US2980404A

US2980404A - Heat exchange device

Info

Publication number: US2980404A
Application number: US695154A
Authority: US
Inventors: Carl P Andersen; John C Richardson; Vincent E First
Original assignee: Union Carbide Corp
Current assignee: Union Carbide Corp
Priority date: 1957-11-07
Filing date: 1957-11-07
Publication date: 1961-04-18
Anticipated expiration: 1978-04-18

Description

Apnl 18, 1961 c. P. ANDERSEN ETAL 2,939,404

HEAT EXCHANGE DEVICE Filed Nov. 7, 1957 6 I58 INVENTORS X53 CARL P. ANDERSEN JOHN C. RICHARDSON VINCENT E. FIRST WZ/wi m ATTORNE United States Patent '0 HEAT EXCHANGE DEVICE Carl P. Andersen, Kenmore, N.Y., John C. Richardson, Speedway, Ind., and Vincent E. First, Tonawanda, N.Y., assignors to Union Carbide Corporation, a corporation of New York Filed Nov. 7, 1957, Ser. No. 695,154

8 Claims. (Cl. 257-248) This invention relates to heat exchange devices, and

more particularly to a shell-coil type heat exchanger in which the coils are wound in substantially uniformly spaced concentric layers within the shell.

One disadvantage of the heretofore known shell-coil type heat exchangers is the difiiculty and expense of assembly; that is, economically forming a large number of closely spaced concentric coils into a compact, well integrated bundle which can be handled and placed in a shell without danger of damage or falling apart. The problem is magnified if the heat exchangers are embeddedcoil regenerators for cooling compressed air prior to separation into air components by low-temperature rectification. The coils are embedded in the regenerator packing to provide a means of recovering the refrigeration of an air component as a product gas without contaminating such product with air impurities such as moisture and carbon dioxide. The complexity of the coil assembly problem is illustrated by embedded coil regenerators designed for an air separation plant in which high-purity oxygen product gas is passed through such coils. Such construction may require several miles of tubing wound in perhaps 25 concentric layers. Conceivably the number of separate passages for oxygen flow may exceed 100 tubes, all manifolded together at both ends. 1

Additional requirements for embedded coil regenerators include low pressure drop through the coilstominimize power costs, and low longitudinal heatleak between the ends of the coils. The latter'is necessary because the regenerators must be operated with 'a large temperature difference between the warm end and the cold end, and longitudinal heatleak represents aloss of refrigeration and results in added power costs; Consequently, the number and size of the longitudinal support members for the concentric coil bundle should be minimized.= Still. another requirement of. regenerator coil bundles is that the individual coils be uniformly spaced from each otherso that the fluid passing through the coils is substantially equally warmed by heat transfer from the. regenerator packing through the coil ,walls. Thecoils should also be closely positioned to each other so as to minimize radial temperature gradients in the packing. v s s s A further unique characteristic of embedded coilregenerators is that all of the coils should preferably containabout the same length of tubingv soas toequalize the pressure drop and to obtain uniform flow distribution through the coils. Since the diameters of the coil layers means must be provided for controlling the tube length and coil pitch during winding as well as maintaining the desired pitch of the variouscoil layers after they-are formed. In'the case of large bundles, where the diameter --of the inner and outer layers varies considerably, the "difference in curvature of the layers may also have. a prohbunced efiect on pressure drop. This maynecessitate a slight-variation'in tube length betweentheminnerzand 2,980,404 Patented Apr. 18,

ice

outer coils so as to equalize flow. In such instances, means must be provided which conveniently permit the selection and installation of the optimum length of tubing in each coil.

One object of the present invention is to provide a highly efiicient embedded coil regenerator which is relatively easy and economical to assemble.

Another object of the present invention is to provide an economical method of assembling a bundle of coils in substantially uniformly spaced concentric layers.

A further object is to provide a support system for a bundle of coils in concentric layers whereby the support members regulate the coil pitch during the winding operation, and also maintain the desired pitchof the various coil layers after they formed. f I 7, I

A still further object of the invention is toprovide a support system for a bundle of coils in concentric layers in which the longitudinal heat leak is minimized.

