US2877000A

US2877000A - Heat exchanger

Info

Publication number: US2877000A
Application number: US534791A
Authority: US
Inventors: Frank W Person
Original assignee: International Harverster Corp
Current assignee: Navistar Inc
Priority date: 1955-09-16
Filing date: 1955-09-16
Publication date: 1959-03-10
Anticipated expiration: 1976-03-10

Description

MarchlO, 1959 w, so v 2,877,000

HEAT EXCHANGER 6 Sheets-Sheet 1 i lllllllll Filed Sept. 16, 1955 INVENTOR N v! fi m P ..4 0 K M mnr F. W. PERSON HEAT EXCHANGER March 10, 1959 6 Sheets-Sheet 2 Filed Sept. 16, 1955 M/VE/VTUR FRANK W PERSON ATTORNEY March 10, 1959 F. w. PERSON HEAT EXCHANGER 6 Sheets-Sheet 3 Filed Sept. 16, 1955 //v VE/VTOR FRANK w. PERSON PM 03' ATTORNEY March 10, 1959 F, w, PERSON 2,877,000

HEAT EXCHANGER Filed Sept. 16, 1955 6 Sheets-Sheet 4 g, FRANK w. pmsa/v ATTORNEY March 10, 1959 F. w. PERSON 7,

I HEAT EXCHANGER Filed Sept. 16, v1955 6 Sheets-Sheet 5 m/ VEA/TOR J1! FRANK w. PERSON A r TQR/VEY March 10, 1959 F. w. PERSON 2,877,000

' HEAT EXCHANGER Filed Sept. 16, 1955 6 Sheets-Sheet 6 ""m. M Q F/G. Z

\JZQ T131 W J@ 1%: /J35 m #135 a 436 lA/VE/VTOR I I V A, W FRANK W. PERSON J ATTORNEY United States Patent IlEAT EXCHANGER Frank W. Person, Downers Grove,.-Ill., assignor to International Harvester Company, a corporationof New Jersey Application September 16, 1955, Serial No. 534,791

7 Claims. (Cl. 257-245) This invention pertains to an improvement in heat exchangers.

Conventional heat exchangers usually comprise a pair of spaced headers or chambers suitably connected by a plurality of individual tubes. The tubes in turn extend through a plurality of perforations or holes provided in relatively thin laterally spaced fins. The manufacture of the individual fins, the tubes, and their subsequent assembly into a suitable heat exchanger core is a relatively costly operation and though numerous machines and assembly techniques have been devised, heat exchanger cores are still relatively costly to manufacture. In the development of the welding art, a welding process has been devised which permits the relatively cheap manufacture of metal envelopes or members having as a necessarypart of their construction a plurality of tubular channels. This process is performed under various trade names but generally it can be called a recrystallization process. In the performance of the-process a fiat sheet, generally of aluminum or copper, has applied thereto a parting agent or organic compound. This parting agent may be applied to the sheet in printed form, the pattern of the said printing being the desired layout of the particular passages which are intended in the final product. A second sheet is then placed on top of the first-named sheet and both sheets are then subjected to a cold welding process. Such a cold welding process involves the use of pressure against the sheets and if necessary a low degree of heat may be employed during the application of said pressure. As the pressure is applied, a recrystallization of the contiguous sheets occurs thereby welding the said sheets together in all of the places except at the spots where'the parting agent has been applied to the original sheet. Thus a suitable envelope results, certain contiguous portions of the envelope, however, not being welded together in view of the action of the parting agent or organic compound which has been used. The envelope is then subjected to either hydraulic or pneumatic pressure. In other words, thespaces which are not welded together are connected to a source of hydraulic pressure and they are literally blown up causing the envelopes to have a pluralitp of elongated bead-like projections which form the passages desired'in the final product.

It has been found that this process is very inexpensive in manufacturing evaporator coils for refrigeration equipment. The so-called fins and tubular passages are thus integrally formed to provide an effective evaporator coil. It is a prime object of this invention, therefore,'to provide an improved heat exchangerhaving a plurality of heat transfer members with the passages and fins integrally formed and so disposed as to provide a more eificient construction which will also permit the application of the above mentioned process or similar processes in its manufacture.

