U.S. patent application number 16/863888 was filed with the patent office on 2021-11-04 for gas burner assembly.
The applicant listed for this patent is A. O. SMITH CORPORATION. Invention is credited to Billy Anthony Batey, Mark Allan Murphy, Jimmy Charles Smelcer, Trent Conor Snively.
Application Number | 20210341177 16/863888 |
Document ID | / |
Family ID | 1000004816024 |
Filed Date | 2021-11-04 |
United States Patent
Application |
20210341177 |
Kind Code |
A1 |
Smelcer; Jimmy Charles ; et
al. |
November 4, 2021 |
GAS BURNER ASSEMBLY
Abstract
An atmospheric gas water heater includes a burner assembly. The
burner assembly includes a burner having a body, and a screen
member coupled to the body. A conduit is fluidly connected to the
body. The conduit has an open end configured to receive gas and
air. The flow of gas and air from the open end through the conduit
to the body and past the screen member is defined as a downstream
direction. The screen member defines a zone of combustion. The gas
and the air is 100% premixed together upstream of the zone of
combustion. The body of the burner has a first segment extending
between a first end and a second end, and second and third segments
extending from the first segment. The second segment and the third
segment extend parallel to and spaced apart from each other to form
a U-shape.
Inventors: |
Smelcer; Jimmy Charles; (Mt.
Juliet, TN) ; Murphy; Mark Allan; (Nashville, TN)
; Snively; Trent Conor; (Nashville, TN) ; Batey;
Billy Anthony; (Watertown, TN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
A. O. SMITH CORPORATION |
Milwaukee |
WI |
US |
|
|
Family ID: |
1000004816024 |
Appl. No.: |
16/863888 |
Filed: |
April 30, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F23D 2203/1017 20130101;
F23D 2203/103 20130101; F23D 14/04 20130101; F24H 1/186 20130101;
F23Q 9/12 20130101; F24H 1/181 20130101; F23D 14/70 20130101 |
International
Class: |
F24H 1/18 20060101
F24H001/18; F23D 14/04 20060101 F23D014/04; F23D 14/70 20060101
F23D014/70; F23Q 9/12 20060101 F23Q009/12 |
Claims
1. An atmospheric gas water heater comprising: a tank containing
water to be heated; a flue assembly positioned within the tank; and
a burner assembly in fluid communication with the flue assembly,
the burner assembly including, a burner having a body, and a screen
member coupled to the body, and a conduit fluidly connected to the
body, the conduit having an open end, the open end configured to
receive gas and air, wherein a flow of the gas and the air from the
open end through the conduit to the body and past the screen member
is defined as a downstream direction, wherein the screen member
defines a zone of combustion, wherein the gas and the air is 100%
premixed together upstream of the zone of combustion, and wherein
the body of the burner has a first segment extending between a
first end and a second end, a second segment extending from the
first segment at the first end, and a third segment extending from
the first segment at the second end, the second segment and the
third segment extending parallel to and spaced apart from each
other to form a U-shape.
2. The atmospheric gas water heater of claim 1, wherein the gas is
only diluted by the air entering the burner assembly via the
conduit.
3. The atmospheric gas water heater of claim 1, further comprising
a combustion chamber configured to receive the burner assembly,
wherein all of the air entering the combustion chamber is directed
through the body of the burner and past the screen member.
4. The atmospheric gas water heater of claim 1, wherein the conduit
includes a venturi portion, and wherein the venturi portion is
positioned at the open end.
5. The atmospheric gas water heater of claim 1, wherein the conduit
is positioned between the second segment and the third segment, and
wherein the conduit is fluidly connected to the first segment.
6. The atmospheric gas water heater of claim 1, wherein the burner
assembly includes an internal chamber defined by the body and the
screen member, wherein a baffle assembly is positioned within the
internal chamber for directing the air and gas within the internal
chamber, and wherein the baffle assembly is positioned within the
first segment.
7. An atmospheric gas water heater comprising: a tank containing
water to be heated; a flue assembly positioned within the tank; and
a burner assembly in fluid communication with the flue assembly,
the burner assembly including, a burner having a body, and a screen
member coupled to the body, the body having a curved surface, and a
conduit fluidly connected to the body, the conduit having an open
end, the open end configured to receive gas and air, wherein a flow
of the gas and the air from the open end through the conduit to the
body and past the screen member is defined as a downstream
direction, wherein the screen member defines a zone of combustion,
wherein the gas and the air is 100% premixed together upstream of
the zone of combustion, wherein during operation, the burner is
configured to oscillate at a first vibration frequency, wherein
during operation, flames produced at the zone of combustion are
configured to oscillate at a second vibration frequency, and
wherein the curved surface of the body is configured to maintain
the first vibration frequency at a frequency greater than the
second vibration frequency throughout operation of the water
heater.
