U.S. patent application number 15/414051 was filed with the patent office on 2017-07-27 for hot water supply device.
This patent application is currently assigned to NORITZ CORPORATION. The applicant listed for this patent is NORITZ CORPORATION. Invention is credited to Ryo HASEGAWA, Shota MIZUNO.
Application Number | 20170211844 15/414051 |
Document ID | / |
Family ID | 59358986 |
Filed Date | 2017-07-27 |
United States Patent
Application |
20170211844 |
Kind Code |
A1 |
MIZUNO; Shota ; et
al. |
July 27, 2017 |
HOT WATER SUPPLY DEVICE
Abstract
A hot water supply device includes a heat exchanger, a
temperature detection sensor detecting the surface temperature of
the heat exchanger, and a fixing fitting fixing the sensor to a
casing of the heat exchanger. The heat exchanger includes heat
exchange tubing, a plurality of fins brazed to the heat exchange
tubing, and the casing within which the tubing and the fins are
housed, and to which both end portions of each of the fins are
brazed. The fixing fitting includes a sensor fixing portion to
which the temperature detection sensor is fixed, and fitting fixing
portions attached to the casing. A predetermined gap is defined
between the sensor fixing portion and the casing. The fitting
fixing portions are brazed to an outer surface portion of the
casing corresponding to the outside of a portion thereof where the
casing and one or a plurality of the fins are brazed together.
Inventors: |
MIZUNO; Shota; (Kobe-shi,
JP) ; HASEGAWA; Ryo; (Kobe-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NORITZ CORPORATION |
Hyogo |
|
JP |
|
|
Assignee: |
NORITZ CORPORATION
Hyogo
JP
|
Family ID: |
59358986 |
Appl. No.: |
15/414051 |
Filed: |
January 24, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F24H 1/145 20130101;
F24H 9/18 20130101 |
International
Class: |
F24H 1/14 20060101
F24H001/14; F24H 9/18 20060101 F24H009/18 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 27, 2016 |
JP |
2016-013767 |
Claims
1. A hot water supply device comprising a burner unit, a heat
exchanger for applying heat to water with combustion gases supplied
from the burner unit, a temperature detection means for detecting a
surface temperature of the heat exchanger, and a fixing fitting for
fixing the temperature detection means on the heat exchanger,
characterized in that: the burner unit includes a plurality of
combustion tubes disposed in a predetermined arranging direction,
with the plurality of combustion tubes including at least one usual
combustion tube that is always performing combustion while hot
water being supplied; the heat exchanger comprises a heat exchange
tubing through which hot water flows, a plurality of fins that are
brazed to the heat exchange tubing, and a heat exchanger casing
that houses the heat exchange tubing and the plurality of fins and
to an inner surface of which both end portions of each of the
plurality of fins are brazed; the heat exchange tubing comprises a
plurality of straight pipe portions that extend in the arranging
direction and that are arranged so as to be spaced apart at
predetermined intervals in a direction orthogonal to the arranging
direction, connected together by a plurality of U-shaped link
tubes; the fixing fitting comprises a sensor fixing portion to
which the temperature detection means is fixed, and a fitting
fixing portion that are fixed to an outer surface of the heat
exchanger casing; and along with a predetermined gap being defined
between the sensor fixing portion and the outer surface of the heat
exchanger casing, the fitting fixing portion is brazed to the outer
surface of the heat exchanger casing that corresponds to an
exterior portion where the heat exchanger casing and one or a
plurality of fins are brazed together.
2. A hot water supply device according to claim 1, characterized in
that: the heat exchange tubing comprises a lower heat exchange
tubing that is disposed so as directly to oppose the burner unit
from above, and an upper heat exchange tubing that is disposed
above the lower heat exchange tubing and that applies heat to hot
water heated by the lower heat exchange tubing; and the fixing
fitting is provided in a position on the outer surface of the heat
exchanger casing so as to correspond to the most downstream side in
the direction of hot water flow in the lower heat exchange tubing,
and so as to correspond to the usual combustion tube.
