U.S. patent application number 12/373008 was filed with the patent office on 2009-11-26 for burner.
This patent application is currently assigned to MITSUBISHI HEAVY INDUSTRIES, LTD.. Invention is credited to Akira Goto, Naohiko Matsuda, Keiichi Nakagawa, Shigeru Nojima, Katsuki Yagi.
Application Number | 20090291401 12/373008 |
Document ID | / |
Family ID | 39032961 |
Filed Date | 2009-11-26 |
United States Patent
Application |
20090291401 |
Kind Code |
A1 |
Nakagawa; Keiichi ; et
al. |
November 26, 2009 |
BURNER
Abstract
An object of the present invention is to provide a burner such
as a two-fluid spray burner which can produce a large amount of
combustion exhaust gas with a simple structure, does not cause
unburned gas and accidental fire, and furthermore can provide
shortened flame and a uniform distribution of the flow rate of the
combustion exhaust gas. Accordingly, the burner includes: a
cylindrical combustion air passage (15) formed between a two-fluid
sprayer (12) and a burner outer cylinder (48) surrounding a
periphery of the two-fluid sprayer; a plate (shield plate) (18)
separating the combustion air passage and a combustion space
portion (13); and a combustion air passage hole (52) provided in
the outer periphery of the plate. Combustion air (50) flowing down
the combustion air passage is blocked by the plate and introduced
to the outer periphery of the plate to be kept away from the
two-fluid spray nozzle (38). The combustion air then flows through
the combustion air passage hole into the combustion space portion.
Furthermore, a first cylinder (16) for delaying supply of the
combustion air and a second cylinder (17) for preventing stagnation
are provided on the undersurface of the plate. A throttle plate
with a passage hole opened in central part is provided in the
combustion space portion.
Inventors: |
Nakagawa; Keiichi;
(Hiroshima, JP) ; Matsuda; Naohiko; (Hiroshima,
JP) ; Yagi; Katsuki; (Hiroshima, JP) ; Nojima;
Shigeru; (Hiroshima, JP) ; Goto; Akira;
(Yokohama, JP) |
Correspondence
Address: |
WESTERMAN, HATTORI, DANIELS & ADRIAN, LLP
1250 CONNECTICUT AVENUE, NW, SUITE 700
WASHINGTON
DC
20036
US
|
Assignee: |
MITSUBISHI HEAVY INDUSTRIES,
LTD.
Tokyo
JP
NIPPON OIL CORPORATION
Tokyo
JP
|
Family ID: |
39032961 |
Appl. No.: |
12/373008 |
Filed: |
August 7, 2007 |
PCT Filed: |
August 7, 2007 |
PCT NO: |
PCT/JP2007/065402 |
371 Date: |
March 26, 2009 |
Current U.S.
Class: |
431/181 |
Current CPC
Class: |
F23D 11/107 20130101;
F23D 11/404 20130101 |
Class at
Publication: |
431/181 |
International
Class: |
F23D 11/10 20060101
F23D011/10 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 11, 2006 |
JP |
2006-219575 |
Apr 27, 2007 |
JP |
2007-118087 |
Claims
1. A burner which sprays fuel from a fuel spray nozzle of a fuel
spray to a combustion space portion under the fuel spray nozzle for
combustion and burns the fuel, the burner characterized by
comprising: a cylindrical combustion air passage formed between the
fuel spray and a burner outer cylinder surrounding a periphery of
the fuel spray; a shield plate separating the combustion air
passage and the combustion space portion; and a combustion air
passage hole provided at the outer periphery of the shield plate,
characterized in that the combustion air flowing down the
combustion air passage is blocked by the shield plate and
introduced to the outer periphery of the shield plate to be kept
away from the fuel spray nozzle and then flown through the
combustion air passage hole into the combustion space portion.
2. The burner according to claim 1, characterized in that a
cylinder extending downward from a undersurface of the shield plate
for delaying supply of combustion air is provided to form different
cylindrical combustion air passage between the extending cylinder
and the burner outer cylinder, the different cylindrical combustion
air passage leading to the combustion air passage hole, and the
combustion air passing through the combustion air passage hole
flows down the different combustion air passage into the combustion
space portion from a lower end of the different combustion air
passage.
3. The burner according to claim 2, characterized in that one or a
plurality of cylinders for preventing stagnation extending downward
from the undersurface of the shield plate are provided within the
cylinder for delaying supply of combustion air.
4. The burner according to claim 1, characterized in that the
shield plate includes a plurality of other combustion air passage
holes in a position inner to the center than the combustion air
passage hole.
5. The burner according to claim 1, characterized in that the fuel
spray sprays liquid fuel from the fuel spray nozzle, a cylindrical
gas fuel passage is formed between a gas fuel supply tube
surrounding a periphery of the fuel spray and the fuel spray, and
gas fuel flows down the gas fuel passage and is sprayed to the
combustion space portion from a lower end of the gas fuel passage
and is burned.
6. The burner according to claim 1, characterized in that a
throttle plate with a passage hole opened in a central part is
provided for the combustion space portion, and combustion air
flowing down the combustion space portion is introduced by the
throttle plate to the central part of the combustion space portion
and then passed through the passage hole of the throttle plate.
7. The burner according to claim 6, characterized in that swirling
blades are provided above the throttle plate, and the combustion
air passing through the passage hole of the throttle plate is
formed into a swirling flow by the swirling blades.
8. The burner according to claim 6, characterized in that a porous
plate with a passage hole in a central part is provided above the
throttle plate in the combustion space portion, and a part of the
combustion air flowing down the combustion space portion is
introduced by the porous plate to the central part of the
combustion space portion to pass through the passage hole of the
porous plate.
9. The burner according to claim 7, characterized in that a porous
plate with a passage hole in a central part is provided above the
throttle plate in the combustion space portion, and a part of the
combustion air flowing down the combustion space portion is
introduced by the porous plate to the central part of the
combustion space portion to pass through the passage hole of the
porous plate.
Description
TECHNICAL FIELD
[0001] The present invention relates to a burner and is usefully
applied to, for example, a two-fluid spray burner which burns
liquid fuel atomized with atomizing gas.
BACKGROUND ART
[0002] A two-fluid spray burner burns liquid fuel atomized with
atomizing gas and is used as a heat source of a reformer of a fuel
cell power generation system, for example. In this case, the
reformer steam-reforms a fuel for reformation such as methane gas
or kerosene using heat of combustion exhaust gas generated by
combustion at the two-fluid spray burner to produce reformed gas
(hydrogen-rich gas) and then supplies the reformed gas to a fuel
cell as a fuel for power generation.
[0003] A conventional two-fluid spray burner employs a system of
supplying air in separate two steps in the case of generating a
large amount of combustion exhaust gas for the purposes of heating
a large-size reformer or the like. In such a case, at the first
step, liquid fuel, such as kerosene, sprayed from a nozzle of the
two-fluid spray burner is mixed with air supplied from an air
supply source and burned. At the second step, air is supplied to
the combustion exhaust gas generated by the combustion in the first
step from another air supply source. The air is supplied at a place
different from a place where the air is supplied in the first step,
thus producing a large amount of combustion exhaust gas.
[0004] Patent Document 1: Japanese Patent Laid-open No.
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0005] However, in the aforementioned conventional two-fluid spray
burner, in addition to the air supplied for the combustion in the
first step, air is supplied again at the different place in the
second step. Accordingly, the air supply structure becomes
complicated and the apparatus size increases as a whole. If a large
amount of combustion exhaust gas is intended to be produced by
supplying a large amount of air in a single step, without
separately supplying air twice at the first and second steps, the
large amount of supplied air excessively cools flame, thus leading
to reduction in evaporation rate of the liquid fuel or reduction in
reaction speed of fuel and oxygen. This lengthens the flame and
often produces unburned gas and unburned liquid fuel (mist), thus
causing accidental fire.
[0006] In the light of the aforementioned circumstances, an object
of the present invention is to provide a burner, such as a
two-fluid spray burner, which is capable of producing a large
amount of combustion exhaust gas with a simple structure, does not
produce unburned gas and cause accidental fire, and furthermore can
provide shortened flame and a uniform distribution of the flow rate
of the combustion exhaust gas.
Means for Solving the Problems
[0007] A burner of a first invention to solve the aforementioned
problems is a burner which sprays fuel (gas fuel, liquid fuel or
two fluid of liquid fuel and atomizing gas) from a fuel spray
nozzle of a fuel spray to a combustion space portion under the fuel
spray nozzle for combustion, and which burns the fuel, the burner
characterized by comprising:
[0008] a cylindrical combustion air passage formed between the fuel
spray and a burner outer cylinder surrounding a periphery of the
fuel spray;
[0009] a shield plate separating the combustion air passage and the
combustion space portion; and
[0010] a combustion air passage hole provided at the outer
periphery of the shield plate, characterized in that
[0011] the combustion air flowing down the combustion air passage
is blocked by the shield plate and introduced to the outer
periphery of the shield plate to be kept away from the fuel spray
nozzle and then flown through the combustion air passage hole into
the combustion space portion.
[0012] A burner of a second invention is the burner of the first
invention, characterized in that
[0013] a cylinder extending downward from an undersurface of the
shield plate for delaying supply of combustion air is provided to
form a different cylindrical combustion air passage between the
extending cylinder and the burner outer cylinder, the different
cylindrical combustion air passage leading to the combustion air
passage hole, and
[0014] the combustion air passing through the combustion air
passage hole flows down the different combustion air passage an
thereafter flows into the combustion space portion from a lower end
of the different combustion air passage.
[0015] A burner of a third invention is the burner of the second
invention, characterized in that
[0016] one or a plurality of cylinders for preventing stagnation
extending downward from the undersurface of the shield plate are
provided within the cylinder for delaying supply of combustion
air.
[0017] A burner of a fourth invention is the burner of any one of
the first to third inventions, characterized in that the shield
plate has a plurality of other combustion air passage holes formed
in a positions closer to the center than the combustion air passage
hole.
[0018] A burner of a fifth invention is the burner of any one of
the first to fourth inventions, characterized in that
[0019] the fuel spray sprays liquid fuel from the fuel spray
nozzle,
[0020] a cylindrical gas fuel passage is formed between a gas fuel
supply tube surrounding a periphery of the fuel spray and the fuel
spray, and
[0021] gas fuel flows down the gas fuel passage and is sprayed to
the combustion space portion from a lower end of the gas fuel
passage and is burned.
[0022] A burner of a sixth invention is the burner of any one of
the first to fifth inventions, characterized in that
[0023] a throttle plate with a passage hole opened in a central
part thereof is provided in the combustion space portion, and
[0024] combustion air flowing down the combustion space portion is
guided by the throttle plate to a central part of the combustion
space portion and then passed through the passage hole of the
throttle plate.
[0025] A burner of a seventh invention is the burner of the sixth
invention, characterized in that
[0026] swirling blades are provided above the throttle plate,
and
[0027] the flow of the combustion air passing through the passage
hole of the throttle plate is formed into a swirling flow by the
swirling blades.
[0028] A burner of an eighth invention is the burner of the sixth
or seventh invention, characterized in that
[0029] a porous plate with a passage hole in a central part thereof
is provided above the throttle plate in the combustion space
portion, and
[0030] a part of the combustion air flowing down the combustion
space portion is guided by the porous plate to the central part of
the combustion space portion to pass through the passage hole of
the porous plate.
[0031] When the burner of any one of the aforementioned first to
eighth inventions is a two-fluid spray burner, the two-fluid spray
burner may have anyone of configurations described below.
[0032] Specifically, according to a first configuration, the burner
of any one of the first to eighth inventions is a two-fluid spray
burner which atomizes liquid fuel with atomizing gas and burns the
atomized liquid fuel, the two-fluid spray burner characterized by
comprising:
[0033] a liquid fuel tank having: a cylindrical side portion and a
bottom portion provided at a lower end of the side portion, the
liquid fuel tank storing liquid fuel supplied from a liquid fuel
supply tube and discharging the stored liquid fuel from one or a
plurality of liquid fuel discharge hole opened at a position below
a liquid level of the stored liquid fuel in the side or bottom
portion, characterized in that
[0034] the liquid fuel discharged from the liquid fuel discharge
holes of the liquid fuel tank is atomized with the atomizing gas
and burned.
[0035] A two-fluid spray burner of the second configuration is the
two-fluid spray burner of the first two-fluid spray burner,
characterized in that
[0036] the liquid fuel discharge holes are opened in the bottom
portion of the liquid fuel tank, and the burner further
includes:
[0037] a cylindrical atomizing gas passage formed between the side
portion of the liquid fuel tank and an outer cylinder surrounding a
periphery of the side portion; and
[0038] a two-fluid spray nozzle provided at a lower end portion of
the outer cylinder and including a lower nozzle main body and an
upper atomizing gas introduction portion, the two-fluid spray
nozzle having:
[0039] a two-fluid converging space portion formed under the liquid
fuel discharge holes, in central part of the nozzle main body and
the atomizing gas introduction portion;
[0040] one or a plurality of spray holes formed in the nozzle main
body and leading to the two-fluid converging space portion; and
[0041] one or a plurality of grooves formed in the atomizing gas
introduction portion and allowing the two-fluid converging space
portion and the atomizing gas passage to communicate with each
other, the burner characterized in that
[0042] the liquid fuel tank is installed on the atomizing gas
introduction portion, and
[0043] the liquid fuel which is discharged from the liquid fuel
discharge holes to flow into the two-fluid converging space portion
converges at the two-fluid converging space portion with the
atomizing gas which flows down the atomizing gas passage and flows
through the grooves at the atomizing gas introduction portion to be
introduced to the two-fluid converging space portion, and the
liquid fuel is then sprayed together with the atomizing gas from
the one or plurality of spray holes.
[0044] A two-fluid spray burner of a third configuration is the
two-fluid spray burner of the second configuration, in which
[0045] an undersurface of the bottom portion of the liquid fuel
tank is formed as a tapered surface portion, which is tapered
[0046] an top surface of the atomizing gas introduction portion is
also formed a tapered surface portion, which is tapered
[0047] the liquid fuel tank is installed on the atomizing gas
introduction portion with the tapered surface portion of the liquid
fuel tank being abutted and fitted to the tapered surface portion
of the atomizing gas introduction portion.
[0048] A two-fluid spray burner of a fourth configuration is the
two-fluid spray burner of the first configuration, characterized in
that
[0049] the one or plurality of liquid fuel discharge holes are
opened in the bottom portion of the liquid fuel tank,
[0050] the burner characterized by further comprising: [0051] a
cylindrical atomizing gas passage formed between the side portion
of the liquid fuel tank and an outer cylinder surrounding a
periphery of the side portion; and [0052] a two-fluid spray nozzle
provided at a lower end portion of the outer cylinder, the
two-fluid spray nozzle having: [0053] a two-fluid converging space
portion located in central part under the liquid fuel discharge
holes and [0054] one or a plurality of spray holes leading to the
two-fluid converging space portion, the burner characterized in
that
[0055] the undersurface of the bottom portion of the liquid fuel
tank is formed as a tapered surface portion which is tapered,
[0056] the top surface of the two-fluid spray nozzle is formed as a
tapered surface portion which is tapered,
[0057] the liquid fuel tank is installed on the two-fluid spray
nozzle with the tapered surface portion of the liquid fuel tank
being abutted and fitted to the tapered surface portion of the
two-fluid spray nozzle,
[0058] one or a plurality of grooves are formed at the bottom
portion of the liquid fuel tank, the grooves allowing the atomizing
gas passage and the two-fluid converging space portion to
communicate with each other, and
[0059] the liquid fuel which is discharged from the liquid fuel
discharge holes to flow into the two-fluid converging space portion
converges at the two-fluid converging space portion with the
atomizing gas which flows down the atomizing gas passage and then
flows through the one or plurality of grooves at the bottom portion
of the liquid fuel tank to be introduced to the two-fluid
converging space portion, and the liquid fuel is then sprayed
together with the atomizing gas from the one or plurality of spray
holes.
