BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to an outdoor unit of an air conditioning apparatus
and, more particularly, to improvement of a drain water discharge structure.
2. Description of the Related Art
[0002] When a heating mode of operation is performed in an outdoor unit of a separate type
air conditioning apparatus, a heat exchanger is deprived of heat by a turning fan.
At this time, the heat exchanger condenses the water vapor in the air, causing its
surface to be frosted. As time progresses, such frost develops and finally impedes
air flow through the heat exchanger and prevents heat from moving. This inhibits heat
exchange and heating in a room. To avoid this, the outdoor unit generally performs
defrosting operation for a predetermined period of time, thereby melting the frost
for resumption of heat exchange. After that, heating and defrosting modes of operation
are repeated.
[0003] During the defrosting mode of operation, the frost on the external surface of the
heat exchanger melts and drops down as drain water droplets. Conventional outdoor
units have a drain water discharge conduit provided on its bottom plate beneath the
heat exchanger for discharging the drain water. Such a drain water discharge conduit
has a horizontal section formed at a lowest portion thereof, the horizontal section
having a drain hole through which the drain water is discharged (for example, see
Japanese Unexamined Patent Application Publication No.
2005-188837 (Fig. 1) and Japanese Unexamined Patent Application Publication No.
2005-213779 (Figs. 6 and 8)).
SUMMARY OF THE INVENTION
[0004] Drain water droplets from such an outdoor unit drop onto the discharge conduit into
the drain hole through which the drain water is discharged to the outside. However,
in a cold area the drain water may freeze before reaching the drain hole at low ambient
temperatures. In particular, the drain water may freeze in the horizontal section
around the drain hole, blocking the drain hole or the drain water discharge conduit.
If this happens, not only does the frozen drain water inhibit the discharge of the
drain water to the outside, but also may cause the horizontal section to further expand
to such a degree that the flow of the drain water is degraded, which causes a great
amount of water remaining inside the unit to more and more tend to freeze. In addition,
each time heating and defrosting modes of operation are repeated, the frozen drain
water further develops, causing the heat exchanger to malfunction and damaging the
outdoor unit.
[0005] The present invention has been achieved to solve the above-described problems. A
first object of the present invention is to provide an outdoor unit which ensures
that drain water is discharged on a rapid manner, and a drain hole is prevented from
freezing so that the drain water can be discharged even in a cold area.
[0006] A second object of the present invention is to provide an outdoor unit which has
a bottom plate having a shallow depth, thereby improving the workability as well as
strength.
[0007] An outdoor unit of an air conditioning apparatus according to the present invention
includes a bottom plate on which at least a heat exchanger is placed, a conduit forming
wall formed upright on the bottom plate along the heat exchanger, and a water conduit
formed by the conduit forming wall which has a drain hole and a downwardly tilted
surface continuous with the drain hole.
[0008] According to an outdoor unit of an air conditioning apparatus of the present invention,
a bottom plate has a conduit forming wall formed upright thereon along the heat exchanger,
and a water conduit formed by the conduit forming wall has a drain hole and a downwardly
tilted surface continuous with the drain hole, which allows drain water droplets to
flow to the drain hole without reducing its flow rate. This ensures that drain water
passages concentrate and that drain water reaches the drain hole without freezing,
thereby preventing the blockage of the drain hole or the water conduit. Also, the
conduit forming wall formed upright on the bottom plate along the heat exchanger serves
as a reinforcement rib of the bottom plate. Accordingly, workability as well as strength
can be improved without deepening the bottom plate in the direction of the depth.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009]
Fig. 1 is a perspective view showing a bottom plate of an outdoor unit of an air conditioning
apparatus according to an embodiment of the present invention;
Fig. 2 is a perspective view showing the bottom plate of an outdoor unit of an air
conditioning apparatus according to an embodiment of the present invention, on which
a heat exchanger and a compressor are mounted;
Fig. 3 is a top view showing the bottom plate on which a blower and a partition in
addition to those as shown in Fig. 2 are mounted; and
Fig. 4 is a perspective view showing the entire outdoor unit of an air conditioning
apparatus according to an embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] The present invention is described based on an embodiment as shown in the figures.
