Roll-coating machine for applying coating colors onto a paper web

A roll-coating machine for the application of coating colors onto a paper web, comprising:

• (a) a coating roll that rotates in a coating color pool;
• (b) a trough to receive the color pool and having a coating color inlet, a guide wall in a spaced relationship with the ascending region of said coating roll with a first overflow edge, and an overflow channel connected thereto for a first overflow stream;
• (c) a mating roll that is wound with a paper web and defines a nip entrance zone and a nip exit zone in cooperation with said coating roll, and rotates in a direction opposite that of said coating roll;
• and
• (d) a machine-wide guide shield that extends into said nip entrance zone, forms a flow channel in cooperation with the surface of said coating roll, and has a second overflow edge for a second overflow stream on its downstream end, wherein
• said guide shield has a bypass channel equipped with a valve on its downstream end to divert the second overflow stream in the direction of said valve;
• said guide shield forms a restrictor with said paper web at a location forward of the bypass channel relative to the direction of rotation of the mating roll;
• the restrictor defines a third overflow edge for a third overflow stream;
• and
• the guide shield has fin- or rib-like protrusions on its side facing the surface of the coating roll that extend in the direction of flow and form individual channels between them.