Ventilation fan system with smoke detector speed control

摘要: This invention relates to a ventilator wherein an electronic circuit is actuated when detecting element detects the existence of any smoke or gas while fan in manually selected slow rotating node operation stand-by halting position, and then automatically put into full rotation order expel such as carbon monoxide, also for specified period after completion this expelling kept during above through function delay-off circuit, with shutter ventilating window being open by means switch network.