U.S. patent application number 14/846068 was filed with the patent office on 2016-05-26 for heat exchanger assembly.
The applicant listed for this patent is Enterex America LLC. Invention is credited to John A. Kolb.
Application Number | 20160146551 14/846068 |
Document ID | / |
Family ID | 56009865 |
Filed Date | 2016-05-26 |
United States Patent
Application |
20160146551 |
Kind Code |
A1 |
Kolb; John A. |
May 26, 2016 |
HEAT EXCHANGER ASSEMBLY
Abstract
A heat exchanger assembly comprises at least two heat exchanger
cores arranged in parallel flow, each heat exchanger core including
a plurality of tubes, fins between the tubes and opposing headers
sealingly attached at each end of the tubes. A common tank is
positioned between the at least two heat exchanger cores and
connected to a header at one end of each heat exchanger core, and
separate tanks are connected to a header at the other end of each
of the at least two heat exchanger cores. The separate tanks may be
inlet tanks for fluid passing into the heat exchanger assembly and
the common tank may be an outlet tank for fluid passing out of the
heat exchanger assembly, or the flow path may be reversed, with the
common tank being an inlet tank and the separate tanks being outlet
tanks. A method for operating the heat exchanger comprises
providing fluid ports on each of the common tank and the separate
tanks for passage of a fluid into and out of the heat exchanger,
and flowing the fluid between the common tank and the separate
tanks through the at least two heat exchanger cores to cool the
fluid.
Inventors: |
Kolb; John A.; (Westbrook,
CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Enterex America LLC |
Westbrook |
CT |
US |
|
|
Family ID: |
56009865 |
Appl. No.: |
14/846068 |
Filed: |
September 4, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62084620 |
Nov 26, 2014 |
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Current U.S.
Class: |
165/173 |
Current CPC
Class: |
F28F 2009/004 20130101;
F28F 9/0226 20130101; F28D 1/0417 20130101; F28F 9/06 20130101;
F02B 29/0412 20130101; F28D 1/0443 20130101; F28F 9/04 20130101;
F28F 9/0236 20130101 |
International
Class: |
F28F 9/02 20060101
F28F009/02 |
Claims
1. A heat exchanger assembly, comprising: at least two heat
exchanger cores arranged in parallel flow, each heat exchanger core
including a plurality of tubes, fins between the tubes and opposing
headers sealingly attached at each end of the tubes; a common tank
between the at least two heat exchanger cores, the common tank
connected to a header at one end of each heat exchanger core; and
separate tanks connected to a header at the other end of each of
the at least two heat exchanger cores, whereby one of the common
tank or the separate tanks is an outlet tank or tanks for fluid
passing out of the heat exchanger assembly and the other of the
common tank or the separate tanks is an inlet tank or tanks for
fluid passing into the heat exchanger assembly.
2. The heat exchanger assembly of claim 1 wherein the common tank
is centered between the at least two heat exchanger cores.
3. The heat exchanger assembly of claim 1 including a plurality of
heat exchanger cores and wherein there are the same number of heat
exchanger cores on each side of the common tank.
4. The heat exchanger assembly of claim 1 wherein the common tank
and separate tanks are each comprised of steel, the headers are
each comprised of brass, and the heat exchanger cores comprise
brass tubes and copper or copper alloy fins.
5. The heat exchanger assembly of claim 1 including a pair of
opposing side members adapted to provide structural support to the
heat exchanger cores and to substantially eliminate air flow bypass
around the side of the cores.
6. The heat exchanger assembly of claim 1 wherein the heat
exchanger cores are arranged in pairs and further including a core
support member disposed between each pair of heat exchanger cores
and shaped to force entering air to either side of the core support
member and direct air flow to the fins and tubes of the heat
exchanger cores.
7. The heat exchanger assembly of claim 1 wherein each tube has a
tube end sealingly inserted into one of a plurality of openings in
the header to form a resilient tube-to-header joint.
8. A heat exchanger assembly, comprising: at least two heat
exchangers arranged in parallel flow, each heat exchanger including
a plurality of tubes, fins between the tubes, opposing headers
sealingly attached at each end of the tubes, and inlet and outlet
tanks sealingly attached to the headers; a common tank between the
at least two heat exchangers, the common tank connected to a tank
at one end of each heat exchanger; and separate tanks connected to
a tank at the other end of each of the at least two heat
exchangers, whereby one of the common tank or the separate tanks is
an outlet tank or tanks for fluid passing out of the heat exchanger
assembly and the other of the common tank or the separate tanks is
an inlet tank or tanks for fluid passing into the heat exchanger
assembly.
9. The heat exchanger of claim 8 wherein the heat exchangers are
sealingly connected to the common and separate tanks using at least
one hose attached between the tank on one end of each heat
exchanger and the common tank, and the tank on the other end of
each heat exchanger and one of the separate tanks,
respectively.
10. The heat exchanger assembly of claim 8 wherein the common tank
is centered between the at least two heat exchangers.
11. The heat exchanger assembly of claim 8 including a plurality of
heat exchangers and wherein there are the same number of heat
exchangers on each side of the common tank.
