Note: Descriptions are shown in the official language in which they were submitted.
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WARM AIR CONDENSING FURNACE WITH
IMPROVED DRAIN DISCHARGE
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a warm air furnace having
means for discharging drain which is a condensation of water
vapor in combustion gas.
Description of the Related Art
Conventionally, as a drain discharging means in a warm
air furnace, there is known a configuration formed so as to
reduce the combustion gas combusted at the combusting means
from leaking into a room. The first example has a drain pipe
provided at a midstream of an exhaust passage with a sealed
lower end, and a small-diameter hole formed at an upper side
surface of the drain pipe (refer to Japanese utility model
laid-open No. S57-0l0658). The second example has an orifice
provided inside the drain pipe (refer to Japanese utility model
laid-open No. S54-169937) . The third example makes the inner
diameter of a drain discharging pipe to be small diameter such
that an exhaust gas does not leak because a surface tension
of the drain (refer to Japanese utility model laid-open No.
S53-145752) .
In the drain discharging means of the warm air furnace
as is mentioned above, in the first example, drain is
accumulated in the drain pipe from the lower end of the drain
pipe to the height of the hole at the side surface of the drain
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pipe. Further, in the second and third examples, because of
the orifice provided in the drain pipe or because a membrane
is generated at the lower end of the drain discharging pipe
from the surface tension of the drain, drain is accumulated
in the drain pipe or the drain discharging pipe until a head
of water overcoming the surface tension of the drain is
generated.
That is, there is a problem that drain is accumulated
in the drain pipe of each of the conventional technique
mentioned above, so that corrosion may occur at the drainpipe
or the drain discharging pipe.
SUMMARY OF THE INVENTION
In view of such circumstances, an object of embodiments
of the present invention is to provide a warm air furnace
capable of reducing leaking of combusted gas combusted at a
combustor into a room, and to prevent drain from accumulating
in a drain pipe.
An embodiment of the present invention provides a warm
air furnace comprising: an air intaker which takes in outdoor
air; a combustor which is supplied with air taken in by the
air intaker together with combustion gas so as to combust the
same; an exhauster which exhausts combustion gas combusted
at the combustor outdoors; a thermal exchanger which is
provided at the exhauster and which transmits heat of the
combusting gas to indoor air; an air blower which blows indoor
air so as to have heat transmitted from the thermal exchanger;
and a drain discharger which discharges drain formed
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from condensation of water vapor inside the combustion gas
at the discharger; wherein the drain discharger is configured
in a pipe-like shape with one end connected to the discharger
and the other end opened into the warm air furnace below the
discharger, the other end of the drain discharger is formed
into a tubular portion with a membrane generated at a plane
orthogonal to an axis line by a surface tension of the drain,
and the leading end of the tubular portion is formed as an
opening having an area large enough such that the membrane
is not generated by the surface tension of the drain.
According to the present invention, the other end of the
pipe constituting the drain discharger is formed as the tubular
portion with membrane generated at the plane orthogonal to
the axis line by the surface tension of the drain. The
cross-section of such tubular portion is small enough to
suppress leaking of the combustion gas combusted at the
combustor into the room, so that it is possible to reduce leaking
of the combustion gas into the room.
On the other hand, the leading end of the tubular portion
is formed as the opening having the area large enough such
that the membrane is not generated by the surface tension of
the drain. Therefore, the drain flowing into the tubular
portion is discharged from the leading end of the tubular
portion, without generating the membrane at the leading end
of the tubular portion from the surface tension. By doing
so, it becomes possible to prevent drain from accumulating
in the drain pipe.
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In the present invention, the leading end of the
tubular portion is formed in an inclined manner, so that
membrane is not generated from the surface tension of the
drain.
Further, it is preferable that the tubular portion is
formed by crimping a side surface of the other end. By
doing so, it becomes possible to easily form the other end
of the drain discharger as the tubular portion with the
membrane generated at a plane orthogonal to the axis line
by the surface tension of the drain.
