U.S. patent application number 10/027631 was filed with the patent office on 2003-06-26 for flat tube heat exchanger core with internal fluid supply and suction lines.
Invention is credited to Rasso, Steven J. JR., Wittmann, Joseph E..
Application Number | 20030116310 10/027631 |
Document ID | / |
Family ID | 21838842 |
Filed Date | 2003-06-26 |
United States Patent
Application |
20030116310 |
Kind Code |
A1 |
Wittmann, Joseph E. ; et
al. |
June 26, 2003 |
Flat tube heat exchanger core with internal fluid supply and
suction lines
Abstract
Heat exchanger core comprising flat plate fluid U flows tubes
stacked on one another and operatively connected to one another by
discrete fluid supply and suction lines. These lines extending
through side-by-side tank portions of the tubes to improve
structural integrity of the core and respectively have fluid feed
and exhaust openings communicating with the tanks and sized to
provide even distribution of the heat exchanger fluid to the tubes.
With the supply and suction lines, evenly distributing the heat
exchanger fluid, tank size and capacity is optimized and the
requirement for large capacity deep draw tanks of prior
constructions is eliminated.
Inventors: |
Wittmann, Joseph E.;
(Dayton, OH) ; Rasso, Steven J. JR.; (Bellbrook,
OH) |
Correspondence
Address: |
DAIMLERCHRYSLER INTELLECTUAL CAPITAL CORPORATION
CIMS 483-02-19
800 CHRYSLER DR EAST
AUBURN HILLS
MI
48326-2757
US
|
Family ID: |
21838842 |
Appl. No.: |
10/027631 |
Filed: |
December 21, 2001 |
Current U.S.
Class: |
165/153 ;
165/176 |
Current CPC
Class: |
F28F 9/0273 20130101;
F28D 1/0341 20130101 |
Class at
Publication: |
165/153 ;
165/176 |
International
Class: |
F28D 001/02; F28D
007/06 |
Claims
What is claimed is:
1. A heat exchanger having a plurality of flattened fluid flow
tubes operatively mounted adjacent one another to provide passage
for volatile heat exchanger fluid therethrough, each of said tubes
having a leading edge, a trailing edge and a lower end, said edges
bounding flattened side portions that are laterally spaced from one
another, a divider rib extending in each of said tubes to a
terminal end therein to define separate first and second side flow
sections in each of said tubes and a crossover section at the lower
end thereof for transmitting said heat exchanger fluid from said
first side flow section to said second side flow section, and an
inlet line extending into each of said tubes for feeding heat
exchanger fluid into each of said first side flow section of each
of said tubes and an outlet line extending in each of said tubes
for exhausting heat exchanger fluid from said second side flow
section of each of said tubes.
2. The heat exchanger of claim 1 wherein said fluid inlet line has
fluid flow openings spaced at predetermined intervals along the
length thereof for respectively transmitting heat exchanger fluid
into a first of said side flow sections of each tube, said outlet
line has fluid flow openings spaced at predetermined intervals
along the length thereof for transmitting heat exchanger fluid from
said second side flow sections of each tube into said outlet
line.
3. The heat exchanger of claim 1 wherein said tubes have laterally
extending tank portions formed in side-by-side relationship at the
upper end thereof, each of said tank portions having a laterally
extending neck portion each of said neck portions defining a
laterally oriented opening, and wherein said tubes are closely
received in said openings and are supported by said neck portions
in a side-by-side relationship.
4. The heat exchanger of claim 2 wherein said flow openings in said
pipes are sized so that each tube receives and discharges fluid
substantially at the same fluid flow rate during heat exchanger
operations to optimize the operating efficiency of said heat
exchanger.
5. A heat exchanger having a plurality of flattened fluid flow
tubes operatively arranged adjacent to one another to provide
passage for volatile heat exchanger fluid therethrough, a
connection for interconnecting said tubes so that air can
externally pass between said tubes, each of said tubes having a
leading edge and a trailing edge and flattened side portions that
are laterally spaced from one another, divider rib means in each of
said tubes extending between the walls of said tubes to a terminal
end therein to define first and second discreet side flow sections
in each of said tubes and a crossover section for transmitting said
volatile heat exchanger fluid from one side flow section to the
other side flow section, an elongated inlet line and an elongated
outlet line extending into each of said tubes of said heat
exchanger and out of each of said tubes, said lines having fluid
flow openings therein for transmitting heat exchanger fluid into a
first side flow section of each of said tubes and for transmitting
fluid from said second side flow section each of said tubes.
6. The heat exchanger of claim 5 wherein each flattened tube has
protuberances formed therein extending laterally outwardly from the
plane thereof and wherein said protuberances define tank portions
for each of said tubes, said protuberances further having neck
portions which engage and support said supply and suction
lines.
7. The heat exchanger of claim 5, wherein said tubes are completely
spaced from one another and wherein said tubes are mechanically
connected to one another by said outlet and inlet lines.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to heat exchangers and more
particularly to new and improved multi-tube heat exchanger cores in
which the majority of the tubes are formed by identical flattened
plates operatively joined in an interfacing relationship and in
which discrete fluid supply and suction lines extend though tank
portions of the core and mechanically connect thereto to strengthen
the core.
