Low Noise Air Movement Generator

Abstract

A low noise air generator possessing improved characteristics thereby reducing noise while maintaining or improving air flow generation and output is provided. The device may include an impeller with multiple blades, a noise reduction structure connected to a distal end of the multiple blades, an impeller housing, a tapered motor mounting surface, a heating element, a mechanical air filter, and/or an electrostatic precipitation air filter.

What is claimed: 
     
         1 . A portable air moving device comprising;
 a housing having an air intake opening and an air exit opening;   an interior space defined by said housing;   at least one air generator located within said housing comprising;
 an impeller comprising;
 a hub comprising;
 an outer wall; 
 a front wall; 
 an internal cavity defined by said outer wall and said front wall; 
 
 multiple blades connected to said outer wall of said hub and extending radially outward from said hub toward a distal end; 
 
 a noise attenuation structure connected to said distal end of more than one of said multiple blades comprising;
 a circumferential wall having a substantially cylindrical form; 
 an axis of said cylindrical form; 
 an intake edge of said cylindrical form; 
 an exhaust edge of said cylindrical form offset a distance from said intake edge along said axis of said cylindrical form; 
 
 a motor disposed substantially within said internal cavity of said hub, said motor comprising;
 a permanent magnet rotor fixedly assembled to said hub; 
 a stator rotatably connected to said rotor, said hub, said multiple blades, and said noise attenuation structure; 
 
   wherein a rotation of said impeller of said at least one air generator induces an intake air flow into said air intake opening of said housing and simultaneously generates an exhaust air flow from said air exit opening of said housing.   
     
     
         2 . The portable air moving device of  claim 1 , further comprising an electric heating element located in said interior space of said housing, wherein a temperature of said exhaust air flow is greater than a temperature of said intake air flow. 
     
     
         3 . The portable air moving device of  claim 1 , further comprising an air filter located in said interior space of said housing, wherein substantially all of said intake air flow passes through said air filter prior to exiting said housing through said air exit opening as said exhaust air flow. 
     
     
         4 . The portable air moving device of  claim 3 , wherein said air filter utilizes a mechanical filter to clean the air. 
     
     
         5 . The portable air moving device of  claim 3 , wherein said air filter utilizes an electrostatic precipitator to clean the air. 
     
     
         6 . The portable air moving device of  claim 1 , wherein said hub, said multiple blades and said noise attenuation structure of said impeller comprise a unitary structure. 
     
     
         7 . The portable air moving device of  claim 1 , further comprising an impeller housing comprising;
 an impeller housing wall defining an interior space;   an inlet opening;   an outlet opening;   at least one impeller support member; and   
       wherein said air generator is located substantially within said interior space defined by said impeller housing wall and connected to said impeller housing wall by said at least one impeller support member, said at least one impeller support member being connected to said motor and extending outwardly to said impeller housing wall. 
     
     
         8 . The portable air moving device of  claim 7 , wherein said impeller housing wall and said at least one impeller support member comprise a unitary structure. 
     
     
         9 . The portable air moving device of  claim 7 , further comprising an offset distance “A” of said at least one impeller support member defined by a minimum distance from said exhaust edge of said noise attenuation structure to said impeller support member measured in a direction of the air flow through said air generator, wherein said minimum distance is at least 25% of said offset distance between said intake edge and said exhaust edge of said noise attenuation structure. 
     
     
         10 . The portable air moving device of  claim 7 , further comprising an offset distance “A” of said at least one impeller support member defined by a minimum distance from said intake edge of said noise attenuation structure to said impeller support member measured in a direction opposite a direction of the air flow through said air generator, wherein said minimum distance is at least 25% of said offset distance between said intake edge and said exhaust edge of said noise attenuation structure. 
     
     
         11 . The portable air moving device of  claim 1 , wherein said intake edge further comprises an intake funnel including an arcuate surface extending radially outward relative to said hub. 
     
     
         12 . The portable air moving device of  claim 1 , wherein said intake edge further comprises an intake funnel including a conical surface extending radially outward relative to said hub. 
     
     
         13 . The portable air moving device of  claim 1 , wherein said motor comprises a brushless direct current motor. 
     
