US2693942A

US2693942A - Heat transfer apparatus

Info

Publication number: US2693942A
Application number: US292403A
Authority: US
Inventors: John R Guala
Original assignee: Gulf Oil Corp
Current assignee: Gulf Oil Corp
Priority date: 1952-06-09
Filing date: 1952-06-09
Publication date: 1954-11-09
Anticipated expiration: 1971-11-09

Description

Nov. 9, 1954 J. R. GUALA 2,693,942

HEAT TRANSFER APPARATUS Filed June 9, 1952 2 Sheets-Sheet l JNVEN TOR. J HN R- GUALE HIS HTTORNEY Nov. 9, 1954 Filed June 9, 1952 J. R. GUALA HEAT TRANSFER APPARATUS 2 Sheets-Sheet 2 INVENTOR. JOflN -R- iana i3 ATTORNEY United States Patent 6 2,693,942 HEAT TRANSFER APPARATUS John R. Guala, Upper Darby, Pa., assignor to Gulf .Oil

Corporation, Pittsburgh, Pa., a corporation of Pennsylvania App ica n u e 9, i N0-292A03 .1 Cla m .(Cl- 7-224) This i en n re a s to a :baiile y tem fer h at change equipment, and more specifically to a system comprising a series of plates extending part way across a. tube bank at an angle" to the longitudinal axis of the heat e c an e uipment and il l i he 19 i e t th u d w s' s th 'thhe h'a bli i' li y f' e an l sl helical streams. w

A common arrangement of baffles in heat exchange equipment is a succession of ha file plates extending part way across the shell perpendicular to the longitudinal axis of the shell, with alternate baffle plates extending from opposite sides of the shell.

Another common arrangement is a number of hafile p s placed p l to ne hethe eh Pa allel to h l n l axis o the sh ll wi h eh rheiehl tee extending from opposite ends of the shell.

he t e of beii s cau h h re ta e t he h of h fl i d m d um, eahee hi h vloca ize iee i e i n f a yl u ih ma eria tha ma he ha ri d .ihth eh l flui or m y h p p ta d th eiiemrah h y era] other practical disadvaatages.

Q fihd i li f h t asi hies ehs 29th hen; the st ndh of p s u e s nd he t t a sient? ei th fluid outside of the tubes in a diiferent manner. Ihay e invented a s e of effi he e y efluid i .s, e e e e tu es in a p ura t Q hel ca Paths, a d in which the pressure in the various helical paths will automatically equalize.

It is an object of this i n i tomevid a-he exchange a p t of t sh and ube ;..type .wh eh eif g s a t a sf n a m re te fie ehtmehh rt ah he e to ore.

Another object of this invention is to provide a shell n u e yp hea ch er in w ch hefiu d outside the tubes is directed in separate but communicating. paths throughout the shell.

An th r bi e o h i ht hi t provide a bafiie construction for shell and tube type heat exchangers which prevents the formation of stagnant .pockets'in he pa h of th flui th ou th shell- A particular object of this invention is Provide an apparatus which contributes to the equalization of, pressk lirel between he parallel streams ,of fluid within {the 5 el A sfll further object of this invention is -;to provide a gbafile structure which substantially reduces. scale and sediment deposits.

The foregoing and other objects which :will the apparent from the following descriptionare obtained by the invention disclosed and claimed herein.

Referring to the accompanying drawings,

Figure l isa longitudinal sectional view of. a heat .exchanger fitted with the baffie system which .constitutes my invention;

Figure 2 is a longitudinal sectional ,view similar to Figure 1, but .the arrangement of'the bafile plates and their supporting means has beenernphasized in this view by omitting the exchanger tubes;

.Figure 3 vis an individual plate of a baflie, -of the same design as those shown in Figures 1 and 2';

Figure 4 is a cross sectional view taken on line I I of Figure 1; and

Figures 5, 6, 7, 8 and;9 are specific forms of bafile plates within my invention, all being somewhat different fromthe specifieform shown inFigures l, 2, 3 and'4, andveach diiferent from one another, the distinction being obvious from -the e" CC of these embodiments .pf invention be io nd h s ar i e i e e ie' r e v' I fastened in o the tube sheets byheing rolled ther .Y bei i hdi ue y k s by ih'y'td 5 f tional means of ia'st'en ng'; Headers sitil e'd'at"opp.o sitee1ids of 'shell'l, t: [ts and headersare.fastened'togetheri v A 2;. HeaderslT and .19 provide inean connections 2'6 'a'n'd 27:,[fof introducing awaythe fluid which is to be'passed'throii v This fluid i 's" reter'r'ed to hereinafter" as t ll. 1,. Headers 2 and 3"ai1 sirnilaIr'lY p'r'videdfor in od h ee ilh t h awayhe id w e i be h eil'h si e thel h Th s i d is e e e'f e ei f ed' e' as ishell fluid The num er, iiia'metje and length of tubes v I 1 I in the heat'exchange ppar t ses well'af s the diameter'of the shell ljwill" beya'r iedtom t requirements of individualcas'es'. Forip u'r'poses tration, a simple foim'o'f heateXc anger has be Sh in 'Fig'urejl, "Additional 'feat'ures'such as the fleet ng head fco'uld' of coursdbe included', but hayeb'fe'n omitted for'sirnplicity.of'presentation.