12. The heat exchanger assembly of claim 10 wherein the common tank
and separate tanks are each comprised of steel and each of the heat
exchangers comprises a CAB aluminum core, wherein the tanks are
comprised of plastic and the cores are comprised of aluminum tubes,
fins and headers.
13. The heat exchanger assembly of claim 10 including a pair of
opposing side members adapted to provide structural support to the
heat exchangers and to substantially eliminate air flow bypass
around the side of the heat exchangers.
14. The heat exchanger assembly of claim 10 wherein the heat
exchangers are arranged in pairs and further including a support
member disposed between each pair of heat exchangers and shaped to
force entering air to either side of the support member and direct
air flow to the fins and tubes of the heat exchangers.
15. The heat exchanger assembly of claim 10 wherein each tube has a
tube end sealingly inserted into one of a plurality of openings in
the header to form a resilient tube-to-header joint.
16. A method of operating a heat exchanger, comprising the steps
of: providing at least two heat exchanger cores arranged in
parallel flow, each heat exchanger core including a plurality of
tubes, fins between the tubes and opposing headers sealingly
attached at each end of the tubes; providing a common tank between
the at least two heat exchanger cores, the common tank connected to
a header at one end of each heat exchanger core; providing separate
tanks connected to a header at the other end of each of the at
least two heat exchanger cores; providing fluid ports on each of
the common tank and the separate tanks for passage of a fluid into
and out of the heat exchanger, whereby one of the common tank or
the separate tanks is an outlet tank or tanks for fluid passing out
of the heat exchanger and the other of the common tank or the
separate tanks is an inlet tank or tanks for fluid passing into the
heat exchanger; and flowing the fluid between the common tank and
the separate tanks through the at least two heat exchanger cores to
cool the fluid.
17. The method of claim 16 wherein each of the separate tanks
includes an inlet fluid port and the common tank includes an outlet
fluid port, and wherein the step of flowing the fluid between the
common tank and the separate tanks comprises first flowing the
fluid through the separate tank inlet fluid ports, through the at
least two heat exchanger cores, and then through the common tank
outlet fluid port.
18. The method of claim 16 further comprising the step of
connecting an inlet fluid line to a fluid port on one of the common
tank and the separate tanks, and connecting an outlet fluid line to
a fluid port on the other of the common tank and the separate
tanks.
19. A tank for a heat exchanger assembly, the tank positioned
between at least two heat exchanger cores each including a
plurality of tubes, fins between the tubes and opposing headers
sealingly attached at each end of the tubes, the tank connected to
a header at one end of each heat exchanger core and including a
fluid port for passage of a fluid into or out of the heat exchanger
assembly.
20. The tank of claim 19 wherein the at least two heat exchanger
cores are arranged in parallel flow and wherein the fluid is flowed
between the common tank and a pair of opposing separate tanks
connected to a header at the other end of each of the at least two
heat exchanger cores through the at least two heat exchanger cores
to cool the fluid.
Description
RELATED APPLICATIONS
[0001] This application claims priority to U.S. Application No.
62/084,620, filed on Nov. 26, 2014.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to heat exchangers and, more
particularly, to the field of ultra-large air-cooled heat
exchangers used in vehicles or industry, such as engine cooling
radiators of the type used to cool the largest Diesel-electric
generator sets, giant earth-moving haul trucks used in open-pit
mining, and some of the largest Diesel-electric locomotives.
[0004] 2. Description of Related Art
[0005] Engine cooling radiators used with internal combustion
engines in vehicles or industry are often quite large. Such
radiators can be about 9 feet (2.7 m) high by 9 feet (2.7 m) wide
or larger, and are subject to unique problems. Industrial radiators
such as these are typically of copper/brass soldered construction,
wherein solder-coated brass tubes are pushed through holes in a
stack of copper fins, which have been held in the desired spacing
in a grooved book jig, to form a core block. The core block is then
baked in an oven to solder the tubes to the fins. Following this,
the tube ends are inserted into brass headers at each end of the
core block and soldered, to form a core. The height of such a core
is limited by the ability to push long, thin tubes through the
holes in the fins, with 48 in. (1.22 m) being close to a practical
maximum. Similarly, the size of a typical book jig limits core
widths to about 48 in. (1.22 m). Since it is impossible to form
radiator cores with tubes as long as 9 feet (2.7 m), such radiators
are made with a multiple of radiator cores joined together with
core connecting frames.
[0006] To make, for example, a core assembly of overall size 72 in.
(1.83 m) by 72 in. (1.83 m), two 36 in. (91 cm) copper/brass core
blocks are solder connected side-by-side to a single common header
at the top and bottom of the core blocks to produce a first core
assembly. A second core assembly is constructed with two additional
core bocks and two additional headers. The 36-in. (91 cm) high, 72
in. (1.83 m) wide core assemblies are then joined to a connecting
filler frame by bolting, with gaskets between the filler frame and
each core header, the gaskets substantially the same as the gasket
between the radiator tank and the top header of the upper cores.
The headers of the core pairs are bolted, with gaskets, to a steel
inlet tank and outlet tank with a core separator strip between the
side-by-side cores.
