U.S. patent application number 10/317816 was filed with the patent office on 2003-08-14 for heat exchanger fin for air conditioner.
This patent application is currently assigned to Mando Climate Control Corporation. Invention is credited to Choi, Hyun-joo, Kim, Woo-hyun, Park, In-kyu.
Application Number | 20030150601 10/317816 |
Document ID | / |
Family ID | 27667603 |
Filed Date | 2003-08-14 |
United States Patent
Application |
20030150601 |
Kind Code |
A1 |
Park, In-kyu ; et
al. |
August 14, 2003 |
Heat exchanger fin for air conditioner
Abstract
The present invention discloses a heat exchanger fin having
three rows of slit parts being arranged at the air inlet side and
another three rows at the air outlet side relative to the
centerline of heat transfer pipes 102, in order to reduce the
ventilating resistance, prevent the growth of a boundary layer and
reduce a dead zone on the downstream of the heat transfer pipes 102
to thus increase heat transfer performance. The outer slit parts
111 and 111'; and 116 and 116' at the air inlet side and at the air
outlet side are formed in pairs. The middle slit parts 112 and 112'
at the air inlet side are formed in pairs and the middle slit part
114 at the air outlet side is formed in a unit. The inner slit
parts 113 and 114 at the air inlet side and at the air outlet side
are also formed in a unit. Therefore, the heat exchanger can reduce
the airflow pressure drop and thus can increase air volume, and can
improve the evaporation performance by increasing the heat transfer
rate between the air and the fin surface.
Inventors: |
Park, In-kyu; (Cheonan-shi,
KR) ; Choi, Hyun-joo; (Cheonan-shi, KR) ; Kim,
Woo-hyun; (Seoul, KR) |
Correspondence
Address: |
Cooper & Dunham LLP
1185 Avenue of Americas
New York
NY
10036
US
|
Assignee: |
Mando Climate Control
Corporation
|
Family ID: |
27667603 |
Appl. No.: |
10/317816 |
Filed: |
December 12, 2002 |
Current U.S.
Class: |
165/151 ;
165/182 |
Current CPC
Class: |
F28F 1/325 20130101 |
Class at
Publication: |
165/151 ;
165/182 |
International
Class: |
F28D 001/04; F28F
001/30 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 8, 2002 |
KR |
2002-07586 |
Feb 8, 2002 |
KR |
2002-07587 |
Claims
What is claimed is:
1. A heat exchanger fin for an air conditioner comprising an air
inlet side group of slit parts and an air outlet side group of slit
parts being arranged between two heat transfer pipes, respectively,
each of the slit parts being formed by a pair of rising portions
whose ends project from the fin surface as well as a bridging
portion spanning between the rising portions, central edge portions
which are located at an inlet end portion of the air inlet side and
an outlet end portion of the air outlet side, respectively, and
intermediate flat portions being formed between adjacent those of
the slit parts, the heat exchanger fin characterized in that: the
air inlet side group of slit parts includes a pair of outer slit
parts, a pair of middle slit parts, and an inner slit part
sequentially from the inlet end, wherein each of the first rising
portions of the outer slit parts and the middle slit parts is
parallel to the direction l of air current (A) and each of the
second rising portions of the outer slit parts and the middle slit
parts are parallel to the outer tangential line (m) of the heat
transfer pipes, and the opposite rising portions of the inner slit
part are parallel to the direction of air current (A); and the air
outlet side group of slit parts includes a pair of outer slit
parts, a middle slit part, and an inner slit part sequentially from
the outlet end, wherein the first rising portions of the outer slit
parts are parallel to the direction l of air current (A) and the
second rising portions are parallel to the outer tangential line
(m) of the heat transfer pipes, the opposite rising portions of the
middle slit parts are parallel to the outer tangential line (m) of
the heat transfer pipes, and the opposite rising portions of the
inner slit part are parallel to the direction of air current
(A).
2. The heat exchanger fin of claim 1, characterized in that the
spacing between the first rising portions of the outer slit parts
at the air inlet side is larger than the spacing between the first
rising portions of the middle slit parts, whereby the second rising
portions of the outer slit parts and the middle slit parts are
arranged more adjacently, but approximately the same distance from
the heat transfer pipes.
