U.S. patent application number 13/980588 was filed with the patent office on 2013-11-14 for heat exchanger and air conditioner.
This patent application is currently assigned to DAIKIN INDUSTRIES, LTD.. The applicant listed for this patent is Masanori Jindou, Toshimitsu Kamada, Yoshio Oritani, Shun Yoshioka. Invention is credited to Masanori Jindou, Toshimitsu Kamada, Yoshio Oritani, Shun Yoshioka.
Application Number | 20130299153 13/980588 |
Document ID | / |
Family ID | 46515547 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130299153 |
Kind Code |
A1 |
Jindou; Masanori ; et
al. |
November 14, 2013 |
HEAT EXCHANGER AND AIR CONDITIONER
Abstract
Each of a plurality of heat-transfer portions has a plurality of
protrusions which are protruded toward an air passage and extend in
a direction intersecting with an airflow direction. The protrusions
are arranged in the airflow direction.
Inventors: |
Jindou; Masanori; (Osaka,
JP) ; Oritani; Yoshio; (Osaka, JP) ; Yoshioka;
Shun; (Osaka, JP) ; Kamada; Toshimitsu;
(Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Jindou; Masanori
Oritani; Yoshio
Yoshioka; Shun
Kamada; Toshimitsu |
Osaka
Osaka
Osaka
Osaka |
|
JP
JP
JP
JP |
|
|
Assignee: |
DAIKIN INDUSTRIES, LTD.
Osaka-shi, Osaka
JP
|
Family ID: |
46515547 |
Appl. No.: |
13/980588 |
Filed: |
January 23, 2012 |
PCT Filed: |
January 23, 2012 |
PCT NO: |
PCT/JP2012/000370 |
371 Date: |
July 19, 2013 |
Current U.S.
Class: |
165/181 |
Current CPC
Class: |
F28F 2215/12 20130101;
F28F 1/325 20130101; F28F 1/128 20130101; F28F 17/005 20130101;
F28D 1/053 20130101; F28F 1/022 20130101; F28F 1/12 20130101 |
Class at
Publication: |
165/181 |
International
Class: |
F28F 1/12 20060101
F28F001/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 21, 2011 |
JP |
2011-011195 |
Claims
1-9. (canceled)
10. A heat exchanger, comprising: a plurality of flat tubes
arranged one above another such that flat surfaces thereof face
each other and each having therein a passage of a fluid; and a
plurality of fins configured to divide a space between adjacent
ones of the flat tubes into a plurality of air passages through
which air flows, each of the plurality of fins including a
plurality of plate-like heat-transfer portions each of which
extends from one to the other of the adjacent flat tubes and
comprises a side wall of each of the air passages, and a downwind
side plate connected to a downwind side edge of each of the
heat-transfer portions and serving as a discharge path, wherein
each of the plurality of heat-transfer portions has a plurality of
protrusions which are protruded toward the air passage and extend
in a direction intersecting with an airflow direction, and the
plurality of protrusions are arranged in the airflow direction, the
plurality of protrusions include an upwind protrusion provided at
an upwind side of the air passage, and a downwind protrusion
provided at a downwind side of the air passage, and in the
heat-transfer portion, a height of a flat portion provided in an
area between the upwind protrusion and the flat tube located below
is greater than a height of a flat portion provided in an area
between the downwind protrusion and the flat tube located
below.
11. A heat exchanger, comprising: a plurality of flat tubes
arranged one above another such that flat surfaces thereof face
each other and each having therein a passage of a fluid; and a
plurality of fins configured to divide a space between adjacent
ones of the flat tubes into a plurality of air passages through
which air flows, each of the plurality of fins including a
plurality of plate-like heat-transfer portions each of which
extends from one to the other of the adjacent flat tubes and
comprises a side wall of each of the air passages, and a downwind
side plate connected to a downwind side edge of each of the
heat-transfer portions and serving as a discharge path, wherein
each of the plurality of heat-transfer portions has a plurality of
protrusions which are protruded toward the air passage and extend
in a direction intersecting with an airflow direction, and the
plurality of protrusions are arranged in the airflow direction, and
a height including the heights of the flat portions provided in the
area between the plurality of protrusions and the flat tube located
below is reduced in a direction from the upwind side to the
downwind side.
12. A heat exchanger, comprising: a plurality of flat tubes
arranged one above another such that flat surfaces thereof face
each other and each having therein a passage of a fluid; and a
plurality of fins configured to divide a space between adjacent
ones of the flat tubes into a plurality of air passages through
which air flows, each of the plurality of fins including a
plurality of plate-like heat-transfer portions each of which
extends from one to the other of the adjacent flat tubes and
comprises a side wall of each of the air passages, and a downwind
side plate connected to a downwind side edge of each of the
heat-transfer portions and serving as a discharge path, wherein
each of the plurality of heat-transfer portions has a plurality of
protrusions which are protruded toward the air passage and extend
in a direction intersecting with an airflow direction, and the
plurality of protrusions are arranged in the airflow direction, and
the height of the flat portion provided in the area between a lower
end of at least one protrusion of the plurality of protrusions and
the flat tube located below the lower end of the protrusion is
reduced in the direction from the upwind side to the downwind
side.
13. The heat exchanger of claim 10, wherein the protrusion is
tilted with respect to a vertical direction such that a lower end
of the protrusion is located downwind of an upper end of the
protrusion.
14. The heat exchanger of claim 10, wherein each of the plurality
of fins is in a plate-like shape having, in an upwind side thereof,
a plurality of cutouts for inserting the flat tubes; the fins are
arranged in an extension direction of the flat tube, with a
predetermined space between adjacent ones of the fins; and the flat
tube is fitted to a periphery of the cutout, and in the fin, an
area between vertically adjacent ones of the cutouts comprises the
heat-transfer portion, and a vertically extending portion
continuous with the downwind side edge of each of the heat-transfer
portions comprises the downwind side plate.
15. The heat exchanger of claim 14, wherein the downwind side plate
is provided with a rib extending along the downwind side edges of
the plurality of heat-transfer portions.
16. The heat exchanger of claim 14, wherein the fin includes a
raised portion that is cut and bent toward the air passage, and a
bent surface of the raised portion is tilted with respect to a
horizontal plane.
17. An air conditioner, comprising a refrigerant circuit in which
the heat exchanger of claim 10 is provided, wherein the refrigerant
circuit performs a refrigeration cycle by circulating a
refrigerant.
18. The heat exchanger of claim 11, wherein the protrusion is
tilted with respect to a vertical direction such that a lower end
of the protrusion is located downwind of an upper end of the
protrusion.
19. The heat exchanger of claim 12, wherein the protrusion is
tilted with respect to a vertical direction such that a lower end
of the protrusion is located downwind of an upper end of the
protrusion.
20. The heat exchanger of claim 11, wherein each of the plurality
of fins is in a plate-like shape having, in an upwind side thereof,
a plurality of cutouts for inserting the flat tubes; the fins are
arranged in an extension direction of the flat tube, with a
predetermined space between adjacent ones of the fins; and the flat
tube is fitted to a periphery of the cutout, and in the fin, an
area between vertically adjacent ones of the cutouts comprises the
heat-transfer portion, and a vertically extending portion
continuous with the downwind side edge of each of the heat-transfer
portions comprises the downwind side plate.
