U.S. patent application number 09/769720 was filed with the patent office on 2002-07-25 for blower housing with inlet guide.
This patent application is currently assigned to Jakel Incorporated. Invention is credited to Gatley, William Stuart JR..
Application Number | 20020098084 09/769720 |
Document ID | / |
Family ID | 25086327 |
Filed Date | 2002-07-25 |
United States Patent
Application |
20020098084 |
Kind Code |
A1 |
Gatley, William Stuart JR. |
July 25, 2002 |
Blower housing with inlet guide
Abstract
A blower for a furnace is provided with an inlet guide to
increase efficiency and pressure output of the blower. The blower
includes a blower housing with an inlet opening and an outlet
discharge opening. A cylindrical wall is provided around the inlet
opening and projects into a hollow interior of the blower housing.
A radial wall extends outward form the cylindrical wall toward the
discharge outlet opening to prevent recirculation of gases from the
outlet to the inlet during operation of the blower.
Inventors: |
Gatley, William Stuart JR.;
(Cassville, MO) |
Correspondence
Address: |
THOMPSON COBURN, LLP
ONE FIRSTAR PLAZA
SUITE 3500
ST LOUIS
MO
63101
US
|
Assignee: |
Jakel Incorporated
|
Family ID: |
25086327 |
Appl. No.: |
09/769720 |
Filed: |
January 25, 2001 |
Current U.S.
Class: |
415/206 ;
415/208.1 |
Current CPC
Class: |
F04D 29/4213 20130101;
F04D 29/162 20130101 |
Class at
Publication: |
415/206 ;
415/208.1 |
International
Class: |
F04D 029/54 |
Claims
What is claimed:
1. A housing for a furnace blower, the housing comprising: a
housing end wall having opposite interior and exterior surfaces and
a peripheral edge with a volute shape, an inlet opening through the
end wall spaced from the peripheral edge, and an outlet channel
having opposite inner and outer walls with the outer wall
projecting tangentially from the end wall peripheral edge and the
inner wall merging with the peripheral edge through a "U"-shaped
transition; and a cylindrical wall extending around a center axis
of the inlet opening and projecting axially from the end wall
interior surface, the cylindrical wall having an interior diameter
dimension that is less than half of an interior dimension of the
housing measured across the end wall from the "U"-shaped
transition, across the inlet opening center axis to the end wall
peripheral edge opposite the center axis from the "U"-shaped
transition.
2. The housing of claim 1, wherein: the inlet opening is circular
and the inlet opening and the cylindrical wall have interior
diameter dimensions that are equivalent.
3. The housing of claim 1, wherein: a radial wall projects axially
from the end wall interior surface and extends between the
cylindrical wall and the "U"-shaped transition.
4. The housing of claim 3, wherein: the cylindrical wall and the
radial wall have axial dimensions that are equivalent.
5. The housing of claim 3, wherein: the radial wall is a straight
wall.
6. The housing of claim 3, wherein: the radial wall is positioned
in a plane that also contains the inlet opening center axis.
7. The housing of claim 3, wherein: the cylindrical wall and the
radial wall are integrally connected to each other and are
integrally connected to the end wall interior surface and the
"U"-shaped transition.
8. The housing of claim 3, wherein: the cylindrical wall, the
radial wall, and the housing end wall are one monolithic piece.
9. The housing of claim 1, wherein: an impeller is mounted for
rotation in the housing and is axially spaced from the cylindrical
wall.
10. A housing for a furnace blower, the housing comprising: a
housing end wall having opposite interior and exterior surfaces and
a peripheral edge that spirals around the end wall, an inlet
opening through the end wall spaced from the peripheral edge, and
an outlet channel having opposite inner and outer walls with the
outer wall projecting tangentially from the end wall peripheral
edge and the inner wall merging with the peripheral edge through a
"U"-shaped transition; a cylindrical wall extending around a center
axis of the inlet opening and projecting axially from the end wall
interior surface, the cylindrical wall having a diameter dimension;
and an impeller mounted for rotation in the housing around the
inlet opening center axis and the cylindrical wall, the impeller
having a diameter dimension that is at least twice as large as the
cylindrical wall diameter dimension.
11. The housing of claim 10, wherein: the impeller outer diameter
dimension ranges from 43/4" and 5" and the cylindrical wall outer
diameter dimensions ranges from 17/8" and 21/8".
12. The housing of claim 11, wherein: the impeller has an axial
height of between 1.700" and 1.900".