3. The heat exchanger fin of claim 1, characterized in that the
second rising portions of the middle slit parts at the air inlet
side and the opposite rising portions of the middle slit parts are
arranged adjacent to each other approximately the same distance
from the heat transfer pipes.
4. The heat exchanger fin of claim 1, characterized in that the
slit parts project alternately on the front face and the rear face
of the flat fin, or only on one of the faces of the flat fin.
5. A heat exchanger fin for an air conditioner comprising a first
group of slit parts being arranged between the first heat transfer
pipes and a second group of slit parts being arranged between the
second heat transfer pipes, each of the first and the second group
of slit parts consisting of an air inlet side group of slit parts
and an air outlet side group of slit parts being arranged between
two heat transfer pipes, respectively, each of the slit parts being
formed by a pair of rising portions whose ends project from the fin
surface as well as a bridging portion spanning between the rising
portions, central edge portions which are located at an inlet end
portion of the air inlet side and an outlet end portion of the air
outlet side, respectively, and intermediate flat portions formed
between adjacent those of the slit parts, the heat exchanger fin
characterized in that: each of the air inlet side group of slit
parts of the first and the second group of slit parts includes a
pair of outer slit parts, a pair of middle slit parts, and an inner
slit part sequentially from the inlet end, wherein each of the
first rising portions of the outer slit parts and the middle slit
parts are parallel to the direction l of air current (A) and each
of the second rising portions of the outer slit parts and the
middle slit parts are parallel to the outer tangential line (m) of
the heat transfer pipes, and the opposite rising portions of the
inner slit part are parallel to the direction of air current (A);
and each of the air outlet side group of slit parts of the first
and the second group of slit parts includes a pair of outer slit
parts, a pair of middle slit parts, and an inner slit part
sequentially from the outlet end, wherein the first rising portions
of the outer and the middle slit parts are parallel to the
direction l of air current (A) and the second rising portions are
parallel to the outer tangential line (m) of the heat transfer
pipes, and the opposite rising portions of the inner slit part are
parallel to the direction of air current (A).
6. The heat exchanger fin of claim 5, characterized in that the
spacing between the first rising portions of the outer slit parts
of the first and the second group of slit parts at the air inlet
side is formed larger than the spacing between the first rising
portions of the middle slit parts, and the second rising portions
of the outer slit parts and the middle slit parts are arranged more
adjacently approximately the same distance from the heat transfer
pipe, respectively; and the first rising portion of at least one of
the outer slit parts of the first and the second group of slit
parts at the air inlet side and the first rising portion at least
one of the middle slit parts are arranged in parallel in the
direction of air current.
7. The heat exchanger fin of claim 5, characterized in that the
spacing between the first rising portions of the outer slit parts
of the first and the second group of slit parts at the air outlet
side is formed larger than the spacing between the first rising
portions of the middle slit parts, and second rising portions of
the outer slit parts and the middle slit parts of the first and the
second group of slit parts are arranged more adjacently
approximately the same distance from the heat transfer pipe,
respectively; and the first rising portion of at least one of the
outer slit parts of the first and the second group of slit parts at
the air outlet side and the first rising portion at least one of
the middle slit parts are arranged in parallel in the direction of
air current.
8. The heat exchanger fin of claims 5, characterized in that the
outer slit parts at the air outlet side of the first and the second
group of slit parts are formed in symmetrically with the outer slit
parts at the inlet side relative to the centerline of the first and
second heat transfer pipes, respectively.
9. The heat exchanger fin of claims 5, characterized in that the
middle slit parts at the air outlet side of the first and the
second group of slit parts are formed in asymmetrically with the
middle slit parts at the inlet side relative to the centerline of
the first and second heat transfer pipes, respectively.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a heat exchanger fin for an
air conditioner, and more particularly, to a heat exchanger fin for
an air conditioner which can reduce the airflow pressure drop and
improve evaporation performance by arranging slit parts at the air
inlet side and slit parts at the air outlet side in a different
structure with a line passing through the center of each of the
heat transfer pipes.
[0003] 2. Description of the Related Art
[0004] Generally, the indoor space of a building is contaminated by
internal factors such as the breath of its residents, and thus
needs to be periodically supplied with fresh air from the outside.
Also, in hot summer weather or cold winter weather, a room has to
be cooled or heated to an adequate temperature and has to maintain
an adequate humidity suitable for human activities. For this
purpose, most buildings are equipped with air conditioning
systems.