21. The heat exchanger of claim 12, wherein each of the plurality
of fins is in a plate-like shape having, in an upwind side thereof,
a plurality of cutouts for inserting the flat tubes; the fins are
arranged in an extension direction of the flat tube, with a
predetermined space between adjacent ones of the fins; and the flat
tube is fitted to a periphery of the cutout, and in the fin, an
area between vertically adjacent ones of the cutouts comprises the
heat-transfer portion, and a vertically extending portion
continuous with the downwind side edge of each of the heat-transfer
portions comprises the downwind side plate.
22. The heat exchanger of claim 13, wherein each of the plurality
of fins is in a plate-like shape having, in an upwind side thereof,
a plurality of cutouts for inserting the flat tubes; the fins are
arranged in an extension direction of the flat tube, with a
predetermined space between adjacent ones of the fins; and the flat
tube is fitted to a periphery of the cutout, and in the fin, an
area between vertically adjacent ones of the cutouts comprises the
heat-transfer portion, and a vertically extending portion
continuous with the downwind side edge of each of the heat-transfer
portions comprises the downwind side plate.
23. The heat exchanger of claim 15, wherein the fin includes a
raised portion that is cut and bent toward the air passage, and a
bent surface of the raised portion is tilted with respect to a
horizontal plane.
24. An air conditioner, comprising a refrigerant circuit in which
the heat exchanger of claim 11 is provided, wherein the refrigerant
circuit performs a refrigeration cycle by circulating a
refrigerant.
25. An air conditioner, comprising a refrigerant circuit in which
the heat exchanger of claim 12 is provided, wherein the refrigerant
circuit performs a refrigeration cycle by circulating a
refrigerant.
26. An air conditioner, comprising a refrigerant circuit in which
the heat exchanger of claim 13 is provided, wherein the refrigerant
circuit performs a refrigeration cycle by circulating a
refrigerant.
27. An air conditioner, comprising a refrigerant circuit in which
the heat exchanger of claim 14 is provided, wherein the refrigerant
circuit performs a refrigeration cycle by circulating a
refrigerant.
28. An air conditioner, comprising a refrigerant circuit in which
the heat exchanger of claim 15 is provided, wherein the refrigerant
circuit performs a refrigeration cycle by circulating a
refrigerant.
29. An air conditioner, comprising a refrigerant circuit in which
the heat exchanger of claim 16 is provided, wherein the refrigerant
circuit performs a refrigeration cycle by circulating a
refrigerant.
Description
TECHNICAL FIELD
[0001] The present invention relates to heat exchangers having a
flat tube and a plurality of fins and configured to exchange heat
between a fluid flowing in the flat tube and air, and air
conditioners having the heat exchangers.
BACKGROUND ART
[0002] Heat exchangers having a flat tube and fins have been known.
For example, Patent Document 1 shows a heat exchanger in which a
plurality of flat tubes, each extending in a horizontal direction,
are arranged one above another with a predetermined space between
the flat tubes, and plate-like fins are arranged in a direction
along which the flat tubes extend, with a predetermined space
between the fins. Further, Patent Document 2 and Patent Document 3
show heat exchangers in which a plurality of flat tubes, each
extending in a horizontal direction, are arranged one above another
with a predetermined space between the flat tubes, and a corrugated
fin is provided between adjacent flat tubes. In these heat
exchangers, air flowing in contact with the fins exchanges heat
with a fluid flowing in the flat tubes.
[0003] In general, fins of the heat exchanger of this type include
louvers which promote heat transfer. The louvers are formed by
cutting and bending part of the fins. It is advantageous to make
the length of each louver as long as possible so that the heat
transfer properties of the fins are increased. Thus, as shown in
FIG. 2 of Patent Document 2 and FIG. 4 of Patent Document 3, fins
of the conventional heat exchangers include louvers each having a
width almost equal to the width of the fin and arranged in a
direction in which air passes.
CITATION LIST
Patent Document
[0004] Patent Document 1: Japanese Patent Publication No.
2003-262485 [0005] Patent Document 2: Japanese Patent Publication
No. 2010-002138 [0006] Patent Document 3: Japanese Patent
Publication No. H11-294984
SUMMARY OF THE INVENTION
Technical Problem
[0007] A refrigerant circuit of an air conditioner is provided with
an outdoor heat exchanger in which a refrigerant is heat exchanged
with outdoor air. The outdoor heat exchanger functions as an
evaporator in a heating operation of the air conditioner. When the
evaporation temperature of the refrigerant in the outdoor heat
exchanger is below 0.degree. C., moisture in the air turns into
frost (i.e., ice) and adheres to the outdoor heat exchanger.
Therefore, during a heating operation under low outdoor air
temperature conditions, defrosting is performed at predetermined
time interval, for example, to melt the frost adhering to the
outdoor heat exchanger. During defrosting, a high temperature
refrigerant is supplied to the outdoor heat exchanger, and the
frost adhering to the outdoor heat exchanger is melted by the
refrigerant. As a result, the frost on the outdoor heat exchanger
melts into drain water, and is discharged from the outdoor heat
exchanger.
[0008] Heat exchangers having flat tubes arranged one above another
can be used as an outdoor heat exchanger of an air conditioner.
However, in this heat exchanger, the flat surfaces of the flat
tubes face upward, and therefore, drain water can be easily
accumulated on the flat tubes. In particular, if a fin includes a
plurality of louvers on its surface, the drain water enters through
the slits of the cut and bent louvers, and accumulates at the
slits. The drain water accumulated around the fins may block heat
transfer from the refrigerant to the frost, and it may take a long
time to melt the frost completely.
[0009] The present invention is thus intended to promote discharge
of drain water, and reduce a time necessary for defrosting, in a
heat exchanger having flat tubes arranged one above another.
Solution to the Problem
[0010] The first aspect of the present invention is directed to a
heat exchanger, including: a plurality of flat tubes (33) arranged
one above another such that flat surfaces thereof face each other
and each having therein a passage (34) of a fluid; and a plurality
of fins (35, 36) configured to divide a space between adjacent ones
of the flat tubes (33) into a plurality of air passages (38)
through which air flows, each of the plurality of fins (35, 36)
including a plurality of plate-like heat-transfer portions (37)
each of which extends from one to the other of the adjacent flat
tubes (33) and comprises a side wall of each of the air passages
(38), and a downwind side plate (42, 47) connected to a downwind
side edge of each of the heat-transfer portions (37) and serving as
a discharge path. In the heat exchanger, each of the plurality of
heat-transfer portions (37) has a plurality of protrusions (51, 52,
53) which are protruded toward the air passage (38) and extend in a
direction intersecting with an airflow direction, and the plurality
of protrusions (51, 52, 53) are arranged in the airflow
direction.
[0011] According to the first aspect of the present invention, the
heat exchanger (30) includes a plurality of flat tubes (33) and a
plurality of fins (35, 36). The heat-transfer portions (37) of the
fins (35, 36) are disposed in the space between vertically adjacent
ones of the flat tubes (33). Thus, the air passages (38) are formed
in the space between the flat tubes (33). The heat exchanger (30)
exchanges heat between the air flowing in the air passages (38) and
a fluid flowing in the passage (34) inside each flat tube (33).
[0012] The heat-transfer portion (37) of the present invention has
a plurality of protrusions (51, 52, 53) which are protruded toward
the air passage (38), and the protrusions (51, 52, 53) are arranged
in the airflow direction in the air passage (38). The plurality of
protrusions (51, 52, 53) increase the heat transfer properties of
the heat-transfer portion (37).
[0013] When the temperature of the fluid flowing in the flat tube
(33) is below 0.degree. C., the moisture in the air turns into
frost and adheres to the surface of the heat-transfer portion (37).