A still further object is to provide an improved heat exchanger consisting of a plurality of panels disposed in heat exchange relation to provide a circuitous passage for the flow of fluid therebet-ween.

A still further object is to provide an improvedheat exchanger wherein the heat transfer members comprise a plurality of spaced envelopes which can'easily be assembled with the unit or disassembled for maintenance purposes.

A still further object is to provide an improved heat exchanger for oil coolers or radiators, the heat exchanger or transfer unit comprising a plurality of individual panelsadapted to be disposed in a position to secure maximum heat transfer efficiency.

These and other objects will become more readily apparent from a reading of the specification when. examined in connection with the accompanying sheets of drawings.

Figure 1 is a perspective'view, with a portion broken away, of a heat exchanger of a type generally utilized in connection with the cooling of liquids such as. oil;

Figure 2 is a cross sectional view through the heat exchanger shown in Figure 1, the view being taken along the line 2-2;

Figure 3 is an enlarged cross sectional view taken substantially along the line 3-3 of Figure 2;

Figure 4 is a cross sectional view taken substantially along the line 4-4 of Figure 2;

Figure 5 is a view similar to Figures 3 and 4 showing a modified disposal of certain heat exchange .members shown in Figures 1 through 4;

Figure 6 is a perspective view, with portions broken away to show the interior of the unit, the said unit comprising a heat exchanger of a type generally utilized in connection with the cooling of liquids;

Figure 7 is an enlarged sectional view taken substantially along the line 7-7.0f Figure 6;

Figure 8 is a side elevational view ofa'heat transfer member or envelope of a type usedin connection with the heat exchanger shown in Figure 6; 5

Figure 9 is a detailed view taken along the line 9- of Figure 8;

Figure 10 isa cross sectional view taken substantially along the line 10-10 of Figure 8;

Figure 11 is a cross sectional view, in enlargedform, taken substantially along the line 11-11- of Figure 8;

Figure 12 is an elevational view, similar to Figure 8, of another form of an envelope or heat exchangemember;

Figure 13 is a cross sectional View enlarged and taken substantially along the line 13-13 of Figure 12;

Figure 14 is a perspective view of another modifiedtype of heat exchanger, the said view having portions broken away to show certain interior portions of the unit;

Figure 15 is a cross sectional view taken along the line 15-15 of Figure 14;

Figure 16 is a cross sectionalyiew, showing the disposition of a plurality of heat transfer members the said yiew being taken along the line -16-16 of Figure 15;

Figure 17 is a view similar to Figure 16, the said view bging taken substantially along the line 17-17 ofFigure 1 Figure 18 is a perspective view of another modified type of heatexchange unit, the said view having portions broken away to show an interiorportion of the invention;

Figure 19 'is a cross sectional view taken along the line 19-19 of Figure 18;

Figure 20 is a cross sectional view, showing the-disposition of a plurality of heat transfer members, the said view being taken substantially alongtheline 20-20 of Figure 19;

Figure 21 is a detailed view taken substantially'along the line 21-21 of Figure 19;

Figure '22 is a perspective view of a heat exchanger of a radiator type;

Figure 23 is an enlarged plan view 'ofthe radiator 3 shown in Figure 22, the said view having certain portions broken away;

Figure 24 is a cross sectional view taken substantially along the line 24-24 of Figure 23; and

Figure 25 is a sectional view, showing the disposition ofaplurality of heat transfer members, the view being taken substantially along the line 2525 of Figure 24. 1 Referring now particularly to Figures 1 through 4, a heat exchanger, suitable for the cooling of fluids, is generally designated by the reference character 10. The heat exchanger comprises a housing or casing 11 having a front baffle or wall 12 and a rear bafile or wall 13 providing an inlet chamber 14 and an outlet chamber 15. The

chambers

14 and 15 also may be respectively considered as inlet headers and outlet headers. An inlet conduit or connection 16, provided on the casing 11, is in communication with the inlet chamber 14. In similar fashion an outlet conduit or connection 17 is in communication with the outlet chamber 15.

