U.S. patent application number 17/233740 was filed with the patent office on 2021-11-18 for totally aerated combustion burner.
This patent application is currently assigned to RINNAI CORPORATION. The applicant listed for this patent is RINNAI CORPORATION. Invention is credited to Kazuyuki Akagi.
Application Number | 20210356123 17/233740 |
Document ID | / |
Family ID | 1000005578837 |
Filed Date | 2021-11-18 |
United States Patent
Application |
20210356123 |
Kind Code |
A1 |
Akagi; Kazuyuki |
November 18, 2021 |
Totally Aerated Combustion Burner
Abstract
The air-fuel mixture permeable member is disposed to overlap
that surface of the burner frame which lies opposite to the burner
body. The fixing frame is disposed so as to be fixed to the inner
peripheral portion of the enclosing frame part of the burner frame
by pinching the air-fuel mixture permeable member between the inner
peripheral portion and the fixing frame. The air-fuel mixture
permeable member has an extended part protruding outward beyond the
fixing frame so as to cover by this extended part an outer
peripheral portion of the enclosing frame part.
Inventors: |
Akagi; Kazuyuki; (Aichi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
RINNAI CORPORATION |
Aichi |
|
JP |
|
|
Assignee: |
RINNAI CORPORATION
Aichi
JP
|
Family ID: |
1000005578837 |
Appl. No.: |
17/233740 |
Filed: |
April 19, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F23D 14/145 20130101;
F23D 14/36 20130101; F23D 14/02 20130101; F23D 2900/14001
20130101 |
International
Class: |
F23D 14/14 20060101
F23D014/14; F23D 14/36 20060101 F23D014/36; F23D 14/02 20060101
F23D014/02 |
Foreign Application Data
Date |
Code |
Application Number |
May 13, 2020 |
JP |
2020-084714 |
Claims
1. A totally aerated combustion burner comprising: a burner body
which is supplied inside thereof with an air-fuel mixture; and a
combustion plate part which covers an open surface of the burner
body and through which the air-fuel mixture is ejected, the
combustion plate part being made up of: a burner frame having in a
central part thereof an air-fuel mixture passage region and an
enclosing frame part around the air-fuel mixture passage region;
and an air-fuel mixture permeable member which is made of
heat-resistant fibers and which covers the air-fuel mixture passage
region of the burner frame, the air-fuel mixture passage region of
the burner frame having formed a single opening or a plurality of
openings for the air-fuel mixture to pass therethrough, wherein the
air-fuel mixture permeable member is disposed to overlap that
surface of the burner frame which lies opposite to the burner body;
wherein the combustion plate part further comprises a fixing frame
which is fixed to that inner peripheral portion of the enclosing
frame part of the burner frame which is closer to the air-fuel
mixture passage region, in a manner to sandwich the air-fuel
mixture permeable member between the enclosing frame part of the
burner frame and the fixing frame; and wherein the air-fuel mixture
permeable member has an extended part protruding outward beyond the
fixing frame so that the extended part covers that outer peripheral
portion of the enclosing frame part which is positioned outside the
fixing frame.
2. The totally aerated combustion burner according to claim 1,
wherein a clearance is secured between the outer peripheral portion
of the enclosing frame part and the extended part of the air-fuel
mixture permeable member.
3. The totally aerated combustion burner according to claim 2,
wherein the outer peripheral portion of the enclosing frame part is
provided with a plurality of projected parts at a circumferential
distance from one another so as to secure the clearance by coming
into contact with the extended part of the air-fuel mixture
permeable member.
4. The totally aerated combustion burner according to claim 1,
wherein the air-fuel mixture permeable member is made of non-metal
heat-resistant fibers.
Description
TECHNICAL FIELD
[0001] The present invention relates to a totally aerated
combustion burner having a burner body which is supplied inside
thereof with an air-fuel mixture, and a combustion plate part which
covers an open surface of the burner body and through which the
air-fuel mixture is ejected.
BACKGROUND ART
[0002] As this kind of totally aerated combustion burner, there is
known in patent document 1 an arrangement in which the combustion
plate part is made up of; a burner frame having in a central part
thereof an air-fuel mixture passage region and an enclosing frame
part around the air-fuel mixture passage region; and a member
permeable to the air-fuel mixture (hereinafter called "an air-fuel
mixture permeable region"), the air-fuel mixture permeable member
which is made of heat-resistant fibers and which covers the
air-fuel mixture passage region of the burner frame. In this
arrangement, the burner frame is of a picture frame and has a
single opening in the air-fuel mixture passage region for the
air-fuel mixture to pass therethrough.