Th 'eu h'eh ihe len th o 'sh l 1 I plac a ue sio o he ii e h hs ih 'e weh e 'e The ndi a 5 hi mer l'sjfi h E Th "ihs, P a e hf the b fl f' i illustrated'in Figuresl and 2, d [of ,thespecific desig' ri h n i fi mps u "Inadditioh' to tubes 5 eing held in PlQQe by gubesheets 14'; "the relative p es" ens of tubes? openings ;8 positioned in alignment with the holes t p i hes ee il bl fii i y i t i i1 1 h 1 r 4.," 1.. c he in i idu l P a d t e ehee e y be the" exchar ge'rl'shell'l'are bofund ogether ""th e 1 spatial relationship and intof'a' unitaryconstruct riib'y l hs' dihe i i i 9- he "s r s :9 i T- ie theiplates,,a,t',fslots '10, also servean' additional purpose in that they are positioned to pass through the' at peripheral areas that r' i'not offsuflicientsize ;t

modae ub s Z h ehsi hel ere i nel thrq igh'. these. nefiective' 'aones. L Theffshell' fluid is given a helicaln otidn .byfthelb ffle Q Onstru'ctio Thei e disclosedandflclaimed, and these ISt'ripsIQ jposit Jwda's statedgl block aiiytendency of the shell fluid to pr prentially' seek a pathalong'theshellwall. "Referring to jFigure' 3 :a: single bafl e .P1ate.. is,show .as 6. Thispl a'te is a s :g'rnei:1t.oiari e'llipse'jand the" axis 'av a and the ,minora gis b b'thereof are i d It gwillhe seen'tha't plate .6 is 'a' segment fora ellip consisting .of.,an ,entirefsernicllipse together with an {eittension or step c, d, e,.f,"c. Two of these plates, 6 and '7, are fitted together, as shown in Figure 2, ltoiformaa bafile, and they are there shownpositioned in thefube shell with their planes fat an angle of lappr'oximatelyAfi to the longtiudinal axis of the shell and 'at ari an'gle'lof approximatelyl to .each other'l A n angle lyingapprogiimatelywitliin the range io ffromfl' 5 to '15: between vthe Plate r h in i idua ete l n e en tmhnai axis of thershell ordinarily be foundmost efiective, the preciseangle in any particular case beingjcontrolled by .eeh i e te eh su h a she -f u d vel y ;he .'e ehang te qu n :e s e fl i avai ab im ih or'minimum permissible temperature cha'nge, ,p ermissibl e pressure drop, etc. The width of the semi-elliptic part of plate 6 is one-half .of.the, internal diameter of shell ,1, or very slightly less, and Ithe two plates constituting a baffie ,arelposit'ioned alongside 'of one another with'Itheir minor axes in longitudinal alignment, jwith' fthe'ir' respective planes at' an angle ,to 'o'nefanother, and w'th' e eheieh f rea Plate xtendin eerl e patelishellxl is a eylihdi ee shel .ahd iiwil heh ses ary because the plates are positioned at an angle other than 90 to the longitudinal axis of the shell that they have greater length than the diameter of the shell. The individual plates will be segments of ellipses, the minor axes of which ellipses will equal the internal diameter of the shell 1, and the major axes of which will be such that the plates will abut the inside of the shell at all points along their curved edge. For instance, if the angle of the plates to the axis of the shell is a 45 angle, the major axis of the elliptic plate will be 1.414 times the internal diameter of the cylindrical shell 1. For any angle at which it is desired to position the plates, the length will be arrived at by multiplying the internal diameter of the shell by the cosecant of the proposed angle between the individual plates and the longitudinal axis of shell 1. Each plate 6 is pierced with holes 8 to permit the insertion therethrough of the tubes of the heat exchanger. The plate is also provided with slots 10 to receive supporting strips 9.

