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Publication numberUS3613782 A
Publication typeGrant
Publication dateOct 19, 1971
Filing dateAug 27, 1969
Priority dateAug 27, 1969
Publication numberUS 3613782 A, US 3613782A, US-A-3613782, US3613782 A, US3613782A
InventorsJohn L Mason, Robert W Greenwood
Original AssigneeGarrett Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Counterflow heat exchanger
US 3613782 A
Abstract  available in
Images(4)
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Claims  available in
Description  (OCR text may contain errors)

United States Patent Inventors John L. Mason Palos Verdes Estates; Robert W. Greenwood, Redondo Beach, both of Calif. App]. No. 853,248 Filed Aug. 27, 1969 Patented Oct. 19, 1971 Assignee The Garrett Corporation Los Angeles, Calif.

COUNTERFLOW HEAT EXCHANGER 16 Claims, 9 Drawing Figs.

US. Cl 165/166, 165/ 146 Int. Cl F281 3/00 Field of Search 165/146, 147, 166 MP References Cited UNITED STATES PATENTS 3,165,152 1/1965 Jones 165/166 3,228,464 1/1966 Steirn et a1. 165/166 3,282,334 11/1966 Stahlberger 165/166 3,322,189 5/1967 Tobouzian..... 165/166 X 3,508,607 4/1970 Hermann 165/166 X Primary ExaminerFrederick L. Matteson Assistant Examiher-Theophil W. Streule Attorneys--Albert .1. Miller and John N. Hazelwood ABSTRACT: A counterflow heat exchanger of the Z-flow or U-flow type in which the flow passage heights of each fluid are varied so as to minimize pressure drop.

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A ORNEY COUNTERFLOW I-IEA'll EXCHANGER BACKGROUND OF THE INVENTION A counterflow heat exchanger has the most efficient flow arrangement in that it most efiiciently utilizes the available temperature differential between the two working fluids. This type of flow arrangement is, however, especially awkward to manifold, particularly in a gas-to-gas heat exchanger.

One end section treatment for a gas-togas counterflow heat exchanger that has been developed to facilitate manifolding is the so-called Z-flow configuration. In the Z-flow heat exchanger, two fluids flow in adjacent uniform height passages separated by plates and closed by bars located as required at the edges of the passages. The first fluid flows directly across the heat exchanger from one manifold to a manifold on the opposite side of the heat exchanger. The second fluid enters the heat exchanger at a right angle to the flow of the first fluid, is the directed counter to the flow of the first fluid and finally out the opposite side of the heat exchanger again at a right angle to the flow of the first fluid. These changes in direction of the flow of the second fluid give rise to the Z-flow designation.

Since however, the crossflow sections (at right angles) of the Z-flow heat exchanger are inherently long and narrow, the pressure drop of the second fluid in these sections is excessive. Attempts to reduce the pressure drop in these sections have resulted in decreasing the counterflow character of the heat exchanger (hence its efficiency) and/or excessive increases in the pressure drop for the first fluid.

Other counterflow heat exchanger configurations, such as the U-flow type in which one of the fluids flows in a substantially U-shaped pattern, are likewise faced with the same inherent problems as the Z-shaped configuration.

SUMMARY OF THE INVENTION The present invention is an improved counterflow heat exchanger which reduces the pressure drop through the crossflow sections of the heat exchanger without reducing the counterflow nature of the heat exchanger or introducing excessive pressure drops elsewhere in the heat exchanger. The height of the Z-flow or U-flow passages is varied to provide a greater height in the crossflow sections than in the counterflow section. The height of the corresponding straight-through flow passages is likewise varied to compensate for the height variations in the Z-flow or U-flow passages.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the assembled heat exchanger of the present invention.

FIG. 2 is a perspective view of a single Z-flow passage of the assembled heat exchanger of FIG. 1.

FIG. 3 is a perspective view of a single straight-through flow passage of the assembled heat exchanger of FIG. 1.

FIG. 4 is an enlarged partial section view of the assembled heat exchanger of FIG. I taken along line 4-4 of FIG. 1.