[0003] In addition, according to the above-mentioned arrangement,
in order to prevent the burner frame from getting overheated by
heating with convection and radiation heat from the flame to be
formed by the combustion of the air-fuel mixture ejected from the
air-fuel mixture permeable member, the enclosing frame part of the
burner frame is provided with a thermal insulation material in
order to cover the enclosing frame part from the side opposite to
the burner body. By the way, the thermal insulation material is
fixed by a fixing frame that is spot-welded in advance to that
surface of the enclosing frame part which is opposite to the burner
body.
[0004] However, in the above-mentioned arrangement, the fixing
frame and the thermal insulation material are required, bringing
about an increase in the number of parts. Also a step of assembling
the thermal insulation material becomes necessary, resulting in an
obstacle to an attempt to reduce the cost.
PRIOR ART DOCUMENTS
Patent Documents
[0005] Patent Document 1: JP2017-116160A
SUMMARY
Problems that the Invention is to Solve
[0006] In view of the above points, this invention has a problem in
providing a totally aerated combustion burner in which the thermal
insulation material for preventing the overheating of the burner
frame is not necessary so as to be able to attempt a cost
reduction.
Means for Solving the Problems
[0007] In order to solve the above-mentioned problem, this
invention is a totally aerated combustion burner comprising: a
burner body which is supplied inside thereof with an air-fuel
mixture; and a combustion plate part which covers an open surface
of the burner body and through which the air-fuel mixture is
ejected. The combustion plate part is made up of: a burner frame
having in a central part thereof an air-fuel mixture passage region
and an enclosing frame part around the air-fuel mixture passage
region; and an air-fuel mixture permeable member which is made of
heat-resistant fibers and which covers the air-fuel mixture passage
region of the burner frame, the air-fuel mixture passage region of
the burner frame having formed a single opening or a plurality of
openings for the air-fuel mixture to pass therethrough. The
air-fuel mixture permeable member is disposed to overlap that
surface of the burner frame which lies opposite to the burner body.
The combustion plate part further comprises a fixing frame which is
fixed to that inner peripheral portion of the enclosing frame part
of the burner frame which is closer to the air-fuel mixture passage
region, in a manner to sandwich the air-fuel mixture permeable
member between the inner peripheral portion of the enclosing frame
part of the burner frame and the fixing frame. The air-fuel mixture
permeable member has an extended part protruding outward beyond the
fixing frame so that the extended part covers that outer peripheral
portion of the enclosing frame part which is positioned outside the
fixing frame.
[0008] The air-fuel mixture permeable member is made of
heat-resistant fibers and contains therein an air space (cavity).
According to this invention, that extended part of the air-fuel
mixture permeable member which protrudes beyond the fixed frame
functions as a thermal insulating material. Therefore, the burner
frame can be effectively prevented from getting overheated. In
addition, according to this invention, since there is no need of
separately preparing a thermal insulation material, the cost can be
reduced.
[0009] In this invention, a clearance shall preferably be secured
between the outer peripheral portion of the enclosing frame part
and the extended part of the air-fuel mixture permeable member.
According to this arrangement, due to the presence of the air space
inside the clearance, the thermal insulation property relative to
the burner frame can be more improved. By the way, if the outer
peripheral portion of the enclosing frame part is provided with a
plurality of projected parts at a circumferential distance from one
another so as to secure the clearance by coming into contact with
the extended part of the air-fuel mixture permeable member, the
above-mentioned air space can advantageously be stably secured.
[0010] By the way, the heat-resistant fibers that are the material
of the air-fuel mixture permeable member can be made of metal
fibers, but the metal fibers are high in thermal conductivity,
resulting in a decrease in insulation characteristics. On the other
hand, if the air-fuel mixture permeable member is made of non-metal
heat resistant fibers such as SiC and the like, the thermal
conductivity of the heat-resistant fibers becomes low. As a
consequence, the heat insulation property by the extended part of
the air-fuel mixture permeable member can be sufficiently
secured.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a perspective view of a combustion apparatus
equipped with a totally aerated combustion burner according to a
first embodiment of this invention.
[0012] FIG. 2 is a perspective view of the combustion apparatus as
viewed from a side opposite to that in FIG. 1.
