METHOD FOR MANUFACTURING A MULTIPLE MANIFOLD ASSEMBLY
HAVING INTERNAL COMMUNICATION PORTS
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to multiple tube bank heat exchangers and,
more particularly, to the manufacture of a multiple manifold assembly having internal
communication ports between manifolds.
[0002] Heat exchangers have long been used as evaporators and condensers in
heating, ventilating, air conditioning and refrigeration (HVACR) applications. Historically,
these heat exchangers have been round tube and plate fin (RTPF) heat exchangers. However,
all aluminum flattened tube serpentine fin heat exchangers are finding increasingly wider use
in industry, including the HVACR industry, due to their compactness, thermal-hydraulic
performance, structural rigidity, lower weight and reduced refrigerant charge, in comparison
to conventional RTPF heat exchangers. Flattened tubes commonly used in HVACR
applications typically have an interior subdivided into a plurality of parallel flow channels.
Such flattened tubes are commonly referred to in the art as multi-channel tubes, mini-channel
tubes or micro-channel tubes.
[0003] A typical flattened tube serpentine fin heat exchanger includes a first
manifold, a second manifold, and a single tube bank formed of a plurality of longitudinally
extending flattened heat exchange tubes disposed in spaced parallel relationship and
extending between the first manifold and the second manifold. The first manifold, second
manifold and tube bank assembly is commonly referred to in the heat exchanger art as a slab.
Additionally, a plurality of fins are disposed between the neighboring pairs of heat exchange
tubes for increasing heat transfer between a fluid, commonly air in HVACR applications,
flowing over the outside surface of the flattened tubes and along the fin surfaces and a fluid,
commonly refrigerant in HVACR applications, flowing inside the flattened tubes. Such
single tube bank heat exchangers, also known as single slab heat exchangers, have a pure
cross-flow configuration.
[0004] Double bank flattened tube and serpentine fin heat exchangers are also known
in the art. Conventional double bank flattened tube and serpentine fin heat exchangers are
typically formed of two conventional fin and tube slabs, one spaced behind the other, with
fluid communication between the manifolds accomplished through external U-bends or
interconnecting piping. To connect the two slabs in fluid flow communication in other than
a parallel cross-flow arrangement requires complex external piping. For example, U.S.
Patent 6,964,296 B2 and U.S. Patent Application Publication 2009/0025914 Al disclose
embodiments of double bank, multichannel flattened tube heat exchanger.
SUMMARY OF THE INVENTION
[0005] In an aspect, a method is provided for manufacturing a manifold assembly
with internal fluid communication between a first manifold defining a first fluid chamber and
a second manifold defining a second fluid chamber of the manifold assembly, the first
manifold and the second manifold joined in parallel relationship along a longitudinally
extending interface between a wall of the first manifold and a wall of the second manifold.
The method includes: forming a first access port in a wall of one of the first manifold and the
second manifold diametrically opposite the interface; forming a first fluid communication
port extending through a wall of the first manifold and a wall of the second manifold at the
interface and defining a first fluid passage between the first and second fluid chambers; and
sealingly plugging the access port.
[0006] The method may further include: forming at least one additional access port
spaced longitudinally from the first access port; forming at least one additional fluid
communication port extending through the wall of the first manifold and the wall of the
second manifold, at the interface and defining an additional fluid passage between the first
and second fluid chambers spaced longitudinally from the first fluid passage; and sealingly
plugging the at least one additional access port.
[0007] The method may further include forming the manifold assembly as an integral
manifold assembly by an extrusion process.
[0008] The method may include forming the access port and fluid communication
port by a drilling operation. The method may include first forming the access port by a
punching operation and thereafter forming the fluid communication port by a drilling
operation. The method may include first forming the access port by a first punching
operation and thereafter forming the fluid communication port by a second punching
operation.