[0005] Among the air conditioning systems for cooling a room, is
used an air conditioner which cools a given indoor space by
absorbing heat from the air during refrigerant evaporation.
Typically, the air conditioner includes a compressor for
compressing a refrigerant in the form of gas at a high temperature
and high pressure, a condenser for liquefying the compressed
refrigerant into a liquid state, and a heat exchanger evaporating
the refrigerant expanded by an expansion valve. The cooled air,
which is heat-exchanged while passing through the heat exchanger,
is forcedly blown into the room requiring cooling by a blower fan
in an air blower assembly.
[0006] The exchanger of such a type includes heat transfer pipes
made of copper and the like connected with each other by a U-shaped
band and fins made of aluminum and the like, and has a structure in
which the air introduced between the fins are cooled by the
refrigerant passing through the heat transfer pipes.
[0007] Recently, there is an increasing need for further
miniaturization and high performance of heat exchangers. However,
this is accompanied by the problems of deterioration of heat
transmission performance and noise generation. Therefore, there
have been attempts for achieving the miniaturization and high
performance of heat exchangers, enhancing heat transmission
performance and noise reduction.
[0008] Korean Patent No. 1991-3071 applied on Oct. 28, 1988 and
registered on May 17, 1991 discloses a heat exchanger fin for
enhancing heat transmission performance and noise reduction,
simultaneously.
[0009] The shape of fins of the heat exchanger disclosed in the
above-mentioned patent has a structure as shown in FIG. 1. That is
to say, heat transfer pipes 2 are inserted into fin collars 12
formed by burring in a flat fin at predetermined intervals, and an
airflows in the direction of the arrows A.
[0010] The fin 1 has a group of slit parts comprising a total of
six rows of slit parts, that is, three on the air inlet side and
another three on the air outlet side of the air current (A),
between the two heat transfer pipes 2 that are arranged adjacent to
each other in a direction perpendicular to the air current (A)
[0011] The slit parts at the upstream end and the downstream end
comprise a pair of slit parts 14 and 24 separated by a central
dividing flat portion 3a. Each of the other rows of slit parts
includes one slit part 4. Openings 8, 18 and 28 of the six rows of
slit parts are located perpendicular to the direction of air
current (A).
[0012] The rising portions 5, 6, 15 and 25 on the heat transfer
pipe 2 side of the slit parts 4, 14 and 24 are arranged so as to
have angles of inclination in a direction along the outer
tangential line (m) of the heat transfer pipe 2. Rising portions 16
and 26, on the central portion side of the pair of slit parts 14
and 24 at the upstream end or downstream end of air currents, are
formed in a direction parallel to the rising portions 15 and 25.
The pairs of slit parts 14 and 24 are formed in the shape of a
parallelogram.
[0013] The slit parts in the six rows are formed alternately on
both sides of the fin 1 with each intermediate flat portion placed
therebetween.
[0014] In the above-described construction, the heat transfer rate
between the air current and fin surfaces can be improved and thus
heat exchange capacity can be increased. However, noise generation
still remains and there is a limit to improving evaporation
performance.
SUMMARY OF THE INVENTION
[0015] It is, therefore, an object of the present invention to
provide a heat exchanger fin for an air conditioner which can
reduce the airflow pressure drop and improve the evaporation
performance by arranging slit parts at the air inlet side and slit
parts at the air outlet side in a different structure with a line
passing through the center of each of the heat transfer pipes.
[0016] In accordance with one embodiment of the present invention,
a heat exchanger fin for an air conditioner comprising an air inlet
side group of slit parts and an air outlet side group of slit parts
being arranged between two heat transfer pipes, respectively, each
of the slit parts being formed by a pair of rising portions whose
ends project from the fin surface as well as a bridging portion
spanning between the rising portions, central edge portions which
are located at the inlet end portion of the air inlet side and an
outlet end portion of the air outlet side, respectively, and
intermediate flat portions being formed between adjacent those of
the slit parts, is characterized in that: the air inlet side group
of slit parts includes a pair of outer slit parts, a pair of middle
slit parts, and an inner slit part sequentially from the inlet end,
wherein each of the first rising portions of the outer slit parts
and the middle slit parts is parallel to the direction l of air
current (A) and each of the second rising portions of the outer
slit parts and the middle slit parts are parallel to the outer
tangential line (m) of the heat transfer pipes, and the opposite
rising portions of the inner slit part are parallel to the
direction of air current (A); and the air outlet side group of slit
parts includes a pair of outer slit parts, a middle slit part, and
an inner slit part sequentially from the outlet end, wherein the
first rising portions of the outer slit parts are parallel to the
direction l of air current (A) and the second rising portions are
parallel to the outer tangential line (m) of the heat transfer
pipes, the opposite rising portions of the middle slit parts are
parallel to the outer tangential line (m) of the heat transfer
pipes, and the opposite rising portions of the inner slit part are
parallel to the direction of air current (A).