[0060] A two-fluid spray burner of a fifth configuration is the
two-fluid spray burner of any one of the second to fourth
configuration, in which
[0061] the two-fluid converging space portion has a circular shape
in a top view, and
[0062] the grooves of the atomizing gas introduction portion or the
grooves of the bottom portion of the liquid fuel tank are formed
along tangent directions of a circumference of the two-fluid
converging space portion in the top view.
[0063] A two-fluid spray burner of a sixth configuration is the
two-fluid spray burner of any one of the second to fourth
configuration, characterized in that
[0064] the two-fluid converging space portion has a circular shape
in a top view, and
[0065] the grooves of the atomizing gas introduction portion or the
grooves of the bottom portion of the liquid fuel tank are formed
along radial directions of the two-fluid converging space portion
in the top view.
[0066] A two-fluid spray burner of a seventh configuration is the
two-fluid spray burner of the fifth or sixth configuration,
characterized in that the plurality of grooves of the atomizing gas
introduction portion or the plurality of grooves of the bottom
portion of the liquid fuel tank are formed at positions
rotationally symmetric around a central axis of the two-fluid
converging space portion.
[0067] A two-fluid spray burner of an eighth configuration is the
two-fluid spray burner of any one of the second to seventh
invention, further comprising:
[0068] a press member pressing the liquid fuel tank downward,
characterized in that
[0069] the bottom portion of the liquid fuel tank is pressed
against the atomizing air introduction portion of the two-fluid
spray nozzle to be brought into firm contact with the same or
[0070] the bottom portion of the liquid fuel tank is pressed
against the two-fluid spray nozzle to be brought into firm contact
with the same.
[0071] A two-fluid spray burner of a ninth configuration is the
two-fluid spray burner of the two-fluid spray burner of the first
configuration, in which
[0072] the liquid fuel discharge holes are opened in the bottom
portion of the liquid fuel tank, the burner further including:
[0073] a cylindrical first atomizing gas passage formed between the
side portion of the liquid fuel tank and an outer cylinder
surrounding a periphery of the side portion; and
[0074] a two-fluid spray nozzle provided at a lower end portion of
the outer cylinder, the two-fluid spray nozzle having; [0075] a
two-fluid converging space portion formed in central part under the
one or plurality of liquid fuel discharge holes: and [0076] one or
a plurality of spray holes formed, leading to the two-fluid
converging space portion, the burner characterized in that
[0077] the top surface of the two-fluid spray nozzle is formed as a
tapered surface portion which is tapered,
[0078] the undersurface of the bottom portion of the liquid fuel
tank is formed as a tapered surface portion which is tapered,
[0079] a plurality of supporting portions are provided in a
protruding manner in the side portion of the liquid fuel tank, and
each undersurface of the supporting portion is formed as tapered
surface portion,
[0080] the liquid fuel tank is installed on the two-fluid spray
nozzle with the tapered surface portion of the two-fluid spray
nozzle being abutted and fitted to the tapered surface portions of
the supporting portions,
[0081] gap formed by the supporting portions between the tapered
surface portion of the liquid fuel tank and the tapered surface
portion of the two-fluid spray nozzle is a second atomizing gas
passage, and
[0082] liquid fuel discharged from the liquid fuel discharge holes
to flow into the two-fluid converging space portion converges at
the two-fluid converging space portion with the atomizing gas which
flows down the first atomizing gas passage, passes through
atomizing gas passage portions between the supporting portions, and
then flows through the second atomizing gas passage to be
introduced to the two-fluid converging space portion, and the
liquid fuel is then sprayed together with the atomizing gas from
the spray holes.
[0083] A two-fluid spray burner of a tenth configuration is the
two-fluid spray burner of any one of the second to ninth
configuration, characterized in that
[0084] the two-fluid converging space portion is a reverse conical
shape, and the spray holes are formed at a vertex position of the
reverse conical space.
[0085] A two-fluid spray burner of an eleventh configuration is the
two-fluid spray burner of any one of the first to tenth
configuration, characterized in that
[0086] an end of the liquid fuel supply tube is in contact with an
inner peripheral surface of the side portion of the liquid fuel
tank.
EFFECTS OF THE INVENTION
[0087] According to the burner of the first invention, the
combustion air flowing down the combustion air passage is blocked
by the shield plate and introduced to the outer periphery of the
shield plate to be kept away from the fuel spray nozzle. The
combustion air then passes through the combustion air passage hole
and flows into the combustion space portion. Accordingly, in the
combustion space portion, only a part of the combustion air is
mixed with fuel sprayed from the fuel spray nozzle and used for
combustion of the fuel, and the residual of the combustion air
further flows downward and is mixed with the combustion exhaust gas
generated by the combustion. This can achieve proper mixture of the
combustion air and fuel by one supply of the combustion air (one
step) and produce a large amount of combustion exhaust gas without
excessively cooling the flame. It is therefore possible to make a
burner such as a two-fluid spray burner which is capable of
producing a large amount of combustion exhaust gas with a simple
structure and does not generate unburned gas and cause accidental
fire.
[0088] Moreover, the combustion air is caused by the shield plate
to flow into the combustion space portion at the position away from
the fuel spray nozzle. Accordingly, the position where a part of
the combustion air is supplied to fuel can be set downward away
from the shield plate. The position of flame is also set downward
away from the shield plate, thus preventing adherence of soot to
the undersurface of the shield plate. A lot of soot adhering to the
lower surface of the shield plate may cause disadvantages such as
clogging of the fuel spray nozzle and abnormal heating of the fuel
spray due to absorption of radiation heat from flame. However, by
preventing adherence of soot to the undersurface of the shield
plate as described above, such disadvantages can be prevented from
occurring.
[0089] According to the two-fluid spray burner of the second
invention, the cylinder extending downward from the undersurface of
the shield plate for delaying supply of the combustion air is
provided, and different cylindrical combustion air passage leading
to the combustion air passage hole is formed between the extending
cylinder and the burner outer cylinder. The combustion air which
flows through the combustion air passage hole is thus allowed to
flow down the different combustion air passage and then flow into
the combustion space portion from the lower end of the different
combustion air passage. It is therefore possible to delay supply of
a part of the combustion air to the fuel sprayed from the fuel
spray nozzle. In other words, the position where a part of the
combustion air is supplied to the fuel can be set downward away
from the shield plate. Accordingly, the position of flame is set
downward away from the shield plate, thus preventing adherence of
soot to the undersurface of the shield plate. The operational
effect of setting the position where a part of the combustion air
is supplied to the fuel downward away from the shield plate can be
also obtained by provision of only the shield plate as described
above. However, as described in the second invention, by providing
the cylinder for delaying supply of the combustion air, the
position where a part of the combustion air is supplied to the fuel
can be more surely set downward away from the shield plate.
[0090] In the aforementioned first invention, when the shield plate
cannot be made so large because of restriction on size of the
burner and the like and the distance between the fuel spray nozzle
and combustion air hole cannot be made long enough, the amount of
the combustion air supplied to the fuel is too much, and the flame
could be excessively cooled. On the contrary, by providing the
cylinder for delaying supply of combustion air like the second
invention, the position where a part of the combustion air is
supplied to the liquid fuel can be set downward away from the
shield plate, and the part of the combustion air supplied to the
fuel can be reduced to a proper amount. Accordingly, provision of
the cylinder like the second invention is effective based on such a
perspective. By providing the cylinder, the shield plate can be
reduced in size, and the burner can be miniaturized.
[0091] According to the two-fluid spray burner of the third
invention, the one of plurality of cylinders for preventing
stagnation extending from the undersurface of the shield plate are
provided within the cylinder for delaying supply of combustion air.
Accordingly, stagnation (convection) of the fuel can be prevented
by the cylinder for preventing stagnation from occurring near the
undersurface of the shield plate. It is therefore possible to
prevent the fuel stagnating near the undersurface of the shield
plate from catching fire and soot adhering to the undersurface of
the shield plate.
[0092] According to the two-fluid spray burner of the fourth
invention, the one or plurality of different combustion air holes
are formed in the shield plate in a position inner to the center
than the one or plurality of combustion air holes, so that a part
of the combustion air flows through these other combustion air
holes. Accordingly, such a flow of the combustion air can suppress
stagnation of the combustion air occurring near the undersurface of
the shield plate, thus preventing adherence of soot to the
undersurface of the shield plate. Moreover, the cool combustion air
flows near the fuel spray nozzle through the different combustion
air holes. It is therefore possible to obtain an effect of cooling,
with the combustion air, the fuel spray nozzle which tends to be
excessively heated by radiation heat from flame.
[0093] According to the two-fluid spray burner of the fifth
invention, the two-fluid spray burner includes the fuel spray
spraying liquid fuel from the fuel spray nozzle and a cylindrical
gas fuel passage formed between a gas fuel supply tube surrounding
a periphery of the fuel spray and the fuel spray. The gas fuel
flows down the gas fuel passage and is then sprayed from the lower
end of the gas fuel passage into the combustion space portion to be
burned. Accordingly, the gas fuel sprayed from the cylindrical gas
fuel passage is uniform in the circumferential direction. It is
therefore possible to improve the combustion characteristics, thus
exerting a flame holding effect by the gas fuel when the liquid
fuel is supplied at a low flow rate, for example.
[0094] According to the burner of the sixth invention, the throttle
plate with the passage hole opened in the central part is provided
in the combustion space portion to allow the combustion air flowing
down the combustion space portion to be introduced to the central
part of the combustion space portion by the throttle plate and pass
through the passage hole of the throttle plate, thus promoting the
mixture of the combustion air and unburned gas. Accordingly, the
promotion of combustion of the unburned gas allows the fuel to be
completely burned and can shorten the flame. Moreover, the fluid
such as the combustion air is once throttled by the passage hole of
the throttle plate, so that the distribution of the flow rate of
the fluid can be equalized in the circumferential direction. It is
therefore possible to heat a furnace or the like with the
combustion exhaust gas uniformly in the circumferential
direction.
[0095] According to the burner of the seventh invention, the
swirling blades are provided above the throttle plate to form the
flow of the combustion air passing through the passage hole of the
throttle plate into a swirling flow. Accordingly, the combustion
air passing through the passage hole of the throttle plate swirls
and spreads in the horizontal direction. Pressure of the central
part of the flowing combustion air is therefore reduced in a
position under the passage hole, thus generating a circulating flow
of the combustion air from the outside into the central part.
Accordingly, the mixture of the combustion air and unburned gas is
further promoted, so that the combustion of the unburned gas is
further promoted. Fuel is therefore more likely to be completely
burned, and the flame is further shortened.
[0096] According to the burner of the eighth invention, the porous
plates each having the passage hole opened in the central part are
provided above the throttle plate in the combustion space portion
so that a part of the combustion air flowing down the combustion
space portion is introduced to the central part of the combustion
space portion by the porous plates and passes through the passage
holes of the porous plates. Accordingly, the mixture of the
combustion air and unburned gas is further promoted, and the
combustion of the unburned gas is further promoted. The fuel is
therefore more likely to be completely burned, and the flame is
further shortened.
[0097] According to the two-fluid spray burner of the first
configuration, the two-fluid spray burner is provided with the
liquid fuel tank having: the cylindrical side portion and the
bottom portion provided at the lower end of the side portion, the
liquid fuel tank storing the liquid fuel supplied from the liquid
fuel supply tube and discharges the stored liquid fuel through the
one or plurality of liquid fuel discharge holes which are opened at
a position below the liquid level of the stored liquid fuel in the
side or bottom portion. The liquid fuel discharged from the liquid
fuel discharge holes of the liquid fuel tank is atomized with the
atomizing gas and is burned. Accordingly, even when the liquid fuel
is intermittently supplied from the liquid fuel supply tube to the
liquid fuel tank, the liquid fuel stored in the liquid fuel tank is
continuously discharged from the liquid fuel discharge holes of the
liquid fuel tank. In other words, even when the supply flow rate of
a pump of a liquid fuel supply system is low and the liquid fuel is
intermittently supplied from the liquid fuel supply tube to the
liquid fuel tank, the liquid level of the liquid fuel stored in the
liquid fuel tank fluctuates a little up and down to cause the flow
rate of the liquid fuel discharged from the one or plurality of
liquid fuel discharge holes to fluctuate a very little. The flow
rate of supplied liquid fuel does not fluctuate so much unlike the
conventional one. The liquid fuel can be therefore stably supplied
even when the flow rate of supplied liquid fuel is low, thus
achieving stable combustion is facilitated and the possibility of
producing unburned exhaust gas and causing accidental fire is
eliminated.
[0098] According to the two-fluid spray burner of the second
configuration, the liquid fuel which is discharged from the liquid
fuel discharge holes to flow into the two-fluid converging space
portion converges with the atomizing gas which flows down the
atomizing gas passage and passes through the grooves at the
atomizing gas introduction portion to be introduced into the
two-fluid converging space portion and is then sprayed from the
spray holes together with the atomizing air. Accordingly, the
liquid fuel is well mixed with the atomizing air whose the flow
speed is increased at the grooves (with the horizontal speed
component increased), at the two-fluid converging space portion and
is then sprayed from the spray holes of the two-fluid spray nozzle.
Compared to the case of not providing the two-fluid converging
space portion and grooves, therefore, the spread angle of the
sprayed liquid fuel is larger, and the liquid fuel is surely
atomized, thus improving the combustion characteristics of the
liquid fuel.
[0099] According to the two-fluid spray burner of the third
configuration, the liquid fuel tank is installed on the atomizing
gas introduction portion with the tapered surface portion of the
liquid fuel tank being abutted and fitted to the tapered surface
portion of the atomizing gas introduction portion. This facilitates
alignment of the central axes of the liquid fuel tank and two-fluid
spray nozzle. Accordingly, the liquid fuel tank is installed at the
center, and it is possible to equalize the width of the atomizing
gas passage in the circumferential direction and equalize the flow
of the atomizing gas in the atomizing gas passage in the
circumferential direction. This makes it possible to secure
symmetric properties of the liquid fuel sprayed from the spray hole
of the two-fluid spray nozzle (or symmetric properties of the
flame).
[0100] According to the two-fluid spray burner of the fourth
configuration, the liquid fuel which is discharged from the liquid
fuel discharge holes to flow into the two-fluid converging space
portion converges at the two-fluid converging space portion with
the atomizing gas which flows down the atomizing gas passage and
flows through the grooves at the bottom portion of the fuel tank to
be introduced into the two-fluid converging space portion and is
then sprayed through the spray holes together with the atomizing
gas. Accordingly, the liquid fuel is well mixed with the atomizing
gas whose flow speed increased at the grooves (with the horizontal
speed component increased), at the two-fluid converging space
portion and is then sprayed through the spray holes. Compared to
the case of not providing the two-fluid converging space portion
and grooves, therefore, the spread angle of the liquid fuel is
larger, and the liquid fuel is surely atomized, thus improving the
combustion characteristics of the liquid fuel.
[0101] Furthermore, the liquid fuel tank is installed on the
two-fluid spray nozzle with the tapered surface portion of the
liquid fuel tank being abutted and fitted to the tapered surface
portion of the two-fluid spray nozzle. This facilitates alignment
of the central axes of the liquid fuel tank and the two-fluid spray
nozzle. Accordingly, the liquid fuel tank is installed at the
center, and it is possible to equalize the width of the atomizing
gas passage in the circumferential direction and thus equalize the
flow of the atomizing gas in the atomizing gas passage in
circumferential direction. It is therefore possible to secure the
symmetric properties of the liquid fuel sprayed from the spray
holes of the two-fluid spray nozzle (or symmetric properties of
flame).
