Silent ventilator unit for air conditioning system - uses flexible flap, in conduit, driven by electromagnet at resonant frequency of flap to displace air

摘要

The ventilator is installed in a conduit carrying a gas and is mounted on an angle bracket on the inside wall of the conduit. An elastically deformable flap is fastened at one end of the mounting bracket and lies generally in the direction of gas flow. The flap has an electrically driven exciter mechanism, connected part way along its length, which vibrates the flap at a frequency (1-20Hz) corresponding to its resonant frequency. The electricaly exciter comprises an electromagnet having a coil wound on a core, and an armature. The coil is fixed to the conduit wall, its axis lying parallel to the wall, and the 'U' shaped armature has the arms of the 'U' extending to the vicinity of the ends of the core. The base of the 'U' is fixed to the flap. When the electromagnet is energised the flap is displaced towards the coil.