U.S. patent application number 11/058958 was filed with the patent office on 2005-08-18 for gas delivery system with pre-mix blower.
Invention is credited to Garrett, Michael K., Pueppke, Darrell E..
Application Number | 20050178344 11/058958 |
Document ID | / |
Family ID | 34886137 |
Filed Date | 2005-08-18 |
United States Patent
Application |
20050178344 |
Kind Code |
A1 |
Garrett, Michael K. ; et
al. |
August 18, 2005 |
Gas delivery system with pre-mix blower
Abstract
A gas delivery system for an appliance, such as a water heater,
including a gas control valve and a blower housing assembly which
are mounted to the water heater proximate one another. The blower
housing assembly includes a motor for driving an impeller within
the blower housing, and an outlet of the blower housing is
connected to the gas burner assembly of the water heater. A gas
supply conduit extends from the control valve into the blower
housing, and the outlet of the gas supply conduit is disposed
within the blower housing interior near the blower housing inlet
and the central portion of the impeller. In operation, rotation of
the impeller draws a flow of air through the blower housing.
Concurrently, gas is supplied through the gas supply conduit to the
interior of the blower housing near the impeller, and the gas is
mixed with the flow of air to form an air/gas mixture which is
supplied through the outlet of the blower housing to the gas burner
for combustion. In this manner, the gas is pre-mixed with air
within the blower housing before being supplied to the burner
assembly, and wherein combustion of the air/gas mixture results in
a cleaner combustion with reduced nitrous oxide emissions.
Inventors: |
Garrett, Michael K.;
(Cassville, MO) ; Pueppke, Darrell E.; (Rocky
Comfort, MO) |
Correspondence
Address: |
BAKER & DANIELS LLP
111 E. WAYNE STREET
SUITE 800
FORT WAYNE
IN
46802
US
|
Family ID: |
34886137 |
Appl. No.: |
11/058958 |
Filed: |
February 16, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60545340 |
Feb 17, 2004 |
|
|
|
Current U.S.
Class: |
122/17.1 ;
126/91A |
Current CPC
Class: |
F23D 14/64 20130101;
F23D 14/62 20130101; F23D 14/36 20130101 |
Class at
Publication: |
122/017.1 ;
126/091.00A |
International
Class: |
F24H 001/00; F24H
003/02; F23C 005/00 |
Claims
What is claimed is:
1. A gas supply assembly for supplying an air/gas mixture to the
burner assembly of a water heater, comprising: a blower housing
assembly, comprising: a blower housing having an inlet, and an
outlet in fluid communication with the gas burner assembly; a motor
having a rotatable output shaft; and an impeller coupled to said
output shaft and disposed within said blower housing; and a gas
supply conduit fluidly communicating a source of gas to said blower
housing, whereby rotation of said impeller draws air into said
blower housing through said inlet, and gas supplied through said
gas supply conduit is mixed with the air within said blower housing
to form an air/gas mixture which is supplied to the gas burner
assembly through said blower housing outlet.
2. The gas supply assembly of claim 1, wherein said gas supply
conduit includes an outlet end disposed adjacent said inlet of said
blower housing.
3. The gas supply assembly of claim 1, wherein said gas supply
conduit includes an outlet end aligned substantially 90.degree.
with respect to a direction of air flow into said blower housing
inlet.
4. The gas supply assembly of claim 1, wherein said blower housing
includes a bore, at least a portion of said gas supply conduit
received within said bore.
5. The gas supply assembly of claim 1, further comprising a control
valve in fluid communication with the gas source, said control
valve selectively controlling gas flow from the gas source through
said gas supply conduit.
6. The gas supply assembly of claim 5, wherein said gas supply
conduit comprises: an inlet end connected to said control valve;
and an outlet end connected to said blower housing.
7. The gas supply assembly of claim 6, wherein at least one of said
inlet and said outlet ends of said gas supply conduit is connected
to said control valve and said blower housing via a compression
fitting.
8. A gas supply assembly for supplying an air/gas mixture to the
burner assembly of a water heater, comprising: a blower housing
assembly, comprising: a blower housing having an inlet, and an
outlet in fluid communication with the gas burner assembly; a motor
having a rotatable output shaft; and an impeller coupled to said
output shaft and disposed within said blower housing; and a control
valve fluidly communicating a source of gas to said blower housing,
whereby rotation of said impeller draws air into said blower
housing through said inlet, and gas supplied through said control
valve is mixed with the air within said blower housing to form an
air/gas mixture which is supplied to the gas burner assembly
through said blower housing outlet.