8. The atmospheric gas water heater of claim 7, wherein the gas is
only diluted by the air entering the burner assembly via the
conduit.
9. The atmospheric gas water heater of claim 7, further comprising
a combustion chamber configured to receive the burner assembly,
wherein all of the air entering the combustion chamber is directed
through the body of the burner and past the screen member.
10. The atmospheric gas water heater of claim 7, wherein the
conduit includes a venturi portion, and wherein the venturi portion
is positioned at the open end.
11. The atmospheric gas water heater of claim 7, wherein the first
vibration frequency is at least 1.5 times greater than the second
vibration frequency.
12. The atmospheric gas water heater of claim 7, wherein a
cross-sectional shape of the body is a C-shape to form the curved
surface.
13. The atmospheric gas water heater of claim 7, wherein the body
includes a flange, and wherein the screen member is movably coupled
to the body by the flange.
14. An atmospheric gas water heater comprising: a tank containing
water to be heated; a flue assembly positioned within the tank; a
combustion chamber fluidly connected to the flue assembly; a pilot
assembly at least partially positioned within the combustion
chamber; and a burner assembly positioned within the combustion
chamber, the burner assembly including, a burner having a body, and
a screen member coupled to the body, and a conduit fluidly
connected to the body, the conduit having an open end, the open end
configured to receive gas and air, wherein a flow of the gas and
the air from the open end through the conduit to the body and past
the screen member is defined as a downstream direction, wherein the
screen member defines a zone of combustion, wherein the gas and the
air is 100% premixed together upstream of the zone of combustion,
and wherein the pilot assembly is mounted outside of the combustion
chamber.
15. The atmospheric gas water heater of claim 14, wherein the gas
is only diluted by the air entering the burner assembly via the
conduit.
16. The atmospheric gas water heater of claim 14, wherein all of
the air entering the combustion chamber is directed through the
body of the burner and past the screen member.
17. The atmospheric gas water heater of claim 14, wherein the
conduit includes a venturi portion, and wherein the venturi portion
is positioned at the open end.
18. The atmospheric gas water heater of claim 14, wherein the
combustion chamber is defined at least partially by a wall member,
the wall member having an outer surface and an inner surface, and
wherein the pilot assembly is mounted to the outer surface and
extends through the wall member from the outer surface through the
inner surface and into the combustion chamber.
19. The atmospheric gas water heater of claim 18, wherein the
combustion chamber includes a door assembly having a door movably
mounted to a fixed portion of the wall member, the door forming a
portion of the wall member, and wherein the pilot assembly is
mounted to the door.
20. The atmospheric gas water heater of claim 14, wherein the pilot
assembly includes a pilot burner, a spark ignitor, and a
thermocouple.
Description
BACKGROUND
[0001] The present invention relates to a gas burning atmospheric
water heater, and more specifically a gas burner assembly of a gas
burning atmospheric water heater.
SUMMARY
[0002] In one embodiment, the disclosure provides an atmospheric
gas water heater including a tank containing water to be heated, a
flue assembly positioned within the tank, and a burner assembly in
fluid communication with the flue assembly. The burner assembly
includes a burner having a body, and a screen member coupled to the
body. A conduit is fluidly connected to the body. The conduit has
an open end. The open end is configured to receive gas and air. A
flow of the gas and the air from the open end through the conduit
to the body and past the screen member is defined as a downstream
direction. The screen member defines a zone of combustion. The gas
and the air is 100% premixed together upstream of the zone of
combustion. The body of the burner has a first segment extending
between a first end and a second end, a second segment extending
from the first segment at the first end, and a third segment
extending from the first segment at the second end. The second
segment and the third segment extend parallel to and spaced apart
from each other to form a U-shape.
[0003] In another embodiment, the disclosure provides an
atmospheric gas water heater including a tank containing water to
be heated, a flue assembly positioned within the tank, and a burner
assembly in fluid communication with the flue assembly. The burner
assembly includes a burner having a body, and a screen member
coupled to the body. The body has a curved surface. A conduit is
fluidly connected to the body. The conduit has an open end. The
open end is configured to receive gas and air. A flow of the gas
and the air from the open end through the conduit to the body and
past the screen member is defined as a downstream direction. The
screen member defines a zone of combustion. The gas and the air is
100% premixed together upstream of the zone of combustion. During
operation, the burner is configured to oscillate at a first
vibration frequency. During operation, flames produced at the zone
of combustion are configured to oscillate at a second vibration
frequency. The curved surface of the body is configured to maintain
the first vibration frequency at a frequency greater than the
second vibration frequency throughout operation of the water
heater.
