Self closing ventilation unit - has motor driven centrifugal fan sliding axially with end wall shutting opening

摘要

The self-closing ventilation unit is driven by an electric motor, being for mounting in a window-frame etc. The fan (6) is a centrifugal one, sliding axially, and having a sidewall (13) extending outside the blades (14) to form a cover for the outlet opening. A mechanism causes the fan to slide, dependent on motor speed, so that when running the cover frees the opening, and when switched off shuts it. Both fan and motor rotor can be fixed to a shaft, the rotor being thrust out from inside the stator when switched off. On switching on, magnetism pulls it back inside the stator and the cover frees the opening.