[0102] According to the two-fluid spray burner of the fifth
configuration, the grooves of the atomizing gas introduction
portion or the grooves of the bottom portion of the liquid fuel
tank are formed along tangent directions of the circumference of
the two-fluid converging space portion in a top view. Accordingly,
the atomizing gas is swirled and mixed with the liquid fuel at the
two-fluid converging space portion, and the liquid fuel and
atomizing gas are thus mixed more surely. The liquid fuel sprayed
through the spray hole of the two-fluid spray nozzle can be
therefore surely atomized, thus further improving the combustion
characteristics of the liquid fuel.
[0103] According to the two-fluid spray burner of the sixth
configuration, the grooves of the atomizing gas introduction
portion or the grooves of the bottom portion of the liquid fuel
tank are formed along the radial directions of the two-fluid
converging space portion in a top view. The atomizing gas therefore
collides with the liquid fuel at the two-fluid converging space
portion to be mixed with the liquid fuel, and the liquid fuel and
atomizing gas are more surely mixed. The liquid fuel sprayed from
the spray holes of the two-fluid spray nozzle can be atomized more
surely, thus further improving the combustion characteristics of
the liquid fuel.
[0104] According to the two-fluid spray burner of the seventh
configuration, the plurality of grooves of the atomizing gas
introduction portion or the plurality of grooves of the bottom
portion of the liquid fuel tank are formed at positions
rotationally symmetric around the central axis of the two-fluid
converging space portion. Accordingly, the distribution of the
liquid fuel sprayed from the spray holes of the two-fluid spray
nozzle can be equalized in the circumferential direction, thus
improving the combustion characteristics of the liquid fuel.
[0105] According to the two-fluid spray burner of the eighth
configuration, the two-fluid spray burner is provided with the
press member pressing the liquid fuel tank downward. The bottom
portion of the liquid fuel tank is thus pressed against the
atomizing gas introduction portion of the two-fluid spray nozzle to
be brought into firm contact with the same, or the bottom portion
of the liquid fuel tank is thus pressed against the two-fluid spray
nozzle to be brought into firm contact with the same. Accordingly,
the undersurface of the bottom portion of the fuel tank and the top
surface of the atomizing gas introduction portion are brought into
firm contact. In other words the tapered surface portion of the
liquid fuel tank and the tapered surface portion of the atomizing
gas introduction portion, or the tapered surface portion of the
liquid fuel tank and the tapered surface portion of the two-fluid
spray nozzle are brought into firm contact, thus preventing
formation of gap between these contact surfaces. It is therefore
possible to prevent the atomizing gas from flowing into a place
other than the grooves and sufficiently provide the effects of wide
spraying by the grooves.
[0106] According to a two-fluid spray burner of the ninth
configuration, the liquid fuel which is discharged from the liquid
fuel discharge holes to flow into the two-fluid converging space
portion converges at the two-fluid converging space portion with
the atomizing gas which flows down the first atomizing gas passage,
passes through the atomizing gas passages between the supporting
portions, and then flows thorough the second atomizing gas passage
to be introduced to the two-fluid converging space portion and is
then sprayed together with the atomizing gas from the one or
plurality of spray holes. Accordingly, the liquid fuel is mixed
with the atomizing gas at the two-fluid converging space portion
and is then sprayed from the spray holes of the two-fluid spray
nozzle. Compared to the case of not providing the two-fluid
converging space portion and grooves, therefore, the spread angle
of the sprayed liquid fuel is larger, and the liquid fuel is surely
atomized, thus improving the combustion characteristics of the
liquid fuel.
[0107] According to the two-fluid spray burner of the tenth
configuration, the two-fluid converging space portion is a reverse
conical shape, and the spray holes are formed at the vertex
position of the reverse conical space portion. Accordingly, the
liquid fuel and atomizing gas can be more surely mixed at the
two-fluid converging space portion. The liquid fuel sprayed from
the spray holes is more surely atomized, thus further improving the
combustion characteristics of the liquid fuel.
[0108] According to the two-fluid spray burner of the eleventh
configuration, the end portion of the liquid fuel supply tube is in
contact with the internal peripheral surface of the side potion of
the liquid fuel tank, so that the liquid fuel flows down the inner
peripheral surface even when a flow rate of the liquid fuel
discharged from the liquid fuel supply tube is low. It is therefore
possible to further stabilize the discharge of the liquid fuel from
the liquid fuel discharge holes. In other words, when the liquid
fuel falls in droplets, the liquid level of the liquid fuel stored
in the liquid fuel tank greatly fluctuates. In the case where the
liquid level is very low, there might be a case where the liquid
fuel discharge holes are temporarily exposed to stop the discharge
of the liquid fuel. However, allowing the liquid fuel to flow down
the inner peripheral surface of the liquid fuel tank can prevent
occurrence of such a disadvantage.
[0109] FIG. 1 is a longitudinal sectional view showing a structure
of a two-fluid spray burner according to Embodiment 1 of the
present invention.
[0110] FIG. 2 is a transverse sectional view taken along a line A-A
of FIG. 1.
[0111] FIG. 3 is a transverse sectional view taken along a line B-B
of FIG. 1.
[0112] FIG. 4(a) is an enlarged longitudinal sectional view showing
a two-fluid sprayer provided for the two-fluid spray burner of FIG.
1, and
[0113] FIG. 4(b) is a transverse sectional view taken along a line
C-C of FIG. 4(a).
[0114] FIG. 5(a) is an enlarged longitudinal sectional view showing
lower part of the two-fluid sprayer, and
[0115] FIG. 5(b) is a top view (a view in the direction of arrows D
of FIG. 5 (a)) showing a two-fluid spray nozzle provided for the
two-fluid sprayer.
[0116] FIG. 6(a) is a longitudinal sectional view showing a
structure of lower part of a two-fluid sprayer in a two-fluid spray
burner according to Embodiment 2 of the present invention, and
[0117] FIG. 6(b) is a top view (a view in the direction of arrows E
of FIG. 6(a)) showing a two-fluid spray nozzle provided for the
two-fluid sprayer.
[0118] FIG. 7(a) is a longitudinal sectional view showing a
structure of lower part of a two-fluid sprayer in a two-fluid spray
burner according to Embodiment 3 of the present invention, and
[0119] FIG. 7(b) is a top view (a view in the direction of arrows F
of FIG. 7(a)) showing a two-fluid spray nozzle provided for the
two-fluid sprayer.
[0120] FIG. 8(a) is a longitudinal sectional view showing a
structure of lower part of a two-fluid sprayer in a two-fluid spray
burner according to Embodiment 4 of the present invention (a
longitudinal section view taken along the G-G line of FIG.
8(b));
[0121] FIG. 8(b) is a bottom view (a view in the direction of an
arrow H of FIG. 8(a)) showing a liquid fuel tank provided for the
two-fluid sprayer;
[0122] FIG. 8(c) is a view in the direction of an arrow I of FIG.
8(b); and
[0123] FIG. 8(d) is a transverse sectional view taken along a line
J-J of FIG. 8(a).
[0124] FIG. 9(a) is a longitudinal sectional view showing a
structure of lower part of a two-fluid sprayer in a two-fluid spray
burner according to Embodiment 5 of the present invention (a
cross-sectional view taken along a line K-K of FIG. 9(b));
[0125] FIG. 9(b) is a bottom view (a view in the direction of an
arrow L of FIG. 9(a)) showing a liquid fuel tank provided for the
two-fluid sprayer; and
[0126] FIG. 9(c) is a transverse sectional view taken along a line
M-M of FIG. 9(a).
[0127] FIG. 10(a) is a longitudinal sectional view showing a
structure of lower part of a two-fluid sprayer in a two-fluid spray
burner according to Embodiment 6 of the present invention.
[0128] FIG. 10(b) is a transverse sectional view taken along a line
L-L of FIG. 10(b).
[0129] FIG. 11 is a longitudinal sectional view showing
configuration of a two-fluid spray burner according to Embodiment 7
of the present invention.
[0130] FIG. 12 is a transverse sectional view taken along a line
0-0 of FIG. 11.
[0131] FIG. 13(a) is a view showing liquid fuel intermittently
discharged from an end of a liquid fuel supply tube in a
conventional two-fluid spray burner, and
[0132] FIG. 13(b) is a view showing great fluctuations in flow rate
of supplied liquid fuel in the conventional two-fluid spray
burner.
[0133] FIG. 14(a) is a longitudinal sectional view showing a
structure of a two-fluid spray burner according to Embodiment 8 of
the present invention, and
[0134] FIG. 14(b) is a transverse sectional view taken along a line
P-P of FIG. 14(a).
[0135] FIG. 15 is a graph showing a relation between a ratio (L/D)
and an optimal setting position of the throttle plate, (L) being a
distance between the spray hole of the two-fluid sprayer and a
throttle plate, and (D) being a diameter of the combustion space
portion
[0136] FIG. 16(a) is a longitudinal sectional view showing a
structure of a two-fluid spray burner according to Embodiment 9 of
the present invention; FIG. 16(b) is a transverse sectional view
taken along a line Q-Q of FIG. 16(a); and FIG. 16(c) is a
transverse sectional view corresponding to FIG. 16(b) showing
another structure example of swirling blades.
[0137] FIG. 17(a) is a longitudinal sectional view showing a
structure of a two-fluid spray burner according to Embodiment 10 of
the present invention; and FIG. 17(b) is a transverse sectional
view taken along a line R-R of FIG. 17(a).
[0138] FIG. 18 is a system diagram schematically showing a fuel
cell power generation system according to Embodiment 11 of the
present invention.
EXPLANATION OF REFERENCE NUMERALS
[0139] 11, TWO-FLUID SPRAY BURNER; 12, TWO-FLUID SPRAYER; 13,
COMBUSTION SPACE; 14, GAS FUEL PASSAGE; 15, COMBUSTION AIR PASSAGE;
16, FIRST CYLINDER; 17, SECOND CYLINDER; 18, PLATE; 19, LIQUID FUEL
TANK; 20, SIDE PORTION, 20a, INNER PERIPHERAL SURFACE; 20b, OUTER
PERIPHERAL SURFACE; 21, BOTTOM PORTION; 21a, INNERSURFACE (TOP
SURFACE); 21b, OUTERSURFACE (UNDERSURFACE); 21b-1, OUTSIDE PORTION;
21b-2, INSIDE PORTION; 22, LIQUID FUEL DISCHARGEHOLE; 23,
LIQUIDLEVEL; 24, LIQUIDFUEL; 24A, CONTOUR; 25, LIQUID FUEL SUPPLY
TUBE; 25A, END PORTION (BOTTOM END); 26, WASHER; 27,
SPRAYEROUTERCYLINDER; 27A, LOWEREND PORTION; 27B, UPPER END
PORTION; 28, ATOMIZING AIR PASSAGE; 29, AIR INLET HOLE; 30,
ATOMIZING AIR SUPPLY TUBE; 30A, END PORTION; 31, CAP; 32, 33,
THREAD PORTION; 31A, LOWER PORTION; 31B, STEP PORTION; 34, O-RING;
35, WASHER; 36, COIL SPRING; 37, ATOMIZING GAS INTRODUCTION
PORTION; 37a, TOP SURFACE; 37b, INNER PERIPHERAL SURFACE; 38,
TWO-FLUID SPRAY NOZZLE; 38a, INNER SURFACE (TOP SURFACE); 39,
NOZZLE BODY; 40, GROOVE; 41, SPACE; 42 SPACE (RECESS); 43,
TWO-FLUID CONVERGING SPACE PORTION; 44, SPRAY HOLE; 45, GAP; 46,
ATOMIZING AIR; 47, GAS FUEL SUPPLY TUBE; 48, BURNER OUTER CYLINDER;
48a, INNER PERIPHERAL SURFACE; 49, GAS FUEL; 50, COMBUSTION AIR;
51, PROTRUSION; 52, COMBUSTION AIR PASSAGE HOLE; 53, COMBUSTION AIR
PASSAGE; 54, SPARK PLUG; 61, GROOVE; 81, GROOVE; 91, SUPPORT
PORTION; 91a, UNDERSURFACE; 91a-1, OUTSIDE PORTION; 92, ATOMIZING
AIR PASSAGE; 93, ATOMIZING AIR PASSAGE PORTION; 101, COMBUSTION AIR
PASSAGE HOLE; 111, REFORMER; 112, COMBUSTION FURNACE; 113 FUEL
CELL; 121, THROTTLE PLATE; 122, PASSAGE HOLE; 123, FLAME; 124,
SWIRLING BLADE; 125, POROUS PLATE; 126, HOLE; 127, PASSAGE HOLE
BEST MODES FOR CARRYING OUT THE INVENTION
[0140] Hereinafter, a description is given of embodiments of the
present invention with reference to the drawings.
Embodiment 1
[0141] FIG. 1 is a longitudinal sectional view showing a
configuration of a two-fluid spray burner according to Embodiment 1
of the present invention. FIG. 2 is a transverse sectional view
taken along a line A-A of FIG. 1. FIG. 3 is a transverse sectional
view taken along a line B-B of FIG. 1. FIG. 4(a) is an enlarged
longitudinal sectional view showing a two-fluid sprayer provided in
the two-fluid spray burner of FIG. 1, and FIG. 4(b) is a transverse
sectional view taken along a line C-C of FIG. 4(a). FIG. 5(a) is an
enlarged longitudinal sectional view showing lower part of the
two-fluid sprayer, and FIG. 5(b) is a top view (a view in the
direction of arrows D) showing a two-fluid spray nozzle provided
for the two-fluid sprayer.
[0142] Based on FIGS. 1 to 3, a schematic description is given of a
two-fluid spray burner 11 of Embodiment 1. The two-fluid spray
burner 11 includes a burner outer cylinder 48. Within the burner
outer cylinder 48, a two-fluid sprayer 12 is placed in upper
central part, and a combustion space 13 is under the two-fluid
sprayer 12. A gas fuel supply passage 14 is formed around the
two-fluid sprayer 12, and around the gas fuel supply passage 14, a
combustion air supply passage 15 is formed. The combustion air
supply passage 15 and combustion space 13 are partitioned with a
plate 18 as a shielding plate. On an undersurface of the plate 18,
a first cylinder 16 as a cylinder for delaying supply of combustion
air and a second cylinder 17 as a cylinder for preventing
stagnation are provided.
[0143] Based on FIGS. 4 and 5, a description is given of a
configuration of the two-fluid sprayer 12 in detail. Note that, the
two-fluid sprayer 12 sprays two fluids which are liquid fuel and
atomizing gas (atomizing air), in other words, atomizes the liquid
fuel with atomizing gas and sprays the same.
[0144] As shown in FIGS. 4 and 5, the two-fluid sprayer 12 has a
liquid fuel tank 19 built-in. The liquid fuel tank 19 has a
structure including a cylindrical side portion (a body portion) 20
and a bottom portion 21 provided at a bottom end of the side
portion 20. Within the liquid fuel tank 19, liquid fuel 24 for
burner combustion is stored, and a fine liquid fuel discharge hole
22 is opened at the center of the bottom portion 21 of the liquid
fuel tank 19. The liquid fuel discharge hole 22 is positioned below
a liquid level 23 of the liquid fuel 24 stored in the liquid fuel
tank 19.
[0145] Specifically, the liquid fuel 24 supplied from a liquid fuel
supply tube 25 is once stored in the liquid fuel tank 19. The
stored liquid fuel 24 is discharged from the liquid fuel tank 19
through the liquid fuel discharge hole 22 at the bottom. At this
time, height of the liquid level 23 of the liquid fuel 24 stored in
the liquid fuel tank 19 (height from an inner surface 21a of the
bottom portion 21 to the liquid level 23) is a height which
provides a liquid column head (described in detail later)
corresponding to a pressure loss of the liquid fuel 24 flowing
through the liquid fuel discharge hole 22. Examples of the liquid
fuel 24 for burner combustion can be kerosene, heavy oil, alcohol,
ether and the like.
