Curtain application unit and method for applying an application medium

A curtain application unit for applying a liquid or pasty application medium to at least one surface of a moving material web or fibrous web, the curtain application unit comprising:

• an application head having a width, an exterior cladding, a nozzle gap for guiding the application medium and at least one separation edge extending over said width of said application head, said at least one separation edge configured to permit the application medium from said nozzle gap to exit said application head at said separation edge as a free falling curtain;
• at least one rinsing supply disposed within said application head between said exterior cladding and said nozzle gap for applying a flowing gaseous rinsing medium to said at least one separation edge;
• and
• at least one blocking air nozzle configured to generate an air shield for keeping air movements of ambient air away from said curtain, said air shield having an air flow direction with at least one of a component pointing away from said application head or a component pointing away from the material web.