It would be possible to make baffles from two plates which were exact semi-ellipses, out along the major axis of the ellipse, but that would permit a certain amount of shell fluid to short-circuit and by-pass many of the tubes. For that reason the plates 6 carry extension areas c, d, e, f, c to direct the shell fluid over the maximum number of tubes and prevent its snaking along the length of the heat exchanger close to the axis thereof. This provision of plates with extensions c, d, e, c is a fundamental feature of this invention. Another embodiment of this feature will be described in connection with Figure 5. As

respects plates

6, 7 and 25, the extensions on the plates protrude beyond the major axis of the ellipse by a substantially uniform dimension throughout their length, this dimension being not substantially less than one-twentieth or more than one-third of the length of the minor axis of the ellipse.

Figure 4, which is a sectional view on line II of Figure 1, shows the overlapping of the extensions of the two plates which constitute a baffle.

Figure 5 shows an embodiment of my invention which diifers somewhat from that shown in Figure 3. It involves the use of plates instead of plates 6. In Figure 5 the individual plates of the baffles are again segments of an ellipse, but they differ from plate 6 shown in Figure 3 in that they have two extensions, 0, d, e, f, c and c", g, h, k, c, instead of one such extension as shown in Figure 3. Plate 25 having two extensions, must have a notch therebetween to permit the companion plates of a baffle to fit together. This notch d, c, c", g is of a width to permit interlocking of companion plates and it extends inwardly from the outside edge of the extension to the major axis of the ellipse. Plate 25 further reduces the tendency of the shell fluid to seek a path down the axis of the shell. It also permits strong interlocking of the two companion paltes of a baffle.

Figures 6 and 7 show two related embodiments of my invention in which the segments of the ellipse include a semi-ellipse lying altogether on one side of the major axis together with an extension beyond the major axis on either one side or both sides of the minor axis. The embodiments shown in these two figures have extensions which are out along radii of the ellipses, the form shown in Figure 6 having an extension along onehalf its length, and the form shown in Figure 7 having an extension along each half of its length. In the embodiment of my invention shown in Figure 6, the plate 28 is a segment on an ellipse. The major axis aa is indicated on the drawing, and so also the minor axis bb, the intersection of the two axes being indicated at 0. Plate 28 is out along the major axis aa from c to k, thence around the periphery of the ellipse for a full 180 and further by distance f-e, and in a straight line from e to c.

The form of baffle plate 29 shown in Figure 7 carries an extension beyond the major axis aa on each side of intersection c.

In this case the baffle plate 29 is a segment of an ellipse, and the major axis is indicated at aa, the minor axis at b-b, and the intersection of these two axes is indicated at 0. Plate 29 is cut in a straight line along line c-h, from h along an elliptic periphery across major axis a-a, 180 therebeyond to major axis a-a again, and then through the extension width f-e, and thence in a straight line e-c. The extension c-k hc may or may not be equal in dimension to extension c-f-ec.

CIl

In both

plates

28 and 29, the individual extensions may "havean area' up to as much as approximately 80 per cent of the area of a quadrant of the ellipse. This same proportion holds, in fact, for the extension of the plates shown in Figures 3, 5, 6, 7, 8 and 9.

Figures 8 and 9 show two related embodiments of my invention in which the segments of the ellipse include a semi-ellipse, lying altogether on one side of the major axis, together with an extension beyond the major axis on either one side or both sides of the minor axis- The embodiments shown in these two figures have extensions which are cut in a straight line from the intersections of the major axis with the elliptic periphery to a point on the minor axis which is somewhat removed from the major axis. In the embodiments of my invention shown in Figures 8 and 9, the

plates

30 and 31 are segments of an ellipse. In each case the major axis a-a is indicated on the drawing, and so also the minor axis b--b. Plate 30, shown in Figure 8 is cut in a straight line from each of the two intersections of the elliptic periphery with major axis zza to a point on the minor axis out beyond the major axis, to produce somewhat more than a semi-ellipse, and a slot d, c, c, g is then cut back along the minor axis to the major axis in order that two such plates, when used together to form a baffle, will abut at the intersections of their respective major and minor axes. Figure 9 shows plate 31, with an extension 0, k, d, 0 extending out beyond the major axis only on one side of the minor axis. The triangular extensions depicted in Figures 8 and 9 are especially effective in preventing the shell fluid from preferentially channeling along the longitudinal axis oi the cylindric heat exchange device in which the baifles are used.

The various shapes of plates depicted in Figures 3, 5, 6, 7, 8 and 9 all have particular advantages according to the specific situation in which they are used, the disposition of the shell fluid to preferentially channel through some minor portion of the cross section of the heat-exchange device, the permissible pressure drop, etc.

