US1935332A

US1935332A - Heat transfer device

Info

Publication number: US1935332A
Application number: US632971A
Authority: US
Inventors: Bert L Quarnstrom
Original assignee: Bundy Tubing Co
Current assignee: Bundy Tubing Co
Priority date: 1932-09-13
Filing date: 1932-09-13
Publication date: 1933-11-14
Anticipated expiration: 1950-11-14

Description

Nov. 14, 1933.

B. L. QUARNSTROM HEAT TRANSFER DEVICE 3 Sheets-Sheet 1 Filed Sept. 13, 1932 INVENTOR. 62W? 1,. QUfi/FMSTIFOM- 1 ATTORNEYS.

Nov. 14, 1933. B. 1.. QUARNSTROM HEAT TRANSFER DEVICE Filed Sept. 15, 1932 3 Sheets-Sheet 2 INVENTOR. 567? 7' L 001mm: TRON. f?

ATTORNEYS.

NOV. 14, 1933- QUARNSTRQM 1,935,332

HEAT TRANSFER DEVICE Filed Sept. 13, 1932 5 Sheets-Sheet 3 INVENTOR. 55191 L (Pu/2mm 7mm.

ATTO

Patented Nov. 14,1933- HEAT TRANSFER DEVICE Bert L. Quarnstrom, Detroit, Mich., assignor to Bundy Tubing Company, Detroit, Mich., a corporation of Michigan Application September 13, 1932 Serial No. 632,971

23 Claims.

This invention relates to a heat transfer device which may be employed as a condenser for mechanical refrigerators; as a core for the radiator of an automotive vehicle, airplane, lighter than aircraft, stationary internal combustion engine,

or the like; as a device for regulating the temperature of lubricating oil of an engine; as the radiator element of a hot water heater for auto mobiles and the like; or for-general heating and cooling purposes in buildings. This application is a continuation in part of my prior application Serial No. 626,760, filed July 30, 1932.

The permissible height and width of an automobile radiator are limited by considerations such as size of the vehicle, wind resistance, appearance, and stream-lining at the front end of the vehicle. Accordingly it has been proposed to obtain greater radiating area and cooling capacity by increasing the dimensions of the radiator at right angles to its plane, which dimension may be termed the depth of the radiator. It is well known however that the cooling efficiency at the rear of the radiator is far less than at the front of the radiator so that the increase in cooling effect that can be obtained in this way is limited. Various means such as baflles have additionally been employed, without, however, affecting in any way the fact as stated above that thegreatest cooling efiect is obtained at the front of the radiator while the water at the rear of the radiator is cooled only slightly. Hence it has heretofore been impracticable to reduce 'the frontal area of an automobile radiator to the desired extent or to obtain high cooling efiiciency for a radiator of a'given size.

In heat transfer devices embodying the present invention, the heat transfer eificiency throughout the device is equalized so that the entire body of a fluid circulating through the device is substantially equally affected, either by cooling or by heating the same as the case may be. For example, in contrast with automobile radiators of the tube typeand the cellular type, an automobile radiator embodying the present invention provides that the entire body of water flowing through the device follows the same or a substantially parallel heat transfer path and is equally cooled throughout. To this end a plurality of streams of water, instead of flowing downwardly each in substantially the same vertical direction from top to bottom as in the tube and cellular types, are each caused to -flow horizontally back and forth in the direction of the depth of the radiator and throughout substantially its entire depth. It will be understood that each reversal of flow takes place at a lower level so that each stream gradually moves downwardly in a generally vertical direction, following what may be describe specificallyas a horizontal path alternately reversed indirection. The result is that the streams of water pass through heat transfer paths that are the same as to cooling effect for all streams, and that the body of water in each stream moves back and forth between the front and back of the radiator and is broken up and thoroughly mixed by reversing its direction of flow, so that the cooling efficiency of the radiator is equalized from front to back of the radiator and all parts of the body of water are equally cooled.

Another factor of importance in the design of an efficient heat transfer device is to provide a large total heat transfer area of material of high heat conductivity in order to obtain an efficient transfer of heat between the two fluids. In a radiator or other heat transfer device embodying the present invention, a multiplicityof streams of small cross-sectional area are provided, the structure forming these tubes providing a large external radiating fin areaand the path being relatively long so that the cooling effect is increased. -Moreover, the horizontal partitions be tween adjacent reversely directed portions of each stream constitute internal fins of large area which conduct the heat out of the water and to the cooling air. These internal fins can be formed integrally with the external radiating fins as described hereinafter so that the heat does not have to be conducted across soldered, welded, or other joints.

Tests have shown that a heat transfer device of the new type described generally above, and more particularly hereinafter, when employed for example as an automobile radiator, is remarkably more efiicient than automobile radiators heretofore used, the K value being in cases tested as much as 50% and more above the K value of prior radiators. This means that the size of the radiator (or other heat transfer device) can be correspondingly reduced with a resultant saving in material and cost. Furthermore, in the case of vehicles the frontal area of the radiator can be reduced to permit stream-lining, a result hitherto made difiicult by the requirement for a large frontal radiator area as determined by previous standards of cooling efficiency.