These and other objects and advantages of this invention will be apparent from the following description and accompanying drawings. a

In one embodiment of the present invention, a shellcoil type heat exchanger is provided with concentric layers of coils positioned by coil support means comprising a series of support members extending longitudinally between the coil layers for maintaining the coil layers in suitably spaced relation. Slots are provided in each memberfor receiving and supporting the individual windings of a given layer. A projection between each pair of adjacentslots extends beyond the given layer and provides means for mounting a support member for thenext larger diameter coil layer Also, means such as rivets are provided for securing the next larger diameter coil support member to the projections. The support members for the next larger diameter coil layer may close the slots of the support members of the given coil layer, thereby firmly retaining the coils within the slots. 7 The individual coil support means are preferably angleshaped, with two such angles placed back-to-back as a support member for a given coil layer. It is furthermore desirable to form the base of the slots into saddleswhich receive and distribute the bearing load of the individual coil windings. 7 Y

.In the preferredembodiment, adjacent concentric coil layers are: helically wound in opposite directions, i.e.", one layer iswound clockwise and the next counterclockwise. Such an arrangement improves flow distribution outside of. the coils, and permits equalizing of the stresses inthe coil bundle by interlocking the adjacent coil layers. The present invention also provides a methodfofassembling a coil bundle in substantially uniformly spaced concentric layers in which at least three suppo rt members are first longitudinally secured to and along the length of a central dummy core, the membersbeing situated at substantially uniform intervals around the circumference of of the support members; Next, additional 'coil support members are attached to the members secured to the dummy cute so that the additional members are positioned adjacent to the, outer side of the first coil layer and hold the coil windings in the aforementioned slots. Additional tubes are then wound around the dummy core withtheir coil windings fitting into the slots 'of the additional coil supportmembers to form a larger diameter second cell layer; Additional, still larger diameter coil layers may be V moundaround the dummy l oiclip assembly."

to assemble. a coil bundle of the desired size. Adjacent directions forz he previouslymentionedreasons. fin-th accompanying dra i s: I

mentio fig.) isian as illustrated in i 1; e

end view of the same coil supportfmember fi 3 is an enlarged isometric'view or a pub which is assembled in :pairs for interlocking thecoils of; adjacent layerstogether; r

' jEig; 4 is; a perspective view looking downwardly on an; assembly of coil supports similar to Figsi 1 j and 2 exr icept that the slot saddlesareformed-in the opposite direcinsane? core in .tbesame manner so as;

' coil layers are preferably helically wound in opposite 7 iionjrom the base side of the angle-shaped support members; and Fig.5 is-a perspective view iof'one'side of ,a bundle of {concentricallywound coils embodying one form of the V p tinvent n e I ;Referri ng more speoifically -to.Figs. land 2, the coil 7 The support member 110 includes base leg ll and'verfica lileg 1 2 containing slots 13 at uniformilongitudinal V 4' construction, two back-to-back projections 15a are provided, and the two vertical legs 12b of the support member 10b are rigidlyattachedfto projections a on either side of such projections by means of rivets 18 extending through holes in the verticallegs 12b and the projections 15a. Holes 16d and projections 1' 5aare preferably situated so that the. projections. do not protrude substantially into the hole. area and -thereby're'du'ce the effectiveness of such holes. {Alth'oughiriveting hasbeen described as the means .of connecting adjacent coil supporfmembers, other methods such as spot welding'could be substituted.

In Fig; 4 the saddles 14b arefformed inwardly and in the opposite direction from the base leg 11b; whereas Fig. 2 the saddles are formed outwardly and in the same direction as the base :legf Although'both embodiments perform the desired function of distributing the bearing load on the coils; the Fig.2 'form is preferred. This is because the Fig; 4 saddles .must'be' relativelynarrow; otherwise,

i the angles when placed back-tosback will bespaced too support member 10 isvprejerably angle shaped, and may intervals to receive and support theindividual coil windgi ngs pfqa given layeru 'lheijslots 13 are preferably con 1oured;at the ;bottom to correspond to the shape of the .poil windings; and a portionof th'e metal from the' base .orf the} slots 13 is formed outwardly into a saddle 14 which distributes the bearing load along the tube and '1 7 avoids; excessive abrasion or scoring' on the contact sur- 7 .face. Projections 15 between each pairof-adjacentslots 13 aresuflicientlylongto protrude through the coil layer '-be1ng supported, and provide a means for mounting an ident cal support member lfl'for the next larger diameter c911 layer. {Holes ldstamped in the vertical leg '12 of the snpportrmember '10 and-between the'saddle's .14 serve 9 the longitudinal .heatleak along the supp'ort member 10, Holes 16 also permit lateralflow ofthe'heat exchanging fluid outside ofthe coils,:and help toprevent yoids in a the; packing of the embedded-coil 'r'egenerator embodiment of theinvention." Theilegs Hand 12 or the support member'10 are preferably. bent sof-that 'the verti9a .eg: 12.wi11; xte a approximately :radia'llywhen the .baseylegj L1 mounted 1O ithe curyedfsurface of the dummycore-or-theznext smaller diameter coil assembly as 'described inmorerdetailibelow: e