During defrosting operation for melting the frost, water (i.e.,
drain water) melted from the frost on the surface of the
heat-transfer portion (37) is generated. Unlike conventional
louvers, the protrusions (51, 52, 53) of the heat-transfer portion
(37) of the present invention are not formed by cutting and bending
part of the heat-transfer portion (37). This means that the
protrusions (51, 52, 53) of the present invention have no cut in
which the drain water accumulates, and therefore, the drain water
around the protrusions (51, 52, 53) smoothly flows to the downwind
side. The drain water is discharged downward along the wall surface
of the downwind side plate (42, 47).
[0014] The second aspect of the present invention is that in the
first aspect of the present invention, the plurality of protrusions
(51, 52, 53) include an upwind protrusion (51) provided at an
upwind side of the air passage (38), and a downwind protrusion (53)
provided at a downwind side of the air passage (38), and in the
heat-transfer portion (37), a height of a flat portion (51a)
provided in an area between the upwind protrusion (51) and the flat
tube (33) located below is greater than a height of a flat portion
(53a) provided in an area between the downwind protrusion (53) and
the flat tube (33) located below.
[0015] The heat-transfer portion (37) of the second aspect of the
present invention has an upwind protrusion (51) closer to the
upwind side, and a downwind protrusion (53) closer to the downwind
side. In the case where the temperature of the fluid flowing in the
flat tube (33) is below 0.degree. C., and frost adheres to the
surface of the heat-transfer portion (37), the amount of frost
adhering to the upwind protrusion (51) is greater than the amount
of frost adhering to the downwind protrusion (53). Thus, during
defrosting, the amount of drain water generated at the upwind
protrusion (51) is greater than the amount of drain water generated
at the downwind protrusion (53). In the present invention, the
height of the flat portion (51a) on the lower side of the upwind
protrusion (51) is greater than the height of the flat portion
(53a) on the lower side of the downwind protrusion (53). Thus,
during defrosting, a considerable amount of drain water generated
around the upwind protrusion (51) flows down smoothly along the
flat portion (51a) on the lower side of the upwind protrusion
(51).
[0016] The third aspect of the present invention is that in the
first or second aspect of the present invention, a height including
the heights of the flat portions (51a, 52a, 53a) provided in the
area between the plurality of protrusions (51, 52, 53) and the flat
tube (33) located below is reduced in a direction from the upwind
side to the downwind side.
[0017] According to the third aspect of the present invention, a
height including the heights of the flat portions (51a, 52a, 53a)
on the lower side of the plurality of protrusions (51, 52, 53) is
reduced in a direction from the upwind side to the downwind side.
In other words, in the adjacent heat-transfer portions (37), the
height of the gap along the flat portions (51a, 52a, 53a) is
reduced with decreasing distance to the downwind side. Thus, during
defrosting, the drain water generated around the upwind protrusion
(51) is drawn to the downwind side of the heat-transfer portion
(37) by capillary action.
[0018] The fourth aspect of the present invention is that in any
one of the first to third aspects of the present invention, the
protrusion (51, 52, 53) is tilted with a vertical direction such
that a lower end of the protrusion (51, 52, 53) is located downwind
of an upper end of the protrusion (51, 52, 53).
[0019] According to the fourth aspect of the present invention, the
protrusion (51, 52, 53) is tilted with respect to a vertical
direction such that the lower end of the protrusion (51, 52, 53) is
located downwind of the upper end of the protrusion (51, 52, 53).
Thus, the drain water generated around the protrusions (51, 52, 53)
during defrosting is guided by the protrusions (51, 52, 53) and
flows down to the downwind side.
[0020] The fifth aspect of the present invention is that in any one
of the first to fourth aspects of the present invention, the height
of the flat portion (51a, 51b) provided in the area between at
least one protrusion (51, 52) of the plurality of protrusions (51,
52, 53) and the flat tube (33) located below the protrusion (51,
52) is reduced in the direction from the upwind side to the
downwind side.
[0021] According to the fifth aspect of the present invention, the
height of the flat portion (51a, 52a) on the lower side of at least
one protrusion (51, 52) of the plurality of protrusions (51, 52,
53) is reduced in the direction from the upwind side to the
downwind side. In other words, in the adjacent heat-transfer
portions (37), the height of the gap along the flat portions (51a,
52a, 53a) is reduced with decreasing distance to the downwind side.
Thus, during defrosting, the drain water generated around the
protrusion (51, 52) is drawn to the downwind side of the
heat-transfer portion (37) by capillary action.
[0022] The sixth aspect of the present invention is that in any one
of the first to fifth aspects of the present invention, each of the
plurality of fins (36) is in a plate-like shape having, in an
upwind side thereof, a plurality of cutouts (45) for inserting the
flat tubes (33); the fins (36) are arranged in an extension
direction of the flat tube (33), with a predetermined space between
adjacent ones of the fins (36); and the flat tube (33) is fitted to
a periphery of the cutout (45), and in the fin (36), an area
between vertically adjacent ones of the cutouts (45) comprises the
heat-transfer portion (37), and a vertically extending portion
continuous with the downwind side edge of each of the heat-transfer
portions (37) comprises the downwind side plate (47).
[0023] According to the sixth aspect of the present invention, a
downwind side plate (47) is formed on the downwind side of the
plurality of heat-transfer portions (37), which are arranged one
above another, such that the downwind side plate (47) is continuous
with the plurality of heat-transfer portions. Thus, an integrally
formed, elongated fin (36) is obtained. The flat tube (33) is
fitted to the periphery of the cutout (45) formed in each of the
fins (36), and therefore, a plurality of air passages (38) are
formed by being surrounded by adjacent flat tubes (33) and the
heat-transfer portions (37).
[0024] The seventh aspect of the present invention is that in the
sixth aspect of the present invention, the downwind side plate (47)
is provided with a rib (57) extending along the downwind side edges
of the plurality of heat-transfer portions (37).
[0025] According to the seventh aspect of the present invention,
the drain water generated at the heat-transfer portions (37) during
defrosting flows to the downwind side plate (47), and flows down
along the rib (57).
[0026] The eighth aspect of the present invention is that in the
sixth or seventh aspect of the present invention, the fin (36)
includes a raised portion (61, 62) that is cut and bent toward the
air passage (38), and a bent surface (61a, 62a) of the raised
portion (61, 62) is tilted with respect to a horizontal plane.
[0027] According to the eighth aspect of the present invention, the
fin (36) includes a raised portion (61, 62). The tip of the raised
portion (61, 62) is brought into contact with the adjacent fin
(36), thereby keeping a predetermined space between two adjacent
fins (36). The provision of a raised portion like the raised
portion (61, 62) may cause a situation where drain water generated
during defrosting is retained on the upper surface of the raised
portion (61, 62). However, the raised portion (61, 62) of the
present invention is tilted with respect to the horizontal plane,
and therefore, the drain water on the upper surface of the raised
portion (61, 62) is smoothly flows down.
[0028] The ninth aspect of the present invention is directed to an
air conditioner (10), and includes refrigerant circuit (20) in
which the heat exchanger (30) of any one of the first to eighth
aspects of the present invention is provided, wherein the
refrigerant circuit (20) performs a refrigeration cycle by
circulating a refrigerant.
[0029] According to the ninth aspect of the present invention, the
heat exchanger (30) of any one of the first to eighth aspects of
the present invention is connected to a refrigerant circuit (20).
In the heat exchanger (30), the refrigerant circulating in the
refrigerant circuit (20) flows in the passage (34) of the flat tube
(33) and exchanges heat with the air flowing in the air passage
(39).