[0009] Sealingly plugging the access port may comprise inserting a plug in the access
port in a force fit relationship with the manifold in which the first hole is formed and brazing
the inserted plug to the manifold in which the access port is formed. The inserted plug
comprises an end cap and a shaft extending from the end cap into the access port and the end
cap abutting an external surface of the manifold in which the access port is formed. The
method may include brazing the end cap to the external surface of the manifold in which the
access port is formed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] For further understanding of the disclosure, reference will be made to the
following detailed description which is to be read in connection with the accompanying
drawing, where:
[0011] FIG. 1 is a diagrammatic illustration of an embodiment of a multiple tube
bank, flattened tube finned heat exchanger;
[0012] FIG. 2 is a diagrammatic plan view taken along line 2-2 of FIG. 1;
[0013] FIG. 3 is a sectioned plan view of the tube to manifold connection region 3-3
of FIG. 2;
[0014] FIGs. 4A-4D are perspective views, in section, illustrating a method of
forming manifold-to-manifold fluid flow passages in the dual-barrel embodiment of the
integral manifold assembly of FIG. 3;
[0015] FIGs. 5A-5D are cross-sectional views of an extruded triple barrel
embodiment of an integral manifold assembly illustrating a method of forming manifold -to -
manifold fluid flow passages therein; and
[0016] FIG. 6 is a sectioned side elevation view of another embodiment of a triple
barrel integral manifold assembly.
DETAILED DESCRIPTION
[0017] An exemplary embodiment of a multiple bank flattened tube finned heat
exchanger unit, generally designated 10, is depicted in perspective illustration in FIG. 1. As
depicted therein, the multiple bank flattened tube finned heat exchanger 10 includes a first
tube bank 100 and a second tube bank 200 that is disposed behind the first tube bank 100,
that is downstream with respect to air flow, A, through the heat exchanger. The first tube
bank 100 may also be referred to herein as the front heat exchanger slab 100 and the second
tube bank 200 may also be referred to herein as the rear heat exchanger slab 200.
[0018] The first tube bank 100 includes a first manifold 102, a second manifold 104
spaced apart from the first manifold 102, and a plurality of heat exchange tube segments 106,
including at least a first and a second tube segment, extending longitudinally in spaced
parallel relationship between and connecting the first manifold 102 and the second manifold
104 in fluid communication. The second tube bank 200 includes a first manifold 202, a
second manifold 204 spaced apart from the first manifold 202, and a plurality of heat
exchange tube segments 206, including at least a first and a second tube segment, extending
longitudinally in spaced parallel relationship between and connecting the first manifold 202
and the second manifold 204 in fluid communication. Each tube bank 100, 200 may further
include "dummy" guard tubes extending between its first and second manifolds at the top of
the tube bank and at the bottom of the tube bank. These "dummy" guard tubes do not convey
refrigerant flow, but add structural support to the tube bank and protect the uppermost and
lowermost fins.
[0019] Referring now to FIG. 2 also, each of the heat exchange tube segments 106,
206 comprises a flattened heat exchange tube having a leading edge 108, 208, a trailing edge
110, 210, an upper surface and a lower surface. The leading edge 108, 208 of each heat
exchange tube segment 106, 206 is upstream of its respective trailing edge 110, 210 with
respect to airflow through the heat exchanger 10. The interior flow passage of each of the
heat exchange tube segments 106, 206 of the first and second tube banks 100, 200,
respectively, may be divided by interior walls into a plurality of discrete flow channels that
extend longitudinally the length of the tube from an inlet end of the tube to an outlet end of
the tube and establish fluid communication between the respective fluid chambers of the
manifolds 102, 104 of the first tube bank 100 and respective fluid chambers of the manifolds
202, 204 of the second tube bank 200.
[0020] Referring again in particular to FIG. 1, the flattened tube finned heat
exchanger 10 may further include a plurality of folded fins 20. Each folded fin 20 is formed
of a single continuous strip of fin material tightly folded in a ribbon-like serpentine fashion
thereby providing a plurality of closely spaced fins that extend generally orthogonal to the
flattened heat exchange tubes 106, 206. Heat exchange between the refrigerant flow, R, and
air flow, A, occurs through the outside surfaces of the heat exchange tube segments 106, 206
and also through the heat exchange surface of the fins of the folded fin 20. In the depicted
embodiment, the depth of each of the ribbon-like folded fin 20 extends at least from the
leading edge 108 of the first tube bank 100 to the trailing edge of 210 of the second bank 200.
