U.S. patent application number 12/624567 was filed with the patent office on 2010-06-03 for air supply fan device.
This patent application is currently assigned to RINNAI CORPORATION. Invention is credited to Masayoshi Takayama.
Application Number | 20100135829 12/624567 |
Document ID | / |
Family ID | 41720610 |
Filed Date | 2010-06-03 |
United States Patent
Application |
20100135829 |
Kind Code |
A1 |
Takayama; Masayoshi |
June 3, 2010 |
AIR SUPPLY FAN DEVICE
Abstract
An air supply fan device including: a fan casing disposed
continuously to a combustion chamber containing a gas burner
therein; an air supply fan contained inside of the fan casing, for
supplying burning air to the gas burner; and a motor disposed
outside of the fan casing, for rotating the air supply fan. The air
supply fan device comprising: a ventilation hole formed by opening
a fan casing constituting wall around a motor rotary shaft of the
motor connected to the air supply fan; and a diaphragm valve body
which is fixed to the ventilation hole and has a through hole,
through which the motor rotary shaft is inserted, opened at the
center thereof. The valve body being formed into a shape such that
a gap is defined between the through hole and the motor rotary
shaft when the inner pressure inside of the fan casing is negative
during the rotation of the air supply fan while the gap is closed
in tight contact of the peripheral edge of the through hole with
the motor rotary shaft when the inner pressure inside of the
combustion chamber or the fan casing is positive.
Inventors: |
Takayama; Masayoshi;
(Nagoya-shi, JP) |
Correspondence
Address: |
TUROCY & WATSON, LLP
127 Public Square, 57th Floor, Key Tower
CLEVELAND
OH
44114
US
|
Assignee: |
RINNAI CORPORATION
Nagoya-shi
JP
|
Family ID: |
41720610 |
Appl. No.: |
12/624567 |
Filed: |
November 24, 2009 |
Current U.S.
Class: |
417/366 |
Current CPC
Class: |
F23L 5/02 20130101; F23N
2233/06 20200101; F23N 3/08 20130101 |
Class at
Publication: |
417/366 |
International
Class: |
F04D 29/58 20060101
F04D029/58 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 28, 2008 |
JP |
2008-304785 |
Claims
1. An air supply fan device including: a fan casing disposed
continuously to a combustion chamber containing a gas burner
therein; an air supply fan contained inside of the fan casing, for
supplying burning air to the gas burner; and a motor disposed
outside of the fan casing, for rotating the air supply fan, the air
supply fan device comprising: a ventilation hole formed by opening
a fan casing constituting wall around a motor rotary shaft of the
motor connected to the air supply fan; and a diaphragm valve body
which is fixed to the ventilation hole and has a through hole,
through which the motor rotary shaft is inserted, opened at the
center thereof; the valve body being formed into a shape such that
a gap is defined between the through hole and the motor rotary
shaft when the inner pressure inside of the fan casing is negative
during the rotation of the air supply fan while the gap is closed
in tight contact of the peripheral edge of the through hole with
the motor rotary shaft when the inner pressure inside of the
combustion chamber or the fan casing is positive.
2. The air supply fan device according to claim 1, wherein the
valve body is made of a rubber sheet, and further, is formed into a
projecting or recessed shape in such a manner as to enlarge a
pressure receiving area of a pressure receiving portion which
receives an air pressure inside of the fan casing.
3. The air supply fan device according to claim 1, wherein the
inner diameter of the through hole is greater than the outer
diameter of the motor rotary shaft, so as to define a clearance
therebetween in the valve body when the inside and outside
pressures of the fan casing are equal to each other.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an air supply fan device in
a combustion apparatus and, more particularly, to an air supply fan
device in which air-tightness is enhanced such that combustion
exhaust gas staying inside of a combustion chamber cannot leak from
the air supply fan device.