Hence it is an object of the invention to provide a novel heat transfer device suitable for use as a radiator and for other purposes which is of such design that the above described operation is carried out and the results of equalized heat transfer efiiciency together with thorough mixing of the streams of fluid and equal cooling or heating of all parts thereof are attained.

A further object is to provide a novelheat transfer device wherein the heat transfer eflillO ciency as determined by the K value of the device is greatly increased, whereby the size of the device required for any particular purpose can be reduced.

A further object is to provide a novel heat transfer device wherein the tortuous paths described 'above are provided without the formation of pockets or obstructions to thefiow through the device.

A still further object is to provide a device of the class described wherein corrosion is prevented by a non-corrodible material.

Another object is to provide a novel heat transf er device which is improved from the standpoints of mechanical strength, liability to development of leaks, and ease, flexibility and economy of manufacture.

Generally speaking, the core of a heat transfer device embodying the invention can be constructed in any suitable way. Preferably, however, a multiplicity of core elements are provided, each comprising a strip of material having a. width equal tothe depth of the core and having a plurality of trough-like depressions extending transversely of the strip and formed by casting, stamping, drawing, etc. Preferably also these core elements are integral and are each formed of a single piece of metal having good heat conduc-- 'tivity, such as iron or steel, aluminum, copper,

brass, etc. When the core elements are assembled as hereinafter described to form the core, they may be secured together in fluid-tight relation in any suitable way such as soldering, welding or in some cases merely by pressing them together. The specific method may depend somewhat on the material used; for example, cast aluminum core elements are most conveniently soldered together, whereas copper and brass core elements are soldered or brazed. Excellent results have been obtained by stamping the depressions in copper coated steel strips and welding the elements together by the copper hydrogen welding process, this method providing core elements having the structural strength of the steel strips with the corrosion resisting qualities of copper, the elements being welded together and the copper being alloyed to the steel so that the joints are perfectly fluid-tight and almost as strong as the steel itself. Furthermore, a core comprising a stack or series of stacks of troughs can be cast as an integral unit of any desired or suitable metal.

' In such a device embodying the invention one fluid enters at the top of the transfer device and passes out at the bottom, flowing through the numerous chambers which .are afforded by the juxtapositioned trough-like depressions which are disposed horizontally and extend from a point near the front surface of the device to a point near the rear surface of the device.

The drawings show several embodiments of the invention as illustrations of the many uses of the invention enumerated above. It is to be expressly understood, however, that the invention is not limited either to these particular uses or to the specific structural embodiments illustrated and that the drawings are not to be construed as a definition of the limits of the invention, reference being had to the appended claims for this purpose.

In the drawings:

Fig. 1 is a side elevational view of a radiator structure embodying the invention with some parts cut away and some parts in section;

menace Fig. 2 is an end view with some parts cut away and some in section;

Fig. '3 is an enlarged sectional view taken on line 3-3 of Fig. 4;

Fig. 4 is an enlarged sectional view at right angles to that of Fig. 3 and taken on line 4-4 of Fig. 3;

Fig. 5 is a perspective view of a portion of a core element showing the trough formations;

Fig. 6 is a sectional view similar to that of Fig. 4 illustrating a modified structure in which the invention is embodied;

Fig. 7 is a sectional view illustrating a modified form of header structure;

Fig. 8 is a side elevational view with parts cut away and parts in section illustrating a core of a radiator for an automotive or other vehicle;

Fig. 9 is a front elevational view thereof, illustrating the modified form of core element;

Fig. 10 is an enlarged sectional view illustrating a modified form of trough for obtaining the gravity drain;

Fig. 11 is a View taken substantially on line 1l11 of Fig. 10;

Fig. 12 is a sectional view illustrating a form with modified trough dimensions;

Fig. 13 is a fragmentary plan view of one of the trough members illustrated in Fig. 12;

Fig. 14 is a sectional view taken substantially on line i l-14 of Fig. 12;

Fig. 15 is an enlarged sectional view illustrating troughs made from individual plates, as also shown in Fig. 9.

Fig. 16 is a sectional view taken through a radiator structure in the form of a casting.

Fig. 17 is a view partly in section and partly in side elevation looking on line 1717 of Fig. 16 showing two cast sections connected.

Fig. 18 is a sectional view taken on line 18-18 of Fig. 16.

First referring to Fig. 5, a core element is illustrated at 1, the same being relatively long and narrow, and positioned crosswise of the strip and substantially parallel to each other are troughs 2. These troughs are shown in cross section in Figs. 3 and 4 and each has end walls 3 and 4 (Fig. 4), side walls 5 and 6 (Fig. 3), and a bottom wall 7. These troughs may be provided in any suitable way; where the elements 1 are of sheet metal, a simple stamping operation is preferred, either in the form of a single die operation where the metal will withstand the drawing and thinning, or of two or more successive die operations where it is desirable to lessen the thinning and drawing of the metal. 1

as illustrated at 12, provides additional fin areas.

