Patent ID: 7118474

Claim:
A device for controlling airflow, for use in connection with ventilation of room/cell/zone, designated the special volume ( 1 ), having a degree of clean air different from surrounding/adjacent rooms, designated the reference volume ( 2 ), characterized in a system that is operated by air pressure alone including a minimum of three channels/channel systems ( 6 , 9 , 10 ) being hydraulically connected in a common junction ( 8 ), and in that air can be fed or carried off in at least one of the channels/channel systems, designated the ventilation channel ( 9 ), and that in at least one of the other channels/channel systems, designated the reference channel(s) ( 10 ), is a low hydraulic impedance from the common junction ( 8 ) to the reference volume ( 2 ) and that at least one of the other channels/channel systems ( 6 ) extends between the common junction and the special volume ( 1 ) and has a design or a device, designated the resistor element ( 7 ) which provides a suitable drop in pressure when air flows through and that between the reference volume ( 2 ) and the special volume ( 1 ) is a closable access path ( 3 ).