[0146] In the liquid fuel supply tube 25, an end portion (a lower
end portion) 25A is inserted downward from an upper end of the
liquid fuel tank 19 into the liquid fuel tank 19 and is provided to
be positioned in central part of the liquid fuel tank 19 above the
liquid level 23. The base end of the liquid fuel supply tube 25 is
connected to a liquid fuel supply pump of an unillustrated liquid
fuel supply system.
[0147] As indicated by a dashed-dotted line in FIG. 5(a), the end
portion 25A of the liquid fuel supply tube 25 may be in contact
with an inner peripheral surface 20a of the side portion 20 of the
liquid fuel tank 19. When the liquid fuel 24 is supplied at a low
flow rate, the liquid fuel 24 drops in droplets as illustrated in
the drawing, if the end portion 25A of the liquid fuel supply tube
25 is spaced from the inner peripheral surface 20a of the liquid
fuel tank 19. On the other hand, the liquid fuel 24 flows down the
inner peripheral surface 20a, if the end portion 25A of the liquid
fuel supply tube 25 is in contact with the inner peripheral surface
20a of the liquid fuel tank 19.
[0148] The liquid fuel tank 19 is provided within the cylindrical
sprayer outer cylinder 27 in a concentric manner with the sprayer
outer cylinder 27. In the liquid fuel tank 19, cylindrical space
between the side portion 20 and sprayer outer cylinder 27 is an
atomizing air passage 28 serving as an atomizing air passage. In
the sprayer outer cylinder 27, an air inlet hole 29 is opened. The
air inlet hole 29 is connected to an end portion 30A of the
atomizing air supply tube 30. The base side of the atomizing air
supply tube 30 is connected to an air supply blower of an
unillustrated atomizing air supply system.
[0149] The two-fluid spray nozzle 38 is attached to a lower end
portion 27A of the sprayer outer cylinder 27 and positioned under
the liquid fuel tank 19. In other words, the two-fluid sprayer 12
is configured to include the liquid fuel tank 19, as a buffer for
reducing fluctuations in flow rate of supplied fuel liquid,
interposed between the liquid fuel supply tube 25 and two-fluid
spray nozzle 38. The two-fluid spray nozzle 38 includes a
disk-shaped nozzle body 39 and an atomizing air introduction
portion 37 formed on the nozzle body 39 as an atomizing gas
introduction portion. The two-fluid spray nozzle 38 is fixed to the
lower end portion 27A of the sprayer outer cylinder 27 by fixing
means such as welding, with the peripheral edge of the top surface
of the nozzle body 39 abutted on the lower end surface of the
sprayer outer cylinder 27 and with the atomizing air introduction
portion 37 fitted into the lower end portion 27A of the sprayer
outer cylinder 27.
[0150] The atomizing air introduction portion 37 is formed into a
ring-shape and includes a space 41 with a circular plan view (top
view) in the central part. The nozzle body 39 includes a reverse
conical space (recess) 42 in the central part and a fine spray hole
44 opened at the center (at a vertex position of the reverse
conical space 42). The space 41 of the atomizing air introduction
portion 37 is continuous to the space 42 of the nozzle body 39, and
the spaces 41 and 42 constitute a two-fluid converging space
portion 43. Specifically, the two-fluid converging space portion 43
has a tapered structure with a circular top view and a diameter
gradually reducing towards the spray hole 44. In the atomizing air
introduction portion 37, grooves (slits) 40 are formed at two
places in the circumference direction thereof. These grooves 40 are
swirling type and are extended in tangent directions of the
circumference of the two-fluid converging space portion 43 in a top
view. Moreover, the grooves 40 are formed at positions rotationally
symmetric (at equal intervals in the circumferential directions)
around a central axis of the two-fluid converging space portion 43
(a central axis of the spray hole 44 in the example of the
drawing).
[0151] On the other hand, the upper end portion 27B of the sprayer
outer cylinder 27 is closed with a cap 31 as a closing member to
prevent leak of the atomizing air from the inside of the sprayer
outer cylinder 27 to the outside. The cap 31 is attached to the
upper end portion 27B of the sprayer outer cylinder 27 by screwing
a thread portion 33 formed in an outer peripheral surface of a
lower portion 31A of the cap 31 to a thread portion 32 formed in an
inner peripheral surface of the upper end portion 27B of the
sprayer outer cylinder 27. Between a step portion 31B of the cap 31
and the upper end portion 27B of the sprayer outer cylinder 27, an
O ring 34 is interposed to reliably prevent leak of the atomizing
air. The end portion 25A of the liquid fuel supply tube 25
penetrates through the cap 31, passes through the inside of the
sprayer outer cylinder 27 (the inside of a coil spring 36), and
then inserted into the liquid fuel tank 19 through an upper end of
the liquid fuel tank 19.
[0152] Between a washer 35 provided on an undersurface of the cap
31 and a washer 26 provided on an upper end of the liquid fuel tank
19, the coil spring 36 as a press member is interposed. The coil
spring 36 presses the liquid fuel tank 19 downward to press an
outer surface (undersurface) 21b of the bottom portion 21 of the
liquid fuel tank 19 against the top surface 37a of the atomizing
air introduction portion 37. Accordingly, the outer surface
(undersurface) 21b of the bottom portion 21 and top surface 37a of
the two-fluid nozzle 38 (atomizing air introduction portion 37) in
contact with each other are firmly joined to each other, thus
preventing formation of gap between these contact surfaces 21b and
37a.
[0153] Between the washer 26 and liquid fuel supply tube 25, a gap
45 is provided, through which internal space of the liquid fuel
tank 19 and internal space of the sprayer outer cylinder 27 outside
of the liquid fuel tank 19 communicate with each other. In other
words, the upper end of the liquid fuel tank 19 is opened to the
internal space of the sprayer outer cylinder 27, and the internal
space of the liquid fuel tank 19 and the upper end portion
(upstream portion) of the atomizing air passage 28 communicate with
each other. Accordingly, pressure of atomizing air 46 flowing from
the air inlet hole 29 into the sprayer outer cylinder 27 and then
into the atomizing air passage 28 acts on the liquid level 23 of
the liquid fuel 24 stored in the liquid fuel tank 19.
[0154] In this two-fluid sprayer 12, when the liquid fuel 24 for
burner combustion which is fed from the liquid fuel supply pump
through the liquid fuel supply tube 25 is discharged from the end
portion 25A of the liquid fuel supply tube 25 (discharged
continuously in the case of comparatively high flow rate and
intermittently discharged in the case of comparatively low flow
rate as illustrated in FIG. 5(a)), the liquid fuel 24 is once
stored in the liquid fuel tank 19. The liquid fuel 24 stored in the
liquid fuel tank 19 is continuously discharged from the liquid fuel
discharge hole 22 of the bottom portion 21 of the liquid fuel tank
19 into the two-fluid converging space portion 43. In the case
where the liquid fuel is intermittently discharged from the end
portion 25A of the liquid fuel supply tube 25, a phenomenon is
repeated in which the liquid level 23 rises while the liquid fuel
24 is discharged from the endportion 25A of the liquid fuel supply
tube 25 and falls while the liquid fuel 24 is not discharged from
the end portion 25A of the liquid fuel supply tube 25. Though the
flow rate of the liquid fuel 24 discharged from the liquid fuel
discharge hole 22 varies according to such fluctuations in liquid
level, such variations in flow rate are much smaller than the
conventional variations in flow rate.
[0155] On the other hand, the atomizing air 46 fed from an air
supply pump through the atomizing air supply tube 30 flows into the
sprayer outer cylinder 27 through the air inlet hole 29 and flows
down the atomizing air passage 28 between the liquid fuel tank 19
and sprayer outer cylinder 27. Thereafter, the atomizing air 46
flows through the grooves 40 of the atomizing air introduction
portion 37 of the two-fluid spray nozzle 38 to increase flow rate
and is then introduced to the two-fluid converging space portion
43. The atomizing air 46 becomes swirling flow in the two-fluid
converging space portion 43 and converges with (is mixed with) the
liquid fuel 24 discharged from the liquid fuel discharge hole 22 of
the liquid fuel tank 19. The liquid fuel 24 is therefore well mixed
with the atomizing air 46 and is atomized with the atomizing air 46
to be sprayed together with the atomizing air 46 from the spray
hole 44 of the two-fluid spray nozzle 38 into a combustion space 13
(flame) for combustion. The initial ignition to the atomized liquid
fuel 24 is performed by a spark plug 54.
[0156] Herein, the liquid column head H of the liquid fuel 24
stored in the liquid fuel tank 19 is described in detail. The
liquid column head H can be calculated by the following equation
based on a pressure loss .DELTA.P (hole) of the liquid fuel 24
flowing through the liquid fuel discharge hole 22, a kinetic energy
E of the liquid fuel 24 discharged from the liquid fuel discharge
hole 22, and a pressure loss APair of the atomizing air 49 at the
grooves 40.
Liquid Column Head H=Pressure Loss .DELTA.P (hole)+Kinetic Energy
E-Pressure Loss .DELTA.Pair
[0157] The kinetic energy E can be calculated by the following
equation based on flow velocity v of the liquid fuel 24 and density
.rho. of the liquid fuel 24.
Kinetic Energy=.rho.v.sup.2/2
[0158] Moreover, the height of the liquid level 23 of the liquid
fuel 24 stored in the liquid fuel tank 19 varies with the flow rate
of the liquid fuel 24 supplied to the liquid fuel tank 19 through
the liquid fuel supply tube 25. In other words, the liquid level 23
rises when the output of the fuel supply pump is controlled to
increase the flow rate of the liquid fuel 24 supplied and falls
when the flow rate of the liquid fuel 24 is reduced. Accordingly,
the liquid fuel tank 19 is configured to have a height
corresponding to changes in height of the liquid level 23 according
to a predetermined regulation range of the flow rate of the
supplied liquid fuel 24.
[0159] Moreover, the liquid fuel 24 is sprayed in a cone shape from
the spray hole 44 as illustrated in FIG. 5(a). The spread of the
spray (spray angle) is determined by a cross-sectional area of the
grooves 40 (or flow speed of the atomizing air 46 flowing through
the grooves 40), size of the spray hole 44 (or hole diameter), and
the like.
[0160] Next, a description is given of the configuration other than
the two-fluid sprayer 12 in detail. As shown in FIGS. 1 to 3, a
cylindrical gas fuel supply tube 47 is provided so as to surround
the periphery of the sprayer outer cylinder 27. The gas fuel supply
tube 47 is concentrically provided with the sprayer outer cylinder
27, and cylindrical space between the gas fuel supply tube 47 and
sprayer outer cylinder 27 is a gas fuel passage 14. Gas fuel 49 for
burner combustion supplied from a gas fuel supply system flows down
the gas fuel passage 14 to be sprayed from the lower end of the gas
fuel passage 14 into the combustion space 13 for combustion. The
liquid fuel 24 and the gas fuel 49 may be burned separately or
simultaneously. Examples of the gas fuel 49 for burner combustion
are methane, ethane, propane, butane, diethyl ether, and hydrogen.
Furthermore, in the case of using the two-fluid spray burner 11 as
a heat source of a reformer, the gas fuel 49 may be residual
reformed gas not used for power generation in a fuel cell and
returned to the two-fluid spray burner 11 (see FIG. 13).
[0161] The burner outer cylinder 48 is cylindrical and surrounds
the periphery of the gas fuel supply tube 47. The burner outer
cylinder 48 and gas fuel supply tube 47 are provided
concentrically, and cylindrical space between the burner outer
cylinder 48 and gas fuel supply tube 47 is a first combustion air
passage 15. Accordingly, the combustion air 50 supplied from an air
supply blower of the combustion air supply system flows down the
combustion air passage 15.
[0162] Between the lower end portion of the combustion air passage
15, that is a lower end portion of the gas fuel supply tube 47, and
the lower end portion of the burner outer cylinder 48, a plate 18
is provided. The plate 18 is a ring-shaped plate and separates the
combustion air passage 15 and combustion space 13. In the example
of the drawings, the plate 18 is provided at substantially the same
height as that of the two-fluid spray nozzle 38, but it is not
limited to this and may be provided at a position higher than that
of the two-fluid spray nozzle 38. However, if the plate 18 is
provided at a higher position, the first and second cylinders 16
and 17 need to be made longer than those of the example of the
drawing. Accordingly, providing the plate 18 at the same height as
that of the two-fluid spray nozzle 38 like the example of the
drawing costs the least, which is reasonable.
[0163] The inner peripheral surface of the plate 18 is fixed to the
outer peripheral surface of the gas fuel supply tube 47 by fixing
means such as welding. In the outer peripheral surface of the plate
18, a plurality of protrusions 51 (four protrusions in the example
of FIG. 2) are formed. End surfaces of the protrusions 51 are fixed
to the inner peripheral surface of the burner outer cylinder 48 by
fixing means such as welding. Accordingly, part between the gas
fuel supply tube 47 and the vicinity of the burner outer cylinder
48 is closed by the plate 18. However, on the outer periphery of
the plate 18, gaps are formed between the outer peripheral surface
of the plate 18 and the inner peripheral surface 48a of the burner
outer cylinder by the protrusions 51. These gaps are combustion air
holes 52. In other words, the combustion air passage 15 and
combustion space 13 communicate with each other through these
combustion air holes 52.
[0164] Accordingly, after flowing down the combustion air passage
15, the combustion air 50 is blocked by the plate 18 to be
introduced to the outer peripheral side of the plate 18, which is
away from the two-fluid spray nozzle 38 (spray hole 44) and flows
through the combustion air holes 52 into the combustion space
13.
[0165] Moreover, the first cylinder 16 extending downward and the
second cylinder 17 extending downward, the second cylinder 17 being
provided inside the first cylinder 16, are fixed to the
undersurface of the plate 18 by fixing means such as welding. The
first cylinder 16 is located in a position inner to the combustion
air holes 52 and arranged concentrically with the burner outer
cylinder 48. The cylindrical space between the burner outer
cylinder 48 and the first cylinder 16 is a second combustion air
passage 53.
[0166] Accordingly, after flowing down the first combustion air
passage 15 and passing through the combustion air hole 52, the
combustion air 50 further flows down the second combustion air
passage 53. The combustion air 50 is discharged from the lower end
of the combustion air passage 53 and spreads over the combustion
space 13. Accordingly, a part of the combustion air 50 discharged
from the combustion air passage 53 (for example, about 30% of the
entire combustion air 50) is supplied to (mixed with) the liquid
fuel 24 sprayed from the two-fluid sprayer 12 (the two-fluid spray
nozzle 38) at a position downward away from the plate 18 and used
in combustion of the liquid fuel 24. The amount of the combustion
air 50 mixed with the liquid fuel 24 is set so that an average of
the air ratio is not more than 1.5, for example. The residual of
the combustion air 50 discharged from the combustion air passage 53
(for example, about 70% of the entire combustion air 50) further
flows down and is mixed with combustion exhaust gas produced by the
combustion, thus producing a large amount of combustion exhaust
gas.
[0167] The first cylinder 16 is installed for the purpose of
delaying supply of a part of the combustion air 50 to the atomized
liquid fuel 24, that is, supplying the combustion air 50 to the
atomized liquid fuel 24 at the position downward away from the
plate 18. Thus, the plate 18 is kept away of the flame and
prevented from being sooted. The length of the first cylinder 16,
that is the end position (bottom end) of the first cylinder 16 may
be properly set based on a relation with size of the plate 18
(distance between the spray hole 44 of the two-fluid spray nozzle
38 and the combustion air hole 52).
