US2874940A

US2874940A - Heat exchanger

Info

Publication number: US2874940A
Application number: US226582A
Authority: US
Inventors: Ahlen Karl Gustav
Original assignee: Svenska Rotor Maskiner AB
Current assignee: Svenska Rotor Maskiner AB
Priority date: 1951-05-16
Filing date: 1951-05-16
Publication date: 1959-02-24
Anticipated expiration: 1976-02-24
Also published as: FR1060883A

Description

K. G. AHLEN HEAT EXCHANGER Feb. 24, 1959 4 Sheets-Sheet 1 Filed May 16, 1951 a k w lNgENTQR.

ATTORNEY eb. 24,- 1959 V K. G. AHLEN Filed May' 16, 1951 HEAT EXCHANGER 4 Sheets-Sheet 2 Fig.5.

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A TTORNEY Fig.9.

- HEAT EXCHANGER Filed May 16, 1951 Y 4 Sheets-Sheet s 106 1 11a 104 Ho m 1 4 358 106 1 110 Fig.11.

a INVENTOR.

ATTORNEY Feb. 24, 1959 I G. AHL-EN HEAT EXCHANGER Filed May 16, 1951 4 Sheets-Shegt 4 771 III a IN V EN TOR. a fls l, .f

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A TTORNEY United States Patent HEAT EXCHANGER Karl Gustav Ahln, Stockholm, Sweden, assignor .to Svenska Rotor Maskiner Aktiebolag, Necka, Sweden, a corporation of Sweden Application May 16, 1951, Serial No. 226,582

Claims. (Cl; 257-=-241) The present inventionrelates to heatxtransfer "and-in its broader aspects has reference toheat transfer between ,heat. exchange at high rates of transfer per unit area' of heat exchanging surface, to provide forsuch transfer with minimum expenditure of power for eflecting relative movement between the heat exchanging bodies and in certain of. its aspects to utilize movement of the solid heat exchanging body to create, in whole or ,in part, there- I quired flow of the fluid or fluids with which the solid body is inheat exchange relation.

In order to attain the above generally stated objects and other and more detailed objects hereinafter appear- .ing, the invention contemplates the provision of Qrotating solid body in the form of a rotor having a multiplicity of circular fins or ribs with intervening channels inthe -form of grooves concentric with the axis of rotation of the rotor, with which'there is associated a rotationally stationary structure having bafile members projecting into the grooves and cover means for. the grooves for controlling flow of fluid in the grooves, such structure further being combined with means providing transfer passages for conducting fluid to and from diflerent grooves inac- 'cordance with novel principles hereinafter more fully described, which result in a novel character of flow which is productive of the improved results sought by the invention.

The invention is particularly adapted for heat exchange between two gaseousfiuids'for purposes such as-the pre- .heating of air to be used for combustion, by waste heat extracted from combustion-gases exhausted from; apparatus such as power boilers and internal combustion engines and-gas turbines. The invention will therefore be described hereinafter, by wayof example but Without limitation, as applied to air preheating structure, but it will be understood that the principles of the invention are susceptible of use in many other applications andthat for certain of such applications, the principles of the inven* tion in its broader aspects may be carriedout with only certain features of the structure hereinafter .describedin connection with the air preheater apparatus chosen by way of example. I

For a better understanding of the more detailed nature of the invention, the manner in which it maybe carried into practical effect, and the advantages to be derived from its use, reference may best be had tothe ensuing portion of this specification, taken in conjunction with the accompanying drawings forminga part hereof, inwhich:

Fig.1 is a more or less diagrammatic longitudinal secof member 30.

"ice

tion, online 1--1 of Fig. 2, ofan air preheatingapparatus embodying theprinciples ofthe invention;

Fig. '2, and-with certain elements indicatedlinjphantom for the sake of clarity;

Fig. 4 is a fragmentary perspective view of part of the structure shown in the precedingzfigures and with certain elements omitted for the sake of clarity;

Fig. 5 is a view, similar to' Fig. 3, showing a different structural arrangement of certain of the parts. for producing. an. altered character of. fluid flow;

Fig. 6 is afragmentary crosssection taken on the line 6-6 of Fig. 5;

Fig. 7 is .afragmentary; perspective view, similar to Fig. 4, of the arrangement shown in Fig 5;

Fig. 8 is a view similar to Figs. 3 and. 5 showing an other arrangement of structure for producing fluid flow of different character than that shown in Figs. 3 and 5;

