U.S. patent application number 11/441559 was filed with the patent office on 2007-07-26 for microchannel, flat tube heat exchanger with bent tube configuration.
Invention is credited to Donald Robert Pautler.
Application Number | 20070169922 11/441559 |
Document ID | / |
Family ID | 37969835 |
Filed Date | 2007-07-26 |
United States Patent
Application |
20070169922 |
Kind Code |
A1 |
Pautler; Donald Robert |
July 26, 2007 |
Microchannel, flat tube heat exchanger with bent tube
configuration
Abstract
A heat exchanger assembly includes a first header having an
inlet and a second header having an outlet spaced parallel from
each other. A plurality of tube members having an ultimate strength
(Us) and a width (w), extend between the first header and the
second header. The tube members define a plurality of fluid
passages for the flow of a liquid through the tube members and
between the first and second headers. The tube members extend
through at least one bend having a bend radius (r) in the range of
50.00 mm to straight (.infin.) through angles between 0 and 100
degrees. A plurality of corrugated air fins are brazed between
adjacent tube members. The bends of the tube members satisfy a
bending formula (w/r)Us.ltoreq.30 mega Pascal.
Inventors: |
Pautler; Donald Robert;
(Lockport, NY) |
Correspondence
Address: |
DELPHI TECHNOLOGIES, INC.
M/C 480-410-202
PO BOX 5052
TROY
MI
48007
US
|
Family ID: |
37969835 |
Appl. No.: |
11/441559 |
Filed: |
May 26, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60761467 |
Jan 24, 2006 |
|
|
|
Current U.S.
Class: |
165/153 ;
165/173; 29/890.043 |
Current CPC
Class: |
F28D 2001/0273 20130101;
Y10T 29/49373 20150115; F28D 1/05366 20130101 |
Class at
Publication: |
165/153 ;
165/173; 029/890.043 |
International
Class: |
F28D 1/047 20070101
F28D001/047 |
Claims
1. A heat exchanger assembly for use in residential air
conditioning units comprising; a first header and a second header
spaced parallel from each other, a plurality of tube members
extending between said first header and said second header and
having a width from a first nose to a second nose and defining a
plurality of fluid passages for the flow of a liquid through said
tube members and between said first and second headers, said tube
members extending through at least one bend having a bend radius
(r), said tube members having an ultimate strength (Us), and a
plurality of air fins disposed between adjacent ones of said tube
members for dissipating heat from said tube members, said bends of
said tube members satisfying a bending formula (w/r)Us.ltoreq.30
mega Pascal.
2. An assembly as set forth in claim 1 wherein said bend radius (r)
is in the range of 50.00 mm to straight (.infin.) through angles
between 0 and 100 degrees.
3. An assembly as set forth in claim 2 wherein said width (w) of
said tube members is in the range of 12.00 mm to 27.00 mm.
4. An assembly as set forth in claim 3 wherein said tube members
include two parallel flat sides extending between said
semi-circular first and second noses.
5. An assembly as set forth in claim 4 wherein said plurality of
air fins are corrugated and brazed between two of said parallel
flat sides of adjacent ones of said tube members for dissipating
heat from said tube members.
6. An assembly as set forth in claim 5 wherein said tube members
include an internal wall thickness (t.sub.i) between each of said
passages and the next adjacent one of said passages in the range of
0.15 mm to 0.40 mm.
7. An assembly as set forth in claim 6 wherein said tube members
include an external wall thickness (t.sub.e) between each of said
passages and said flat sides in the range of 0.15 mm to 0.40
mm.
8. An assembly as set forth in claim 7 wherein said tube members
include a nose thickness (t.sub.n) between each of said first and
second noses and the adjacent one of said passages in the range of
0.15 mm to 1.00 mm.
9. An assembly as set forth in claim 8 wherein said passages are
generally round in cross section.
10. An assembly as set forth in claim 9 wherein said passages
include a diameter (d) in the range of 0.50 mm to 1.00 mm.
