U.S. patent application number 09/897143 was filed with the patent office on 2002-01-10 for heat exchanger with small-diameter refrigerant tubes.
Invention is credited to Jang, Dong Yeon, Lee, Wook Yong, Oh, Sai Kee, Oh, Se Yoon.
Application Number | 20020003035 09/897143 |
Document ID | / |
Family ID | 19676524 |
Filed Date | 2002-01-10 |
United States Patent
Application |
20020003035 |
Kind Code |
A1 |
Oh, Sai Kee ; et
al. |
January 10, 2002 |
Heat exchanger with small-diameter refrigerant tubes
Abstract
A heat exchanger with small-diameter refrigerant tubes is
disclosed. The heat exchanger has a plurality of air guide fins
assembled with each other by one or more vertical rows of
refrigerant tubes passing through the air guide fins. In the heat
exchanger, each of the refrigerant tubes is a small-diameter tube
having an outer diameter of not larger than 6 mm. In addition, four
rows of offset surfaces are vertically formed on each of the air
guide fins at a position between two tubes of each vertical row of
refrigerant tubes through a pressing process such that the four
rows of offset surfaces are arranged along a transverse direction
of the fin. Four rows of vertical slits are each formed by two air
guide openings defined between opposite side edges of each of the
offset surfaces and the land surface of the air guide fin. In the
heat exchanger, the number of the slits is reduced, in addition to
changing the shape and dimension of the slits so as to allow the
slits to be compatible with the small-diameter refrigerant tubes.
The heat exchanger is also reduced in its production cost,
accomplishes the recent trend of compactness, and minimizes its
air-side pressure loss, in addition to accomplishing an improvement
in its heat exchange operational performance due to its enhanced
heat transfer efficiency. This heat exchanger is also improved in
its productivity.
Inventors: |
Oh, Sai Kee; (Seoul, KR)
; Jang, Dong Yeon; (Kyungki-do, KR) ; Oh, Se
Yoon; (Seoul, KR) ; Lee, Wook Yong;
(Kwangmyung-si, KR) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
19676524 |
Appl. No.: |
09/897143 |
Filed: |
July 3, 2001 |
Current U.S.
Class: |
165/151 ;
165/181 |
Current CPC
Class: |
Y10S 165/503 20130101;
F28F 1/325 20130101 |
Class at
Publication: |
165/151 ;
165/181 |
International
Class: |
F28D 001/04; F28F
001/20 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 6, 2000 |
KR |
2000-38505 |
Claims
What is claimed is:
1. A heat exchanger, comprising a plurality of air guide fins
securing a heat exchange surface for allowing heat transfer between
refrigerant and atmospheric air and assembled with each other by
one or more vertical rows of refrigerant tubes passing through the
air guide fins, wherein each of said refrigerant tubes is a
small-diameter tube having an outer diameter of not larger than 6
mm; and four rows of offset surfaces vertically formed on each of
said air guide fins at a position between two tubes of each
vertical row of refrigerant tubes through a pressing process such
that the four rows of offset surfaces are arranged along a
transverse direction of said fin, with four rows of vertical slits
each formed by two air guide openings defined between opposite side
edges of each of said offset surfaces and a land surface of the air
guide fin.
2. The heat exchanger according to claim 1, wherein the entire
offset surfaces are offset from the land surface of the air guide
fin in the same direction.
3. The heat exchanger according to claim 1, wherein the first and
fourth rows of offset surfaces each consist of two spaced unit
offset surfaces, and the second and third rows of offset surfaces
each consist of a single unit offset surface.
4. The heat exchanger according to claim 1, wherein opposite ends
of each of said four rows of offset surfaces are inclined to be
close to a transverse center-line of the offset surfaces in a
direction toward a longitudinal center-line of the offset
surfaces.
5. The heat exchanger according to claim 1, wherein said four rows
of offset surfaces are symmetrically arranged on the basis of a
longitudinal center-line thereof.
6. The heat exchanger according to claim 1, wherein the ends of the
offset surfaces around each of said refrigerant tubes form a trace
circle concentric with the refrigerant tube.