[0017] In accordance with another embodiment of the present
invention, a heat exchanger fin for an air conditioner comprising a
first group of slit parts arranged between the first heat transfer
pipes and a second group of slit parts arranged between the second
heat transfer pipes, each of the first and the second group of slit
parts consisting of an air inlet side group of slit parts and an
air outlet side group of slit parts arranged between two heat
transfer pipes, respectively, each of the slit parts formed by a
pair of rising portions whose ends project from the fin surface as
well as a bridging portion spanning between the rising portions,
central edge portions which are located at the inlet end portion of
the air inlet side and an outlet end portion of the air outlet
side, respectively, and intermediate flat portions being formed
between adjacent those of the slit parts, is characterized in that:
each of the air inlet side group of slit parts of the first and the
second group of slit parts includes a pair of outer slit parts, a
pair of middle slit parts, and an inner slit part sequentially from
the inlet end, wherein each of the first rising portions of the
outer slit parts and the middle slit parts are parallel to the
direction l of air current (A) and each of the second rising
portions of the outer slit parts and the middle slit parts are
parallel to the outer tangential line (m) of the heat transfer
pipes, and the opposite rising portions of the inner slit part are
parallel to the direction of air current (A); and each of the air
outlet side group of slit parts of the first and the second group
of slit parts includes a pair of outer slit parts, a pair of middle
slit parts, and an inner slit part sequentially from the outlet
end, wherein the first rising portions of the outer and the middle
slit parts are parallel to the direction l of air current (A) and
the second rising portions are parallel to the outer tangential
line (m) of the heat transfer pipes, and the opposite rising
portions of the inner slit part are parallel to the direction of
air current (A).
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above objects, features and advantages of the present
invention will become more apparent from the following detailed
description when taken in conjunction with the accompanying
drawings, in which:
[0019] FIG. 1 is a plan view showing the shape of a heat exchanger
fin for an air conditioner according to the prior art;
[0020] FIG. 2 is a perspective view showing the shape of a heat
exchanger fin for an air conditioner according to a preferred
embodiment of the present invention;
[0021] FIG. 3 is a plan view showing the shape of the heat
exchanger fin for an air conditioner according to one embodiment of
the present invention;
[0022] FIG. 4 is a sectional view taken along line IV-IV in FIG.
3;
[0023] FIG. 5 is a sectional view taken along line V-V in FIG. 3;
and
[0024] FIG. 6 is a plan view showing the shape of a heat exchanger
fin for an air conditioner according to another embodiment of the
present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0025] Preferred embodiments of a heat exchanger fin for an air
conditioner of the present invention will now be described with
reference to the accompanying drawings.
[0026] FIGS. 2 to 5 are views showing a heat exchanger fin
according to the preferred embodiment of the present invention.
Here, FIG. 2 is a perspective view showing the shape of a heat
exchanger fin according to the present invention, FIG. 3 is a plan
view showing the shape of the heat exchanger fin according to one
embodiment of the present invention, FIG. 4 is a sectional view
taken along line IV-IV in FIG. 3, and FIG. 5 is a sectional view
taken along line V-V in FIG. 3.
[0027] The shape of the heat exchanger fin for an air conditioner
according to the preferred embodiment of the present invention has
a structure as illustrated in FIG. 2.
[0028] Heat transfer pipes 102 are inserted through a flat fin 100
at predetermined intervals, and airflows in the direction of the
arrow (A) to be heat-exchanged with a refrigerant.
[0029] That is to say, a plurality of flat fins 100 are arranged in
parallel at a predetermined interval, and a plurality of heat
transfer pipes 102 in which refrigerants flow are inserted through
each flat fin 100 in a perpendicular direction.