A plurality of heat transfer members or envelopes are designated at 18 and 19. Each of the

envelopes

18 and 19 is formed of a pair of sheet metal members 20 which are positioned in contiguous relation. The sheet metal members 20 may be of aluminum or copper, or similar non-corrosive material. Each of the sheet metal members 20 is provided with a plurality of horizontal arcuate projections 21, the said projections also being described as of elongated bead-like construction. Each sheet metal member further comprises a plurality of vertically disposed arcuate or bead-like projections 22 as best shown in Figure 2. The bead-like projections 21 are disposed in relatively complemental relation to provide a plurality of horizontally extending passages 23 and the vertical bead-like projections 22 are also positioned in complemental relation to provide a plurality of vertically extending passages 24. The arrangement of the

passages

23 and 24 is different in each of the

members

18 and 19, this difference also being well shown in Figures 3 and 4. Each of the

envelopes

18 and 19 is also provided with vertical end passages 25 communicating with the horizontal passages 23 and vertical passages 24 and also providing for communication between the

chambers

14 and 15. t

The

transfer members

18 and 19 may be easily and suitably made by the process described above. When manufactured by such a process the

members

18 and 19 are provided with a plurality of contiguous flat or bonded portions 26 which are disposed between the horizontal and

vertical passages

23 and 24, as indicated.

The

heat transfer members

18 and 19 are positioned in vertical laterally spaced relation as best shown in

Figtires

2 and 3. Each vertical end passage 25 communicates with either the

chamber

14 or 15. The front baffies 12 and rear bafiies 13 are suitably slotted to accommodate the

members

18 and 19 and to retain the same in the said position. A plurality of intermediate upper bafiles 27, as best shown in Figure 2, are provided within the casing 11. Each of the upper baffles is provided with suitably slotted portions 28 to accommodate the

transfer members

18 and 19 and to suitably position the same within the casing. Likewise, the lower portion of the casing is provided with an intermediate lower baflle 29 also having suitably slotted portions 30 adapted to engage and maintain the

transfer members

18 and 19 in suitably positioned relation. Each of the

transfer members

18 and 19 is provided withhorizontally extending oppositely disposed marginal edge portions 31, these edge portions being suitably in the slotted

portions

28 and 30. The casing 11 is also provided with an inlet connection 32 and an outlet connection 33, as best shown inFigures l and 2. Fluid may be directed through the inlet connection 32, the same being-circulated in the manner disposed indicated by the arrows in a circuitous manner and 3' The reference character 34, applied to the arrows, shows in efiect a circuitous passage for the flow of the fluid which is directed to the inlet connection 32. As shown in Figure 4, this circuitous passage provided between the envelopes or transfer members permits the flow of fluid in such a circuitous manner that it sweeps across the bead-like projections and causes a high maximum of heat transfer. For instance, the connection 16 may be connected to the crank case of an engine so that hot oil flows through the

passages

23 and 24 and out through the outlet 17. As it flows through these passages, cooling fluid such as water, etc. may be directed into the casing 11, the said fluid flowing in a circuitous andserpentine manner throughout the circuitous passages for eifectively and efliciently cooling the oil which is coursing through the

passages

23 and 24.

The contiguous fiat or bonded portions 26 also serve in the manner of fins to permit heat transfer as the cooling liquid sweeps through the circuitous arrangement of the bead-like projections. Thus a maximum heat transfer efliciency is effected. It can readily be seen that the lateral spacing of the

transfer members

18 and 19 may be varied depending on the particular construction desired. Similarly, the bead-like projections can be staggered in dilferent arrangements to secure maximum heat transfer efficiency. For instance, Figure 5 shows a variation in the design of the sheet metal members 20. Since the elements are essentially the same as in Figures 1 through 4, the same reference characters are applied. In this particular case the vertical bead-like projections 22 are of more shallow depth than these above described. It is apparent in this modification that the outer surfaces of the vertical projections 22 are disposed inwardly of the outer surfaces of the bead-like projections 21. Thus by placing the

transfer members

18 and 19 as shown in Figure 5, a nesting of the staggered horizontal bead-like projections is possible to provide a greater number of the metal members in each heat exchanger and to decrease the size of the circuitous passages designated by the reference character 34 which is directed against the arrow showing the fluid flow. As indicated, the outer wall of the casing 11 may also be escalloped or formed to accommodate the change in shape of the

sheet metal members

20 and 21.