The function of a tubular heat exchanger is to transfer heat between two fluids, one of which passes through the tubes and the other of which passes outside of the tubes and within the walls of the exchanger shell. Such an apparatus permits interchange of heat between the two fluids while preventing any direct contact or mixture of the two fluids. This invention is not directed to the handling of the fluid passing through the tubes: it concerns the handling of the shell fluid, i. e., the fluid which passes outside of the tubes and within the exchanger shell.

' In this invention shell fluid is introduced through flanged inlet 2 in such manner as to pass through the shell 1 and to effect during such passage the maximum amount of heat transfer for the heat transfer area availa e.

The helical path of the shell fluid in its passage through the heat exchanger shell results from the interrelation, spatially, of successive baffles from the inlet end of the exchanger to the outlet end of the exchanger. As shown in Figures 1 and 2, my invention involves the use of a series of baffles, each baffle comprising two plates 6 and 7, each baffle in a series is positioned closely adjacent to the baffle that precedes it in the series and to the baffle that follows it in the series; the battles in a series are positioned with no substantial angular rotation between successive baflles, whereby the planes of corresponding plates in successive baflles assume parallel position and, with their companion plates, form two continuous channels of somewhat helical form from one end of the heat exchanger shell to the other end thereof. As will be obvious from Figures 1 and 2, the opposed planes of the two plates of the first baffle divide the stream of shell fluid into two separate streams which pass along successive baffles from end to end of the exchanger as parallel streams. Instead of plates 6 and 7, as shown in Figures 1 and 2, the plates may be of the conformation shown in Figures 5, 6, 7, 8 and 9.

Referring to Figure l the stream of shell fluid entering a heat exchanger fitted with my system of bathing will be directed, in substantially equal parts, across the nearer end of each of the two plates 6 and 7 constituting the first balfle, then in a somewhat circular or helical course along the plate, this curving course being centered around the longitudinal axis of the exchanger I being pierced t hell.- When. he stream P sses oil of th sl te it pa ses. a channel term d by he unslsr eid "vi he adj ent pl te of the. firs aifie an the. op .Sti? or a pl e of e nd b fil Specifi ally, the tream .11.} ate y a dot d l e a identified y nume al-1.1 will pass over plate 6 and then into a channel between

plates

7 and 15 and on into a channel between plates 14 and 20. The course of the second stream, indicated by a dotted line and identified by numeral 12 will be parallel to the course of stream 11 and always on the diametrically opposite side of the exchanger shell The Operation is e sam f cours whe usi baffles with plates such as shown'in Figures 5 6, 7, 3 and 9.

Various considerations may cause diiferenees in the the rate of flow in the two parallel streams These differences may result from the longitudinal strips 9, from difierences in the relative ararngem ent, oi; the tubes in difierent portions of the cross section of the exchanger, and from the p p on. of feelin material.-

My invention is designed to provide for these. difierences of resistance to flow in the two channels and the provision which has been made is both simple and ade qu e, and i a l m ortan elem t oi invention. My invention provides for the nti ual balancing of these diiferences', ata succession of points throughout the length of the exchanger, by providing a substantialarea of contact 13 between the two streams at, each baffle. Intermixing of the two streams occurs at the. unpartitioned area 13 between the two streams. and at every. similar point through the length of the exchanger, This area of contact simultaneously effects a balancing of the streams and a certain intermixing of the streams that equalizes the temperatures of the'two, This in vention enables me to secure as much as l5 per cent more heat transfer per square foot of tube Surface than is obtained in conventional types of heat exhjangers and consequently permits an important reduction in, the size, tube surface, andcost of heat exchange, equip.-. ment.

The ballle structure herein describedhas particular application to heat exehangers'of the shell and tube type and is adapted to a wide application in the field, inclutl} ing such specific apparatus as condensers, reboilers, etc as Well as that large class of devices known simplyas heat exchangers. In addition, while shell and tube heat, exchangers are frequently limited to use in systems wherein shell fluid and; tube fluid are liquidonly, 110 81 5 1.. restriction in use is contemplated in this apparatus since the disclosed apparatus will functionefficiently whether the heat exchanging media are liquids, gases, or any combination of liquid and gas. The term gas is, here used, of course, to embrace all vapors,

In this specification and in the appended claims I; speak of the various

individual plates

6,71,25,28, 29; 30; and 311 as being in the form of a segment of 'arr ellipse? When I use the expression, a, segment of an ellipse I mean thereby any portion of an ellipse less than a full; ellipse, regardless erwhether the non-elliptic portion. ofits periphery be aradius or the ellipse, a chord. of. the. ellipse, or have some other configuration.