[0004] In yet another embodiment, the disclosure provides an
atmospheric gas water heater including a tank containing water to
be heated, a flue assembly positioned within the tank, and a
combustion chamber fluidly connected to the flue assembly. A pilot
assembly is at least partially positioned within the combustion
chamber. A burner assembly is positioned within the combustion
chamber. The burner assembly includes a burner having a body, and a
screen member coupled to the body. A conduit is fluidly connected
to the body. The conduit has an open end. The open end is
configured to receive gas and air. A flow of the gas and the air
from the open end through the conduit to the body and past the
screen member is defined as a downstream direction. The screen
member defines a zone of combustion. The gas and the air is 100%
premixed together upstream of the zone of combustion. The pilot
assembly is mounted outside of the combustion chamber.
[0005] Other independent aspects of the disclosure will become
apparent by consideration of the detailed description and
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a perspective view of a water heater according to
one construction.
[0007] FIG. 2 is a perspective view of the water heater of FIG. 1
with portions removed, illustrating a flue assembly and a burner
assembly positioned within a combustion chamber of the water
heater.
[0008] FIG. 3 is bottom perspective view of a portion of the water
heater of FIG. 1, illustrating the combustion chamber of FIG.
2.
[0009] FIG. 4 is a perspective view of the burner assembly of FIG.
2.
[0010] FIG. 5 is a front perspective view of the burner assembly
coupled to a door assembly of the combustion chamber of FIG. 3.
[0011] FIG. 6 is a rear perspective view of the burner assembly and
the door assembly of FIG. 5.
[0012] FIG. 7 is a perspective view of a portion of the burner
assembly of FIG. 2.
[0013] FIG. 8 is a partial view of a portion of a burner of the
burner assembly of FIG. 7, illustrating a baffle assembly of the
burner assembly.
[0014] FIG. 9 is an end view of the baffle assembly of FIG. 8.
[0015] FIG. 10 is a partial side view of a portion of the burner
and the baffle assembly of FIG. 8.
[0016] Before any independent embodiments of the disclosure are
explained in detail, it is to be understood that the disclosure is
not limited in its application to the details of construction and
the arrangement of components set forth in the following
description or illustrated in the following drawings. The
disclosure is capable of other independent embodiments and of being
practiced or of being carried out in various ways.
DETAILED DESCRIPTION
[0017] Use of "including" and "comprising" and variations thereof
as used herein is meant to encompass the items listed thereafter
and equivalents thereof as well as additional items. Use of
"consisting of" and variations thereof as used herein is meant to
encompass only the items listed thereafter and equivalents
thereof.
[0018] Relative terminology, such as, for example, "about",
"approximately", "substantially", etc., used in connection with a
quantity or condition would be understood by those of ordinary
skill to be inclusive of the stated value and has the meaning
dictated by the context (for example, the term includes at least
the degree of error associated with the measurement of, tolerances
(e.g., manufacturing, assembly, use, etc.) associated with the
particular value, etc.). Such terminology should also be considered
as disclosing the range defined by the absolute values of the two
endpoints. For example, the expression "from about 2 to about 4"
also discloses the range "from 2 to 4." The relative terminology
may refer to plus or minus a percentage (e.g., 1%, 5%, 10% or more)
of an indicated value.
[0019] Also, the functionality described herein as being performed
by one component may be performed by multiple components in a
distributed manner. Likewise, functionality performed by multiple
components may be consolidated and performed by a single component.
Similarly, a component described as performing particular
functionality may also perform additional functionality not
described herein. For example, a device or structure that is
"configured" in a certain way is configured in at least that way
but may also be configured in ways that are not listed.
[0020] With reference to FIGS. 1 and 2, a fuel-fired atmospheric
water heater 10 is illustrated with portions removed for
illustrative purposes. The water heater 10 includes a tank 18
defining an interior space 22 (FIG. 2) for holding water, a flue
assembly 26 extending through the tank 18, and a burner assembly 30
in fluid communication with the flue assembly 26.
[0021] The tank 18 has a first, bottom end 34 (FIG. 2) and a
second, top end 38 opposite the bottom end 34 (FIG. 2). The tank 18
defines a longitudinal axis 42 extending through the bottom end 34
and the top end 38. The tank 18 supports an inlet spud 46 and an
outlet spud 50. In the illustrated embodiment, the inlet spud 46
and the outlet spud 50 are positioned at and supported by the top
end 38 of the tank 18. Further, the tank 18 is supported on a skirt
54 coupled to the bottom end 34.
[0022] A cold water supply pipe 58 communicates between a source of
cold water (not shown) and the inlet spud 46. A dip tube 62 extends
from the inlet spud 46 at the top end 38 into the tank 18 toward
the bottom end 34. Additionally, a hot water pipe 66 communicates
between a hot water access point or point-of-use (not shown) and
the outlet spud 50. The water heater 10 may further include an
anode assembly (not shown) positioned within the tank 18. The anode
assembly may be supported by and extend from the top end 38 into
the tank 18.