[0021] The multiple bank, flattened tube heat exchange unit 10 disclosed herein is
depicted in a cross-counterflow arrangement wherein refrigerant (labeled "R") from a
refrigerant circuit (not shown) of a refrigerant vapor compression system (not shown) passes
through the manifolds and heat exchange tube segments of the tube banks 100, 200, in a
manner to be described in further detail hereinafter, in heat exchange relationship with a
cooling media, most commonly ambient air, flowing through the airside of the heat
exchanger 10 in the direction indicated by the arrow labeled "A" that passes over the outside
surfaces of the heat exchange tube segments 106, 206 and the surfaces of the fins 22 of the
folded fins 20. The air flow first passes transversely across the upper and lower horizontal
surfaces of the heat exchange tube segments 106 of the first tube bank, and then passes
transversely across the upper and lower horizontal surfaces of the heat exchange tube
segments 206 of the second tube bank 200. The refrigerant passes in cross-counterflow
arrangement to the airflow, in that the refrigerant flow passes first through the second tube
bank 200 and then through the first tube bank 100. The multiple tube bank, flattened tube
finned heat exchanger 10 having a cross-counterflow circuit arrangement yields superior heat
exchange performance, as compared to the crossflow or cross-parallel flow circuit
arrangements, as well as allows for flexibility to manage the refrigerant side pressure drop via
implementation of tubes of various widths within the first tube bank 100 and the second tube
bank 200.
[0022] The second manifolds 104 and 204 are longitudinally elongated, tubular
manifolds disposed in side-by-by side parallel relationship and connected together along a
longitudinally extending interface by a web extending between the outer walls of the parallel
second manifolds to form a multiple barrel (i.e. multiple assembly) manifold assembly 220.
Depending upon the desired spacing, if any, to be provided, the parallel manifolds 104 and
204 may be disposed with their respective outer walls abutting or with their respective outer
walls in spaced relationship. In an embodiment, the manifold assembly 220 may be formed
as an integral one-piece unit by an extrusion process. In an embodiment, the manifold
assembly 220 may be fabricated by bonding two or more manifolds together, for example, by
welding or brazing, with the weld or braze joint forming the connecting web.
[0023] Referring now to FIG. 3, the neighboring second manifolds 104 and 204 of the
depicted dual barrel manifold assembly 220 are connected in fluid flow communication by at
least one fluid flow passage 222 such that refrigerant may flow from the interior fluid
chamber 216 of the second manifold 204 of the second tube bank 200 into the interior fluid
chamber 116 of the second manifold 104 of the first tube bank 100. Typically, a plurality of
fluid flow passages 222 are provided between the second manifolds 104 and 204 at
longitudinally space intervals. It is understood, however, that manifolds 104 and 204 may
have multiple internal chambers (depending on a number of refrigerant passes), and only
some of the adjacent chambers may need to be connected by the internal fluid flow passages
222 to form the cross-counterflow configuration between refrigerant flowing inside the tubes
106 and 206 and air flowing outside of those tubes.
[0024] The specific number of fluid flow passages 222, the size of the flow area of
the individual fluid flow passages 222, and the longitudinal spacing between adjacent fluid
flow passages 222 may be selected on a case-by-case basis taking into consideration the size
of the manifolds, refrigerant flow volume and pressure drop requirements, and structural
considerations. By way of example for purposes of illustration, for a manifold assembly with
tubular manifolds having an internal diameter in the range of 15 to 25 millimeters, the fluid
flow passages between manifolds would typically have an internal diameter in the range of 2
to 4 millimeters and be spaced longitudinally at intervals ranging from 20 to 50 millimeters.
[0025] The process disclosed herein provides a method for manufacturing a multiple
manifold assembly, such as the dual barrel manifold assembly 220, with internal fluid
communication between the first manifold 104 defining a first fluid chamber 116 and the
second manifold 204 defining a second fluid chamber 216 of the manifold assembly.