FIG. 5 is a schematic plan view of the assembled heat exchanger of FIG. 1 illustrating the fluid manifolding.

FIG. 6 is a perspective view of a modified Z-flow passage.

FIG. 7 is a perspective view of a modified straight-through flow passage complementary to the Z-flow passage of FIG. 6.

FIG. 8 is a perspective view,- partially cut away of an alternate assembled heat exchanger of the present invention.

FIG. 9 is an enlarged partial sectionview of the assembled heat exchanger of FIG. 8 taken along line 9-9 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An assembled counterflow heat exchanger of the present invention is illustrated in FIG. I. This heat exchanger I0 comprises a series of alternate Z-flow passages 12 and straightthrough flow passages 14. The plurality of passages 12 and I4 are assembled between a heat exchanger top plate 16 and bottom plate I8. The entire assembly I0 may be brazed together by conventional brazing techniques.

A single Z-flow passage is shown in FIG. 2. This passage includes a triangular crossflow inlet section 22 having fins 24 running in the direction of fluid flow, a parallelogram counterflow section 26 having offset corrugated fins 28 and a triangular crossflow outlet section 30 having fins 32 in the direction of fluid flow. As indicated, the height of the crossflow sections 22 and 30 is greater than the counterflow section 26. An inlet header bar 34 closes the inlet end of the passage except for the crossflow inlet section 22 while an outlet header bar 36 closes the outlet end of the passage except for the crossflow outlet section 30. Side header bars 38 and 40 extend along both sides of the passage. A passage separator plate 42 is shown over the passage. to serve as a means to separate flow in adjacent passages.

FIG. 3 illustrates a single straight-through flow passage which includes a triangular crossflow inlet section 44 having fins 46 extending in the direction of fluid flow, a central parallelogram counterflow section 4% with offset corrugated fins 50, and a triangular crossflow outlet section 52 having fins 54 in the direction of fluid flow. The triangular inlet section 44,

centralparallelogrant section 48, and triangular outlet section 52 of the straight-through flow passage are adapted to correspond to the crossflow outlet section 30, parallelogram counterflow section 26 and crossflow inlet section 22 respectively of the Z-flow passages. Accordingly, the two triangular sections 44 and 52 are not as high as the central section 48 so as to accommodate the greater height of the crossflow sections 22 and 30 of the Z-flow passage when passages 12 and I4 are assembled into the heat exchanger 10. A passage separator plate 56 would be required between the top of the straightthrough flow passage 14 and the bottom of the adjacent Z- flow passage 12. End header bars 58 and 60 extending across the entire end are also required for the straight-through flow passage.

The heat exchanger 10 is formed of a stack of alternating passages 12 and I4 separated by plates 42 and 56. The varying heights of the respective passage sections are shown in FIG. 4. While not required, the hot fluid to be cooled will normally flow through the Z-flow passage 12 while the coolant will normally flow through the straight-through passage 14.

Manifolding for the heat exchanger 10 is conventional for a Z-type heat exchanger as shown schematically in FIG. 5. The Z-flow inlet manifold 62 which receives a heated fluid to be cooled communicates with the inlet crossflow section 22 of the stacked Z-flow passages 12. The heated fluid is prevented from entering the stacked straight-through passages 14 by the end header bars 60. The heated fluid proceeds through the crossflow inlet section 22 which distributes the fluid at various points to the counterflow section 26 which in turn passes the then cooled fluid to the crossflow outlet section 30. A Z-flow outlet manifold 64 collects the fluid from the Z-flow outlet sections 30 of the stacked Z-flow outlet passages 12. The coolant flows from the straight-through flow inlet manifold 66 through the straight-through flow passages 14, then out the straight-through flow outlet manifold 68.

Since the crossflow inlet and outlet sections 22 and 30 are relatively long and narrow, the fins therein, 24 and 32 are relatively nonrestrictive and the height of these two sections has been increased relative to the counterflow section 26 which includes more extensive fins 28 designed for greater heat transfer. The triangular sections 44 and 52 of the straightthrough passages 14 likewise have less restrictive fins 46 and 54 than the fins 50 in the central parallelogram section 48.