A suitable number of core elements thus formed are disposed in juxtaposition preferably in superimposed relation with the troughs of one element fitting into the troughs of the next adjacent element, as illustrated. The

walls

3 and 4 are preferably inclined, as are also the walls 5 and 6, so that the troughs are of tapering formation with the bottom of each trough of smaller overall of the lowermost core element.

dimensions than its open top. Accordingly, a plurality of the elements maybe superimposed and pressed tightly together so that the troughs on juxtapositioned elements tightly fit into each other. Once assembled, the core elements can be secured together and the engagement between the interfitting troughs can be made fluid-tight in any suitable way. In some instances it will sufiice merely to press the elements tightly together and hold them by clamps or tie rods. It is generally preferable, however, to solder, braze or weld the elements together, more particularly at their contacting trough portions. Good welded or soldered joints' will generally form sufficient mechanical connection between the elements, although clamps, tie rods or any suitable framework can be employed in addition.

Prior to the assembling of the elements, apertures 13 are provided in the bottoms of the troughs in any suitable way as by a punch operation: While all of the core elements, save perhaps the lowermost and uppermost, in the complete assembly are substantialy identical, every other one is reversed end for end to locate the apertures 13 of adjacent troughs at opposite ends of a chamber formed by the trough formations. The walls of each two adjacent troughs provide a chamber between them, as illustrated at 14, and fluid passes through one aperture 13 leading into this chamber and then horizontally through the chamber 14 and out through the aperture 13 at the other end. The fluid then reverses its horizontal flow through the next lower chamber, and so on through the entire structure. The portions 12 cooperate as illustrated in Fig. 3 to provide passageways 15 for another fluid.

As clearly shown in Fig. 4, the bottom 7 of each.

trough may be inclined from its unapertured end toward its apertured end, this being accomplished during the stamping, casting or other forming operation by making one end wall 4 of each trough longer or deeper than the other end wall 3. This construction provides a gravity drain throughout the core and avoids the formation of pockets in which the circulating fluid might be trapped or deposits of dirt, sediment, etc., might accumulate. In this connection it should be noted that the flow area of the apertures 13, while preferably as great as the mean flow area of the passages or chambers 14, may, if desired, be made smaller so as to constrict the flow through a part or all of the device without interfering in any way with the uniformity of size of the core elements, the radiating area of the device, or

other characteristics thereof.

In the form shown, a header cap plate19 is utilized at the top of the device and is suitably shaped to provide a header chamber 20, and the topmost core element is of such dimensions as to provide sufficient metal to be fashioned over the edges of the header plate, as illustrated at 21. A suitable conduit connection, as shown at 23, is provided to conduct fluid to or from the device.

A header of any suitable type is provided at the lower end of the structure, and as shown it comprises a header plate 24 having suitable apertures formed therein for the reception of the troughs These apertures are illustrated at 25 and are advantageously defined by flanges 26 which embrace the outside of the troughs of the lowermost sheet metal element. A base plate 2'7 is fashioned to provide a shoulder 28, and the header plate 24 has its edge portions flanged as at 29 for fitting against the shoulder 28, and the header plate 24 may have its edge portions flanged as at 29 for fitting againstthe shoulder 28. A suitable conduit 30 may be connected into the header chamber 31 provided by the header plate 24 and base plate 27.

In the operation of such a heat exchange device it may be assumed that the particular device shown is for use as a condenser for a refrigerant which enters through the conduit 23 and passes into chamber 20. The fluid then passes in a plurality of streams through the troughs. Each stream passes substantially horizontally first to the right and then to the left, as Fig. 4 is viewed, finally passing through the structure from the uppermost header to the lower header space 31, and thence out the conduit 30. Air may be blown or drawn through the device by a suitable fan or blower, ,if such is desired, and such air contacts with the fins or

areas

10 and 11 and passes through the passageways 15 thus having intimate contact with the heat dissipating portions 12 and with the side walls 5 and 6 of the troughs. cordingly, a very extensive integral heat exchange area is afforded thus making the device a, particularly efficient one for heat transfer.

The device shown in Fig. 6 comprises essentially the same structure as that heretofore described -and the same reference characters are applied thereto, thus eliminating duplicate description. This device illustrates how the troughs may be materially increased in length, thus providing longer horizontal passageways for the flow of fluid therethrough. This increased length may be desired in some instances where an increase in heat transfer area is wanted.

A modified form of header structure is shown in Fig. 7. The plates with the trough formations are illustrated at 40 with their apertures disposed in accordance with the disposition of the apertures in the foregoing forms. The header comprises a cap plate 41 and another plate 42, the edges of one being fashioned over the other. In the form illustrated the edges 43 of the plate 41 are fashioned over the edges of plate 42, forming a header chamber 44 to which is connected a conduit 45. The plate 42 has apertures therein for receiving the trough-like formations of the top.

plate 40 so that the edges of the two uppermost plates may engage opposite sides of the plate 42 as shown. The topmost plate 40 may be disposed generally above the plate 42 with its troughs extending through the apertures in plate 42, and the next lower plate may be fitted to the troughs of the topmost plate.