Advantages of the Invention
[0030] In the present invention, part of each of the heat-transfer
portions (37) of the plurality of fins (35, 36) is protruded toward
the air passage (38), thereby forming a plurality of protrusions
(51, 52, 53). The protrusions (51, 52, 53) can promote heat
transfer between air and a fluid. In addition, the protrusions (51,
52, 53) of the present invention are not in such a shape that is
formed by giving a cut in the heat-transfer portion and bending the
cut portion, unlike the conventional louvers. Thus, the protrusions
(51, 52, 53) do not easily accumulate drain water melted from frost
during defrosting, and thus, the drain water can be smoothly
discharged to the downwind side. As a result, the time necessary
for defrosting can be reduced.
[0031] In the second aspect of the present invention, the height of
the flat portion (51a) on the lower side of the upwind protrusion
(51) is greater than the height of the flat portion (53a) on the
lower side of the downwind protrusion (53). Much frost adheres
particularly on the surface of the upwind protrusion (51), and a
considerable amount of drain water is accordingly generated on the
surface of the upwind protrusion (51) during defrosting. However, a
sufficient gap is provided along the flat portion (51a) on the
lower side of the upwind protrusion (51), and thus, the
considerable amount of drain water generated at the upwind
protrusion (51) can be smoothly discharged.
[0032] In the third aspect of the present invention, the height of
the downwind flat portion (53a) is reduced, thereby making it
possible to draw the drain water accumulated on the upper surface
of the flat tube (33) located below to the downwind side by
capillary action.
[0033] In the fourth aspect of the present invention, the
protrusion (51, 52, 53) is tilted such that the lower end of the
protrusion (51, 52, 53) is located downwind of the upper end of the
protrusion (51, 52, 53). Thus, water melted from frost on the
surface of the protrusion (51, 52, 53) can be smoothly discharged
to the downwind side.
[0034] In the fifth aspect of the present invention, the height of
the flat portion (51a, 52a) on the lower side of at least one
protrusion (51, 52) is gradually reduced with decreasing distance
to the downwind side, thereby making it possible to draw drain
water accumulated on the upper surface of the flat tube (33) to the
downwind side by capillary action.
[0035] In the seventh aspect of the present invention, downwind
side edges of the heat-transfer portions (37) arranged one above
another are connected by a downwind side plate (47), and a rib (57)
is formed on the downwind side plate (47). Thus, the drain water
having moved to the downwind side plate (47) from the heat-transfer
portion (37) can be collected on the surface of the rib (57), and
the drain water can be guided downward along the rib (57).
[0036] In the eighth aspect of the present invention, the fin (36)
includes a raised portion (61, 62). The raised portion (61, 62) can
be used as a spacer between adjacent fins (36). Further, the bent
surface (61a, 62a) of the raised portion (61, 62) is tilted with
respect to a horizontal plane, thereby making it possible to
prevent drain water from being accumulated on the upper surface of
the horizontal plane.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] FIG. 1 is a refrigerant circuit diagram showing a schematic
configuration of an air conditioner having a heat exchanger of the
first embodiment.
[0038] FIG. 2 is an oblique view schematically showing the heat
exchanger of the first embodiment.
[0039] FIG. 3 is a partial cross-sectional view of the front side
of the heat exchanger of the first embodiment.
[0040] FIG. 4 is a cross-sectional view of part of the heat
exchanger taken along the line IV-IV of FIG. 3.
[0041] FIG. 5 is a cross-sectional view of a fin taken along the
line V-V of FIG. 4.
[0042] FIG. 6 is an oblique view of the fine of the first
embodiment.
[0043] FIG. 7 is an oblique view schematically showing a heat
exchanger of the second embodiment.
[0044] FIG. 8 is a partial cross-sectional view of the front side
of the heat exchanger of the second embodiment.
[0045] FIG. 9 is a cross-sectional view of part of the heat
exchanger taken along the line IX-IX of FIG. 8.
[0046] FIG. 10 is a cross-sectional view of a fin taken along the
line X-X of FIG. 9.
DESCRIPTION OF EMBODIMENTS
[0047] Embodiments of the present invention will be described in
detail below based on the drawings.
First Embodiment of Invention
[0048] The first embodiment of the present invention will be
described. An exchanger (30) of the first embodiment comprises an
outdoor heat exchanger (23) of an air conditioner (10) described
later.
[0049] --Air Conditioner--
[0050] The air conditioner (10) having the heat exchanger (30) of
the present embodiment will be described with reference to FIG.
1.
[0051] <Configuration of Air Conditioner>
[0052] The air conditioner (10) has an outdoor unit (11) and an
indoor unit (12). The outdoor unit (11) and the indoor unit (12)
are connected to each other via a liquid communication pipe (13)
and a gas communication pipe (14). In the air conditioner (10), a
refrigerant circuit (20) is formed by the outdoor unit (11), the
indoor unit (12), the liquid communication pipe (13), and the gas
communication pipe (14).
[0053] The refrigerant circuit (20) includes a compressor (21), a
four-way valve (22), an outdoor heat exchanger (23), an expansion
valve (24), and an indoor heat exchanger (25). The compressor (21),
the four-way valve (22), the outdoor heat exchanger (23), and the
expansion valve (24) are accommodated in the outdoor unit (11). The
outdoor unit (11) is provided with an outdoor fan (15) configured
to supply outdoor air to the outdoor heat exchanger (23). The
indoor heat exchanger (25) is accommodated in the indoor unit (12).
The indoor unit (12) is provided with an indoor fan (16) configured
to supply indoor air to the indoor heat exchanger (25).
[0054] The refrigerant circuit (20) is a closed circuit filled with
a refrigerant. In the refrigerant circuit (20), a discharge side of
the compressor (21) is connected to a first port of the four-way
valve (22), and a suction side of the compressor (21) is connected
to a second port of the four-way valve (22). In the refrigerant
circuit (20), the outdoor heat exchanger (23), the expansion valve
(24), and the indoor heat exchanger (25) are provided sequentially
from a third port to a fourth port of the four-way valve (22).
[0055] The compressor (21) is a scroll type or rotary type hermetic
compressor (21). The four-way valve (22) switches between a first
state (the state shown in solid line in FIG. 1) in which the first
port communicates with the third port, and the second port
communicates with the fourth port, and a second state (the state
shown in broken line in FIG. 1) in which the first port
communicates with the fourth port, and the second port communicates
with the third port. The expansion valve (24) is a so-called
electronic expansion valve (24).
[0056] In the outdoor heat exchanger (23), the outdoor air is heat
exchanged with the refrigerant. The outdoor heat exchanger (23) is
comprised of the heat exchanger (30) of the present embodiment. In
the indoor heat exchanger (25), the indoor air is heat exchanged
with the refrigerant. The indoor heat exchanger (25) is comprised
of a so-called cross-fin type fin-and-tube heat exchanger having a
circular heat-transfer tube.
[0057] <Cooling Operation>
[0058] The air conditioner (10) performs a cooling operation. The
four-way valve (22) is set to the first state during the cooling
operation. The outdoor fan (15) and the indoor fan (16) are driven
during the cooling operation.
[0059] The refrigerant circuit (20) performs a refrigeration cycle.
Specifically, the refrigerant discharged from the compressor (21)
passes through the four-way valve (22), flows into the outdoor heat
exchanger (23), and dissipates heat to the outdoor air and
condenses. The refrigerant flowing out of the outdoor heat
exchanger (23) expands when it passes through the expansion valve
(24), flows into the indoor heat exchanger (25), and takes heat
from the indoor air and evaporates. The refrigerant flowing out of
the indoor heat exchanger (25) passes through the four-way valve
(22) and is then sucked into the compressor (21) and compressed.