Referring now to Figures 6 through 13 a somewhat modified heat exchanger, designated by the reference character 40, is disclosed. The heat exchanger 40 comprises a casing 41 having front baffles or walls 42 and rear baflles or walls 43. The

baffles

42 and 43 provide an inlet chamber or header 44 and an outlet chamber or header 45. An inlet conduit or connection 46 is in communication with the inlet chamber 44 and an outlet connection 47 is in communication with the outlet chamber 45.

As indicated in Figure 6, a plurality of envelopes or

heat transfer members

48 and 49 are positioned in upright laterally spaced relation within the casing 41. Each

transfer member

48 and 49 comprises a pair of sheet metal members 50, each of said members 50 being provided with a plurality of horizontal arcuate or bead-like projections 51 and a plurality of vertical arcuate or bead-like projections 52. The

transfer members

48 and 49 are similar to the ones above described and may be made with the same process above disclosed. The bead-like projections 51 of each member 50 are disposed in complemental relation to provide a plurality of horizontal passages 53. Similarly, the vertical projections are disposed in complemental relation to purovide a plurality of vertical passages 54. Opposite ends of each transfer member 48 are also provided with vertical end passages 55 in communication with the horizontal and

vertical passages

53 and 54, respectively. Only one of the vertical end passages 55 of each transfer member is shown in Figure 6 though it is apparent that each transfer member has opposite,ver

tical end passages 55 in communication with either of the chambers 44 and 45.

Each of the sheet metal members 50 is also provided with a plurality of relatively flat contiguous portions 56 disposed between the projections. As best shown in'Figure 6, the casing also includes a plurality of intermediate upper baflles 57 of comb-shaped construction having fingers or teeth 58. Similarly, an intermediate lower baffle 59 is provided, the same also having a plurality of spaced teeth 60. Each of the sheet metal membershas the contiguous flat portions 56 suitably bonded by welding as indicated in the above mentioned process or'by other suitable bonding means. Furthermore, marginal edge portions 61 disposed on opposite sides of the

members

48 and 49 are also suitably bonded-together. By referring to Figure 6 it will be noted that the baflle 42 is slotted, as indicated at 62, to accommodate the ends of the

transfer members

48 and 49. The wall or bafile 43 is similarly slotted.

As best shown in Figures 8 through 13, each of the

transfer members

48 and 49 is provided with a plurality of vertical grooves 63 which are recessed in the surfaces of the vertical projections 52. When the envelopes .48 and 49 are positioned in the casing, as shown in Figures 6 and 7,'the teeth 58 and 60 respectively, of the

members

57 and 59, engage the said grooves 63, thus suitably maintaining the

members

48 and 49 in suitable lateral spacing. Furthermore, the teeth serve to act as bafiies so as to direct the flow of liquid which courses into the casing in a circuitous manner between the projections and in a serpentine direction as indicated by the arrows. As indicated by the arrows, the passage thus provided by the baflles is relatively circuitous or serpentine as designated by the reference character 64 which is directed to the arrows showing the course of liquid.

Referring now to. Figures 14 through 17, another modified embodiment of the invention is disclosed. In these figures a heat exchanger 70 comprises a casing 71 having an inlet header or chamber 72 and an outlet header or chamber 73. As best shown in Figure 15 a battle 74 and a Wall 75 suitably separate said chambers. An inlet connection 76 is connected to the casing for communication with the chamber 72 and an outlet connection 77 communicates with the chamber 73.