In one aspect, the invention provides a warm air
furnace comprising:
an air intaker which takes in outdoor air;
a combustor which is supplied with air taken in by
the air intaker together with fuel gas so as to combust
the same;
an exhauster which exhausts combustion gas caused by
combustion of the fuel gas at the combustor outdoors;
a thermal exchanger which is provided at the exhauster
and which is for transmitting heat of the combustion gas
combusted at the combustor to indoor air;
an air blower which blows indoor air so as to have
heat transmitted from the thermal exchanger; and
a drain discharger which discharges drain formed from
condensation of water vapor inside the combustion gas at
the exhauster;
wherein the drain discharger is a conduit with a first
end connected to the exhauster and a second end portion
opened into the warm air furnace below the exhauster,
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the second end portion of the drain discharger is
formed into a tubular portion with a membrane generated at
a plane orthogonal to an axis line of the tubular portion
by a surface tension of the drain,
a leading end of the tubular portion is formed as an
opening having an area large enough such that the membrane
is not generated by the surface tension of the drain, and
the tubular portion is formed by crimping a side surface
of the other end.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of an example of a warm air furnace
according to the present invention;
FIG. 2 is a side view of an example of the warm air furnace
according to the present invention;
FIG. 3 is a rear perspective view of an example of the
warm air furnace according to the present invention;
FIG. 4 is a view showing a drain pipe used in the warm
air furnace in FIG. 1 through FIG. 3;
FIG. 5 is a view of the drain pipe seen in a direction
of an arrow A in FIG. 4;
FIG. 6 is a view showing another example of the drain
pipe; and
FIG. 7 is a view showing the drain pipe from a direction
of an arrow B in FIG. 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
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In a warm air furnace 10 shown in FIG. 1, a combustion
blower 14 is attached to the right side of a flat,
horizontally-long casing 12 made of sheet-metal, and a
horizontal tubular combustion tube 16 is installed to the lower
portion thereof. A gas burner 18 as a combustor is provided
to the right end of the combustion tube 16, and is supplied
with combustion air from an air outlet of the combustion blower
14 and is provided with fuel gas from a fuel gas supply mechanism
20, so as to carry out combustion.
As shown in FIG. 2 and FIG. 3, the rear surface of the
casing 12 is connected with an outdoor air intake pipe 28 for
introducing outdoor air to the combustion blower 14, an air
duct 26, an exhaust outer pipe 40 for discharging combustion
gas combusted in the gas burner 18 outdoors, and a frame 22
for securing handling space of an exhaust duct 44. An air
inlet 24 of the combustion blower 14 is an inlet tube with
the leading end closed, which penetrates through the rear
surface of the casing 12 so as to protrude rearward. The side
surface of the air inlet 24 is connected with the air duct
26, and the air duct 26 is connected to the outdoor air intake
pipe 28 which is inserted into a hole (not shown) formed to
a wall of a room so as to connect outdoor and indoor inside
of the frame 22.
In the present embodiment, the combustion blower 14, the
outdoor air intake pipe 28, the air duct 26, the air inlet
24 and the combustion blower 14 constitutes an air intaker.
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A heat exchanger 30, which is a thermal exchanger for
conducting heat of the combustion gas to indoor air, is
installed horizontally on the upper side of the combustion
tube 16 inside the casing 12. The left end of the combustion
tube 16 and the left end of the heat exchanger 30 are connected
by a connecting tube 32 with a rectangular cross-section. An
exhaust tube 34 is attached between the heat exchanger 30 and
the combustion tube 16 in parallel thereto. The right end
of the heat exchanger 30 and the right end of the exhaust tube
34 are connected by a connecting tube 36 with a rectangular
cross-section.
A leading end 38 of the exhaust tube 34 is bent 90 towards
the rear surface side. The exhaust tube 34 penetrates through
a backboard 12a, extends rearward and becomes an exhaust outlet
of the gas burner 18. Further, the leading end 38 is connected
to the exhaust outer pipe 40 which is installed inside the
outdoor air intake pipe 28 coaxially thereto via the exhaust
duct 44, inside the frame 22.
In the present embodiment, the connecting tube 32, the
connecting tube 36, the exhaust outer pipe 40 and the exhaust
duct 44 constitutes the exhauster.
An elongated cylindrical warm air blow fan 46, which is
a blower, is installed horizontally at the upper portion of
the casing 12. The warm air blow fan 46 blows out the indoor
air taken in from an indoor air inlet 48 (refer to FIG. 3)
formed at the upper portion of the back board 12a of the casing
12 frontward from a warm air outlet 50 (refer to FIG. 2) formed
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at the lower portion of a front board 12b of the casing 12.