[0007] Typically, engine coolant enters the large top tank and
flows down through two upper radiator cores in parallel, then
through the core connecting frame or frames, and finally through
two lower radiator cores in parallel to the bottom outlet tank. The
upper and lower radiator cores form a series flow path, that is,
coolant flows first through the upper cores and then through the
lower cores, with attendant pressure drops. The coolant flow rate
needed to cool such large engines is so high that typically the
radiators are made many more rows of tubes deep than are needed for
cooling, just to be able to pass the high coolant flows without
excessive pressure drop.
[0008] While stationary generator sets are not subject to
transportation shock and vibration, the earth movers and
locomotives certainly are. To survive this environment, radiators
for such service have included resilient tube-to-header joints,
such as Mesabi.RTM. grommeted cores (U.S. Pat. No. 3,391,732) and
General Electric silicone bonded locomotive radiator headers (U.S.
Pat. No. 3,447,603). However, both of these approaches to the
problem are very expensive to implement.
[0009] Moreover, the cooling systems of some locomotives consist of
multiple large radiators which are connected into the system by
valving on an "on demand" basis. As a result, when running in cold
weather on level grade, only two of up to six available radiators
might be connected. Then, when climbing a grade, one or more of the
other radiators would be connected in order to handle the cooling
load. The result is that some radiators would be lying idle at
winter ambient temperatures well below freezing when, suddenly,
they would be shocked with hot coolant around 190 degrees
Fahrenheit. Such a thermal shock would destroy the average radiator
core, therefore resilient tube-to-header joints to absorb the
expansion/contraction of the core tubes, or, alternatively, very
robust construction of tubes and headers, is essential. Again, both
are very expensive.
[0010] Therefore, a need exists for changes to ultra-large
radiators which would allow the assembled cores to be made only as
deep as is necessary for proper cooling without raising pressure
drop, which would allow the cores to be made much less expensively.
A further need exists for a solution to manufacturing ultra-large
radiators which includes resilient tube-to-header joints in a less
expensive manner.
SUMMARY OF THE INVENTION
[0011] Bearing in mind the problems and deficiencies of the prior
art, it is therefore an object of the present invention to provide
an improved heat exchanger assembly for ultra-large air-cooled
radiators wherein the cores are as efficient or even more so than
conventional ultra-large radiator assemblies and can be made less
expensively.
[0012] It is another object of the present invention to provide an
improved heat exchanger assembly whereby the assembled cores are
only as deep as is necessary for proper cooling without raising
pressure drop.
[0013] It is another object of the present invention to provide an
improved heat exchanger assembly whereby the coolant flow path is
reduced by half, thereby reducing coolant pressure drop and
allowing the radiator cores to be made thinner, with fewer of rows
deep, for the same coolant pressure drop.
[0014] A further object of the invention is to provide an improved
heat exchanger assembly for ultra-large radiators wherein the
assembly utilizes automotive-type CAB (controlled atmosphere
brazing) plastic tank aluminum core radiators instead of
conventional copper/brass radiator core construction.
[0015] It is yet another object of the present invention to provide
an improved heat exchanger assembly for ultra-large radiators
wherein the assembly includes resilient tube-to-header joints
required for protection against transportation shock and
vibration.
[0016] Still other objects and advantages of the invention will in
part be obvious and will in part be apparent from the
specification.
[0017] The above and other objects, which will be apparent to those
skilled in the art, are achieved in the present invention which is
directed to, in a first aspect, a heat exchanger assembly
comprising at least two heat exchanger cores arranged in parallel
flow, each heat exchanger core including a plurality of tubes, fins
between the tubes and opposing headers sealingly attached at each
end of the tubes. The assembly comprises a common tank between the
at least two heat exchanger cores, the common tank connected to a
header at one end of each heat exchanger core, and separate tanks
connected to a header at the other end of each of the at least two
heat exchanger cores. The separate tanks may be inlet tanks for
fluid passing into the heat exchanger assembly and the common tank
may be an outlet tank for fluid passing out of the heat exchanger
assembly, or the flow path may be reversed, with the common tank
being an inlet tank and the separate tanks being outlet tanks.
[0018] The common tank may be centered between the at least two
heat exchanger cores, and each of the at least two heat exchanger
cores may have the same dimensions. The heat exchanger assembly may
include a plurality of heat exchanger cores and there may be the
same number of heat exchanger cores on each side of the common
tank.
[0019] Each of the heat exchanger cores may be a copper/brass core,
wherein the common tank and separate tanks are comprised of steel,
the headers are each comprised of brass, and the heat exchanger
cores comprise brass tubes and copper or copper alloy fins.
[0020] The heat exchanger assembly may include a pair of opposing
side members adapted to provide structural support to the heat
exchanger cores and to substantially eliminate air flow bypass
around the side of the cores. The heat exchanger cores may be
arranged in pairs and the heat exchanger assembly may further
include a core support member disposed between each pair of heat
exchanger cores and shaped to force entering air to either side of
the core support member and direct air flow to the fins and tubes
of the heat exchanger cores. The core support member may have a
length corresponding to a length of the heat exchanger cores, and a
width corresponding to a depth of the heat exchanger cores.