In Figs. 8 and 9 there is shown the core of a radiator for an automobile, aircraft or any other walls of which all extend a uniform distance from the plates 53 as distinguished from the form shown in Fig. 4 wherein one end wall 4 extends farther fromthe plate 1 than the other end wall 3 in order to provide the desired inclination of the bottoms '7 for the' purpose of gravity drain. As shown in Figs. 10 and 11, the inclination of the bottoms of the troughs 54 is provided by depressing each bottom out of its normal plane as illustrated at 55, the depressed portions inclining toward the ends of the troughs in which the apertures 56 are formed and appearing as illustrated in Fig. 11. While Figs. 8 and 9 show a radiator having troughs of the form illustrated in Figs. 10 and 11, they may employ the trough arrangement illustrated in Figs. 3 and d.

In the form shown in Figs. 12, 13 and 14, the troughs 57 are somewhat longer and narrower than in the preceding forms, the depressed portions 58 of the trough bottoms extending the 811-- tire width of the trough bottoms and having arc'uate cross sections which merge smoothly into the lower edges of the side walls of the troughs. The apertures 59 also extend the entire width of the trough bottoms and are elongated in the direction of the length of the troughs until their flow area is substantially equal to the mean flow area of the troughs 57. If desired, however, the flow through all or part of the device may be restricted by decreasing the elongation of the apertures 59. As shown in Fig.13, no shoulders or constrictions are left around the apertures at the ends of the troughs, the fluid draining freely therethrough and from the arcuate lips formed by the ends of the depressed portions 58 of the trough bottoms. This form of trough can be substituted for either of those described above whenever desired.

Instead of providing a plurality of troughs in a single integral core element, each trough can be formed in an individual sheet or plate of metal as illustrated in Fig. 15. This Figure 15 shows an enlarged sectional view of such an arrangement wherein each vertical row of chambers formed by the troughs is provided by a stack of separate plates or sheets 60 each having one trough 61 formed therein. The several stacks may be placed in close proximity preferably with their'edges slightly spaced as shown. This structure permits of disposing the troughs in closer relation than is feasible where the troughs are formed in one sheet of metal so that formed in one sheet there must be some spacing between them in order to provide metal for the forming operation, particularly where sufficient metal must be provided for a gathering action. Moreover, this method of making and assembling the core structure provides great flexibility of manufacture, since the plates 60 can be made up in quantities and assembled as desired into cores of widely varying types and sizes. Where individual sheets or plates are used they may be trimmed as desired either before or after the formation of the trough. In disposing the troughs formed of individual plates in close proximity, the fin area is reduced and the amount of fin area required may determine the spacing between the troughs. It will be observed that a radiating fin 62 is provided around the troughs in the individual plates, and that an additional radiating area is aiforded by the edges of each plate.

In such a structure, particularly where there is a considerable flow of liquid through the chambers formed thereby, it is preferred that the flow of liquid therethrough be fairly uniform. In this connection the size or area of the apertures in the bottoms of the troughs are preferably such as substantially to correspond to the cross sectional area or flow area of the chambers formed by the troughs. For this reason the elongated aperture of Figs. 12 and 13 may be employed where the trough is relatively narrow in which case a circular aperture having a diameter equal to the width of the trough would not provide sufficient flow. Obviously, where the bottoms of the troughs are inclined the chambers formed thereby are not of uniform cross sectional area, and in such a case the area of the apertures may correspond substantially to the mean flow area of the chambers. However, as indicated above it may be desirable in some'cases to employ apertures which have a flow area less than the mean flow area of the chambers. In this way the flow through a heat transfer device of any given size and type can be restricted as desired, and also the how through one part of the device can be restricted as regards the flow through another part of the device. Attention is also called to the fact that the device is so constructed as to avoid the formation of pockets in which the fluid or solid matter carried thereby could be trapped. This is due to the inclined bottoms of the troughs and the apertures extending substantially the width of the trough bottoms, whereby continuous uninterrupted flow through the device is obtained. The speed of flow of a fluid through the device can be regulated by varying the pitch or inclination of the trough bottoms and the size of the apertures.