[0003] 2. Description of the Related Art
[0004] A combustion apparatus for a water heater may be provided
with an air supply fan device including an air supply fan in a
combustion chamber containing a gas burner therein. In such an air
supply fan device, when the temperature of air to be supplied into
the combustion chamber is increased, the temperature of a motor for
rotating the air supply fan device or a motor rotary shaft also is
increased, thereby often raising a fear of a trouble with the
rotation of the motor. In, for example, a combustion apparatus of
an FF type (forced draft balanced flue type) duplex supply/exhaust
system in which a supply channel, through which outside air is
supplied into a combustion chamber, and an exhaust channel, through
which combustion exhaust gas staying in the combustion chamber is
exhausted to the outside, are constituted of a single
supply/exhaust cylinder, the outside air to be supplied is heated
by the combustion exhaust gas, and therefore, the temperature of
the motor rotary shaft is liable to be increased.
[0005] In view of the above, there has been conventionally proposed
an air supply fan device which takes measures against such an
increase in temperature of a motor rotary shaft. Referring to FIGS.
6 and 7, a motor cooling ventilation hole 49 is formed in a fan
casing constituting wall 411 around a motor rotary shaft 43
connected to an air supply fan device 41 inside of a fan casing
410, and further, a self-cooled fan 44, which projects by
resiliency of a spring 47 during stoppage of rotation of a motor 42
so as to close the ventilation hole 49 (FIG. 6) whereas retreats
against the resiliency of the spring 47 during the rotation of the
motor 42 so as to open the ventilation hole 49 (FIG. 7), is
disposed in the motor rotary shaft 43 outside of the fan casing 410
in an air supply fan device (the related art) disclosed in Japanese
Patent Laid-open No. H05-52321. In FIGS. 6 and 7, reference numeral
45 designates a stopper, and further, 44b denotes a base for the
self-cooled fan 44.
[0006] With this configuration, when the self-cooled fan 44 is
rotated according to the rotation of the motor 42, an air passage
is defined from the ventilation hole 49 to the fan casing 410 (FIG.
7), so that the motor rotary shaft 43 or the motor 42 is cooled. In
contrast, when the rotation of the motor 42 is stopped, the
ventilation hole 49 is closed with the base 44b of the self-cooled
fan 44 (FIG. 6), so that combustion exhaust gas staying inside of a
combustion chamber can be prevented from flowing out (back) through
the ventilation hole 49, thus suppressing a leakage quantity of the
combustion exhaust gas from the combustion chamber.
[0007] However, in the related art, the outer peripheral surface of
the motor rotary shaft 43 and the inner circumferential edge of the
ventilation hole 49 are not fully closed since there is a clearance
k therebetween when the motor 42 is stopped from being rotated (see
FIG. 6). In addition, although the self-cooled fan 44 is urged by
the spring 47, if an inner pressure inside of the combustion
chamber is increased, the self-cooled fan 44 may retreat outward of
the fan casing 410 (i.e., toward the motor 42) against the
resiliency of the spring 47. As a consequence, when the inner
pressure inside of the combustion chamber or the fan casing 410
becomes positive by, for example, outside air blown into a
supply/exhaust cylinder due to a blast, the clearance at the
ventilation hole 49 is enlarged, so that the combustion exhaust gas
remaining inside of the combustion chamber flows back, to flow out
through the ventilation hole 49. In this manner, with the
conventional structure, it is difficult to suppress the leakage of
the combustion exhaust gas from the combustion chamber against the
positive pressure applied to the combustion chamber and the fan
casing.
SUMMARY OF THE INVENTION
[0008] The present invention has been accomplished to solve the
above-described problems experienced in the related art. Therefore,
an object of the present invention is to provide an air supply fan
device, in which a motor rotary shaft or a motor can be securely
cooled, and further, combustion exhaust gas can be prevented from
leaking through a ventilation hole at the time of application of a
positive pressure to a combustion chamber or a fan casing.