7. The heat exchanger according to claim 6, wherein said trace
circle has a diameter of not larger than two times said outer
diameter of each of said refrigerant tubes.
8. The heat exchanger according to claim 1, wherein each of said
offset surfaces comprises two rising parts at opposite ends
thereof, and a horizontal part extending between said two rising
parts, each of said two rising parts being inclined at a
predetermined angle of inclination relative to said land surface of
the air guide fin.
9. The heat exchanger according to claim 1, wherein the fourth row
of offset surfaces positioned around an outside edge of the air
guide fin is spaced apart from said outside edge by a gap of 0.5 mm
or more.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a heat exchanger with
small-diameter refrigerant tubes and, more particularly, to a heat
exchanger designed such that the number, shape and dimension of
vertical slits formed on its air guide fins are optimally designed
to be compatible with the small-diameter refrigerant tubes.
[0003] 2. Description of the Prior Art
[0004] FIG. 1 is a perspective view of a conventional heat
exchanger. FIG. 2 is a perspective view of a conventional air guide
fin for such heat exchangers. FIG. 3 is a sectional view of the
conventional air guide fin taken along the line A-A of FIG. 2.
[0005] As shown in FIG. 1, the conventional heat exchanger
comprises a plurality of refrigerant tubes 1 and a plurality of air
guide fins 3. The refrigerant tubes 1 form a refrigerant passage of
the heat exchanger, while the air guide fins 3 are vertically
arranged at regular intervals, with the linear parts of the
refrigerant tubes 1 passing through the fins 3. The air guide fins
3 secure the heat exchange surface for allowing heat transfer
between refrigerant and atmospheric air, and improve heat exchange
efficiency of the heat exchanger.
[0006] In the conventional heat exchanger, the entire refrigerant
tubes 1 are arranged relative to the air guide fins 3 to form two
vertical rows of tubes: left- and right-hand vertical rows of tubes
1a and 1b as best seen in FIG. 1. Each of the air guide fins 3 thus
has two vertical rows of tube-fitting openings 20 for allowing an
installation of the tubes 1a and 1b.
[0007] As shown in FIGS. 2 and 3, each of the air guide fins 3 is
typically provided with a plurality of vertical slits 10 for
allowing air to pass through and enhancing the heat exchange
efficiency of the heat exchanger.
[0008] In order to form the slits 10 on each air guide fin 3, the
fin 3 is pressed at regularly spaced positions to form a plurality
of offset surfaces 10a such that the offset surfaces 10a are
alternately offset in opposite directions as best seen in FIG. 3.
Two air guide openings are thus formed between opposite side edges
of each offset surface 10a and the land surface of the fin 3, and
allow air to smoothly pass through to improve heat exchange effect
of the heat exchanger.
[0009] In a detailed description with reference to FIGS. 2 and 3, a
set of vertical slits 10 are each vertically formed on the fin 3 at
a position between two tube-fitting openings 20 of each vertical
row of openings 20 through a pressing process. In such a case, six
rows of vertical slits 10 are arranged in a transverse direction of
the fin 3 at a position between the two tube-fitting openings 20.
The slits 10 are formed by the air guide openings, each of which is
defined between opposite side edges of each of the offset surfaces
loa and the land surface of the air guide fin 3.
[0010] Of the six rows of vertical slits 10, the first, third and
fifth rows of slits 11, 13 and 15 are formed by the upward offset
surfaces 11a, 13a and 15a, while the second, fourth and sixth rows
of slits 12, 14 and 16 are formed by the downward offset surfaces
12a, 14a and 16a. In such a case, the terms "upward offset" and
"downward offset" are defined from FIG. 3 for ease of description.
The first row of slits 11 comprise three unit slits vertically
spaced apart from each other, while the second and sixth rows of
slits 12 and 16 each comprise two unit slits vertically spaced
apart from each other.
[0011] When the slits 10 are formed on each of the air guide fins 3
as described above, the slits 10 reduce the thickness of the
thermal boundary layer inside the atmospheric air flowing along the
fins 3, thus increasing the average heat transfer coefficient of
air, and improving heat exchange operational performance of the
heat exchanger.