13. The housing of claim 10, wherein: a radial wall projects
axially from the end wall interior surface and extends between the
cylindrical wall and the "U"-shaped transition.
14. The housing of claim 13, wherein: the cylindrical wall and the
radial wall have axial dimensions that are equivalent.
15. The housing of claim 14, wherein: the cylindrical wall, the
radial wall, and the end wall are one monolithic piece.
16. The housing of claim 10, wherein: the impeller is axially
spaced from the cylindrical wall.
17. A housing for a furnace blower, the housing comprising: a
housing first end wall having opposite interior and exterior
surfaces and a peripheral edge that spirals around the first end
wall, an inlet opening having a center axis passing through the
first end wall, and an outlet channel having opposite inner and
outer walls with the outlet channel outer wall projecting
tangentially from the peripheral edge and the outlet channel inner
wall merging with the peripheral edge through a "U"-shaped
transition; a housing second end wall having opposite interior and
exterior surfaces and a peripheral edge that spirals around the
second end wall, a shaft opening coaxial with the inlet opening
passing through the second end wall, and an outlet channel having
opposite inner and outer walls with the outer wall projecting
tangentially from the peripheral edge and the inner wall merging
with the peripheral edge through a "U"-shaped transition; a
sidewall connecting the peripheral edge of the first end wall with
the peripheral edge of the second end wall and together with the
first and second end walls defining a hollow interior of the
housing; and an impeller mounted for rotation in the hollow
interior of the housing, the impeller having first and second
annular walls adjacent the respective first and second end walls,
and portions of the first and second end walls that are adjacent
the impeller first and second annular walls are entirely
planar.
18. The housing of claim 17, wherein: a radial wall projects
axially from the first end wall interior surface and extends
between the cylindrical wall and the "U"-shaped transition of the
first end wall.
19. The housing of claim 18, wherein: the cylindrical wall and the
radial wall have axial dimensions that are equivalent.
20. The housing of claim 17, wherein: the cylindrical wall has an
outside diameter dimension and the impeller has an outside diameter
dimension that is at least twice as large as the cylindrical wall
outside diameter dimension.
Description
BACKGROUND OF THE INVENTION
[0001] (1) Field of the Invention
[0002] The present invention relates to a draft blower for a
furnace. More specifically, the invention pertains to an improved
construction of the blower housing for the blower where the housing
has a simplified, inexpensive construction that includes an inlet
guide that improves the efficiency and pressure output of the
blower.
[0003] (2) Description of the Related Art
[0004] Household furnaces utilize a draft blower or inducer to draw
combustion air into a combustion chamber of the furnace where the
combustion air is mixed with fuel and ignited to produce heat for
the furnace. By the flow created by the draft blower, the
combustion exhaust gases are drawn through a heat exchanger of the
furnace where heat from the combustion exhaust gases is transferred
to temperature controlled circulating air that is circulated
through the house by a main furnace blower. The draft blower or
inducer then draws the combustion exhaust gases from the heat
exchanger and expels the combustion exhaust gases into exhaust
piping that leads to the outside environment.
[0005] Generally speaking, these draft blowers or inducers are
designed to provide a constant high pressure flow through the
combustion chamber and heat exchanger into the exhaust piping to
ensure a proper combination of combustion air with fuel to optimize
burning and to ensure proper heat transfer in the heat exchanger.
The pressure and flow rates developed by the draft blower are a
function of the blower size, blower configuration, and the speed of
rotation of the blower impeller. Typically, the size of the blower
is specified by the furnace manufacturer so that the blower may fit
dimensionally on the furnace within a predetermined envelope. Thus,
the size of the impeller that fits within an interior of the blower
housing is also constrained by these requirements. As a
consequence, in order to increase the pressure output of a blower
having a set dimensional size, the speed of rotation of the
impeller must be increased. This requires outfitting the blower
with a larger motor with increased power and design requirements.
The larger motor often results in additional noise and increases
the overall cost of the blower. Additionally, the larger blower
motor also generally decreases overall system efficiency as it
requires increased power input.
[0006] In order to increase the pressure output of a blower without
increasing the rotational speed of the impeller or without
utilizing a larger motor, conventional blowers use a system of
baffles in the blower housing to direct the combustion gases drawn
into the blower housing and to prevent inefficiencies from fluid
recirculation or leakage within the blower housing. Conventional
blowers that do not use baffles often experience fluid
recirculation or leakage from the exhaust outlet side of the blower
housing to the vacuum inlet side of the blower housing. This causes
inefficiency in the blower that reduces the flow rate and pressure
output of the blower. Baffles have been used in the prior art to
prevent this recirculation and leakage. However, the baffles of the
prior art generally have complex geometries that include additional
structures such as elaborate directional vanes and surfaces added
to the interior of the blower housing that substantially alter the
housing from the conventional volute shape of the blower housing.