[0003] 2. Background Art
[0004] Prior to the present invention various compact and
lightweight heat exchanger cores have been designed and developed
for automotive air conditioning and other uses. Many of these prior
units involve the employment of narrow-width refrigerant U-flow
tubes fabricated from mated pairs of thin plates stamped from
aluminum or other suitable sheet metal materials. These tubes are
generally provided with side-by-side tanks, formed by deep-drawn,
laterally-extending bulges or protrusions in each of the plates at
the upper ends thereof. These tanks conduct and distribute the flow
of heat exchanger fluid from a supply into the tubes and exhaust
the fluid from the tubes back into a return. The tubes are brazed
or otherwise operatively connected together when stacked into a
core with thin corrugated air centers secured therebetween. These
cores and their tubes generally include a plurality of variously
configured plates including blocker plates, require extensive
development costs and time to provide a highly efficient unit and
are difficult to build. Moreover, the employment of deep draw tanks
found in many prior plate type units adds to manufacturing costs
because of plate scraping from tears, wall thinning or other
defects particularly occurring in the deep draw tank sections
during plate forming.
SUMMARY OF THE INVENTION
[0005] In the present invention, special internal supply and
suction lines are employed to separately feed and exhaust heat
exchanger fluid to and from each of the tubes of a heat exchanger
unit such as an evaporated or of an air conditioning system so that
the draw depth of the tank section of the tubes can be
substantially reduced. The decrease in the draw depth of the tank
as in this invention optimizes plate stamping since a reduced
amount of material is moved during stamping and production defects
are minimized. In contrast, deep draw tanks of prior units require
displacement of more material by the tooling that may result in
splitting, tearing or thinning of the aluminum materials in the
tank areas. Accordingly, the scrap or rebuild costs associated with
deep draw tanks designs and their attendant torn or thin areas are
effectively eliminated in this invention with new and improved
construction.
[0006] More particularly this invention further involves the use of
elongated tubular supply and suction lines of a suitable metal or
metal alloy that are rigid and pass through or into the reduced
draw tank sections of the core. These lines importantly
mechanically strengthen the core and serve as improved refrigerant
distributors throughout the evaporator. More particularly these
line are holed with fluid transmitting openings that beneficially
insure that there is an even flow of heat exchanger fluid into and
out of each of the tubes for improved operational efficiency. This
function was previously achieved by using special blocker plates to
effect a change in flow direction in a heat exchanger fluid in the
core so that the refrigerant flows to all parts of the evaporator.
Such blocker plates are not needed in this invention.
[0007] The present invention importantly provides a reduction in
complexity and utilizes a minimum number of plate styles or designs
that go into a heat exchanger unit such as an evaporator. This
accordingly simplifies heat exchanger core constructions with
minimized chance for core misbuilds. The number of storage
locations and part handling burden are reduced in this invention
because there are fewer stamped plate designs and no blank plates
used in the heat exchanger.
[0008] It is a feature object and advantage of this invention to
provide a new and improved heat exchanger cores comprising stacked
U-flow heat exchanger tubes formed from an optimal number of
operatively connected and flattened plates and cooperating supply
and suction lines extending internally through tank sections of the
core to improve core strength. The lines are perforated with sized
fluid flow openings at strategic locations to optimize the
distribution of heat exchanger fluids throughout the tubes of the
core for improved operational efficiency.
[0009] These and other features objects and advantages of this
invention will become more apparent from the following description
and drawing in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a pictorial view of a heat exchanger core having a
plurality of flattened tubes conducting heat exchanger fluid from
an inlet to an outlet;
[0011] FIG. 2 is a rear plan view of a plate for making one of the
tubular passes of the heat exchanger of FIG. 1;
[0012] FIG. 3 is a front plan view of the plate of FIG. 2;
[0013] FIG. 4 is an enlarged side view taken along sight lines 4-4
of FIG. 3;
[0014] FIG. 5. is a front view of one of the tubular passes formed
from the joining of the plates of FIGS. 2 and 3;
[0015] FIG. 6 is a top view taken generally along sight lines 6-6
of FIG. 5;
[0016] FIGS. 7, 8 and 9 are cross sectional views respectively
taken along sight lines 7-7, 8-8 and 9-9 of FIG. 5;
[0017] FIG. 10 is a bottom view taken generally along sight lines
10-10 of FIG. 5;
[0018] FIG. 11 is an enlarged view of a portion of the heat
exchanger of FIG. 1; and
[0019] FIG. 12 is a cross sectional view taken along lines 12-12 in
FIG. 11.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0020] Turning now in detail to the drawings there is shown in FIG.
1, one preferred form of this invention comprising a cross-flow
heat exchanger 10 exemplified as an evaporator for an automotive
air conditioning system. The heat exchanger 10 comprises a
plurality of flattened and generally rectilinear, fluid-conducting,
U-flow tubes 12. Some of the tubes in the center of the evaporator
are not illustrated so that interior components are apparent. In
any event, these tubes are stacked in spaced alignment with respect
to one another and have serpentined metallic air centers 14
operatively mounted therebetween to form a heat exchanger core.