A modified Z-flow type heat exchanger can be formed of alternate passages of the Z-flow passage of FIG. 6 and the straight-through flow passage of FIG. 7. In this variation the counterflow sections 26' and 48' respectively are substantially rectangular rather than configured as a parallelogram. This embodiment provides a somewhat greater counterflow heat exchanger area than the basic Z-flow configuration of FIGS. 2 and 3.

In the Z-flow passage of FIG. 6, the height of the crossflow sections 22' and 30' having fins 24' and 32' respectively is greater than the counterflow section 26' having fins 28'.

Header bars 26', 36', 38', and 40' are provided as in the basic Z-flow configuration.

Likewise, the straight-through flow passage includes a counterflow section 48 having fins 50' whose height is greater than the crossflow section 44' and 52' having fins 46 and 54 respectively. Also headers 58' and 60' are provided.

An alternate end section treatment for a counterflow heat exchanger is the so-called U-flow configuration illustrated in FIGS. 8 and 9. The heat exchanger is comprised of an alternating stacked series of U-flow passages 72 and straight-through flow passages 74.

The straight-through flow passage 74 comprises a triangular crossflow inlet section 76 having fins 78 extending in the direction of fluid flow, a central rectangular counterflow section 80 with offset corrugated fins 82 and a triangular crossflow outlet section 84 having fins 86. End header bars 85 and 87 extend across the front and back respectively of each passage 74.

The U-flow passage 72 includes a triangular crossflow inlet section 88 having fins 90 extending in the direction of fluid flow, a central rectangular counterflow section 92 having offset corrugated fins 94 and a triangular crossflow outlet section 96 having fins 98 in the direction of the fluid flow. lnlet side header bar 100, end header bars 104, and outlet side header bar 102 together with passage separator plates 108 and 110 confine the fluid flow to the individual passages. A top plate 106 and bottom plate (not shown) confine the stacked passages of the heat exchanger.

As clearly indicated in FIG. 9, the height of the crossflow inlet and outlet sections 90 and 98 of the U-flow passage 72 is greater than the height of the counterflow section 92 of this passage. correspondingly, the crossflow sections 76 and 84 of the straight-through passage 74 have a lesser height than the central counterflow section 80. Manifolding of the U-flow configuration would be similar to that for the Z-flow configuration except that both the inlet and outlet manifold for the U- flow passages will be at the same end of the heat exchanger rather than at opposite ends.

The counterflow heat exchangers described above reduces the pressure drop of the fluid in previously high pressure drop sections of the heat exchanger without significantly decreasing the counterflow nature of the heat exchanger or excessively increasing the pressure drop in other of the heat exchanger sections.

While specific embodiments of the invention have been illustrated and described, it is to be understood that these embodiments are provided by way of example only and that the invention is not to be construed as being limited thereto, but only by the proper scope of the following claims.

We claim:

1. A heat exchanger comprising:

a plurality of first formed plates having a raised central portion;

a plurality of second formed plates having a depressed central portion corresponding to the raised central portion of said first formed plates;

said first formed plates and said second formed plates alternately disposed in a spaced, substantially parallel, relation to alternately form first fluid flow passages and second fluid flow passages in a heat transfer relationship;

said first passages having an upper first formed plate and a lower second fonned plate to form an inlet section, an outlet section, and central section, said central section formed by the raised central portion of said upper first formed plate and the depressed central portion of said lower second formed plate to have a flow height greater than the inlet and outlet sections;

said second passages having an upper second formed plate and a lower first formed plate to form an inlet section in a crossflow heat transfer relationship with the outlet section of said first passages, an outlet section in a crossflow heat transfer relationship with the inlet section of said first passages, and a central section in a counterflow heat transfer relationship with the central section of said first passages, said central section of said second passages formed by the depressed central portion of said upper second formed plate and the raised central potion of said lower first formed plate to have a flow height less than the inlet and outlet sections of said second passages.

