Air flow housing

A housing for directing air propelled by an impeller through an object such as a motor has several arcuate vanes which direct the air radially inward towards ports associated with each vane. The vanes of the housing are placed non-symmetrically about the housing, and each vane has a corresponding vane located 180.degree. around the housing. Sharp corners are eliminated on the back of each vane where the vane meets a main body, where each vane meets an outer rim and/or where each vane meets a base portion of the housing. The disclosed housing increases efficiency in moving air while decreasing the noise of the airflow.

BACKGROUND OF THE INVENTION 
The present invention relates generally to devices for directing airflow to 
an object and, more particularly, to devices for directing air propelled 
by an impeller through a housing and into a motor. 
BACKGROUND ART 
An impeller for moving air, such as may be used in a vacuum cleaner, is 
often enclosed within a housing which directs air downstream from the 
impeller as exhaust or for particular uses. For instance, if the impeller 
is driven by an electric motor, it may be desirable to direct the air 
moved by the impeller through the interior of the motor for cooling. The 
design of such a housing, including any vanes which might be used to 
direct the air, is of critical importance. A properly designed housing can 
add not only to the efficiency of the system in moving air and increasing 
air pressure, but can also minimize noise caused by the air flow. 
Several patents disclose air directing elements of air moving systems 
having vanes with uncommon shapes in an effort to increase efficiency or 
reduce noise. U.S. Pat. No. 4,669,952 discloses a quiet by-pass vacuum 
motor having a fan end bracket with separating wedges or members which 
extend from an outer wall to an inner wall and define passageways to 
exhaust openings. Each wedge has what appears to be a generally radiused 
curve near the inner wall which flattens out towards the outer wall. The 
portion of the wedge near the outer wall is thickened as compared to the 
portion of the wedge near the inner wall. 
U.S. Pat. No. 4,859,144 discloses a motor fan system having a non-rotatably 
mounted interstage and afterstage. Circumferential portions of the vane 
walls of the interstage and afterstage are turned relative to inner 
portions such that the walls of the circumferential portions face axially 
and the inner portions face radially. Junctions between the inner portions 
of the vanes and a base wall form sharp corners. 
In addition to stationary vanes within housings, several patents disclose 
unusually shaped vanes on impellers or other moving parts. For instance, 
U.S. Pat. No. 3,398,866 discloses an impeller for a dishwasher pump where 
the vanes of the impeller are spaced unequally about the impeller. 
Similarly, U.S. Pat. No. 3,006,603 discloses irregularly spaced blades on 
a turbine. However, these patents do not disclose or suggest that the 
vanes may be stationarily disposed within a housing. 
SUMMARY OF THE INVENTION 
In accordance with one aspect of the present invention, a housing for 
directing air to an object has a main body portion including a first 
plurality of ports spaced about a periphery thereof and an outer rim 
surrounding the main body portion. A base portion extends between the main 
body portion and the outer rim. A second plurality of vanes is carried on 
the base portion and each vane extends from the outer rim to one of the 
ports on the periphery of the main body portion wherein the vanes are 
spaced in a non-symmetric fashion about the main body portion. 
The housing may have an even number of vanes and each vane has a 
corresponding vane located 180.degree. around the housing. There may be 
eight vanes on the housing. 
Each vane has a port-facing side and the port-facing side may be curved to 
direct air towards the port adjacent the vane. The port-facing side of 
each vane may intersect the base portion at a right angle. The port-facing 
side of each vane may also be nearly tangent to the rim where the 
port-facing side of the vane extends to the rim. 
Each vane has a back-facing side which intersects the main body with a 
curved surface. The back-facing side may intersect the outer rim with a 
curved surface and may intersect the base portion with a curved surface to 
direct air away from the back-facing side. 
Further, the outer rim may intersect the base portion with a curved surface 
to direct air away from the rim and the vanes may be formed integrally 
with the main body portion, the base portion and the outer rim. 
Still further, the housing may be used in combination with a foam ring 
placed adjacent the vanes. 
In accordance with another aspect of the invention, a housing has a main 
body portion including a first plurality of ports spaced about a periphery 
thereof, an outer rim surrounding the main body portion and a base portion 
extending between the main body portion and the outer rim. A second 
plurality of vanes is carried on the base portion and each vane extends 
from the outer rim to one of the ports on the periphery of the main body 
portion. Each vane has a port-facing side, which is curved to direct air 
towards the port adjacent the vane, and the port-facing side of each vane 
is nearly tangent to the rim in the area where the port-facing side of the 
vane extends to the rim. 