Referring now to FIGs. 4A-4D, the method includes forming the manifold assembly 220 with
the first manifold 104 and the second manifold 204 joined in parallel relationship along a
longitudinally extending interface by a web 224 between an outer wall of the first manifold
104 and an outer wall of the second manifold 204, such as illustrated in FIG. 4A. In the
embodiment depicted in FIG. 4A, the manifold assembly 220 has been formed by an
extrusion process wherein a metal blank, such as for example, but not limited to, an
aluminum alloy blank, into the integral single piece dual barrel tubular manifold assembly
220. The extruded manifold assembly 220 includes a first tubular barrel forming the first
manifold 104, a second tubular barrel forming the second manifold 204, and a web 224
joining the tubular barrels along the longitudinal extent of the manifold assembly.
[0026] The method further includes forming at least a first access port 226 in a wall
of one of the first manifold 104 and the second manifold 204 diametrically opposite the
interface, for example in the first manifold 104 as illustrated in FIG. 4B, and then forming a
first fluid communication port 230, aligned with the first access port 226, that extends
through a wall of the first manifold 104 and a wall of the second manifold 204 at the interface
and the web 224 therebetween, as illustrated in FIG. 4C. If an additional fluid
communication port 230 is required, an additional access port 226 is formed in the manifold
104 longitudinally spaced from the first access port 226 to provide access for forming an
additional fluid communication port 230 longitudinally spaced from the first communications
hole 230. If further fluid communication ports 230 are required, the process is repeated with
an additional access ports 226 being formed in the first manifold 104 at longitudinally spaced
intervals for each fluid communication port 230. It is to be understood however that the
multiple access ports 226 can be formed simultaneously. Likewise, the multiple
communication ports 230 can be formed at the same time.
[0027] Each access port 226 provides access to the interior chamber 116 of the first
manifold so that a hole forming tool 225, shown in phantom lines in FIG. 4C, can form the
fluid communication port 230 extending through the wall of the first manifold 104, the web
224 and the second manifold 204 into the interior chamber 216 of the second manifold 204.
Each fluid communication port 230 defines a fluid passage 222 extending between the first
and second fluid chambers, 116, 216. Each access port 226 and corresponding aligned fluid
communication port 230 may be formed in a continuous operation using a single hole
forming tool. Or each access port 226 and corresponding aligned fluid communication port
230 may be formed using a two-step operation wherein the access port 226 is formed with a
first hole forming tool and then a second hole forming tool is inserted through the access port
226 for forming the fluid communication port 230.
[0028] If the port to be formed has a circular cross-section, the port may be formed
through a drilling operation with the port formation tool being a drill. However, if the hole to
be formed has a non-circular cross-section, the hole may be formed through a punching
operation with the port formation tool being a punch tool. In an embodiment, the method
includes first forming the access port by a first drilling operation and thereafter forming the
fluid communication port by a second drilling operation. In an embodiment, the method
includes first forming the access port by a punching operation and thereafter forming the fluid
communication port by a drilling operation. In an embodiment, the method includes first
forming the access port by a first punching operation and thereafter forming the fluid
communication port by a second punching operation. It has to be understood that a deburring
operation may be required, in case the drilling tool does not have such design feature.
Furthermore, the punching tool may be used for the circular hole formation for the
manufacturing efficiency.
[0029] The method further includes sealingly plugging each of the access ports 226.
As illustrated in FIG. 4D, to sealingly plug an access port 226, a plug 232 is inserted into the
access port 226 and subsequently metallurgically bonded to the manifold during the brazing
of the heat exchanger assembly in a brazing furnace, for example a controlled atmosphere
furnace. The plug 232 has a shaft 234 having a cross-sectional shape conforming to the
cross-sectional shape of the bore of the access port 226 and sized to be in a force fit
relationship with the bore of the access port 226. Additionally, the length of the shaft 234 of
the plug 232 may approximate the thickness of the wall of the manifold such that that end of
the shaft 234 is substantially flush with the inside wall of the manifold, whereby a flow
disturbance is not created by the shaft 234 of the plug 232 extending too deeply into the
interior chamber of the manifold. The plug 232 may further include an end cap 236 mounted
to an end of the shaft 234, the end cap 236 having a cross-sectional dimension, e.g. diameter
for a circular end cap, that is greater then a corresponding cross-sectional dimension, e.g.
diameter for a circular bore access port, of the plug shaft 234. The end cap may be
configured to abut against the outer surface of the manifold when the plug 232 is fully
inserted into the access port 226 and will provide an additional control of the insertion depth
for the plug 232.