The various elements going into the structure, particularly the core elements with the troughs and the header plates, are generally to be joined This may be done by uniting the various elements where they contact with each other by 195 sealing them together with any suitable sealing material, preferably, metal which has been rendered molten. Solder may be employed for this purpose; by solder is meant an alloy of tin and lead; higher fusing point brazing or welding 11 metals may be employed, such as an alloy embodying copper and zinc, silver solder or the like. The preferred manner of uniting the elements where they contact with each other is that of employing the so-called copper hydrogen welding process. This comprises utilizing copper suitably" located so that when the structure is subjected to coppermelting temperature in a reducing environment, for example, such as hydrogen, the copper becomes molten, runs in between the contacting surfaces, and upon cooling effectively unites the elements. Where copper-coated ferrous metals are employed, for example, the copper coatings become welded together and also alloy with the ferrous metal, forming a welded perfectly fluid-tight joint having very great structural strength almost equal to that of the ferrous metal itself. In this connection it is pointed out that it is unnecessary to pre-coat the core element with copper since the copper will flow in between surfaces fitted extremely tightly together and, in fact, it is practically impossible to have two surfaces so tightly fitted that the copper will not flow therebetween. Where sheets or plates of ferrous metal such as low carbon steel and coated with copper are utilized, the trough formations can be made by a stamping operation and the entire core welded together to form a very strong unit. Moreover, the copper coatings become a1- loyed to the steel stock and uniformly distributed A thereover, so that the entire unit both inside and out is corrosion-resistant. This copper welding process, from a broad standpoint, is known to those versed in the art.

A radiator thus constructed has been found to of this invention, that is to say, the coefficient of thermal conductivity in heat units transferred per unit of time, per unit of area, per unit of temperature differential, exceeds the K value of other known radiator structures, some as high as about 100%, and another as high as about 50%. The most efllcient radiator of the known types which were tested was exceeded in eiiiciency by the pres! removes considerable heat so that at the front side the efficiency may be relatively high, but since the air is'warmed by this action, the efficiency of the radiator at the rear side is relatively low. As a result the depth of these radiators is limited from a practical standpoint. In a radiator comprising a series of tubes running through fin plates, or having fins attached thereto, there is a marked diiferential between the efiiciency at the front and rear sides of the radiator. In the cellular type of radiator in which the streams of water passing therethrough are of a width sub stantially equal to the depth of the radiator, allowing for requisite metal thickness and fin area, the differential of the efficiency at the front and rear sides is still marked.

With a construction embodying the present invention and as described above, the water flows from the top of the radiator to the bottom of the radiator in a general vertical path by passing therethrough in a multiplicity of streams. Each stream, however, as it passes through the chambers, has a movement through each chamber which is generally horizontal extending substantially through the depth ofthe radiator. The movement of each stream may be termed that of a horizontal, alternately reversed path. A stream of water flows through one chamber, say from the front of the radiator to the rear and down to the next lower chamber, and then horizontally through that chamber from the rear to the front, and so on through the entire structure. Therefore, the water which is at one instant at the rear of the radiator is at the next instant at the front of the radiator so that all the water passing through the device is subjected to substantially the same cooling effects. In radiators of known types, wherein a series of tubes are usedwith some tubes behind the others, the water in the rear tubes is entirely disassociated from the water in the front tubes, and such water in the rear tubes is subjected only to slight cooling-effects. The same thing is true, generally, in a cellular type of radiator where a wide stream passes through the radiator, because the portion of the stream near the rear of the radiator is not subjected to eflicient cooling action. As explained above, this is'not true of radiators embodying the present invention wherein the entire body of water is subjected to the same cooling effect.

Moreover, in a radiator embodying the present invention a certain amount of agitation or turbulence is given to the streams of water as the same pass from one chamber to another through the relatively sharp bends at the connecting ends of the chambers. In addition, it will be observed that the heat which enters the

end walls

3 and 4, the side walls 5 and 6- and bottoms 7 may be conducted directly along these walls to the

fin areas

10, 11 and 12, and where the plates are copper coated, the heat-may be conducted directly along the coated surfaces as the copper affords an excellent heat conductor. By refer-. ring to Fig. 4 and considering the plate member with the trough second from the top, the heat may be conducted directly to the fin portions on this plate; however, some of the heat may bridge the joint between this plate and the next lower plate and be dissipated in the fin portions of the next lower plate. Furthermore, the bottoms of the troughs constitute internal fins of relatively large area which are in direct contact with the water in the streams both above and below them, and therefore constitute effective means for absorbing heat from within the streams and conducting it out to the radiating

fins

10, 11 and 12.

The increased efliciency obtained with struc tures embodying the present invention makes it possible to obtain a given heat transfer effect with a smaller unit, which is generally desirable inorder to obtain the advantages of decreased amount of material, weight and size. Moreover, in the case of automotive vehicles this decrease in size is important in that it permits redesign of the front end of such vehicles along stream lines. Heretofore stream-lining the front end of a vehicle such as an automobile has been very difficult because of the large frontal radiator area required to provide suflicient cooling capacity. With the increased efficiency and decreased size obtained by the present invention, this handicap to stream-lining is greatly reduced. Moreover, these advantages are obtained simultaneously with the provision of a radiator which is of inherent mechanical strength, not subject to development of leaky joints or corrosion either inside or out, and particularly well adapted for manufacture in large quantities.