[0168] In other words, even without the first cylinder 16 but only
with the plate 18 and the combustion air hole 52 in the outer
periphery of the plate 18, a part of the combustion air 50 passed
through the combustion air hole 51 is supplied to the atomized
liquid fuel 24 at a position downward away from the plate 18. The
longer the distance between the spray hole 44 and the combustion
air hole 52 is, the farther, from the plate 18, the position where
the part of the combustion air 50 is supplied to the atomized
liquid fuel 24 is. If the plate 18 is increased in size to increase
the distance between the spray hole 44 and the combustion air hole
52, the two-fluid spray burner 11 is increased in diameter.
[0169] On the other hand, when the distance between the spray hole
44 and the combustion air hole 52 is limited by the limitation in
size of the two-fluid spray burner 11, the supply of the part of
the combustion air 50 to the atomized liquid fuel 24 cannot be
delayed enough in some cases only by providing the plate 18 and
combustion air hole 51. In such a case, provision of the first
cylinder 16 as illustrated in the drawing is very effective. In
this case, as the distance between the spray hole 44 and the
combustion air hole 52 is reduced, the first cylinder 16 is
extended downward. However, to prevent interference between the
first cylinder 16 and sprayed liquid fuel 24, the end (lower end)
of the first cylinder 16 needs to be positioned outside of (above)
a contour 24A of the sprayed liquid fuel 24. In other words, the
end (lower end) of the first cylinder 16 cannot be extended more
than the contour 24A of the sprayed liquid fuel 24.
[0170] If the distance between the spray hole 44 and the combustion
air hole 52 is reduced, the installation position of the first
cylinder 16 becomes closer to the spray hole 44, and the distance
between the plate 18 and contour 24A of the atomized liquid fuel 24
is reduced. The first cylinder 16 therefore cannot be made so long.
The distance between the spray hole 44 and the combustion air hole
52 and the length of the first cylinder 16 (including necessity of
the first cylinder 16) may be properly determined in view of such
restrictions.
[0171] The second cylinder 17 is positioned inside the first
cylinder 16 and is provided concentrically with the first cylinder
16. The second cylinder 17 is provided for the purpose of
preventing stagnation (convection) of the atomized liquid fuel 24
from occurring near the plate 18. Thus, the plate 18 is kept away
of the flame and prevented from being sooted. Accordingly, the
second cylinder 17 is extended downward as much as possible.
However, to prevent interference between the second cylinder 17 and
atomized liquid fuel 24, the end (lower end) of the second cylinder
17 needs to be positioned outside of (above) the contour 24A of the
atomized liquid fuel 24. In other words, the end (lower end) of the
second cylinder 17 also can only be extended to the contour 24A of
the atomized liquid fuel 24 at maximum.
[0172] For example, as shown in FIG. 1, length L2 between the end
(bottom end) of the two-fluid spray nozzle 38 (spray hole 44) and
the end (bottom end) of the second cylinder 17 needs to satisfy
0<L2<L1 tan .theta.. Herein, L1 is the distance between the
spray hole 44 of the two-fluid spray nozzle 38 and the second
cylinder 17, and .theta. is an angle between the contour 24A of the
sprayed liquid fuel 24 and the horizontal line thereof. The entire
length of the second cylinder 17 is L2 added to length between the
undersurface of the plate 18 and the end (lower end) of the
two-fluid spray nozzle 38 (spray hole 44). Such a condition is also
applied to length between the end (lower end) of the two-fluid
spray nozzle 38 (spray hole 44) and the end (lower end) of the
first cylinder 16 and the entire length of the first cylinder 16.
The distance between the spray hole 44 of the two-fluid spray
nozzle 38 and the second cylinder 16 is configured to be for
example, not less than 50 or 60 times the diameter of the spray
hole 44 (about 1 mm, for example).
[0173] As described above, the two-fluid spray burner 11 of present
Embodiment 1 is provided with the liquid fuel tank 19 which
includes the cylindrical side portion 20 and the bottom portion 21
provided at the lower end of the side portion 20 and stores the
liquid fuel 24 supplied from the liquid fuel supply tube 25. The
liquid fuel tank 19 is configured to allow the stored liquid fuel
24 to be discharged from the liquid fuel discharge hole 22, in the
bottom portion 21, which is opened below the liquid level of the
stored liquid fuel 24. The liquid fuel 24 discharged from the
liquid fuel discharge hole 22 of the liquid fuel tank 19 is
atomized with the atomizing air 46 and is burned. Accordingly, even
when the liquid fuel 24 is intermittently supplied from the liquid
fuel supply tube 24 to the liquid fuel tank 19, the liquid fuel
stored in the liquid fuel tank 19 is continuously discharged from
the liquid fuel discharge hole 22 of the liquid fuel tank 19. In
other words, even when the supply flow rate of the pump of the
liquid fuel supply system is reduced and the liquid fuel 24 is
intermittently supplied from the liquid fuel supply tube 25 to the
liquid fuel tank 19, the liquid level 23 of the liquid fuel 24
stored in the liquid fuel tank 19 fluctuates just a little up and
down and only causes the flow rate of the liquid fuel 24 discharged
from the liquid fuel discharge hole 22 to fluctuate a little. The
flow rate of supplied liquid fuel does not fluctuate as much as the
conventional one as shown in FIG. 13. It is therefore possible to
stably supply the liquid fuel 24 even if the flow rate of the
liquid fuel supplied is low, thus facilitating achievement of
stable combustion and eliminating the possibility of producing
unburned exhausted gas and causing accidental fire.
[0174] According to the two-fluid spray burner 11 of Embodiment 1,
the two-fluid spray burner 11 is configured so that the liquid fuel
22 discharged from the liquid fuel discharge hole 22 and flown into
the two-fluid converging space portion 43 converges with the
atomizing air flowing down the atomizing air passage 28 and flown
through the grooves 40 at the atomizing air introduction portion 37
to be introduced into the two-fluid converging space portion 43 and
then sprayed from the spray hole 44 together with the atomizing
air. Accordingly, the liquid fuel 24 is well mixed with the
atomizing air 46 with the flow speed increased at the grooves 40
(with the horizontal speed component increased) at the two-fluid
converging space portion 43 and then sprayed from the spray hole 44
of the two-fluid spray nozzle 38. Compared to the case of not
providing the two-fluid converging space portion 43 and grooves 40,
therefore, the spread angle of the liquid fuel 24 is larger, and
the liquid fuel 24 is surely atomized, so that the combustion
quality is improved.
[0175] According to the two-fluid spray burner 11 of Embodiment 1,
the grooves 40 of the atomizing air introduction portion 37 are
formed along the tangent directions of the circumference of the
two-fluid converging space portion 43 in a top view. Accordingly,
the atomizing air 46 is swirled and mixed with the liquid fuel 24
at the two-fluid converging space portion 43. The liquid fuel 24
and atomizing air 46 are therefore mixed more surely. The liquid
fuel 24 sprayed from the spray hole 44 of the two-fluid spray
nozzle 38 can be therefore more surely atomized, and the combustion
quality of the liquid fuel 24 can be further improved.
[0176] According to the two-fluid spray burner 11 of Embodiment 1,
the plurality of grooves 40 of the atomizing air introduction
portion 37 are formed at positions rotationally symmetric around
the central axis of the two-fluid converging space portion 43.
Accordingly, the circumferential distribution of the liquid fuel 24
sprayed from the spray hole 44 of the two-fluid spray nozzle 38 can
be equalized, and thus improving the combustion characteristics of
the liquid fuel 24.
[0177] Moreover, the two-fluid spray burner 11 of Embodiment 1 is
provided with the coil spring 36 pressing the liquid fuel tank 19
downward. The bottom portion 21 of the liquid fuel tank 19 is
therefore pressed against the atomizing air introduction portion 37
of the two-fluid spray nozzle 38 to be brought into firm contact.
Accordingly, the undersurface 21b of the bottom portion 21 of the
fuel tank 19 and the top surface 37a of the atomizing air
introduction portion 37 are firmly in contact to each other to
prevent gap between these contact surfaces 21b and 37a. It is
therefore possible to prevent the atomizing air 46 from flowing
into portion other than the grooves 40 and allow the effect of wide
spray by the grooves 40 to be sufficiently exerted.
[0178] Moreover, according to the two-fluid spray burner 11 of
Embodiment 1, the two-fluid converging space portion 43 is reversed
conical, and the spray hole 44 is formed at the vertex position of
the reverse conical space 43. Accordingly, the liquid fuel 24 and
atomizing air 46 can be surely mixed at the two-fluid converging
space portion 43. The liquid fuel 24 to be sprayed from the spray
hole 44 is more surely atomized, thus further improving the
combustion characteristics of the liquid fuel 24.
[0179] Moreover, according to the two-fluid spray burner 11 of
Embodiment 1, the two-fluid spray burner 11 is configured so that
the cylindrical gas fuel passage 14 is formed between the sprayer
outer cylinder 27 and the gas fuel supply tube 47 surrounding the
sprayer outer cylinder 27 and allows the gas fuel 49 to flow down
the gas fuel passage 14 to be sprayed from the lower end of the gas
fuel passage 14 and burned. Accordingly, the gas fuel 49 sprayed
from the cylindrical gas fuel passage 14 is circumferentially
uniform. It is therefore possible to improve the combustion
characteristics, thus achieving a flame holding effect by the gas
fuel 49 when the liquid fuel 24 is supplied at a low flow rate, for
example.
[0180] Moreover, in the two-fluid spray burner 11 of Embodiment 1,
in the case where the end portion 25A of the liquid fuel supply
tube 25 is in contact with the internal peripheral surface 20a of
the side potion 20 of the liquid fuel tank 19, the liquid fuel 24
flows down the internal peripheral surface 20a even when the flow
rate of the liquid fuel 24 discharged from the liquid fuel supply
tube 25 is low. It is therefore possible to achieve more stable
discharge of the liquid fuel 24 from the liquid fuel discharge hole
22. In other words, when the liquid fuel 24 falls in droplets, the
liquid level 23 of the liquid fuel 24 stored in the liquid fuel
tank 19 greatly fluctuates. In the case where the liquid level 23
is very low, it can be thought that the liquid fuel discharge hole
22 is temporarily exposed and discharge of the liquid fuel 24 is
stopped. However, allowing the liquid fuel 24 to flow down along
the inner peripheral surface 20a of the liquid fuel tank 19 can
prevent occurrence of such a disadvantage.
[0181] Furthermore, according to the two-fluid spray burner 11 of
Embodiment 1, the two-fluid spray burner 11 is configured so that
after flowing down the combustion air passage 15, the combustion
air 50 is blocked by the plate 18 and is introduced to the outer
peripheral side of the plate 18, away from the two-fluid spray
nozzle 38, to flow through the combustion air hole 52 into the
combustion space 13. Accordingly, only a part of the combustion air
50 is mixed with the liquid fuel 24 sprayed from the two-fluid
spray nozzle 38 at the combustion space 13 and used in combustion
of the liquid fuel 24, and the residual of the combustion air 50
further flows down and is mixed with the combustion exhausted gas
produced by the combustion. It is therefore possible to achieve
proper mixture of the combustion air 50 and liquid fuel 24 through
one supply of the combustion air (one step) and produce a large
amount of combustion exhaust gas without exceedingly cooling flame.
In other words, it is possible to achieve a two-fluid spray burner
which is capable of producing a large amount of combustion exhaust
gas with a simple configuration and does not cause generation of
unburned gas and accidental fire.
[0182] Moreover, the combustion air 50 is caused by the plate 18 to
flow into the combustion space 13 at the position away from the
two-fluid spray nozzle 38. Accordingly, the position where a part
of the combustion air 50 is supplied to fuel can be set downward
away from the plate 18. The position of flame is therefore downward
away from the plate 18, thus preventing adherence of soot to the
undersurface of the plate 18. Although a lot of soot adhering to
the undersurface of the plate 18 may cause disadvantages such as
clogging of the two-fluid spray nozzle 38 due to the soot and
abnormal heating of the two-fluid sprayer 12 due to the soot
absorbing radiation heat from flame, by preventing soot from
sticking to the undersurface of the plate 18 as described above,
such disadvantages can be prevented from occurring.
[0183] Moreover, according to the two-fluid spray burner 11 of
Embodiment 1, the two-fluid spray burner 11 is configured so that
the first cylinder 16 extending downward from the undersurface of
the plate 18 for delaying supply of the combustion air is provided,
and the cylindrical combustion air passage 53 communicating with
the combustion air hole 52 is formed between the first cylinder 16
and the burner outer cylinder 48. The combustion air 50 passing
through the combustion air hole 52 is thus allowed to flow down the
combustion air passage 53 and then flow into the combustion space
13 from the lower end of the combustion air passage 53. It is
therefore possible to delay supply of a part of the combustion air
50 to the liquid fuel 24 sprayed from the two-fluid spray nozzle
38. In other words, the position where a part of the combustion air
50 is supplied to the liquid fuel 24 can be set downward away from
the plate 18. Accordingly, the position of flame is set downward
away from the plate 18, thus preventing soot from sticking to the
undersurface of the plate 18.
[0184] It is possible to obtain the operational effect of setting
the position where the part of the combustion air 50 is supplied to
the liquid fuel 24 downward away from the plate 18 by provision of
only the plate 18 as described above. However, as described in
Embodiment 1, by providing the first cylinder 16 for delaying
supply of the combustion air, the position where a part of the
combustion air 50 is supplied to the liquid fuel 24 can be more
surely set downward away from the plate 18.
[0185] Moreover, when the plate 18 cannot be made large so much
because of limitation on size of the two-fluid spray burner 11 and
the like, and the distance between the two-fluid spray nozzle 38
and combustion air hole 52 cannot be made long enough, the part of
the combustion air 50 supplied to the liquid fuel 24 becomes
excessive, and the flame may be excessively cooled. On the
contrary, by providing the first cylinder 16 for delaying supply of
combustion air as shown in Embodiment 1, not only the position
where the part of the combustion air 50 is supplied to the liquid
fuel 24 can be set downward away from the plate 18, but also the
amount of the part of the combustion air 50 supplied to the liquid
fuel 24 can be reduced to a proper amount. Accordingly, in such a
view, provision of the first cylinder 16 like Embodiment 1 is
effective. By providing the first cylinder 16, the plate 18 can be
reduced in size, and the two-fluid spray burner 11 can be
miniaturized.
[0186] Moreover, according to the two-fluid spray burner 11 of
Embodiment 1, the second cylinder 17 extending from the
undersurface of the plate 18 for preventing stagnation is provided
within the first cylinder 16 for delaying supply of combustion air.
Accordingly, stagnation (convection) of the liquid fuel 24 can be
prevented from occurring near the undersurface of the plate 18 by
the second cylinder 17 for preventing stagnation. It is therefore
possible to prevent the liquid fuel 24 stagnating near the
undersurface of the plate 18 from catching fire and soot from
sticking to the undersurface of the plate 18.
[0187] Moreover, according to the two-fluid spray burner 11 of
Embodiment 1, by surrounding flame with the burner outer cylinder
48, flame (the sprayed liquid fuel 24) and the combustion air 50
can be well mixed in the combustion space 13, thus improving the
combustion characteristics.
Embodiment 2
[0188] FIG. 6(a) is a longitudinal sectional view showing a
structure of lower part of a two-fluid sprayer in a two-fluid spray
burner according to Embodiment 2 of present invention, and FIG.
6(b) is a top view showing a two-fluid spray nozzle provided for
the two-fluid sprayer (a view in a direction of arrows E of FIG.
6(a)).
[0189] As shown in FIGS. 6(a) and 6(b), in a two-fluid spray nozzle
38 of a two-fluid sprayer 12 in Embodiment 2, grooves (slits) 61
are formed at four places in the circumference of the atomizing air
introduction portion 37. These grooves 61 are collision type. The
grooves 61 are individually extended in radial directions of the
two-fluid converging space portion 43 having a circular top view
and are formed at positions rotationally symmetric
(circumferentially at equal intervals) around the central axis of
the two-fluid converging space portion 43 (the central axis of the
spray hole 44 in the example of the drawing).