Fig. 9 is a fragmentary cross section taken on line 99 ofFig. 8;

Fig.. 10' is a. fragmentary longitudinal. section. taken on line 10--.-10 of Fig. 8; I

Figill'is a view, similar to Fig. 8, showing structure providing an altered character'of fluid flow as compared with that of Fig. 8;

Fig. 12 is a longitudinal.sectionsimilar to'. Fig. lshowing apparatus embodyingthe invention arid having adifplicity of external axially spacedv radialifins or ribs 22,

providing between them a multiplicity of external annular channels or grooves 24. The drum further carries'a multiplicity of similar internal ribs 26 providing a multiplicity of internal annular grooves 28.

Associated with the rotor there is provided a rotationally stationary s'tructure comprising a' hollow drumlike internal casing memberindicate'd generally at 30. Member '30 is mounted "coaxiallywiththe' rotor and has a cylindrical casing wall 32 radially spaced'from the inner ends of the internal ribs26. "It further is provided with an inlet 34 at one end and outlets 36 at the other end.

The stationary structure further comprises an outer drumlike casing'wall 38surrounding the rotor'and radially spaced from the external ribs 22. i The stationary structure further has

end walls

40 and 42,-the former extending inwardly past the end wall 16 offtherotor to shaft part 12 of the rotor where aseal 41may' be employed, and the latter extending inwardly to the inlet portion 34 An inlet duct 44; for fluid communicates by way of opening 46' at one end of the rotor withthe space 48 between rotor wall 18 and the outer casing 38. This space communicates 'at'the other end of the rotor by way-of an opening 4? with the outlets 50 'and 52.

The wall'54 extends inwardly to a seal diagrammatically indicated at '56 and with wall 42 providing an outlet duct ber30 through theinlet 34 and nows in'the direction of arrows 62 through member30. From this space'the'air flows -generallyfrom right to left as vie'wedinFig-l,

add-ih -amanner hereinafter described more in detail,

through the space 60 between the rotor drum l8 -and similar to passage 86.

differ in that they are oblique in opposite directions with M wer A,

i F I 3 the wall 32 of member 30, and from this space to the outlet duct 58.

Hot fluid, such as spent combustion gases, enters in the direction indicated by arrow 64 through inlet duct 44 and opening 46 to the space 48 between the rotor drum 18 and the outer casing Wall 33. The gas flows generally from left to right as viewed in Fig. 1 through this space in a manner hereinafter to be described and through opening 50 to the outlet duct 52.

The wall 32 of member 30 carries a plurality of battle members 66 extending axially of the rotor and peripherally spaced around the circumference of wall 32.

These members are of comb-like form having a multip- I licity of fingers 68 projecting into and substantially filling the cross sections of the grooves 28. Similar comb-like bafile members 70 extend inwardly from the outer casing wall 38 and are provided with fingers 72 substantially filling the cross sections of the external rotor grooves 24.

Externally of the ribs 22 and located peripherally in spaced relation between the battle members 70, a plurality of cover members 74 extend axially in closely spaced relation to the crests of the ribs 22. These cover members are supported by means of partition or guide plates 76 carried by the casing wall 38, as will be more clearly seen from Fig. 3. These partitions extend peripherally from one baffle 70 to the next and comprise oblique central portions 78 overlying the cover members 74 and transverse end portions 80. The end portions 80 of these partitions extend beyond the edges of the cover members to the adjacent baflles and divide the spaces between the edges of the cover plates and the baffles into two series of axially aligned ports between each two adjacent bafiles. One series of such ports is indicated at 82, 82a, 82b and 82c, and the other is indicated at 84, 84a, 84b and 840, in Figs. 3 and 4. These ports provide communication between the sectors of the grooves 24 between the adjacent battles and the space between the bafiles which lies radially outside the cover 'members or plates 74, the latter space being divided by the partitions into a series of oblique transfer passages as indicated at 86, 86a, 86b and 860 in Figs. 3 and 4,

these passages being defined bythe cover plate '74, the l radially outer parts of bafiles 70, the outer casing wall 38 and the partitions 76.

Radially inside the rotor drum 18, a similar structure is provided comprising cover plates 88 disposed adjacent to the crests of the inner ribs 26 and series of partitions or guide plates 90 for supporting the cover plates and forming series of ports 92'and 94, and together with the cover plates 88, the inner casing wall 32 and adjacent inner bafiles 66 providing oblique transfer passages 96 Transfer passages 86 and 96 respect to the rotor axis.