[0030] The flat fin 100 of the present invention has a group of
slit parts comprising a total of six rows of slit parts: three
(i.e. outer, middle and inner from the air inlet end) slit parts on
the air inlet side; and another three (i.e. outer, middle and inner
from the air inlet end) slit parts on the air outlet side of the
air current (A), between the two heat transfer pipes 102.
[0031] Here, the air inlet side indicates the area in which air
current (A) is introduced and the air outlet side indicates the
area in which air current (A) is discharged, when viewed from the
centerline C-C of the row of the heat transfer pipes 102.
[0032] Central edge flat portions 100a located between the center
area of the heat transfer pipes 102 are formed between a group of
slit parts 111 and 111'; 112 and 112' at the air inlet side and a
group of slit parts 115 and 115'; and 116 and 116' at the air
outlet side.
[0033] Each of the slit parts (for example, 113 and 114 at the
center) in each of the rows is formed by a pair of rising portions
113a and 113b; and 114a and 114b whose ends project from the fin
surface as well as a bridging portion spanning the rising portions
113a and 113b; and 114a and 114b.
[0034] Additionally, the slit parts project alternately on the
front face and the rear face of the flat fin 100, or only-on one of
the faces of the flat fin 100.
[0035] That is, as illustrated in detail in FIGS. 2, 4 and 5, an
outer slit parts 111 and 111', an inner a slit part 113 and a
middle slit part 115 project on the front face of the flat fin 100
sequentially from the shortest from the inlet end. A middle slit
parts 112 and 112', an inner slit parts 114 and an outer slit parts
116 and 116' project on the rear face of the flat fin 100.
[0036] Intermediate flat portions 100b are formed between the slit
parts and each of the six rows of slit parts are arranged in
parallel adjacent to each other.
[0037] Specifically, the group of slit parts 111 and 111'; 112 and
112'; and 113 at the air inlet side is constructed in such a manner
that an inner slit part 113 is located adjacent to the centerline
C-C of the heat transfer pipes 102, the outer slit parts 111 and
111' are located at the inlet end portion, and a middle slit parts
112 and 112' are located between the inner slit part 113 and the
outer slit parts 111 and 111'.
[0038] The outer (first row of) slit parts 111 and 111' and the
middle (second row of) slit parts 112 and 112' are formed in pairs,
and the inner (third row of) slit part 113 is formed in a unit.
First rising portions 111a, 111a', 112a and 112a'of the outer slit
parts 111 and 111' and the middle slit parts 112 and 112' are
formed parallel to the direction l of air current (A), and second
rising portions 111b, 111b', 112b and 112b' are formed in parallel
to the outer tangential line (m) of the heat transfer pipes 102.
Opposite rising portions 113a and 113b of the inner slit part 113
are parallel to the direction of the air current (A).
[0039] The group of slit parts 114; 115; and 116 and 116' at the
air outlet side is constructed in such a manner that the inner
(fourth row of) slit part 114 is located adjacent to the centerline
C-C of the heat transfer pipes
[0040] 102, the outer (sixth row of) slit parts 116 and 116' are
located at the outlet end portion and a middle (fifth row of) slit
part 115 is located between the inner slit part 114 and the outer
slit parts 116 and 116'.
[0041] The outer slit parts 116 and 116' are formed in pairs, being
symmetrical to the outer slit parts 111 and 111' at the inlet end
portion relative to the centerline C-C of the heat transfer pipes
102. First rising portions 116a and 116a' arranged parallel to the
direction of air current (A) and second rising portions 116b and
116b' are arranged parallel to the outer tangential line (m of FIG.
3) of the heat transfer pipe 102.
[0042] Each of the middle slit part 115 and the inner slit parts
114 is formed in a unit. Opposite Rising portions 115a and 115b of
the middle slit part 115 are formed in parallel to the outer
tangential direction of the heat transfer pipes 102 in the same
manner as the second rising portions 116b and 116b' of the outer
slit parts 116 and 116'. Opposite rising portions 114a and 114b of
the inner slit part 114 are formed in parallel to the direction of
air current (A).
