There is described a shutter for a valve for controlling an air flow; shutter is selectively rotatable about an axis and adapted to be housed inside a body of valve, and comprises a surface disposed about axis; surface comprises at least one first curved portion shaped eccentrically relative to axis so as to define, in use and together with body, at least one first passage for the air flow.

A device for generating a liquid film of a liquid medium in a film bag comprising two accumulating surfaces, a braking element, and a running surface are described herein. The device may further comprise a tensioning element. Also provided is an assembly for the controlled exposure of a liquid medium in a film bag using physical radiation and a method for generating a liquid film of a liquid medium in a film bag.