Device and method for applying a flowable medium onto a moving surface

An apparatus for applying a flowable medium (2, 2′) to a continuously transported web (1) which lies on a counterroll (5) in a region where the medium (2, 2′) is applied, comprising the following:

• a) a continuously rotating engraved roll (4) adapted for applying medium (2, 2′) to web (1),
• b) the engraved roll (4) has on its circumferential surface (6) a plurality of engraved grooves (19),
• c) an application head (3) adapted for applying medium (2, 2′) to the circumferential surface (6) of the engraved roll (4),
• d) the application head (3) is arranged below the engraved roll (4), and the engraved roll (4) is arranged below the counter roll (5),
• e) the application head (3) has a pre-chamber (7) and a main chamber (8), open toward the circumferential surface (6) of the engraved roll (4), for the medium (2, 2′) to be applied,
• f) the pre-chamber (7) and main chamber (8) are separated from one another by a center sealing member (10), with the sealing member (10) lying on the circumferential surface (6) of the engraved roll (4),
• g) the pre-chamber (7) is bounded on its exposed exterior side by a front doctor blade (13), which lies to form a seal on the circumferential surface (6) of the engraved roll (4) and the main chamber (8) is limited on its exposed exterior side by a back doctor blade (17) which also lies to form a seal on the circumferential surface (6) of the engraved roll (4), and
• h) pre-chamber (7) and main chamber (8) are adapted such that the pressure of the medium (2) in the pre-chamber (7) is greater than the pressure of the medium (2′) in the main chamber (8).