The indoor unit (12) supplies air which has been cooled in the
indoor heat exchanger (25) to an indoor space.
[0060] <Heating Operation>
[0061] The air conditioner (10) performs a heating operation. The
four-way valve (22) is set to the second state during the heating
operation. The outdoor fan (15) and the indoor fan (16) are driven
during the heating operation.
[0062] The refrigerant circuit (20) performs a refrigeration cycle.
Specifically, the refrigerant discharged from the compressor (21)
passes the four-way valve (22), flows into the indoor heat
exchanger (25), and dissipates heat to the indoor air and
condenses. The refrigerant flowing out of the indoor heat exchanger
(25) expands when it passes through the expansion valve (24), flows
into the outdoor heat exchanger (23), and takes heat from the
outdoor air and evaporates. The refrigerant flowing out of the
outdoor heat exchanger (23) passes through the four-way valve (22)
and is then sucked into the compressor (21) and compressed. The
indoor unit (12) supplies air which has been heated in the indoor
heat exchanger (25) to an indoor space.
[0063] <Defrosting Operation>
[0064] As described above, the outdoor heat exchanger (23)
functions as an evaporator in the heating operation. In the
operation under low outdoor air temperature conditions, the
evaporation temperature of the refrigerant in the outdoor heat
exchanger (23) may sometimes be below 0.degree. C. In this case,
the moisture in the outdoor air turns into frost and adheres to the
outdoor heat exchanger (23). To avoid this, the air conditioner
(10) performs a defrosting operation every time a duration of the
heating operation reaches a predetermined value (e.g., several tens
of minutes), for example.
[0065] To start the defrosting operation, the four-way valve (22)
is switched from the second state to the first state, and the
outdoor fan (15) and the indoor fan (16) are stopped. In the
refrigerant circuit (20) during the defrosting operation, a high
temperature refrigerant discharged from the compressor (21) is
supplied to the outdoor heat exchanger (23). The frost adhering to
the surface of the outdoor heat exchanger (23) is heated and melted
by the refrigerant. The refrigerant which dissipates heat in the
outdoor heat exchanger (23) sequentially passes through the
expansion valve (24) and the indoor heat exchanger (25), and is
then sucked into the compressor (21) and compressed. When the
defrosting operation is finished, the heating operation starts
again. That is, the four-way valve (22) is switched from the first
state to the second state, and the outdoor fan (15) and the indoor
fan (16) are driven again.
[0066] --Heat Exchanger of First Embodiment--The heat exchanger
(30) of the present embodiment which comprises the outdoor heat
exchanger (23) of the air conditioner (10) will be described with
reference to FIGS. 2 to 6.
[0067] <General Configuration of Heat Exchanger>
[0068] As shown in FIG. 2 and FIG. 3, the heat exchanger (30) of
the present embodiment includes one first header collecting pipe
(31), one second header collecting pipe (32), a plurality of flat
tubes (33), and a plurality of fins (35). The first header
collecting pipe (31), the second header collecting pipe (32), the
flat tubes (33), and the fins (35) are all aluminum alloy members,
and are attached to one another with solder.
[0069] Both of the first header collecting pipe (31) and the second
header collecting pipe (32) are in an elongated hollow cylindrical
shape, with both ends closed. In FIG. 3, the first header
collecting pipe (31) is provided upright at the left end of the
heat exchanger (30), and the second header collecting pipe (32) is
provided upright at the right end of the heat exchanger (30). In
other words, the first header collecting pipe (31) and the second
header collecting pipe (32) are provided such that their axial
directions are vertical.
[0070] As is also shown in FIG. 4, the flat tube (33) is a
heat-transfer tube having a flat oblong cross section or a
rectangular cross section with rounded corners. In the heat
exchanger (30), the plurality of flat tubes (33) extend in a
horizontal direction, and are arranged such that the flat surfaces
thereof face each other. Further, the plurality of flat tubes (33)
are arranged one above another with a predetermined space between
the flat tubes (33). One end of each of the flat tubes (33) is
inserted in the first header collecting pipe (31), and the other
end of the flat tube (33) is inserted in the second header
collecting pipe (32).
[0071] As shown in FIG. 4, each flat tube (33) has a plurality of
fluid passages (34). Each fluid passage (34) extends in a direction
in which the flat tubes (33) extend. In the flat tube (33), the
plurality of fluid passages (34) are aligned in a width direction
of the flat tube (33) which is orthogonal to the direction in which
the flat tube (33) extends. One end of each of the plurality of
fluid passages (34) formed in each flat tube (33) communicates with
the interior space of the first header collecting pipe (31), and
the other end of the fluid passage (34) communicates with the
interior space of the second header collecting pipe (32). The
refrigerant supplied to the heat exchanger (30) exchanges heat with
the air, while flowing in the fluid passages (34) of the flat tubes
(33).
[0072] Each of the fins (35) is a corrugated fin which curves up
and down and is placed between vertically adjacent flat tubes (33).
As will be described in detail later, the fin (35) includes a
plurality of heat-transfer portions (37) and a plurality of
intermediate plates (41). The intermediate plates (41) of each fin
(35) are attached to the flat tubes (33) with solder.
[0073] <Configuration of Fin>
[0074] As shown in FIG. 6, the fin (35) is a corrugated fin
obtained by bending a metal plate of a given width, and in a shape
which curves up and down. The fin (35) includes the heat-transfer
portions (37) and the intermediate plates (41) alternately arranged
in the extension direction of the flat tube (33). In other words,
the fin (35) includes a plurality of heat-transfer portions (37)
arranged in the extension direction of the flat tube (33) and
placed between adjacent flat tubes (33). The fin (35) further
includes a projecting plate (42) on the downwind side.
[0075] The heat-transfer portion (37) is a plate-like portion which
extends from one to the other of vertically adjacent flat tubes
(33). The heat-transfer portions (37) are side walls of air
passages (38) formed in the space between adjacent flat tubes (33).
The upwind side edge of the heat-transfer portion (37) is a leading
edge (39). The intermediate plate (41) is a plate-like portion
along the flat surface of the flat tube (33), and is continuous
with the upper ends or the lower ends of the horizontally adjacent
heat-transfer portions (37). The heat-transfer portion (37) and the
intermediate plate (41) form an approximately right angle.
[0076] The projecting plate (42) is a plate-like portion continuous
with the downwind side edge of each heat-transfer portion (37). The
projecting plate (42) is an elongated plate which extends
vertically, and projects further to the downwind side than the flat
tube (33). The upper end of the projecting plate (42) projects
upward from the upper end of the heat-transfer portion (37), and
the lower end of the projecting plate (42) projects downward from
the lower end of the heat-transfer portion (37). As shown in FIG.
4, in the heat exchanger (30), the projecting plates (42) of
vertically adjacent fins (35) which are arranged with a flat tube
(33) interposed therebetween are in contact with each other. The
vertically continuous projecting plates (42) comprise a downwind
side plate which forms a discharge path for drain water.
[0077] As shown in FIG. 4, the heat-transfer portion (37) and the
projecting plate (42) of the fin (35) are provided with a plurality
of waffle portions (51, 52, 53). The waffle portions (51, 52, 53)
comprise a protrusion extending vertically. Each of the waffle
portions (51, 52, 53) is protruded toward the air passage (38) into
a mountain-like shape such that the ridge of each waffle portion
(51, 52, 53) intersects with airflow. The waffle portions (51, 52,
53) are formed by plastically deforming part of the heat-transfer
portion (37) by e.g., press work. Each of the waffle portions (51,
52, 53) extends obliquely with respect to the vertical direction
such that the lower end of each waffle portion is positioned
downwind of the upper end of the waffle portion.
