Patent ID: 7022185

Claim:
An apparatus for treating a moving web of paper or paperboard with a web treatment substance, comprising: an applicator comprising: an application chamber located proximate and facing a moving web, the chamber being delineated by the web, a plurality of walls and a sealing means at ingoing and outgoing sides of the web into the application chamber; and at least one linear nozzle array having at least one spray nozzle operable to spray a web treatment substance onto a surface of the web when a portion of the web is within the application chamber; a suction chamber communicating with the application chamber through an inlet opening positioned at a lower edge of one of the walls delineating the application chamber; and a suctioning means communicating with the suction chamber and the application chamber and being operable to remove mist and accumulation of the web treatment substance in the application chamber by establishing a flow in the suction chamber and the application chamber by establishing a pressure in the application chamber lower than ambient pressure in space surrounding the apparatus, and the pressure in the suction chamber lower than the pressure in the application chamber, so that a free flow direction of substances is from the space surrounding the apparatus into the application chamber, from the application chamber into the suction chamber, and from the suction chamber into the suctioning means, so that web treatment substance sprayed onto the surface of the web but not adhered to the web and formed condensate within the apparatus is removable by the suctioning means.