3. A hot water supply device according to claim 1, characterized in
that the fixing fitting comprises a projecting lug that projects
upward from an upper edge of the fitting fixing portion.
4. A hot water supply device according to claim 1, characterized in
that the fixing fitting comprises a pair of flanges that extend
from both upper and lower edges of the sensor fixing portion,
horizontally in a direction departing from the heat exchanger
casing.
5. A hot water supply device according to claim 4, characterized in
that a protective cover that protects the sensor fixing portion and
the temperature detection means is attached to the fixing fitting
via the pair of flanges.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a hot water supply device,
and more particularly relates to such a device in which a
construction is improved for attaching, to a heat exchanger casing,
a temperature detection means that detects the temperature of the
heat exchanger casing.
[0002] From the prior art, hot water supply devices of various
types have been widely applied in general household use for
provision of hot water, and these include gas hot water supply
devices, electric hot water supply devices, fuel oil hot water
supply devices, and so on. In particular, a gas powered hot water
supply device is per se known comprising a blower fan that sucks in
air for combustion from the exterior, a burner unit that mixes the
combustion air with fuel gas and combusts the mixture, a heat
exchanger that heats up cold water by exchanging heat between the
combustion gas which is at high temperature and the cold water
which flows in a heat exchange tubing, an exhaust pipe for
discharging the exhaust to the exterior after heat exchange, and so
on.
[0003] As the heat exchanger described above, a fin-and-tube type
heat exchanger is generally applied that includes a heat exchange
tubing made from copper and a plurality of fins also made from
copper that are fixed to the heat exchange tubing so as to be
capable of transferring heat thereto; and a temperature detection
means that detects the temperature of the heat exchanger is also
commonly provided (refer to Patent Document #1).
[0004] Now, when tap water whose hardness is high is employed as
the supply of fresh water to the heat exchanger, scale is formed
due to combination of calcium and/or magnesium or the like and
carbonate ions and/or sulfate ions or the like contained in the tap
water, and scale clogging takes place due to undesirable
accumulation of this scale within the heat exchange tubing of the
heat exchanger, so that the heat exchange efficiency of the heat
exchanger is deteriorated. Moreover, when the hot water supply
device is used over the long term, fin clogging may also occur due
to soot adhering to the fins of the heat exchanger, and this also
causes deterioration of the heat exchange efficiency of the heat
exchanger.
[0005] If use of the hot water supply device is to be continued in
the state in which scale clogging and/or fin clogging has taken
place, then it is necessary to perform maintenance in order to
remove the scale and/or the soot, since there is an anxiety of
damage to the heat exchanger if an anomaly such as scale clogging
or fin clogging has occurred. Due to this, in the prior art, a
technique has been employed of detecting the temperature of the
heat exchanger with a temperature detection means, and of detecting
anomaly such as clogging by scale based on this detected
temperature.
[0006] As related technology, in unpublished Japanese Patent
Application 2014-108508, the applicant of the present application
has proposed a sensor fixing fitting for attaching, to the front
surface of the casing of a fin-and-tube type heat exchanger, a
temperature detection means that detects the temperature of the
front surface of the casing. As shown in FIG. 10, the sensor fixing
fitting 100 comprises a holding plate portion 101, a fixing portion
102, a pressing portion 103, a signal line holding portion 104, and
a pair of attachment lugs 105 and an engagement clip 106 that
extend downward from the holding plate portion 101, all of which
are made from thin stainless steel plate.
[0007] The heat exchanger 108 is disposed above the burner casing
107. And the sensor fixing fitting 100 is positioned in a position
near the front surface of the casing 109 of the heat exchanger 108,
and is fixed by the pair of attachment lugs 105 and the engagement
clip 106 being engaged to an engagement portion 111 of a flange 110
of the casing 109. The sensor main body 121 of the temperature
detection sensor 120 is disposed between the outer surface of the
casing 109 and the pressing portion 103, and is pressed by the
pressing portion 103 so as to be contacted against the outer
surface of the casing 109. A positioning portion 122 of the
temperature detection sensor 120 is fitted over a protruding lug
102a of the fixing portion 102, so that the signal line 123 of the
detection sensor 120 is held by the signal line holding portion
104.