     
         14 . An air generator comprising;
 an impeller comprising;
 a hub comprising;
 an outer wall; 
 a front wall; 
 an internal cavity defined by said outer wall and said front wall; 
 
 multiple blades connected to said outer wall of said hub and extending radially outward from said hub toward a distal end; 
   a noise attenuation structure connected to said distal end of more than one of said multiple blades comprising;
 a circumferential wall having a substantially cylindrical form; 
 an axis of said cylindrical form; 
 an intake edge of said cylindrical form; 
 an exhaust edge of said cylindrical form offset a distance from said intake edge along said axis of said cylindrical form; 
   a motor disposed substantially within said internal cavity of said hub, said motor comprising;
 a permanent magnet rotor fixedly assembled to said hub; 
 a stator rotatably connected to said rotor, said hub, said multiple blades, and said noise attenuation structure; 
   
       wherein a rotation of said impeller generates an air flow radially confined by said outer wall of said hub and said circumferential wall of said noise attenuation structure; and 
       wherein said air flow has a direction of flow from said intake edge toward said exhaust edge of said noise attenuation structure and said direction of flow is substantially parallel to said rotational axis of said impeller. 
     
     
         15 . The air generator of  claim 14 , wherein said hub, said multiple blades and said noise attenuation structure of said impeller comprise a unitary structure. 
     
     
         16 . The air generator of  claim 14 , further comprising a mounting structure fixedly connected to said stator, said mounting structure comprising;
 a first diameter located proximate said hub and a second diameter offset a specified distance from said first diameter and said hub;   an arcuate surface extending between said first diameter and said second diameter; and   wherein said first diameter is larger than said second diameter and said arcuate surface comprises a substantially conical surface.   
     
     
         17 . The air generator of  claim 16 , further comprising at least one fastener to attach said air generator to a portable air moving device, wherein a longitudinal length of said fastener is oriented substantially parallel to said rotational axis of said impeller. 
     
     
         18 . The air generator of  claim 14 , further comprising an impeller housing comprising;
 an impeller wall defining an interior space;   an inlet opening;   an outlet opening;   at least one impeller support member; and   
       wherein said impeller is located within said interior space defined by said impeller housing wall and connected to said impeller housing wall by said at least one impeller support member, said impeller support member being connected to said motor and extending outwardly to said impeller housing wall. 
     
     
         19 . The air generator of  claim 18 , wherein said impeller housing wall and said impeller support member comprise a unitary structure. 
     
     
         20 . The air generator of  claim 18 , further comprising an offset distance “A” of said at least one impeller support member defined by a minimum distance from said exhaust edge of said noise attenuation structure to said impeller support member measured in a direction of the air flow through said air generator, wherein said minimum distance is at least  25 % of said offset distance between said intake edge and said exhaust edge of said noise attenuation structure. 
     
     
         21 . The air generator of  claim 18 , further comprising an offset distance “A” of said at least one impeller support member defined by a minimum distance from said intake edge of said noise attenuation structure to said impeller support member measured in a direction opposite a direction of the air flow through said air generator, wherein said minimum distance is at least 25% of said offset distance between said intake edge and said exhaust edge of said noise attenuation structure. 
     
     
         22 . The air generator of  claim 14 , wherein said intake edge further comprises an intake funnel including an arcuate surface extending radially outward relative to said hub. 
     
     
         23 . The air generator of  claim 14 , wherein said intake edge further comprises an intake funnel including a conical surface extending radially outward relative to said hub. 
     
     
         24 . An impeller and motor assembly comprising;
 a motor comprising;
 a permanent magnet rotor; 
 a stator rotatably connected to said permanent magnet rotor; 
 a first axis defined by an axis of rotation of said rotor; 
   an impeller hub fixedly connected to said permanent magnet rotor comprising;
 an outer wall having a cylindrical form; 
 a front wall; 
 an internal cavity defined by said outer wall and said front wall and said permanent magnet rotor located substantially within said cavity; 
 a second axis defined by an axis of said cylindrical form of said impeller hub; 
   a noise attenuation structure comprising;
 a circumferential wall having a substantially cylindrical form; 
 an intake edge of said cylindrical form; 
 a third axis of said cylindrical form being defined by said circumferential wall; 
 an exhaust edge of said cylindrical form offset a distance from said intake edge along said third axis; 
   multiple impeller blades connected to said outer wall of said hub and extending radially outward from said hub toward and connected to said circumferential wall of said noise attenuation structure;   
       wherein said first, said second and said third axes are substantially co-axial relative to one another; and 
       wherein a rotation of said permanent magnetic rotor, said hub, said multiple blades, and said noise attenuation structure generates an air flow from said intake edge toward said exhaust edge and radially confined by said outer wall of said hub and said circumferential wall of said noise attenuation structure. 
     
     
         25 . The impeller and motor assembly of  claim 24 , wherein said hub, said multiple blades and said noise attenuation structure comprise a unitary structure.