The operation of the apparatus described is as follows:

Considering first the gas entering through duct 44 and opening 46, this gas enters radially a group of grooves 24 through inlet ports 82 distributed around the periphery of the structure. It being assumed that the rotor is turning in the direction indicated by arrow 98 in Fig. 4, friction between the gas and the surface of the moving ribs causes the gas streams in the grooves to move pcripherally in the direction of rotation of the rotor under the cover plate 74 until they are forced radially out of 1 the grooves by the fingers 72 of the bafile members 70, which substantially block or dam the grooves.

If we now consider the action of the gas streams in the portionof the apparatus shown in Fig. 3, it will be apparent that the streams entering the grooves through streams flow until'ejected-through port 84a into transfer passage 86b which carries the air to the inlet port 8211 *bylthe relatively dirty combustion gases.

of a succeeding set of grooves. This action is repeated until the gas reaches the discharge end of the rotor and from Fig. 4 it will be evident that the gas column entering port 82, which is divided into individual streams in the grooves, travels in what may be said to be a generally helical path to flow along the rotor between two adjacent batlies. From the preceding description, it will be obvious that peripherally of the rotor there will be a series of such gas columns each confined between two adjacent bafiies and moving in generally helical paths along the rotor.

The action with respect to flow through the grooves between the inner flanges 26 is the same as being described and for the apparatus assumed, theair enters through duct 34 and is divided into a number of air columns each flowing between adjacent baffles in a generally helical path along the rotor to the outlet duct 58 While both the gas and the air flow peripherally in the direction of the rotor, while in the grooves, it will be evident from Fig. 1 that the general flow relation between the two fluids is counterflow, the hottest gas being in heat exchange relation with that part of the rotor in contact with the hottest air and the coolest gas being in heat exchange relation with that part of the rotor to which the coolest entering air is admitted.

The action of the apparatus has been described above as applied to the preheating of combustion air by combustion gases and in such applications it is ordinarily preferable to pass the gases through the external grooves of the drums and the air through the internal grooves since the volume of gas passing through the apparatus in such applications is usually larger than the volume of air. Also, the external groove structure is more readily cleaned of solids such as soot and ash deposited Insofar as the basic operation is concerned, it will, however, be evident that if desired the hot medium may be passed through the internal grooves, and the medium to be heated passed through the external grooves, the choice being governed by the nature and characteristics of the media employed and the desired heat exchange between tained. Also, by limiting the uninterrupted flow of the fluids in individual grooves to sectors of predetermined length, the character of the flow can be controlled so as to produce a high rate of heat transfer not only because of high relative velocity, but also because of the fact that the absolute velocity of the fluid can be maintained at a sufiiciently low value to prevent turbulence of an undesired nature. If the velocity is sufliciently low, generally laminar flow can be maintained except at the surface layers where small secondary eddies rotating about axes normal to the general line of flow are produced. These eddies are desirable from the standpoint of heat transfer and do not create much resistance to flow, and since the grooves are preferably generally relatively deep and narrow, the eddy like turbulence of the surface layers is sufficient to bring most of the fiuid the rate of heat transfer accordingly reduced, but also there may be induced a rotary turbulence in the plane of rotation, which is undesirable. Further, by ejecting the fluid from the grooves after a predetermined length of travel and transferring the fluid to another set of grooves, it is further ensured that all of the fluid in a t given stream or ct-numb is brought into intimate heat exchange relation with heat transfer surfce. The number, spacing and cross sectional shape and area of the grooves may vary widely depending upon the nature of the heat exchange conditions to be met, the character of the fluid or fluids involved, entering temperatures and desired leaving temperatures, volumes to be handled, pressures and other specific factors. These factors will also aifect the length of the paths of flow of the streams in individual grooves, the grouping of the grams, which may, for example be such in an extreme ease, that each group may consist of but a single groove. In the embodiment being described the grooves have, for the sake of simplicity, been shown of equal cross section between equally spaced ribs. It will be evident, however,