In the specification and in some of the claims it is stated that the fluid passes through the device generallyin a vertical direction with a horizontal flow to the streams. It will be understood that the terms vertical and horizontal are employed in a relative sense only to describe the operation of the devices illustrated, and are not to be construed as limiting the use of structures embodying the invention in any way. Moreover, it will be understoodthat the invention is not limited to radiators, strictly speaking, and that the term radiator when used in the appended claims is intended to include the structure defined whether used as a radiator or condenser or for other similar purposes.

A radiator incorporating the invention may be made of one or more castings. This is shown in Fig. 16; the casting may comprise a header 70, a header '71, and an intermediate section having chambers 12 separated by shelf-like members 73 constructed to provide connecting apertures between chambers as illustrated at '14. The shelf lid like. members are preferably inclined to provide for gravity flow. Integral fins v may be on the casting. A number of such castings may be connected together to form a single radiator structure and as illustrated in Fig. 17, the header members 70 may be connected by means of a flanged bushing 76 and a nut 77 screwed onto one end of it. In making the casting core holes may appear where necessary, and they may be closed or plugged in any suitable manner. By way of illustration, two of such coreholes are shown in Fig. 16, the same being plugged as at 18.

What is claimed is:

l. A core structure for a heat transfer device comprising, a plurality of superimposed metal plates, each plate having formed therein a number of trough-like depressions defined by side walls, end walls, and a bottom wall, said plates being disposed in superimposed relation with the troughs interfitting, the bottoms of the interfitting troughs together with the side and end walls of the troughs cooperating to define fluid chambers, the bottom of each trough having an aper ture therein near one end, and juxtapositioned troughs having their apertured ends respectively disposed near opposite ends of the said chambers, the bottom of each trough being inclined downwardly from its closed end to its apertured end to provide a gravity flow through the transfer device.

2. A heat transfer device comprising, a plurality of metal plates, each plate having formed therein a number of trough-like depressions defined by side walls, end walls, and a bottom wall, said plates being disposed in a vertical superimposed relation with troughs of adjacent plates interfitting, the bottoms of interfitting troughs being spaced from each other and defining, together with the side and end walls, fluid chambers, the bottom of each trough having an aperture therein near one end only, and juxtapositioned troughs having their apertured ends respectively disposed near opposite ends of the said chambers, header means over the top and bottom plates for conducting fiuid to and from the several troughs in these plates, whereby thefiuid passes through the transfer device in a general vertical direction and in a plurality of streams running through the apertures and chambers, said chambers providing a horizontal flow for the streams.

3. A heat transfer device comprising, a plurality of metal plates, each plate having formed therein a number of trough-like depressions defined by side walls, end walls, and a bottom wall, said plates being disposed in a vertical superimposed relation with troughs of adjacent plates interfitting the bottoms of interiitting troughs being spaced from each other and defining, together with the side and end walls, fluid chambers, the bottom of each trough having an aperture therein near one end, and juxtapositioned troughs having their apertured ends respectively disposed near opposite sends of the said chambers, header means over the top and bottom plates for conducting fluid to and from the several troughs in these plates, whereby the fiuid may pass through the transfer device in a general vertical direction and in a plurality of streams running through the apertures and chambers, said chambers providing a horizontal flow for the streams, the bottoms of the troughs being inclined downwardly from their closed ends to their open ends whereby to provide a gravity flow through the heat transfer device.

.4. A heat transfer device comprising a pluralat least one trough-like rasaasa ity of metal plates each having trough-like depressions therein oi tapering form, said troughs being relatively long and each having an aperture through its bottom atone end only, alternate plates being reversed end for end, and a plurality of said plates being disposed in superimposed relation with the troughs interfitting, the bottoms of interfitting troughs defining fluid chambers with an aperture at each end, whereby to provide a plurality of tortuous fluid passageways through the plates, plate members disposed over the end plates of the said superimposed plates and providing header chambers, and all of said plates being united one to another at contacting portions by sealing material.

5. A radiator core for transferring heat from one fluid to another and through which a current of air or the like is adapted to be passed in the direction of the depth of the radiator, comprising a plurality of metal plates each having depression therein which is relatively long and narrow, each trough having an aperture in its bottom near one end only, said plates being disposed in superimposed relation with the troughs interfitting, the walls and bottoms of the troughs defining chambers for thepassage of fluid therethrough with each chamber having an aperture near one end for connecting into one adjacent chamber and an aperture near its opposite end for connecting into another adjacent chamber, said chambers having their long dimensions extending substantially in the direction of the depth of the radiator whereby a fluid passing through the radiator is directed through interconnecting chambers in a stream which traverses substantially the depth of the radiator with a reverse direction of flow in alternate chambers, each plate having portions projecting from a trough-like depression and constituting fin areas for contact with the current of air.