[0013] FIG. 3 is a sectional view cut away along the line III-III
in FIG. 1.
[0014] FIG. 4 is a sectional view cut away along the line IV-IV in
FIG. 3.
[0015] FIG. 5 is a perspective view in an exploded state of the
totally aerated combustion burner according to the first
embodiment.
[0016] FIG. 6 is an enlarged sectional view of an essential part in
an assembled state of the combustion plate part in FIG. 5.
[0017] FIG. 7 is an enlarged sectional view of an essential part,
corresponding to FIG. 5, of the combustion plate part of the
totally aerated combustion burner according to a second
embodiment.
PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION
[0018] A combustion apparatus shown in FIGS. 1 through 4 is
provided with: a totally aerated combustion burner 1 according to
an embodiment of this invention, the burner 1 having a burner body
11 which is supplied inside thereof with air-fuel mixture (mixture
gas of fuel gas and primary air), and a combustion plate part 12
which covers a downward open surface 111 of the burner body 11; and
a combustion box 2 having a box flange part 22 at an upper end
thereof, the box flange part 22 being fastened with screws 21 to a
body flange part 112 enclosing an open surface 111 of the burner
body 11. The combustion box 2 has housed therein a heat exchanger 3
for hot water supply.
[0019] The heat exchanger 3 is constituted by a fin-tube type of
heat exchanger provided with a multiplicity of fins 31 and a
plurality of heat-absorbing tubes 32 which penetrate these fins 31.
On an outside surface of side plate 23, 24 on laterally one side
and the opposite side, respectively, of the combustion box 2, there
are provided a plurality of connection covers 33 which define
connection passages of the adjacent two heat absorbing tubes 32, 32
between each of the side plates 23, 24. In this manner, all the
heat-absorbing tubes 32 are connected together in series with one
another. Further, the connection cover 33 defining the connection
passage, which is connected to the heat absorbing tubes 32 on an
upstream end of the heat exchanger 3, between the side plates 24 of
the laterally opposite side are provided with a water inlet 34.
[0020] Furthermore, on an inside of that portion of a rear-side
side plate 25 of the combustion box 2 which is above the heat
exchanger 3, there are disposed vertically arranged three pieces of
first water passages 5.sub.1 made up of tubes in a manner to
contact the side plate 25. Also on an inside of that portion of a
front-side side plate 26 of the combustion box 2 which is above the
heat exchanger 3, there are also disposed vertically arranged three
pieces of third water passages 5.sub.3 made up of tubes in a manner
to contact the side plate 26. In addition, on an outside surface of
the laterally one-side side plate 23 of the combustion box 2, there
are connected: an inlet-side header cover 51 defining, together
with the side plate 23, a connection passage which connects the
vertically disposed three pieces of first water passages 5.sub.1 to
the heat absorbing tube 32 on a downstream end of the heat
exchanger 3; and an outlet side header cover 52 defining, together
with the side plate 23, a connection passage for the vertically
arranged three pieces of third water passages 5.sub.3. The outlet
side header cover 52 is provided with a hot water outlet 53.
[0021] Furthermore, as shown in FIGS. 2 and 3, the laterally
opposite-side side plate 24 of the combustion box 2 is provided
with second water passages 5.sub.2 which connect the rear side
first water passages 5.sub.1 and the front side third water
passages 5.sub.3. Each of the second water passages 5.sub.2 is made
up of: a laterally inward dent which is formed in the side plate
24; and a cover 54 which is mounted on an outside surface of the
side plate 24 in a manner to cover the dent. It is thus so
arranged: that the water to be supplied from the water inlet 34 is
heated by the heat exchanger 3; and that the heated water flows out
of the hot water outlet 53 through the connection passage inside
the inlet-side header cover 51, the first water passages 5.sub.1,
the second water passages 5.sub.2, the third water passages
5.sub.3, and the connection passage inside the outlet-side header
cover 52. In addition, the laterally one-side side plate 23 of the
combustion box 2 is provided with a fourth water passage 54 which
extends rearward, from an upper portion, of the connection passage
inside the outlet-side header cover 52, the fourth water passage 54
being constituted by: a laterally inward dent which is formed in
the side plate 23; and a cover 52a which covers this dent and which
is integral with the outlet-side header cover 52. It is thus so
arranged that each of the side plates 23-26 of the combustion box 2
is cooled by the water which flows through these first through
fourth water passages 5.sub.1-5.sub.4.