9. The gas supply assembly of claim 8, further comprising a gas
supply conduit connecting said control valve and said blower
housing.
10. The gas supply assembly of claim 9, wherein said gas supply
conduit includes an outlet end disposed adjacent said inlet of said
blower housing.
11. The gas supply assembly of claim 9, wherein said gas supply
conduit includes an outlet end aligned substantially 90.degree.
with respect to a direction of air flow into said blower housing
inlet.
12. The gas supply assembly of claim 9, wherein at least one of an
inlet and an outlet end of said gas supply conduit is connected to
said control valve and said blower housing via a compression
fitting.
13. A method of operating a gas supply assembly for a water heater,
comprising the steps of: rotating an impeller within a blower
housing to induce an air flow through the blower housing; supplying
gas from a gas source into the blower housing; mixing the gas with
the air flow within the blower housing to form an air/gas mixture;
and supplying the air/gas mixture to a burner assembly of the water
heater.
14. The method of claim 13, wherein said supplying step further
comprises supplying gas from a gas source into the blower housing
through a gas supply conduit fluidly connecting the gas source to
the blower housing.
15. The method of claim 13, wherein said supplying step further
comprises supplying gas from a gas source into the blower housing
through a control valve.
16. The method of claim 13, wherein said supplying step further
comprises supplying gas from a gas source into the blower housing
at a location adjacent an inlet of the blower housing.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit under Title 35, U.S.C.
.sctn. 119(e) of U.S. Provisional Patent Application Ser. No.
60/545,340, entitled GAS DELIVERY SYSTEM WITH PRE-MIX BLOWER, filed
on Feb. 17, 2004.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to gas delivery systems for
gas-operated appliances, and in particular, relates to a gas
delivery system for the gas burner assembly of a water heater.
[0004] 2. Description of the Related Art
[0005] Gas water heaters are used in residential and commercial
applications to heat cold water from a water source, and to store
heated water for demand-based supply to one or more water taps or
other appliances. Gas water heaters generally include an insulated
holding tank having a cold water inlet, usually located near the
top of the tank, which supplies cold water to the lower portion of
the tank through a dip tube. A hot water outlet, also typically
located near the top of the tank, supplies heated water from the
upper portion of the tank to one or more use locations through
suitable conduits.
[0006] A control valve, typically mounted near the lower outside
portion of the tank of the water heater, is connected to a gas
supply. The control valve includes a thermostat which detects the
temperature of the water in the tank, and regulates gas delivery
from the gas source to one or more gas burners which are located in
a burner chamber beneath the tank. The burners are ignited by a
pilot light or by a spark ignition system, for example. Gas is
supplied by the control valve directly to the ignited burner for
combustion in the presence of air, which generates heat for heating
the water in the lower portion of the tank. The heated water
generally rises to the upper portion of the tank, such that cold
water supplied through the end of the dip tube is heated in the
lower portion of the tank and thereafter rises to the upper portion
of the tank.
[0007] A vent chimney vents exhaust gases from the burner chamber
through suitable conduits to the atmosphere. Some water heaters
also include a blower, usually located near the top portion of the
tank, for assisting evacuation of the exhaust gases from the burner
chamber through the chimney.
[0008] A problem with the foregoing gas delivery systems is that
combustion of the gas by the burner, in which the gas is supplied
directly to the burner, tends to produce a relatively large amount
of nitrous oxide (NO.sub.x) emissions.
[0009] What is needed is a gas delivery system for appliances, such
as water heaters, which is effective to reduce nitrous oxide
emissions.