[0030] The method disclosed herein may also be applied to multiple barrel manifold
assemblies having more than two manifolds. For example, referring to FIG. 5A, the method
disclosed herein may be applied to an integral extruded triple barrel manifold assembly 320
to form fluid flow passages between the interior fluid chambers 116, 216, respectively, of the
first and second manifolds 104, 204 and to form fluid flow passages between the interior fluid
chambers 216, 316, respectively, of the second and third manifolds 204, 304.
[0031] Referring to FIGs. 5B and 5C, the method includes forming at least one access
port 326 in a wall of the first manifold 104 and forming at least one access port 328 in a wall
of the third manifold 304, for example as illustrated in FIG. 5B, and then forming a fluid
communication port 322, aligned with the access port 326, that extends through a wall of the
first manifold 104 and a wall of the second manifold 204 and the web 224 therebetween, as
illustrated in FIG. 5C, and also forming a fluid communication port 324, aligned with the
access port 328, that extends through a wall of the third manifold 304 and a wall of the
second manifold 204 and the web 334 therebetween, as also illustrated in FIG. 5C. If
additional fluid communication ports 322 are required, additional access ports 326 may be
formed in the first manifold 104 at longitudinally spaced intervals from the first access port
326 to provide access for forming additional fluid communication ports 322 between the fluid
chambers 116 and 216. If additional fluid communication ports 324 are required, additional
access ports 328 may be formed in the third manifold 304 at longitudinally spaced intervals
from the first access port 328 to provide access for forming additional fluid communication
ports 324 between the fluid chambers 216 and 316.
[0032] Each access port 326 provides access to the interior chamber 116 of the first
manifold 104 so that a hole forming tool 225, shown in phantom lines in FIG. 5C, may be
inserted to form a fluid communication port 322 extending through the wall of the first
manifold 104, the web 224 and the second manifold 204 into the interior chamber 216 of the
second manifold 204. Each fluid communication port 322 defines a fluid passage extending
between the first and second fluid chambers, 116, 216. Each access port 328 provides access
to the interior chamber 316 of the third manifold 304 so that a hole forming tool 225, shown
in phantom lines in FIG. 5C, may inserted to form a fluid communication port 324 extending
through the wall of the third manifold 304, the web 334 and the second manifold 204 into the
interior chamber 216 of the second manifold 204. Each fluid communication port 324
defines a fluid passage extending between the third and second fluid chambers, 316, 216.
The fluid communication ports 322 and 324 may be formed in longitudinally staggered
arrangement relative to each other, whereby the fluid flow passages between the second and
third manifolds 204, 304 are offset from, rather than aligned with, the fluid flow passages
between the first and second manifolds 104, 204. Additionally, if the communication ports
322 connecting the first and second manifolds 104, 204 and the respective communication
ports 324 connecting the second and third manifolds 204, 304 are aligned, the aligned
communication ports can be formed by the port formation tool penetrating the outside wall of
one of the manifolds 104 or 304.
[0033] Furthermore, the communication ports 322 and 324 connecting the manifolds
104, 204 and 304, 204 respectively may be formed in different longitudinal positions to
connect different interior chambers 216 within the manifold 204 to the interior chambers 116
and 316 within the manifolds 104 and 304 respectively. For example, as illustrated in FIG.
6, wherein the interior chamber of second manifold 204 is subdivided by an internal wall 205
into a lower chamber 216-1 and an upper chamber 216-2, the communication ports 324 may
be positioned longitudinally to provide fluid flow communication between the interior
chamber 316 of the third manifold 304 and the lower chamber 216-1 of the second manifold
204, while the communication ports 322 may be positioned longitudinally to provide fluid
flow communication between the upper chamber 216-2 of the second manifold 204 and the
interior chamber 116 of the first manifold 104. The heat exchange tubes 106, 206 and 306,
which open into the interior chambers 116, 216 (216-1, 216-2) and 316, respectively, extend
into the page in the FIG. 6 sectioned view of the triple barrel header. The number and size of
the communication ports 322 and 324 can be different and highly depend on the amount of
vapor and liquid in the two-phase refrigerant mixture to maintain the desired refrigerant flow
distribution and appropriate pressure differential.
