Air pump with primary and secondary inlet flow channels

An air pump useful in pumping gases containing abrasive particles comprising:

• an outer cylindrical housing having an axially extending inner duct, said duct having an inlet and an outlet;
• a cylindrical shroud mounted within the housing to divide the duct into inner and outer axially extending channels;
• a source of primary air flow being relatively free of contaminants connected to the inner channel;
• a source of secondary airflow which is desired to be pumped, said source being connected to the outer channel of the duct;
• a streamline body of revolution mounted within the housing on the axis thereof, said body positioned at the inlet end of the inner channel to cause a uniform annular primary airflow, said body supported by equi-spaced radial inlet struts connecting said streamline body of revolution with said outer housing, each of said struts along its length penetrating through a close fitting opening in the outer wall separating the primary and secondary flow channels;
• a powered rotor mounted within the housing for rotation about the axis thereof, downstream of the streamlined body of revolution, the blades of said rotor extending into the inner channel of the duct to accelerate the primary airflow;
• an annular shaped ejector nozzle formed in the outlet end of the shroud downstream of the rotor to cause further acceleration of the primary airflow;
• a suction chamber formed in the duct downstream of the ejector nozzle to receive the high velocity primary airflow therefrom, and connected to the outer channel to receive the secondary airflow therefrom, the flow of high velocity primary airflow into said chamber serving to pump the secondary airflow through the outer channel;
• and
• means connected to the suction chamber to dispense the contents of the suction chamber from the pump.