[0023] The hot water access point or point-of-use may be, for
example, a faucet or a water-consuming appliance. Cold water is
supplied at supply pressure (usually around 30 psi but sometimes as
high as 60 psi) from the cold water source (e.g., a water utility
or well pump) through the cold water supply pipe 58. When the
access point is opened, the hot water pipe 66 is exposed to
atmospheric pressure, which permits cold water to flow at supply
pressure into a lower portion 70 of the tank 18 via the dip tube 62
and displace hot water from an upper portion 74 of the tank 18 via
the outlet spud 50 and hot water pipe 66.
[0024] With reference to FIGS. 2 and 3, a combustion chamber 78 is
positioned axially underneath the tank 18 relative to the
longitudinal axis 42. In particular, the combustion chamber 78 is
defined by a wall member 82, an intermediate member 86, and a
bottom 90 spaced from the intermediate member 86 relative to the
longitudinal axis 42. The wall member 82 is fixedly coupled to the
tank 18. In the illustrated embodiment, although not shown, the
skirt 54 surrounds the wall member 82. In other embodiments, the
skirt 54 may itself define the combustion chamber 78.
[0025] The intermediate member 86 separates the combustion chamber
78 from the tank 18. The intermediate member 86 forms the bottom
end 34 of the tank 18. Further, the bottom 90 of combustion chamber
78 is supported on a floor or other surface of a building (e.g.,
house, etc.). The illustrated bottom 90 is formed by solid
material, and includes a 1/4 inch foil-faced layer of
insulation.
[0026] With reference to FIG. 3, the illustrated combustion chamber
78 further includes a door assembly 94 which forms a portion of the
wall member 82. The door assembly 94 includes a door 98 movably
coupled to a fixed portion of the wall member 82. Specifically, an
inner surface 102 (FIG. 6) of the door 98 defines a portion of the
combustion chamber 78. The door assembly 94 is configured to
provide access by a user to the combustion chamber 78.
[0027] Referring back to FIG. 2, the flue assembly 26 extends
through the tank 18 from the combustion chamber 78 to an exhaust
vent 106 positioned at the top end 38 of the tank 18. In
particular, the flue assembly 26 is fluidly connected to the
combustion chamber 78 through an opening in the intermediate member
86. The water heater 10 is an atmospheric water heater that does
not include any powered blowers or fans to create airflow, but
rather relies upon the natural convection of air and combustion
exhaust through the water heater 10.
[0028] With continued reference to FIG. 2, the flue assembly 26
includes a flue 110. The flue 110 is fluidly connected to the
combustion chamber 78 at a first end of the flue 110, and the
exhaust vent 106 at a second end opposite the first end. In the
illustrated embodiment, the flue assembly 26 includes one flue 110
extending through a center of the tank 18. The flue assembly 26 is
configured to receive flue gases produced by the burner assembly 30
and direct the flue gases through the one or more flues 110 to the
exhaust vent 106 for heating the water in the tank 18. With
particular reference to FIG. 2, the flue 110 includes a flue baffle
114 to improve heat transfer from the flue to the water within the
tank 18.
[0029] Condensation produced within the flue assembly 26 during
operation of the water heater 10 is directed (i.e., by gravity)
along inner walls of the flue 110 toward the combustion chamber 78.
As such, the condensation is configured to be received in the
combustion chamber 78 from the flue assembly 26. A drain line (not
shown) may be fluidly connected to the bottom 90 of the combustion
chamber 78 for withdrawing the condensation from the system.
[0030] With reference to FIGS. 2 and 4, the burner assembly 30 is
positioned within the combustion chamber 78. The burner assembly 30
and combustion chamber 78, when used together, may also be
collectively referred to as a combustion system. The burner
assembly 30 includes a burner 120, a screen member 124, and a
conduit 128 (FIG. 4). The burner assembly 30 is supported in
cantilever fashion by the door 98 of the combustion chamber 78.
[0031] With reference to FIGS. 7 and 8, the burner 120 includes a
body 132 having a plurality of surfaces 134, 138. In the
illustrated embodiment, the body 132 has an outer surface 134 and
an inner surface 138. In particular, each of the outer and inner
surfaces 134, 138, respectively, is formed by a curved surface. In
the illustrated embodiment, a cross-sectional shape of the body is
a C-shape to form the curved surfaces. As such, a shape of the body
132 may be referred to as being semi-round. The outer surface 134
is convex and the inner surface 138 is concave. The specific shape
of the burner body 132 may inhibit burner resonance, as further
discussed below.