[0190] In the two-fluid sprayer 21, after flowing down the
atomizing air passage 28, the atomizing air 46 flows through the
grooves 61 of the atomizing air introduction portion 37 in the
two-fluid spray nozzle 38 to increase in flow speed and is
introduced into the two-fluid converging space portion 43. The
atomizing air 46 collides and converges (is mixed) with the liquid
fuel 24 discharged from the liquid fuel discharge hole 22 of the
liquid fuel tank 19 at the two-fluid converging space portion 43.
The liquid fuel 24 and atomizing air 46 are thus well mixed, and
the liquid fuel 24 is atomized with the atomizing air 46 and then
sprayed from the spray hole 44 of the two-fluid spray nozzle 38
together with the atomizing air 46 into the combustion space
13.
[0191] The configuration of the other parts of the two-fluid
sprayer 12 of FIG. 6 is the same as that of the two-fluid sprayer
12 of Embodiment 1 (FIG. 4) described above. The configuration of
the two-fluid spray burner 11 of Embodiment 2 other than the
two-fluid sprayer is the same as that of the two-fluid spray burner
11 of Embodiment 1 (FIGS. 1 to 3).
[0192] According to the two-fluid spray burner 11 of Embodiment 2,
the following operational effects can be obtained, and in addition,
the same operational effects as those of the aforementioned
Embodiment 1 can be obtained.
[0193] Specifically, according to the two-fluid spray burner 11 of
Embodiment 2, by forming the grooves 61 of the atomizing gas
introduction portion 37 along the radial directions of the
two-fluid converging space portion 43 in the top view, the
atomizing air 46 collides with the liquid fuel 24 at the two-fluid
converging space portion 43 to be mixed with the liquid fuel 24.
Accordingly, the liquid fuel 24 and atomizing air 46 are more
surely mixed. The liquid fuel 24 sprayed from the spray hole 44 of
the two-fluid spray nozzle 38 can be atomized more surely, thus
further improving the combustion characteristics of the liquid fuel
24.
[0194] Furthermore, the plurality of grooves 61 of the atomizing
gas introduction portion 37 are formed at positions rotationally
symmetric around the central axis of the two-fluid converging space
portion 43. Accordingly, the distribution of the liquid fuel 24
sprayed from the spray hole 44 of the two-fluid spray nozzle 38 can
be uniformed in the circumferential direction, thus improving the
combustion characteristics of the liquid fuel 24.
Embodiment 3
[0195] FIG. 7 (a) is a longitudinal sectional view showing a
structure of lower part of a two-fluid sprayer in a two-fluid spray
burner according to Embodiment 3 of present invention, and FIG.
7(b) is a top view showing a two-fluid spray nozzle provided for
the two-fluid sprayer (a view in a direction of an arrow F of FIG.
7(a)).
[0196] As shown in FIG. 7, in the two-fluid sprayer 12 in
Embodiment 3, the inner surface (top surface) 21a of the bottom
portion 21 of the liquid fuel tank 19 is a tapered (reverse
conical) surface, and the fine liquid fuel discharge hole 22 is
formed at the center (at the vertex position of the reverse conical
tapered surface). In the outer surface (undersurface) 21b of the
bottom portion 21 of the liquid fuel tank 19, an outside portion
21b-1 composed of a tapered (reverse truncated conical) surface,
and an inside portion 21b-2 is composed of a circular horizontal
surface.
[0197] On the other hand, the atomizing air introduction portion 37
of the two-fluid spray nozzle 38 is formed in a ring-shape, and an
inner peripheral surface 37b thereof is composed of a tapered
(reverse truncated cone-shaped) surface. The liquid fuel tank 19 is
installed on the atomizing air introduction portion 37 with the
outside portion 21b-1 (tapered surface portion) of the undersurface
21b of the bottom portion 21 being abutted and fitted into the
inner peripheral surface 37b (tapered surface portion) of the
atomizing air introduction portion 37. In this case, the liquid
fuel tank 19 is pressed downward by the coil spring 36 (see FIG.
4), and the outside portion 21b-1 (tapered surface portion) of the
undersurface 21b of the bottom portion 21 of the liquid fuel tank
19 is therefore pressed against the inner peripheral surface 37b
(tapered surface portion) of the atomizing air introduction portion
37 for a tight close contact, thus preventing gap between these
contact surfaces 21b-1 and 37b.
[0198] The nozzle body 39 of the two-fluid spray nozzle 38 includes
a reverse conical space (recess) 42 formed in the central part, and
the fine spray hole 44 is formed at the center (at the vertex
position of the reverse conical space 42). The space 41 of the
atomizing air introduction portion 37 and the space 42 of the
nozzle body 39 are continuous to each other and constitute the
two-fluid converging space portion 43. In other words, the
two-fluid converging space portion 43 has a circular plan view (top
view) and has a tapered structure with the diameter thereof
gradually reduced towards the spray hole 44. In the atomizing air
introduction portion 37, the grooves (slits) 40 are formed at two
places in the circumference thereof. These grooves 40 are swirling
type like the grooves 40 of FIG. 5 and are extended in tangent
directions of the circumference of the two-fluid converging space
portion 43 in a top view. Moreover, the grooves 40 are formed at
positions rotationally symmetric around a central axis of the
two-fluid converging space portion 43 (circumferentially at equal
intervals). The grooves formed at the atomizing air introduction
portion 37 are not limited to the swirling type but may be
collision type like that of FIG. 6.
[0199] The configuration of the other parts of the two-fluid
sprayer 12 of FIG. 7 is the same as that of the two-fluid sprayer
12 of Embodiment 1 (FIG. 4) described above. The configuration of
the two-fluid spray burner 11 of Embodiment 3 other than the
two-fluid sprayer is the same as that of the two-fluid spray burner
11 of Embodiment 1 (FIGS. 1 to 3).
[0200] According to the two-fluid spray burner 11 of Embodiment 3,
the following operational effects can be obtained, and in addition,
the same operational effects as those of the aforementioned
Embodiments 1 and 2 can be obtained.
[0201] Specifically, according to the two-fluid spray burner of
Embodiment 3, the liquid fuel tank 19 is installed on the atomizing
gas introduction portion 37 with the tapered surface portion (the
outside portion 21b-1 of the undersurface 21b of the bottom portion
21) of the liquid fuel tank 19 being abutted and fitted to the
tapered surface portion (inner peripheral surface 37b) of the
atomizing gas introduction portion 37. It is therefore easy to
align the central axes of the liquid fuel tank 19 and two-fluid
spray nozzle 38. Accordingly, the liquid fuel tank 19 is installed
at the center. The width of the atomizing air passage 28 can be
therefore made uniform in circumferential direction, so that the
flow of the atomizing air 46 in the atomizing air passage 28 can be
made uniform in the circumferential direction. This makes it
possible to hold the symmetric properties of the liquid fuel 24 (or
symmetric properties of the flame) sprayed from the spray hole 44
of the two-fluid spray nozzle 38.
[0202] Moreover, according to the two-fluid spray burner 11 of
Embodiment 3, by pressing the liquid fuel tank 19 downward by the
coil spring 36 (see FIG. 4), the bottom portion 21 of the liquid
fuel tank 19 is pressed against the atomizing air introduction
portion 37 of the two-fluid spray nozzle 38 to bring the tapered
surface portion (outside portion 21b-1) of the bottom portion 21 of
the fuel tank 19 and the tapered surface portion (inner peripheral
surface 37b) of the atomizing air introduction portion 37 into firm
contact, thus preventing gap between these contact surfaces 21b-1
and 37b. It is therefore possible to prevent the atomizing air 46
from flowing into portions other than the grooves 40, thus allowing
the effect of the wide spray by the grooves 40 to be sufficiently
exerted.
Embodiment 4
[0203] FIG. 8(a) is a longitudinal sectional view showing a
structure of lower part of a two-fluid sprayer in a two-fluid spray
burner according to Embodiment 4 of the present invention (a
longitudinal sectional view taken along a line G-G of FIG. 8(b));
FIG. 8(b) is a bottom view showing a liquid fuel tank provided for
the two-fluid sprayer (a view in a direction of an arrow H of FIG.
8(a)); FIG. 8(c) is a view in a direction of an arrow I of FIG.
8(b); and FIG. 8(d) is a transverse sectional view taken along a
line J-J of FIG. 8(a).
[0204] As shown in FIG. 8, in the two-fluid sprayer 12 of
Embodiment 4, the inner surface (top surface) 21a of the bottom
portion 21 of the liquid fuel tank 19 is composed of a tapered
(reverse conical) surface, and the fine liquid fuel discharge hole
22 is formed at the center (at the vertex position of the reverse
conical tapered surface). Moreover, in the outer surface
(undersurface) 21b of the bottom portion 21 of the liquid fuel tank
19, the outside portion 21b-1 is composed of a tapered (reverse
truncated cone-shaped) surface, and an inside portion 21b-2 is
composed of a circular horizontal surface.
[0205] On the other hand, the two-fluid spray nozzle 38 does not
include an atomizing air introduction portion (see FIG. 7) and is
integrally formed with the sprayer outer cylinder 27 at the lower
end of the sprayer outer cylinder 27 (a separate body may be fixed
by welding or the like). The two-fluid spray nozzle 38 has the
inner surface (top surface) 38a which is composed of a tapered
(reverse conical) surface. The liquid fuel tank 19 is installed on
the two-fluid spray nozzle 38 with the outside portion 21b-1
(tapered surface portion) of the undersurface 21b of the bottom
portion 21 being abutted and fitted to the inner surface 38a
(tapered surface portion) of the two-fluid spray nozzle 38. In this
case, the liquid fuel tank 19 is pressed downward by the coil
spring 36 (see FIG. 4), so that the outside portion 21b-1 (tapered
surface portion) of the undersurface 21b of the bottom portion 21
of the liquid fuel tank 19 is pressed against the inner surface 38a
(tapered surface portion) of the two-fluid spray nozzle 38 to be
brought into firm contact, thus preventing gap between these
contact surfaces 21b-1 and 38b.
[0206] A reverse conical space formed by the inner surface 38a of
the tapered structure in the central part of the two-fluid spray
nozzle 38 serves as the two-fluid converging space portion 43. The
fine spray hole 44 is formed at the center (the vertex position of
a reverse conical space 43) of the two-fluid converging space
portion 43 and communicates with the two-fluid converging space
portion 43. Specifically, the two-fluid converging space portion 43
has a circular plan view (top view) and has a tapered structure
with the diameter thereof gradually reduced towards the spray hole
44.
[0207] In the undersurface 21b side of the bottom portion 21 of the
liquid fuel tank 19, grooves (slits) 71 are formed at two places in
the circumference thereof. These grooves 71 are swirling type and
are extended in tangent directions of the circumference of the
two-fluid converging space portion 43 in a top view. Moreover, the
grooves 71 are formed at positions rotationally symmetric around a
central axis of the two-fluid converging space portion 43
(circumferentially at equal intervals).
[0208] Accordingly, after flowing down the atomizing air passage
28, the atomizing air 46 flows through the grooves 71 of the bottom
portion 21 of the liquid fuel tank 19 to increase in flow rate and
is then introduced to the two-fluid converging space portion 43.
The atomizing air 46 becomes swirling flow in the two-fluid
converging space portion 43 and converges (is mixed) with the
liquid fuel 24 discharged from the liquid fuel discharge hole 22 of
the liquid fuel tank 19. The liquid fuel 24 and atomizing air 46
are thus well mixed, and the liquid fuel 24 is atomized with the
atomizing air 46 and sprayed from the spray hole 44 of the
two-fluid spray nozzle 38 into a combustion space 13.
[0209] The configuration of the other parts of the two-fluid
sprayer 12 of FIG. 8 is the same as that of the two-fluid sprayer
12 of Embodiment 1 (FIG. 4) described above. The configuration of
the two-fluid spray burner 11 of Embodiment 4 other than the
two-fluid sprayer is the same as that of the two-fluid spray burner
11 of Embodiment 1 (FIGS. 1 to 3).
[0210] According to the two-fluid spray burner 11 of Embodiment 4,
the following operational effects can be obtained, and in addition,
the same operational effects as those of the aforementioned
Embodiment 1 can be obtained.
[0211] According to the two-fluid spray burner 11 of Embodiment 4,
the two-fluid spray burner is configured so that the liquid fuel 24
which is discharged from the liquid fuel discharge hole 44 and
flows into the two-fluid converging space portion 43 converges at
the two-fluid converging space portion 43 with the atomizing air 46
flowing down the atomizing air passage 28 and then flowing through
the grooves 71 at the bottom portion 21 of the liquid fuel tank 19
to be introduced into the two-fluid converging space portion 43 and
then is sprayed from the spray hole 44 together with the atomizing
air 46. Accordingly, the liquid fuel 24 is well mixed with the
atomizing air 46 whose the flow rate is increased through the
grooves 71 (with the horizontal speed component increased) at the
two-fluid converging space portion 43 and then sprayed from the
spray hole 44. Accordingly, compared to the case of not providing
the two-fluid converging space portion 43 and grooves 71, the
spread angle of the sprayed liquid fuel 24 is larger, and the
liquid fuel 24 is surely atomized, thus improving the combustion
characteristics of the liquid fuel 24.
[0212] Furthermore, the liquid fuel tank 19 is installed on the
two-fluid spray nozzle 38 with the tapered surface portion (the
outside portion 21b-1 of the undersurface 21b of the bottom portion
21) of the liquid fuel tank 19 abutted and fitted to the tapered
surface portion (inner surface 38a) of the two-fluid spray nozzle
38. Thus, it is easy to align the central axes of the liquid fuel
tank 19 and two-fluid spray nozzle 38. Accordingly, the liquid fuel
tank 19 is installed at the center. The width of the atomizing air
passage 28 can be therefore made uniform in circumferential
direction, so that the flow of the atomizing air 46 in the
atomizing air passage 28 can be made uniform in the circumferential
direction. It is therefore possible to secure the symmetric
properties of the liquid fuel 24 (or symmetric properties of flame)
sprayed from the spray hole 44 of the two-fluid spray nozzle
38.
[0213] Moreover, the grooves 71 of the bottom portion 21 of the
liquid fuel tank 19 are formed along the tangent directions of the
circumference of the two-fluid converging space portion 43 in a top
view. Accordingly, the atomizing air 46 is swirled and mixed with
the liquid fuel 24 at the two-fluid converging space portion 43.
The liquid fuel 24 and atomizing air 46 are thus mixed more surely.
The liquid fuel 24 sprayed from the spray hole 44 of the two-fluid
spray nozzle 38 can be therefore surely atomized, thus improving
the combustion characteristics of the liquid fuel 24.
[0214] Moreover, the plurality of grooves 71 of the bottom portion
21 of the liquid fuel tank 19 are formed at positions rotationally
symmetric around the central axis of the two-fluid converging space
portion 43. Accordingly, the liquid fuel 24 sprayed from the spray
hole 44 of the two-fluid spray nozzle 38 is uniformly distributed
in the circumferential direction, thus improving the combustion
characteristics of the liquid fuel 24.
[0215] According to the two-fluid spray burner 11 of Embodiment 4,
by pressing the liquid fuel tank 19 downward by the coil spring 36
(see FIG. 4), the bottom portion 21 of the liquid fuel tank 19 is
pressed against the two-fluid spray nozzle 38, so that the tapered
surface portion (outside portion 21b-1) of the bottom portion 21 of
the fuel tank 19 and the tapered surface portion (inner surface
38a) of the two-fluid spray nozzle 38 are brought into firm
contact, thus preventing gap between these contact surfaces 21b-1
and 38a. It is therefore possible to prevent the atomizing air 46
from flowing into portions other than the grooves 71, thus allowing
the effect of the wide spray by the grooves 71 to be sufficiently
exerted.