[0078] Each of the waffle portions (51, 52, 53) includes a pair of
trapezoidal surfaces (54, 54) extending vertically, and a pair of
flat triangular surfaces (55, 55) at the upper and lower locations.
The pair of trapezoidal surfaces (54, 54) are arranged next to each
other in the airflow direction, and forms a mountain fold portion
(56), i.e., a ridge, in the middle of the pair of trapezoidal
surfaces (54, 54). The pair of triangular surfaces (55, 55) are
positioned at the upper and lower locations with the mountain fold
portion (56) interposed therebetween.
[0079] The heat-transfer portion (37) is provided with the
plurality of waffle portions (51, 52, 53) sequentially arranged
from the upwind side to the downwind side. The waffle portions (51,
52, 53) include one upwind waffle portion (51) located on the
upwind side of the heat-transfer portion (37), two downwind waffle
portions (53, 53) located on the downwind side of the heat-transfer
portion (37), and one intermediate waffle portion (52) located
between the upwind waffle portion (51) and the downwind waffle
portion (53). The upwind waffle portion (51) comprises an upwind
protrusion located on the most upwind side among the plurality of
waffle portions (51, 52, 53). The downwind waffle portions (53, 53)
comprise a downwind protrusion located on the most downwind side
among the plurality of waffle portions (51, 52, 53).
[0080] The upper end of the upwind waffle portion (51) is located
lower than the upper end of the downwind waffle portion (53). The
upper end of the intermediate waffle portion (52) and the upper
ends of the downwind waffle portions (53) are at approximately the
same height. The upper end of the upwind waffle portion (51), the
upper end of the intermediate waffle portion (52), and the upper
ends of the downwind waffle portions (53) are approximately
parallel to the flat surface of the flat tube (33) located
above.
[0081] The lower end of the upwind waffle portion (51) is located
higher than the lower ends of the downwind waffle portions (53).
The lower end of the upwind waffle portion (51) is tilted such that
a downwind side of the lower end is located lower than an upwind
side of the lower end. The lower end of the intermediate waffle
portion (52) is also tilted such that a downwind side of the lower
end is located lower than an upwind side of the lower end. The
lower ends of the downwind waffle portions (53) are approximately
parallel to the flat surface of the flat tube (33).
[0082] The fin (35) is provided with a water-conducting rib (57) on
the downstream side of the waffle portions (51, 52, 53).
Specifically, one water-conducting rib (57) is provided at each
projecting plate (42). The water-conducting rib (57) extends
vertically along the downwind side edge of the projecting plate
(42). As shown in FIG. 5, the water-conducting rib (57) forms a
raised line (57a) on one surface of the projecting plate (42), and
forms a recessed groove (57b) on the other surface of the
projecting plate (42). The raised lines (57a) are formed in side
surfaces on the same side of the vertically adjacent projecting
plates (42), and the side surfaces on the same side of the
projecting plates (42) adjacent to each other in the extension
direction of the flat tube (33). The vertically adjacent
water-conducting ribs (57) are approximately aligned in the
vertical direction. In the present embodiment, the upper end of the
water-conducting rib (57) is located slightly lower than the upper
end of the projecting plate (42), and the lower end of the
water-conducting rib (57) is located slightly higher than the lower
end of the projecting plate (42). Alternatively, each of the
water-conducting ribs (57) may extend from the upper end to the
lower end of the projecting plate (42).
[0083] Part of the surface of the heat-transfer portion (37) with
no waffle portions (51, 52, 53) and no water-conducting rib (57) is
flat. Flat portions (51a, 51b, 51c) are formed in the area between
the lower ends of the waffle portions (51, 52, 53) and the flat
tube (33) located below the waffle portions (51, 52, 53).
[0084] More specifically, in the heat-transfer portion (37), a
first flat portion (51a) is provided in the area between the lower
end of the upwind waffle portion (51) and the flat tube (33)
located below; a second flat portion (52a) is provided in the area
between the lower end of the intermediate waffle portion (52) and
the flat tube (33) located below; and a third flat portion (53a) is
provided in the area between the lower ends of the downwind waffle
portions (53) and the flat tube (33) located below. In the
heat-transfer portion (37), the height of the first flat portion
(51a) is reduced in a direction from the upwind side to the
downwind side. In the heat-transfer portion (37), the height of the
second flat portion (52a) is reduced as well in the direction from
the upwind side to the downwind side. That is, in the present
embodiment, the heights of the two flat portions (51a, 52a) located
between the lower ends of the two protrusions (51, 52) of the four
protrusions (51, 52, 53, 53) and the flat tube (33) located below
the protrusions (51, 52) are reduced in the direction from the
upwind side to the downwind side. Further, in the heat-transfer
portion (37), the height of the first flat portion (51a) is greater
than the height of each third flat portion (53a). Here, the height
of the flat portion located on the lower side of only one of the
four protrusions (51, 52, 53, 53) may be reduced in the direction
from the upwind side to the downwind side, or heights of three or
more flat portions may be reduced in the direction from the upwind
side to the downwind side.
[0085] --State of Frost and Drain Water in Defrosting
Operation--
[0086] As described above, the heat exchanger (30) of the present
embodiment comprises the outdoor heat exchanger (23) of the air
conditioner (10). The air conditioner (10) performs a heating
operation, but during the operation when the evaporation
temperature of the refrigerant in the outdoor heat exchanger (23)
is below 0.degree. C., the moisture in the outdoor air turns into
frost and adheres to the outdoor heat exchanger (23). Thus, the air
conditioner (10) performs a defrosting operation to melt the frost
adhering to the outdoor heat exchanger (23). Drain water is
generated in the defrosting operation due to melting of the
frost.
[0087] The fins have a considerable amount of frost on the
heat-transfer portions (37), and the space between adjacent
heat-transfer portions (37) is almost clogged with the frost
shortly before start of the defrosting operation. The heat-transfer
portion (37) of the present embodiment shown in FIG. 4 has much
frost particularly on the surface of the upwind waffle portion (51)
on the upwind side. However, because a gap is provided along the
first flat portion (51a) on the lower side of the upwind waffle
portion (51), and air can easily flow through this gap, the
moisture in the air can turn into frost and easily adhere to a
lower portion of the intermediate waffle portion (52) and a lower
portion of the downwind waffle portion (53), as well, in the
heat-transfer portion (37).
[0088] As described above, in the heat exchanger (30) of the
present embodiment, the height of the first flat portion (51a) on
the lower side of the upwind waffle portion (51) is greater than
the heights of the second flat portion (52a) and the third flat
portions (53a). Thus, it is possible to prevent frost from adhering
particularly to the upwind area of the heat-transfer portion (37).
This may increase the time until the heat exchanger (30) is
degraded in performance due to local frost formation in the heating
operation. Since the time from the start of the heating operation
until the start of the defrosting operation is extended, the
duration of the heating operation is accordingly extended.
[0089] Once the defrosting operation has started, the frost
adhering to the heat exchanger (30) is heated by the refrigerant
and gradually melted. As mentioned above, the heat-transfer portion
(37) has much frost particularly on the surface of the upwind
waffle portion (51), and therefore, the amount of water (i.e.,
drain water) melted from the frost is considerable in this area.