Thus, these baffles must be formed in the blower housing by
additional manufacturing steps or the baffles are added as separate
parts and installed separately into the blower housing. These added
manufacturing and/or assembly steps increase the cost of
manufacturing the blower housing.
[0007] Thus, what is needed is a blower having a blower housing
with an improved construction that generates increased vacuum
drawing input, increased interior flow rates and increased pressure
output using a conventionally sized impeller and blower motor. Such
a blower would have baffles integrally formed in the blower housing
so as to eliminate secondary assembly operations. The baffles would
be formed in a simple geometry to allow the baffles to be formed
integrally with the blower housing and to reduce material and
eliminate costly tooling for forming the blower housing and
baffles. Additionally, such a blower housing would have baffles
that do not appreciably contribute to turbulence or noise generated
in the blower housing during operation of the blower.
SUMMARY OF THE INVENTION
[0008] The present invention overcomes the shortcomings of the
prior art by providing a blower housing with an inlet guide that
increases the vacuum drawing input and the pressure output of the
blower housing. Preferably, the inlet guide is integrally formed
with the blower housing so as to reduce assembly operations.
Alternatively, the inlet guide can be added to an existing housing
by adding one or more additional parts. The inlet guide has a
simple geometry that does not require complex or intricate tooling.
The simple, two dimensional geometry of the inlet guide reduces the
material and weight of the blower housing. By forming the inlet
guide integrally with the blower housing, the cost to manufacture
the blower housing is lowered. Even when assembling the inlet guide
as a separate part with the blower housing, the assembly is
simplified and does not appreciably increase manufacturing costs.
The inlet guide also does not significantly contribute to the
internal turbulence and noise of the blower housing during its
operation.
[0009] The blower of the present invention includes a housing with
a discharge outlet opening and an inlet opening with an inlet guide
formed at the inlet opening. The inlet guide includes a cylindrical
wall that projects from a peripheral edge of the inlet opening into
the interior of the blower housing. The inlet guide also includes a
radial wall that projects axially into the blower housing interior
from an end wall of the housing and extends radially from the
cylindrical wall to the side wall of the housing adjacent the
discharge outlet opening.
[0010] The cylindrical wall and radial wall of the inlet guide
direct combustion gases from the inlet opening into the blower
housing interior where the gases can be compressed by the impeller
and expelled through the discharge outlet opening to exhaust piping
that is vented to the atmosphere. The cylindrical wall and radial
wall isolate the vacuum inlet pressure drawing a flow of air into
the housing, from the increased outlet pressure forcing the flow of
combustion exhaust gases from the housing. The radial wall and
cylindrical wall thereby prevent leakage and recirculation of
combustion exhaust gases from the outlet side of the blower housing
to the inlet side of the blower housing. Thus, the blower housing
of the present invention eliminates inefficiencies of conventional
volute blower housings with a simplified, inexpensive baffle
construction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Further objectives and features of the present invention are
set forth in the following detailed description of the preferred
embodiment of the invention and in the drawing figures,
wherein:
[0012] FIG. 1 is a top plan view of a blower housing of the present
invention;
[0013] FIG. 2 is a cross-sectional view of the blower housing of
FIG. 1 taken along line 2-2 of FIG. 1;
[0014] FIG. 3 is a top cross-sectional view of the blower housing
of FIG. 1 taken along line 3-3 of FIG. 2; and
[0015] FIG. 4 is a top plan view of an interior of the blower
housing of FIG. 1 with the impeller removed therefrom.
[0016] Corresponding reference characters indicate corresponding
parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0017] In the foregoing discussion, the terms "top", "bottom", and
"side" will be used for illustrative purposes to describe the parts
of the blower and blower housing of the present invention as those
parts appear and are oriented in the drawing figures. It is not
intended to limit the invention in any way through use of these
terms.