[0021] Each tube may have a tube end sealingly inserted into one of
a plurality of openings in the header to form a resilient
tube-to-header joint.
[0022] In another aspect, the present invention is directed to a
heat exchanger assembly, comprising at least two heat exchangers
arranged in parallel flow, each heat exchanger including a
plurality of tubes, fins between the tubes, opposing headers
sealingly attached at each end of the tubes, and inlet and outlet
tanks sealingly attached to the headers. The assembly comprises a
common tank between the at least two heat exchangers, the common
tank connected to a tank at one end of each heat exchanger, and
separate tanks connected to a tank at the other end of each of the
at least two heat exchangers. The separate tanks may be inlet tanks
for fluid passing into the heat exchanger assembly and the common
tank may be an outlet tank for fluid passing out of the heat
exchanger assembly, or the flow path may be reversed, with the
common tank being an inlet tank and the separate tanks being outlet
tanks.
[0023] Each of the heat exchangers may be sealingly connected to
the common and separate tanks using at least one hose attached
between the tank on one end of each heat exchanger and the common
tank, and the tank on the other end of each heat exchanger and one
of the separate tanks, respectively.
[0024] The common tank may be centered between the at least two
heat exchangers, and each of the at least two heat exchangers may
have the same dimensions. The heat exchanger assembly may include a
plurality of heat exchangers and there may be the same number of
heat exchangers on each side of the common tank.
[0025] The common tank and separate tanks may each be comprised of
steel, and each of the heat exchangers may comprise a CAB aluminum
core, wherein the tanks are comprised of plastic, and the cores
comprise aluminum tubes, fins and headers.
[0026] The heat exchanger assembly may include a pair of opposing
side members adapted to provide structural support to the heat
exchangers and to substantially eliminate air flow bypass around
the side of the heat exchangers. The heat exchangers may be
arranged in pairs and the heat exchanger assembly may further
include a support member disposed between each pair of heat
exchangers and shaped to force entering air to either side of the
support member and direct air flow to the fins and tubes of the
heat exchangers. The support member may have a length corresponding
to a length of the heat exchangers, and a width corresponding to a
depth of the heat exchangers.
[0027] Each tube may have a tube end sealingly inserted into one of
a plurality of openings in the header to form a resilient
tube-to-header joint.
[0028] In yet another aspect, the present invention is directed to
a method of operating a heat exchanger. The method comprises the
steps of providing at least two heat exchanger cores arranged in
parallel flow, each heat exchanger core including a plurality of
tubes, fins between the tubes and opposing headers sealingly
attached at each end of the tubes; providing a common tank between
the at least two heat exchanger cores, the common tank connected to
a header at one end of each heat exchanger core; and providing
separate tanks connected to a header at the other end of each of
the at least two heat exchanger cores. The method further comprises
providing fluid ports on each of the common tank and the separate
tanks for passage of a fluid into and out of the heat exchanger,
whereby one of the common tank or the separate tanks is an outlet
tank for fluid passing out of the heat exchanger and the other of
the common tank or the separate tanks is an inlet tank for fluid
passing into the heat exchanger; and flowing the fluid between the
common tank and the separate tanks through the at least two heat
exchanger cores to cool the fluid.
[0029] The method may include providing each of the separate tanks
with an inlet fluid port and the common tank with an outlet fluid
port. In at least one method, the step of flowing the fluid between
the common tank and the separate tanks comprises first flowing the
fluid through the separate tank inlet fluid ports, through the at
least two heat exchanger cores, and then through the common tank
outlet fluid port.
[0030] The method may further comprise the step of connecting an
inlet fluid line to a fluid port on one of the common tank and the
separate tanks, and connecting an outlet fluid line to a fluid port
on the other of the common tank and the separate tanks.
[0031] In still yet another aspect, the present invention is
directed to a tank for a heat exchanger assembly, the tank
positioned between at least two heat exchanger cores each including
a plurality of tubes, fins between the tubes and opposing headers
sealingly attached at each end of the tubes, the tank connected to
a header at one end of each heat exchanger core and including a
fluid port for passage of a fluid into or out of the heat exchanger
assembly. The at least two heat exchanger cores may be arranged in
parallel flow, and the fluid may be flowed between the common tank
and a pair of opposing separate tanks connected to a header at the
other end of each of the at least two heat exchanger cores through
the at least two heat exchanger cores to cool the fluid.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The features of the invention believed to be novel and the
elements characteristic of the invention are set forth with
particularity in the appended claims. The figures are for
illustration purposes only and are not drawn to scale. The
invention itself, however, both as to organization and method of
operation, may best be understood by reference to the detailed
description which follows taken in conjunction with the
accompanying drawings in which:
[0033] FIG. 1 depicts a front elevational view of a typical modular
heat exchanger assembly of the prior art, with a partial cutaway of
a radiator core showing core tubes and cooling fins therebetween
and the direction of coolant flow through the assembly.
[0034] FIG. 2 depicts a front elevational view of one embodiment of
a modular heat exchanger assembly according to the present
invention.