Here, the first flat portion (51a) on the lower side of the upwind
waffle portion (51) is greater in height than the other flat
portions (52a, 53a). This means that the upwind waffle portion (51)
has sufficient gap on the lower side thereof, for discharging drain
water. Thus, the drain water melted from the frost adhering to the
upwind waffle portion (51) runs smoothly along the first flat
portion (51a) down to the upper surface of the flat tube (33)
located below.
[0090] The drain water discharged smoothly downward as described
above allows heat of the heat-transfer portion (37) to be easily
transferred to the frost remaining on the surface of the upwind
waffle portion (51). Thus, in the present embodiment, the time
necessary to melt the frost on the surface of the upwind waffle
portion (51) can be reduced, and the duration of the defrosting
operation can also be reduced.
[0091] In general, no frost remains, but drain water exists in the
heat exchanger (30) shortly after the completion of the defrosting
operation. The drain water generated in the defrosting operation
flows to the downwind side. In the present embodiment, the height
of the flat portions (51a, 52a, 53a) is reduced with decreasing
distance to the downwind side, and in particular, the third flat
portion (53a) on the most downwind side has a small height. Thus,
the drain water accumulated on the upper surface of the flat tube
(33) is drawn to the downwind side by capillary action. In other
words, the drain water moves to the downwind side, although the
outdoor fan (15) is stopped in the defrosting operation and the
upper surface of the flat tube (33) is approximately
horizontal.
[0092] Each of the plurality of waffle portions (51) is tilted with
respect to the vertical direction such that the lower end of each
waffle portion (51) is positioned downwind of the upper end of the
waffle portion (51). Thus, the drain water melted from the frost on
the surface of the waffle portion (51) moves to the downwind side
along the direction of tilt of the waffle portion (51).
[0093] The drain water having moved to the downwind side arrives at
the water-conducting rib (57) of the projecting plate (42). The
drain water moves on the surface of the raised line (57a) of the
water-conducting rib (57), or on the inner side of the recessed
groove (57b), and flows down by gravity. The drain water having
flowed down from the projecting plate (42) is guided by the
water-conducting rib (57) of the projecting plate (42) located
below, and flows further down. As a result, the drain water flows
to the bottommost fin (35) and is then delivered to a discharge
path, such as a drain pan.
Advantages of First Embodiment
[0094] In the first embodiment, as shown in FIG. 4, the
heat-transfer portion (37) is provided with a plurality of waffle
portions (51, 52, 53). The waffle portions (51, 52, 53) are formed
by protruding part of the heat-transfer portion (37) toward the air
passage (38), and are not formed by giving cuts in the
heat-transfer portion (37) as in the conventional louver case.
Thus, in the present embodiment, the drain water melted from the
frost can be prevented from being accumulated in the cuts of the
heat-transfer portion (37), and can be smoothly discharged.
[0095] In particular, as described above, it is possible to prevent
frost from adhering particularly to the upwind waffle portion (51)
by making the first flat portion (51a) on the lower side of the
upwind waffle portion (51) have a greater height than the third
flat portion (53a) on the lower side of the downwind waffle portion
(53). As a result, the duration of the heating operation can be
extended. Also, the drain water generated on the surface of the
upwind waffle portion (51) can be smoothly discharged downward
along the first flat portion (51a).
[0096] Since the third flat portion (53a) has a smaller height, the
drain water accumulated on the upper surface of the flat tube (33)
can be smoothly delivered to the downwind side by capillary action.
Moreover, since each of the waffle portions (51, 52, 53) is tilted
as shown in FIG. 4, the drain water melted from the frost on the
surfaces of the waffle portions (51, 52, 53) can be guided smoothly
to the downwind side.
[0097] Since it is possible to reduce time for discharging the
drain water in the defrosting operation as described above, it is
also possible to reduce time necessary for melting the frost. As a
result, the time of the defrosting operation can be reduced, and
the heating operation can be accordingly extended.
Second Embodiment of the Invention
[0098] Now, the second embodiment of the present invention will be
described. Similar to the heat exchanger (30) of the first
embodiment, a heat exchanger (30) of the second embodiment
comprises an outdoor heat exchanger (23) of an air conditioner
(10). The heat exchanger (30) of the present embodiment will be
described below with reference to FIGS. 7 to 10.
[0099] <General Configuration of Heat Exchanger>
[0100] As shown in FIG. 7 and FIG. 8, the heat exchanger (30) of
the present embodiment includes one first header collecting pipe
(31), one second header collecting pipe (32), a plurality of flat
tubes (33), and a plurality of fins (36). The first header
collecting pipe (31), the second header collecting pipe (32), the
flat tubes (33), and the fins (36) are all aluminum alloy members,
and are attached to one another with solder.
[0101] The configurations and locations of the first header
collecting pipe (31), the second header collecting pipe (32), and
the flat tubes (33) are the same as those of the heat exchanger
(30) of the first embodiment. That is, both of the first header
collecting pipe (31) and the second header collecting pipe (32) are
in an elongated cylindrical shape. One of the first header
collecting pipe (31) and the second header collecting pipe (32) is
provided at the left end of the heat exchanger (30), and the other
is provided at the right end of the heat exchanger (30). Each of
the flat tubes (33) is a heat-transfer tube having a flat cross
section, and the flat tubes (33) are arranged one above another
such that the flat surfaces thereof face each other. Each flat tube
(33) has a plurality of fluid passages (34). One end of each of the
flat tubes (33) arranged one above another is inserted in the first
header collecting pipe (31), and the other end is inserted in the
second header collecting pipe (32).
[0102] Each fin (36) is in a plate-like shape, and the fins (36)
are arranged in an extension direction of the flat tube (33) with a
predetermined space between the fins (36). In other words, the fins
(36) are arranged to be substantially orthogonal to the extension
direction of the flat tube (33).
[0103] <Configuration of Fin>
[0104] As shown in FIG. 9, each fin (36) is in an elongated
plate-like shape formed by pressing a metal plate. The fin (36) is
provided with a plurality of elongated cutouts (45) each extending
in a width direction of the fin (36) from a leading edge (39) of
the fin (36). The plurality of cutouts (45) are formed in the fin
(36) at predetermined intervals in a longitudinal direction of the
fin (36). A downwind portion of the cutout (45) comprises a tube
insertion portion (46). A width of the tube insertion portion (46)
in a vertical direction is substantially equal to the thickness of
the flat tube (33), and a length of the tube insertion portion (46)
is substantially equal to the width of the flat tube (33). The flat
tube (33) is inserted in the tube insertion portion (46) of the fin
(36) and is attached to the periphery of the tube insertion portion
(46) with solder.
[0105] In the fin (36), an area between adjacent cutouts (45)
comprises a heat-transfer portion (37), and an area on the downwind
side of the tube insertion portion (46) comprises a downwind side
plate (47). That is, the fin (36) includes a plurality of
heat-transfer portions (37) arranged one above another, with the
flat tube (33) interposed between adjacent heat-transfer portions
(37), and one continuous downwind side plate (47) on the downwind
side edges of the heat-transfer portions (37). In the heat
exchanger (30) of the present embodiment, the heat-transfer portion
(37) of the fin (36) is located between the vertically adjacent
flat tubes (33), and the downwind side plate (47) protrudes further
to the downwind side than the flat tube (33).