[0018] FIGS. 1 and 2 show the blower of the present invention,
generally indicated at reference character 20. The blower 20
includes a housing 22 with a top end wall 24 and an opposite facing
bottom end wall 26. The top end wall 24 has opposite interior and
exterior surfaces 28,30 and the bottom end wall 26 has opposite
interior and exterior surfaces 32,34 where each of the top and
bottom end walls 24,26 are bounded by respective spiral shaped
peripheral edges 36,38. The interior surfaces of the top and bottom
walls 28,32 face each other and a volute shaped side wall 40
extends between the top and bottom end walls 24,26 at the top and
bottom end wall peripheral edges 36,38. Together the top and bottom
end walls 24,26 and the side wall 40 define a hollow interior 42
for the blower housing 22. Preferably, the blower housing 22 is
constructed of a high-temperature resistant plastic material
capable of being manufactured in high speed injection molding
processes, although other materials, such as sheet metal, may also
be used.
[0019] The blower housing hollow interior 42 is adapted to receive
an impeller 44 for rotation within the blower housing interior 42.
Preferably, the impeller 44 has a back plate 46 with an outer
diameter D.sub.1 and vertical impeller blades or vanes 50 arranged
in a ring around the impeller outer diameter D.sub.1. The impeller
vanes 50 depend from the impeller back plate 46 and are supported
by a support ring 52 opposite the back plate 46. The support ring
52 also has an outer diameter dimension of D.sub.1 and has a radial
width dimension that corresponds to the radial width dimensions of
the impeller vanes 50. This leaves a large opening 53 through the
support ring 52 that provides access to the impeller interior, as
is conventional in impeller construction.
[0020] The blower housing bottom end wall 26 is provided with a
vacuum inlet opening 54 therethrough that is spaced from the
peripheral edge 38 of the bottom end wall. The vacuum inlet opening
54 is concentric with the impeller 44 and is adjacent the impeller
opening 53. Rotation of the impeller 44 draws gases into the blower
housing interior 42 through the inlet opening 54. Preferably, the
inlet opening 54 is circular with a center axis A-A and the
impeller 44 is aligned coaxially with the inlet opening center axis
A-A and rotates about the inlet opening center axis A-A. Although,
the drawing figures show the inlet opening 54 with a generally
circular cross section, the inlet opening 54 may have another shape
so as to be compatible with the furnace on which the blower is
installed.
[0021] The blower housing 22 includes an outlet channel 60 formed
by a semicylindrical outer wall 62 and a semicylindrical inner wall
64. The outer wall 62 projects tangentially from both of the top
and bottom end wall peripheral edges 36,38 and is an extension of
the side wall 40. The inner wall 64 is positioned opposite the
outer wall 62 and merges with the side wall 40 and the top and
bottom wall peripheral edges 36,38 between respective top and
bottom "U"-shaped transitions 66,68. The spiral wound side wall 40
expands radially outwardly as it extends from the "U"-shaped
transitions 66,68 at an inlet region 70 of the blower housing 22 to
the outlet channel outer wall 62. The outlet channel outer wall 62
merges with the side wall 40 at the outermost expansion of the side
wall 40, and the outlet channel inner wall 64 connects to the side
wall 40 at the "U"-shaped transitions 66,68. Rotation of the
impeller 44 in a counterclockwise direction as viewed in FIG. 3
creates a vacuum that draws exhaust gases through the inlet opening
54 and into the housing interior 42 and compresses the gases in the
housing interior 42 before forcing the pressurized gases from the
blower housing through the outlet channel 60 and its outlet
discharge opening 72.
[0022] Preferably, the blower housing 22 is formed as two pieces
which are interlocked together to enclose and seal the blower
housing hollow interior 42. As shown in the Figures, the blower
housing 22 of the present invention is formed with a top piece 80
and matching bottom piece 82 that assemble together to form an
integral unit of the blower housing 22. In this arrangement, the
top piece 80 preferably includes the top end wall 24, a portion of
the side wall 40, and a portion of the outlet channel 60.
Similarly, the bottom piece 82 includes the bottom end wall 26, a
portion of the side wall 40, and a portion of the outlet channel
60. As shown in the Figures, the bottom piece 82 is formed with a
sealing lip 84 and the top piece 80 is formed with a matching
sealing groove 86 where the lip 84 is received in the groove 86 to
lock the top and bottom pieces 80,82 together. To maintain the
sealed blower housing interior 42 at the interface of the top and
bottom pieces 80,82, matching engagement pads 88 are provided. The
engagement pads 88 are circumferentialy spaced about the side wall
and extend outward from the side wall 40. Each of the engagement
pads 88 has a fastener hole 90 therethrough and a mechanical
fastener (not shown) is directed through the hole 90 to secure the
top and bottom pieces 80,82 together. Other means may be employed
to secure the top and bottom pieces together, for example
adhesives.