that in cases where a gas is materially cooled and contraots materially during its flow through the apparatus, and it is desired to maintain a relatively constant velocity of flow, the ribs may be spaced closer together at the colder end than at. the hot end to compensate for the contraction. 7 h v Also, in apparatus where the path of flow isrelatively long and through a large number of groove sectors, the cumulative eitect of the friction may result in a higher than desired velocity through the apparatus when n a given fluid column travels in all cases through the grooves in the direction ofmovement of the rotor, as illustrated for xample" in Fig. 4. This condition can readily be avoided by apparatus operative to reverse the direction of flow in any selected number of sectors'so that in such sectors the fluid now in the grooves is counter to the direction of movement of the rotor andgin Figs. 5 to 7, one suitable embodiment of apparatus for effecting this is'illustrated. In substantially allparticulars the arrangement is the same as that previously described and cor responding parts are correspondingly numbered. The difference between the constructions is that for any se lectedspace, or spaces, as shown more particularly in Figs. 5 and 7, the direction of slant of the oblique por: tion 78 of the partition members 76 is reversed as indicated at7$riso that if we compare Figs. 3 and 5, and Figs. 4 and 7, respectively; it will be seen that the fluid flowing from the grooves through outlet port 84a, flows axially in the arrangementof Figs. 5 and 7 to inlet port 82b, which is in effect an axial continuation of the outlet port 84a. From inlet port 82b, the fluid flows through the grooves counter to the direction of rotor movement to outlet port 8412 which in this embodiment is on the same side of the cover member 74 as the

inlet ports

82 and 82a. In the embodiment illustrated, the counter flow is carried through a plurality of groups. of grooves-,.

hut it will be evident that this specificarrangement may be varied at will with respect to the number and arrangemeat of passes through the grooves in which the fluid flows counter to the directionnof rotor rotation, as come pared with the passes in which the flow is in the same direction. In any case, it will be apparent that in those passes where the fiowis counter, to the direction of rotor rotation, friction will exert a decelerating effect and by proper selection for a given design the rate of flow of fluid through theapparatus as a whole may readily be governed to suit the specific conditions. I n H n e .As noted above, the grooves are preferably relatively deep and narrow and the ratio of depth to width of the grooves may in many, instances be, as much as tengto one, or even materially greater. With such relatively deep and narrow. grooves, thejrate of heat transfer in the grooves is improved by the provision of auxiliary guide fingers shown at 102 and .104 in Fig. 2, which fingers extend only partially oi the full depth of the groovesand are located so that they serve to divide and guide the fluid entering and leaving the groove sectors through the respective. inlet and outlet ports. These fingers may beparts er saint, like member similar a; the berfle menses 70 aaaslrpporteatn anysui tablefashidn semis 6 as parish: the siatieaary lsfrncfiire, it being noted that in the present embodiment these guide members rnust be radially spaced m the cylindrical walls 32 an as re; spectively, of the stationary structure since the fluid must flow" across the tops of these guide members :in its flow' between the several ports and the transfer passages. For the sake of clarity, these guide members have been shown, in phantom viewin Fig. 3 and have been omitted from the showing in Fig. 4 The number and specific arrangements of the guide fingers at any particular port or series of ports may be varied to suit the individual conditions required in order to obtain a more advan tageous distribution of flow of the fluid throughout the a depth or the groove. l v

Also in certain instances it may be desirable to provide inlet ports of greater peripheral extent than that of theoiitlet ports, rather than ports of equal area as shown in the apparatus illustrated. n e

It will further be apparent from the nature of the ap paratusfdescribed that in addition to acting as a heat exchanger the apparatus may also provide all of the power required to create the flow of the fluid media and for example when used as an air preheater may provide the only means required to produce the necessary forced draftflow of the combustion air and also the force required to exhaust the spent combustion gases". Thii's th apparatus may enable separate forced draft and exhaust fans to be eliminated entirely, or 'meterially reduce the power requirements 'for such fans by acting as a compound "fan for both purposes. v

V Inboth of the embodiments above described, the stationarystrlicture is arranged so that the fluid columns flow in generan' axial directionfromendto endof the rotors. This arrangement, however, may be varied and in rigs; s to 10, another embodiment is'illustrated in which a different path of flow -forthe air columns is provided. In this example, the general arrangement of rotor and stationary structure are as shown in Fig. 1, and corresponding parts are similarly designated. In the present construction, the bafiie members providing the fingers extending into the grooves, do not extend from end to end of the rotor but are peripherally offset as indicated at 7021-, 7%, 700-, 7021 and a in Fig. '8. Each of these offset bafiles is coextensive with a group of grooves, the number of which may be chosen at Will, axially coextensive with the baffles. A series .of sets of box like

cover members

106 and 108, the botto'rns'of which provide respectively the cover members 74 and SSlocated respectivelyover the inner and outer rotor grooves. The end walls 110 and 112 of these box like rnernbers define peripherally the limits of the inlet outlet ports communicating with the groove sectors while tite -side walls 1'14'and 11 6 define the aXial extent or ports. Due to "the peripherally oflset relation *or adjacent ones of thefseveral series of the box members "the outlet sns'cdmmunicae with one 'group of grooves which are axially in communicati n jwith the inlet ports or the next adjacent group ofg'rdoves by way of axially extending transfer passages 118, each defined by a bathe member, the'side walls of two of the adjacent box mem bers, and theinner or

outer casing wall

32 or 38 as the case may be.