[0043] By allowing the air introduced from the air inlet end to the
first and second rows of slit parts 111 and 111'; and 112 and 112'
to flow uniformly on the heat transfer pipes 102 and the base
surface of the flat fin 100, the heat transfer efficiency is
enhanced. Also, by constructing the middle slit part 115 at the
outlet side in a unit, it is possible to prevent heat transfer
capacity from being decreased due to the continuous growth of a
temperature boundary layer on the base surface located between the
slit parts spaced apart from each other.
[0044] When observing an enlarged view of the surface of the area
linking a base surface and rising portions of a projecting portion,
this area protrudes from the base surface to the rising portions of
the projecting portion. Thus the surface roughness giving
resistance to airflow is increased relative to the number of rising
portions on the base surface. The fin surface of the rising
portions is bent, not consistent with a stream flow, whereby the
ventilating resistance is increased.
[0045] Therefore, the middle slit part 115 at the air outlet side
is formed in a unit so that the number of rising portions is
minimized, i.e., two in order to reduce the ventilating resistance.
As another effect of constructing the middle slit part 115 at the
air outlet side in a unit, the reduction of airflow and the
scattering of condensate are prevented by smoothly discharging the
condensate.
[0046] Namely, in a wet coil state which produces condensate, if
the projecting portion is separated, the condensate water is locked
in a vent hole of the projecting portion by the surface tension of
the projecting portion, thereby making it difficult to discharge
the condensate. This causes a decrease of airflow by a rapid
increase of ventilating resistance and greatly reduces the cooling
performance. However, in the present invention, by forming the
middle slit part 115 at the air outlet side in a unit, condensate
is smoothly discharged.
[0047] Since a dead zone formed on the heat transfer pipe at the
exit side causes a loss of flow pressure and a loss in heat
transfer efficiency, it must be minimized to avoid a decrease in
ventilating resistance and heat transfer efficiency. In the present
invention, the second rising portions 116b and 116b' are arranged
adjacent to the heat transfer pipes 102 in order to form the outer
slit parts 116 and 116' located next to the middle slit part 115 at
a location reducing the dead zone on the downstream of the heat
transfer pipe.
[0048] In this case, if the outer slit parts 116 and 116' are
formed integrally, the rigidity of the bridging portion becomes
weak according to an increase of the length of the bridging
portion, whereby the bridging portion is bent or it is vibrated by
airflow, that is, abnormal noise is generated. Thusly the outer
slit parts 116 and 116' are spaced apart in order to reduce the
dead zone on the downstream of the heat transfer pipe, whereby the
rigidity of the bridging portion is maintained.
[0049] The first embodiment is not limited to the example of the
heat transfer pipes being disposed in a row parallel to the
direction of air current, but may also be applied to the heat
transfer pipes being disposed in plural rows parallel to the
direction of air current. Also, in this case, the shape of the slit
parts according to the present invention may be formed in plural
rows parallel to each other relative to the line passing through
the center of the heat transfer pipes.
[0050] Referring to FIG. 6, a heat exchanger according to a second
embodiment of the present invention will now be described in
detail.
[0051] FIG. 6 is a plan view showing the shape of a heat exchanger
fin for an air conditioner according to another embodiment of the
present invention.
[0052] The shape of the flat fin 200 of the heat exchanger
according to the present embodiment has a structure of two rows
type heat transfer pipes 202 and 202' as illustrated therein. That
is, the flat fin 200 of this embodiment comprises a first group of
slit parts being arranged between the first heat transfer pipes
202' and a second group of slit parts being arranged between the
second heat transfer pipes 202. Each of the first and the second
group of slit parts consists of an air inlet side group of slit
parts and an air outlet side group of slit parts being arranged
between the first and the second heat transfer pipes 202' and 202,
respectively.
[0053] Each of the heat transfer pipes 202' and 202 is inserted
through a flat fin 200, and airflows in the direction of the arrow
(A) to thus be heat-exchanged with refrigerant.
[0054] That is to say, a plurality of flat fins 200 are arranged in
parallel at predetermined intervals, and a plurality of heat
transfer pipes 202 and 202' in which refrigerants flow are inserted
through each flat fin 200 in a perpendicular direction.
[0055] The flat fin 200 of the present embodiment has two group of
slit parts comprising each of sixth rows of slit parts, that is,
six on the first group of slit parts between the first heat
transfer pipes 202' and another six on the second group of slit
parts between the second heat transfer pipes 202.