In accordance with another aspect of the present invention, a housing has a 
main body portion including a first plurality of ports spaced about a 
periphery thereof, an outer rim surrounding the main body portion and a 
base portion extending between the main body portion and the outer rim. A 
second plurality of vanes is carried on the base portion and each vane 
extends from the outer rim to one of the ports on the periphery of the 
main body portion wherein each vane has a port-facing side which 
intersects the base portion at a right angle. Each vane has a back-facing 
side and the back-facing side intersects the main body with a curved 
surface. 
In accordance with yet another aspect of the present invention, a housing 
has a main body portion including a first plurality of ports spaced about 
a periphery thereof, an outer rim surrounding the main body portion and a 
base portion extending between the main body portion and the outer rim. A 
plurality of vanes is carried on the base portion and each vane extends 
from the outer rim to one of the ports on the periphery of the main body 
portion wherein each vane has a back-facing side which intersects the 
outer rim with a curved surface. 
In accordance with still another aspect of the present invention, a housing 
has a main body portion including a plurality of ports spaced about a 
periphery thereof, an outer rim surrounding the main body portion and a 
base portion extending between the main body portion and the outer rim. A 
second plurality of vanes is carried on the base portion and each vane 
extends from the outer rim to one of the ports on the periphery of the 
main body portion wherein the vanes are spaced in a non-symmetrical 
fashion about the main body portion. Each vane has a port-facing side and 
a back-facing side wherein the port-facing side is curved to direct air 
towards the port adjacent the vane. The port-facing side of each vane also 
intersects the base portion at a right angle and is nearly tangent to the 
rim in the area where the port-facing side of the vane extends to the rim. 
The back-facing side intersects the main body, the outer rim and the base 
portion with curved surfaces. The outer rim intersects the base portion 
with a curved surface to direct air away from the rim.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring initially to FIGS. 1 and 2, a motor assembly indicated generally 
at 20 has a motor 22 that rotates a drive shaft 24. The drive shaft 24 is 
connected to an impeller 26 by a spacer 27, washers 28A and 28B and a nut 
29. The impeller 26 draws air through an opening 30 in a lower housing 32 
(FIG. 1) and directs the air radially outward. Air directed by the 
impeller 26 flows around the outside of a baffle plate 34 through a foam 
ring 36 and into an upper housing 38. As will be discussed further below, 
air in the upper housing 38 is directed radially inward by features of the 
upper housing 38 and into the motor 22. The air may be used to cool the 
motor 22 and comprise working air for a dry vacuum cleaner. 
Referring now to FIG. 8, the lower housing 32 has a sidewall 40 which is 
secured to the upper housing 38 by means of interengaging projections and 
mating recesses or dimples (not depicted). The impeller 26, shown in 
additional detail in FIG. 5, has a lower wall 42 and an upper wall 44. 
Lower wall 42 has a large circular opening 46 through which air enters the 
impeller 26 from the opening 30 in the lower housing 32. The upper wall 44 
has an opening 48 through which the spacer 27, the washers 28A-B and the 
nut 29 (FIG. 2) attach the drive shaft 24 to the impeller 26 for rotation. 
The impeller 26 has several curved vanes 50 A-F located between the lower 
wall 42 and upper wall 44. When the impeller 26 rotates in a 
counter-clockwise direction as shown in FIG. 8, air entering through the 
opening 46 is moved by the vanes 50A-F radially outward. 
The baffle plate 34 has an opening 52 through which drive shaft 24 passes. 
Holes 54A-D permit screws 56A-D to pass through baffle plate 34 for 
attachment on the upper housing 38. The foam ring 36 is located between 
the baffle plate 34 and the upper housing 38. The baffle plate 34 has a 
diameter slightly less than the diameter of the upper housing 38 (see FIG. 
2) so that air can pass around the baffle plate 34 and into the upper 
housing 38. 