[0009] According to the present invention, there is provided An air
supply fan device including: a fan casing disposed continuously to
a combustion chamber containing a gas burner therein; an air supply
fan contained inside of the fan casing, for supplying burning air
to the as burner; and a motor disposed outside of the fan casing,
for rotating the air supply fan, the air supply fan device
comprising:
[0010] a ventilation hole formed by opening a fan casing
constituting wall around a motor rotary shaft of the motor
connected to the air supply fan; and
[0011] a diaphragm valve body which is fixed to the ventilation
hole and has a through hole, through which the motor rotary shaft
is inserted, opened at the center thereof;
[0012] the valve body being formed into a shape such that a gap is
defined between the through hole and the motor rotary shaft when
the inner pressure inside of the fan casing is negative during the
rotation of the air supply fan while the gap is closed in tight
contact of the peripheral edge of the through hole with the motor
rotary shaft when the inner pressure inside of the combustion
chamber or the fan casing is positive.
[0013] With the above-described configuration, when the air supply
fan is rotated and the pressure inside of the fan casing becomes
negative, the valve body is deformed in such a manner as to be
sucked inside of the fan casing, thereby defining the clearance
between the through hole and the motor rotary shaft. And then, air
flow is formed to flow into the fan casing through the through
hole, thus cooling the motor rotary shaft or the motor.
[0014] In contrast, when the pressure inside of the combustion
chamber or the fan casing becomes positive during the stoppage of
the rotation of the air supply fan, the valve body is deformed in
such a manner as to be pushed outward of the fan casing, so that
the peripheral edge of the through hole is brought into tight
contact with the motor rotary shaft, thus closing the clearance
defined between the through hole and the motor rotary shaft. Thus,
it is possible to prevent combustion exhaust gas staying inside of
the combustion chamber from flowing, back outward through the
ventilation hole, and further, to prevent the combustion exhaust
gas staying inside of the combustion chamber from leaking.
[0015] Preferably, the valve body is made of a rubber sheet, and
further, is formed into a projecting or recessed shape in such a
manner as to enlarge a pressure receiving area of a pressure
receiving portion which receives an air pressure inside of the fan
casing.
[0016] In this way, a pressure receiving portion is sensitive to a
change in air pressure inside of the fan casing, so that the valve
body is quickly deformed. As a consequence, when the pressure
inside of the fan casing becomes negative, the clearance is quickly
defined, and therefore, the motor rotary shaft can be quickly
cooled. In contrast, when the pressure inside of the fan casing
becomes positive, the clearance is quickly closed, and therefore,
the combustion exhaust gas hardly leaks.
[0017] Additionally, the valve body is excellent in tightness of
the peripheral edge of the through hole with respect to the motor
rotary shaft owing to the property of a rubber sheet, thereby
exhibiting high sealability, so as to more securely prevent the
combustion exhaust gas from leaking through the ventilation
hole.
[0018] Preferably, the inner diameter of the through hole is
greater than the outer diameter of the motor rotary shaft, so as to
define a clearance therebetween in the valve body when the inside
and outside pressures of the fan casing are equal to each
other.
[0019] Therefore, the motor rotary shaft cannot be brought into
contact with the through hole of the valve body when the motor is
started to be rotated. As a consequence, the valve body cannot be
broken due to the rotation of the motor, or an extra load cannot be
exerted on the rotation of the motor. Furthermore, the sealability
of the valve body can be held for a long period of time when the
pressure of the combustion chamber is positive.
[0020] As described above, in the air supply fan device according
to the present invention, the motor rotary shaft or the motor can
be securely cooled, and further, the combustion exhaust gas can be
securely prevented from leaking through the ventilation hole when
the positive pressure is applied to the combustion chamber or the
fan casing.