[0035] FIG. 3 depicts a front elevational view of another
embodiment of a modular heat exchanger assembly according to the
present invention, wherein the radiator cores are automotive-type
plastic tank aluminum radiators.
[0036] FIG. 4A depicts a front elevational view of an embodiment of
the present invention wherein the modular heat exchanger assembly
includes a pair of radiator cores.
[0037] FIG. 4B depicts a front elevational view of an embodiment of
the present invention wherein the modular heat exchanger assembly
includes six radiator cores arranged in parallel flow.
[0038] FIG. 5 depicts a cutaway view of a segment of a modular heat
exchanger assembly according to the present invention shown in FIG.
2, showing heat exchanger core fins and tubes secured in headers on
either side of a common tank, with a core support member disposed
between vertically adjacent cores.
[0039] FIG. 6 depicts a cross-sectional view of a segment of an
exemplary header according to an embodiment of the present
invention, wherein each tube-to-header joint is sealed with a
resilient O-ring seal.
DESCRIPTION OF THE EMBODIMENT(S)
[0040] In describing the embodiments of the present invention,
reference will be made herein to FIGS. 1-6 of the drawings in which
like numerals refer to like features of the invention.
[0041] The present invention is directed to a unique assembly of
radiator cores which cut the length of the coolant flow path by
half by having the coolant enter the radiator through two side
inlet tanks and flow horizontally through two (or more) radiator
cores in parallel to a center outlet tank. With the pressure drop
thus reduced, the radiator cores may now be made with fewer rows of
tubes deep, thereby making the cores thinner and less
expensive.
[0042] Certain terminology is used herein for convenience only and
is not to be taken as a limitation of the invention. For example,
words such as "upper," "lower," "left," "right," "horizontal,"
"vertical," "upward," and "downward" merely describe the
configuration shown in the drawings. For purposes of clarity, the
same reference numbers may be used in the drawings to identify
similar elements.
[0043] Referring now to FIG. 1, a typical modular heat exchanger
assembly of the prior art is shown. The modular heat exchanger
includes a plurality of radiator or other heat exchanger cores 10
integrally connected to a plurality of radiator tanks 71. Tanks 71A
and 71C may be a single inlet tank and tanks 71B and 71D may be a
single outlet tank. The cores include parallel vertical tubes 20
and fins 30 between the tubes for increased heat exchange
efficiency, and may be CAB (controlled atmosphere brazing) aluminum
cores. The cores 10 each include a first header 16A at the top end
of the core and a second header 16B at the bottom end of the core.
The modular heat exchanger shown includes four identical cores 10A,
10B, 100, 10D. Vertically adjacent cores 10A, 10B are connected
such that the bottom header 16B of core 10A is sealingly connected
with the top header 16A of core 10B using a filler frame or
connector member 12A. Likewise, vertically adjacent cores 10C, 10D
are connected using a similar filler frame or connector member 12B
secured between bottom header 16B of core 10C and top header 16A of
core 10D. The filler frame or connector member 12A, 12B is an
elongated member having a length approximately equal to the width
of the cores and a width approximately equal to the depth of the
cores. The length of the filler frame is typically greater than the
width. An opening on the top and bottom of filler frame member 12A,
12B permits passage of coolant between the vertically connected
cores, and the filler frame member may include a laterally
outwardly extending top foot or lip and a laterally outwardly
extending bottom foot or lip along the perimeter of each of the
openings to permit the filler frame member to be sealingly secured
with gaskets to the headers of each of the cores. The filler frame
members may be made of any suitable material, for example
steel.
[0044] Each heat exchanger header 16A, 16B, 16C, 16D may be
sealingly connected with a gasket to the filler frame 12 or the
tank 71 in accordance with known methods such as bolting.
[0045] The modular heat exchanger assembly of the prior art further
includes upper radiator or coolant tanks 71A, 71C sealingly
connected to the top header 16A of cores 10A, 10C, respectively,
and lower radiator or coolant tanks 71B, 71D sealingly connected to
the bottom header 16B of cores 10B, 10D, respectively. The tanks 71
each have an inlet/outlet 81 for connection to an internal
combustion engine or other external system. Tanks 71 may be made of
any suitable material, such as steel. Structural side members 40
are provided and are disposed adjacent heat exchanger cores along
the left and right side of the modular heat exchanger and are used
to protect and support the core sides and to substantially
eliminate air flow bypass around the sides of the cores. An
elongated core support member 50 performs a similar task as the
structural side members 40 and extends between upper and lower
headers of the cores.
[0046] Typically, coolant enters the top inlet tanks 71A, 71C and
flows down through the two upper radiator cores 10A, 10C in
parallel, through the filler frame or connector member 12A, 12B,
and finally through the two lower radiator cores 10B, 10D in
parallel to the outlet tanks 71B, 71D. The upper and lower radiator
cores form a series flow path, that is, coolant flows first through
the upper cores and then through the lower cores, with attendant
pressure drops. The coolant flow rate needed to cool such large
engines is so high that typically the radiators are made many more
rows of tubes deep than are needed for cooling, just to be able to
pass the high coolant flows without excessive pressure drop.
