| 摘要 |
An apparatus for wet-end coating a web on a papermachine before the web enters the dryer comprises a first endless porous fabric passing around a first couch roll equipped with a suction box. As the web passes around the first couch roll, a first applicator applies a coating on a top side of the web with the first suction box drawing some of the coating color onto and through the web so as to coat the top side thereof. The web is then conveyed on a second endless porous fabric which passes around a second couch roll equipped with a second suction box. In this case, the top side of the web is in contact with the second porous fabric so that a second applicator may apply coating color on the bottom side of the web with the second suction box, as above, drawing some of the coating color onto and through the wet web for coating the bottom side thereof. The applicators may be rolls which contact the web. Recovery systems may be provided for returning the coating color recuperated by the suction boxes to the applicator rolls. In such a case, it may be necessary to treat the recuperated coating color before returning it to the applicator rolls. Asides from coating, bonding agents, bleaching agents and various other substances including dry substances that can enhance the various properties of the paper or paperboard may be applied by the above applicators.
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