[0023] In the preferred embodiment of the invention, the top end
wall 24 is provided with a plurality of screw connections 92 that
allow a blower motor (not shown) to be secured to the blower
housing 22. The top end wall 24 is also formed with a blower motor
shaft hole 94. A blower motor shaft 96 extends from the blower
motor (not shown) through the blower motor shaft hole 94 into the
blower housing hollow interior 42 where it is coupled to the
impeller back plate 46. Preferably, the shaft hole 94 and the inlet
opening 54 are coaxially aligned along the inlet opening center
axis A-A. In this configuration, the bottom end wall 26 is formed
with the inlet opening 54 axially opposite the blower motor shaft
hole 94.
[0024] In order to minimize piping connections in the furnace, the
blower housing inlet opening 54 is preferably directly aligned with
an outlet of the furnace, or furnace bonnet (not shown), where the
combustion gases exit the heat exchanger (not shown) of the
furnace. In order to secure the blower housing 22 to the furnace
bonnet (not shown), mounting pads 98 are preferably provided on the
coterminous edge of the side wall 40 and the bottom end wall 26 and
are circumferentialy spaced about the spiral wound side wall 40
extending outward from the side wall 40.
[0025] As shown in the Figures, the inlet opening 54 has a
peripheral edge 100 and a cylindrical wall 102 extends around the
inlet opening center axis A-A and projects axially into the blower
housing interior 42 at the inlet opening peripheral edge 100.
Although the drawing figures show the cylindrical wall 102 as
having a generally circular cross-section that is consistent with
the geometry of the inlet opening 54, the cylindrical wall 102 may
have a shape other than a cylinder so as to match the general shape
of the inlet opening 54 and form a smooth transition therewith. The
cylindrical wall 102 has a smooth interior bore 104 with an inner
diameter dimension D.sub.2. In the preferred embodiment, the inner
diameter dimension D.sub.2 is less than half of an interior
dimension of the housing measured across the housing from the
"U"-shaped transition 68, across the inlet open center axis A-A to
the opposite side of the housing 22. The bore 104 is preferably
aligned concentric with the impeller 44. The cylindrical wall 102
has an outer surface 108 with an outer diameter dimension D.sub.3.
To provide radial support for the cylindrical wall 102, a support
wall 112 is formed around the outer surface 108 of the cylindrical
wall 102 and the bottom end wall interior surface 32. The support
wall 112 has a smaller axial height dimension than the cylindrical
wall 102 so that the support wall 112 does not interfere with the
flow of exhaust gases drawn into the blower housing interior 42
through the bore 104 of the cylindrical wall 102.
[0026] The bottom end wall 26 of the blower housing 22 is provided
with a radial wall 114 that projects axially from the bottom end
wall interior surface 32 and extends radially from the cylindrical
wall outer surface 108 to the "U"-shaped transition 68. Preferably,
the radial wall 114 is a planar member that projects
perpendicularly from the bottom wall interior surface 32 so as to
simplify the shape of the housing bottom piece 82 and to allow
simplified molding of the bottom end wall 26 and the radial wall
114. Preferably, the radial wall 114 defines a plane that also
includes the inlet opening center axis A-A. In this arrangement,
the radial wall 114 connects to the side wall 40 at the position in
the blower housing interior where the radial clearance between the
impeller 44 and the side wall 40 is the smallest. At this position,
the potential for fluid flow crossing from the outlet channel 60 of
the blower housing to the inlet region 70 of the blower housing 22
is the highest. By aligning the radial wall in a plane that
includes the inlet opening center axis, the flow of exhaust gases
exiting the blower housing is directed by the radial wall 114
toward the discharge outlet opening 72. In addition, the angles
between the radial wall 114 and the outer surface 108 of the
cylindrical wall 102 are both equal and are maximized, which
simplifies the removal of the mold (not shown) from the molded
radial wall 114 and cylindrical wall 102 of the housing.
Preferably, the axial height of the cylindrical wall 102 and the
radial wall 114 are the same so as to minimize turbulence within
the blower housing interior 42 and also to simplify molding and the
removal of the mold from the walls. For example, if the cylindrical
wall were higher than the radial wall it may have a tendency to
stick in the mold making removal of the blower housing difficult.
