Radial blower, especially for oil burners

Claim 1

A radial fan for conveying air comprising a rotor impeller having blades extending approximately radially of the rotor and a casing having axially spaced sides with a lateral inlet in one side and a spiral wall extending approximately 270* about said impeller and integral, parallel continuations of the ends of said spiral wall forming parallel walls of an outlet of said casing, said spiral wall having its first end spaced from said impeller with the spacing of said spiral wall from said impeller increasing toward the other end, said first end being joined to the corresponding parallel wall by a transition portion which is concave toward the opposite parallel wall and is joined to the first end of said spiral wall by an integral sharp bend forming a projection directed in a direction opposite to the direction of rotation of said impeller, so that the air from said impeller blades is divided into a main current out from said impeller discharged through said outlet, and another current deflected by said concave transition portion toward the periphery of said impeller into said blades, said inlet being offset relative to the axis of said impeller so that said side wall covers one circumferential portion of said impeller on one side and the inlet opening exposes a circumferential portion of said impeller on the opposite side and said inlet has a converging nozzle projecting inwardly from said side wall toward said impeller.