[0008] Attention is drawn to Japanese Laid-Open Patent Publication
2015-114004 as a prior art document.
[0009] However when, on the assembly line for this hot water supply
device, the above described temperature detection sensor is to be
attached to the casing, the sensor fixing fitting is attached to
the casing by hand, and the sensor is attached in the state in
which the sensor main body is sandwiched between the outer surface
of the casing and the pressing portion. At this time, in some
cases, variation may occur between different production examples of
the hot water supply device, even though they are of the same type,
due to the fact that the pressure exerted by the pressing portion
is not fixedly determined.
[0010] Since the temperature that is detected varies when the state
of contact between the main body of the temperature detection
sensor and the outer surface of the casing varies, accordingly
error of the detection temperature of the temperature detection
sensor may take place due to the variation described above of the
pressure exerted by the pressing portion, and thus it is difficult
to stabilize the temperature detection performance of the
temperature detection sensor.
[0011] The object of the present invention is to provide a hot
water supply device that is capable of ensuring the stability of
the temperature detection performance of a temperature detection
means.
SUMMARY OF THE INVENTION
[0012] The present invention presents a hot water supply device
comprising a burner unit, a heat exchanger for applying heat to
water with combustion gases supplied from the burner unit, a
temperature detection means for detecting a surface temperature of
the heat exchanger, and a fixing fitting for fixing the temperature
detection means on the heat exchanger, characterized in that: the
burner unit includes a plurality of combustion tubes disposed in a
predetermined arranging direction, with the plurality of combustion
tubes including at least one usual combustion tube that is always
performing combustion while hot water being supplied; the heat
exchanger comprises a heat exchange tubing through which hot water
flows, a plurality of fins that are brazed to the heat exchange
tubing, and a heat exchanger casing that houses the heat exchange
tubing and the plurality of fins and to an inner surface of which
both end portions of each of the plurality of fins are brazed; the
heat exchange tubing comprises a plurality of straight pipe
portions that extend in the arranging direction and that are
arranged so as to be spaced apart at predetermined intervals in a
direction orthogonal to the arranging direction, connected together
by a plurality of U-shaped link tubes; the fixing fitting comprises
a sensor fixing portion to which the temperature detection means is
fixed, and a fitting fixing portion that are fixed to an outer
surface of the heat exchanger casing; and along with a
predetermined gap being defined between the sensor fixing portion
and the outer surface of the heat exchanger casing, the fitting
fixing portion is brazed to the outer surface of the heat exchanger
casing that corresponds to an exterior portion where the heat
exchanger casing and one or a plurality of fins are brazed
together.
[0013] In a desirable first aspect of the present invention, the
heat exchange tubing comprises a lower heat exchange tubing that is
disposed so as directly to oppose the burner unit from above, and
an upper heat exchange tubing that is disposed above the lower heat
exchange tubing and that applies heat to hot water heated by the
lower heat exchange tubing; and the fixing fitting is provided in a
position on the outer surface of the heat exchanger casing so as to
correspond to the most downstream side in the direction of hot
water flow in the lower heat exchange tubing, and so as to
correspond to the usual combustion tube.
[0014] In a desirable second aspect of the present invention, the
fixing fitting comprises a projecting lug that projects upward from
an upper edge of the fitting fixing portion.
[0015] In a desirable third aspect of the present invention, the
fixing fitting comprises a pair of flanges that extend from both
upper and lower edges of the sensor fixing portion, horizontally in
a direction departing from the casing.