The upper housing 38 includes a main body 58 having an opening 60 
surrounded by an offset ring 61 through which drive shaft 24 passes so 
that the drive shaft 24 is able to rotate without imparting torque to the 
upper housing 38. Ball bearings (not depicted) may be provided above the 
offset ring 61, surrounding the drive shaft 24 to facilitate the rotation 
of the drive shaft 24. In a sidewall 62 of the main body 58 are ports 
64A-H, some of which extend well into the top portion of the main body 58. 
Preferably, the ports 64A-H are equal in size to optimize performance and 
reduce noise levels. Around the outside of the housing 38 is a rim 66 
which is connected to the main body 58 by a base 68. 
As can be seen from FIG. 4, the back of upper housing 38 has a number of 
features on the main body 58 which provide strength or allow the upper 
housing 38 to attach or mate with the motor 22. Thus, the precise shape of 
the back of upper housing 38 will be dependent upon the motor used. 
Threaded openings 67A and 67B are provided to bolt the upper housing 38 to 
the motor 22. Baffles 65A and 65B help direct air into the center of the 
motor instead of allowing it to pass along the outside of the motor. In 
addition, the back of the upper housing 38 has six projections 69A-F which 
prevent air from merely spinning around in the area inside of the ports 
64A-H, but instead forces the air axially into the motor 22. 
Referring now to FIG. 3, each port 64A-64H of upper housing 38 has a vane 
70A-H associated therewith. The vanes 70A-H are not located symmetrically 
about the upper housing 38, but are instead placed at varying distances or 
angular positions about the rim 66 and the main body 58. Each vane 70A-H 
extends from the main body 58 to the rim 66 and is attached to the base 
68. Although the vanes 70A-H are not located symmetrically about the upper 
housing 38, each vane has a corresponding vane located 180.degree. around 
the upper housing 38, i.e., vane 70A corresponds to vane 70E, vane 70B 
corresponds to vane 70F, vane 70C corresponds to vane 70G, and vane 70D 
corresponds to vane 70H. Thus, the angle between adjacent vanes is 
identical to the angle between the respective corresponding adjacent vanes 
180.degree. away. Preferably, the angle between vane 70A and vane 70B or 
between vane 70E and vane 70F is 37.degree., the angle between vane 70B 
and vane 70C or between vane 70F and vane 70G is 58.degree., the angle 
between vane 70C and vane 70D or between vane 70G and vane 70H is 
32.degree.; and between vane 70D and vane 70E or between vane 70H and vane 
70A is 53.degree.. All angles are measured from the side of each port 
nearest its vane to the side of the adjacent port nearest its vane. It is 
believed that placing vanes in a nonsymmetrical fashion, which presents 
unevenly spaced obstacles for flowing air, reduces constant and even 
whistling, thereby reducing noise while minimizing any loss in efficiency. 
Each vane 70A-70H, for example the vane 70H, has two sides, a port-facing 
side 72 and a back-facing side 74. The port-facing side 72 has an arcuate 
or curved shape so as to direct air from each vane 70A-H to its associated 
port 64A-H. The arcuate shape of the port-facing side 72 of each vane 
70A-H allows the port-facing side 72 to intersect the rim 66 substantially 
tangentially at a portion 76. The substantially tangential intersection of 
the port-facing side 72 and the rim 66 allows air to be guided inwardly 
with the smoothest possible flow, which increases performance and keeps 
noise levels low. 
The back-facing side 74 of each vane 70 does not follow the contour of the 
port-facing side 72, and thus each vane 70 is of varying thickness as it 
extends from the main body 58 to the rim 66. The back-facing side 74 of 
each vane 70 intersects the main body 58 with a curved surface 78 to 
direct air towards the port-facing side 72 of an adjacent vane. Similarly, 
the back-facing side 74 intersects the rim 66 with a curved surface 80 to 
direct air away from the back-facing side 74 and towards the port-facing 
side 72 of an adjacent vane. In essence, vanes of an essentially uniform 
thickness throughout their length have been widened at each end or have 
had their intersections filled in with material to replace sharp corners 
which would otherwise be present where the vanes meet the remainder of the 
housing. It is believed that sharp corners contribute to whistling or 
noise when air is pulled across them and may also reduce the efficiency of 
the lower housing 38 in allowing air to pass therethrough. In addition to 
the curvatures of the surface 78 and the surface 80, the back-facing side 
74 may also have a gentle arcuate shape between the surface 78 and the 
surface 80, where the curvature is in the same direction as the curvature 
of the port-facing side 72. 