11. An assembly as set forth in claim 10 wherein said tube members
are aluminum.
12. A heat exchanger assembly for use in residential air
conditioning units comprising; a first header and a second header
spaced parallel from each other, a plurality of tube members
extending between said first header and said second header and
having two parallel flat sides extending between semi-circular
first and second noses spaced a width (w) from said first nose to
said second nose and defining a plurality of fluid passages each
being generally round in cross section for the flow of a liquid
through said tube members and between said first and second
headers, said tube members extending through at least one bend
having a bend radius (r) in the range of 50.00 mm to straight
(.infin.) through angles between 0 and 100 degrees, said tube
members being of aluminum and having an ultimate strength (Us),
said width (w) of said tube members being in the range of 12.00 mm
to 27.00 mm, said tube members having an internal wall thickness
between each of said passages and the next adjacent one of said
passages in the range of 0.15 mm to 0.40 mm, said tube members
having an external wall thickness (t.sub.e) between each of said
passages and said flat sides in the range of 0.15 mm to 0.40 mm,
said tube members having a nose thickness (t.sub.n) between each of
said first and second noses and the adjacent one of said passages
in the range of 0.15 mm to 1.00 mm, said passages having a diameter
(d) in the range of 0.50 mm to 1.00 mm, and a plurality of air fins
being corrugated and brazed between two of said parallel flat sides
of adjacent ones of said tube members for dissipating heat from
said tube members, said bends of said tube members satisfying a
bending formula (w/r) Us.ltoreq.30 mega Pascal.
13. A method for manufacturing a heat exchanger assembly having a
plurality of bent tube members for use in residential air
conditioning units comprising the steps of; preparing a straight
condenser having a plurality of headers spaced parallel from each
other and a plurality of tube members defining a plurality of flow
passages extending between the headers and a plurality of air fins
extending between the tube members, brazing joints between the
headers and the tube members and between the tube members and the
air fins, and bending the straight condenser to at least one
predetermined bend satisfying a bending formula (w/r)Us.ltoreq.30
mega Pascal and wherein w equals a width (w) extending between
semi-circular noses and r equals a bend radius (r) and Us equals
the ultimate strength (Us) of the tube members.
14. A method as set forth in claim 13 wherein the bend radius (r)
is in the range of 50.00 mm to straight (.infin.) through angles
between 0 and 100 degrees.
15. A method as set forth in claim 14 wherein the width (w) is in
the range of 12.00 mm and 27.00 mm.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of provisional
application No. 60/761,467, filed on Jan. 24, 2006.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The subject invention relates to a heat exchanger assembly
for use in residential air conditioning units.
[0004] 2. Description of the Prior Art
[0005] It is known in the prior art how to produce heat exchangers
of the type having round, expanded tubes and flat, non brazed fins
in various bent or non flat configurations, as shown in U.S. Pat.
No. 5,954,125 to Mantegazza et al. These configurations are often
used in outdoor heat exchanger cabinets for residential
applications, and may be fairly easily bent in L, V or U shaped
configurations, in which various face portions remain flat and
joined to other flat face portions across relatively sharp bends of
up to ninety degrees.
[0006] It is also known in the prior art that brazed heat exchanger
construction with flat, microchannel tubes and brazed, corrugated
air fins are inherently more thermally efficient than older,
expanded round tube and non brazed flat fin designs, but have not
found wide acceptance as a replacement for the type of heat
exchanger shown in the Mantegazza patent. One reason for this is
the perceived difficulty or inability in bending relatively wide,
flat microchannel tubes across equivalent bends. One way around
this difficulty is disclosed in U.S. Pat. No. 5,826,649 to Chapp et
al. The Chapp patent avoids the problem by simply orienting the
flat tubes vertically, and allowing them to remain straight and
unbent. The round headers are instead bent into the desired shape,
and oriented at the top and bottom of the core. However not all
header designs will be so amendable to bending, and it may be
desired to leave the headers vertical, straight, and unbent, which
would necessitate either bending the flat tubes, or finding
alternate ways to interconnect the various flat face portions of
the core together.
