Abstract: A web to be coated travels over a deflecting roll and underneath a slot nozzle from which a curtain of a coating material falls. A suction box open toward the roll and web has upstream and downstream ends and extends full axial length of the roll. An upstream seal on the upstream side of the box is juxtaposed with the web, extends the full axial length of the roll, and has upstream and downstream edges extending transverse to the web-travel direction. A similar downstream seal is provided on the downstream side of the box juxtaposed with the web. The downstream-seal downstream edge is spaced upstream in the direction from where the curtain falls on the web. Air is withdrawn from the box between the seals to suctionally strip a boundary layer of air from the web between the seals.

Abstract: A coating system for a web traveling in a web-travel direction has a slot nozzle from which a curtain of a coating material falls on the traveling web and a pair of guide elements flanking the slot nozzle and having confronting and vertical inner faces engaging and defining edges of the curtain. Respective aspiration elements fixed at lower ends of the guide elements have inner faces vertically aligned with and forming vertical continuations of the inner faces of the respective guide elements, and each formed with a vertical and inwardly open aspiration groove and with a transversely extending vacuum passage open into the respective groove. Respective floors on the aspiration elements downwardly close the respective aspiration grooves and are each formed with a sharp inwardly directed edge closely spacedly juxtaposed with the web. Excess coating material is aspirated from the curtain through the vacuum passages.

Abstract: Known devices for coating moving material webs comprise a slotted nozzle (1), from which the coating material is discharged in a free-flowing curtain and which has a guide element (2) for the edge of the curtain, said element extending downwards on each side in the immediate vicinity of the discharge gap (3). Suction elements for evacuating the coating material are located in the edge region of the web. According to the invention, a suction element (6) is fixed on the lower end of each guide element (2), the inner face of said suction element that points towards the curtain being aligned with the inner face of the guide element (2). A suction channel (7), which is connected to a suction line (8), is guided through the suction element (6), said channel opening into a suction tip that runs perpendicular to the curtain plane (9) at the lower end of the inner face.

Abstract: In order to suction the air boundary layer from a running web of material (1) before coating with a curtain-coater, a suction box (8) is arranged in the area of a roller (4) deflecting the web of material (1), said suction box having the following characteristics: a) the suction box (8) extends in its breadth along the axial length of the deflection roller (4); it is open towards the deflection roller (4) and attached to a suction blower, b) it has a corresponding seal (10, 11) on the inlet and the outlet sides, which form a gap (12, 13) with the web (1) and extend along the axial length of the deflection roller (4), wherein at least the end of the seal (10) on the inlet side and the beginning of the seal (11) on the outlet side are located on the deflection roller (4) in the deflection area of the web (1); c) the suction box (8) has a front-face seal (14) on each of the front faces of the deflection roller (4), which extend outside adjacent to the seal of the front face, parallel thereto and at a close dista