6. A radiator core for transferring heat from one fluid to another and through which a current of air or the like is adapted to be passed in the direction of the depth of the radiator, comprising a plurality of metal plates each having at least one trough-like depression therein which is relatively long and narrow, each trough having an aperture in its bottom near one end, said plates being disposed in superimposed relation with the troughs interfitting, the walls and bottoms of the troughs defining chambers for the passage of fluid therethrough with each chamber having an aperture near each end for connecting into adjacent chambers, said chambers having their long dimensions extending substantially in the direction of the depth of the radiator whereby a fluid passing through the radiator is directed through interconnecting chambers in a stream which traverses substantially the depth of the radiator with a reverse direction of flow in alternate chambers, each plate having portions projecting from a trough like depression and constituting fin areas for contact with the current of air, each trough having side and end walls of substantially uniform depth and the bottom of each trough being inclined substantially from its closed end to its apertured end whereby to provide a gravity flow for the fluid.

'7. A radiator core for transferring heat from one fluid to another and through which a current of air or the like is adapted to be passed in the direction of the depth of the radiator, comprising a plurality of metal plates each having at least one trough-like depression therein which is relatively long and narrow, each trough having an aperture in its bottom near one end, said plates being disposed in superimposed relation with the troughs interfitting, the walls and bottoms of the troughs defining chambers for the passage of fluid therethrough with each chamber having an aperture near one end for connecting into an adjacent chamber and an aperture near its opposite end for connecting into another adjacent chamber, said chambers having their long dimensions extending substantially in the .direction of the depth of the radiator whereby a fluid passing through the radiator is directed through interconnecting chambers in a stream which traverses substantially the depth of the radiator with a reverse direction of flow in alternate chambers, each plate having portions projecting from a trough-like depression and constituting fin areas for contact with the current of 'air, each aperture in the bottom of a trough having an area for the flow of fluid therethrough which substantially corresponds to the mean flow area of the chambers.

8. A radiator core for transferring heat from one fluid to another and through which a current of air or the like is adapted to be passed in the direction of the depth of the radiator, comprising a plurality of metal plates each having at least one trough-like depression therein which is relatively long and narrow, each trough having any aperture in its bottom near one end, said plates being disposed in superimposed relation with the troughs interfitting, the walls and bottoms of the troughs defining chambers for the passage of fluid therethrough with each chamber having an aperture near each end for connecting into adjacent chambers, said chambers having their long dimensions extending substantially in the direction of the depth of the radiator whereby a fluid passing through the radiator is directed through interconnecting chambers in a stream which traverses substantially the depth of the radiator with a reverse direction of flow in alternate chambers, each plate having portions projecting from a trough-like depression and constituting fin areas for contact with the current of air, each trough having side and end walls of substantially uniform depth and the bottom of each trough being inclined substantially from its closed end to its apertured end whereby to provide a gravity flow for the fluid each aperture in the bottom of a trough having an area for the flow of fluid therethrough which substantially corresponds to the mean flow area of the chambers.

9. A radiator for transferring heat from one fluid to another and through which a current of air or the like is adapted to be passed in the direction of the depth of the radiator, comprising a plurality of metal plates each having a single trough-like depression therein which is relatively long and narrow, each trough having an aperture in its bottom near one end only, a plurality of said plates being disposed in superimposed relation to form a tier of plates with the troughs interfitting and alternate plates reversed end to end, the walls and bottoms of the interfitting troughs defining chambers for the passage of fluid therethrough with each chamber connecting at opposite ends with adjacent chambers and each chamber having its long'dimension extending substantially in the direction of the depth of the radiator, a plurality of tiers of said plates being disposed side by side, header means at the top and at the bottom of said tiers,- whereby fluid passing through the radiator from one header to another is divided into streams each flowing through a series of interconnected chambers of a tier of plates, and each stream traversing substantially the depth-ofthe radiator in flowing through the chambers with reverse direction of flow in alternate chambers, each plate having porfluid to another and through which a current of air or the like is adapted to be passed in the direction of the depth of the radiator, comprising a plurality of metal plates each having a single trough-like depression therein which is relatively long and narrow, each trough having an aperture in its bottom near one end only, a plurality of said plates being disposed in superimposed relation to form a tier of plates with the troughs interfitting and alternate plates reversed end for end, the walls and bottoms of the interfitting troughs defining chambers for the passage of fluid therethrough with each chamber connectingv at opposite ends with adjacent chambers and each chamber having its long dimension extending substantially in the direction of the depth of the radiator, a plurality of tiers of said plates being disposed side by side, header means at the top and at the bottom of said tiers, whereby fluid passing through the radiator from one header to another is divided into streams each flowing through a series of interconnected chambers of a tier of plates, and each stream traversing substantially the depth of the radiator in flowing through the chambers with reverse direction of flow in alternate chambers, each plate having portions constituting fin areas for contact with the current of air and projecting from the troughlike depression therein, said plates being united r and sealed together-to close said chambers by sealing material.

11. A radiator core for transferring heat from one fluid to another and through which a current of air or the like is adapted to be passed in the directionof the depth of the radiator, comprising a plurality of metal plates each having at least one trough-like depression therein which is relatively long and narrow, each trough having an aperture in its bottom near one end only, alternate plates being reversed and-said plates being disposed in superimposed relation with the troughs r interfitting and united by melted sealing metal, the walls and bottoms of the interfitting troughs defining chambers for the passage of fluid therethrough, each chamber having its long dimension extending substantially in the direction of the depth of the radiator whereby fluid passing through a series of interconnected chambers traverses substantially the depth of the radiator with reverse direction of flow in alternate chambers, each plate having portions projecting substantially from the open side of the trough therein constituting fin areas for contact with the current of air passing through the radiator.

