Patent ID: 8156937

Claim:
A portable ventilator, comprising: a blender module, including: a pressurized gas inlet and a nebulizer drive port, wherein the blender module is configured to receive pressurized gas and aerosolized medication; a Roots blower to provide a flow of gas to a patient, including: a housing, an inlet port, an outlet port, and a pair of interlocking impellers disposed within the housing; and a noise reducing chamber to attenuate noise produced by the Roots blower, including: an enclosed interior space, an inlet coupled to a filter and configured to intake room air, an outlet coupled to the Roots blower inlet port, a first muffler tube, disposed within the interior space and coupled to the inlet, having a plurality of perforations, and a second perforated muffler tube, disposed within the interior space and coupled to the outlet, having a plurality of perforations such that the gas flows between the first and second muffler tubes only through the respective perforations; wherein the room air from the filter and the combined gas flow from the blender module are coupled to the inlet port of the Roots blower via the first muffler tube.