[0034] As discussed hereinbefore with respect to forming the fluid communication
ports 230 in the dual barrel manifold assembly 220 as illustrated in FIGs. 4A-4D, each access
port 326, 328 and corresponding aligned fluid communication port 322, 324 may be formed
in a continuous operation using a single hole forming tool, or each access port 326, 328 and
corresponding aligned fluid communication port 322, 324, may be formed using a two-step
operation wherein the access port 326, 328 is formed with a first hole forming tool and then a
second hole forming tool is inserted through the access port 326, 328 for forming the fluid
communication port 322, 324. Further, as discussed hereinbefore with respect to forming the
fluid communication ports 230 in the dual barrel manifold assembly 220 as illustrated in
FIGs. 4A-4D, each access port 326, 328 and corresponding aligned fluid communication port
322, 324 may be formed by a drilling operation using a drill as the hole formation tool or by a
punching operation using a hole punch as the hole formation tool.
[0035] The method further includes sealingly plugging each of the access ports 326,
328 in the same manner as discussed hereinbefore with respect to the dual barrel manifold
assembly, as illustrated in FIG. 5D. As illustrated in FIG. 5D, to sealingly plug an access
port 326, 328, a plug 232 is inserted into the access port 326, 328 in a force fit and
subsequently metallurgically bonded to the surrounding manifold wall during the brazing of
the heat exchanger assembly in a brazing furnace, for example a controlled atmosphere
furnace.
[0036] In an embodiment of the method disclosed herein, the communication ports
230, 322, 324 may be formed with a diameter sized such that the ratio of the manifold
internal diameter to the communication port diameter has a value in the range from 3 to 13,
inclusive, and the longitudinal spacing between adjacent communication ports connecting
adjacent manifolds may be selected such that the ratio of communication port spacing to the
manifold internal diameter has a value in the range from 0.5 to 4, inclusive, and such that the
ratio of communication port spacing to communication port diameter has a value in the range
from 5 to 25, inclusive.
[0037] Forming fluid flow passages between adjacent manifolds of an integral
manifold assembly having multiple manifolds in accordance with the method disclosed
herein eliminates the need for the U-bends or interconnecting piping linking manifolds as
typically needed in conventional multiple manifold assemblies for establishing fluid
communication between manifolds. Therefore, the higher cost, the higher corrosion risk and
the higher leakage risk associated with U-bends or interconnecting piping linking manifolds,
as well as the labor of hand brazing typically associated therewith, may be avoided through
use of the method disclosed herein.
[0038] While the present invention has been particularly shown and described with
reference to the exemplary embodiments as illustrated in the drawing, it will be recognized
by those skilled in the art that various modifications may be made without departing from the
spirit and scope of the invention. Therefore, it is intended that the present disclosure not be
limited to the particular embodiment(s) disclosed as, but that the disclosure will include all
embodiments falling within the scope of the appended claims.

We Claim:
1. A method for manufacturing a manifold assembly with internal fluid communication
between a first manifold defining a first fluid chamber and a second manifold defining a
second fluid chamber of said manifold assembly, the first manifold and the second manifold
joined in parallel relationship along a longitudinally extending interface between a wall of the
first manifold and a wall of the second manifold, said method comprising:
forming a first access port in a wall of one of the first manifold and the second manifold
diametrically opposite the interface;
forming a first fluid communication port extending through a wall of the first manifold and a
wall of the second manifold at the interface, said first fluid communication port defining a
first fluid passage between the first and second fluid chambers; and
sealingly plugging the access port.
2. The method as set forth in claim 1 further comprising forming said manifold assembly
as an integral manifold assembly by an extrusion process.
3. The method as set forth in claim 1 wherein forming the access port and the fluid
communication port comprises forming the access port and fluid communication port by a
drilling operation.
4. The method as set forth in claim 1 wherein forming the access port and the fluid
communication port comprises first forming the access port by a first drilling operation and
thereafter forming the fluid communication port by a second drilling operation.