-FrornFifg. 8, the natu're of the flow of the fluid colurnns is indicated by arrows 120, -frdm which it will be seen that the several columns progress successively 'tlirdugh peripherally ofis'et sectors of axiallysuccess'ive groups of groans, the general direction of the path of 'flow 'bein'g" helical around the rotor drum rather than genennyyaiauy thereof, as in the arrangement shown in Fig. 1.

1 "In the present arrangement, auxiliary. guide fingers 10': end 104 are shdw'nand it win be noted that in the present construction these guide fingers can be extended support by the

casing parts

38 and 32, respectively,

sinee the fl ow through the transfer passage is lengthwise of these guide members rather than across the tops of them, as in the previously described embodiments.

In the arrangement shown in Fig. 8, the fluid flow iii the grooves is always in the direction of movement of the rotor and for reasons previously explained it may be desirable to provide for counter flow of the fluid in one or more groups of grooves. An arrangement for effecting this is shown in Fig. 11, wherein certain of the baflie members 70 and box members 106 are shown in offset relation such that the direction of flow of the fluid columns is peripherally reversed as indicated by arrows 122.

In Figs. 12 and 13, the invention is shown embodied in a rotor of different form than that shown in the previously described embodiments.

In this form of the apparatus the rotor shaft 200 carries a radially extending disc 202 which in turns supports a multiplicity of radially spaced concentric cylindrical ribs 204 and 206 on the opposite sides of the disc respectively and providing a multiplicity of annular cylindrical channels of groove like form 208 and 210, respectively. The stationary structure indicated at 212 comprises an outer cylindrical shell 214 between which and disc 202 a seal diagrammatically indicated at 216 is provided, and end walls 218 and 220. The structure forms an inlet duct 222 for fluid such as air to be heated, which communicates with the annular space 224 immediately around the rotorshaft on one side of the disc 202. The structure further provides an outlet duct 226 having an annular portion 228 extending around the periphery of the casing adjacent to the end wall 220 and the flow of-air from duct 222 to 226 is generally outward from the central inlet space 224 to the periphery of the rotor duct and the annular duct 228. The end wall 220 carries a plurality of sets of bafile members 230 which provide fingers 232 extending into and substantially damming the grooves 208, the sets of baflles at the same radius being peripherally offset with respect to adjacent sets of baflles at greater radius, as seen more clearly in Fig. 13, and between adjacent baflles of each set are box like cover members 234 which are likewise in sets, with adjacent sets of different radius peripherally offset relative to each other.

These cover members 234 are similar in form and function to the box like cover members illustrated in Fig. 8, and have side walls defining inlet and outlet ports 236 and 238 communicating with the sectors of the grooves between adjacent baffles of the same set. As further will'be seen from Fig. 13, the relative periphcral location of the cover members of the adjacent sets is such that the inlet ports leading to one group of grooves'is radially in registry with a group of outlet ports leading from a radially adjacent set of grooves, to provide radially extending transfer passages 240 for carrying fluid discharged from the sectors of one group of grooves to peripherally offset sectors of the adjacent group of grooves lying radially outside the group from which the fluid is discharged.

By comparison of Figs. 13 and 8, it will be evident that the arrangement is the same in principle in both, the difference being that the several columns of fluid in the arrangement of Fig. 13 flow in generally spiral direction radially of the rotor, as indicated by arrows 242, instead of generally helically of thevlength of the rotor as in the construction of Fig. 8.

In the present embodiment the structure provides an inlet duct 244 for fluid, such as combustion gases, this duct having an annular portion 246 for distributing the gas to the radially outermost grooves. The casing wall 218 carries baffles 248 provided with fingers 250 extending into grooves 210 and box like cover members 252, similar to the cover members 234 carried by the end wall 220. The arrangement of these baflles and cover members is similar to thatof the structure shown in Fig, 13 and need not be described in detail, the dif ference between the arrangement at the two sides of the disc 202 being that in one case the fluid flow is in generally outward direction while in the other case the flow is in. generally spiral inward direction to the outlet duct 254. As in the previous embodiments, this arrangement provides for counter flow. Preferably, as described, the fluid to be heated, which exands, flows outwardly, while the heating fluid which contracts due to being cooled, flows inwardly.

