Curtain coating device for applying treatment substance to at least one coating roller

The invention relates to a device for applying a treatment substance, in particular starch or sizing material, to a moving paper and cardboard web (11), in particular carton cardboard or cardboard, by means of at least one curtain application device (2.1, 2.2). In order to provide an improved treatment substance coating device, the at least one curtain coating die can be supplied with a differently prepared treatment substance, and the curtain coating machine (2.1, 2.2) is supplied with an electrically and/or mechanically drivable gap adjustment device (3.1, 3.2) for the outlet gap (14.1, 14.2) of the control die lip applied to the curtain coating die, according to the invention, the at least one curtain coating device (2.1, 2.2) is designed to be able to operate in two different operating modes, in which both operating modes are combined, and the outlet gap (14.1, 14.2) is optionally set to 100 [mu] m to 500 [mu] m in the membrane operating mode or to 500 [mu] m to 2.0 mm in the trough operating mode, such t