SOUNDPROOF COVER FOR VENTILATOR AND VENTILATING PORT

摘要

PURPOSE: To provide a soundproof cover for a ventilator and a ventilating port which enables further lowering of noises leaking outside a room in the operation of the ventilator. CONSTITUTION: A fan casing 30 wrapping a fan 37 is provided with a sound absorber 100. The sound absorber 100 is provided with a pair of electrode plates not illustrated housing an electrically sensitive type fluid composition for absorbing or controlling sound waves and a variable power source 60 to apply a voltage between the pair of electrode plates while varying it.