[0106] As shown in FIG. 9, the heat-transfer portion (37) and the
downwind side plate (47) of the fin (35) are provided with a
plurality of waffle portions (51, 52, 53), similar to the first
embodiment. That is, the waffle portions (51, 52, 53) are protruded
toward the air passage (38), and comprises a protrusion extending
vertically. The waffle portions (51, 52, 53) are formed by
plastically deforming part of the heat-transfer portion (37) by
e.g., press work. Each of the waffle portions (51, 52, 53) extends
obliquely with respect to the vertical direction such that the
lower end of each waffle portion is positioned downwind of the
upper end of the waffle portion. Similar to the first embodiment,
each of the waffle portions (51, 52, 53) includes a pair of
+trapezoidal surfaces (54, 54), a pair of triangular surfaces (55,
55), and a mountain fold portion (56).
[0107] The heat-transfer portion (37) is provided with one upwind
waffle portion (51), one intermediate waffle portion (52), and two
downwind waffle portions (53, 53) sequentially arranged from the
upwind side to the downwind side. One of the two downwind waffle
portions (53, 53) which is closer to the downwind side is astride
the heat-transfer portion (37) and the downwind side plate
(47).
[0108] In the second embodiment, as well, flat portions (51a, 51b,
51c) are formed in the area between the lower ends of the waffle
portions (51, 52, 53) and the flat tube (33) located below the
waffle portions (51, 52, 53). Specifically, in the heat-transfer
portion (37), a first flat portion (51a) is provided in the area
between the lower end of the upwind waffle portion (51) and the
flat tube (33) located below; a second flat portion (52a) is
provided in the area between the lower end of the intermediate
waffle portion (52) and the flat tube (33) located below; and a
third flat portion (53a) is provided in the area between the lower
ends of the downwind waffle portions (53) and the flat tube (33)
located below. In the heat-transfer portion (37), the height of the
first flat portion (51a) is reduced in the direction from the
upwind side to the downwind side. In the heat-transfer portion
(37), the height of the second flat portion (52a) is reduced as
well in the direction from the upwind side to the downwind side.
That is, in the present embodiment, the heights of the two flat
portions (51a, 52a) located between the lower ends of the two
protrusions (51, 52) of the four protrusions (51, 52, 53, 53) and
the flat tube (33) located below the protrusions (51, 52) are
reduced in the direction from the upwind side to the downwind side.
Further, in the heat-transfer portion (37), the height of the first
flat portion (51a) is greater than the height of each third flat
portion (53a). Here, the height of the flat portion located on the
lower side of only one of the four protrusions (51, 52, 53, 53) may
be reduced in the direction from the upwind side to the downwind
side, or heights of three or more flat portions may be reduced in
the direction from the upwind side to the downwind side.
[0109] The downwind side plate (47) of the fin (36) extends
vertically and forms a discharge path of drain water. The downwind
side plate (47) is provided with one water-conducting rib (57). The
water-conducting rib (57) is an elongated recessed groove extending
vertically along the downwind side edge of the downwind side plate
(47), and extends from the upper end to the lower end of the
downwind side plate (47). As shown in FIG. 10, the water-conducting
rib (57) forms a raised line (57a) on one surface of the downwind
side plate (47), and forms a recessed groove (57b) on the other
surface of the downwind side plate (47). The raised lines (57a) are
formed in the side surfaces on the same side of the downwind side
plates (47) adjacent to each other in the extension direction of
the flat tube (33).
[0110] The fin (36) is provided with tabs (61, 62) configured to
keep a space between adjacent fins (36). Each of the tabs (61, 62)
is a small rectangular piece formed by cutting and bending part of
the fin (36).
[0111] As shown in FIG. 9, an upwind tab (61) is provided at an
upwind side edge of each heat-transfer portion (37). The upwind tab
(61) is formed by cutting part of the heat-transfer portion (37)
and bending the cut portion obliquely upward. That is, a bent
surface (61a) of the upwind tab (61) is tilted with respect to a
horizontal plane. A downwind tab (62) is provided on the downwind
side plate (47) at a downwind side of each flat tube (33). The
downwind tab (62) is formed by cutting part of the downwind side
plate (47) and bending the cut portion to the upwind side. That is,
a bent surface (62a) of the downwind tab (62) is orthogonal to the
horizontal plane.
[0112] The bent surface of each of the tabs (61, 62) has a height
that allows the tabs (61, 62) to be in contact with the adjacent
fin (36). That is, the tabs (61, 62) serve as spacers which keep a
predetermined space between adjacent fins (36). The tabs (61, 62)
may be unfolded to the original state of the fin (36) after the
fins (36) are soldered to the flat tubes (33).
Advantages of Second Embodiment
[0113] The heat exchanger (30) of the second embodiment can have
similar advantages as those in the first embodiment. Specifically,
the heat transfer properties can be improved in the second
embodiment, as well, because a plurality of waffle portions (51,
52, 53) are provided on the heat-transfer portion (37). Unlike the
conventional louvers, the waffle portions (51, 52, 53) do not
require cuts, and thus, no drain water accumulates around the
waffle portions (51, 52, 53). In addition, the first flat portion
(51a) on the lower side of the upwind waffle portion (51) allows
drain water generated on the surface of the upwind waffle portion
(51) to be smoothly discharged downward. The drain water
accumulated on the upper surface of the flat tube (33) can be drawn
to the downwind side from the gap at the third flat portion (53a)
by capillary action. Further, the drain water generated on the
surface of each waffle portion (51, 52, 53) can be guided to the
downwind side along the direction of tilt of each waffle portion
(51, 52, 53).
[0114] The drain water having moved to the downwind side plate (47)
after traveling as described above is collected on the surface of
the raised line (57a) of the water-conducting rib (57), or on the
inner side of the recessed groove (57b), and flows down along the
water-conducting rib (57). As a result, the drain water accumulated
in the downwind area of the fin (36) can be smoothly discharged to
e.g., a drain pan.
[0115] The bent surfaces (61a, 62a) of the tabs (61, 62) of the
second embodiment are tilted with respect to a horizontal plane. It
is thus possible to prevent the drain water generated on the
surface of the fin (36) from being accumulated on upper portions of
the bent surfaces (61a, 62a) of the tabs (61, 62). Thus, airflow in
the air passage (38) is not blocked by refrozen drain water on the
surface of the tabs (61, 62).
[0116] The foregoing embodiments are merely preferred examples in
nature, and are not intended to limit the scope, applications, and
use of the invention.
INDUSTRIAL APPLICABILITY
[0117] As described above, the present invention is useful for a
heat exchanger which has a flat tube and a plurality of fins and
exchanges heat between a fluid flowing in the flat tube and air,
and an air conditioner having the heat exchanger.
DESCRIPTION OF REFERENCE CHARACTERS
[0118] 10 air conditioner [0119] 30 heat exchanger [0120] 33 flat
tube [0121] 34 fluid passage (passage of fluid) [0122] 35 fin
(corrugated fin) [0123] 36 fin [0124] 37 heat-transfer portion
[0125] 38 air passage [0126] 42 projecting plate (downwind side
plate) [0127] 45 cutout [0128] 47 downwind side plate [0129] 51
upwind waffle portion (upwind protrusion, protrusion) [0130] 51a
first flat portion (flat portion) [0131] 52 intermediate waffle
portion (protrusion) [0132] 52a second flat portion (flat portion)
[0133] 53 downwind waffle portion (downwind protrusion, protrusion)
[0134] 53a third flat portion (flat portion) [0135] 57
water-conducting rib (rib) [0136] 91 upwind tab (raised portion)
[0137] 61a bent surface [0138] 62 downwind tab (raised portion)
[0139] 62a bent surface
* * * * *