In this specification and in the; appended claims, when,

I use the term plate, I; use it in its ord a ry senseand} mean thereby a flatpiece of material;

What I' claim is:

1. In a cylindric heat exchanger of; the parallel, tube type, a bafilesystem which comprises a plurality of. baffles, each baffle comprising-two plates; cach'platebeing in the form of a segment of an ellipse, the. saidjsegrnent, being a semi-ellipse, including all of the major axisofi said ellipse,

along at least a portion of the length thereof', ea c h plate.

plurality of tubes;withthe minor axes of the twojplates ofeach baffle in longitudinal 'alignment with. the planes.

of the two plates at an angle to each othe i' and; at. an angle to the longitudinal axis of; the cylindric: heat ex changer, and with the extensions of thejtwo p1ates,inter-- locking.

In a y nd i heat. ex hang r. of. the-P ra l l. b yp a fii sy m w ic ampu e a. p u a n of: bafiles, each bafiie comprising. two. PlateS,; each, plate, g n. he o m.v of. segm nt f anelli se, the said m nt e ng air llipsei. xi i; said ll pse and. a xtension. of nifo m Width yond; aid. meter. xis. hreush t ea t garden. il

n an en y n said; mater axis.-

. pe he p a e here hrough. of.

including, all, (iii the... mei tthe length thereot. each pla e e ng. pierc d to re ei e: a plurality of; tubes, the two plates abutting at the inter section of their major and minor axes, with the minor axes of the two plates of each baffle in longitudinal align. ment, with the planes of the two plates at an angle to each other and at an angle to the. longitudinal axis of the cylindric heat exchanger and with. the extensions of the two plates interlocking.v

3. In a cylindric heat; exchanger of the parallel tube type, a bafiie. system which comprises av plurality of bat les, each bafile comprising; twotplates, each plate being in the. form of a segment of. anTellipse out along the. major axis thereof for one-half the length of such axisand carrying an extension therebeyond: along.- the, re: mainder of said major axis, each plate, being pierced to receive, a plurality of tubes; the two plates. of each baffle being positioned at an angle to each other and abutting at t e' intersection of the major and minor axes, with the minor axes of the twoplatesof each baffle. inlongitudinal; alignment, with the minor axes offthe plates. in successive baffles lying in, a.- singlev plane, with the planes. of the two plates at an angle. to. the. longitudinal axis of the cylindric heat, exchanger, with extensions of the two plates interlocking. and with. a, plurality of longi-. ltjiicfinal strips positioned in the. curved periphery of the 4. In a cylindric heat exchanger of, the parallel tube type, a baffle system which comprises aplurality of bafiles, each bafile comprising two plates, each plate being in. the form of a segment of an, ellipse out along the major axis thereof for one-half of the length of said axis and carrying an extension of substantially uniform width along the remainder of saidmaior axis, eachplate being pierced to receive a, plurality of tubes; the two plates of each baifie being positioned at an angle to each other and abuttingv one another at apoint. located substantially.

midway on the major axes of said plates, with the. minor axes of the two plates of each baffle in longitud'inallalignment, with the minor axes of the plates in successive bafil'es lying in a single plane, w-ith the. planes of the. two plates at anangle to the longitudinal, axis of the. cyl'in: dric heat exchanger and with the extensions of the two plates of the bafiie interlocking.

5. In acylindric heat exchanger of the parallel. tube type, a baflle system which comprises aplurality of battles, each baflle comprising two plates, each plate being, in the form of asegmentof an ellipse out along. the major. axis. thereof for one-half the length'of said axis and carrying an extension ofsubstantially uniform width along the remainder of said major axis,each plate being pierced. to receive a plurality of tubes; the two. plates of each b.afile being positioned at an angle to each other and abutting. one another ata point located substantially midway on the major axes of said plates, with the minor axes of thetwo platesofeach bafiie in longitudinal align.- of the plates of successive a singleplane, with" the planes of theangle to each other and at' an angleto,

battles. lying in two plates at an the longitudinal. axis of the cylindric heat exchanger and.

with theextensions of the two terlock.

