U.S. patent application number 14/142095 was filed with the patent office on 2015-07-02 for rich-lean burner.
This patent application is currently assigned to Rinnai Corporation. The applicant listed for this patent is Rinnai Corporation. Invention is credited to Kazuyuki Akagi, Hideo Okamoto.
Application Number | 20150184849 14/142095 |
Document ID | / |
Family ID | 53481256 |
Filed Date | 2015-07-02 |
United States Patent
Application |
20150184849 |
Kind Code |
A1 |
Akagi; Kazuyuki ; et
al. |
July 2, 2015 |
Rich-Lean Burner
Abstract
A rich-lean burner with a lean flame port, a blind clearance,
and a rich flame port has: a burner main body with a pair of
burner-main-body side plates on both lateral sides thereof; a
burner cap with a burner-cap side plate covering the burner main
body from at least one lateral outside thereof; and a straightening
member with straightening plates to divide the lean flame port into
laterally disposed zones. Upper ends of the burner-main-body side
plates are below upper ends of the burner-cap side plate and of the
straightening plates. The straightening member has a partition
plate which is located laterally outside an outer straightening
plate contiguous to the blind clearance and which extends upward
beyond the burner-main-body side plates. The blind clearance is
defined between the partition plate and the outer straightening
plate, and the rich flame port is defined between the partition
plate and the burner-cap side plate.
Inventors: |
Akagi; Kazuyuki; (Aichi,
JP) ; Okamoto; Hideo; (Aichi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Rinnai Corporation |
Aichi |
|
JP |
|
|
Assignee: |
Rinnai Corporation
Aichi
JP
|
Family ID: |
53481256 |
Appl. No.: |
14/142095 |
Filed: |
December 27, 2013 |
Current U.S.
Class: |
431/278 |
Current CPC
Class: |
F23D 14/46 20130101;
F23D 14/105 20130101; F23D 14/045 20130101; F23D 14/586
20130101 |
International
Class: |
F23D 14/04 20060101
F23D014/04; F23D 14/58 20060101 F23D014/58; F23D 14/08 20060101
F23D014/08; F23D 14/46 20060101 F23D014/46 |
Claims
1. A rich-lean burner comprising, on an upper end portion thereof:
a lean flame port longitudinally extended to eject a lean fuel/air
mixture which is leaner in fuel concentration than a theoretical
fuel/air ratio; a blind clearance located on at least one lateral
side of the lean flame port, the blind clearance being free from
ejection of a fuel/air mixture; and a rich flame port located
laterally outside the blind clearance thereby ejecting a rich
fuel/air mixture which is richer in fuel concentration than the
theoretical fuel/air ratio, the rich-lean burner including
constitutional elements of: a burner main body having a pair of
burner-main-body side plates lying opposite to each other on both
lateral sides of the burner main body; a burner cap having a
burner-cap side plate covering the burner main body from at least
one lateral outside thereof; and a straightening member mounted
between both the burner-main-body side plates and having a
plurality of straightening plates to divide the lean flame port
into a plurality of laterally disposed zones, characterized in:
that an upper end of each of the burner-main-body side plates is
below an upper end of the burner-cap side plate and an upper end of
each of the straightening plates; that the straightening member has
a partition plate located laterally outside an outer straightening
plate, among the plurality of straightening plates, that is
contiguous to the blind clearance, the partition plate extending
upward beyond the burner-main-body side plates, that the blind
clearance is defined between the partition plate, and the outer
straightening plate; and that the rich flame port is defined
between the partition plate and the burner-cap side plate.
2. The rich-lean burner according to claim 1, wherein the
straightening member further comprises bridge portions arranged at
a plurality of longitudinally separate positions, each of the
bridge portions connecting an upper end of the partition plate and
an upper end of the outer straightening plate.
3. The rich-lean burner according to claim 2, wherein the
straightening member further comprises constricted portions at
longitudinally separated positions that coincide with the bridge
portions, the constricted portions being arranged by laterally
bringing the plurality of straightening plates into intimate
contact with one another, thereby longitudinally dividing the lean
flame port.
