Abstract: The invention relates to an apparatus for applying, by means of a slotted nozzle device formed between a stationary incoming nozzle lip and a trailing nozzle lip, a thin layer of coating material to a porous material web that passes over a counterpressure roll, wherein a doctor bar with an essentially circular cross-sectional shape is disposed on the trailing nozzle lip; this doctor bar has on its periphery at least one flattened section that runs across the entire longitudinal extension of the doctor bar and is rotatably supported within a doctor support so that the flattened section is adjustable at a setting angle relative to the counterpressure roll.

Abstract: An apparatus for applying a thin layer of a coating material (2) to a web of material (4) passing over a counter-pressure roller (3), with a slot nozzle device (1) includes a vertical nozzle box (5) with an upper nozzle slot (7) between inlet (8) and outlet (9) nozzle lips and a laterally mounted storage tank (6) for coating material (2). In order to keep the layer thickness the same and without coating flaws and thickened edges according to the operating speed and fluctuations in thickness of the web of material (4), the storage tank (6) is mounted on the nozzle box (5) in such a way that the liquid level of the coating material (2) in the storage tank (6) and in the nozzle box (5) is essentially the same. Furthermore, appropriately in the nozzle box (5) is provided a driven continuous conveyor roller (10) mounted eccentrically in a roller chamber (11) in the path of the coating material ( 2).