[0016] In a desirable fourth aspect of the present invention, a
protective cover that protects the sensor fixing portion and the
temperature detection means is attached to the fixing fitting via
the pair of flanges.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a rough structural diagram showing a hot water
supply device according to an embodiment of the present
invention;
[0018] FIG. 2 is an elevation view of a sensible heat exchanger and
of a latent heat exchanger;
[0019] FIG. 3 is a horizontal sectional plan view showing a lower
heat exchange tubing, a heat exchanger casing, and fins of the
sensible heat exchanger;
[0020] FIG. 4 is a horizontal sectional plan view showing an upper
heat exchange tubing, the heat exchanger casing, and fins of the
sensible heat exchanger;
[0021] FIG. 5 is a perspective view of a fixing fitting that is
attached to the outer surface of a casing of the sensible heat
exchanger, and of a temperature detection sensor that is attached
to the fixing fitting;
[0022] FIG. 6 is a perspective view of essential portions, showing
a state in which the fixing fitting, a protective cover, and the
temperature detection sensor are attached to the casing;
[0023] FIG. 7 is a perspective view of essential portions, showing
a state in which the fixing fitting and the temperature detection
sensor are attached to the casing;
[0024] FIG. 8 is a perspective view of the protective cover;
[0025] FIG. 9 is a perspective view of the fixing fitting; and
[0026] FIG. 10 is a figure corresponding to FIG. 5, relating to an
unpublished prior art.
DETAILED DESCRIPTION
[0027] In the following, an embodiment of the present invention
will be described with reference to the drawings. First, the
overall structure of a hot water supply device 1 will be explained.
The hot water supply device 1 is an apparatus that may be applied
as a device for supplying heat to a hot water heating system or a
room heating device or the like, and, as shown in FIG. 1, is built
as a gas hot water supply unit that supplies hot water by utilizing
heat generated by combustion of fuel gas for heating of cold or
warm water.
[0028] This hot water supply device 1 comprises a blower fan 2 for
supplying air for combustion, a burner section 3 for combusting
fuel gas, a heat exchanger section 4 that exchanges heat between
the combustion gases generated by the burner section 3 and cold
water, an exhaust vent 5 that discharges the combustion gases after
heat exchange by the heat exchanger section 4, conduits of various
types such as a cold water intake pipe 6a and a hot water output
pipe 6b and so on, a control unit 7 that receives signals from
various sensors and controls the operation of devices of various
types, and the like.
[0029] Next, the burner section 3 will be explained.
[0030] As shown in FIGS. 1 and 2, the burner section 3 comprises a
burner unit 11 that mixes together and combusts fuel gas supplied
from a fuel supply conduit (not shown) and combustion air supplied
from the blower fan 2, a burner casing 12 that contains the burner
unit 11, a combustion space 13 defined within the burner casing 12
above the burner unit 11, and so on. The burner casing 12 is formed
in the shape of a rectangular parallelepiped, and is open at the
top. The blower fan 2 is provided at the lower portion of the
burner casing 12.
[0031] As shown in FIGS. 1 and 2, the burner unit 11 comprises a
plurality of combustion tubes 11a that are arranged in parallel so
as to extend in the front to back direction and are disposed in
sequence in a predetermined arranging direction (left to right
direction); for example, the burner unit 11 may be built as a
multi-stage unit having six combustion stages (i.e. combustion
regions) #1 through #6, and combustion operation may be performed
by changing over to one or more of the combustion stages #1 through
#6, according to the required capacity for supply of hot water. The
respective numbers of combustion tubes in each of the combustion
stages #1 through #6 may, for example, be 2, 3, 5, 7, 12, and 17.
Each of the plurality of combustion tubes 11a is connected to a
fuel supply conduit. Combustion operation by each of the combustion
stages #1 through #6 is controlled by the control unit 7. It should
be noted that, in normal conditions, the combustion stage which is
most frequently used is the combustion stage #2. Three combustion
tubes 11a of the combustion stage #2 are usual combustion tubes
that are always performing combustion while hot water being
supplied.