It will be evident that in the embodiment just described, the arrangement of the baflles and the cover members may be made so as to provide flow of fluid counter to the direction of rotation of the rotor in as many of the sectors as is desired in order to provide the desired rate of flow. Variation in relative size of inlet and outlet ports and the provision of auxiliary guide fingers are, for the sakepof clarity, omitted from the figures. Other features of design previously described may equally well be applied to the embodiment under con sideration.

In all of the previously described embodiments, movement of the rotating body is utilized to induce flow of the fluid or fluids and the rotary movement of the fluid and solid bodies is concurrent.

However, the basic principles of the invention are equally applicable, with improved results, in cases where in order to secure an even higher rate of heat transfer between fluid and solid bodies, the fluid is forced by mechanical means such as a fan to flow counter to the direction of rotation of the solid body. For such a method of operation, it is evident that the structures hereinbefore described, except for the modifications illustrated in Figs. 5, 7 and 11, are suitable without change, it only being required that appropriate fan or equivalent means of any desired conventional kind be provided to effect the necessary flow of fluid in the direction opposite that indicated by the arrows in the several figures.

Even the modifications of Figs. 5, 7 and 11 would be operative with forced flow counter to the direction of rotation of the solid body, but in such cases the reversal of flow at intermediate places effected by these structures would serve no useful purpose and would in fact be detrimental.

superficially, it might appear that forced flow counter to the direction of rotation of the solid body is at variance with the basic principles of the invention as hereinbefore described, but such is not the case, since high relative velocities between the heat exchanging bodies may be secured with relatively low absolute velocities of the fluid bodies. Low absolute velocity of the fluid avoids creating the undesirable turbulent rotary flow of the fluid in the plane of rotation hereinbefore discussed, even though the relative velocity between the fluid and solid bodies is high. This, together with the fact that only relatively low absolute velocity of the fluid must be generated, insures a relatively very low power requirement for the rate of heat exchange obtained.

While for purposes of explaining the invention, apparatus has been shown for heat exchange between two gaseous fluids both of which are caused to flow in accordance with the novel principles of the invention, it will be understood that such principles are equally applicable for heat exchange between gaseous and liquid fluids, be-

c tween different liquids, and for heat transfer between a fluid and a solid body. Further, it will be apparent that if desired one of the two fluids between which heat is exchanged may flow in conventional fashion in heat exchange relation with the solid body which may have plain surface or extended surface of known kind in heat exchange with such fluid. a

It is accordingly to be understood that within the scope of the invention many variations in design and arrangement are possible and that certain features herein disjclosed may be used to the exclusion of others, the in vention being definedby and including all apparatus within the purview of the appended claims.

What is claimed: V 1. Heat exchange apparatus comprising a rotor having a plurality of transverse parallel ribs providing a multiplicityof open peripherally continuous circulargroovelike channels, concentric with the axis of rotation of the rotor for flow of fluid in paths of flow in said chan nels lying in planes normal to said axis and stationary structure including inletand outlet openings for fluid and having a wall concentric with and cooperating with said rotor to provide for flow of said fluid between said openings through said channels inheat exchange relation with the rotor, said structure including longitudinal baflies, each balfle having onelongitudinal edge abutting said wall and the opposite longitudinal edge having fingers extending into and obstructing said channels, longitudinally extending cover means for said channels disposed between adjacent said bafiles, means forming transfer pas: r

sages connecting different channels at' places adjacentlto sai'd baflcles and at opposite sides of said cover means for new offiuid progressively through different channels and means to drive said rotor.

2. Heat exchange apparatus comprising a rotor having a pluralityof transverse parallel ribs providing a multiplicity of open peripherally continuous circular groovelike channels concentric with the axisof rotation of the rotor for flow of fluid in paths of flow in said channels lying in planes normal to said axis and stationary strueture including inlet and outlet openings for fluid and having a wall concentric with and cooperating with'said rotor to provide for flow of said fluid between said open ings through said channels inheat exchange relation with said rotor, said structure including a plurality of peripherally spaced longitudinal balfles, each baflle having one longitudinal edge abutting said wall and the opposite longitudinal edge having fingers extending into and obstructing said channels to provide a plurality of channel sections in each channel, longitudinally extending cover meahs fors a'id channels disposed peripherally between adjacent baflles, means forming transfer passages connecting different sections of diiierent channelsjat places adjacent to said balfles and at opposite sides of said cover means for new of fluid progressively through sections of different channels and means to drive said rotor.

