Abstract: Processes and devices for confining, retaining and sucking off vapors, fumes, dust or similar materials including dispersed or dissolved vapor particles in a fluid medium. In order to separate these pollution particles, a fluid boundary layer or front is generated by diverting a jet against a boundary surface. The curved jet forms a vortex flow retaining the particles and transports them to the suction surfaces. The process and device are especially useful for exhaust hoods in the kitchen field and in the field of clean rooms, furthermore, in those fields, where fluid media with different characteristics are to be separated, confined and suctioned off.

Abstract: In an exhaust hood (5) for cooking places or other kinds of sources of dust or fumes, on the front edge of hood (27) blast nozzle arrangement (26) is provided, which directs blast air (22) in the form of a wall jet approximately horizontally over the underside of hood (28) against filter (17) placed in the rear area of the hood, so that the wall jet draws the flow of fumes and carries it along. In a special embodiment of the exhaust hood, on the underside of the front wall of the hood, a downward directed swirl nozzle (38) is provided, which produces vortex flow (37) which empties into the blast air flow.