[0032] As shown in FIG. 2, an igniter 15 and a flame rod 16 are
provided in the combustion space 13 above the portion of the burner
unit 11 that corresponds to the combustion stage #1. The igniter 15
and the flame rod 16 are attached to the front wall of the burner
casing 12.
[0033] The igniter 15 is a device for igniting the fuel-air mixture
gases supplied from the burner unit 11 by generating an ignition
spark between itself and an ignition target that is provided to the
burner unit 11, and is mounted so as to project into the combustion
space 13 while extending obliquely downward.
[0034] The flame rod 16 is a device that applies a voltage to the
flame during combustion operation of the burner unit 11; whether or
not a flame is present is detected by detecting electrical current
flowing from the flame rod 16 to the flame.
[0035] Next, the heat exchanger section 4 will be explained.
[0036] As shown in FIGS. 1 and 2, the heat exchanger section 4
comprises a sensible heat exchanger 17 that mainly recovers
sensible heat from the combustion gases, a latent heat exchanger 19
that mainly recovers latent heat from the combustion gases (i.e.
from the exhaust) after heat exchange by the heat exchanger 17, a
lower casing 18 that houses a heat exchange tubing 25 and a
plurality of fins 26 of the heat exchanger 17, an upper casing 20
that houses the latent heat recovery heat exchanger 19, and so
on.
[0037] As shown in FIGS. 3 through 5, the lower casing 18 is built
as a rectangular case, with a flange 21 at the lower end of the
casing 18 and a flange 22 at the upper end of the burner casing 12
being connected together by caulking and/or by screws.
[0038] As shown in FIGS. 1 and 2, the upper casing 20 is formed in
the shape of a rectangular parallelepiped, and has a tray 6d at its
bottom portion for retrieval of condensate (drained water)
generated due to latent heat recovery and also an exhaust intake
passage 24 that opens to its interior, and is also provided with an
exhaust vent 5, at a lower left side surface portion of the upper
casing 20 that corresponds to the front surface of the hot water
supply device 1, for discharging the exhaust to the exterior of the
hot water supply device 1 after heat exchange.
[0039] The lower end portion of the upper casing 20 and the upper
end portion of the lower casing 18 are connected together by
caulking and/or by screws. As shown in FIG. 2, a temperature fuse
23 that is capable of detecting anomalous high temperature is
provided around the periphery of the lower portion of the casing
18, for detecting leakage of exhaust from the casing 18. The
temperature fuse 23 is attached to the flange 21 by a plurality of
fuse fixing fittings 23a.
[0040] Next, the sensible heat exchanger 17 will be explained.
[0041] As shown in FIGS. 2 through 4, the sensible heat exchanger
17 is a fin-and-tube type heat exchanger that comprises the heat
exchange tubing 25, a plurality of fins 26 that are fixed to the
heat exchange tubings 25 so that heat can be transferred
therebetween, and so on.
[0042] The heat exchange tubing 25 includes a lower heat exchange
tubing 25A that is disposed in the lower portion of the sensible
heat exchanger 17 and extends horizontally, and an upper heat
exchange tubing 25B that is disposed in the upper portion of the
sensible heat exchanger 17 and also extends horizontally. The lower
heat exchange tubing 25A is formed by a plurality of straight pipes
27a through 27d that are connected together in series by U-shaped
connection bends 28. And the upper heat exchange tubing 25B is
formed by a plurality of straight pipes 27e through 27h that are
connected together in series by other U-shaped connection bends
28.
[0043] The plurality of fins 26 of the sensible heat exchanger 17
are made as vertical thin plates having almost the same size in the
vertical direction as that of the casing 18, and are arranged
parallel to one another with small gaps being left between them in
the horizontal direction. Flanges 26a at the front and back end
portions of the fins 26 are fixed to the inner surfaces of the
front wall 18a and of the rear wall 18b of the casing 18 by
brazing. The straight pipes 27a through 27h are arranged so as to
pass through apertures formed in the plurality of fins 26, and the
straight pipes 27a through 27h are brazed to the edges of these
apertures in the plurality of fins. It should be understood that,
although the heat exchange tubing 25 and the fins 26 are
manufactured from copper, the material from which they are made is
not necessarily limited; they could also be made from stainless
steel, for example.