Fig. 1 is a perspective view showing a bottom plate of an outdoor unit of an air conditioning
apparatus according to an embodiment of the present invention. Fig. 2 is a perspective
view showing the bottom plate on which a heat exchanger and a compressor are mounted.
Fig. 3 is a top view showing the bottom plate on which a blower and a partition in
addition to those as shown in Fig. 2 are mounted. Fig. 4 is a perspective view showing
the appearance of the entire outdoor unit.
[0011] An outdoor unit 100 of an air conditioning apparatus according to this embodiment
includes a heat exchanger 2, a compressor 3, a blower 4, and a partition 5 mounted
on a steel bottom plate 1 in the form of a rectangular solid, as shown in Figs. 1
to 4. These components are enclosed by an enclosure constructed of a peripheral wall
6 and a top plate 7.
[0012] The bottom plate 1 includes a frame 1a (hereinafter referred to as "peripheral frame")
surrounding the bottom plate 1 and a conduit forming wall 1c formed upright along
the heat exchanger 2. A water conduit 1d is formed by partitioning with the conduit
forming wall 1c and the peripheral frame 1a. The conduit forming wall 1c prevents
drain water from flowing into below the heat exchanger 2 or out of the water conduit.1d.
The water conduit 1d has a normally open drain hole 1b for discharging drain water
to the outside and a downwardly tilted surface 1e (equal to the bottom face of the
water conduit) continuous with the drain hole 1b. The bottom plate 1 is also formed
as a whole to be downwardly tilted toward the drain hole 1b.
[0013] The water conduit 1d has a plurality of heat exchanger mounting bases 1f formed at
an edge and a corner thereof. The heat exchanger 2 is placed and secured on the mounting
bases 1f. The mounting bases 1f are formed to have a height smaller than that of the
adjacent conduit forming wall 1c or the peripheral frame 1a. The bottom plate 1 has
the peripheral frame 1a, the conduit forming wall 1c, the tilted surface 1e, and the
heat exchanger mounting bases 1f integrally formed thereon by press working.
[0014] When the air conditioning apparatus according to this embodiment performs heating
operation, the surface of the heat exchanger 2 in the outdoor unit 100 becomes frosted.
Defrosting mode of operation is performed for a certain period of time to melt the
frost on the surface. Water generated by such defrosting mode of operation drops as
drain water onto the downwardly tilted surface 1e continuous with the drain hole 1b
in the water conduit 1d on the bottom plate 1 and is guided to the drain hole 1b.
Accordingly, such drain water flows at a high rate only below the heat exchanger 2,
while concentrating. This prevents the drain water from freezing in the water conduit
1d before it reaches the drain hole 1b even at low ambient temperatures in a cold
area, thereby securely discharging the drain water.
[0015] The mounting bases 1f formed to have a height smaller than that of the adjacent conduit
forming wall 1c or the peripheral frame 1a ensures that the drain water downwardly
flowing on the external surface of the heat exchanger 2 drops onto the water conduit
1d through the lower end of the heat exchanger 2.
[0016] As described above, the outdoor unit of an air conditioning apparatus according to
this embodiment includes the downwardly tilted surface 1e continuous with the drain
hole 1b and the conduit forming wall 1c formed upright along the heat exchanger 2
so as to prevent the drain water from flowing other than below the heat exchanger
2, which allows drain water passages to concentrate, raises the drain water flow rate,
and prevents the drain water from freezing before it reaches the drain hole 1b, thereby
securing that the drain water is discharged to the outside. This prevents the drain
hole 1b and the water conduit 1d from being blocked.
[0017] The conduit forming wall 1c formed to have an upright structure also serves as a
reinforcement rib of the bottom plate 1. This improves workability of steel sheet
working (sheet metal working) as well as the strength of the bottom plate 1 without
deepening the bottom plate 1 in the direction of the depth.