12. A core structure for a heat transfer device comprising walls of heat conductive material forming a plurality of superposed chambers elongated in a horizontal direction, each pair of adjacent chambers having a common intermedipassing downwardly through said chambers flows horizontally through the individual chambers and oppositely in consecutive chambers, and substantially horizontal radiating fins extending from said walls.

14. A core structure for a heat transfer device comprising walls forming a plurality of vertical structures each elongated in one horizontal direction to substantially the depth of the device and each divided by spaced generally horizontal walls into a plurality of superposed horizontal chambers extending substantially the depth of the device, said walls forming the bottoms of said chambers and adjacent chambers having apertures at opposite ends of their bottoms whereby each of a plurality of streams passing downwardly through one of said structures flows horizontally back and forth through consecutive chambers, and fins extending from said walls in horizontal planes adjacent each chamber and forming passages through which a second fluid flows in contact with said fins and the side walls of the chambers.

15. A core structure for a heat transfer device comprising a plurality of assembled metal members rigidly secured together and shaped to form one or more rows of superposed chambers elongatedin a horizontal direction, each pair of adjacent chambers having a common intermediate wall and alternate intermediate walls having apertures at opposite ends of their bottoms, the bottom wall of each chamber being inclined toward its apertured end, said members providing outwardly extending fin portions adjacent each chamber and in substantially horizontal planes.

16. A core structure for a heat transfer device comprising a plurality of assembled members of copper-coated ferrous metal shaped to form a vertical structure elongated in a horizontal direction and divided by spaced generally horizontal partitions into a plurality of superposed, elongated horizontal chambers, adjacent partition walls being apertured at opposite ends, said members providing outwardly extending radiating fins adjacent ,each chamber, and the copper coatings being welded together at contacting portions of said members, whereby a welded, fluidtight and copper-coated core structure is provided. j

17. A core structure for a heat transfer device comprising a plurality of assembled members of copper-coated ferrous metal, said members forming a plurality of vertical rows of superposed elongated horizontal chambers, the bottom walls of adjacent chambers being oppositely inclined and having apertures at their lowermost ends,

said members also providing horizontal radiating fins adjacent and integral with each chamber, the contacting portions of said members being welded together whereby a welded, fluid-tight and copper-coated core structure is provided.

18. A core structure for a heat transfer device comprising walls of heat conductive material il,985,$839l forming a plurality of superposed chambers elongated in a horizontal direction and radiating fins extending outwardly therefrom in substantially horizontal planes, the bottom wall of each.chamber being depressed out of its normal plane into arcuate formation and the bottom walls of adjacent chambers being oppositely inclined and apertured at their lower ends.

19. A=core structure for a heat transfer device comprising walls of heat conductive material forming a plurality of superposed. chambers elongated in a horizontal direction and radiating fins extending outwardly therefrom in substantially.

horizontal planes, the bottom wall of each chamber being depressed out of its normal planeinto arcuate formation and the bottom walls of adjacent chambers being oppositely inclined and apertured at their lower ends, said apertures extending the entire width of the bottoms of said chambers.

20. A core structure for a heat transfer device comprising walls of heat conductive material forming a plurality of superposed, elongated, horizontal chambers and radiating fins extending outwardly therefrom in substantially horizontal planes, adjacent chambers having apertures at the opposite ends of their bottoms whereby a fluid passing downwardly through said chambers flows horizontally'back and forth through consecutive chambers, said chambers each extending substantially the entire depth of the device, said apertures having a flow area substantially equal to the mean flow area of said chambers.

21. A core structure for a-heat transfer device comprising walls of heat conductive material forming a plurality of superposed, elongated, horizontal chambers and radiating fins extending outwardly therefrom, the bottom walls of adjacent chambers having apertures at opposite ends and being inclined downwardly toward their apertured ends, certain of said apertures having a flow area less than the mean flow area of said chambers in order to constitute restric-. tion.

22; In a radiator core, the combination of a plurality of metal plates each having a troughlike depression formed therein, said troughs being of increased depth toward one end thereof whereby the bottom walls thereof are inclined and said bottom walls being apertured at their deep ends, said plates being assembled with said troughs interfitting and with interfitting troughs reversed end for end to form chambers with the bottoms ,of adjacent chambers oppositely inclined, said'plates forming radiating fins integral with the side and end walls of said chambers.

23. A core structure for a heat transfer device comprising walls of heat conductive material forming a plurality of superposed chambers elongated in a horizontal direction and each chamber extending from the front to the rear of the core structure, each pair of adjacent chambers having a common intermediate wall adjacent chambers having apertures at opposite ends of their bottoms so that a fluid passes through said