US Patent 7670118 Hot gas blowing fan

A hot-gas blowing fan includes a heat resisting impeller, a bearing, a heat insulting layer, a cooling portion, first and second magnetic couplings, a non-magnetic partition wall, and a collar. The heat insulating layer is disposed between the impeller and the bearing. The impeller and bearing are attached to the rotating shaft. The cooling portion is disposed between the heat insulating layer and the bearing. The cooling portion includes a cooling fluid that does not contact the bearing or the rotating shaft. The collar is positioned between the heat insulating layer and the impeller and is positioned between the heat insulating layer and the rotating shaft. The collar is made of a different material than the heat insulating layer.