As best shown in Figures 16 and 17, a plurality of heat transfer members or envelopes 78 are positioned within the casing 71. Each transfer member 78 consists of a pair of relatively thin sheet metal members 79, each of said members having a plurality of longitudinally extending bead-like projections, the said projections being positioned in complementary relation to provide a pair of generally U-shaped passages 81. The members 78 also comprise a plurality of marginal connected edge portions 82 and between the passages 81 a plurality of flat contiguous portions are provided on each of the members 78. As indicated by the recrystallization welding process above, the marginal contiguous edge portions may be suitably welded together to provide a fairly rigid structure with the passages provided therein. The heat trans fer members 78 are positioned so that an opening 84, communicating with the passages 81, is positioned within the chamber 72. Likewise, an opening 85 also in communication with the passages 81 is positioned in the outlet chamber 73.

Within the casing 71 there is provided also an inlet chamber 86 and an outlet chamber 87 separated partially by means of a partition wall 88. As best shown in Figures 16 and 17, the bead-like projections of the transfer members 78 are positioned in spaced relation to provide for the passage of fluid or liquid therebetween. An inlet connection 89 communicates with the chamber 86 and an outlet connection 90 provides for the exhaust of liquid from the chamber 87. The circuitous passages provided by the adjacent transfer members are generally indicated by the reference character 91Which is directed towardthe arrows-showing theparticular path of the liquid between'said transfer members. Thus here, like in the constructions above disclosed, the sheet metal members which provide for the transfer of heat are. made simply in panel form by the process described. Thus liquid flowing through the passages 81 can efiiciently be subjected to heat transfer by the flow of fluid through the various circuitous passages provided by the heat transfer members. Again it is, of course, obvious that variations .in the arrangement of the bead-likeprojections may be made so as in effect to staggerthem or to place them in cruciform relation as shown in the embodiments above disclosed.

Reference is now had to Figures 18 .through 21, wherein a heat exchanger includes a casing 101 provided with laterally spaced headers or

chambers

102 and 103. Walls 104 separate the

chambers

102 and 103, the .first of which is an inlet chamber and the second being an outlet chamber. An inlet connection 105 is in communication with the chamber 102 and an outlet connection 106 is in communication with the chamber 103.

As best shown in Figure 20, a plurality of heat transfer members or envelopes 107 are..positioned horizontally and in vertically spaced relation. Each transfer member 107 is made of a relatively thin sheet metal material having a plurality of bead-like projections 109 positioned in serpentine relation to provide a passage 1-10. The 'sheet metal transfer members 107 include oppositely disposed connected marginal edge portions 111 and relatively flat contiguous portions 112 disposed between the passages 110. One end of the passage opens as indicated at 113 into the inlet chamber 102 and the other end of the passage 110 opens as indicated at 114into the outlet chamber 103.

Within the casing 101an inlet chamber is designated at 115 and anoutlet chamber at 116. The chambers 115 and 116 are separated by a partition Wall-117. The partition wall 117 is spaced from one wall of the casing to permit the flow of liquid from the inlet chamber 115 to the outlet chamber 116. Thus it appears clear that fluid flowing into the chamber 115 flows in a circuitous path, as indicated by the arrow, over the projections and over the flat contiguous portions to effectively cool liquid flowing within the passages 110. The circuitous flow is, ofcourse, occasioned by the positioning of the'bead-like projections and these, of course, can be positioned in a number of various arrangements to provide different types of directed flow.

Figures 22 through 25 show a further modified embodiment of the invention. Herein a heat exchanger is designated by the reference character'120, the said exchanger being of the radiator type. The exchanger 120 comprises a casing 121 having upper and lower headers or

chambers

122 and 123. An inlet connection 124 directs liquid to the inlet header 122 and an outlet connection 125 discharges liquid from the header 123. A radiator supply connection is indicated at 126.