2. The heat exchanger of claim 1 wherein the combined fluid flow height of the first passage inlet section plus the second passage outlet section equals the combined fluid flow height of the first passage central section plus the second passage central section equals the combined fluid flow height of the first passage outlet section plus the second passage inlet section.

3. The heat exchanger of claim 1 wherein said inlet and outlet sections of said first and second passages are substantially triangular and said central sections of said first and second passages are substantially parallelogrammic.

4. The heat exchanger of claim 3 wherein said central sections of said first and second passages are substantially rectangular.

5. The heat exchanger of claim 3 wherein the fluid flow in said first passages is substantially straight through and the fluid flow in said second passage 5 is substantially U-shaped 6. The heat exchanger of claim 14 wherein said central sections of said first and second passages are substantially rectangular.

7. The heat exchanger of claim 14 wherein the fluid flow in said first passages is substantially straight through and the fluid flow in said second passages is substantially U-shaped.

8. The heat exchanger of claim 3 wherein the fluid flow in said first passages is substantially straight through and the fluid flow in said second passages is substantially Z-shaped.

9. The heat exchanger of claim 8 wherein the inlet, outlet, and central sections of said first and second passages include heat transfer surfaces disposed therein, said heat transfer surfaces in said central sections substantially more restrictive to fluid flow than the heat transfer surfaces of said inlet and outlet sections.

10. A heat exchanger comprising:

a plurality of substantially rectangular first formed plates having a raised parallelogrammic central portion;

a plurality of substantially rectangular second formed plates having a depressed parallelogrammic central portion corresponding to the raised central portion of said first formed plates,

said first formed plates and said second formed plates al ternately disposed in a spaced, substantially parallel, relation to alternately form first fluid flow passages and second fluid flow passages in a heat transfer relationship;

said first passages having an upper first formed plate and a lower second formed plate to form a triangular inlet section, a triangular outlet section, and a parallelogrammic central section, said central section formed by the raised parallelogrammic central portion of said upper first formed plate and the depressed parallelogrammic central portion of said lower formed plate to have a flow height greater than the inlet and outlet sections, said first passages including edge closure elements disposed between said upper first formed plate and said lower second formed plate at the two short sides thereof;

said second passages having an upper second formed plate and a lower first formed plate to form a triangular inlet section in a crossflow heat transfer relationship with the triangular outlet section of said first passages, a triangular outlet section in a crossflow heat transfer relationship with the triangular inlet section of said first passages, and a parallelogrammic central section in a counterflow heat transfer relationship with the parallelogrammic central section said first passages, said second passage central section formed by the depressed parallelogrammic central portion of said upper second formed plate and the raised parallelogrammic central portion of said lower first formed plate to have a flow height less than the inlet and outlet section of said second passages, said second passages including long side edge closure elements disposed between the two long side edges of said upper second formed plate and said lower first formed plate and short side edge closure elements disposed between a portion of each of the two short side edges of said upper second formed plate and said lower first formed plate.

II. The heat exchanger of claim and in addition a first passage inlet manifold disposed along the inlet section long side of said first passages to provide fluid to said first passage inlet sections, a first passage outlet manifold disposed along the outlet section long side of said first passages to receive fluid from said first passage outlet sections, a second passage inlet manifold disposed along the portion of the inlet section short side of said second passages not closed by the short side edge closure elements to provide fluid to said second passage inlet sections, and a second passage outlet manifold disposed along the portion of the outlet section short side of said second passages not closed by the short side edge closure elements to receive fluid from said second passage outlet sections.

12. A heat exchanger comprising:

a plurality of first fluid passages for the flow of a first fluid;

a plurality of second fluid passages for the flow of a second fluid at a temperature different from said first fluid, said second fluid passages alternating with said first passages in a heat transfer relationship in the heat exchanger;

said first fluid passages having an inlet section at one end, an outlet section at the other end and an central section disposed between said inlet and outlet sections, said central section having a flow height greater than the inlet and outlet sections;

said second fluid passages having an inlet section in a crossflow heat transfer relationship with the outlet section of said first passages, an outlet section in a crossflow heat transfer relationship with the inlet section of said first passages, and a central section in a counterflow heat transfer relationship with the central section of said first passages, said second passage central section having a flow height less than the inlet and outlet sections of said second passages.