[0047] U.S. Pat. No. 8,631,859, entitled "Modular Heat Exchanger",
shows in FIG. 9 a modular heat exchanger assembly made up of CAB
aluminum radiator cores crimped to plastic tanks which are, in
turn, sealingly connected to metal heat exchanger assembly tanks.
It also shows, in FIG. 2, a modular heat exchanger assembly made up
of CAB aluminum radiator cores crimped to plastic heat exchanger
assembly tanks. In both cases, fluid flows in series, with high
attendant pressure drop, first through the upper radiator cores and
then through the lower radiator cores. The modular heat exchanger
assembly of the present invention remedies this deficiency by
reducing the coolant flow path by half, thereby reducing the
coolant pressure drop and allowing the radiator cores to be made
thinner, with fewer rows of tubes deep, for the same coolant
pressure drop. This reduction in core depth will result in
significant manufacturing time and cost savings.
[0048] Referring now to FIG. 2, one embodiment of the modular heat
exchanger assembly of the present invention is shown. The modular
heat exchanger includes at least two radiator or other heat
exchanger cores 100 arranged in parallel flow and integrally
connected to a plurality of radiator tanks 710. For clarity,
cooling air bypass shields and mounting structure have been omitted
in all Figures. The cores include a plurality of parallel tubes 20
and fins 30 between the tubes for increased heat exchange
efficiency, and may be comprised of conventional copper/brass
soldered construction, copper/brass brazed construction
(CuproBraze.RTM.) or CAB (controlled atmosphere brazing) aluminum
construction. As shown in FIG. 2, the cores are comprised of
conventional copper/brass soldered construction, as described
above. The cores 100 each include a first header 160A sealingly
attached at one end of the core tubes and a second header 160B
sealingly attached at the opposite end of the core tubes. Each
header 160A may be an inlet header for passage of coolant into the
modular heat exchanger assembly, and the cores may be positioned
such that coolant will flow through the core tubes in a horizontal
direction between the headers 160A, 160B.
[0049] The modular heat exchanger shown in FIG. 2 includes four
identically-dimensioned cores 100A, 100B, 100C, 100D. Vertically
adjacent cores 100A, 100B are separated by a core support member
500 disposed therebetween. Support member 500 is used to protect
and support the core sides and to substantially eliminate air flow
bypass around the sides of the cores. Likewise, vertically adjacent
cores 100C, 100D are connected using a similar core support member
500 disposed between cores 100C, 100D. The core support member 500
is an elongated member having a length approximately equal to the
length of the cores and a width (in the direction of air flow, into
the Figure) approximately equal to the depth of the cores. The core
support members may be made of any suitable material, for example
steel or aluminum, and are shaped to force entering air to either
side of the core support member and direct air flow to the fins and
tubes of the heat exchanger cores.
[0050] The modular heat exchanger assembly of the present invention
includes separate radiator or coolant tanks 710A, 710C on either
side of the assembly sealingly connected to the first headers 160A
of cores 100A, 100B, 100C, 100D, respectively, and a common tank
710B disposed between and sealingly connected to the second headers
160B of cores 100A, 100B, 100C, 100D, respectively. Common tank
710B may be centered between one or more pairs of horizontally
adjacent cores, as shown in FIG. 2. The tanks 710 each have an
inlet/outlet for connection to an internal combustion engine or
other external system.
[0051] Inlet/outlet fluid ports 810 are provided on each of the
common tank 710B and the separate tanks 701A, 710C for passage of
fluid into and out of the heat exchanger. In an embodiment, the
separate tanks may be inlet tanks for fluid passing into the heat
exchanger assembly and the common tank may be an outlet tank for
fluid passing out of the heat exchanger assembly, or the flow path
may be reversed, with the common tank being an inlet tank and the
separate tanks being outlet tanks. In operation, fluid enters the
assembly through inlet ports in either the common tank or separate
tanks, and the fluid flows between the common tank and the separate
tanks, respectively, through the at least two heat exchanger cores
to cool the fluid. By cutting the length of the coolant flow path
in half over that of the conventional prior art modular assembly,
the coolant pressure drop is reduced, allowing the radiator cores
to be made thinner, with fewer rows of tubes deep, for the same
coolant pressure drop. In certain embodiments, the radiator cores
may be as few as a single row of tubes deep depending on design
requirements.
[0052] As shown in FIG. 2, in at least one embodiment, heated
coolant enters the heat exchanger assembly through inlet fluid
ports 810 in side, opposing coolant tanks 710A, 710C and flows
horizontally in parallel flow through a plurality of tubes in the
horizontally adjacent radiator cores to a center, common outlet
tank 710B which includes an outlet fluid port 810. Coolant does not
flow through core support member 500. It should be understood by
those skilled in the art that in accordance with the objects of the
present invention, in alternate embodiments the direction of
coolant flow may be reversed, e.g. the common tank 710B may be an
inlet tank and the side tanks 710A, 710C may be outlet tanks. Tanks
710 may be made of any suitable material, such as steel. Structural
side members 400 are provided and are disposed adjacent the heat
exchanger cores along the sides of the modular heat exchanger
assembly which do not include coolant tanks and are used to protect
and support the core sides, provide for mounting attachments, and
to substantially eliminate air flow bypass around the sides of the
cores.