5. The method as set forth in claim 1 wherein forming the access port and the fluid
communication port comprises first forming the access port by a punching operation and
thereafter forming the fluid communication port by a drilling operation.
6. The method as set forth in claim 1 wherein forming the access port and the fluid
communication port comprises first forming the access port by a first punching operation and
thereafter forming the fluid communication port by a second punching operation.
7. The method as set forth in claim 1 wherein sealingly plugging the access port
comprises inserting a plug in the access port in a force fit relationship with the manifold in
which the access port is formed and brazing the inserted plug to the manifold in which the
access port is formed.
8. The method as set forth in claim 7 wherein the inserted plug comprises an end cap and
a shaft extending from the end cap into the access port and the end cap abutting an external
surface of the manifold in which the access port is formed.
9. The method as set forth in claim 8 further comprising brazing the end cap to the
external surface of the manifold in which the access port is formed.
10. The method as set forth in claim 1 further comprising:
forming at least one additional access port spaced longitudinally from the first access
port;
forming at least one additional fluid communication port extending through through a wall of
the first manifold and a wall of the second manifold at the interface, said at least one
additional fluid communication port defining an additional fluid passage between the first and
second fluid chambers spaced longitudinally from the first fluid passage; and
sealingly plugging the at least one additional access port.
11. The method as set forth in claim 1 wherein at least one of the first access port and the
first fluid communication port is non-circular.
12. A method for manufacturing a manifold assembly with internal fluid communication
between a first manifold defining a first fluid chamber and a second manifold defining a
second fluid chamber of said manifold assembly and between a third manifold defining a
third fluid chamber and the second fluid chamber, said method comprising:
forming said manifold assembly with the first manifold and the second manifold joined in
parallel relationship along a first longitudinally extending interface between a wall of the first
manifold and a wall of the second manifold and with the second manifold and the third
manifold joined in parallel relationship along a second longitudinally extending interface
between a wall of the second manifold and a wall of the third manifold;
forming a first access port in a wall of the first manifold diametrically opposite the first
interface between the first manifold and the second manifold;
forming a first fluid communication port extending through the wall of the first manifold and
the wall of the second manifold at the first interface, the first fluid communication port
defining a fluid flow passage between the first and second fluid chambers;
forming a second access port in a wall of the third manifold diametrically opposite the second
interface between the second manifold and the third manifold;
forming a second fluid communication port extending through the wall of the third manifold
and the wall of the second manifold at the second interface, the second fluid communication
port defining a fluid flow passage between the second and third fluid chambers; and
sealingly plugging each of the first access port formed in the first manifold and the second
access port formed in the third manifold.
13. The method as set forth in claim 12 wherein forming said manifold assembly includes
forming the manifold assembly by an extrusion process as an integral manifold assembly
14. The method as set forth in claim 12 wherein the second manifold is divided into a first
interior chamber and a second interior chamber, the first fluid communication port forms a
fluid flow passage connecting between an interior chamber of the first manifold and the first
interior chamber of the second manifold and the second communication port forms a fluid
flow passage connecting between an interior chamber of the third manifold and the second
interior chamber of the second manifold.
15. The method as set forth in claim 12 wherein at least one of the first access port and
the first fluid communication port is non-circular.
16. A manifold assembly manufactured in accordance with the method set forth in claim
1.
17. The manifold assembly as set forth in claim 16 wherein each of the first and second
manifolds has an internal diameter and the first fluid communication port has a diameter
sized such that a ratio of the manifold internal diameter to the communication port diameter
has a value in the range from 3 to 13 for each of the first and the second manifolds.
18. The manifold assembly as set forth in claim 16 wherein each of the first and second
manifolds has an internal diameter and a longitudinal spacing between adjacent
communication ports connecting the first and second manifolds is selected such that the ratio
of communication port spacing to the manifold internal diameter has a value in the range
from 0.5 to 4 for each of the first and second manifolds.
19. The manifold assembly as set forth in claim 18 wherein a ratio of the communication
port spacing to the communication port diameter has a value in the range from 5 to 25.
20. A manifold assembly manufactured in accordance with the method set forth in claim
12.