4. The rich-lean burner according to claim 3, wherein the burner
cap comprises: a pair of side plates to cover the burner main body
from an outside of laterally one side and from an outside of
laterally opposite side; and bridge portions disposed at a
plurality of longitudinal positions to connect upper ends of both
the side plates, wherein each of the burner-cap bridge portions is
disposed at longitudinal positions coinciding with each of the
straightening-member bridge portions in contact with a top of each
of the straightening-member bridge portions.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The present invention relates to a rich-lean burner having
on an upper end portion thereof a lean flame port which is extended
in a back-and-forth direction (hereinafter referred to as a
"longitudinal" direction) in order to eject a lean fuel/air mixture
which is leaner in fuel concentration than a theoretical fuel/air
ratio; a blind clearance which is located on at least one
right-and-left side (hereinafter referred to as a "lateral" side)
of the lean flame port and which is free from ejection of a
fuel/air mixture; and a rich flame port which is located on a
lateral outside of the blind clearance so as to eject a rich
fuel/air mixture which is richer in fuel concentration than the
theoretical fuel/air ratio.
[0003] 2. Background Art
[0004] As this kind of rich-lean burner, there is known one having
as its constitutional elements: a burner main body including a pair
of side plates laterally lying opposite to each other; a burner cap
having a side plate covering the burner main body from outside of
at least one lateral side (the side in which the rich flame port is
disposed) of the burner main body; and a straightening member which
is mounted between both the side plates of the burner main body and
which has a plurality of straightening plates to divide the lean
flame port into a plurality of lateral zones. And the rich-lean
burner is conventionally arranged such that: an upper end of each
of the side plates of the burner main body is located on the same
height as the upper end of the side plates of the burner cap and
the upper end of each of the straightening plates; that, among a
plurality of straightening plates of the straightening member, a
blind clearance is defined between an outer straightening plate
that lies next to the blind clearance and the side plate of the
burner main body; and that a rich flame port is defined between the
side plate of the burner main body and the side plate of the burner
cap (see, e.g., JP-A-2007-285536).
[0005] Since the zones defining the lean flame port and the rich
flame port are subjected to a high temperature, the burner main
body, the burner cap, and the straightening member are made of a
stainless steel (SUS)-based material (according to Japanese
Industrial Standards, JIS) which is superior in resistivity to a
high temperature. However, that portion of the burner main body
which is subjected to a high temperature is limited to an upper end
of the side plate. Therefore, it will be a problem in cost
reduction to make the entire burner main body of an expensive
SUS-based material.
SUMMARY
Problems that the Invention is to Solve
[0006] In view of the above points, this invention has a problem of
providing a rich-lean burner in which the burner main body has
eliminated the necessity of being made of a material superior in
high-temperature durability, thereby attaining a cost
reduction.
Means for Solving the Problems
[0007] In order to solve the above problem, this invention is a
rich-lean burner comprising, on an upper end portion thereof a lean
flame port longitudinally extended to eject a lean fuel/air mixture
which is leaner in fuel concentration than a theoretical fuel/air
ratio; a blind clearance located on at least one lateral side of
the lean flame port, the blind clearance being free from ejection
of a fuel/air mixture; and a rich flame port located laterally
outside the blind clearance thereby ejecting a rich fuel/air
mixture which is richer in fuel concentration than the theoretical
fuel/air ratio. The rich-lean burner includes constitutional
elements of a burner main body having a pair of burner-main-body
side plates lying opposite to each other on both lateral sides of
the burner main body; a burner cap having a burner-cap side plate
covering the burner main body from at least one lateral outside
thereof and a straightening member mounted between both the
burner-main-body side plates and having a plurality of
straightening plates to divide the lean flame port into a plurality
of laterally disposed zones. An upper end of each of the
burner-main-body side plates is below an upper end of the
burner-cap side plate and an upper end of each of the straightening
plates. The straightening member has a partition plate located
laterally outside an outer straightening plate, among the plurality
of straightening plates, that is contiguous to the blind clearance,
the partition plate extending upward beyond the burner-main-body
side plates. The blind clearance is defined between the partition
plate and the outer straightening plate, and the rich flame port is
defined between the partition plate and the burner-cap side
plate.
[0008] According to the arrangement of this invention, the upper
end of each of the burner-main-body side plates is located below
the upper end of the burner-cap side plate and the upper end of the
straightening plates. Therefore, the burner main body is not
subjected to heating to such a high temperature. It follows that
the burner main body needs not be made of a material that is
superior in high-temperature durability.