[0021] Other objects, features and advantages of the present
invention will become more fully understood from the detailed
description given hereinbelow and the accompanying drawings which
are given by way of illustration only, and thus are not to be
considered as limiting the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a view schematically showing the configuration of
a water heater, to which an air supply fan device in a preferred
embodiment is applied;
[0023] FIG. 2 is a cross-sectional view showing the entire
configuration of the air supply fan device in the preferred
embodiment;
[0024] FIG. 3 is a perspective view showing a valve body to be
fixed to the air supply fan device;
[0025] FIG. 4 is a cross-sectional view showing the valve body when
a pressure inside of a fan casing becomes negative when an air
supply fan is rotated in the air supply fan device;
[0026] FIG. 5 is a cross-sectional view showing the valve body when
the pressure inside of the fan casing becomes positive when the
rotation of the air supply fan is stopped in the air supply fan
device;
[0027] FIG. 6 is a cross-sectional view showing a conventional air
supply fan device when rotation of a motor is stopped; and
[0028] FIG. 7 is a cross-sectional view showing the conventional
air supply fan device when the motor is rotated.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0029] A detailed description will be given below of a preferred
embodiment according to the present invention with reference to the
attached drawings.
[0030] FIG. 1 is a view showing the entire configuration of a
combustion apparatus (i.e., a water heater), to which an air supply
fan device in a preferred embodiment according to the present
invention is applied; FIG. 2 is a cross-sectional view showing the
entire configuration of the air supply fan device; and FIG. 3 is a
perspective view showing a valve body to be fixed to the air supply
fan device.
[0031] A water heater 1 serving as a combustion apparatus
illustrated in FIG. 1 is designed for an FF type (forced draft
balanced flue type) duplex supply/exhaust system including a
supply/exhaust manifold 11 provided with a duplex pipe. Inside of
an apparatus body 10 of the water heater 1, there is provided a
combustion chamber 14 containing a gas burner 15 and a heat
exchanger 16 therein. An air supply fan device 2 is continuously
disposed under the combustion chamber 14. The supply/exhaust
manifold 11 is constituted of an inner pipe in a duplex pipe, that
is, an exhaust cylinder 12 for allowing combustion exhaust gas to
be exhausted from the combustion chamber 14 and an outer pipe, that
is, a supply pipe 13 for taking air from the outside. The open end
of the supply/exhaust manifold 11 is opened to the outside through
a wall of a room, at which the water heater 1 is installed. The
exhaust pipe 12 is connected to the upper portion of the combustion
chamber 14, and constitutes an exhaust channel for exhausting the
combustion exhaust gas from the combustion chamber 14 to the
outside. The supply pipe 13 extends downward inside of the
apparatus body 10, and the distal end thereof is continuously
disposed in the air supply fan device 2 in an air-tight manner,
thus constituting a supply channel for supplying outside air into
the combustion chamber 14. Here, the combustion chamber 14 and the
supply/exhaust manifold 11 are connected to each other in an
air-tight manner.
[0032] As shown in FIG. 2, the air supply fan device 2 includes: a
fan casing 20 continuously disposed in the combustion chamber 14 in
an air-tight manner; an air supply fan 21, or a sirocco fan housed
inside of the fan casing 20, for supplying burning air to the gas
burner 15; and a motor 22 disposed outside of the fan casing 20,
for rotating the air supply fan 21. Onto one constituting wall 24a
sideways of the fan casing 20 is disposed the air supply cylinder
13 in an air-tight manner, and further, a fixing plate 25 for the
motor 22 is securely attached to the outer surface of a
constituting wall 24b opposite to the constituting wall 24a. The
motor 22 is fixed to the fixing plate 25. A circular ventilation
hole 26 is formed on the constituting wall 24b of the fan casing
20, onto which the motor 22 is fixed. A motor rotary shaft 23 for
the motor 22 penetrates through the ventilation hole 26, and is
connected to the air supply fan 21 housed inside of the fan casing
20. The inner diameter of the ventilation hole 26 is greater than
the outer diameter of the motor rotary shaft 23. Therefore, an
annular opening 27 is defined around the motor rotary shaft 23. A
circular diaphragm valve body 3 is disposed around and in the
ventilation hole 26.