[0032] The body 132 includes a plurality of segments 142A-142C. In
the illustrated embodiment, the body 132 includes a first segment
142A, and second and third segments 142B, 142C, respectively,
extending therefrom. Specifically, the first segment 142A includes
a first end 146 and a second end 150. The first segment 142A has a
length A (FIG. 4) measured between the first end 146 and the second
end 150. First and second side edges 154A, 154B extend between the
first and second ends 146, 150 of the first segment 142A. The
second segment 142B extends from the first end 146 parallel to the
conduit 128, and the third segment 142C extends from the second end
150 parallel to the conduit 128. Additionally, the second and third
segments 142B, 142C extend parallel to and spaced apart from each
other such that the body 132 has a U-shape. In other words, the
burner body 132 has a shape that may be termed as a horseshoe
shape. The first, second, and third segments 142A-142C define a
conduit-receiving space 158 located therebetween. The conduit 128
is in the conduit-receiving space 158 between the first and second
segments 142B, 142C. Further, each of the first, second, and third
segments 142A-142C includes the curved surfaces 134, 138.
[0033] With reference to FIG. 2, the burner assembly 30 is
positioned at a predetermined location within the combustion
chamber 78. In the illustrated embodiment, the burner assembly 30
is positioned at the predetermined location such that the first,
second, and third segments 142A-142C are not located directly
underneath the opening of the intermediate member 86. Instead, the
conduit-receiving space 158 is positioned directly underneath the
flue 110. This may reduce or eliminate the occurrence of
condensation falling from the flue assembly 26 directly onto the
burner 120. As such, the burner 120 is shaped and positioned at the
predetermined location to avoid contact with the condensation from
the flue assembly 26. In particular, flue gas condensate is known
to be acidic, with pH values in the range of 2.5-3.5. A burner life
may be increased by inhibiting or preventing contact between the
flue gas condensate and the exposed surfaces of the burner 120. As
such, the U-shape of the burner 120 may inhibit collection of
condensation on the burner 120 (i.e., screen member 124), and/or
reduce corrosion of the burner 120 or screen member 124 due to
condensation.
[0034] Each of the segments 142A-142C includes a plurality of edges
162 (FIG. 7) that form a top 164 of the body 132. The screen member
124 is movably coupled to the top 164 of the body 132. The screen
member 124 includes a first side 166 and a second, opposite side
(not shown). The first side 166 is in facing relationship with the
combustion chamber 78. The second side is in facing relationship
with the inner, curved surface 138 of the body 132. As shown in
FIG. 7, the screen member 124 is also curved or rounded such that
the first side 166 is convex (i.e., bends away from the inner
surface 138 of the body 132). The second side of the screen member
124 compliments the curve of the first side 166. The screen member
124 is formed by a mesh material. Further, the illustrated screen
member 124 comprises of a high temperature-resistant material such
as metal (e.g., stainless steel Incoloy 601 metal). The screen
member 124 defines a zone of combustion 168 of the burner assembly
30.
[0035] The screen member 124 is selectively movable relative to the
top 164 of the body 132. In particular, the top 164 of the burner
body 132 includes a flange 170 (only a top side of which is shown
in FIG. 7) extending around all of the plurality of edges 162 of
the body 132. The flange 170 is configured to bend or fold over
outer edges of the screen member 124 such that the edges of the
screen member are positioned between the flange 170. As such, the
screen member 124 is movably retained to the body 132 of the burner
120. Accordingly, the screen member 124 is configured to float
relative to the body 132. This may relieve thermal stresses that
occur within the screen member 124 as the burner 120 is
operated.
[0036] The body 132 and the screen member 124 cooperate to define
an internal chamber 174 (FIG. 8) of the burner assembly 30. The
conduit 128 extends from the body 132 and is fluidly connected to
the internal chamber 174. As noted above, the conduit 128 is
positioned in the conduit-receiving space 158 between the second
and third segments 142B, 142C, respectively. Further, the conduit
128 extends parallel to and spaced from the second and third
segments 142B, 142C, respectively. As such, the conduit 128 extends
through the conduit-receiving space 158. In the illustrated
embodiment, the conduit 128 is positioned at a center position
along the length A of the first segment 142A. In other embodiments,
the conduit 128 may be positioned at other axial positions along
the length A of the first segment 142A.
[0037] With reference to FIG. 7, the conduit 128 includes a first
end 178 and a second end 182 opposite the first end 178. The
conduit 128 further includes a passage 186 extending between the
first end 178 and the second end 182. In the illustrated
embodiment, the second side edge 154B of the first segment 142A
defines an opening 190 (FIG. 8), and the passage 186 is aligned
with the opening 190 at the second end 182 of the conduit 128.
Accordingly, the passage 186 of the conduit 128 is in fluid
communication with the internal chamber 174 of the body 132/screen
member 124. The first end 178 of the conduit 128 extends farther
than each respective end of the second and third segments 142B,
142C (i.e., it extends out of the conduit-receiving space 158).
