Air pump for use in dusty environment

Apparatus for use in pumping particle laden gases comprising:

• a housing having a generally cylindrical passageway therethrough, said passageway having an inlet and an outlet;
• deflector means supported at said inlet for imparting an inertial force to incoming particles for directing them toward the housing wall;
• a driven bladed rotor mounted in an intermediate region of said passageway;
• an axially extending shroud of circular cross section surrounding said bladed rotor and dividing said passageway into inner and outer axially extending passageways, the leading edge of said shroud being adjacent the lee side of said deflector means and forming therebetween an annular inlet in communication with the inlet side of said bladed rotor;
• and
• an annular shaped ejector nozzle at the trailing edge of said shroud having a primary nozzle in communication with the outlet of said bladed rotor and having a secondary nozzle in communication with said annular outer passageway on the outside of said shroud, whereby gases drawn through said annular inlet by said bladed rotor and forced at high velocity through said ejector primary nozzle provides a pressure drop for drawing particle laden gases through the ejector secondary nozzle and from the annular outer passageway.