13. The heat exchanger of claim 12 wherein the combined fluid flow height of the first passage inlet section plus the second passage outlet section equals the combined fluid flow height of the first passage central section plus the second passage central section equals the combined fluid flow height of the first passage outlet section plus the second passage inlet section.

M. The heat exchanger of claim 12 wherein said inlet and outlet sections of said first and second passages are substantially triangular and said central sections of said first and second passages are substantially parallelogrammic.

15. The heat exchanger of claim 14 wherein the fluid flow in said first passages is substantially straight through and the fluid flow in said second passages is substantially Z-shaped.

H6. The heat exchanger of claim 15 wherein the inlet, outlet, and central sections of said first and second passages include heat transfer surfaces disposed therein, said heat transfer surfaces in said central sections substantially more restrictive to fluid flow than the heat transfer surfaces of said inlet and outlet sections.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,611,782 DatedOctober 19, 1971 Inventor(s) John L. Mason and Robert W. Greenwood It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Claim 5, line 3, change "passage 5" to --passages-- after "shaped" add Signed and sealed this 13th day of June 1972.

(SEAL) Attest:

EDWARD M.FLETCHER, JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
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US3228464 *Aug 9, 1963Jan 11, 1966Avco CorpCorrugated plate counter flow heat exchanger
US3282334 *Apr 29, 1963Nov 1, 1966Trane CoHeat exchanger
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3759323 *Nov 18, 1971Sep 18, 1973Caterpillar Tractor CoC-flow stacked plate heat exchanger
US3831374 *Jun 28, 1973Aug 27, 1974Power Technology CorpGas turbine engine and counterflow heat exchanger with outer air passageway
US4046529 *May 21, 1976Sep 6, 1977NasaRegenerable device for scrubbing breathable air of CO2 and moisture without special heat exchanger equipment
US4049051 *Jan 6, 1976Sep 20, 1977The Garrett CorporationHeat exchanger with variable thermal response core
US4804041 *May 13, 1986Feb 14, 1989Showa Aluminum CorporationHeat-exchanger of plate fin type
US5915469 *Jul 28, 1997Jun 29, 1999Tat Aero Equipment Industries Ltd.Condenser heat exchanger
US6032730 *Sep 9, 1997Mar 7, 2000Mitsubishi Denki Kabushiki KaishaHeat exchanger and method of manufacturing a heat exchanging member of a heat exchanger
US6125926 *Jul 24, 1998Oct 3, 2000Denso CorporationHeat exchanger having plural fluid passages
US6516874 *Dec 5, 2001Feb 11, 2003Delaware Capital Formation, Inc.All welded plate heat exchanger
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US7628199Mar 18, 2004Dec 8, 2009Behr Industrietechnik Gmbh & Co.Heat exchanger, in particular air/air cooler
US20040182555 *Sep 26, 2003Sep 23, 2004Rekuperator Svenska AbHeat exchanger device and a method for manufacturing the same
US20060231240 *Mar 18, 2004Oct 19, 2006Behr Industrietechnik Gmbh & Co.Heat exchanger, in particular air/air cooler
EP0097726A1 *Jun 24, 1982Jan 11, 1984Rockwell International CorporationA heat exchanger
EP1347260A1 *Dec 20, 2001Sep 24, 2003Honda Giken Kogyo Kabushiki KaishaHeat exchanger
EP1611406A1 *Mar 18, 2004Jan 4, 2006Behr Industrietechnik GmbH & Co.Heat exchanger, in particular air/air cooler
Classifications
U.S. Classification165/166, 165/DIG.391, 165/146
International ClassificationF28D9/00, F28F3/02
Cooperative ClassificationY10S165/391, F28F3/025, F28D9/0068
European ClassificationF28D9/00K2, F28F3/02D