[0038] With particular reference to FIGS. 5 and 6, the conduit 128
extends from the burner body 132 through the wall member 82 of the
combustion chamber 78. In the illustrated embodiment, the conduit
128 extends through the door 98 of the door assembly 94. In other
embodiments, the conduit 128 may extend through the wall member 82
at any other location of the combustion chamber 78. Accordingly,
the first end 178 of the conduit 128 is positioned outside of the
combustion chamber 78. Specifically, in the illustrated embodiment,
a portion of the conduit 128 is coupled by a plate member 194 and
fasteners 198 to the inner surface 102 of the door 98 (FIG. 5). The
plate member 194 is located closer to the first end 178 of the
conduit 128 than the second end 182. The burner 120 is supported in
cantilever fashion in the combustion chamber 78 by the conduit 128
which is rigidly mounted to the door 98.
[0039] With reference to FIGS. 3 and 4, an air guide member 202 is
coupled to the first end 178 of the conduit 128, outside of the
combustion chamber 78 and, in this regard is an extension of the
conduit 128. In the illustrated embodiment, the air guide member
202 is a venturi tube having a passage aligned with the passage 186
of the conduit 128. The air guide member 202 forms a venturi
portion 206 of the conduit 128. In the illustrated embodiment, the
venturi portion 206 is formed as a separate piece and coupled
(e.g., by welding, etc.) to the first end 178 of the conduit 128.
In this embodiment, the first end 178 of the conduit 128 receives a
portion of the air guide member 202. In other embodiments, the
venturi portion 206 may be formed as an integral portion of the
conduit 128 by shaping the first end 178 of the conduit 128 in the
shape of a venturi. The venturi portion 206 draws air into the
conduit 128 in response to a flow of pressurized gas flowing
through the venturi portion 206.
[0040] The water heater 10 includes a gas supply assembly 220 (FIG.
3). The gas supply assembly 220 includes a valve 224 and a gas pipe
228 fluidly connected to the valve 224. In the illustrated
embodiment, the valve 224 is supported by an outer surface of the
tank 18, and the gas pipe 228 extends from the valve 224 toward the
venturi portion 206. In some embodiments, the end of the gas pipe
228 may extend partially within the venturi portion 206. The gas
valve 224 is configured to selectively supply gas to the venturi
portion 206. In the illustrated embodiment, the gas valve 224 is
configured to provide gas flow at a constant pressure between 3.5
inches water column and 4.0 inches water column. In some
embodiments, the gas valve 224 is configured to provide gas flow at
a constant pressure of 3.5 inches water column. In other
embodiments, the gas valve 224 is configured to provide gas flow at
a constant pressure between 3.5 inches water column and 5.0 inches
water column. In particular, other water heater designs may require
a constant gas pressure at 5.0 inches water column or higher. The
illustrated water heater 10 is configured to be installed in
locations where a supply of gas cannot be maintained above a
constant pressure of 4.0 inches water column.
[0041] The gas supply assembly 220 is configured to selectively
supply gas to the venturi portion 206 such that air is drawn from
the surrounding atmosphere into the venturi portion 206 and into
the conduit 128 (e.g., by aspiration) (FIG. 4). A downstream
direction is defined as a direction of the flow of gas and air into
the conduit 128 via the venturi portion 206 to the internal chamber
174 of the body 132/screen member 124. The air mixing with the gas
upstream of the zone of combustion 168 (i.e., the screen member
124) may be termed as primary air.
[0042] With reference to FIGS. 8-10, the burner assembly 30
includes a baffle assembly 236 positioned within the internal
chamber 174. In the illustrated embodiment, the baffle assembly 236
includes a plurality of baffle members 240, 244 having a base
baffle member 240, and two curved baffle members 244 extending
therefrom (FIG. 9). The base baffle member 240 extends from the
first side edge 154A of the first segment 142A of the burner body
132 toward the second, opposite side edge 154B (FIG. 8). More
specifically, the base baffle member 240 extends toward the opening
190. The base baffle member 240 is aligned with a center of the
opening 190, and accordingly a center axis 248 of the conduit
passage 186. An edge 252 (FIG. 10) of the base baffle member 240
conforms to the curved inner surface 138 of the body 132.
[0043] The curved baffle members 244 are coupled to the base baffle
member 240. In the illustrated embodiment, each curved baffle
member 244 is coupled to a respective side of the base baffle
member 240. In one example, spot welding is used to couple the
curved baffle members 244 to the base baffle member 240. In other
embodiments, the base baffle member 240 and curved baffle members
244 may be formed by a single, integral piece. In particular, the
curved baffle members 244 each form a gull wing shape such that the
baffle assembly 236 may be termed as a gull wing baffle assembly.
The baffle assembly 236 comprises of a metal material such as 20 or
22 gauge sheet aluminized steel. The baffle assembly 236 is
configured to direct the primary air/gas mixture (mixed upstream of
the zone of combustion 168) flowing from the conduit 128 within the
internal chamber 174 of the burner assembly 30.
[0044] With reference to FIGS. 3, 5, and 6, the water heater 10
includes a pilot assembly 260. The illustrated pilot assembly 260
includes a pilot burner 264 and a spark ignitor 268. As such, the
illustrated pilot assembly 260 may be referred to as a spark pilot.