3. Heat exchange apparatus comprising a rotor having a "plurality of transverse parallel ribs providing a multiplicity of op'en peripherally continuous circular groovelike channels concentric withthe axis of rotationof the rotor for flow of fluid in paths of flow in said channels lying in planes normal to said axis and stationary structure including inlet and outlet openings for fluid and having a wall concentric with and cooperating with said rotor to provide for flow of said fluid between said openings through said channels in heat exchange relation with the rotor, said structure including longitudinal baffle members, each baifle member having one longitudinal edge abutting said Wall and the opposite longitudinal edge having a series of axial aligned fingers providing bafiles extending into and obstructing a series of said channels, longitudinally extending cover means for said channels disposed peripherally between and peripherally spaced from adjacent baflies to provide ports communicating with the channels adjacent the baflles, means forming transfer passages defined in part by said cover means, connecting ports with diflierent channels at opposite sides of said cover means for flow of fluid progressively through the several channels and means to drive said rotor.

4. Heat exchange apparatus comprising a rotor having a plurality of transverse parallel ribs providing a multiplicity of open peripherally continuous circular groovelike channels concentric with the axis of rotation of the rotor for flow of fluid in paths of flow in said channels lying in planes normal to said axis and stationary struceerie-r6 ture including inlet an outlet opening; forfluid and ing a wall concentric with and coeperating with said ro' tor to provide for flow or said fluid between said openings through said channels in heat exchange relation with the rotor, said structure including a plurality of longitudinally peripherally spaced baifles, each bane liav ing one longitudinal edge abutting said wall and the op: posite, longitudinal edge having axially aligned fingers providing baflles extending into and obstructing said chan: nels, longitudinally extending cover means for said chan nels disposed peripherally between and peripherally spaced from adjacent baflles to provide ports communi catingwith the channels adjacent the baflles, means including said cover means and partitions disposed oblique: ly with respect to the planes of the channels forming oblique transfer passages connecting ports communicating with certain ofsaid channels at oneside of said cov er means with ports communicating with other channels at the other side of said cover means and :means to drive saidrotor. H U...

5 Heat exchange apparatus comprising a rotor having a plurality of transverse parallel ribs providing a multiplicity of open peripherally continuous circular groovelikechannels concentric with the axis of rotation of the rotor for flow of fluid in paths of flow in said channels lying in planes normal to said axis and stationary structure including inlet and outlet openings for fluid and having a wall concentric with and cooperating with said rotor to provide for flow of said fluid between said openings through said channels inheat exchange relation with said rotor, said structure including a plurality of longitudinal peripherally spaced sets of baffles, said baffle having one longitudinal edge abutting said wall and the opposite longitudinal edge having fingers extending into and obstructing said channels, the baflles of one set being peripherally offset with respect to the baflies of the adjacent sets, longitudinally extending cover means for said channel's disposed peripherally between andperipherally spaced from adjacent battles of each set to provide port's communicating with the channels adjacent the baflies, means forming transfer passages connecting ports corn municating with different channels at opposite sides of 'said cover means for .flow of fluid progressively through dilfe'rent channels and means to drive said rotor.

6. Heat exchange apparatus comprising a rotor having a plurality of transverse parallel ribs providing a multiplicity of open peripherally continuous circular groove-hire channels concentric with the axis of rotation of the rotor for flow of fluidin paths of flow in said channels lying in planes normal to said axis and stationary structure including inlet and outlet openings for fluid and having a wall concentric with and cooperating with said rotor to provide for flow of said fluid between said opening through said channels in heat exchange relation with said rotor, said structure including a plurality of longitudinal peripherally spaced sets of bafiles, said baffies having one longitudinal edge abutting said wall and the opposite longitudinal edge having fingers extending into and obstructing said channels, the baffles of one set being peripherally olfset with respect to the baflles of the adjacent sets, longitudinally extending cover means for said channels disposed peripherally between and peripherally spaced from adjacent baflles of each set' to provide ports communicating with the channels adjacent the baflles, means forming transfer passages connecting ports communicating with diflerent channels at opposite sides of said cover means for flow of fluid progressively through diflerent channels, at least certain of said transfer passages connecting ports situated ahead of said battles with ports situated behind adjacent baflles, considered in the direction of rotation of the rotor and means to drive said rotor.