[0012] The conventional heat exchanger is designed to use
refrigerant tubes 1 having an outer diameter of 7 mm or 9.52 mm. In
recent years, it is desired to reduce the outer diameter of the
refrigerant tubes 1 in an effort to accomplish a preferable
reduction in both the production cost and air-side pressure loss of
heat exchangers. The refrigerant tubes 1 having such a reduced
outer diameter are so-called "small-diameter refrigerant tubes" in
the specification.
[0013] When a heat exchanger uses a plurality of small-diameter
refrigerant tubes having a reduced outer diameter in place of
conventional refrigerant tubes 1 having an outer diameter of 7 mm
or 9.52 mm, it is necessary to optimally design the arrangement and
shape of both the air guide fins 3 and the slits 10 so as to allow
the fins 3 and the slits 10 to be compatible with the
small-diameter tubes 1.
[0014] When a heat exchanger is fabricated using the small-diameter
refrigerant tubes 1 and the air guide fins 3 without changing the
arrangement and shape of the fins 3, it is almost impossible to
form the slits 10 on the fins 3 since the widths of the slits 10
are extremely reduced as the width of the fins 3 is reduced due to
the reduced outer diameter of the refrigerant tubes 1.
[0015] In the case of using such small-diameter refrigerant tubes 1
in a heat exchanger, the heat exchange efficiency of the air guide
fins 3 may be deteriorated since the heat exchange surface area of
each fin 3 is reduced due to a reduction in the width of the fin 3.
In the prior art, such deterioration in the heat exchange
efficiency of the fins 3 may be overcome by increasing the number
of the air guide fins 3 per unit length of the refrigerant tubes 1
to compensate for the reduction in the heat exchange surface area
of the fins 3. However, when a plurality of slits having the same
arrangement and shape as those of the conventional slits 10 are
formed on such fins 3, the air-side pressure loss of the heat
exchanger is extremely increased to undesirably eliminate the
advantages expected from the use of the small-diameter tubes as the
refrigerant tubes.
[0016] That is, when a heat exchanger is fabricated using such
small-diameter refrigerant tubes 1 while densely arranging the air
guide fins 3 each having the six rows of vertical slits 10 in a
conventional manner, the fins 3 undesirably increase resistance
against air to overload a blower fan, thus damaging or breaking the
blower fan.
[0017] Therefore, it is necessary to propose an air guide fin,
which is preferably used in a heat exchanger having small-diameter
refrigerant tubes, and of which the slits are appropriately
arranged, shaped and sized to be compatible with the small-diameter
refrigerant tubes.
SUMMARY OF THE INVENTION
[0018] Accordingly, the present invention has been made keeping in
mind the above problems occurring in the prior art, and an object
of the present invention is to provide a heat exchanger with
small-diameter refrigerant tubes, of which the number, shape and
dimension of vertical slits formed on the air guide fins are
optimally designed to be compatible with the small-diameter
refrigerant tubes, and which thus minimizes its airside pressure
loss, in addition to accomplishing an improvement in the heat
transfer efficiency of the fins.
[0019] In order to accomplish the above object, the present
invention provides a heat exchanger, comprising a plurality of air
guide fins securing a heat exchange surface for allowing heat
transfer between refrigerant and atmospheric air and assembled with
each other by one or more vertical rows of refrigerant tubes
passing through the air guide fins, wherein each of said
refrigerant tubes is a small-diameter tube having an outer diameter
of not larger than 6 mm; and four rows of offset surfaces
vertically formed on each of said air guide fins at a position
between two tubes of each vertical row of refrigerant tubes through
a pressing process such that the four rows of offset surfaces are
arranged along a transverse direction of said fin, with four rows
of vertical slits each formed by two air guide openings defined
between opposite side edges of each of said offset surfaces and the
land surface of the air guide fin.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The above and other objects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0021] FIG. 1 is a perspective view of a conventional heat
exchanger;
[0022] FIG. 2 is a perspective view of a conventional air guide fin
for such heat exchangers;
[0023] FIG. 3 is a sectional view of the conventional air guide fin
taken along the line A-A of FIG. 2;
[0024] FIG. 4 is a plan view of an air guide fin included in a heat
exchanger with small-diameter refrigerant tubes in accordance with
the preferred embodiment of the present invention;
[0025] FIG. 5 is a sectional view of the air guide f in taken along
the line B-B of FIG. 4;
[0026] FIG. 6 is an enlarged plan view of the air guide f in of
this invention;
[0027] FIG. 7 is a sectional view of the air guide fin taken along
the line C-C of FIG. 4;
[0028] FIG. 8 is a sectional view of the air guide fin taken along
the line D-D of FIG. 4; and
[0029] FIG. 9 is a plan view of an air guide fin having two rows of
small-diameter refrigerant tubes in accordance with the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0030] Reference now should be made to the drawings, in which the
same reference numerals are used throughout the different drawings
to designate the same or similar components.