6,. In a cylindric heat exchanger of the parallel. tube type, a battle system. which comprises a-pl'urality'of baffies, each baffle comprising two plates, each plate being in the form; of asegment ofi'an ellipse, asemi-ellipse,

plates overlapping in in.-

and with its straight side. out parallel to themajor; axis; thereof," with-a notch cut along the; minor. axisfrom the: straightv out side of the segment of the ellipse to: the intersection of the-major; and. minor axes thereof; with, thetwo. plates of a battle positioned at an angle to. each other and abutting at the intersection of their major and minor axes, with their minor. axes: in long tudinal alignment, the. minor axesof'the plates of successive bafiles lying in. asingle plane, with the planes of the plates at an angle. to the: longitudinal axis of the cylindric heat exchanger, each plate being pierced to receive. a. plurality oftubes 7.. In a. cylindric heat exchanger of:

the parallel tubetype, a bafile system which.

comprises aplurality of ballles, each bafllecomprising two plates, each pIatebeing, in theform of} a, segment of: an ellipse, somewhat more than; a semi-ellipse; parallel: tothe major; axis the minor axis th and with. its straightside out thereof, with: a notch cutalong straight; cut. side of. the. segment hei llips rtc h intersection.. of; the major andzmiaor somewhat more than.

axes thereof; with the two plates of a baffle positioned at an angle to each other and abutting at the; intersection of their major and minor axes, with their minor axes in longitudinal alignment, the minor axes of the plates of successive baffies lying in a single plane, with the planes of the plates at an angle to the longitudinal axis of the cylindric heat exchanger, each plate being pierced to receive a plurality of tubes, and a plurality of longitudinal strips positioned about the curved periphery of the balhes.

8. A heat exchange apparatus of the shell and tube type which comprises two circular tube-sheets positioned substantially parallel to one another and apart from one another, each tube-sheet pierced with a plurality of holes adapted to receive tubes; a plurality of tubes extending in parallel from one tube-sheet to the other tube-sheet and fastened thereinto with fluid-tight joints; a header over each tube-sheet and a conduit connection to each header; a cylindric shell extending from one tube-sheet to the other tube-sheet, surrounding the plurality of tubes and made fluid-tight to said tube-sheets; a conduit connection adjacent to each end of the cylindric shell; a plurality of bafiles within the shell extending in series from one end of the shell to the other end thereof, each bafile comprising two plates; each of the two plates of a baffle being in the form of a segment of an ellipse, out along the major axis thereof for one-half the length of such axis and carrying an extension of substantially uniform width along the remainder of the major axis; each plate being pierced to permit the passage therethrough of the said plurality of tubes which extend from one tubesheet to the other tube-sheet; the two plates of each baffle being positioned alongside of each other with their curved peripheries abutting the interior wall of the shell, with the minor axes of the two plates in longitudinal alignment, with the planes of the two plates at an angle to each other and at an angle to the longitudinal axis of the shell, and with the said extensions of the two plates interlocking.

9. A heat exchange appartus of the shell and tube type which comprises two circular tube-sheets positioned substantially parallel to one another and apart from one another, each tube-sheet pierced with a plurality of holes adapted to receive tubes; a plurality of tubes extending in parallel from one tube-sheet to the other tube-sheet and fastened thereinto with fluid-tight joints; a header over each tube-sheet and a conduit connection to each header; a cylindric shell extending from one tube-sheet to the other tube-sheet, surrounding the plurality of tubes and made fluid-tight to said tube-sheets; a conduit connection adjacent to each end of the cylindric shell; a plurality of baffles within the shell extending in series from one end of the shell to the other end thereof, each bafile comprising two plates; each of the two plates of a baffie being in the form of a segment of an ellipse, cut along the major axis thereof for one-half the length of such axis and carrying an extension of substantially uniform width along the remainder of the major axis; each plate being pierced to permit the passage therethrough of the said plurality of tubes which extend from one tube-sheet to the other tube-sheet; the two plates of each baffle being positioned alongside of each other with their curved peripheries abutting the interior wall of the shell, with the minor axes of the two plates in longitudinal alignment, with the planes of the two plates at an angle to each other and at an angle to the longitudinal axis of the shell, and with the said extensions of the two plates interlocking; and longitudinal strips extending from the first bafile in the series to the last bafile in the series and affixed to each baffie to maintain them in spatial relationship with each other, these longitudinal strips being positioned close to the exchanger shell.

10. A heat exchange apparatus of the shell and tube type which comprises two circular tube-sheets positioned substantially parallel to one another and apart from one another, each tube-sheet pierced with a plurality of holes adapted to receive tubes; a plurality of tubes extending in parallel from one tube-sheet to the other tube-sheet and fastened thereinto with fluid-tight joints; a header over each tube-sheet and a conduit connection to each header; a cylindric shell extending from one tube-sheet to the other tube-sheet, surrounding the plurality of tubes and made fluid-tight to said tube-sheets; a conduit connection adjacent to each end of the cylindric shell; a plurality of bafileswithin the shell extending in series from one end of the shell to the other end thereof, each baffle comprising two plates; each of the two plates of a battle being in the form of a segment of an ellipse, cut along the major axis thereof for one-half the length of such axis and carrying an extension of substantially uniform width along the remainder of the major axis; each plate being pierced to permit the passage therethrough or the said plurality of tubes which extend from one tube-sheet to the other tube-sheet; the two plates of each battle being positioned alongside of each other with their curved peripheries abutting the interior wall of the shell, with the minor axes of the two plates in longituciinal alignment, with the planes of the two plates at an angle to each other and at an angle to the longitudinal axis or the shell, and with the said extensions or the two plates interloclu'ng; and longitudinal elements extending Iron-i the h'rst battle in the series to the last bathe in the series and affixed to each battle to maintain them in spatial relationship with each other.