SUMMARY OF THE INVENTION
[0010] The present invention provides a gas delivery system for an
appliance, such as a water heater, including a gas control valve
and a blower housing assembly which are mounted to the water heater
proximate one another. The blower housing assembly includes a motor
for driving an impeller within the blower housing, and an outlet of
the blower housing is connected to the gas burner assembly of the
water heater. A gas supply conduit extends from the control valve
into the blower housing, and the outlet of the gas supply conduit
is disposed within the blower housing interior near the blower
housing inlet and the central portion of the impeller. In
operation, rotation of the impeller draws a flow of air through the
blower housing. Concurrently, gas is supplied through the gas
supply conduit to the interior of the blower housing near the
impeller, and the gas is mixed with the flow of air to form an
air/gas mixture which is supplied through the outlet of the blower
housing to the gas burner for combustion. In this manner, the gas
is pre-mixed with air within the blower housing before being
supplied to the burner assembly, and wherein combustion of the
air/gas mixture results in a cleaner combustion with reduced
nitrous oxide emissions.
[0011] Advantageously, the present inventors have found that
supplying a mixture of air and gas to the burner for combustion,
rather than supplying gas directly to the burner as in known gas
burner systems currently used in water heaters, results in a
cleaner combustion with reduced nitrous oxide emissions.
Additionally, the present gas delivery system is easily assembled
to the water heater, thus reducing the overall cost of the water
heater.
[0012] In one embodiment, the gas delivery system is assembled to a
water heater as follows. First, the gas control valve is mounted to
the water heater. Then, the blower housing assembly is mounted to
the water heater near the gas control valve. The gas supply conduit
is then extended from the blower housing for connection to a
compression fitting at the outlet of the control valve. Thereafter,
the compression fitting at the control valve outlet is tightened to
secure the gas supply conduit to the gas control valve, followed by
tightening a compression fitting at the gas inlet of the blower
housing to secure the gas supply conduit to the blower housing.
[0013] In one form thereof, the present invention provides a gas
supply assembly for supplying an air/gas mixture to the burner
assembly of a water heater, including a blower housing assembly,
including a blower housing having an inlet, and an outlet in fluid
communication with the gas burner assembly; a motor having a
rotatable output shaft; and an impeller coupled to the output shaft
and disposed within the blower housing; and a gas supply conduit
fluidly communicating a source of gas to the blower housing,
whereby rotation of the impeller draws air into the blower housing
through the inlet, and gas supplied through the gas supply conduit
is mixed with the air within the blower housing to form an air/gas
mixture which is supplied to the gas burner assembly through the
blower housing outlet.
[0014] In another form thereof, the present invention provides a
gas supply assembly for supplying an air/gas mixture to the burner
assembly of a water heater, including a blower housing assembly,
including a blower housing having an inlet, and an outlet in fluid
communication with the gas burner assembly; a motor having a
rotatable output shaft; and an impeller coupled to the output shaft
and disposed within the blower housing; and a control valve fluidly
communicating a source of gas to the blower housing, whereby
rotation of the impeller draws air into the blower housing through
the inlet, and gas supplied through the control valve is mixed with
the air within the blower housing to form an air/gas mixture which
is supplied to the gas burner assembly through the blower housing
outlet.
[0015] In a further form thereof, the present invention provides a
method of operating a gas supply assembly for a water heater,
including the steps of rotating an impeller within a blower housing
to induce an air flow through the blower housing; supplying gas
from a gas source into the blower housing; mixing the gas with the
air flow within the blower housing to form an air/gas mixture; and
supplying the air/gas mixture to a burner assembly of the water
heater.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The above-mentioned and other features and advantages of
this invention, and the manner of attaining them, will become more
apparent and the invention itself will be better understood by
reference to the following description of an embodiment of the
invention taken in conjunction with the accompanying drawings,
wherein:
[0017] FIG. 1 is a perspective view of the lower portion of a water
heater having a gas delivery system in accordance with the present
invention, including a control valve, blower housing, and gas
supply conduit;
[0018] FIG. 2 is a front view of the control valve, blower housing,
and gas supply conduit of FIG. 1;
[0019] FIG. 3 is a section al view taken along line 3-3 of FIG.
2;
[0020] FIG. 4 is an enlarged fragmentary view of a portion of FIG.
3, showing a compression fitting;
[0021] FIG. 5 is a perspective view of the blower housing assembly
and gas supply conduit, viewed from above, in which the impeller is
visible within the blower housing; and
[0022] FIG. 6 is a perspective view of the blower housing assembly
and gas supply conduit, viewed from below, in which a portion of
the impeller is visible within the blower housing.