[0007] It has been proposed to provide an essentially cylindrical
core of two semi circular portions, both bent in a shallow and
continuous curvatures, and joined together by box like headers as
disclosed in U.S. Pat. No. 4,443,921 to Allemandou. No sharp bends
in the tube members are needed to create the semi circular shape of
the core faces.
[0008] Although the prior art shows bends in heat exchanger
assemblies of various configurations, there is a continuing need
for heat exchanger assemblies having more efficient or alternative
bending configurations as compared to the conventional heat
exchanger assemblies.
SUMMARY OF THE INVENTION AND ADVANTAGES
[0009] The invention provides a heat exchanger assembly for use in
residential air conditioning units. The assembly includes a first
header and a second header spaced parallel from each other. A
plurality of tube members extend between the first header and the
second header. The tube members have a width (w) that is measured
from a first nose of the tube member to a second nose of the tube
member. The tube members define a plurality of fluid passages for
the flow of a liquid through the tube members and between the first
and second headers. The tube members have an ultimate strength (Us)
and extend through at least one bend having a bend radius (r). A
plurality of air fins are disposed between adjacent tube members
for dissipating heat from the tube members. The invention is
distinguished by the bends of the tube members satisfying a bending
formula (w/r)Us.ltoreq.30 mega Pascal.
[0010] The subject invention also provides a method of
manufacturing a heat exchanger assembly having a plurality of bent
tube members for use in residential air conditioning units. The
method includes preparing a straight condenser having a plurality
of headers spaced parallel from each other and a plurality of tube
members defining a plurality of flow passages extending between the
headers and a plurality of air fins extending between the tube
members. The method further includes brazing the joints between the
headers and the tube members and between the tube members and the
air fins. The method is distinguished by bending the straight
condenser to at least one predetermined bend satisfying a bending
formula (w/r)Us.ltoreq.30 mega Pascal, wherein w equals a width
extending between semi-circular noses, r equals a bend radius, and
Us equals the ultimate strength of the tube members.
[0011] Accordingly, the invention produces sharp bends of
relatively wide and thin, flat microchannel extruded tube members
with brazed, corrugated air fins.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Other advantages of the present invention will be readily
appreciated, as the same becomes better understood by reference to
the following detailed description when considered in connection
with the accompanying drawings wherein:
[0013] FIG. 1 is perspective view of a heat exchanger embodying the
subject invention;
[0014] FIG. 2 is a cross-sectional view of a tube member taken
along the line 2-2 of FIG. 1; and
[0015] FIG. 3 is top view of a heat exchanger embodying the subject
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Referring to the Figures, wherein like numerals indicate
corresponding parts throughout the several views, a heat exchanger
assembly 20 is generally shown for use in residential air
conditioning units in FIGS. 1-3.
[0017] The assembly 20 comprises a first header 22 and a second
header 24 spaced parallel from each other. The first header 22
includes an inlet 26 and the second header 24 includes an outlet 28
for the flow of a liquid through the assembly 20. Although the
headers 22, 24 are illustrated as trapezoidal in cross-section,
many different configurations may be used, including round and
rectangular. A plurality of tube members 30 generally indicated
extend between the first header 22 and the second header 24. The
tube members 30 have two parallel flat sides 32 that extend between
semi-circular first and second noses 34, 36. The first nose 34 and
the second nose 36 are spaced a width w from each other. The width
w of the tube members 30 is in the range of 12.00 mm to 27.00 mm.
The tube members 30 define a plurality of fluid passages 38 for the
flow of a liquid through the tube members 30 and between the first
and second headers 22, 24. As is well known in the art, the
refrigerant may make multiple passes between the headers 22, 24 by
placing appropriate dividers or baffles in the headers 22, 24. The
passages 38 are generally round in cross section, but may be any
shape known in the art. The passages 38 have a diameter d in the
range of 0.50 mm to 1.00 mm. The liquid will enter the assembly 20
through the inlet 26 of the first header 22, move through the
passages 38 of the tube members 30 to the second header 24, and out
of the assembly 20 through the outlet 28 of the second header
24.