[0033] As shown in FIG. 3, the valve body 3 is made of a circular
rubber sheet having an outer diameter greater than that of the
ventilation hole 26, and includes a through hole 31 opened at the
center in such a manner as to allow the motor rotary shaft 23 to be
inserted therethrough and a flange 32 extending outwards in such a
manner as to be fixed onto the constituting wall 24b of the fan
casing 20. Incidentally, although the flange 32 is air-tightly
attached to the inner surface of the constituting wall 24b of the
fan casing 20 in the valve body 3 shown in FIG. 2, it may be
air-tightly attached to the outer surface of the constituting wall
24b.
[0034] Referring to FIG. 2, a peripheral edge 31a of the through
hole 31 of the valve body 3 is formed in such a manner as to
protrude toward the air supply fan 21 in a cylindrical shape. The
inner diameter of the through hole 31 is slightly greater than the
outer diameter of the motor rotary shaft 23, and therefore, a
clearance 35 is defined therebetween. Therefore, the motor rotary
shaft 23 cannot be brought into contact with the through hole 31 at
the time of start of rotation of the motor 22 (pressure is equal
inside and outside of the fan casing 20, see FIG. 2). Thus, it is
possible to prevent the motor rotary shaft 23 from sliding in
contact with the through hole 31 of the valve body 3 at the time of
the start of the rotation of the motor 22.
[0035] A region from the through hole 31 to the flange 32 in the
valve body 3 serves as a pressure receiving portion 33 for
receiving an air pressure inside of the fan casing 20. The pressure
receiving portion 33 is expanded (projects) inward of the fan
casing 20. In this manner, a greater pressure receiving area
receiving the air pressure inside of the fan casing 20 can be
provided, so that the valve body 3 can be quickly moved according
to a change in air pressure inside of the fan casing 20. Here, the
pressure receiving portion 33 may be expanded (recessed) outward of
the fan casing 20.
[0036] With the air supply fan device 2 having the above-described
configuration, the gas burner 15 in the combustion chamber 14 burns
the air, and then, the air supply fan 21 is rotated, so that the
outside air is supplied as the burning air from the air supply
cylinder 13 into the combustion chamber 14 through the fan casing
20, thereby making the inner pressure of the fan casing 20
negative. Thereafter, as shown in FIG. 4, the valve body 3 disposed
in the ventilation hole 26 is deformed in such a manner as to be
sucked inward of the fan casing 20, so that the diameter of the
through hole 31 of the valve body 3 is increased. Thus, a gap 34 is
defined between the through hole 31 of the valve body 3 and the
motor rotary shaft 23. And then, the air around the motor rotary
shaft 23 is sucked into the fan casing 20 through the ventilation
hole 26 and the through hole 31 of the valve body 3. In this
manner, the air around the motor 22 outside of the fan casing 20
flows between the motor 22 and the fan casing 20, as indicated by
an arrow A in FIG. 4. That is to say, air flow A is formed to be
sucked into the fan casing 20 through the ventilation hole 26 and
the through hole 31 of the valve body 3. Thus, the air flow A can
effectively cool the motor rotary shaft 23 and the motor 22.