The header 122 is provided with alower wall 127 and .the header 123 is provided with an upper wall 128. A plurality of heat transfer members or envelopesv 129 are positioned in upright relation and relatively laterally spaced. The lower and

upper walls

127 and 128 are suitably slotted to permit the ends of the transfer members 129 to be disposed in the

headers

122 and 123. Each envelope or transfer member is comprised of a pair of relatively thin metal sheets, each of said sheets having bead-like projections which are disposed in complementary relation to provide a plurality-of vertically extending

passages

130 and 131. Here again the transfer members 129 may be made with a cold welding or recrystallization process as above described. Each transfer member comprises a plurality of flat contiguous portions 132 which are suitably bonded together. Likewise, opposite marginal edge portions 133 are suitably bonded together so that each transfer member is relatively. rigid,

having the

passages

130 and 131 disposed therein. As indicated in Figure 24, each of the relatively thin members of the transfer members 129 is also provided with a transversely extending bead 134, the said beads being disposed in complemental relation to provide open end passages on opposite sides of the transfer members, the said passages 135 providing communication between the

passages

130 and 131. An upper transfer passage of each transfer member is disposed within the header 122 and the lower transfer passage 135 of each transfer member is disposed in the lower header 123.

As indicated in Figure 25, the

passages

130 and 131 are positioned in relatively staggered relation so as to provide a plurality of circuitous passages through which air may flow when the radiator is utilized as a heat exchanger. By staggering the bead-like projections in the manner disclosed, the

passages

130 and 131 are staggered and air flow through said passages is of circuitous direction to effectively create a maximum efliciency heat exchange efiect on the

passages

130 and 131 and the liquid which is contained within the passages to be cooled. It is, of course, obvious again that various different staggered arrangements can be made, the most effective being, of course, the circuitous arrangement whereby the air sweeps all surfaces of the heat transfer member to effectively secure heat exchange eificiency.

Thus it is believed clear that various types of heat exchangers have been disclosed, each of said heat exchangers having novel type heat transfer members which may be manufactured by the simple process described. Maintenance of a heat exchanger of this type is relatively simple since all that need be done, if a transfer member is defective, is to remove the same and replace it with a new transfer member. The transfer members may thus be efiiciently and cheaply manufactured and various staggered patterns of the bead-like projections may be utilized to secure the relatively circuitous passages which are disclosed. In assembly the units, of course, are solder dipped in the conventional manner to secure sealing relation of the passages and the chambers as required.

Thus it is believed that the objects of the invention have been fully achieved and that an improved heat exchanger and modifications thereof have been fully disclosed. Further modifications may, of course, be made which do not depart from the spirit of the invention as disclosed nor thescope thereof as defined in the appended claims.

' What is claimed is:

1. A heat exchanger comprising a housing having spaced first chambers and a second chamber disposed adjacent said first chambers, a plurality of transfer elements disposed in said second chamber, each element comprising a relatively thin member having contiguous flat portions connected together .and elongated raised portions positioned in complementary relation to provide a plurality of passages extending horizontally and vertically in cruciform relation, said passages communicating with said first chambers, the horizontal passages of one element being positioned relative to the horizontal passages of an adjacent element in staggered relation with the raised portions of one element being disposed opposite to the flat portions of an adjacent element to provide a plurality of circuitous passages within the second chamber, a plurality of partitions within said second chamber, each of said elements having a plurality of vertically extending slots disposed on opposite sides of said elements in alignment with the vertical passages, each of said partitions being of comb-shape and having a plurality of teeth engaging said slots to divide said second chamber into a plurality of sub-chambers whereby fluid flowing through said circuitous passages will move through said sub-chambers in meandering fashion.

*2, A heat exchanger comprising a housing having spacedfirst chambers and a second chamber disposed adjacent said first chambers, a plurality of transfer elements disposed in said second chamber, each element comprising a relatively thin metal sheet member having contiguous flat portions connected together and elongated raised portions positioned in complementary relation to provide a plurality of passages extending horizontally and vertically in cruciform relation, said passages communicating with said first chambers, the horizontal passages of one element being positioned relative to the horizontal passages of an adjacent element in staggered relation with the raised portion of one element being disposed in opposite relation with respect to the flat portions of an adjacent element, to provide a plurality of second circuitous passages within said second chamber, a plurality of partitions within said second chamber, eachof said'elements having a plurality of vertically extending slots disposed on opposite sides of said elements, each of said partitions being of comb-shape andhaving a plurality of teeth engaging said slots to divide said second chamber into a plurality of subchambers whereby fluid flowing through said circuitous passages will move through said sub-chambers in meandering fashion.

