Single or multiple stage blower and nested volute(s) and/or impeller(s) therefor

摘要

An impeller comprising: a top shroud; a bottom shroud, a plurality of vanes extending from the top shroud to the bottom shroud, each said vane including a top edge at a radially inner portion of the vane in contact with the top shroud and a bottom edge at a radially outer portion of the vane in contact with the bottom shroud, such that a radially inner portion of the vane at the bottom edge of each vane is not in contact with or adjacent the bottom shroud and a radially outer portion of the vane at the top edge of each vane is not in contact with or adjacent the top shroud.