[0009] The straightening member preferably further comprises
straightening-member bridge portions arranged at a plurality of
longitudinally separate positions, each of the bridge portions
connecting an upper end of the partition plate and an upper end of
the outer straightening plate. According to this arrangement, the
straightening-member bridge portions serve the purpose of a support
so that the lateral positional deviation of the partition plates
due to aged deterioration can be restricted. Therefore, there can
be effectively prevented the deterioration in combustibility as a
consequence of lateral changes in the widths of the rich flame port
and the blind clearance due to lateral deviation of the partition
plate.
[0010] The straightening member preferably further comprises
constricted (or gathered) portions at longitudinally separated
positions that coincide with each of the bridge portions. The
constricted portions are arranged by laterally bringing the
plurality of straightening plates into intimate contact with one
another, thereby longitudinally dividing the lean flame port.
According to this arrangement, the thermal effect by the flames to
be generated at the lean flame port onto the bridge portions can be
reduced, whereby the durability of the bridge portions is
improved.
[0011] The burner cap preferably comprises: a pair of side plates
to cover the burner main body from an outside of laterally one side
and from an outside of laterally opposite side; and burner-cap
bridge portions disposed at a plurality of longitudinal positions
to connect upper ends of both the side plates. Each of the
burner-cap bridge portions is disposed at longitudinal positions
coinciding with each of the straightening-member bridge portions in
contact with a top of each of the straightening-member bridge
portions. According to this arrangement, the burner-cap bridge
portion is cooled as a result of heat sink to the
straightening-member bridge portions which are maintained at a
relatively low temperature. As a result, the durability of the
burner-cap bridge portions can be improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a perspective view of a rich-lean burner according
to an embodiment of this invention.
[0013] FIG. 2 is a sectional view taken along the line II-II in
FIG. 1.
[0014] FIG. 3 is an exploded perspective view of a rich-lean burner
according to an embodiment of this invention.
[0015] FIG. 4 is a cut-away perspective view of an essential
portion of a rich-lean burner according to an embodiment of this
invention.
[0016] FIG. 5 is a cut-away perspective view of an essential
portion of a rich-lean burner according to a second embodiment of
this invention.
[0017] FIG. 6 is a sectional view of an essential portion of a
rich-lean burner according to a third embodiment of this
invention.
[0018] FIG. 7 is a sectional view of an essential portion of a
rich-lean burner according to a fourth embodiment of this
invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0019] With reference to FIGS. 1 and 2, reference numeral 1 denotes
a rich-lean burner according to an embodiment of this invention.
The rich-lean burner 1 has on an upper end portion thereof: a lean
flame port 2 extended in a longitudinal (i.e., back-and-forth)
direction and ejecting a lean fuel/air mixture which is leaner in
fuel concentration than a theoretical fuel/air ratio; a pair of
blind clearances 4, 4 (i.e., a clearance with lower end being
closed to passage) located on both lateral sides of the lean flame
port 2 and free from ejection of a fuel/air mixture; and a pair of
rich flame ports 3, 3 each of which is located on a lateral outside
of the blind clearance 4 on lateral one side of the lean flame port
2 and is located on a lateral outside of the blind clearance 4 on
the lateral opposite side of the lean flame port 2, the pair of
rich flame ports ejecting a rich fuel/air mixture that is richer in
fuel concentration than the theoretical fuel/air ratio.
[0020] With reference also to FIG. 3, the rich-lean burner 1 is
made up of the constitutional elements of: a burner main body 5
having a pair of side plates 51, 51 which lie laterally (i.e.,
right and left) opposite to each other; a burner cap 6 which has a
pair of side plates 61, 61 to cover the burner main body 5 from one
lateral outside, and from the other lateral outside, of the burner
main body 5; and a straightening member 7 which is mounted between
both the side plates 51, 51 of the burner main body 5 and which has
a plurality of straightening plates for dividing the lean flame
port 2 into a plurality of laterally disposed zones. Note that the
side plates 51, 51 of the burner main body 5 are also referred to
as "burner-main-body side plates" and that the side plates 61, 61
of the burner cap 6 are also referred to as "burner-cap side
plate(s)" to clarify the two kinds of "side plates."