11. A heat exchange apparatus of the shell and tube type which comprises two circular tube-sheets positioned suostantially parallel to one another and apart t'rorn one another, each tube-sheet pierced with a plurality of holes adapted to receive tubes; a plurality or tubes extending in parallel from one tube-sheet to the other tube-sheet and fastened thereinto with fluid-tight joints; a header over each tube-sheet and a conduit connection to each header; a cylindric shell extending from one tube-sheet to the other tube-sheet, surrounding the plurality of tubes and made fluid-tight to said tube-sheets; a conduit connection ad acent to each end of the cylindric shell; a plurality of bafides positioned within the shell between the two ends thereof, each such bal'lle comprising two plates; each of the two plates of a baflle being in the form of a segment of an ellipse out along the major axis thereof for one-half the length of such axis and carrying an extension of substantially uniform width along the remainder of the major axis, each plate being pierced to permit the passage lherethrough of the said plurality of tubes which extend from one tube-sheet to the other tube-sheet; two plates of each bafile being positioned alongside of each other with their curved peripheries abutting the interior wall of the shell, with the minor axes of the two plates in longitudinal alignment, with the planes of the two plates at an angle to each other, each plate of the pair being at approximately the same angle to the longitudinal axis of the shell, and with the said extensions of each plate overlapping the companion plate and interlocking.

12. A heat exchange apparatus of the shell and tube type which comprises two circular tube-sheets positioned substantially parallel to one another and apart from one another, each tube-sheet pierced with a plurality of holes adapted to receive tubes; a plurality of tubes extending in parallel from one tube-sheet to the other tube-sheet and fastened thereinto with fluid-tight joints; a header over each tube-sheet and a conduit connection to each header; a cylindric shell extending from one tube-sheet to the other tube-sheet, surrounding the plurality of tubes and made fluid-tight to said tube-sheets; a conduit connection adjacent to each end of the cylindric shell; a plurality of baffies within the shell extending in series from one end of the shell to the other end thereof, each baflle comprising two plates, each of the two plates of a battle being in the form of a segment of an ellipse, cut along the major axis thereof and carrying two extensions of substantially uniform width along the major axis, each plate being pierced to permit passage therethrough of the said plurality of tubes which extend from one tube-sheet to the other tube-sheet, the two plates of each baflle being positioned adjacent each other with their curved peripheries abutting the interior shell wall with the minor axes of the two plates in longitudinal alignment with the planes of the two plates at an angle to each other and at an angle to the longitudinal axis of the shell, and with the said extensions of the two plates interlocking.

13. A heat exchange apparatus of the shell and tube type which comprises two circular tube-sheets positioned substantially parallel to one another and apart from one another, each tube-sheet pierced with a plurality of holes adapted to receive tubes; a plurality of tubes extending in parallel from one tube-sheet to the other tube-sheet and fastened thereinto with fluid-tight joints; a header over each tube-sheet and a conduit con-- nection to each header; a cylindric shell extending from one tube-sheet to the other tube-sheet, surrounding the plurality of tubes and made fluid-tight to said tube sheets; a conduit connection adjacent to each end of the cylindric shell; a plurality of baflles within the shell extending in series from one end of the shell to the other end thereof, each bafile comprising two plates; each of the two plates of a baflle being in the form of a segment of an ellipse, cut along the major axis thereof for onehalf the length of such axis and carrying an extension of substantially uniform width along the remainder of the major axis; each plate being pierced to permit the passage therethrough of the said plurality of tubes which extend from one tube-sheet to the other tube-sheet; the two plates of each bafiie being positioned alongside of each other with their curved peripheries abutting the interior wall of the shell, with the minor axes of the two plates in longitudinal alignment, with the planes of the two plates at an angle to each other and at an angle to the longitudinal -axis of the shell and with the said extensions of the two plates interlocking.