3. A heat exchanger comprising a housing having spaced first chambers and a second chamber disposed adjacent said first chambers, a plurality of transfer elements disposed in said second chamber, each element comprising a relatively thin metal sheet member having contiguous flat portions connected together and elongated raised portions positioned in complementary relation to provide a plurality of passages extending horizontally and vertically in cruciform relation, said passages communicating with said first chambers, certain passages of one element being positioned relative to certain passages of an adjacent element in staggered relation, to provide a plurality of second circuitous passages within said second chamber, a plurality of partitions Within said second chamber, each of said elements having a plurality of vertically extending slots disposed on opposite sides of said elements, each of said partitions being of comb-shape and having a plurality of teeth engaging said slots to divide said second chamber into a plurality of sub-chambers whereby fluid flowing through said circuitous passages will move through said sub-chambers in meandering fashion.

4. A heat exchanger comprising a housing having spaced first chambers and a second chamber disposed adjacent said first chambers, a plurality of transfer elements disposed in said second chamber, each element comprising a relatively thin member having contiguous flat portions connected together and elongated raised portions positioned in complementary relation to provide a plurality of passages communicating with said first chambers, certain passages of one element being positioned relative to certain passages of an adjacent element in staggered relation with the raised portions of one element being disposed adjacent to and opposite the flat portions of an adjacent element to provide a plurality of second circuitous passages within the chamber, a plurality of partitions within said second chamber, each of said elements having a plurality of vertically extending slots disposed on opposite sides of said elements, each of said partitions being of comb-shape and having a plurality of teeth engaging said slots to divide said second chamber into a plurality of sub-chambers whereby fluid flowing through said circuitous passages will move through said sub-chambers in meandering fashion.

5. A heat exchanger comprising a housing having spaced first chambers and a second chamber disposed adjacent said first chambers, a plurality of transfer elements disposed in said second chamber, each element comprising a relatively thin metal sheet member having contiguous flat portions connected together and elongated raised portions positioned to provide a plurality of passages communicating with said first chambers, the fiat and raised portions of one element being offset with respect 'to the flat and raised portions of another element,

to provide a plurality of circuitous passages within said second chamber, a plurality of partitions within said second chamber, each of said elements having a plurality of vertically extending slots disposed on opposite sides of said elements, each of said partitions being of combshape and having a plurality of teeth engaging said slots to divide said second chamber into a plurality of subchambers whereby fluid flowing through said circuitous passages will move through said sub-chambers in meandering fashion.

6. A heat exchanger comprising a housing having spaced first chambers and a second chamber disposed adjacent said first chambers, a plurality of transfer elements disposed in said second chamber, each element comprising a relatively thin metal sheet member having contiguous flat portions connected together and elongated raised portions positioned to provide a plurality of passages communicating with said first chambers, the flat and raised portions of one element being ofiset with respect to the flat and raised portions of another element, to provide a plurality of circuitous passages within said second chamher, a plurality of partitions within said second chamber, each of said partitions being of comb-shape and having a plurality of teeth disposed between said elements to divide said second chamber into a plurality of sub-chambers whereby fluid flowing through said circuitous passages will move through said sub-chambers in meandering fashion.

7. A heat exchanger comprising a housing having spaced first chambers and a second chamber disposed adjacent said first chambers, a plurality of transfer elements disposed in said second chamber, each element comprising a relatively thin member having contiguous flat portions connected together and elongated raised portions to provide a plurality of passages communicating with said first chambers, the flat and raised portions of one element being ofi'set with respect to the flat and raised portions of another element, to provide a plurality of circuitous passages within said second chamber, a plurality of partitions within said second chamber dividing said second chamber into a plurality of sub-chambers whereby fluid flowing through said circuitous passages will move through said sub-chambers in meandering fashion.

References Cited in the file of this patent UNITED STATES PATENTS