[0037] In contrast, if the inner pressure inside of the combustion
chamber 14 or fan casing 20 becomes positive by, for example, the
outside air such as a blast blowing into the supply/exhaust
manifold 11 during the stoppage of the rotation of the air supply
fan 21, the valve body 3 is deformed in such a manner as to be
pushed outside of the fan casing 20 by air flow B from the inside
of the fan casing 20 toward the ventilation hole 26, as shown in
FIG. 5. And then, the diameter of the peripheral edge 31a of the
through hole 31 projecting toward the air supply fan 21 in a
cylindrical shape in the valve body 3 is reduced, the gap 34
between the through hole 31 and the motor rotary shaft 23 is closed
in tight contact with the motor rotary shaft 23. As a consequence,
even if the combustion exhaust gas staying inside of the combustion
chamber 14 reversely flows into the fan casing 20, the combustion
exhaust gas can be prevented from flowing outward through the
ventilation hole 26, thus securely preventing the combustion
exhaust gas staying inside of the combustion chamber 14 from
leaking from the air supply fan device 2. In addition, the valve
body 3 can exhibit a high sealability owing to excellent
air-tightness of the peripheral edge 31a of the through hole 31
with respect to the motor rotary shaft 23 due to the properties of
the rubber sheet, thus further securely preventing the combustion
exhaust gas from leaking through the ventilation hole 26. The
outside pressure of the air supply fan device 2 becomes negative by
ventilating the room, at which the water heater 1 is installed, so
that even if the air pressure inside of the combustion chamber 14
or the fan casing 20 becomes high (substantially, the pressure
inside of the combustion chamber 14 or the fan casing 20 is
positive), the valve body 3 is deformed to close the gap 34 defined
between the through hole 31 and the motor rotary shaft 23, as shown
in FIG. 5.
[0038] As described above, with the air supply fan device 2 in the
present embodiment, the motor rotary shaft 23 or the motor 22 can
be effectively cooled when the air supply fan 21 is rotated. During
the stoppage of the rotation of the air supply fan 21, the
combustion exhaust gas remaining inside of the combustion chamber
14 can be securely prevented from leaking through the ventilation
hole 26 of the fan casing 20 even if the positive pressure is
applied inside of the combustion chamber 14 or the fan casing
20.
[0039] When the inside and outside pressures of the fan casing 20
are equal to each other, the inner diameter of the through hole 31
of the valve body 3 is greater than the outer diameter of the motor
rotary shaft 23, thus defining the clearance 35. As a consequence,
when the motor 22 is started to be rotated, the motor rotary shaft
23 cannot be brought into contact with the through hole 31 of the
valve body 3. Thus, it is possible to prevent the valve body 3 from
being damaged by the rotation of the motor 22 or an extra load from
being exerted on the rotation of the motor 22, and further, to
maintain the sealability of the valve body 3 for a long period of
time when the inside pressure of the combustion chamber 14 is
positive.
[0040] The valve body 3 is made of the rubber sheet, and further,
the pressure receiving portion 33 is formed into a projecting or
recessed shape so as to enlarge the pressure receiving area, at
which the air pressure inside of the fan casing 20 is received.
Consequently, the valve body 3 sensitively reacts against the
change in air pressure inside of the fan casing 20, to be deformed
quickly. Therefore, when the inner pressure inside of the fan
casing 20 becomes negative, the gap 34 is quickly defined, thereby
quickly cooling the motor rotary shaft 23 or the like. In contrast,
when the inner pressure inside of the fan casing 20 becomes
positive, the gap 34 is quickly closed, thereby virtually
preventing any leakage of the combustion exhaust gas.
[0041] Additionally, unlike the related art shown in FIGS. 6 and 7
in which the self-cooled fan is provided in the motor rotary shaft
23, the air supply fan device 2 produces the following advantages.
That is, the motor 22 can be fixed near the fan casing 20, thus
configuring the compact air supply fan device 2; there is no
problem of occurrence of noise in association with the rotation of
the self-cooled fan; no extra load for rotating the self-cooled fan
is exerted on the motor 22; and cost need not be increased since no
self-cooled fan is provided.
[0042] The present invention is not limited to the above-described
embodiment, but various modifications can be embodied within the
scope of the present invention.
[0043] For example, the outline shape of the valve body 3 or the
shape of the ventilation hole 26 is not limited to a circle, but
may be a polygon such as a square.
[0044] In addition, the air supply fan device 2 according to the
present invention is not limited to the water heater, but may be
applied to a combustion apparatus for a heater or appliances other
than the combustion apparatus of the FF type (forced draft balanced
flue type) duplex supply/exhaust system.
[0045] The present application claims a priority based on a
Japanese Patent Application No. 2008-304785 filed on Nov. 28, 2008,
the content of which is hereby incorporated by reference in its
entirely.
* * * * *