[0056] Here, the air inlet side of the first and second group of
slit parts indicates the area in which air current (A) is
introduced and the air outlet side indicates the area in which air
current (A) is discharged, with respect to the central portion
between the centerline C1-C1 of the first heat transfer pipes 202'
and the centerline C-C of the second heat transfer pipes 202.
[0057] Although, the slit parts of the flat fin 200 will be
described for the second group of slit parts between the second
heat transfer pipes 202, it should be understood that the first
group of slit parts between first the heat transfer pipes 202' has
the same construction as those of the second group of slit
parts.
[0058] Central edge flat portions 200a located between the center
area of the heat transfer pipe 202 are formed between a group of
slit parts 211 and 211'; and 212 and 212' at the air inlet side and
a group of slit parts 215 and 215'; and 216 and 216' at the air
outlet side, with respect to the centerline C-C of the second heat
transfer pipes 202.
[0059] Each of the slit parts (for example, 213 and 214 at the
center) in each of the rows is formed by a pair of rising portions
213a and 213b; and 214a and 214b whose ends project from the fin
surface as well as a bridging portion spanning the rising portions
213a and 213b; and 214a and 214b.
[0060] As above-mentioned in the first embodiment, the slit parts
project alternately on the front face and the rear face of the flat
fin 200, or only on one of the faces of the flat fin 200.
[0061] That is, a outer slit parts 211 and 211', a inner a slit
part 213 and a middle slit parts 215 and 215' project on the front
face of the flat fin 200 sequentially from the one shortest from
the front end portion of the outlet side. A middle slit parts 212
and 212', an inner slit parts 214 and an outer slit parts 216 and
216' project on the rear face of the flat fin 200.
[0062] Intermediate flat portions 200b are formed between each of
the slit parts and the six rows of slit parts are arranged in
parallel adjacent to each other.
[0063] Specifically, the group of slit parts 211 and 211'; 212' and
212'; and 213 at the air inlet side is constructed in such a manner
that an inner slit part 213 is located adjacent to the centerline
C-C of the heat transfer pipes 202, the outer slit parts 211 and
211' are located at the inlet end portion (i.e. central portion
between the centerlines C1-C1 and C-C of the first and the second
heat transfer pipes 202' and 202 in FIG. 6), and a middle slit
parts 212 and 212' are located between the inner slit part 113 and
the outer slit parts 111 and 111'.
[0064] The outer slit parts 211 and 211' and the middle slit parts
212 and 212' are formed in pairs, and the inner slit part 213 is
formed in a unit. First rising portions 211a, 211a', 212a and 212a'
of the outer slit parts 211 and 211' and the middle slit parts 212
and 212' are formed parallel to the direction of air current (A),
and second rising portions 211b, 211b', 212b and 212b' are formed
in parallel to the outer tangential line (m) the heat transfer pipe
202.
[0065] The group of slit parts 214; 215 and 215'; and 216 and 216'
at the air outlet side is constructed in such a manner that the
inner slit part 214 is located adjacent to the centerline C-C of
the heat transfer pipes 202, the outer slit parts 216 and 216' are
located at the air outlet side and the middle slit parts 215 and
215' is located between the fourth row slit part 214 and the outer
slit parts 216 and 216'.
[0066] The inner slit part 214 is formed in a unit. Opposite rising
portions 214a and 214a' are formed in parallel to the direction of
air current (A).
[0067] The outer slit parts 216 and 216' are formed in pairs, being
symmetrical to the outer slit parts 211 and 211' at the inlet side
relative to the centerline C-C of the heat transfer pipes 202.
First rising portions 216a and 216a' arranged parallel to the
direction l of air current (A) and second rising portions 216b and
216b' are arranged parallel to the outer tangential line (m) of the
heat transfer pipe 202.
[0068] The middle slit parts 215 and 215' are formed in pairs,
being asymmetrical to the middle slit parts 212 and 212' at the
inlet side relative to the centerline C-C of the heat transfer
pipes 202. First rising portions 215a and 215a' arranged parallel
to the direction l of air current (A) and second rising portions
215b and 215b' are arranged parallel to the outer tangential line
(m) of the heat transfer pipe 202.