1 N support; angles 10 are" preferably used pairs at V eachsupport point:for'improved'rigidity. fIn thisjca'sethe a angles aremounted'with their vertical leg's 12'placed backiQ-bQCk-Y "'7 1 7 1 f e ;F ig. 3 illustrates a: clip membei'TIGZz' fwhich is' a rec-,

' 'tangula'r stampingqwith grooves or contours 16b pressed fin either end'ito fitlarouhdsthjcoil surfaces of adjacent .clip 14 5a for passage'therethroughof means fOrsecuring "I1F g- 4 illustrates: a coil :supportfassembly' using the 3: double angle: backetoeback'con lrl ction. {This assembly includes support" member 1011 for receiving the individual I 'coil'windings of-a first coil layer and support member 10b receiyesrthe'jcoilxwindin'gs of a second larger-"diameter coil: layenllIrii thelinterestpf simplicity;zoirly .asinall number ofcoils E'arei fshc vvn bUt it is;to be understood that 7 in; actual practice;acoils may beiheld iu any or'all iofthe slots. L'Ihe coils or :tuhes 5 174 of :the first .coil layer arje iit'nilygheld .lwithin theslotsibythei-basefleg i lboffthe supportmernber: 10b which a'gain'st cbilsi 176.. The. 1 projections 15:: "of the support members ilda are i1fi-.

' ciently rang to protrude beyond coils 174:6: the fi st Myer; A "and provide means for mountingzsupportlnrembersiiflb i a of the second on 1 yer -1-'ib; "n3yuse;

out invention which utilizes the previously described com-- 'ponents.- f A'built-up method of assembling the coil bundle far' apart and the riveted attachment may not be secure. When the saddlesar'e formed in'the same directionas the base'leg there is no limit imposed .on the saddle width'and the. bearing load may be more efiiciently distributed along the coil lengths. I r. v '21: q 1

V Adjacent coils 17a and '17bof the first and second coil layers respectivelyfa're also secured by'a pair of clip members 16a, shown in detail in Fig.1-3,5 which are contoured on either end to fit around the coils. The clip member asembly is heldtogether by bolt and nut assembly 184, the former passing throughclip holes 16c.- The clips perform two functions by equalizing' the torsional forces between the adjacent coil layers andlending torsional frigidity to the entire tube bundle. Concerning the last mentioned function, it was found that a bundle constructed without clipswas'incapable of transmitting the 'winding torque" from thedummy core. to the periphery of the bundle. After reaching a certain diameter; the assembly became so unstable that continued rotation, opposed by the tangentialforce of the tubes being wound "on the bundle, caused thebundle to collapse and fall apart Fig. '5 illustrates a tube bundle according'to the presis employed in which: the coils are;wound layer upon layer usingfithe coil'suppor't: members as jigs during the Winding. operation. 'Iheassembly of acoil bundle is begun by lh orinontally mounting a1 central dummy core ]19 between power'driyen fixtures V20at each end so that v "the.dummy;1co re maybe rotated about its longitudinal {axis "This dummybecomesa permanent core member for-the; coil assemblymnd may, for example,- be a tube slightly longer than theoverall length of the coil bundle. fThe verticallegs of inner supportmembers lo extend radially from the surface of thedurnmy core 1 9 and are jslottediat closeintervalsto receiyeand support the coil windings, as previously described. ,The dummy core is coil' bundles. A holeis provided in the center or the 'fthen rotated and thejtube is fedonto the dummy core assembly. By rotation'ofrthe dummy, the-tubeisformed 60. into: a coil whose vvindings fall'ainto the slots provided in the..inner.coil,support members 10. ,Wooden slats nlay I'he'attached longitudinally to thedummy core 19 or he'dub ns e mam-t between the adjacentTinner. support memberslll so that each can; winding will be formed in a true circle. These i wpodenlslatsiare temporafl and.areremoved'after each coil laYQl lS' completed,- Whenthe first layer is formed, four, additional coil support members "10 are attached .to' projections extending through the completed first coil layer. 17a, :and uare positioned directly-over the inner 'support mem ers 10; 'second setiof support member" hold the second cgiljlay er 17b which is wound ai manner similar toi the firstlayer 17a. The see- {me support members 1 l0 s regat "the I first "coil layer l-flai -and' hold these windingssecurely' in the slots. 13. j

lar ger diainetergcoillayers may. wound the coil bundle.