Embodiment 5
[0216] FIG. 9(a) is a longitudinal sectional view showing a
structure of lower part of a two-fluid sprayer in a two-fluid spray
burner according to Embodiment 5 (a longitudinal sectional view
taken along a line K-K of FIG. 9(b)); FIG. 9(b) is a bottom view
showing a liquid fuel tank provided for the two-fluid sprayer (a
view in a direction of an arrow L of FIG. 9(a)); and FIG. 9 (c) is
a transverse sectional view taken along a line M-M of FIG.
9(a).
[0217] As shown in FIG. 9, in the two-fluid sprayer 12 of
Embodiment 5, the inner surface (top surface) 21a of the bottom
portion 21 of the liquid fuel tank 19 is composed of a tapered
(reverse conical) surface, and the fine liquid fuel discharge hole
22 is formed at the center (at the vertex position of the reverse
conical tapered surface). Moreover, in the outer surface
(undersurface) 21b of the bottom portion 21 of the liquid fuel tank
19, the outside portion 21b-1 is composed of a tapered (reverse
truncated cone-shaped) surface, and an inside portion 21b-2 is
composed of a circular horizontal surface.
[0218] On the other hand, the two-fluid spray nozzle 38 does not
include an atomizing air introduction portion (see FIG. 7) and is
integrally formed with the sprayer outer cylinder 27 at the lower
end of the sprayer outer cylinder 27 (a separate body may be fixed
by welding or the like). The two-fluid spray nozzle 38 has the
inner surface (top surface) 38a which is composed of a tapered
(reverse conical) surface. The liquid fuel tank 19 is installed on
the two-fluid spray nozzle 38 with the outside portion 21b-1
(tapered surface portion) of the undersurface 21b of the bottom
portion 21 abutted and fitted to the inner surface 38a (tapered
surface portion) of the two-fluid spray nozzle 38. In this case,
the liquid fuel tank 19 is pressed downward by the coil spring 36
(see FIG. 4), so that the outside portion 21b-1 (tapered surface
portion) of the undersurface 21b of the bottom portion 21 of the
liquid fuel tank 19 is pressed against the inner surface 38a
(tapered surface portion) of the two-fluid spray nozzle 38 and
brought into firm contact, thus preventing gap between these
contact surfaces 21b-1 and 38b.
[0219] A reverse conical space formed by the inner surface 38a with
the tapered structure in the central part of the two-fluid spray
nozzle 38 serves as the two-fluid converging space portion 43. The
fine spray hole 44 is formed at the center (the vertex position of
the reverse conical space 43) of the two-fluid converging space
portion 43 and communicates with the two-fluid converging space
portion 43. Specifically, the two-fluid converging space portion 43
has a circular plan view (top view) and has a tapered structure
with the diameter thereof gradually reduced towards the spray hole
44.
[0220] In the undersurface 21b side of the bottom portion 21 of the
liquid fuel tank 19, grooves (slits) 81 are formed at four places
in the circumference thereof. These grooves 81 are the collision
type and are extended in radial directions of the two-fluid
converging space portion 43 in a top view and are formed at
positions rotationally symmetric around the central axis of the
two-fluid converging space portion 43 (circumferentially at equal
intervals).
[0221] After flowing down the atomizing air passage 28, the
atomizing air 46 flows through the grooves 81 at the bottom portion
21 of the liquid fuel tank 19 to increase in flow speed and then
introduced to the two-fluid converging space portion 43. The
atomizing air 46 collides and converges (is mixed) with the liquid
fuel 24 discharged from the liquid fuel discharge hole 22 of the
liquid fuel tank 19 at the two-fluid converging space portion 43.
The liquid fuel 24 and atomizing air 46 are thus well mixed, and
the liquid fuel 24 is atomized with the atomizing air 46 and then
sprayed from the spray hole 44 of the two-fluid spray nozzle 38
together with the atomizing air 46 into the combustion space
13.
[0222] The configuration of the other parts of the two-fluid
sprayer 12 of FIG. 9 is the same as that of the two-fluid sprayer
12 of Embodiment 1 (FIG. 4) described above. The configuration of
the two-fluid spray burner 11 of Embodiment 5 other than the
two-fluid sprayer is the same as that of the two-fluid spray burner
11 of Embodiment 1 (FIGS. 1 to 3).
[0223] According to the two-fluid spray burner 11 of Embodiment 5,
the same operational effects as those of the aforementioned
Embodiment 4 can be obtained, and in addition, the same operational
effects as those of the aforementioned Embodiment 1 can be
obtained.
[0224] According to the two-fluid spray burner 11 of Embodiment 5,
the two-fluid spray burner is configured so that the liquid fuel 24
which is discharged from the liquid fuel discharge hole 44 and
flows into the two-fluid converging space portion 43 converges at
the two-fluid converging space portion 43 with the atomizing air 46
which flows down the atomizing air passage 28 and then flows
through the grooves 81 at the bottom portion 21 of the liquid fuel
tank 19 and then is introduced into the two-fluid converging space
portion 43 to be sprayed from the spray hole 44 together with the
atomizing air 46. The liquid fuel 24 is therefore well mixed with
the atomizing air 46 with the flow rate increased through the
grooves 81 (with the horizontal speed component increased) at the
two-fluid converging space portion 43 and then sprayed from the
spray hole 44. Compared to the case of not providing the two-fluid
converging space portion 43 and grooves 81, the spread angle of the
sprayed liquid fuel 24 is larger, and the liquid fuel 24 is surely
atomized, thus improving the combustion characteristics of the
liquid fuel 24.
[0225] Furthermore, the liquid fuel tank 19 is installed on the
two-fluid spray nozzle 38 with the tapered surface portion (the
outside portion 21b-1 of the undersurface 21b of the bottom portion
21) of the liquid fuel tank 19 abutted and fitted in the tapered
surface portion (inner surface 38a) of the two-fluid spray nozzle
38, and it is therefore easy to align the central axes of the
liquid fuel tank 19 and two-fluid spray nozzle 38. Accordingly, the
liquid fuel tank 19 is installed at the center. The width of the
atomizing air passage 28 can be therefore made uniform in
circumferential direction, so that the flow of the atomizing air 46
in the atomizing air passage 28 can be made uniform in the
circumferential direction. It is therefore possible to secure the
symmetric properties of the liquid fuel 24 (or symmetric properties
of flame) sprayed from the spray hole 44 of the two-fluid spray
nozzle 38.
[0226] Moreover, the grooves 81 of the bottom portion 21 of the
liquid fuel tank 19 are formed along tangent directions of the
circumference of the two-fluid converging space portion 43 in a top
view. Accordingly, the atomizing air 46 is swirled and mixed with
the liquid fuel 24 at the two-fluid converging space portion 43,
and the liquid fuel 24 and atomizing air 46 are thus mixed more
surely. The liquid fuel 24 sprayed from the spray hole 44 of the
two-fluid spray nozzle 38 can be therefore surely atomized, thus
improving the combustion characteristics of the liquid fuel 24.
[0227] Moreover, the plurality of grooves 81 of the bottom portion
21 of the liquid fuel tank 19 are formed at positions rotationally
symmetric around the central axis of the two-fluid converging space
portion 43. Accordingly, the liquid fuel 24 sprayed from the spray
hole 44 of the two-fluid spray nozzle 38 can be uniformly
distributed in the circumferential direction, thus improving the
combustion characteristics of the liquid fuel 24.
[0228] In the two-fluid spray burner 11 of Embodiment 4, by
pressing the liquid fuel tank 19 downward by the coil spring 36
(see FIG. 4), the bottom portion 21 of the liquid fuel tank 19 is
pressed against the two-fluid spray nozzle 38 to bring the tapered
surface portion (outside portion 21b-1) of the bottom portion 21 of
the fuel tank 19 and the tapered surface portion (inner surface
38a) of the two-fluid spray nozzle 38 into firm contact, thus
preventing gap between these contact surfaces 21b-1 and 38a. It is
therefore possible to prevent the atomizing air 46 from flowing
into portions other than the grooves 81, thus allowing the effect
of the wide spray by the grooves 81 to be sufficiently exerted.
Embodiment 6
[0229] FIG. 10(a) is a longitudinal sectional view showing a
structure of lower part of a two-fluid sprayer in a two-fluid spray
burner according to Embodiment 6; and FIG. 10(b) is a transverse
sectional view taken along a line N-N of FIG. 10(a).
[0230] As shown in FIG. 10, in the two-fluid sprayer 12 of
Embodiment 6, the inner surface (top surface) 21a of the bottom
portion 21 of the liquid fuel tank 19 is composed of a tapered
(reverse conical) surface, and the fine liquid fuel discharge hole
22 is formed at the center (at the vertex position of the reverse
conical tapered surface). The outer surface (undersurface) 21b of
the bottom portion 21 of the liquid fuel tank 19 is composed of a
tapered (reverse truncated cone-shaped) surface. On the other hand,
the two-fluid spray nozzle 38 does not include an atomizing air
introduction portion (see FIG. 7) and is integrally formed with the
sprayer outer cylinder 27 at the lower end of the sprayer outer
cylinder 27 (a separate body may be fixed by welding or the like).
In the two-fluid spray nozzle 38, the inner surface (top surface)
38a is composed of a tapered (reverse conical) surface.
[0231] In the lower end portion of the outer peripheral surface 20b
of the side portion 20 of the liquid fuel tank 19, a plurality of
supporting portions 91 are provided in a protruding manner (four in
the example of the drawing). These supporting portions 91 are
provided at equal intervals in the circumferential direction of the
side portion 20. Outside portions 91a-1 of undersurfaces 91a are
individually composed of tapered surfaces which are sloped inward
along the inner surface 38a of the two-fluid spray nozzle 38. The
liquid fuel tank 19 is therefore supported with the outside
portions 91a-1 of the undersurfaces 91a of the supporting portions
91 abutted and fitted to the inner surface 38a of the two-fluid
spray nozzle 38. Accordingly, the tapered (reverse truncated
cone-shaped) gaps are secured between the outer surface 21a of the
bottom portion 21 of the liquid fuel tank 19 and the inner surface
38a of the two-fluid spray nozzle 38 and serve as atomizing air
passages 92. In other words, the first atomizing air passage 28
outside and the two-fluid converging space portion 43 inside
communicate with each other through the second atomizing air
passages 92.
[0232] The two-fluid converging space portion 43 is a reverse
conical space formed in the central part of the two-fluid spray
nozzle 38 by the inner surface 38a of a tapered structure. The fine
spray hole 44 is formed at the center of the two-fluid converging
space portion 43 (the vertex position of the reverse conical space
43) and communicates with the two-fluid converging space portion
43. Specifically, the two-fluid converging space portion 43 is
located under the liquid fuel discharge hole 22 and has a tapered
structure including a circular plan view (top view) with the
diameter thereof gradually reduced towards the spray hole 44.
[0233] After flowing down the atomizing air passage 28, the
atomizing air 46 passes through atomizing air passage portions
between the supporting portions 91 and flows through the atomizing
air passages 92 to be introduced to the two-fluid converging space
portion 43. The atomizing air 46 collides and converges (is mixed)
with the liquid fuel 24 discharged from the liquid fuel discharge
hole 22 of the liquid fuel tank 19 at the two-fluid converging
space portion 43. The liquid fuel 24 is atomized with the atomizing
air 46 and then sprayed from the spray hole 44 of the two-fluid
spray nozzle 38 together with the atomizing air 46 into the
combustion space 13.
[0234] The configuration of the other parts of the two-fluid
sprayer 12 of FIG. 10 is the same as that of the two-fluid sprayer
12 of Embodiment 1 (FIG. 4) described above. The constitution of
the two-fluid spray burner 11 of Embodiment 6 other than the
two-fluid sprayer is the same as that of the two-fluid spray burner
11 of Embodiment 1 (FIGS. 1 to 3).
[0235] According to the two-fluid spray burner 11 of Embodiment 6,
the following operational effects can be obtained, and in addition,
the same operational effects as those of the aforementioned
Embodiment 1 can be obtained.
[0236] Specifically, according to the two-fluid spray burner 11 of
Embodiment 6, the liquid fuel 24 which is discharged from the
liquid fuel discharge hole 22 and flows into the two-fluid
converging space portion 43 converges at the two-fluid converging
space portion 43 with the atomizing air 46 which flows down the
first atomizing gas passage 28, through the atomizing air passage
portions 93 between the supporting portions 91, and through the
second atomizing air passage 92 to be introduced into the two-fluid
converging space portion 43 and is then sprayed from the spray hole
44 with the atomizing air 46. Accordingly, the liquid fuel 24 is
mixed with the atomizing air 46 at the two-fluid converging space
portion 43 and then sprayed from the spray hole 44 of the two-fluid
spray nozzle 38. Accordingly, compared to the case of not providing
the two-fluid converging space portion 43, the spread angle of the
sprayed liquid fuel 24 is larger, and the liquid fuel 24 is surely
atomized, thus improving the combustion characteristics of the
liquid fuel 24.
Embodiment 7
[0237] FIG. 11 is a longitudinal sectional view showing a structure
of a two-fluid spray burner according to Embodiment 7 of the
present invention; and FIG. 12 is a transverse sectional view taken
along a line 0-0 of FIG. 11.
[0238] As shown in FIGS. 11 and 12, in the two-fluid spray burner
11 of Embodiment 7, the plate 18 is a porous plate. Specifically,
in the ring-shaped plate 18, a plurality of combustion air holes
101 are formed. All of these combustion air holes 101 are provided
inside of the combustion air hole 52 (first cylinder 16).
Accordingly, after flowing down the combustion air passage 15, most
of the combustion air 50 passes through the combustion air hole 52
on the outer periphery of the plate 19, flows through the
combustion air passage 53 located outside of the first cylinder 16
and into the combustion space 13. Meanwhile, a part of the
combustion air 50 flows through the combustion air holes 101
located inside of the first cylinder 16 and into the combustion
space 13.
[0239] The configuration of the other part of the two-fluid spray
burner 11 of FIGS. 11 and 12 is the same as that of the two-fluid
spray burner 11 of Embodiment 1 (FIGS. 1 to 3).
[0240] According to the two-fluid spray burner 11 of Embodiment 7,
the following operational effects can be obtained, and in addition,
the same operational effects as those of the aforementioned
Embodiment 1 can be obtained.
[0241] Specifically, according to the two-fluid spray burner 11 of
Embodiment 7, by forming the plurality of additional combustion air
holes 101 in the plate 18 position inside of the combustion air
hole 52, a part of the combustion air 50 flows through these
combustion air holes 101. Such a flow of the combustion air 50 can
suppress stagnation of the combustion air occurring near the
undersurface of the plate 18, thus reducing adherence of soot to
the plate 18. Moreover, the cool combustion air flows near the
two-fluid spray nozzle 38 through the other combustion air holes
101. It is therefore possible to obtain a cooling effect on the
two-fluid spray nozzle 38, with the combustion air, which tends to
be excessively heated by radiation heat from flame.
Embodiment 8
[0242] FIG. 14(a) is a longitudinal sectional view showing a
structure of a two-fluid spray burner according to Embodiment 8 of
the present invention, and FIG. 14(b) is a transverse sectional
view taken along a line P-P of FIG. 14(a). FIG. 15 is a graph
showing a relation between a ratio (L/D) and an optimal setting
position of the throttle plate. Here, (L) is a distance between the
spray hole of two-fluid sprayer and the throttle plate. (D) is a
diameter of the combustion space portion.