Referring now to FIGS. 6 and 7, the base 68 intersects the rim 66 with a 
curved surface 82 to direct air away from the rim and towards an adjacent 
port. Similarly, the back-facing side 74 of each vane intersects the base 
68 with a curved surface 84 to direct air away from the back-facing side 
74. The port-facing side 72 of each vane, however, intersects the base 68 
at a corner 86 which is nearly at a right angle. By providing a sharp 
corner, a recirculation condition, in which air flows over vanes or ports 
without exiting, is minimized. 
The rim 66 has a flange 88 running around its perimeter to seat the lower 
housing 32 when it is snapped in place on the upper housing 38. 
The specific size of the upper housing 38 will depend upon the amount of 
air to be moved and the motor with which it is used, however, the 
following dimensions relative to each other are suitable for an embodiment 
of the housing and other parts associated therewith. The diameter of the 
housing measured from the outside of flange 88 is 5.78 inches (14.68 cm). 
The diameter of the outside portion of the rim 66 is 5.64 inches (14.33 
cm) with a thickness of the rim of 0.09 inches (0.23 cm). The height of 
the entire main body 38 is 1.10 inches (2.79 cm) and the distance from the 
back of the main body 38 to the top of the rim 66 is 0.97 inches (2.46 
cm). The width of each port 64 is 0.40 inches (1.02 cm). The thickness of 
the base portion 68 is 0.12 inches (0.30 cm) and the height of each vane 
70 is 0.425 inches (1.08 cm). The height of each vane 70 with respect to 
other elements of the lower housing 38 is particularly critical for 
reducing noise and increasing efficiency. 
As noted above, many of the elements of the upper housing 38 are arcuate in 
shape or intersect other elements arcuately. Suitable radii of curvature 
for the elements are as follows: 
______________________________________ 
Element Radius of Curvature 
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port-facing side 72 
1.00 inch (2.54 cm) 
back-facing side 74 
1.07 inches (2.72 cm) 
curved surface 78 .50 inches (1.27 cm) 
curved surface 80 .22 inches (.56 cm) 
curved surface 82 .25 inches (.64 cm) 
curved surface 84 .06 inches (.15 cm) 
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The upper housing 38 may be made of Plenco 1581 I, Polyester Mineral, 
reinforced with glass, or may be made from any other suitably rigid 
material such as zincs, aluminums or other plastic materials. The vanes 
70A-H are preferably formed integrally with the rest of the upper housing 
38 and are of the same material. 
The foam ring 36 may be 0.25 inches (0.64 cm) thick, have an outside 
diameter of 5.40 inches (13.7 cm) and an inside diameter of 4.00 inches 
(10.16 cm). The foam ring 36 may be made of a ester type polyurethane foam 
which is reticulated and has 10 open pores per linear inch. 
The lower housing 32 may have an outside diameter of 5.64 inches (14.33 
cm), with a diameter of the opening 30 of 1.730 inches (4.39 cm). The 
overall height of the lower housing 32 may be 1.088 inches (2.76 cm) with 
the height from the rim of opening 30 to the top of lower housing 32 being 
0.803 inches (2.04 cm). The baffle plate 34 has an overall thickness 
(including the curved edge portion) of 0.100 inches (0.25 cm) and a 
material thickness of 0.024 inches (0.06 cm). The diameter of the baffle 
plate 34 is 5.22 inches (12.26 cm). The impeller 26 has a total thickness 
of 0.29 inches (0.74 cm) with the thickness of lower wall 42 and upper 
wall 44 of 0.020 inches (0.051 cm). The height of each vane 50 is 0.25 
inches (0.64 cm) and has a radius of curvature of 1.625 inches (4.13 cm). 
Opening 46 has a diameter of 1.875 inches (4.76 cm). The impeller is 
designed to rotate at 17,000 to 30,000 revolutions per second. 
Numerous modifications and alternative embodiments of the invention will be 
apparent to those skilled in the art in view of the foregoing description. 
Accordingly, this description is to be construed as illustrative only, and 
is for the purpose of teaching those skilled in the art the best mode of 
carrying out the invention. The details of the structure may be varied 
substantially without departing from the spirit of the invention, and the 
exclusive use of all modifications which come within the scope of the 
appended claims is reserved.