In other embodiments, the pilot assembly 260 may utilize a
resistance heating element instead of the spark ignitor 268. The
illustrated pilot assembly 260 further includes a thermocouple 272.
The pilot assembly 260 is supported by the wall member 82 of the
combustion chamber 78. In particular, the pilot assembly 260 is
supported by the door 98 of the door assembly 94. The pilot burner
264, spark ignitor 268, and thermocouple 272 extend from the inner
surface 102 of the door 98 toward the burner assembly 30 (i.e., the
screen member 124) within the combustion chamber 78 (FIG. 6). An
end of each of the pilot burner 264, spark ignitor 268, and
thermocouple 272 is positioned proximate the burner assembly 30
(i.e., the second segment 142B). In other embodiments, the pilot
assembly 260 may not include the thermocouple 272.
[0045] A pilot gas line 276 extends from the gas valve 224 to the
pilot burner 264 (FIG. 3) for selectively supplying gas to the
pilot burner 264. In the illustrated embodiment, the thermocouple
272 is positioned above the burner 120 relative to the longitudinal
axis 42, and the spark ignitor 268 is positioned next to the
thermocouple 272. Each of the pilot burner 264, spark ignitor 268,
and thermocouple 272 extends from outside of combustion chamber 78
through the door 98. As such, the pilot burner 264, spark ignitor
268, and thermocouple 272 may be accessed by a user outside of the
combustion chamber 78. In other embodiments, other components of
the pilot assembly 260 may be positioned through the door 98
outside of the combustion chamber 78. This may facilitate cleaning,
servicing, repair, and/or replacement of parts of the pilot
assembly 260.
[0046] In operation, when there is a call for heat, the gas valve
224 is selectively opened to provide gas flow at a constant
pressure. In the illustrated embodiment, the gas flow is at a
constant pressure of 3.5 inches water column. The gas flow is then
injected through an orifice of the gas valve 224 into the air guide
member 202 such that the gas flows through the air guide member 202
and subsequently the conduit 128. Air is drawn into the gas flow
stream by aspiration, and effectively mixes with the gas flow to
form a desirable homogeneous air/gas mixture before the air/gas
mixture reaches the screen member 124. In particular, the air that
is being drawn into the air guide member 202 is the primary air.
Accordingly, the primary air dilutes the gas flow prior to the gas
flow reaching the zone of combustion 168.
[0047] The baffle assembly 236 directs the primary air/gas mixture
entering the internal chamber 174 of the burner 120 from the
conduit 128 to one side or the other of the base baffle member 240.
In particular, the curved baffle members 244 separate the primary
air/gas mixture into two paths, each path directed through one of
the second and third segments 142B, 142C, respectively, of the
burner 120. Accordingly, the baffle assembly 236 may facilitate the
distribution and flow of the primary air/gas mixture through the
internal chamber 174. More specifically, the baffle assembly 236
may facilitate maintaining an even balance of pressure underneath
the screen member 124 (i.e., zone of combustion 168), thereby
reducing and/or preventing overheating in localized areas of the
screen member 124. Once the air/gas mixture flows past the screen
member 124 in the downstream direction (e.g., the air/gas mixture
enters the combustion chamber 78 via the screen member 124)
proximate the lighted pilot burner 264, the air/gas mixture is
ignited by the pilot burner 264.
[0048] The burner assembly 30 is configured such that the gas and
the air are 100% premixed together upstream of the zone of
combustion 168 (i.e., the screen member 124). In particular, all of
the air entering and flowing through the combustion system 30, 78
is introduced through the venturi portion 206. The gas is entrained
within the air resulting in a gas/air mixture ready for combustion
at the screen member 124 of the burner assembly 30. In particular,
the valve 224, the conduit 128 including the venturi portion 206,
and/or the screen member 124 is configured such that the gas and
air is 100% premixed together. This may be achieved based on one or
more of the following: a predetermined flow rate of gas controlled
by the valve 224, an airflow rate of air controlled by the venturi
portion 206, a size (e.g., length, diameter, etc.) of the conduit
128, and/or a velocity of the air/gas mixture exiting the burner
120 (i.e., past the screen member 124). For example, the screen
member 124 is configured as a backpressure device to limit the exit
velocity of the air/gas mixture through the screen member 124. More
specifically, the screen member 124 includes a plurality of holes
or perforations which define the amount of open surface area
relative to a total surface area of the screen member 124. The open
area (i.e., perforations or holes in the screen member 124)
relative to the total surface area of the screen member 124
determines the exit velocity of the air/gas mixture. As such, the
amount of open area relative to the total surface area of the
screen member 124 is selected to achieve a predetermined exit
velocity of the air/gas mixture. In the illustrated embodiment, the
open area relative to the total surface area of the screen member
124 is between 25% and 30%. In some embodiments, the open area
relative to the total surface area of the screen member 124 is
between 15% and 40%. The screen member 124 is further configured to
evenly distribute the air/gas mixture at any point located on the
zone of combustion 168. Accordingly, the air/gas mixture may be
uniformly distributed on the zone of combustion 168 such that an
even loading on the screen member 124 and/or an even balance of
pressure underneath the screen member 124 (i.e., zone of combustion
168) is achieved, thereby reducing and/or preventing overheating in
localized areas of the screen member 124. The control of the exit
velocity may also inhibit or prevent flashback.