[0031] FIG. 4 is a plan view of an air guide fin included in a heat
exchanger with small-diameter refrigerant tubes in accordance with
the preferred embodiment of the present invention. FIG. 5 is a
sectional view of the air guide fin taken along the line B-B of
FIG. 4. FIG. 6 is an enlarged plan view of the air guide fin of
this invention. FIG. 7 is a sectional view of the air guide fin
taken along the line C-C of FIG. 4. FIG. 8 is a sectional view of
the air guide fin taken along the line D-D of FIG. 4. FIG. 9 is a
plan view of an air guide fin having two rows of small-diameter
refrigerant tubes according to this invention.
[0032] As shown in FIGS. 4 to 6, the heat exchanger according to
the present invention comprises a plurality of vertical rows of
refrigerant tubes 51 and a plurality of air guide fins 53. The
refrigerant tubes 51 form a refrigerant passage of the heat
exchanger, while the air guide fins 53 are vertically arranged at
regular intervals, with the linear parts of the refrigerant tubes
51 passing through the fins 53. The air guide fins 53 secure the
heat exchange surface for allowing heat transfer between
refrigerant and atmospheric air, and improve heat exchange
efficiency of the heat exchanger. In the heat exchanger of this
invention, each of the refrigerant tubes 51 is a small-diameter
tube having an outer diameter of not larger than 6 mm. In addition,
four rows of vertical slits 60 are formed on each of the air guide
fins 53 at a position between two tubes of each vertical row of
refrigerant tubes 51 such that the slits 60 are arranged along a
transverse direction of the fin 53.
[0033] The slits 60 are formed as follows. That is, four rows of
offset surfaces 70 are vertically formed on each of the air guide
fins 53 at a position between two tubes of each vertical row of
refrigerant tubes 51 through a pressing process such that the four
rows of offset surfaces 70 are arranged along a transverse
direction of the fin 53. The four rows of vertical slits 60 are
each formed by two air guide openings defined between opposite side
edges of each of the offset surfaces 70 and the land surface of the
air guide fin 53. For example, the first row of slits 61 are formed
by two air guide openings 61a and 61b defined between the opposite
side edges of the offset surface 71 and the land surface of the air
guide fin 53 as best seen in FIG. 5. Atmospheric air flow around
the fins 53 under the guide of the slits 60, and so heat exchange
effect of the heat exchanger is enhanced. Of the four rows of
offset surfaces 70, the first and fourth rows of offset surfaces 71
and 74 each consist of two spaced unit offset surfaces, while the
second and third rows of offset surfaces 72 and 73 each consist of
a single unit offset surface.
[0034] In the present invention, the entire offset surfaces 70
having the slits 60 are offset from the land surface of the air
guide fin 53 in the same direction. The unidirectionally offset
structure of the surfaces 70 is caused by the fact that it is
almost impossible to provide sufficient gaps for effectively
forming oppositely offset surfaces between the fins 53 since the
fins 53 in the heat exchanger having the small-diameter tubes 51
are densely arranged to leave narrow gaps of a small pitch between
them due to the reduced diameter of the tubes 51.
[0035] As shown in FIG. 6, the outside end of each of the unit
offset surfaces 71a, 71b, 74a and 74b of the first and fourth rows
of offset surfaces 71 and 74 forming the slits 61 and 64 is
inclined to be close to a transverse center-line "CL1" of the
offset surfaces 70 in a direction toward a longitudinal center-line
"CL2" of the offset surfaces 70.