[0022] Further, the front-side side plate 26 of the combustion box
2 has mounted thereon electrode parts 6 having an ignition
electrode 61, a grounding electrode 62, and a flame rod 63 which
are protruded through the side plate portion between the two, i.e.,
the first and the second from the top, of the third water passages
5.sub.3, 5.sub.3 into the combustion box 2. The electrode parts 6
are additionally provided with an inspection window 64 through
which the inside of the combustion box 2 can be visually
inspected.
[0023] Detailed description will now be made of the totally aerated
combustion burner 1. The burner body 11 has opened therethrough an
inlet port 113 for connecting thereto a fan 4 which supplies
air-fuel mixture. The inlet port 113 has mounted thereon a check
valve 13 which prevents the air-fuel mixture remaining inside the
burner body 11 from flowing backward to the side of the fan 4, at
the time of stopping of the fan 4. The check valve 13 is made up
of; a resin-made valve box 131 which is built into the inlet port
113; and a resin-made valve plate 132 which is rotatably mounted,
so as to be opened or closed, in that opening of the valve box 131
which faces inward of the burner body 11.
[0024] With reference also to FIGS. 5 and 6, the combustion plate
part 12 is made up of; a burner frame 121 of a sheet-metal make,
having in a central part thereof an air-fuel mixture passage region
121a, and an enclosing frame part 121b around the air-fuel mixture
passage region 121a, and an air-fuel mixture permeable member 122
made of heat-resistant fibers and which covers the air-fuel mixture
passage region 121a of the burner frame 121. The air-fuel mixture
passage region 121a of the burner frame 121 of this embodiment has
formed therein a plurality of openings 121a' made up of small holes
through which the air-fuel mixture passes. The air-fuel mixture
permeable member 122 is constituted by a knit fabric or felted
non-woven fabric of heat-resistant fibers, and is disposed so as to
overlap that surface (lower surface) of the burner frame 121 which
is on the side opposite to the burner body 11. The air-fuel mixture
supplied into the burner body 11, after having passed through the
openings 121a', permeates through the air-fuel mixture permeable
member 122 for ejection to perform totally aerated combustion.
[0025] In an outer periphery of the enclosing frame part 121b of
the burner frame 121, there is formed a frame flange part 121d,
extended (or protruding) outward, including a stepped part 121c
that is bent toward the burner body 11 side (upward). In this
arrangement, the frame flange part 121d is sandwiched between the
body flange part 112 and the box flange part 22, and further a
packing 7 is interposed between the frame flange part 121d and the
body flange part 112, thereby securing sealing properties. By the
way, as clearly shown in FIG. 4, the air-fuel mixture passage
region 121a and the enclosing frame part 121b of the burner frame
121 are curved into an arcuate shape in cross section in the
front-to-back direction. Similarly, the air-fuel mixture permeable
member 123 is also curved into an arcuate shape in cross section in
the front-to-back direction.
[0026] Now, in case overheating happens to the burner frame 121 due
to the heating by convection and radiation heat from the flame to
be formed by the combustion of the air-fuel mixture, when the heat
transfers from the burner frame 121 to the burner body 11, the
burner body 11 will be elevated to a considerably high temperature.
As a consequence, a bad effect will be inflicted on the check valve
13 which is an accessory part to the burner body 11. In this case,
in order to impede the heat transmission from the burner frame 121
to the burner body 11, it is considered to make the packing 7 of a
ceramic packing that is superior in thermal insulation
characteristics. This solution, however, brings about a higher
cost. In order to enable to use an ordinary packing as the packing
7, it becomes necessary to prevent the burner frame 121 from
getting overheated.
[0027] Therefore, in this embodiment, the combustion plate part 12
further comprises a fixing frame 123 which is fixed to an inner
peripheral portion 121bin, near the air-fuel mixture passage region
121a, of the enclosing frame part 121b of the burner frame 121, in
a manner to sandwich the air-fuel mixture permeable member 122
between the inner peripheral portion 121bin of the enclosing frame
part 121b of the burner frame 121 and the fixing frame 123. The
fixing frame 123 is circular and is provided, at a
circumferentially plurality of positions thereof, with drawn parts
123a which protrude toward the burner frame 121 side (i.e.,
upward). In this arrangement, by inserting these drawn parts 123a
into each of holes 122a formed in the air-fuel mixture permeable
member 122, the drawn parts 123a are then spot-welded to the inner
peripheral portion 121bin of the enclosing frame part 121b. The
fixing frame 123 is thus fixed to the inner peripheral portion
121bin of the enclosing frame part 121b. According to this
arrangement, the air-fuel mixture permeable member 122 will be
sandwiched between the enclosing frame part 121b and the fixing
frame 123 at a portion other than drawn parts 123a of the fixing
frame 123.
