Rotary kinetic fluid motors or pumps – Working fluid passage or distributing means associated with... – Casing having tangential inlet or outlet
Reexamination Certificate
2000-08-31
2003-01-28
Ryznic, John E. (Department: 3745)
Rotary kinetic fluid motors or pumps
Working fluid passage or distributing means associated with...
Casing having tangential inlet or outlet
C415S214100
Reexamination Certificate
active
06511288
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The invention relates to blowers for high efficiency furnaces for drawing combustion gases into the furnace and propelling the products of combustion into the exhaust pipe to be vented to atmosphere. More specifically, the invention relates to the construction of the blower housing.
(2) Description of the Related Art
Blowers to which the present invention is directed are common in the art. The blower is used on high efficiency furnaces (e.g. 90% efficiency) to draw combustion air into the furnace from outside the home. Generally, these blowers are located downstream of a combustion chamber or combustion tubes in the furnace, depending upon the style of furnace. Combustion air is drawn into the combustion chamber or combustion tubes, mixed with fuel, and ignited to generate heat for the furnace. The exhaust gases are then drawn into the suction of the blower and discharged from the blower to an exhaust pipe that vents to outside atmosphere.
FIG. 1A
shows a blower
20
of the prior art arranged on a blower mounting surface
21
of a furnace
23
. The blower
20
includes a blower motor
47
and a blower housing
24
. In
FIG. 1A
, the blower motor has been removed from its center mount
26
on top of the blower housing
24
to show greater detail of the blower housing
24
. The blower housing
24
has a side wall
28
extending between a top piece
30
and a bottom piece
32
. Locator surfaces
33
A,
33
B are provided on the top and bottom pieces
30
,
32
to align the top and bottom pieces
30
,
32
. The locator surfaces
33
A,
33
B also form a seal between the top and bottom pieces
30
,
32
to contain exhaust gases within the blower housing
24
. The top piece
30
is molded with the center mount
26
recessed to receive the blower motor
47
. The side wall
28
, top piece
30
, and bottom piece
32
form a volute
34
for the blower housing
24
. When the blower
20
is energized, an impeller (not shown), operably connected to a shaft of the blower motor , rotates in the volute
34
to draw exhaust gases through an inlet hole
35
in the center of the bottom piece
32
and to compress gases in the volute
34
. The pressurized exhaust gases are directed into a discharge pipe
36
that extends outward and away from the blower
20
and the furnace
23
. Mounting feet
38
for attaching the blower
20
to the blower mounting surface
21
of the furnace
23
are provided on the side wall
28
of the blower housing
24
.
FIG. 1B
shows the blower
20
arranged on the blower mounting surface
21
in the furnace
23
. The blower housing
24
is positioned to allow the impeller (not shown) to draw exhaust gases directly from the combustion chamber or combustion tubes (not shown) into the blower housing
24
. The discharge pipe
36
is coupled to an exhaust pipe
39
using a gasket
40
to vent the exhaust gases to atmosphere. The top piece
30
is attached to the blower mounting surface
21
using mechanical fasteners
41
through holes
42
on the mounting feet
38
. The mechanical fasteners
41
have a screw head driving end
43
and an opposite driven end
44
spaced from the driving end
43
by a shaft
45
. The screw head driving end
43
engages a seating surface
46
on the mounting foot
38
and holds the top piece
30
onto the blower mounting surface
21
. The bottom piece
32
is preferably held in position between the top piece
30
and the blower mounting surface
21
by compression from the mechanical fasteners
41
.
Typically, the impeller rotates at a high rate of speed to generate sufficient air flow into the combustion chamber and combustion tubes and to draw the exhaust gases out into the exhaust pipe
39
. As shown in
FIG. 1B
, the blower motor
47
is positioned directly atop of the blower housing
24
and the shaft (not shown) of the blower motor
47
is directly coupled to the impeller (not shown) in the blower housing
24
. The high speed rotation of the impeller and the motor
47
tends to create noise and other vibrations that are transferred directly into the blower housing
24
. As shown in
FIG. 1B
, the blower
20
is directly mounted onto the blower mounting surface
21
of the furnace
23
. Therefore, noise and vibrations are transmitted directly to the blower mounting surface
21
in the furnace
23
. This vibration results in unwanted noise being transmitted into the associated structures of the furnace
23
such as ducting where the noise can be transmitted throughout the house. The vibration also contributes to a decreased life span of the blower
20
.
In the prior art to combat these problems, the installation of the blower housing onto the furnace mounting surface generally involved installing cushioning mounts
48
and other vibration absorbing gaskets between the blower housing
24
and the blower mounting surface
21
. This technique complicates installation and causes a small air gap between the blower housing and the blower mounting surface. Often, the impeller or motor shaft must be dynamically balanced to reduce vibration; however, this process adds manufacturing cost.
What is needed to overcome the disadvantages of the prior art is to form a blower housing which has sound dampening qualities integrally formed in the housing to reduce noise and vibration transmitted from the motor and impeller into the blower mounting surface. Such a blower housing would have the vibration absorbing material integrally formed in the housing so that gaskets and other additional cushioning devices are not needed. Moreover, such a blower housing needs to be sufficiently sturdy to withstand high temperature exhaust gases passing through it.
SUMMARY OF THE INVENTION
In order to overcome the disadvantages of the prior art, the blower of the present invention includes a blower housing having a resilient bottom piece and a rigid top piece covering over the bottom piece to enclose an interior of the blower housing. The bottom piece of the blower housing is preferably cylindrically shaped and directly abuts the exterior mounting surface of the furnace with cushioned mounting flanges provided. The top piece of the blower housing is secured to the bottom piece and also provides the support for mounting the blower motor as explained below.
The bottom piece of the blower housing may be made from a vibration dampening material. Preferably, materials such as sanoprene and viram are suitable for dampening and attenuating vibrations and withstanding the heat from the products of combustion which flow through the blower housing. The top piece of the blower housing may be made from a material such as polypropylene to provide a rigid mount for the blower motor and with what may preferably be integrally formed depending mounting legs, the rigid mount for the motor extends to the furnace housing as explained below.
The top piece of the blower housing includes an annular central lower support portion for supporting the blower motor and an annular upper portion extending above and around the lower portion. The upper portion of the top piece of the blower housing has an outer peripheral edge and preferably a plurality of lugs extending outwardly beyond the outer peripheral edge. The bottom piece of the blower housing has preferably a plurality of flanges that align with the lugs when the blower housing is assembled. The flange interlocks with the lug to detachably engage the top piece to the bottom piece. The top piece, side wall and bottom piece form a volute for the blower housing.
The lugs on the top piece have a lug hole to receive a mechanical fastener such as a screw or bolt and provide the surface against which the mechanical fastener is snugged as it is tightened to mount the blower. The flanges on the bottom piece preferably have flange holes that receive the mechanical fasteners therethrough as the mechanical fasteners join the top piece to the blower mounting surface of the furnace. The mechanical fasteners preferably attach the blower housing to a blower mounting surface of the furnace such that the blower housin
Jakel Incorporated
Ryznic John E.
Thompson & Coburn LLP
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