[0069] To reduce the dead zone on the downstream of the heat
transfer pipes 202 which causes a decrease of heat transfer -rate
and an increase of pressure loss, the spacing between the first
rising portions 211a and 211a' of the outer slit parts 211 and 211'
at the air inlet side is formed larger than the spacing between the
first rising portions 212a and 212a' of the middle slit parts 212
and 212', and the second rising portions 211b and 211b'; and 212b
and 212b' of the outer slit parts 211 and 211' and the middle slit
parts 212 and 212' are arranged more adjacently than the prior art
approximately the same distance from the heat transfer pipes
202.
[0070] Likewise, the spacing between the first rising portions 216a
and 216' of the outer slit parts 216 and 216' at the air outlet
side are formed larger than the spacing between the first rising
portions 215a and 215a' of the middle slit parts 215 and 215', and
the second rising portions 216b, 216b', 215b and 215b' of the outer
slit parts 216 and 216' and the middle slit parts 215 and 215' are
arranged adjacently approximately the same distance from the heat
transfer pipes 202.
[0071] At the same time, the first rising portion 216a' of at least
one 216' of the outer slit parts 216 and 216' and the first rising
portion 215a' of at least one 215' of the middle slit parts 215 and
215' are arranged in parallel in the direction l of air current
(A).
[0072] At this time, the middle slit parts 212 and 212' at the air
outlet side and the fifth slit parts 215 and 215' at the air outlet
side are arranged parallel to a diagonal direction relative to the
centerline C-C of the heat transfer pipes 202. That is, the middle
slit parts 215 and 215' at the outlet side of the first and the
second group of slit parts are formed in asymmetrically with the
middle slit parts 212 and 212' at the inlet side relative to the
centerline of the second heat transfer pipes 202.
[0073] Next, in the structure of the shape of the constructed fin,
the structure of heat transfer pipes 202 and 202' arranged in two
rows will be described.
[0074] As illustrated in FIG. 6, the flat fin 200 is divided into
an inlet side row portion and an outlet side row portion with a
center as a boundary therebetween. The first and the second heat
transfer pipes 202 and 202' are inserted through each row portion
perpendicular to the principal direction l of air current (A).
[0075] These heat transfer pipes 202 and 202' are arranged in such
a manner that the inlet side rows and the outlet side rows do not
overlap in the direction of the air current (A).
[0076] Meanwhile the air inlet side rows and the air outlet side
rows are arranged in the approximately same pattern with a phase
difference relative to the central portion between the centerline
C1-C1 of the first heat transfer pipes 202' and the centerline C-C
of the second heat transfer pipes 202.
[0077] That is, the group of slit parts in the air inlet side rows
arranged relative to the centerline C-C of the heat transfer pipe
202 and the group of slit parts in the air outlet side rows
arranged relative to the centerline C1-C1 of the heat transfer pipe
202' are arranged in the same pattern at intervals the same as the
phase difference of the heat transfer pipes 202 and 202', except
for the asymmetrical location of the middle slit parts at the inlet
side and the outlet side.
[0078] As described above, according to the first embodiment of the
present invention, three rows of slit parts are arranged
respectively at the air inlet side and the air outlet side relative
to the centerline of the heat transfer pipes in the first and
second rows at the air inlet end. Each of the inner slit parts at
the air inlet side and the air outlet side is formed in a unit, and
the outer slit parts are formed in pairs. In case of the middle
slit parts arranged between the inner slit parts and the outer slit
parts, each of the middle slit parts at the air inlet side are
formed in a unit, and the middle slit parts at the air outlet side
are formed in pairs. By this construction, the airflow pressure
drop can be decreased, the air volume can be increased, and the
heat transfer rate between the air and the fin surface can be
increased to thus increase the evaporation performance.
[0079] According to the second embodiment of the present invention,
six rows of slit parts are arranged respectively at the air inlet
side and the air outlet side relative to the central portion
between the centerlines of the heat transfer pipes. For example,
each of the inner slit parts at the air outlet side and the air
outlet side are formed in a unit, and the outer slit parts are
formed in pairs. In case of the middle slit parts arranged between
the inner slit parts and the outer slit parts, each of the middle
slit parts at the air inlet side is formed in a unit, and the
middle slit parts at the air outlet side are formed in pairs. By
this construction, the airflow pressure drop can be decreased,
noise can be reduced, and the heat transfer rate between the air
and the fin surface can be increased to thus increase the
evaporation performance.
* * * * *