[0044] Together with fuel gas supplied to the burner unit 11 from
the fuel supply conduit, air for combustion is also supplied from
the blower fan 2, and the resulting fuel-air mixture gases in which
the fuel gas and the air are mixed together is combusted in the
combustion space 13. The combustion gases that is generated at this
time is conducted upward from the combustion space 13 into the
interior of the casing 18 and becomes cooler as it supplies heat to
fresh water in the sensible heat exchanger 17, and then is
exhausted from the casing 18 via the intake passage 24 and is
conducted into the interior of the upper casing 20.
[0045] After cold water has been warmed by the latent heat recovery
heat exchanger 19, it is supplied to the sensible heat exchanger 17
as shown by the arrow A in FIG. 3, and flows into the interior of
the upper heat exchange tubing 25B after having flowed through the
interior of the lower heat exchange tubing 25A, and this water is
heated by the sensible heat of the combustion gases while passing
through the sensible heat exchanger 17 as described above and
becomes hot water, which is then sent out from the hot water output
pipe 6b to the exterior of the hot water supply device 1, as shown
by the arrow B in FIG. 4.
[0046] Next, a temperature detection sensor 30 for detecting the
temperature of the surface of the casing 18 (i.e. temperature
detection means) and a fixing fitting 40 for attaching the
temperature detection sensor 30 to a portion in the vicinity of the
surface of the front wall 18a of the casing 18 will be
explained.
[0047] As shown in FIGS. 2 and 3, the fixing fitting 40 to which
the temperature detection sensor 30 is attached is provided at a
position that, among the various portions in the vicinity of the
surface of the front wall 18a of the casing 18, is a position that
corresponds to a portion of the lower heat exchange tubing 25A of
the heat exchange tubing 25, which directly opposes the upper side
of the combustion space of the burner section 3, that is at the
most downstream side in the flow direction of the hot water (i.e.
the straight pipe 27d), and that corresponds to the combustion
region whose frequency of use for combustion operation is the
highest (i.e. the combustion stage #2). This is in order to detect
a temperature that reflects the temperature of the heat exchange
tubing 25 at its location where the frequency of thermal load is
the highest (i.e. at its location where most scale and/or soot
accumulate).
[0048] As shown in FIGS. 5 through 9, the fixing fitting 40
comprises a sensor fixing portion 41 that is parallel to the front
wall 18a of the casing 18, a pair of left and right leg portions
42a, 42b, a pair of left and right fitting fixing portions 43a, 43b
that are parallel to the front wall 18, a pair of left and right
projecting lugs 44a, 44b, and a pair of upper and lower rotation
prevention flanges 45a, 45b, and is formed from copper plate as an
integral member.
[0049] The sensor fixing portion 41 is a portion that is adapted
for the temperature detection sensor 30 to be attached to its outer
surface, and is formed in the shape of a flat narrow rectangular
plate that is long in the left to right direction. A screw hole 41a
is formed in the right end portion of the sensor fixing portion 41.
The pair of left and right leg portions 42a, 42b are elements for
defining a predetermined gap S between the sensor fixing portion 41
and the front wall 18a of the casing 18, and they extend rearward
for a predetermined length from the left and right end portions of
the sensor fixing portion 41.
[0050] The pair of left and right fitting fixing portions 43a, 43b
are elements by which the fixing fitting 40 is attached to the
front wall 18a of the casing 18 by brazing, and they project from
the pair of left and right leg portions 42a, 42b towards their
opposite sides from the sensor fixing portion 41. Moreover, the
pair of left and right projecting lugs 44a, 44b are elements for
setting the brazing filler material with their upwardly facing
inclined surfaces, and they extend obliquely upward and forward
from the upper edges of the pair of left and right fitting fixing
portions 43a, 43b respectively.