The indoor air flows around the heat exchanger 30, the exhaust
tube 34, and the combustion tube 16, is heated to a high
temperature from heat exchanging therewith, and is blown out
frontward from the warm air outlet 50.
Ahumidifying water dish 52 is installed on a casingbottom
board 12c below the combustion tube 16 inside the casing 12,
so as to be pulled out from the front side thereof.
A concave 38a expanding downward (refer to FIG. 2) is
formed to the lower surface of the leading end 38 of the exhaust
tube 34, so as to form an accumulating region of the drain.
An upper end of a drain pipe 54 is vertically connected to
the concave 38a. The lower end of the drain pipe 54 faces
downward, and is opened so as to drop the drain into the
humidifying water dish 52.
As is shown in FIG. 4, the drain pipe 54 is comprised
of an upper end portion 54a extending from the upper end for
a predetermined distance downward, an arc portion 54c extending
from the upper end portion 54a downward in an arcuate shape
along the combustion tube 16, and a lower end portion 54b
extending along a tangent line of the arc portion 54c for a
predetermined distance.
The lower end portion 54b of the drain pipe 54 is formed
as a tubular portion with a membrane generated at a plane
orthogonal to an axis line 54d by a surface tension of the
drain. Therefore, the cross-sectional area of the tubular
portion is small enough to suppress leaking of the combustion
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gas combusted at the combustor into the room, so that it is
possible to decrease the leaking of the combustion gas into
the room.
The tubular portion constituting the lower end portion
54b of the drain pipe 54 is formed by crimping the side surface
thereof in parallel to the axis line 54d, so that it has a
crimped line 54g.
On the other hand, the lower end of the tubular portion
as is explained above is formed as an opening having an area
large enough such that the membrane is not generated by the
surface tension of the drain. In the present embodiment, the
lower end 54e of the tubular portion is formed in an inclined
manner with respect to the axis line 54d of the tubular portion.
By doing so, as is shown in FIG. 5, the area of an inclined
opening 54f at the lower end 54e of the tubular portion is
made larger than the opening area of the plane orthogonal to
the axis line 54d of the tubular portion, and becomes large
enough such that the membrane is not generated by the surface
tension of the drain.
The opening formed at the lower end of the tubular portion
is not limited to the case where the lower end thereof is formed
in the inclined manner, and may be formed to have an area large
enough such that the membrane is not generated from the surface
tension of the drain.
In the present embodiment, as is explained above, the
lower end portion 54b constituting the drain pipe 54 is formed
as a tubular portion with the membrane generated at a plane
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orthogonal to the axis line 54d by the surface tension of the
drain. As such, the opening area of the lower end portion
54b is small enough to suppress leaking of the combustion gas
combusted at the gas burner 18 into the room, but the lower
end 54e of the tubular portion is formed in the inclined manner
with respect to the axis line 54d, and the opening area thereof
is large enough such that the membrane is not generated by
the surface tension of the drain. Therefore, the drain flowing
into the tubular portion is discharged without generating the
membrane from the surface tension. By doing so, it becomes
possible to prevent drain from accumulating in the drain pipe
54.
Further, the tubular portion is formed by crimping the
side surface of the lower end portion 54b of the drain pipe
54, so that the lower end portion 54b may be formed easily
as the tubular portion with the membrane generated at a plane
orthogonal to the axis line 54d by the surface tension of the
drain.
The lower end portion 54b of the drain pipe 54 of the
present embodiment is a straight pipe having uniform inner
diameter. However, as is shown in FIG. 6 and FIG. 7, a lower
end portion 56b of a similar drain pipe 56 may be formed as
a tubular portion in which the inner diameter thereof decreases
toward the lower end, by forming the crimping line 56g by
crimping the side surface of the lower end portion 56b of the
drain pipe 56 so that it becomes angled with respect to the
axis line 56d. An opening 56f of a lower end portion 56e is
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formed so that the area thereof is smaller than the opening
54f in FIG. 5. Therefore, it becomes possible to further
suppress leaking of the combustion gas into the room.