[0018] The tube members 30 extend through at least one bend having
a bend radius r in the range of 50.00 mm to straight (.infin.)
through angles between 0 and 100 degrees. The tube members 30 have
an ultimate strength Us and are typically made of aluminum or
aluminum alloys, but may be of any material known in the art, such
as copper or copper alloys. The ultimate strength Us of the
material being used can be found in several publications that list
various properties of materials. One such publication is "Property
of Aluminum Alloys: Tensile, Creep, and Fatigue Data at High and
Low Temperatures" published by The Aluminum Association and ASM
International.
[0019] The tube members 30 have an internal wall thickness t.sub.i
between each of the passages 38 and the next adjacent one of the
passages 38 in the range of 0.15 mm to 0.40 mm. The tube members 30
have an external wall thickness t.sub.e between each of the
passages 38 and the flat sides 32 of the tube members 30 in the
range of 0.15 mm to 0.40 mm. The tube members 30 have a nose
thickness t.sub.n between each of the first and second noses 34, 36
and the adjacent one of the passages 38 in the range of 0.15 mm to
1.00 mm.
[0020] A plurality of air fins 40 are brazed between two of the
parallel flat sides 32 of adjacent tube members 30 for dissipating
heat from the tube members 30. The air fins 40 are corrugated.
[0021] The subject invention is distinguished by the bends of the
tube members 30 satisfying a bending formula (w/r)Us.ltoreq.30 mega
Pascal. The ratio of the width w of the tube members 30 to the bend
radius r multiplied by the ultimate strength Us of the material
used must be less than 30 mega Pascal for a successful sharp
bend.
[0022] By way of an example we calculate the dimensions of the tube
member 30 with a width w=12.00 mm and a bend radius r=50.00 mm
using the bending formula and the width w and bend radius r ranges
set out above. In addition to width w and bend radius r, for the
bending equation. Again, such a value can be obtained from
"Property of Aluminum Alloys: Tensile, Creep, and Fatigue Data at
High and Low Temperatures" published by The Aluminum Association
and ASM International. For 3003 "0" temper aluminum, the ultimate
strength Us was found to be 110 mega Pascal. When the values are
plugged into the bending formula (12 mm/50 mm)110 mega
Pascal.ltoreq.30 mega Pascal, a value of 26.4 mega Pascal.ltoreq.30
mega Pascal is obtained. The formula is satisfied and the tube
member 30 with these values may be bent.
[0023] The subject invention also provides for a method of
manufacturing a heat exchanger assembly 20 having a plurality of
bent tube members 30 for use in residential air conditioning units.
The method begins with the step of preparing a straight condenser.
The condenser includes a plurality of headers 22, 24 spaced
parallel from each other, a plurality of tube members 30 defining a
plurality of flow passages 38 extending between the headers 22, 24,
and a plurality of air fins 40 extending between the tube members
30. The method proceeds with the step of brazing the joints between
the headers 22, 24 and the tube members 30 and between the tube
members 30 and the air fins 40. The method is distinguished by
bending the straight condenser to at least one predetermined bend
satisfying a bending formula (w/r)Us.ltoreq.30 mega Pascal, wherein
w equals a width w extending between semi-circular noses 34, 36,r
equals a bend radius r, and Us equals the ultimate strength Us of
the tube members 30 material. The method is more specific by
establishing a range for the bend radius r of 50.00 mm to straight
(.infin.) through angles between 0 and 100 degrees and a range for
the width w of 12.00 mm and 27.00 mm.
[0024] Obviously, many modifications and variations of the present
invention are possible in light of the above teachings. The
invention may be practiced otherwise than as specifically described
within the scope of the appended claims.
* * * * *