Streams of air to be cooled are blown or otherwise forced to flow
through the air centers illustrated by flow arrow A.
[0021] The tubes have side-by-side and laterally-bulging tank
portions 16,18 formed in their upper ends. These tank portions are
formed with axially-aligned, annular openings that receive a pair
of cylindrical, fluid-conducting lines 20, 22 that extend
internally through the tank portions and terminate in stoppered or
blanked terminal ends in the tank portion of the end most tube. As
illustrated in FIG. 1, line 20 feeds the volatile heat exchanger
fluid in its liquid phase from a condenser to the supply side tank
portion 16 of each tube and Line 22 is a suction pipe that exhausts
the heat exchanger fluid in its gaseous phase from the suction side
tank portion 18 of each tube to the compressor of the air
conditioning system.
[0022] Each of the interior tubes of the heat exchanger is
fabricated from a pair of identical mating plates illustrated in
FIGS. 2 and 3 and here identified for purposes of description as
the bottom plate 26' and top plate 26. The top plate 26 is simply a
plate like the bottom plate 26 but turned 180 degrees on the right
hand edge thereof so that the interior face of the bottom plate and
the exterior face of the top plate are shown. The interior faces of
each tube are formed by inner faces of a pair of plates. Each plate
is a flattened aluminum stamping except that the upper ends have
enlarged and side-by-side and outwardly or transversely extending
protuberances 28, 30 and 28', 30' shallow drawn during the stamping
process which cooperate to form the shallow drawn tank portions
16,18. Each protuberance has a transversely oriented opening
therein with a cylindrical neck that extends outwardly of this
opening. Each neck portion terminates in an annular radial flange
32,34 and 32'34'. These neck portions and associated openings are
sized to closely receive and provide support for the elongated
fluid conducting lines 20, 22 that extend through the tank portions
of the unit.
[0023] Moreover each plate has an elongated inwardly indented and
centralized divider rib 36, 36' respectively which mate as shown in
FIG. 8 when the two plates are joined together in an interfacing
and fluid tight relationship and define side flow sections 38 and
40 as well as a lower cross over section 42 at the bottom of the
tube. The tubes provide for the U-flow path for the heat exchanger
fluids from the supply side tank portion 16 to the suction side
tank portion 18. As shown these plates have an indented pattern of
elongated and aligned long and short oval ribs 44, 44' and 46, 46'
respectively that extends longitudinally in the sides of the tubes.
Additionally the plates have obliquely inclined ribs 48, 48' 50,
50' indented therein and semi-spherical indentations 52, 52' in the
cross over section. These ribs and other indentations interfit with
one another to form tortuous or meandering flow paths in the side
flow and cross over sections for the refrigerant coursing
therethrough as illustrated in FIG. 5. Such flow paths ensures an
even distribution of the heat exchanger fluids in the tubes as they
course through the tubes leaving no dry out areas and thereby
improving efficiency of the core.
[0024] Turning in greater particularly to FIGS. 1, 11 and 12, the
supply and suction lines 20 and 22 are respectively provided with
circumfirential fluid flow openings 54, 56 for feeding liquid
refrigerant to the supply side of the tubes and for exhausting
vaporized refrigerant from the suction side of the tubes. The
openings may be formed in annular bands 58, 60 of circumfirentially
spaced openings which respectively align with the tank portions 16,
18 of the tubes. These openings are sized to ensure an even rate of
flow of the heat exchange fluid from line 20 into the supply side
of each of the tubes and from the suction side back of each tube
into the suction line 22.
[0025] If needed the flow capacity of the holes can be tailored by
sizing the holes or by varying the number of holes to reduce
pressure drop and to ensure that each tube processes substantially
the same quantity or different quantities of heat exchange fluid
during evaporator operation. The plates are assembled in an
interfacing relationship in a fixture to form the discrete fluid
tight tubes and air centers are placed between the tubes. The tubes
may be serially installed on the supply and suction lines or
alternatively the supply and suction lines are installed through
the aligned opening in the tubes. In any event, the assembly is
banded or otherwise held and subsequently brazed in an oven at
predetermined temperatures and for a fixed time so that the parts
are fused together in a fluid tight and sturdy arrangement. In
particular the neck portion of the tanks are fused in fluid tight
manner to the supply and suction lines and so that improved
structural support is thereby provided.
[0026] FIG. 11 further illustrates the reduced draw depth of the
plates formed from the blanks. The increased spacing provided
between adjacent tubes provided by their fluid tight connection to
the lines may result in larger air centers and more area for
improved heat management. However, if desired, the tank portions
could be securely joined by brazing their flanges in an interfacing
relationship to further increase unit strength.
[0027] While the above descriptions constitutes preferred
embodiments of the invention, it will be appreciated that the
invention can be modified and varied without departing from the
scope and fair meaning of the accompany claims.
* * * * *