Blower muffler and vibration isolation
View Patent ↗An air impeller with both sound attenuation and vibration isolation means in a compact assembly. Three muffler chambers are provided preceding the inlet to the impeller each with sound absorbing foam material and vibration isolators are provided at both inlet and discharge sides of the impeller.
1. An air impeller with muffler and vibration isolation means comprising a housing defining a chamber for receiving and enclosing an air impeller and an associated electric drive motor, an impeller and electric drive motor disposed in said chamber, and impeller having an air inlet opening and a discharge opening in the housing having an air inlet opening remote from the impeller inlet opening and a discharge opening in communication with the impeller discharge opening, said housing also includes at least two sound attenuation chambers arranged to receive air seriatim from said housing inlet opening and discharge the same to said impeller inlet opening, and means defining an opening for the passage of air from one of said chambers to the other, the area of said opening and the length of each of said chambers being selected for optimum desired sound attenuation, and flexible elastomeric vibration isolators being provided at both housing inlet and discharge openings.
2. An air impeller with muffler and vibration isolation means as set forth in claim 1 wherein the housing defines three sound attenuation chambers with interconnecting air passageways, and wherein the areas of the openings and the length of the chambers are selected for optimum desired sound attenuation.
3. An air impeller with muffler and vibration isolation means as set forth in claim 1 wherein the walls of the chambers are lined with a soft open celled acoustical foam for enhanced sound attenuation.
4. An air impeller with muffler and vibration isolation means as set forth in claim 1 wherein the lengths of the chambers and the areas of the opening therebetween are selected to provide sound attenuation in the frequency range approximately 60 to approximately 2000 hz.
5. An air impeller with muffler and vibration isolation means as set forth in claim 2 wherein the housing takes a generally rectangular configuration with the impeller, drive motor and an elongated tubular air discharge element on one side and the sound attenuation chambers on the other, the latter being formed with the shortest of three chambers receiving ambient air from the housing air inlet and discharging to the longest in a linear arrangement, the third chamber being arranged parallel and adjacent to the second chamber and receiving air from the second chamber through a short U-turn passageway and discharging to the impeller inlet.
6. An air impeller with muffler and vibration isolation means as set forth in claim 5 wherein the housing comprises a molded thermoplastic member having a back wall and short interconnected side walls and a flat steel cover plate over at least a portion of its open end.
7. An air impeller with muffler and vibration isolation means as set forth in claim 5 wherein the tubular discharge member is the vibration means for the discharge opening and the vibration isolation means for the inlet opening takes the form of a disc having a central inlet opening.