US2621903A - Heat exchange tubing - Google Patents

Description

Dec. 16, '1952 l. H. coHLER 2,621,903

HEAT EXCHANGE TUBING Filed July 2, 1949 O L um @Y y Patented Dec. 1K6, 1.9542

UNITED-f STA-TES PATENT OFFICE HEATEX-'CHANGE'TUBING Irving H; Cohler, Chicago, Ill. Appiitatibn J1y2; 1949, serial No. 102,791

6 Claims.- 14 My invention Vrelates-to heat-[exchange apparatus -andl is particularlyv concerned with v*heat eX- change tubing, particularly for user in liquid' coolers and heaters,condensers, heating and cooling coils, and heatpexchangers generally;

Various types of heat exchange equipment, and tubing for use or in connection therewith, have heretofore been proposed Yand. gone intol widespread'nse'in theart. By and large, these have ciencyl A'typical-"caseinvolves'watercooling ap- A paratusV where-the possibilityofjcontaininaticn'of v theA 4water-*by leakage-fromthe piping" carrying the refrigeratingor coolingrnediuin -befrel duced-toV aqznractical4 minimum'withoit," h'wever,

undulyy Aiinpairing the heat transfer eniciency or*j thelsystem.- Efforts heret'oformadsatisiactorily to meet this Situatin havrfailed generauy betransferofothersuggested equipment.'

Inlgeneral,my` invention comprises the' production .ofy novel -heatexchange Atubin;g""cor1c'1'p ing :at

least twovindividualmet'alA tubes which maybe Yof the` same lor different f' cross *sectional sie and shapeQlmade: cfa metal of good 'heatco'ndiictivity for example,-copper,-copper alloys,"stainlessA steel, 'n or the like, said tubesbeingof generallyfrundd cross'section, said-tubes being disposedin `parallel longitudinal lrelationship with"A each' 'other'. For most purposes; only twoindividu'al" tubesare utilized and,ly most advantageously, they areV of conventionaltype;namely;-their inneriand'ut'er peripherieslbeingcircularin cross section? For "certain typesf ofnheatfexchange problems;` three" or more individuali metal tubes' may be utilized "and,

in such cases, f all ofi saidl tubes 'fare-disposed longitudinal! or `parallel relationship with Veach other. i Theouter surfaces? ofthe twov tubes, or the outer. surfaces 'ofthe adjacent -tubes *many S50 series of more than two tubesgfarein contact'with eachother over onlyl a portion,- Uparticularly over only a` small fractiomof theirfsurf-aceareas andAv the adjacent tubes `are'united to-each 'other over onlyA a small area'invimmediate juxtarosit-ionL to outer peripheries of which are circular in cross section, the Contact between such tubesgifvthey' are of equal diameter; is theoretically a line contact although, as a practical proposition,l it is greater than that. In any event, the area of cone tact between adjacent tubes is small in relation tothe totality of their external surfaces.v`v

good thermal conductivityas; for example, cop;

per, copper alloys, stainless steel, or the like'.` The banding may take the formof round or flat wiref of relatively rwide indivdualsheets'or preformed tubes, but it is particularly desirablethat it be of iiat strip-material. Thebanding may take Vari ious forms,v asdescribed hereafter in greater deltail rin` conjunction with the drawing, and it" should contact the tubes over a substantial area, preferably from about 50% toV about 75%, of 'their external surfaces.` It serves to provide a high Ydegree of heat transfer surface from one'tube' toanother with a substantially minimum amountof physicalcontact between the "individualtubes'f- The construction issuch as to' leave 01 psitelydis` posed'air spaces den'ed by portions of the outerV periphery of each ofv said tubes and the inner surfaces offsaidbanding;

The invention will be particularly clearlyV under-- stood in the light of the accompanying `'drawing which' illustrates various 'embodiments of my invention'and wherein Fig; l is an elevational View of one embodiment of heat exchangetubing vmade in accorda ance with my invention;

Fig. 2 is an elevational view of a'second embodiment of my invention;

Fig. 3 is an elevational view of a third embodiment of'my invention;

Fig. 4 is an elevational view of a fourth'embodment of my invention;