[0053] FIG. 5 depicts a cutaway view of a segment of an embodiment
of the modular heat exchanger assembly of the present invention
shown in FIG. 2, showing heat exchanger core fins and tubes secured
in headers on either side of a common tank, with a core support
member disposed between vertically adjacent cores. As shown in FIG.
5, a common tank 710B is centered between horizontally adjacent
cores 100A, 100C and 100B, 100D, respectively. Tank 710B may be an
outlet tank and may include a plurality of integral outlet headers
160B on either side of the tank. A plurality of core tubes 20 are
secured in openings in the header 160B wall, with fins 30
positioned between the tubes for increased heat exchange
efficiency. Coolant flows in a parallel flow between the separate
tanks (not shown) and the common tank 710B through the heat
exchanger cores 100A, 100B, 100C, 100D to cool the coolant.
[0054] As shown in FIG. 5, in at least one embodiment, heated
coolant flows horizontally through the plurality of tubes 20 in
each core in parallel flow, through outlet headers 160B and into
outlet tank 710B before exiting the tank through an outlet fluid
port (not shown). Core support member 500 is disposed between
vertically adjacent cores 100A, 100B and 100C, 100D, respectively,
and is shaped to force entering air to either side of the core
support member and direct air flow to the fins and tubes of the
heat exchanger cores. Coolant does not pass through the core
support member 500.
[0055] The modular assembly of the present invention may be applied
to any type of radiator core construction, including the
conventional large, multi-cored copper/brass core assembly
construction, as shown in FIG. 2. However, such a large core
assembly of copper/brass material is expensive for two reasons.
First, the price of copper and copper-based alloys is expensive
and, second, the manufacturing methods associated with soldered or
brazed copper/brass radiator construction are labor-intensive.
[0056] Automobile and light truck, and some heavy truck, radiators
have long since abandoned costly copper/brass radiator construction
in favor of CAB (controlled atmosphere brazing) aluminum core
construction with plastic tanks. PTA (plastic tank aluminum)
radiators have tabbed aluminum headers which are crimped to a
plastic radiator tank with an elastomeric gasket between. This type
of construction is more automated, requires far less labor, is more
consistent, uses less costly material, and results in a product
which is lighter, stronger and which has demonstrated improved
durability compared to soldered copper/brass. However, the
available CAB furnaces limit core size to not larger than about 48
inches square.
[0057] Referring now to FIG. 3, another embodiment of the modular
heat exchanger assembly of the present invention is shown, wherein
the assembly utilizes modern automotive-type radiators of PTA
(plastic tank aluminum) core construction, as opposed to a
conventional copper/brass core assembly construction typically used
in large industrial or vehicular radiators. FIG. 3 is a front
elevational view of the assembled modular heat exchanger which
includes a plurality of radiators or other heat exchangers 1000 of
PTA core construction integrally connected to a plurality of steel
tanks 7100 and arranged in a similar manner to the embodiment shown
in FIG. 2. For clarity, cooling air bypass shields and mounting
structure have been omitted. The individual inlet/outlet tanks 1600
of each radiator or heat exchanger are connected to side inlet
tanks 7100A, 7100C and common outlet tank 7100B, respectively, by
means of one or more hoses 600. As shown in FIG. 3, radiator tanks
1600A are inlet tanks including headers (not shown) for passage of
fluid into the radiators, whereas radiator tanks 1600B are outlet
tanks and include headers (not shown) for passage of fluid out of
the radiators and into the radiator outlet tanks 7100B. As
described above, in at least one embodiment, coolant enters the
heat exchanger assembly through inlets 810 in side, opposing
coolant tanks 7100A, 7100C, flows through the plurality of hoses
600 into radiator inlet tanks 1600A and then flows horizontally in
parallel flow through a plurality of tubes 20 in horizontally
adjacent radiators or heat exchangers 1000, through radiator outlet
tanks 1600B to a common outlet tank 7100B by way of one or more
hoses 600. Again, it should be understood by those skilled in the
art that in accordance with the objects of the present invention
the direction of coolant flow may be reversed. The headers (not
shown) of each radiator or heat exchanger 1000 may be sealingly
interconnected to the respective inlet/outlet tanks 1600.
[0058] In a typical PTA core construction, the core tubes and fins
are made of aluminum or an aluminum alloy, and may be clad or
coated with braze material, but other metals and alloys may also be
used. The tubes are inserted into, and sealed to, openings in the
walls of an aluminum inlet header and outlet header, respectively,
to make up the core. The headers are connected to, or part of,
plastic inlet and outlet tanks or manifolds and structural side
pieces connect the tanks to complete the heat exchanger. Each of
the tubes has a tube end secured in an opening in the header wall
to form a tube-to-header joint. Oval tubes are typically utilized
for close tube spacing for optimum heat transfer performance of the
heat exchanger, although other tube shapes and cross-sections may
be utilized. The tube-to-header joint is typically brazed to
prevent leakage around the tubes and header.