[0051] The pair of upper and lower rotation prevention flanges 45a,
45b are elements for, when the temperature sensor 30 is attached
with a screw 33, restraining the temperature detection sensor 30 so
that it does not rotate, and also are for enabling a protective
cover 50 that will be described hereinafter to be installed, and
they project horizontally forward from the upper and lower edges of
the sensor fixing portion 41.
[0052] The temperature sensor 30 is, for example, an element
comprising a thermistor that is sealed in a sealing mass 30a made
from a ceramic material, with a position determination portion 31
made as an annular metallic plate being formed at its one end
portion, while a harness 32 of a signal line extends leftward from
its other end portion.
[0053] When the fixing fitting 40 is to be attached by brazing to
the front wall 18a of the casing 18, the fixing fitting 40 is held
at a predetermined attachment position on the front wall 18a by a
jig not shown in the figures, the pair of fitting fixing portions
43a, 43b are held in the state of contacting against the front wall
18a of the casing 18, some brazing filler material is set on the
upwardly facing inclined surfaces of the pair of projecting lugs
44a, 44b, and, simultaneously with the junction portions between
the heat exchange tubing 25 and the plurality of fins 26 of the
heat exchanger 17 and the junction portions between the flanges 26a
at the front and rear ends of the plurality of fins 26 and the
inner surface of the casing 18 and so on being brazed by brazing in
a furnace, also the pair of fitting fixing portions 43a, 43b are
fixed by the brazing filler material to the front wall 18a of the
casing 18 by brazing in the furnace.
[0054] After the brazing in the furnace has been completed, the
temperature detection sensor is positioned in the state of being
contacted against the outer surface of the sensor fixing portion
41, and its position determination portion 31 is fixed with a screw
33 to the sensor fixing portion 41.
Subsequently, the protective cover 50 is attached so as to cover
the sensor fixing portion 41 and the temperature detection sensor
30. This protective cover 50 is an element for protecting the mass
30 of ceramic that seals over the temperature detection sensor
30.
[0055] The protective cover 50 comprises a flat plate portion 51
that coves over the front surface of the temperature detection
sensor 30 from the front, a pair of engagement clips 52, 53 that
extend rearward from the upper and lower edges of the flat plate
portion 51, and a stopper portion 54 that extends rearward from the
right edge of the flat plate portion 51, and is formed integrally
from a thin plate made from stainless steel which is elastic.
[0056] The upper engagement clip 52 has an engagement claw 52a at
its rear end portion that is turned back forward and downward, and
this upper engagement clip 52 extends rearwards along the upper
surface of the upper flange 45a, with its engagement claw 52a being
engaged with and clamped to the rear surface of the sensor fixing
portion 41. Similarly, the lower engagement clip 53 has an
engagement claw 53a at its rear end portion that is turned back
forward and upward, and this lower engagement clip 53 extends
rearwards along the lower surface of the lower flange 45b, with its
engagement claw 53a being engaged with and clamped to the rear
surface of the sensor fixing portion 41.
[0057] In the state in which the fixing fitting 40 is fixed to the
outer surface of the front wall 18a of the casing 18 and the
temperature detection sensor 30 is attached to the outer surface of
the sensor fixing portion 41, a predetermined clearance S (for
example, around 5 to 10 mm) is defined between the rear surface of
the sensor fixing portion 41 and the outer surface of the front
wall 18a of the casing 18.
[0058] Next, the operation and the beneficial effects of the fixing
fitting 40 and the temperature detection sensor 30 of the hot water
supply device 1 will be explained.
[0059] The fixing fitting 40 has the sensor fitting portion 41
which is separated by the clearance S from the outer surface of the
casing 18 and the fitting fixing portions 43a, 43b that are
integrally connected to this sensor fixing portion 41, and the
temperature detection sensor 30 is fixed to the outer surface of
the sensor fixing portion 41, while the fitting fixing portions
43a, 43b are brazed to the outer surface of the casing 18.