Fig. 5 is acrosssectional view taken along "the line 5`-5 of Fig; 1;

Figf is af'cross sectional'viewr of another `embodiment of my invention;

, Fig 7 isa cross sectional'view of lstilll another 1 embodiment of my invention;

Fig. 8 shows heatexhange tubing; made-in accordance with my' invention, wound into fa* coil; and

Fig. s s'hows a `stm further modified emmen--A ment utilizing certainv features" of my invention;

disposed in parallel longitudinal relationship to each other and united or bonded together as shown at I2 and I3. The union or bonding may be continuous along the length of the tubes or it may be at spaced intervals. Two lines of bonding may be employed or the bonding may be along only one line. It is most advantageous that the bonding be along two lines, as shown, that it be continuous or substantially so. The bonding may be accomplished by welding, by means of solder or like materials or in any other suitable manner. In any event, it will be noted that the tubes are united to each other over only a very small area immediately adjacent to their areas of contact. A continuous flat metallic strip I4 is wound helically around the tubes to form an encompassing metallic banding, the windings of said banding being slightly spaced from each other to provide apertures or spaces I6. As shown more particularly in Fig. 5, the banding I4 is bonded to the tubes at I'I, I8, I9 and 2|. This bonding need not be at al1 of said areas and, as described in connection with the bonding at I2 and I3, it may be continuous or discontinuous along the width of each winding of said banding. It is particularly desirable that the bonding area encompass substantially the entire surface between the banding and those areas of the tubes with which said banding is in contact. This may be accomplished by welding, soldering or like operations. The construction described provides oppositely disposed separate air spaces 22 and 23 defined by portions of the outer periphery of each of the tubes and the inner surfaces of said banding. Any leakage in either of the tubes I or II would be readily manifested through apertures or spaces I6.

In Fig. 2, the construction is similar to that of Figs. 1 and 5 except that the metallic banding 24 is helically wound in such a manner as to' leave no space between the successive windings, and holes or apertures 26 are provided in said banding in lieu of spaces I6 in the embodiment of Figs. 1 and 5.

Fig. 3 shows a construction wherein individual metallic bands 21, spaced from each other, are utilized to form the encompassing metallic banding, and Fig. 4 shows a construction similar to that of Fig. 3 except that the individual bands 28 are not spaced from each other and are provided with holes or apertures 29.

In Figs. 3 and 4, instead of using a plurality of individual bands, I may employ a single band made from a single, relatively wide sheet of copper, copper alloy or other metal of good heat conductivity. The single sheet of metal may be wrapped around the tubing and suitably bonded thereto to form the encompassing metallic banding, or the banding may comprise a preformed tube which may be slipped over the tubing and suitably bonded thereto, as described above.

Fig. 6 shows an embodiment of my invention wherein three tubes, 3I, 32 and 33, are employed, the adjacent tubes of which are bonded to each other at 34, 36, 31 and 38. The encompassing metallic banding 39 may take any of the illustrative forms shown in Figs. 1 to 5, inclusive, and bonding may be effected at several areas as, for example at 4I, 42, 43 and 44. In the embodiment of Fig. 6, it will be noted that the banding 39 is crimped inwardly adjacent the air spaces, preferably at all four points 45, 46, 41 and 4B. This crimping may be accomplished by any suitable tool or equipment and serves to improve the thermal efficiency of the unit. It

will be understood that, if desired, this crimping feature may be employed in any of the embodiments of Figs. 1 to 5, inclusive.

Fig. '7 shows a construction wherein the tubes 49 and 5I are of generally elliptical configuration and are in contact with each other along a line drawn through their major or transverse axes. Bonding and banding may be similar to that described above.

In Fig. 8, I show the tubular construction of my invention arranged in the form of a coil 52. In this connection, it should be noted that the coil may be made in various ways and by various sequences of steps. The use of such coils is especially advantageous in various heat exchange arrangements and such coils comprise an important, though limited, embodiment of my invention.

In the construction of Fig. 9, it will be noted that each convolution of the coil 53 is not provided with separate banding. Rather, the banding 54 is wound or wrapped around the preformed coil of the two or more individual tubes bonded together as described above, or bonded together at any other suitable stage in the manufacture of the iinished coil, and said encompassing metallic banding is united or bonded to said tubes and preferably crimped as shown a 55.