[0059] Rigid tube-to-header joints pose several problems in the
field of ultra-large heat exchangers, for example, while stationary
generator sets are not subject to transportation shock and
vibration, earth movers and locomotives certainly are. This
transportation shock and/or vibration can lead to failure at the
tube-to-header joint, destroying the radiator core. Moreover, the
cooling systems of some locomotives consist of multiple large
radiators which are connected into the system by valving on an "on
demand" basis. As a result, when running in cold weather on level
grade, only two of up to six available radiators might be
connected. Then, when climbing a grade, one or more of the other
radiators would be connected in order to handle the cooling load.
The result is that some radiators would be lying idle at winter
ambient temperatures well below freezing when, suddenly, they would
be shocked with hot coolant around 190 degrees Fahrenheit. Such a
thermal shock would destroy the average radiator core; therefore,
resilient tube-to-header joints to absorb the expansion/contraction
of the core tubes are essential.
[0060] The modular heat exchanger assembly of the present invention
remedies these deficiencies by, in at least one embodiment,
utilizing a resilient O-ring seal which does not require brazing at
the tube-to-header joint and allows for relative motion between the
tube and header without the build-up of high stresses. FIG. 6
depicts a cross-sectional view of a segment of an exemplary header
according to an embodiment of the present invention, wherein each
tube-to-header joint is sealed with a resilient O-ring seal. As
shown in FIG. 6, in at least one embodiment, each header 160A, 160B
may be comprised of producing by stamping two mating header plates
302, 304. Each header plate includes a plurality of clearance holes
306 for heat exchanger core tubes 20 to pass through, and around
each clearance hole is a continuous depression 308 forming one half
of an O-ring groove 318. O-rings 310 are assembled into these
depressions, and the mating header plate is placed on top of the
lower plate and secured, such as by spot-welding at location 314,
thereby trapping the O-rings in their O-ring grooves 318. As shown
in FIG. 6, the O-rings 310 are assembled in a thin sheet 320 which
is sealed between the mating header plates 302, 304 during assembly
of the header 160A, 160B. In other embodiments, the O-rings may be
assembled to the header plate 302 individually, rather than in one
or more O-ring sheets. The assembled header 160A, 160B is then slid
over the tube ends 112 of the heat exchanger core 100A, 100B, 100C,
100D to its required location, either manually or through
automation. After the header is fitted over the tube ends, the
tubes 20 are then expanded internally by mandrels to provide the
necessary O-ring deformation required to obtain a seal 312. In
service, the resiliency of the O-ring seal 312 allows for expansion
and contraction of the tubes without the build-up of high stresses
at the tube-to-header joint. The connection and method for
connection of such tube-to-header joints are also described in U.S.
patent application Ser. No. 14/844,553 entitled "Heat Exchanger
Tube-to-Header Sealing System", the disclosure of which is hereby
incorporated by reference. The assembled headers 160 may then be
sealingly interconnected to the coolant tanks 710, as shown in FIG.
2. This resilient tube-to-header sealing system may also be used
with the PTA (plastic tank aluminum) heat exchanger construction
shown in FIG. 3.
[0061] The modular heat exchanger assembly according to the present
invention is applicable to many types of ultra-large air-cooled
heat exchangers, such as radiators, charge air coolers and air
cooled oil coolers, for use in vehicles or industry. The assembly
may include any number of heat exchanger cores arranged in parallel
flow. The cores shown in FIGS. 2 and 3 are in a 2.times.2 row and
column arrangement. If each core were 36 in. (0.91 m) high.times.36
in. (0.91 m) wide, the final modular heat exchanger assembly would
be about 72 in. (1.83 m) high (plus the height of the side support
members and center core support member).times.72 in. (1.83 m) wide
(plus the width of the inlet tanks and common outlet tank). It
should be understood by those in the art that additional rows or
columns may be provided, as in 1.times.2 (FIG. 4A), 3.times.2 (FIG.
4B), 4.times.2 or more arrangements to use smaller individual core
sizes, or to create larger modular cores.
[0062] Thus the present invention achieves one or more of the
following advantages. The present invention provides an improved
modular heat exchanger assembly which reduces the coolant flow path
length by half, thereby reducing coolant pressure drop and allowing
the radiator cores to be made thinner, with fewer rows of tubes
deep, for the same coolant pressure drop. The assembly is
applicable to all types of heat exchanger core construction, and
can provide significant cost reductions over conventional practice
by utilizing automotive-type PTA core radiators connected in
parallel to inlet side tanks and a center outlet tank by means of
hoses. The assembly may include resilient tube-to-header joints
which will provide protection against thermal shock in some
locomotive and other radiator applications, at a greatly reduced
cost. The assembly can also be applied to various ultra-large heat
exchangers, such as radiators, charge air coolers and air cooled
oil coolers.
[0063] While the present invention has been particularly described,
in conjunction with specific embodiments, it is evident that many
alternatives, modifications and variations will be apparent to
those skilled in the art in light of the foregoing description. It
is therefore contemplated that the appended claims will embrace any
such alternatives, modifications and variations as falling within
the true scope and spirit of the present invention.
* * * * *