[0060] Since the fitting fixing portions 43a, 43b are brazed to
positions on the outer surface of the casing 18 which correspond to
the outside of the brazed portions where one or a plurality of the
fins 26 are brazed to the casing 18, accordingly heat is
transferred from the heat exchange tubing 25 to the fitting fixing
portions 43a, 43b via the one or a plurality of fins 26 and the
casing 18, and the fitting fixing portions 43a, 43b are reliably
heated up to a temperature that reflects the temperature of the
heat exchange tubing 25 (i.e. to a temperature that is almost equal
to the temperature of the heat exchange tubing 25). And, since the
heat is transmitted from these fitting fixing portions 43a, 43b to
the sensor fixing portion 41, accordingly the sensor fixing portion
41 is also reliably heated up to a temperature that reflects the
temperature of the heat exchange tubing 25.
[0061] Since the predetermined clearance S is defined between the
sensor fixing portion 41 and the outer surface of the casing 18,
and the temperature detection sensor 30 is fixed to the outer
surface of the sensor fixing portion 41, accordingly, while the
state is maintained in which the temperature detection sensor is
not in contact with the outer surface of the casing 18, still the
temperature detection sensor 30 detects the temperature of the
sensor fixing portion 41, which reflects the temperature of the
heat exchange tubing 25. And it is possible to stabilize the
temperature detection performance of the temperature detection
sensor 30, since the heat transfer path that transfers heat from
the heat exchange tubing 25 to the sensor fixing portion 41 via the
one or a plurality of fins 26, the casing 18, and the fitting
fixing portions 43a, 43b remains the same and does not vary between
different ones of a plurality of examples of the same type of hot
water supply device.
[0062] The fixing fitting 40 is provided at a position on the outer
surface of the front wall 18a of the casing 18 that corresponds to
the straight pipe 27d, which is the portion in the lower heat
exchange tubing 25A of the heat exchange tubing 25 most toward the
downstream side in the flow direction of the hot water that
directly opposes the combustion space 13 of the burner section 3
from above, and that moreover corresponds to the combustion stage
#2, which is the combustion region whose frequency of usage in
combustion operation is the highest. In this manner, by attaching
the fixing fitting 40 in a position that corresponds to the heat
exchange tubing portion whose frequency of usage during combustion
operation is the highest and whose thermal load is accordingly the
highest, it is possible to detect a temperature that reflects the
temperature of the heat exchange tubing portion whose thermal load
is the highest.
[0063] Since clogging with scale can most easily occur in the heat
exchange tubing portion where the thermal load is highest, and
clogging of the fins can most easily occur in the vicinity of that
portion, accordingly it becomes possible to estimate the state of
accumulation of scale and/or soot at high accuracy using the
temperature detected by the temperature detection sensor 30
described above.
[0064] Since the fixing fitting 40 has the fitting fixing portions
43a, 43b on the left and right sides of the sensor fixing portion
41, accordingly it is possible to attach the fixing fitting 40 to
the casing 18 in a stable state. Moreover heat transference to the
sensor fixing portion 41 is excellent, since heat is conducted to
the sensor fixing portion 41 from the fitting fixing portions 43a,
43b on both sides.
[0065] Furthermore, since the locations where brazing is performed
on both the inner surface and the outer surface of the casing 18
are kept as small as possible by brazing only the fitting fixing
portions 43a, 43b of the fixing fitting 40 to the casing 18 without
its sensor fixing portion 41 being brazed to the casing 18,
accordingly it is possible to suppress thermal distortion of the
casing 18, and thereby it is possible to prevent deterioration of
the durability of the casing 18.
[0066] Next, examples in which the above embodiment is partially
varied will be explained.
[0067] 1) Since the protective cover 50 is not essential, it may be
omitted.
[0068] 2) The disclosed fixing fitting 40 has only been shown by
way of example; for a person skilled in the art, the present
invention could be implemented in formats in which various
modifications are included in the above embodiment, and it should
be understood that the present invention also includes such variant
embodiments.
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