[0021] Both the side plates 51, 51 of the burner main body 5 are
formed by bending a single piece of plate into the shape of a
principal rafter along a bending line which is the bottom edge of
the burner main body 5. The burner main body 5 is provided, by
press-forming both the side plates 51, 51: with a lean fuel/air
mixing tube portion 52 which extends forward from an inlet port 52a
which opens in a lower and rear end of the burner main body 5; and
with a lean fuel/air mixture passage portion 53 which introduces
the lean fuel/air mixture from the lean fuel/air mixing tube
portion 52 into the lean flame port 2. An area of opening of the
inlet port 52a of the lean fuel/air mixing tube portion 52 is
relatively large. A relatively large amount of primary air flows
into the lean fuel/air mixing tube portion 52 together with the
fuel gas from a lean gas nozzle (not illustrated) that lies to face
the inlet port 52a, whereby a lean fuel/air mixture is generated.
The lean fuel/air mixture passage portion 53 is extended from the
front end of the lean fuel/air mixing tube portion 52 upward so as
to expand in the longitudinal direction.
[0022] In a portion between the lean fuel/air mixing tube portion
52 and the lean fuel/air mixture passage portion 53 of the burner
main body 5, there is provided a rich fuel/air mixture passage
portion 54 which is formed by press-forming both the side plates
51, 51. The rich fuel/air mixture passage portion 54 extends
slightly forward from an inlet port 54a which opens at a rear end
of the burner main body 5, and is terminated. At a front side
surface of the rich fuel/air mixture passage portion 54, there are
provided outlet openings 54b. An area of opening of the inlet port
54a of the rich fuel/air mixing tube portion 54 is relatively
small. A relatively small amount of primary air flows into the rich
fuel/air mixing tube portion 54 together with the fuel gas from a
rich gas nozzle (not illustrated) that faces opposite to the inlet
port 54a, whereby a rich fuel/air mixture is generated.
[0023] The rich fuel/air mixture ejected from the outlet openings
54b of the rich fuel/air mixture passage portion 54 is introduced
into each of the rich flame ports 3 through a rich fuel/air mixture
passage portion 62 to be defined between each of the side plates 51
of the burner main body 5 and each of the side plates 61 of the
burner cap 6. At a plurality of positions distributed in the
longitudinal direction in an upper portion of each of the side
plates 61 of the burner cap 6, there are formed recessed portions
63 which divide the rich flame ports 3 in a longitudinal
direction.
[0024] The straightening member 7 has a pair of inner straightening
plates 71in located on a laterally inside, and a pair of outer
straightening plates 71out located on laterally both sides. The
straightening member 7 further has constricted (or gathered)
portions 72 which bring the inner straightening plates 71in and the
outer straightening plates 71out laterally into intimate contact
with one another, thereby dividing the lean flame port 2 into a
plurality of longitudinally divided constricted portions 72. In
addition, the respective inner straightening plate 71in and the
adjacent outer straightening plate 71out are connected together by
means of folded joint portions 73 which are disposed at a plurality
of longitudinal positions at a bottom end of the straightening
plates 71in, 71out.
[0025] By the way, in this embodiment, an arrangement is made as
shown in FIGS. 2 and 4, i.e., that each of the side plates 51 of
the burner main body 5 is formed such that the upper end of each of
the side plates 51 is located below the upper end of each of the
side plates 61 of the burner cap 6 and the upper end of each of the
straightening plates 71in, 71out. On the other hand, the
straightening member 7 is provided with a pair of partition plates
74, 74 which are located laterally outside both the outer
straightening plates 71out, 71out and which extend upward beyond
each of the side plates 51, 51 in a state of being in close
contact, without a gap, with an inner surface on an upper end of
each of the side plates 51, 51 of the burner main body 5. It is
thus so arranged that each of the rich flame ports 3 is defined
between each of the partition plates 74 and each of the side plates
61 of the burner cap 6.
[0026] In addition, near the upper end of each of the side plates
51 of the burner main body 5, there are formed dented portions 55
which are dented laterally inward to approach each of the outer
straightening plates 71 of the straightening member 7. Into the gap
between the dented portions 55 and the respective outer
straightening plates 71out, there is inserted a lower end portion
of each of the partition plates 74 so as to clog or close the gap.
It is thus so arranged that each of the blind clearances 4 is
defined between each of the partition plates 74 and each of the
outer straightening plates 71out.
