recirculated portion of coating material in a controlled manner to prevent the formation of large vortices within the coating applicator. The coating material flows successively through mixing, convergent, and recirculation channels, all of which are defined on one side thereof by a distinct surface of a flow stabilizer which is positioned centrally in a cavity in the coating apparatus. Control of the supply of the coating material through the inlet nozzle, and the recirculation of the coating material between the recirculation and mixing channels, through a recirculation nozzle, is effected by directing the coating material through a plurality of orifices which provide a controlled back pressure in the coating material as well as to disrupt the propagation of cross-machine vortices in the coating material. The paper web is brought into contact with the coating material along a convergent channel where the coating material is carried by the traveling web over the backing roll and where the flow variation in the coating material in the convergent channel is controlled at a small-scale level. A metering blade is positioned downstream of the convergent channel to bear against the coating over the web and meter the coating onto the traveling paper web.

Method and apparatus for coating a traveling paper web

A controlled crown roll utilizes a crown support piston with a glide shoe with a cavity in the face of the glide shoe centered under the nip loading line. The cavity is surrounded by a land area, the majority of which is located away from the nip load. Use of a low viscosity hydraulic fluid, for example, 15.6 cP, with a hydraulic film thickness of 0.002 inches, results in significantly lower friction between the glide shoe and the interior surface of the rotating mantle. Recesses in the piston sides form hydrostatic thrust bearings which perform the centering function for the piston and the glide shoe.

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Janesville, WI, United States of America

James P Alfano