ternative coil support system comprising bulky beam members would distort the gas fiow' through the packed bed. V

around the dummy core 19 so as to'assemble a coil bundle of the desired size. 7

From the foregoing description, it is seen that the coil support members are stacked one above the other along four radii which extend outwardly from the center of the bundle. When several layers have been wound in this manner, the diameter of the coil layers will have increased so that four support points around their circumferences may not be adequate to position the individual coil windings securely and in parallel relation with each other. When the assembly reaches this stage, four additional coil support members may be attached to the last completed coil layer and are preferably located approximately mid-way between the original support points. When new support points are established, the innermost support member of such new locations will not have the benefit of a rigid dummy core for anchorage as in the case of the first layer of the bundle. The number of support points which must be provided for the outermost coil layers of the completed coil bundle assembly of course depends on the diameter of such bundle. Clips 16a are preferably secured to adjacent coil layers in the previously described manner. If desiredythe core 19 may be removed on completion of the coil assembly. 7 v vA s previously discussed, all-of the coils of embedded coil regenerators preferably have the same pressure drop, and the support system of the present invention facilitates attainment of this objective by performing the double function of controlling the tube length and the coil pitch during the winding operation, and of maintaining the desired pitch once the coil layers are formed. In the innermost layer of the smallest diameter, only one coil is preferably provided with the individual laps falling into adjacent slots on the angle support member. When sufiicient coils have been wound so that a layer is reached in which the circumference has doubled, two coils each equal in length to the innermost coil are provided for the coil layer with their individual windings falling into alternate slots on the coil support member. However, the circumferences of all coil layers are not necessarily integral multiples of the circumference of the innermost layer. In order to keep the tube length and/ or pressure drop of such intermediate circumference layers uniform, it is necessary that one or more of the support slots be skipped in winding each coil of the layer, thereby omitting one or more of the coil turns.

Another feature of the present invention is the winding of adjacent coil layers in opposite directions, i.e., one layer is wound clockwise and the next counterclockwise. One reason for this innovation is that the stresses in the coil bundle may be equalized by interlocking the coil layers, which in turn permits a lighter and simpler support system with less longitudinal heat leak. Adjacent coil layers may be lockedtogether by conventional means, for example, the rigid clips 16a. When adjacent coils are oppositely wound, the coils pull in opposite directions and when locked together, the forces tending to unwind one coil are opposed by similar but opposite forces in the other coil. If the unwinding forces were not opposed but instead placed in the same direction, the lightweight, stacked coil support members would be severely stressed as the entire coil bundle tends to loosen and expand. To avoid this undesirable situation, heavy beam members would be necessary to transfer the torsional loads back to the center dummy core. Such beam members would increase the weight, cost, and complexity of the coil bundle, as well as add to the longitudinal heat transfer through the bundle. Another advantage of the opposite winding technique is improved flow distribution of the cooling air passing through the shell and around This is because the aforementioned al- "From the foregoing description, it may be" seen that the present invention provides an economical method of assembling a bundle of coils in substantially uniformly spaced concentric layers, and additionally provides a highly efiicient embedded coil regenerator. It is to be noted, however, that the present invention is not limited to regenerator-type construction,. but may be applied .to any shell-coil type heat exchanger. Also, the terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of ex-. eluding any equivalents of the features described, It

' should be recognized that various modifications are possible without departing from the scope of the-invention;

What is claimed is: l

l. Coil supporting means for a shell-coil type heat exchanger in which the coils are wound in substantially uniformly and normally spaced concentric layersof re spectively different sizes within the shell, comprising a series of elongated support members extending continuously longitudinally between. the respective adjacent different size coil layers with the widths of ,said continuous members disposed substantially normally tosaid coils for maintaining the coil layers in suitably spaced relation with substantially uniformly longitudinally spaced outwardly opening slots in the outer portion of each support member for receiving and supporting the individual coil windings of a given layer, a substantially flat integral projection between each pair of adjacent slots extending outwardly substantially normal to and beyond the given layer and providing means for mountings, support member for the next larger diameter coil layer with said projection in flat overlapping relation with the lower portion of the'support member to be mounted,

and means for securing the lower portion of the next larger diameter coil supportmernber to said projections in said flat" overlapping relation therewith. p g

2. Coil support means according to claim' 1, in which a portion of the material above the base at the bottom of said slots is formed into a saddle which receives and distributes the bearing load of said individual coil windings of an outer layer of coils.

3. Coil support means according to claim 1, in which each support member comprises two angles placed backto-back with said slots formed in their vertical legs and registering in outwardly opening relation.

