Abstract: A gas blower comprises a generally cylindrical housing containing a generally annular radially symmetric impeller chamber and a generally annular and generally radially symmetric plenum chamber. The housing has a gas inlet opening to the impeller chamber and a gas outlet opening from the plenum chamber. The radially outer portion of the impeller chambers in fluid communication with the radially outer portion of the plenum chamber. The blower further comprises a rotatable drive shaft extending axially within at least a portion of the housing and an impeller mounted on the drive shaft for rotation within the impeller chamber. The impeller is mounted for a generally axially intake of gas from the inlet opening and a generally centrifugal radially symmetric exhaust of the gas within the axial component in the axial direction opposite to the direct of the gas intake.