[0023] Corresponding reference characters indicate corresponding
parts throughout the several views. The exemplification set out
herein illustrates one preferred embodiment of the invention, in
one form, and such exemplification is not to be construed as
limiting the scope of the invention any manner.
DETAILED DESCRIPTION
[0024] Referring to FIG. 1, the lower portion of a water heater 20
is shown, which generally includes an insulated holding tank 22,
and a gas burner assembly 24 disposed in the lower portion of water
heater 20 generally beneath holding tank 22. Gas burner assembly 24
includes a gas manifold 26 and one or more burners (not shown)
having spark or hot surface igniters, or example. Water heater 20
additionally includes other known features common to presently
manufactured water heaters, such as those discussed above, which do
not pertain to the present invention and therefore are not shown
and described herein in detail.
[0025] Referring to FIGS. 1-3, 5, and 6, the gas delivery system or
gas supply assembly 38 of the present invention includes a gas
control valve 40 mounted to water heater 20 in a suitable manner,
such as with screw fasteners, for example. Control valve 40
includes valve body 42 and, as shown in FIGS. 2 and 3, gas inlet 44
and gas outlet 46. Gas inlet 44 is connected to a gas supply in a
conventional manner, such as to the gas supply in a residential
home, for example. Control valve 40 further includes a thermostat
with temperature control (not shown) for detecting the temperature
of the water in tank 22 of water heater 20, and a control mechanism
(not shown) for regulating the supply of gas to the gas burner
assembly from the gas source. Control valve 40 may be a SV9560 or
SV9570 or similar water heater control, available from Honeywell,
Inc., Minneapolis, Minn., or a 2000 WIPER/WDER or similar gas
heating control, available from RobertShaw Controls Company, Long
Beach, Calif., for example.
[0026] Blower housing assembly 50 generally includes blower housing
52, electric motor 54, and impeller 56. Blower housing 52 may
include features similar to the blower housings which are disclosed
in U.S. patent application Ser. No. 10/934,004, entitled DRAFT
INDUCER BLOWER WITH Z-AXIS VOLUTE, filed on Sep. 3, 2004; U.S.
patent application Ser. No. 10/934,070, entitled LOBED JOINT DRAFT
INDUCER BLOWER, filed on Sep. 3, 2004; and U.S. Pat. No. 5,954,476
to Stewart et al., each assigned to the assignee of the present
invention, the disclosures of which are expressly incorporated
therein by reference. Motor 54 may be, for example, any of a number
of existing electric motors manufactured by Fasco, Inc. of
Cassville, Mo.
[0027] Blower housing 52 is mounted to water heater 20 with
suitable fasteners which extend through mounting bosses 57 (FIG. 2)
into water heater 20 or a suitable bracket (not shown) attached to
water heater 20. Blower housing 52 may be made of stamped and/or
formed sheet metal components, or alternatively, may be formed of
molded plastic components, and generally includes first housing
section 58 connected to second housing section 60 in a suitable
manner, such as via a tongue-and-groove snap fit connection of the
type disclosed in the above-incorporated U.S. Pat. No. 5,954,476 to
Stewart et al. First housing section 58 is disposed adjacent water
heater 20, and includes a circular inlet opening 62. Motor 54 is
mounted to second housing section 60, and includes output shaft 64
extending through a hole in second housing section 60. Motor 54 is
electrically connected to control valve 40, and the operation of
motor 54 is controlled by control valve 40.
[0028] Impeller 56 is mounted to the end of output shaft 64, and is
rotatably driven by motor 54 within blower housing 52 to draw air
into blower housing 52 through inlet opening 62 and to discharge
the air through outlet 66 of blower housing 52. Outlet 66 of blower
housing 52 is connected to manifold 26 of gas burner assembly 24
beneath tank 22 of water heater 20, and gas burner assembly 24
includes one or more gas burners (not shown) for burning an air/gas
mixture which is supplied to the gas burner assembly in the manner
described below.
[0029] Referring additionally to FIG. 4, first housing section 58
of blower housing 52 additionally includes gas inlet 68 including
threaded interior bore 70. Gas supply conduit 72 includes inlet end
74 connected to gas outlet 46 of control valve 40, and also
includes outlet end 76. In particular, gas supply conduit 72 is
connected to gas outlet 46 of control valve 40 and to blower
housing 52 by first and second compression fittings 78 and 80.