While my invention has been described in detail, no unnecessary limitations should be read thereinto, the scope of the invention being set out in the appended claims.

What I claim as new and desire to protect by Letters Patent of the United States is:

1. A prefabricated heat exchange tubing structure comprising at least two individual metal tubes of generally rounded cross section, all of said metal tubes being disposed in essentially a single plane and in parallel longitudinal relationship with each other, the outer surfaces of only the adjacent metal tubes being in contact with each other over substantially only a line contact, each of said metal tubes being metallically and rigidly bonded to its adjacent metal tube over only a small area immediately adjacent their lines of contact to provide a rst path of good thermal conductivity between the adjacent metal tubes and to give rigidity tothe heat exl change tubing structure, and metallic banding of good thermal conductivity encompassing said metal tubes, contacting said metal tubes over a substantial area of their external surfaces and being metallically and rigidly bonded to said metal tubes to provide a second path of goodV thermal conductivity between the metal tubes and also to give rigidity to the heat exchange tubing structure, there being oppositely disposed separate air spaces defined by portions of the outer surfaces of each of said metal tubes and the inner surfaces of said metallic banding for collecting liuid from said metal tubes in the event of rupture of any of said metal tubes within the confines of said metallic banding and adjacent the air spaces and for effectively preventing intermingling of the fluids in said metal tubes upon such rupturing of any of said metal tubes, said encompassing metallic banding having apertures communicating with said air spaces so that leakage from said metal tubes into any of said air spaces upon rupture of any of said metal tubes may be readily detected through` amanece 2. A :.prefabricated` .heat l.exchange :tubing1 structure.; comprising.y at least. two .individual metal tubes :of generally rounded cross section, all of said.metaltubes.beingdisposed in essentially a.

singlgplane and in parallelv longitudinal relationship with each other,.the outer surfacesof only; the adjacentmetalv tubes being in contact withfeachr other over substantiallyy only a line contact, each ofsaid metal tubes beingmetalli.- cally. andrigidly bonded to rits .adjacent metal tube over only a small area immediately adjacenttheir lines ofcontact to providea flrst path of good thermal conductivity between the adja-v centmetalltubes and to give rigidityto the heatI exchangev tubing.. structure, and metallic banding oflgoodthermal conductivity encompassing said metal' tubes, being partially crimped `about vsaid metal tubes andcontacting said metal tubes over a substantialV area of their external surfaces and being metallically andf rigidlyV bonded to said metal tubes to provide a second path of good thermal conductivity between the metaltubes,

and also to give rigidity to the heat" exchange tubing structure, therefbeingoppositely disposed separate air spaces dened by; portions of the outerjsurfacesof each of said metal tubes and thefinner surfaces of the crimpedportions of said metallic4 banding for collectingfluid from: said.

3. A prefabricated heat exchange tubing struc-- ture comprising at least two individual metal tubes of generally rounded cross section, all of said metal tubes being disposed in essentially a single plane and in parallel longitudinal relationship with each other, the outer surfaces of only the adjacent metal tubes being in contact with each other over substantially only a line contact, each of said metal tubes being metallically and rigidly bonded to its adjacent metal tube over only a small area immediately adjacent their lines of contact to provide a first path of good thermal conductivity between the adjacent metal tubes and to give rigidity to the heat exchange tubing structure, and metallic banding of good thermal conductivity encompassing said metal tubes, contacting said metal tubes over a substantial area of their external surfaces and being metallically and rigidly bonded to said metal tubes to provide a second path of good thermal conductivity between the metal tubes and also to give rigidity to the heat exchange tubing structure, there being oppositely disposed separate air spaces defined by portions of the outer surfaces of each of said metal tubes and the inner surfaces of said metallic banding for collecting fluid from said metal tubes in the event of rupture of any of said metal tubes within the confines of said metallic banding and adjacent the air spaces and for effectively preventing intermingling of the uids in said metal tubes upon such rupturing of any of said metal tubes, said encompassing metallic banding consisting of a relatively nat and narrow metallic band helically wound aroundrsaid` tubes. withzthe-windingzonsaid, metallic band being' slightly;` spaced fromv each#- other to provide apertures-communicatingwith; said air spaces so that leakage from said-metal tubes into any of said air spaces upon .rupture of any of said metal tubes-may bereadily; de-

tected through said apertures from theexterior: of the prefabricated heat exchange tubing;struc.

ture..