[0243] As shown in FIGS. 14(a) and 14(b), the two-fluid spray
burner 11 of Embodiment 8 is provided with a throttle plate 121 in
the combustion space portion 13 within the burner outer cylinder
48. The throttle plate 121 has a ring shape with a circular passage
hole (throttle hole) 122 opened at central part thereof. The
throttle plate 121 is horizontally placed at the lower end portion
of the extended burner outer cylinder 48 under the plate 18, first
cylinder 16, and the like, and is fixed to the inner surface of the
burner outer cylinder 48 by fixing means such as welding. As shown
in FIG. 14(b), the passage hole 122 of the throttle plate 121 is
located in the central part of the combustion space portion 13 in a
top view.
[0244] Accordingly, as indicated by arrows in FIG. 14(a), the
combustion air 50 flowing down the combustion space portion 13 is
introduced by the throttle plate 121 to the central part of the
combustion space portion 13 to pass through the passage hole 122 of
the throttle plate 121. The throttle plate 121 is not necessarily
limited to a horizontal plate indicated by a solid line in FIG.
14(a) and may be a tilted plate (reverse truncated cone-shaped
plate) virtually indicated by a dotted-dashed line in FIG.
14(a).
[0245] The configuration of the other parts of the two-fluid spray
burner 11 of FIG. 14 is the same as that of the two-fluid spray
burner 11 of Embodiment 1 (FIGS. 1 to 3) described above.
[0246] According to the two-fluid spray burner 11 of Embodiment 8,
it is possible to obtain the same operational effects as those of
Embodiment 1 described above and also obtain the following
operational effects.
[0247] Specifically, according to the two-fluid spray burner 11 of
Embodiment 8, the throttle plate 121 with the passage hole 121
opened in the central part thereof is provided for the combustion
space portion 13 so that the combustion air 50 flowing down the
combustion space portion 13 is introduced to the central part of
the combustion space portion 13 and passes through the passage hole
122 of the throttle plate 121. Accordingly, mixture of the
combustion air 50 and unburned gas (sprayed liquid fuel heated and
vaporized but not burned yet) is promoted, and the combustion of
the unburned gas is therefore promoted. It is therefore possible to
accomplish complete combustion of the fuel and shorten the flame
123.
[0248] To be specific, the combustion air 50 flowing the combustion
air passage 53 and then flowing into the combustion space portion
13 from the lower end of the combustion air passage 53 (in the case
of not providing the first cylinder 16, the combustion air 50
flowing through the combustion air passage hole 52 and flowing into
the combustion space portion 13) flows down the combustion space
portion 13 and spreads towards the center part of the combustion
space portion 13 and is mixed with the unburned gas for combustion
of the unburned gas. However, not all of the combustion air 50
reaches the central part of the combustion space portion 13, and a
part of the combustion air 50 is not mixed with the unburned gas
and further flows downward. In the case where the combustion space
portion 13 is not provided with the throttle plate 12, the
combustion air 50 and unburned gas are mixed late, and fuel tends
to remain unburned (unburned gas), thus lengthening the flame
123.
[0249] On the other hand, in the case where the combustion space
portion 13 is provided with the throttle plate 121 as described
above, the combustion air 50 flowing down is blocked by the
throttle plate 121 to be introduced to the passage hole 122 (or the
central part of the combustion space portion 13) in the central
part. Accordingly, the mixture of the combustion air 50 and
unburned gas is promoted, and combustion of unburned gas is
promoted. It is therefore easy to accomplish complete combustion of
the fuel, so that CO is reduced and the flame 123 is shortened.
[0250] In addition, according to the two-fluid spray burner 11 of
Embodiment 8, fluid such as the combustion air is once throttled by
the passage hole 122 of the throttle plate 121, thus equalizing the
distribution of the flow rate of the fluid is in the
circumferential direction. Accordingly, it is possible to heat a
furnace or the like with the combustion exhaust gas uniformly in
the circumferential direction.
[0251] It is desirable to set the range of L/D within 2 to 10 (in a
region I of FIG. 15). Here L is a distance between the spray hole
44 of the two-fluid sprayer 12 and the throttle plate 121, and D is
an inner diameter (diameter of the combustion space portion 13) of
the burner outer cylinder 48 as shown in FIG. 14. When L/D is
smaller than 2 (region II of FIG. 15), a comparatively large amount
of air is supplied at once to cool the flame. Accordingly, fuel is
less likely to be vaporized, and droplets are more likely to be
generated. On the other hand, when L/D is larger than 10 (a region
III of FIG. 15), air supply is late, and the proportion of air
mixed with the unburned gas with low temperature is increased.
Accordingly, the combustion of unburned gas (reaction with 02 in
air) is difficult to promote.
[0252] Where d is a diameter of the passage hole of the throttle
plate 121, it is desirable to set the range of d/D within 0.2 to
0.6, as shown in FIG. 14. When d/D is less than 0.2, pressure of
the combustion space portion 12 is greatly increased. When d/D is
more than 0.6, the effect on mixture of air and unburned gas is
reduced.
Embodiment 9
[0253] FIG. 16(a) is a longitudinal sectional view showing a
structure of a two-fluid spray burner according to Embodiment 9 of
the present invention; FIG. 16(b) is a transverse sectional view
taken along a line Q-Q of 16(a); and FIG. 16(c) is a transverse
sectional view corresponding to FIG. 16(b), showing another
structure example of swirling blades.
[0254] As shown in FIGS. 16(a) to 16(c), the two-fluid spray burner
11 of Embodiment 9 includes swirling blades 124 above the throttle
plate 121. The plurality of swirling blades 124 (six blades) are
provided around the passage hole 122 of the throttle plate 12 at
equal intervals in the circumferential direction of the passage
hole 122 and fixed to the upper surface of the throttle plate 121
and the inner surface of the burner outer cylinder 48 by fixing
means such as welding. Each of the swirling blades 124 is provided
along substantially tangent directions of the circular passage hole
122 in a top view. Accordingly, the flow of the combustion air 50
passing through the passage hole 122 of the throttle plate 121 is
formed into a swirling flow by the swirling blades 124 as indicated
by arrows in FIGS. 16(b) and 16(c).
[0255] The directions that the swirling blades 124 are extended in
the top view are not limited to the tangent directions of the
passage hole 122. Each swirling blade 124 just should have its side
surface inclined with respect to a radial direction of the passage
hole 122 in a plan view. The swirling blades 124 may be planer as
shown in FIG. 16(b) or may be curved as shown in FIG. 16(c).
[0256] The configuration of the other part of the two-fluid spray
burner 11 of FIG. 16 is the same as that of the two-fluid spray
burners 11 of Embodiments 1 and 8 (FIGS. 1 to 3, FIG. 14) described
above.
[0257] According to the two-fluid spray burner 11 of Embodiment 9,
it is possible to obtain the same operational effects as those of
the aforementioned Embodiments 1 and 8 and furthermore obtain the
following operational effects.
[0258] Specifically, according to the two-fluid spray burner 11 of
Embodiment 9, the swirling blades 124 are provided above the
throttle plate 121 to form the combustion air 50 passing through
the passage hole 122 of the throttle plate 121 into a swirling flow
by the swirling blades 124. Accordingly, the combustion air 55
passing through the passage hole 122 of the throttle plate 121
swirls and spreads horizontally as indicated by arrows of FIG.
16(a). Pressure of the central part in the flow of the combustion
air 50 is therefore reduced under the passage hole 122, thus
generating a circulating flow of the combustion air 50 flowing from
the outside into the central part as indicated by the arrows in
FIG. 16(a). Accordingly, the mixture of the combustion air 50 and
unburned gas is further promoted, and the combustion of the
unburned gas is further promoted. Fuel is therefore more likely to
be completely burned, and the flame 123 is further shortened.
Embodiment 10
[0259] FIG. 17(a) is a longitudinal sectional view showing a
structure of a two-fluid spray burner according to Embodiment 10 of
the present invention; and FIG. 17(b) is a transverse sectional
view taken along a line R-R of FIG. 17(a).
[0260] As shown in FIGS. 17(a) and 17(c), the two-fluid spray
burner 11 of Embodiment 10 includes a plurality of porous plates
(two pieces in the example of the drawing) in the combustion space
portion 13. The number of the porous plates 125 is not limited to a
plural number and may be one. The porous plates 125 are located
above the throttle plate 121, that is, between the plate 18 (the
first cylinder 16) and the throttle plate 121.
[0261] The porous plate 125 is a ring-shaped plate with a
comparatively large diameter passage hole 127 opened in the central
part and with a lot of comparatively small diameter holes 126
opened around the same. The porous plates 125 are horizontally
placed inside the combustion space portion 13 and fixed to the
inner surface of the burner outer cylinder 48 by fixing means such
as welding. As shown in FIG. 17(b), the passage hole 127 of the
porous plate 125 is located at the central part of the combustion
space portion 13 in a plan view.
[0262] Accordingly, a part of the combustion air 50 flowing down
the combustion space portion 13 is introduced to the passage holes
127 at the central part by the porous plates 125 (or the central
part of the combustion space portion 13) to pass through the
passages 127, while the other combustion air 50 flows through the
holes 126 downward. For example, at an upper one of the porous
plates 125, 20% of the combustion air 50 flowing down toward the
porous plates 125 is introduced to the central part while 80%
thereof passes through the holes 126 and further flows downward. At
a lower one of the porous plates 125, 40% of the combustion air 50
flowing down toward the porous plate 125 is introduced to the
central part while 60% thereof passes through the holes 126 and
further flows downward.
[0263] The configuration of the other part of the two-fluid spray
burner 11 of FIG. 17 is the same as those of the two-fluid spray
burners 11 of Embodiments 1, 8, and 9 described above (FIGS. 1 to
3, FIG. 14).
[0264] According to the two-fluid spray burner 11 of Embodiment 10,
it is possible to obtain the same operational effects as those of
the aforementioned Embodiments 1, 8, and 9 and further obtain the
following operational effects.
[0265] Specifically, according to the two-fluid spray burner 11 of
Embodiment 10, the porous plates 125 each having the passage hole
127 opened in the central part are provided above the throttle
plate 121 in the combustion space portion 13 so that a part of the
combustion air 50 flowing down the combustion space portion 13 is
introduced to the central part of the combustion space portion 13
by the porous plates 125 and passes through the passage holes 127
of the porous plates 125. Accordingly, the mixture of the
combustion air 50 and unburned gas is further promoted, and the
combustion of the unburned gas is further promoted. It is therefore
easy to accomplish complete combustion of the fuel, thus further
shortening the flame 123.
Embodiment 11
[0266] FIG. 18 is a system diagram schematically showing a fuel
cell power generation system according to Embodiment 11 of the
present invention. FIG. 18 shows an example of a case where the
two-fluid spray burner 11 of any one of the aforementioned
Embodiments 1 to 10 is used as a heat source for a reformer in the
fuel cell power generation system.
[0267] As shown in FIG. 18, a combustion furnace 112 is provided in
upper part of a reformer 111, and the two-fluid spray burner 11 of
any one of the aforementioned Embodiments 1 to 10 is inserted into
the combustion furnace 112 from above. The two-fluid spray burner
11 is connected to a liquid fuel supply system, an atomizing air
supply system, and a combustion air supply system which are not
shown. The details of the two-fluid spray burner 11 are described
above.
[0268] The reformer 111 is connected to an unillustrated raw
material supply system. The raw material supply system supplies, to
the reformer 111, water and reforming fuel which is raw material
for reforming such as methane gas or kerosene. In the reformer 111,
the reforming fuel is steam-reformed by using the large amount of
combustion exhaust gas produced by combustion at the two-fluid
spray burner 11, thus generating reforming gas (hydrogen rich gas).
The reforming gas generated by the reformer 11 is supplied to an
anode side of a fuel cell 113 as fuel for power generation. In the
fuel cell 113, the reforming gas (hydrogen) supplied to the anode
side and air (oxygen) supplied to a cathode side are
electrochemically reacted for power generation. The residual
reforming gas not used in power generation at the fuel cell 113 is
returned to the two-fluid spray burner 11 and used as gas fuel for
burner combustion.
[0269] According to the fuel cell power generation system of
Embodiment 11, the heat source of the reformer 111 is any one of
the two-fluid spray burner 11 of the aforementioned Embodiments 1
to 10. Accordingly, the two-fluid spray burner 11 exerting the
excellent effects as described above can provide, for the reformer
111, an improvement in performance, reduction of the costs and the
like.
[0270] In the above description, the liquid fuel tank 19 includes
only one liquid fuel discharge hole 22, but is not limited to this.
The liquid fuel tank 19 may include a plurality of the liquid
discharge hole 22.
[0271] In the above description, the liquid fuel discharge hole is
provided in the bottom portion of the liquid fuel tank, but is not
limited to this. The liquid fuel discharge hole may be provided in
the side portion of the liquid fuel tank. Specifically, the liquid
fuel tank may be of any type if the liquid fuel tank includes a
cylindrical side portion and a bottom portion provided at the lower
end of the side portion and is configured to store the liquid fuel
supplied from the liquid fuel supply tube and discharge the stored
liquid fuel through the single or the plurality of liquid fuel
discharge holes which are opened below the liquid level of the
stored liquid fuel and which are located in the side or bottom
portion.
[0272] In the above description, the liquid fuel tank is provided
within the sprayer outer cylinder, but is not limited to this. For
example, it may be configured to provide the liquid fuel tank
outside of the sprayer outer cylinder and supply the liquid fuel
discharged from the liquid fuel discharge hole of the liquid fuel
tank, through a tube or the like, to the space where the liquid
fuel converges with the atomizing gas.
[0273] In the above description, the upper end of the liquid fuel
tank is opened to allow pressure of the atomizing air flown into
the atomizing air passage to act on the liquid level of the liquid
fuel stored in the liquid fuel tank, but is not limited to this. It
may be configured so that the upper end of the liquid fuel tank may
be opened to the atmosphere, for example. In other words, the
liquid fuel discharged from the liquid fuel supply tube is once
stored in the liquid fuel tank, and produce a liquid column head of
the liquid fuel by the pressure balance between the inside and
outside (two-fluid converging space portion) of the liquid fuel
tank. Thus, the stored liquid fuel is continuously discharged from
the liquid fuel discharge hole.
[0274] Moreover, in the above description, two swirling-type
grooves and four collision-type grooves are provided. But the
numbers of grooves are not limited to these and may be set proper
numbers. However, in order to secure a uniform spray of the
atomized liquid fuel in circumferential direction, it is desirable
that the number of grooves in swirling-type to be two or more and
collision-type grooves to be three or more.
[0275] As described above, the configuration (invention) of
providing the plate (shielding plate), first cylinder for delaying
supply of combustion air, second cylinder for preventing stagnation
and the like can be applied to not only the aforementioned
two-fluid spray burner which includes a two-fluid sprayer, as a
fuel spray, spraying liquid fuel and atomizing gas. It could also
be applied to a burner including a fuel spray spraying only liquid
fuel or a fuel spray spraying gas fuel.
[0276] Moreover, in the above description, the combustion air holes
are provided on the outer periphery of the plate (shielding plate)
by forming protrusions on the circumference of the plate (shielding
plate) but is not limited to this. The combustion air holes only
have to be provided on the outer periphery of the plate (shielding
plate) and may be provided on the outer periphery of the plate by
opening a hole in the periphery of the plate (shielding plate)
itself, for example.
[0277] In the above description, the plate (shielding plate) is a
horizontal plate but is not limited to this. The plate may be
inclined obliquely downward from the inside towards the outside.
For example, the plate 18 may be shaped in a truncated cone as
virtually indicated by a dashed-dotted line in FIG. 11. Such an
inclined plate can provide not only the function of keeping the
combustion air away from the fuel spray nozzle (two-fluid spray
nozzle 38) but also provide a function of delaying supply of
combustion air, which is similar to the function of the first
cylinder.
INDUSTRIAL AVAILABILITY
[0278] The present invention relates to a burner and is usefully
applied to a case requiring a large amount of combustion exhaust
gas produced to heat a reformer or the like of a large-size fuel
cell power generation system, for example.
* * * * *