[0028] The air-fuel mixture permeable member 122 is provided with
an extended part 122b that protrudes outward beyond the fixing
frame 123. It is thus so arranged that the extended part 122b
covers that outer peripheral portion 121bout of the enclosing frame
part 121b which is positioned outside the fixing frame 123. It is
to be noted that the air-fuel mixture permeable member 122 is made
of heat-resistant fibers and contains therein air space (cavity).
Therefore, that extended part 122b of the air-fuel mixture
permeable member 122 which covers the outer peripheral portion
121bout of the enclosing frame part 121b functions as the thermal
insulation material. Overheating of the burner frame 121,
specifically an excessive temperature rise of the frame flange part
121d of the burner frame 12, can effectively be prevented.
Therefore, it is not necessary to use, as the packing 7, an
expensive one that is superior in thermal insulation property.
Further, an insulation material need not be specially provided for
the purpose of preventing the burner frame 121 from getting
overheated, thereby contributing to the cost reduction.
[0029] By the way, it is also possible to replace the
heat-resistant fibers as the material for the air-fuel mixture
permeable member 122 with metal fibers. However, metal fibers are
high in thermal conductivity and the thermal insulation property
lowers. Therefore, the air-fuel mixture permeable member 122 shall
preferably be made to be heat-resistant fibers of non-metal such as
SiC and the like. According to this arrangement, since the thermal
conductivity of the heat-resistant fibers becomes lower, thermal
insulation property by the extended part 122b of the air-fuel
mixture permeable member 122 can advantageously be sufficiently
secured.
[0030] Further, according to the second embodiment as shown in FIG.
7, the following arrangement may also be made, i.e., the extended
part 122b of the air-fuel mixture permeable member 122 is made to
offset in a direction away from the burner frame 121 (i.e.,
downward) relative to the remaining portion of the air-fuel mixture
permeable member 122 so that a clearance 124 may be disposed
between the extended part 122b and the outer peripheral portion
121bout of the enclosing frame part 121b. According to this
arrangement, due to the presence of the air space (cavity) in the
clearance 124, the thermal insulation property relative to the
burner frame 121 can all the more be improved. Furthermore,
according the second embodiment, in the outer peripheral portion
121bout of the enclosing frame part 121b, there are provided a
plurality of projections 121e which are intended to secure the
above-mentioned clearance 124 as a result of abutment with the
extended part 122b of the air-fuel mixture permeable member 122.
According to this arrangement, the above-mentioned clearance 124
can advantageously be stably secured.
[0031] Descriptions have so far been made of the embodiments of
this invention with reference to the figures, but this invention
shall not be limited to the above. For example, in the
above-mentioned embodiments, the burner frame 121 has formed
therein a plurality of openings 121a' made up of small holes.
However, it is also possible to form a single opening over the
entire region in the air-fuel mixture passage region 121a. In this
case, there may be arranged such that a distribution plate in which
a plurality of small holes corresponding to the openings 121a' in
the above-mentioned embodiment overlap that surface of the air-fuel
mixture permeable member 122 which lies on the burner frame 121
side. In addition, in the above-mentioned embodiment, the burner
frame 121 is made of a metal plate, it may alternatively be made of
a material other than the metal plate such as made of aluminum
die-cast product and the like. Further, the totally aerated
combustion burner according to the above-mentioned embodiment is
disposed such that the open surface 111 of the burner body 11 faces
down. However, this invention is similarly applicable to the
totally aerated combustion burner disposed such that the open
surface 111 thereof faces up.
EXPLANATION OF MARKS
[0032] 1 totally aerated combustion burner [0033] 11 burner body
[0034] 111 open surface [0035] 12 combustion plate part [0036] 121
burner frame [0037] 121a air-fuel mixture passage region [0038]
121a' opening [0039] 121b enclosing frame part [0040] 121bin inner
peripheral portion [0041] 121bout outer peripheral portion [0042]
121e projected part [0043] 122 air-fuel mixture permeable member
[0044] 123 fixing frame [0045] 124 clearance
* * * * *