14. In a cylindric heat exchanger of the parallel tube type, a bafile system which comprises a series of baffles, each baffle comprising two plates, each plate being in the form of a segment of an ellipse and including not less than 180 of the ellipse, measured from the major axis thereof, each plate being pierced to permit the passage therethrough of a plurality of tubes; the two plates of each bafiie being positioned at an angle to each other and abutting at the intersection of their major and minor axes, with the minor axes of the two plates of each baflie in longitudinal alignment, with the minor axes of the plates in successive baflles lying in a single plane, and with the planes of the two plates at an angle to the longitudinal axis of the cylindric heat exchanger; the series of bafiles creating two similar and diametrically adjacent passageways of generally helical shape from the first battle of the series to the last bafide of the series, and the said passageways being in open communication with each other.

15. In a cylindric heat exchanger of the parallel tube type, a baflle system which comprises a series of baffies, each baffle comprising two plates, each plate being in the form of a segment of an ellipse, including a semi-ellipse lying altogether on one side of the major axis, each plate being pierced to permit the passage therethrough of a plurality of tubes; the two plates of each bafile being positioned at an angle to each other and abutting at the intersection of their major and minor axes, with the minor axes of the two plates of each bafile in longitudinal alignment, with the minor axes of the plates in successive baflles lying in a single plane, and with the planes of the two plates at an angle to the longitudinal axis of the cylindric heat exchanger; the series of bafiies creating two similar and diametrically adjacent passageways of generally helical shape from the first baffle of the series to the last bafile of the series, and the said passageways being in open communication with each er.

16. In a cylindric heat exchanger of the parallel tube type, a baffle system which comprises a series of baflles, each baffle comprising two plates, each plate being in the form of a segment of an ellipse and including not less than 180 of the ellipse, measured from the major axis thereof; with the two plates of a battle positioned at an angle to each other and abutting at the intersection of their major and minor axes, with their minor axes in longitudinal alignment, the minor axes of the plates of successive baffies lying in a single plane, with the planes of the plates at an angle to the longitudinal axis of the cylindric heat exchanger, each plate being pierced to to permit the passage therethrough of a plurality of tubes; the series of bafiles creating two similar and diametrically adjacent passageways of generally helical shape from the first baflie of the series to the last baffle of the series, and the said passageways being in open communication with each other.

17. In a cylindric heat exchanger of the multiple tube type, a baflle system which comprises a plurality of baffles, each bafile comprising two similar plates; each plate being in the form of a segment of an ellipse, the said segment comprising a semi-ellipse, including all of the said ellipse lying on one side of the major axis thereof, and at least one extension beyond said major axis, the said extension being bounded by a' radius of the ellipse and the periphery of said ellipse and having an area not exceeding twenty per cent of the area of the full ellipse, a plurality of holes through each plate to permit the passage therethrough of the heat-exchange tube; the two plates of each bafile abutting at the intersection of their major and minor axes, with the minor axes of the two plates of each baffle in longitudinal alignment, with the planes of the two plates at an angle to each other and to the longitudinal axis of the cylindric heat exchanger, and with the minor axes of the plates in successive baflles lying in a single plane.

18. In a cylindric heat exchanger of the multiple tube type, a bafiie system which comprises a plurality of battles, each baffle comprising two similar plates; each plate being in the form of a segment of an ellipse, the said segment comprising a semi-ellipse, including all of the said ellipse lying on one side of the major axis thereof, and at least one extension beyond said major axis, the said extension being bounded by a line extending from the intersection of the major axis with the periphery of the ellipse to a point on the minor axis outside the semi-ellipse, and back along the minor axis to the major axis, and having an area not exceeding twenty per cent of the area of the full ellipse; a plurality of holes through each plate to permit the passage therethrough of the heat-exchange tubes; the two plates of each bafile abutting at the intersection of their major and minor axes, with the minor axes of the two plates of each battle in longitudinal alignment, with the planes of the two plates at an angle to each other and to the longitudinal axis of the cylindric heat exchanger, and with the minor axes of the plates in successive baffles lying in a single plane.

19. In a cylindric heat exchanger of the parallel tube type, a bafile system which comprises a plurality of bafiles, each baflle comprising two plates; each plate being in the form of a segment of an ellipse, the said segment being a semi-ellipse, including all of the major axis of said ellipse, and an extension in the same plane beyond said major axis along at least a portion of the length thereof, each plate being pierced to permit the passage therethrough of a plurality of tubes; with the minor axes of the two plates of each baflle in longitudinal alignment, with the planes of the two plates at an angle to each other and at an angle to the longitudinal axis of the cylindric heat exchanger; the said bafile system defining two similar and diametrically adjacent helical paths, in open communication with one another from the line of the minor axes of the plates of one bafile to the line of the minor axes of the plates of the next bafifle.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,181,704 McNeal Nov. 28, 1939 2,384,714 Villiger Sept. 11, 1945