4. Coil support means according to claim 1, in which each coil layer is supported by two angles placed backto-back as said support members, and a portion of the bases of said slots of each of the back-to-back angles is formed into a saddle extending in the same direction as the base side of the angles, said saddle receiving and distributing the bearing load of said individual coil windings.

5. Coil supporting means for a shell-coil type heat exchanger in which the coils are wound in substantially uniformly spaced concentric layers within the shell; comprising at least three pairs of angle-shaped members 1 for each coil layer extending longitudinally between the coil layers, each member of the pairs being placed back-to-b'ack and maintaining the coil layers in suitably spacedrelation, with slots in each support member for receiving and supporting the individual coil windings 'of agiven layer, a portion of the bases of said slots being shaped into saddles for receiving and distributing the bearing load of said individual coil windings; a projection between each pair of adjacent slots extending beyond the given layer and providing means for mounting the support members for the next larger diameter coil layer; and means for securing the next larger diameter coil support members to said projections.

6. Coil supporting'means for a shell-coil type heat exchanger in which the coils are wound in substantially uniformly spaced concentric layers within the shell; comprising at least three pairs of angle-shaped members for '7 ber's to said projections.

eg eh mil layer extending longitudinally"betweenfthe a il'layqrwwh memb of e pa s nf'g 'pla edm to backandmaintaining the coil layers suitably'spaced telaiion with slots in 'each' support member f'orreceiv- I m and supporting the individual coil windings of: a givemlayehand the'support members for the ne'xt larger diagneter coil layer closing jsaid slots of the support inenib'ers of said giyen. coil'layer thereby firmly :holding' saidfco ils 'within said slots; ;a ppr'ojection between each of adj'acent slots extending b eyond the given layer eiehanger in fvt'hich the coils are wound in longitudinally spaced, relation in radially spaced concentric layers, with the shell, comprising a series of elongated S1l.pPf0rt extending longitudinally in the'radial space between "said layers with the yvidths of :s'aid n' ernbers e tendij'g' radiallyj for maintaining 'said lay'ersin, radially paced relation withiradially outwardlyopening slotsjin the radially outer portion of eachisupport member or receivingand supporting the individualcoil windings of and providing naeanslfor mounting said' support xnemhersffgr'said next lar ge fdianieter 'coillayer; andfnieans fo 'se'curingsaid next larger diameter coilsupport mem- 7. Coiljsupporting means for shell-coil type heat exchanger in Whichthe coils are wound in substantially uniiornjly and .noimanyapaced concentric; layers within bettileenifthe respective :coil layers with the widthsiof 'said epntinuous me said coilslfofniaintaining thecoil layers in'sui t'ablyr spaced J reliationj saidsupport members *being angle Qshap ed m cross jsectiominga plane transverse to the axis ofjsa'idr coilsiwith base legs engaging the outer; surfaces of an layer'rof 'coilsfand Vertical legs extending outward- 7 f lygfrorn'said base legswith outwardl'y opening slots: in-

the outer portion of said vertical legs for receiving, and

s'iib'stantially wfiat integral projection namengwa pair agingiexg d ng umra1y substantially normal'to and beyond siadr'oute'rQIayerand overlapping-the 'support l fsilpporting' theindividua'l windings of an outer layer", a a

: "2,160,689 YahVulpen member" thereabo'ye alsydna' the base legith'ereof, and

thereaboye to'fs'aid projctions with said pro; 7; :iecti'ons in flat 'overlappingjrelation therewith." i 7 8,:Coi1 supporting neans'for a'shell-coil type heat,

7 means ib: securing, the" lower portion of said support a giyeri layer' a substantially flatrinte'g'ral projectionbetween each: pair oflslots extending radially outward beyond said given layenand overlapping the'next outer support member, and means for securing said overlapping extensions to said next outer support member, each supportrne'mber having holes space'dradially inward from said 'projections and staggered with. respectto the bot- ,toms' of "said :slots "to minimizeglongitudinal heat leak through thegneat'exchanger. ii 1 1' V References Cited the fileo f thisfpatent. ,Bn-sr TEsPAT NT 5 5 Rover EJlll-Y- 11924 1,633,975 f QBroidO June 28, 1927 1,799,O8ll V 'Blomqvisii Mar. 31 1931 l.821;754J Huvetter .,"1Sept. 1,4931 1 ,840,940. 'Ecabert clan. 12, 1932 "1,915,352 Bottoms June 27,1933

, May 30, 1939 2;,2s7goss Rogers June 23, 1942 2371,10? V Mapes Mai-. 16, 1945 2,373,038 Lindsay Apr. 3(19745