[0027] In the above-mentioned arrangement, the burner cap 6 and the
straightening member 7 are subjected to heating by the flames (rich
flames) to be generated in the rich flame ports 3 and by the flames
(lean flames) to be generated in the lean flame ports 2,
respectively. They must therefore be made of a material such as
stainless steel SUS430, etc. according to JIS, which is superior in
resistivity to high temperature. On the other hand, since each of
the side plates 51 of the burner main body 5 is arranged such that
the upper ends of the side plates 51 are below the partition plates
74 whose upper ends define the rich flame ports 3, the side plates
51 do not rise to a considerably high temperature. Therefore, the
burner main body 5 that constitutes the majority of the rich-lean
burner 1 needs not be made of a material that is superior in
resistivity to high temperature. Instead, the burner main body 5
may be made of a relatively inexpensive material of "SA1D" grade or
the like which corresponds to aluminized steel according to JIS
G3314--SA1D (drawing quality), thereby contributing to the cost
reduction.
[0028] In addition, according to this embodiment, there are
provided bridge portions 75 which connect an upper end of each of
the partition plates 74 and an upper end of each of the outer
straightening plates 71out at a plurality of longitudinal positions
of the straightening member 7. According to this arrangement, the
bridge portions 75 serve the purpose of supports so that the
lateral deviation of the partition plates 74 due to aged
deterioration thereof can be prevented. Therefore, the
combustibility can be effectively prevented from deteriorating as a
result of changes in lateral widths of the rich flame ports 3 or
the blind clearances 4 due to lateral deviation of the partition
plates 74.
[0029] Still furthermore, according to this embodiment, at such
longitudinally separated positions of the straightening member 7 as
will coincide with each of the bridge portions 75, there are
provided the constricted portions 72 that longitudinally divide the
lean flame port 2. According to this arrangement, the bridge
portions 75 are located at the positions at which the lean flame
port 2 is divided. As a result, the thermal effect on the bridge
portions 75 by the lean flames can be reduced, thereby improving
the durability of the bridge portions 75.
[0030] In addition, the burner cap 6 has bridge portions 64, at a
plurality of longitudinal positions, which connect together the
upper ends of both the side plates 61, 61. Each of the bridge
portions 64 of the burner cap 6 (also referred to as "burner-cap
bridge portions") is disposed at longitudinal positions that
coincide with the respective bridge portions 75 of the
straightening member 7 (also referred to as "straightening-member
bridge portions) such that the burner-cap bridge portion 64 comes
into contact with the upper surface of the straightening-member
bridge portion 75. According to this arrangement, that bridge
portion 64 of the burner cap 6 which is heated by the rich flames
to a high temperature is cooled by the heat sink to the
straightening-member bridge portion 75 which is maintained at a
relatively low temperature. As a result, the durability of the
bridge portions 64 of the burner cap 6 is also improved.
[0031] In a second embodiment as shown in FIG. 5, the bridge
portion 75 which connects the upper end of each of the partition
plates 74 and the upper end of each of the outer straightening
plates 7 lout is not provided. Instead, there may be employed an
arrangement in which each of the outer straightening plates 71out
and each of the partition plates 74 are connected together at
folded connecting portions 76 which are provided at a plurality of
longitudinal lower end positions.
[0032] Furthermore, in a third embodiment as shown in FIG. 6, the
following arrangement is employed in which the side plate 61 on
laterally one side (right side as seen in FIG. 6) of the burner cap
6 is overlapped with the partition plate 74 on the right side of
the straightening member 7, whereby the right-side rich flame port
3 may be eliminated. In this case, a similar rich-lean burner 1 is
provided on the right side thereof in parallel with each other. And
the rich flame port 3 on the left side of the latter (right-side)
rich-lean burner 1 is arranged to be in close contact with the
blind clearance 4 on the right side of the former (left-side as
seen in FIG. 6) rich-lean burner 1.
[0033] Still furthermore, according to a fourth embodiment as shown
in FIG. 7, it is possible to eliminate not only the rich flame port
3 on the laterally one side (right side as seen in FIG. 7), but
also the right-side blind clearance 4, the side plate 61 on the
right side of the burner cap 6, and the partition plate 74 on the
right side of the straightening member 7. In this case, a similar
rich-lean burner 1 is disposed on the right side of the rich-lean
burner 1 in parallel with each other. Between the outer
straightening plate 71out on the right side of the straightening
member 7 of the former rich-lean burner 1, and the side plate 61 on
the left side of the burner cap 6 of the latter rich-lean burner 1,
there is defined a blind clearance 4' which is located between the
lean flame port 2 of the former rich-lean burner 1 and the rich
flame port 3 of the latter rich-lean burner 1.
* * * * *