Referring to FIG. 4, each compression fitting 78 and 80 is
identical, and includes nut 82 with external threads 83 for
engagement with the internal threads 85 of gas outlet 46 of control
valve 40 and threaded bore 70 of gas inlet 68 of blower housing 52.
Compression fittings 78 and 80 each additionally include annular
ferrule 84, which is deformably and sealingly compressed about the
external surface of gas supply conduit 72 upon tightening of nut
82.
[0030] The gas delivery system 38 may be assembled to water heater
20 in the following manner, although variations in the procedure
described below will be apparent to those skilled in the art.
First, control valve 40 is mounted to water heater 20 in a suitable
manner. Blower housing assembly 50 is mounted to water heater 20
below gas valve 40 in a suitable manner, and outlet 66 of blower
housing 52 is connected to the gas burner assembly of water heater
20. During installation of blower housing assembly 50, gas supply
conduit 72 may be slidably fitted within inlet 68 of blower housing
52 in a downwardly or inwardly-shifted position, in which gas
supply conduit 72 is translated toward the interior of blower
housing 52.
[0031] Following mounting of blower housing assembly 50 to water
heater 20, gas supply conduit 72 is translated upwardly or
outwardly of blower housing 52 to engage inlet end 74 thereof with
gas outlet 46 of control valve 40. Thereafter, nut 82 of first
compression fitting 78 is tightened to secure inlet end 74 of gas
supply valve 40 to gas outlet 46 of control valve 40. Then, nut 82
of second compression fitting 80 is tightened to secure gas supply
conduit 70 to blower housing 52.
[0032] As shown in FIGS. 3 and 6, after gas supply conduit 72 has
been thus secured, outlet end 76 of gas supply conduit 72 is
disposed closely adjacent the central portion of impeller 56 and at
substantially a 90.degree. relationship to the direction of air
flow through inlet opening 62 of blower housing 52. Thus, outlet
end 76 of gas supply conduit 72 is connected to blower housing 52
adjacent inlet opening 62 of blower housing 52 in the manner
described herein. Advantageously, upon rotation of impeller 56, air
is drawn into blower housing 52 through inlet opening 62, forming a
low pressure area at inlet opening 62. Thus, when impeller 56 is
rotating, gas supplied through gas supply conduit 72 is readily and
immediately drawn into inlet opening 62. Alternatively, in other
embodiments, control valve 40 may be mounted directly to blower
housing 52, wherein the length of gas supply conduit 72 may be
reduced, or gas supply conduit 72 may be unnecessary.
[0033] In operation, when control valve 40 detects via its
thermostat that water in tank 22 of water heater 20 needs to be
heated, control valve 40 actuates motor 54 to rotate impeller 56
within blower housing 52 to draw inlet air through inlet opening 62
of blower housing 52, and to discharge the air through outlet 66 of
blower housing 52 to the gas burner assembly of water heater 20.
After a flow of air is established through blower housing 52,
control valve 40 supplies gas through gas supply conduit 72, such
that the gas exits the gas supply conduit 72 at outlet end 76. The
gas is then immediately drawn into the air stream and is intimately
mixed with the intake air within blower housing 52 to form an
air/gas mixture which is then supplied through outlet 66 of blower
housing 52 to gas burner assembly 24 of water heater 20. Control
valve 40 may control both the speed of rotation motor 54 and
impeller 56, as well as amount of gas which is supplied through gas
supply conduit 72 to portion the air/gas mixture as desired.
[0034] In this manner, blower housing 52 and impeller 54 act
similar to the carburetor of an engine to intimately and thoroughly
mix the gas with a supply of intake air to form an air/gas mixture
which is supplied to gas burner assembly of water heater 20 for
combustion. Combustion of the gas/air mixture results in a cleaner
combustion, which reduces nitrous oxide emissions over the higher
emissions observed when gas is supplied directly to the burners for
combustion, as in the burners of known water heaters.
[0035] While this invention has been described as having a
preferred design, the present invention can be further modified
within the spirit and scope of this disclosure. This application is
therefore intended to cover any variations, uses, or adaptations of
the invention using its general principles. Further, this
application is intended to cover such departures from the present
disclosure as come within known or customary practice in the art to
which this invention pertains and which fall within the limits of
the appended claims.
* * * * *