7. Heat exchange apparatus comprising a rotor having a wall and a plurality of transverse ribs extending from the opposite sides of said wall to provide on each side. of the wall a series of peripherally vcontinuous open groove-like circular channels concentric with the axis of rotation of the rotor, stationary means including inlet and outlet openings for fluid and having walls concentric with and cooperating with said rotor to provide for flow of fluid in paths of flow in said channels between said openings lying in planes normal to said axis, said stationary means including longitudinal baflles, certain of said baflles having one longitudinal edge abutting one of said last named walls and the other of said baflles having one longitudinal edge abutting the other of said last named walls and the opposite longitudinal edges of said baflles having fingers extending into and obstructing said channels, longitudinally extending cover means for said channels disposed between adjacent bafiles, means forming transfer passages connecting difierent channels at places adjacent to said baflles and at opposite sides of said cover means for flow of fluid progressively through different channels on each side of said first named wall and means to drive said rotor.

8. Heat exchange apparatus comprising a rotor hav ing a wall and a plurality of transverse ribs extending from the opposite sides of said wall to provide on each side of the wall a series of peripherally continuous open groove-like circular channels concentric with the axis of rotation of the rotor, stationary means including inlet and outlet openings for fluid and having walls concentric with and cooperating with said rotor to provide for flow of fluid in paths of flow in said channels between said openings lying in planes normal to said axis, said stationary means including a plurality of longitudinal peripherally spaced baffles, certain of said baffles having one longitudinal edge abutting one of said last named walls and the other of said bafiies having one longitudinal edge abutting the other of said last named walls and the opposite longitudinal edges of said baflies having fingers extending into and obstructing each of said channels to divide the same into a plurality of sections, longitudinally extending cover means for said channels disposed between adjacent baflles, means forming transfer passages connecting different sections of said channels at places adjacent to said bafiles and at opposite sides of said cover means for flow of fluid in each side of said first named wall progressively through peripherally displaced sections of diflerent channels on the same side of said first named wall and means to drive said rotor.

9. Heat exchange apparatus comprising a rotor drum having a plurality of transverse open circular groovelike channels concentric with the axis of rotation of the drum and providing for flow of fluid in paths of flow 12 in said channels lying in planes normally to said axis, said channels comprising a first series of inner channels extending radially inwardly from the wall of the drum and a second series of outer channels extending radially outwardly from the wall of the drum with said wall defining the bottoms of both series of channels, stationary structure including inlet and outlet openings for fluid and having inner and outer walls concentric with and cooperating with said drum to provide for flow of fluid in paths of flow in said inner and outer channels between said openings, said stationary structure including longitudinal inner and outer bafiles, said inner baflles having one longitudinal edge abutting said inner wall and the opposite longitudinal edge having fingers extending into and obstructing said inner channels, said outer baflles having one longitudinal edge abutting said outer wall and the opposite longitudinal edge having fingers extending into and obstructing said outer channels, longitudinally extending inner and outer cover members for said inner and outer channels disposed between adjacent inner baffles and between adjacent outer baflles,

means providing inner transfer passages connecting different inner channels at places adjacent said inner batfles at opposite sides of said inner cover means for flow of a first fluid medium progressively through different channels of said first series, means providing outer transfer passages connecting dilferent outer channels at places adjacent said outer baflles at opposite sides of said outer cover means for flow of a second fluid medium progressively through difierent channels of said second series and means to drive said rotor drum.

10. A structure as defined in claim 9 in which said transfer passages are arranged for flow of each of the fluids from channel to channel progressively of the length of the drum and in countercurrent relation with respect to each other lengthwise of the drum.

References Cited in the file of this patent UNITED STATES PATENTS 1,639,051 Munday Aug. 16, 1927 1,698,313 Luther Jan. 8, 1929 21,897,613 Jensen Feb.-14, 1933 1,914,084 Ellis et al. June 13, 1933 2,369,993 Turner Feb. 20, 1945 2,402,307 Vannerus June 18, 1946 V FOREIGN PATENTS 252,373 Great Britain Apr. 14, 1927 500,389 Great Britain Feb. 8, 1939 545,782 Germany Mar. 5, 1932