The axial height of the radial wall 114 is such that when the
impeller 44 is installed in the blower housing interior 42, the
impeller support ring 52 has an axial clearance above the radial
wall 114 that permits free rotation of the impeller 44 in the
blower housing hollow interior 42. This also axially spaces the
impeller 44 from the cylindrical wall 102. Preferably, the housing
bottom piece 82, cylindrical wall 102, support wall 112, and radial
wall 114 are integrally formed. More preferably, the bottom piece
82, cylindrical wall 102, support wall 112, and radial wall 114 are
formed monolithically by molding them as one piece.
[0027] During operation of the blower 20, exhaust and combustion
gases are drawn through the inlet opening 54 and through the
cylindrical wall bore 104 into the blower housing hollow interior
42 by a vacuum created in the impeller interior by rotation of the
impeller 44. As the inlet opening and cylindrical wall inner
diameter D.sub.2 is smaller than the impeller outer diameter
D.sub.1, the combustion gases are expanded radially outward in the
blower housing interior 42 as they flow from the cylindrical wall
102 through the vanes 50 to the outer diameter D.sub.1 of the
impeller. By sizing the inlet opening 54 and cylindrical wall inner
diameter D.sub.2 with a smaller dimension than the impeller outer
diameter D.sub.1, a stronger vacuum drawing pressure is formed in
the blower housing 22. This enables a blower 20 with a standard
impeller to develop higher flow rates and increased outlet
pressures. Preferably, the impeller 44 used in the blower 20 has an
outer diameter dimension D.sub.1 that is at least twice as large as
the inner diameter D.sub.2 of the cylindrical wall 102 and
preferably is between 43/4 inches and 5 inches and has an axial
height between 1.700 inches and 1.900 inches, and, preferably, the
cylindrical wall outer diameter dimension D.sub.3 is between 17/8
inches and 21/8 inches, and with a tube wall dimension of between
{fraction (7/32)} inches and {fraction (9/32)} inches, the bore
inner diameter D.sub.2 is roughly 15/8 inches to 2 inches. The
inventor has found that the sizes and dimensions stated herein
provide the most effective combination for maximizing the flow
characteristics of the blower. As will be apparent to those skilled
in the art, other sizes and dimensions of components of the blower
may also be used in accordance with the general principles of the
invention.
[0028] The rotation of the impeller 44 compresses the combustion
exhaust gases as it forces a flow of the gases counterclockwise
around the blower housing interior 42 as viewed in FIG. 3 and
expels the combustion exhaust gases through the outlet channel 60
and the outlet discharge opening 72. The radial wall 114 provided
in the bottom end wall 26 prevents combustion exhaust gases from
recirculating from the outlet channel 60 across the area adjacent
the "U"-shaped transitions 66,68 to the inlet region 70 of the
blower housing 22. This creates a more efficient flow within the
blower housing interior 42 and enables a blower 20 with a set
impeller diameter and a set impeller rotational speed to develop
increased output pressure and flow rates. In order to minimize
recirculation of exhaust gases from the outlet channel 60 back
toward the blower housing inlet region 70 along the top wall end
24, the top end wall 24 is preferably formed flat in a plane
perpendicular to the inlet opening center axis A-A and the impeller
back plate 46 is positioned with minimal axial clearance between it
and the top end wall 24.
[0029] As will be apparent to those skilled in the art, the inlet
guide, including the cylindrical wall 102 and the radial wall 104
described herein, is of a simple geometry that facilitates the
manufacturing of the blower housing 22. Thus, the blower housing 22
may be formed from simple molding processes that do not require
sophisticated tooling with intricate surfaces or tooling that
requires die inserts. Moreover, the inlet guide described herein
may also be retrofitted into existing blower housings by securing
the cylindrical wall 102 and radial wall 114 to the housing
interior at the inlet opening 54. For example, a blower housing may
be retrofit with the inlet guide described herein by securing a
section of tubing, such as a PVC pipe, within the existing inlet
opening of the blower housing so that it extends a short distance
into the blower housing interior. The pipe section may also be
attached to the interior surface of the bottom end wall such that
the bore of the pipe section matches the inlet opening. A section
of flat stock may then be used to form the radial wall in the
manner described previously. In addition to forming the blower
housing from a plastic material, the blower housing may also be
constructed from sheet metal in which case the inlet guide may be
similarly constructed and joined to the blower housing using metal
joining techniques common in the art, i.e. welding, brazing, clinch
joints, mechanical fasteners, adhesives.
[0030] While the present invention has been described by reference
to specific embodiments, it should be understood that modifications
and variations of the invention may be constructed without
departing from the scope of the invention as defined by the
following claims.
* * * * *