[0036] In the preferred embodiment of this invention, the unit
offset surfaces 71a, 71b, 74a and 74b are inclined only at their
outside ends, but are horizontal at their inside ends, thus forming
trapezoidal profiles when seeing them in a plan view as shown in
FIG. 6. However, it should be understood that the unit offset
surfaces 71a, 71b, 74a and 74b may be inclined at their inside and
outside ends to form parallelogrammic profiles.
[0037] The opposite ends of each of the second and third offset
surfaces 72 and 73 forming the slits 62 and 63 are inclined to be
close to the transverse center-line "CL1" in the direction toward
the longitudinal center-line "CL2", and so the second and third
offset surfaces 72 and 73 thus form equiangular trapezoidal
profiles. The four rows of offset surfaces 70 forming the slits 60
are symmetrically arranged on the basis of the longitudinal
center-line "CL2".
[0038] In addition, the ends of the offset surfaces 70 with the
slits 60 around each of the refrigerant tubes 51 form a trace
circle "C", which is concentric with the refrigerant tube 51 and
has a diameter of not larger than two times the outer diameter of
each of the refrigerant tubes 51.
[0039] When the offset surfaces 70 around each of the refrigerant
tubes 51 are designed to form such a trace circle "C", it is
possible to more effectively guide air to the outer surfaces of the
refrigerant tubes 51, thus more effectively promoting heat transfer
between the air and the sidewalls of the tubes 51.
[0040] In addition, when the diameter of the trace circle "C" is
limited to be not larger than two times the outer diameter of the
refrigerant tube 51, it is possible to maintain appropriate gaps
between the ends of the slits 60 and the outer surfaces of the
tubes 51, in addition to securing desired sufficient lengths of the
slits 60.
[0041] As shown in FIGS. 7 and 8, each of the offset surfaces 70
with the slits 60 comprises two rising parts 71a' and 71b', 72',
73' or 74a' and 74b' extending from the land surface of the fin 53,
and a horizontal part 71a, 71b, 72, 73, 74a or 74b extending
between the two rising parts. In such a case, the horizontal parts
71a, 71b, 72, 73, 74a and 74b of the offset surfaces 70 each form a
desired slit 61, 62, 63 and 64 between it and the land surface of
the fin 53. Each of the two rising parts 71a' and 71b', 72', 73' or
74a' and 74b' is inclined at a predetermined angle of inclination
relative to the land surface of the air guide fin 53 for
accomplishing smooth flow of air in the slits 60.
[0042] In addition, the fourth row of offset surfaces 74 positioned
at the outermost edge of the slit arrangement are spaced apart from
the outside edge of the air guide fin 53 by a gap "Lt" of 0.5 mm or
more in an effort to allow a precise formation of the offset
surfaces 70 and the slits 60 and protect a press machine during a
process of forming the offset surfaces 70 and the slits 60.
[0043] The four rows of offset surfaces 70 have the same width
"Ws", and are arranged at regular intervals.
[0044] In the heat exchanger of this invention, it is preferable to
arrange two vertical rows of refrigerant tubes 51 on the air guide
tubes 53.
[0045] When the two vertical rows of ref rigerant tubes 51 are
arranged on the air guide tubes 53 as described above, it is
preferable to form a zigzag arrangement of the tubes 51.
[0046] As described above, the present invention provides a heat
exchanger with small-diameter refrigerant tubes. In the heat
exchanger, the number of the vertical slits formed on each air
guide fin is reduced, in addition to changing the shape and
dimension of the slits so as to allow the slits to be compatible
with the small-diameter refrigerant tubes. Therefore, the air guide
fins of the heat exchanger are optimally compatible with the
small-diameter refrigerant tubes. The heat exchanger is thus
reduced in its production cost, accomplishes the recent trend of
compactness, and minimizes its air-side pressure loss, in addition
to accomplishing an improvement in its heat exchange operational
performance due to its enhanced heat transfer efficiency. This heat
exchanger is also improved in its productivity.
[0047] Although a preferred embodiment of the present invention has
been described for illustrative purposes, those skilled in the art
will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
* * * * *