[0049] Additionally, the exit velocity controlled by the screen
member 124 permits combustion to occur immediately downstream of
the screen member 124 relative to the downstream direction such
that the heat from the combustion flame is absorbed by the screen
member 124, thereby limiting a flame temperature of the combustion
flame to below a predetermined temperature at which nitrogen oxide
forms. As such, nitrogen oxide emissions from the combustion flame
remain below a predetermined maximum level that can be produced for
a natural gas-fired water heater.
[0050] Further, since all gas entering the combustion system 30, 78
is combusted at the zone of combustion 168 (i.e., the screen member
124), no secondary air is necessary to dilute any gas remaining
downstream of the screen member 124. In addition, the pilot
assembly 260 is fed by natural convection of air flow through the
burner assembly 30. Thus, no additional openings in the bottom 90
or combustion chamber door 98 are required to provide the pilot
assembly 260 with combustion air. Accordingly, a flammable vapor
screen does not need to be provided at the bottom 90 of the
combustion chamber 78. In other words, there are no other openings
in the bottom 90 of the combustion chamber 78 for providing
secondary air into the combustion chamber 78 that need to be
covered by a flammable vapor screen. With only one opening in the
combustion chamber 78 (i.e., the open first end 178 of the conduit
128) to ingest flammable vapors, the water heater 10 may be
configured to minimize the amount of flammable vapors entering the
combustion chamber 78.
[0051] During operation of the water heater, the burner body 132
has a first, natural vibration frequency, and flames produced by
the burner assembly at the zone of combustion 168 oscillate at a
second, predetermined vibration frequency. The first vibration
frequency occurs due to pressure pulses within the combustion
chamber 78. The second vibration frequency is based on the
oscillation of flame speed pulsations (i.e., combustion rate
fluctuations) that pass through the screen member 124. Burner
resonance may occur when the first vibration frequency synchronizes
with the second vibration frequency such that the pressure pulses
are in phase with the fluctuations in the heat released from
combustion. The curved or round shape of both the burner body 132
and the screen member 124 may increase a stiffness of the burner
120 to affect the first vibration frequency. In other words, the
first vibration frequency is determined by the round-shape of the
burner 120. A radius of the curvature of the body 132 is selected
such that the first vibration frequency is substantially greater
than the second vibration frequency. In some embodiments, the shape
of the burner 120 is configured such that the first vibration
frequency is between 1.25 and 1.75 times greater than the second
vibration frequency. In some embodiments, the shape of the burner
120 is configured such that the first vibration frequency is 1.5
times greater than the second vibration frequency. In other
embodiments, the first vibration frequency is greater than the
second vibration frequency by 150 Hz or more. In yet other
embodiments, the first vibration frequency is greater than the
second vibration frequency by 300 Hz or more. In yet still other
embodiments, the first vibration frequency is between 100 Hz and
350 HZ greater than the second vibration frequency. Accordingly,
the shape of the burner 120 is configured such that the first
vibration frequency is at a frequency where the surfaces of the
burner body 132/screen member 124 are not in resonance with the
second vibration frequency or any of its harmonics. Further, the
round shape of the burner 120 is configured to maintain the first
natural vibration frequency at a greater frequency than the second
predetermined vibration frequency throughout operation of the
burner 120. Accordingly, burner resonance is inhibited or
completely eliminated during operation.
[0052] Accordingly, various embodiments of an atmospheric gas water
heater 10 having a burner assembly 30 are described herein that is
operable to use only primary air to dilute gases for combustion to
heat the water within a tank 18. The burner assembly 30 further has
a U-shape and is positioned within the combustion chamber 78 to
avoid condensation produced in a flue assembly 26. Further, the
burner 120 of the burner assembly 30 is shaped to reduce or inhibit
burner resonance. The pilot assembly 260 is accessible by a user
outside of the combustion chamber 78 to facilitate service and
replacement of parts. Operation of the burner assembly 30 is
reliable under a minimum gas supply of 3.5 inches water column.
[0053] Although the disclosure has been described in detail with
reference to certain preferred embodiments, variations and
modifications exist within the scope and spirit of one or more
independent aspects of the disclosure as described. Various
features and/or advantages of the disclosure are set forth in the
following claims.
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