4. A prefabricated heat exchange tubing strucf ture comprising at least two. individual metal,

tubes of generallyrounded cross section, all of said metal tubes being disposed in essentially a single plane and in parallel longitudinal relationship with each other, the outer surfaces ofonlythe adjacent metalV tubes being in contactiwith each.V

other over substantially only a line contact,.each of said metal tubes being *metallically and rigide lyfbonded to its adjacent metal tubeloverfonlyfa small areaimmediately adjacent'their lineswoi-l contact to provide a first path of good thermal conductivity between the adjacent. metal-tubes and to give rigidity to the heat exchange tubing; structure, yanclmetallic bandingof good thermal: conductivity encompassing said metal tubes, lcon.-` tacting said metal tubes overa substantial area'` of theirr external surfaces and being metallically andnrigidly bonded to'said metal tubes toprovide' a second path of good thermal conductivity-,be` tween the metal tubes and also togive rigidity;

to theheat exchange tubing structure,;there beA ing oppositely disposed separate air spacesdefined byportions-of the outer surfaces of eachv of-said metal tubes and the inner surfaces of vsaid metallic banding for collecting fluid from said metal tubes in the event of rupture of any of said metal tubes within the confines of said metallic band ing andadjacent the air spaces and for effectivelyr preventing intermingling of the fluids. in said metal tubes upon such rupturingV of any of' said-r metaltubes, said encompassingmetallic banding:v

consisting of aerelatively flat and nar-rowfmetallic band helicallyvwound aroundy said tubes and'having holes spaced therealong to provide apertures communicating with said air spaces so that leakage from said metal tubes into any of said air spaces upon rupture of any of said metal tubes may be readily detected through said apertures from the exterior of the prefabricated heat exchange tubing structure.

5. A prefabricated heat exchange tubing structure comprising at least two individual metal tubes of generally rounded cross section, all of said metal tubes being disposed in essentially a single plane and in parallel longitudinal relationship with each other, the outer surfaces of only the adjacent metal tubes being in contact with each other over substantially only a line contact, each of said metal tubes being metallically and rigidly bonded to its adjacent metal tube over only a small area immediately adjacent their lines of contact to provide a first path of good thermal conductivity between the adjacent metal tubes and to give rigidity to the heat exchange tubing structure, and metallic banding of good thermal conductivity encompassing said metal tubes, contacting said metal tubes over a substantial area of their external surfaces and being metallically and rigidly bonded to said metal tubes to provide a second path of good thermal conductivity between the metal tubes and also to give rigidity to the heat exchange tubing structure, there being oppositely disposed separate air spaces defined by portions of the outer surfaces of each of said metal tubes and the inner surfaces acentos 'l of 'said metallic banding for collecting fluid from said metal tubes in the event of rupture of any of said metal tubes Within the connes of said metallic banding and adjacent the air spaces and for effectively preventing intermingling of the fluids in said metal tubes upon such ruptur ing of any of said metal tubes, said encompassing metallic banding consisting of a series of individual relatively nat and narrow metallic bands encompassing said metal tubes and spaced slightly from each other to provide apertures communicating With said air spaces so that leakage from said metal tubes into any of said air spaces upon rupture of any of said metal tubes may be readily detected through said apertures from the exterior of the prefabrcated heat exchange tubing structure. Y

6. A prefabricated heat exchange tubing structure' comprising at least tw-o individual metal tubes of generally rounded cross section, all of said metal tubes being disposed in essentially a single plane and in parallel longitudinal relation- :ship with each other, the outer surfaces of only the adjacent metal tubes being in contact with veach other over substantially only a line contact, each of said metal tubes being metallically and rigidly bonded to its adjacent metal tube over only a small area immediately adjacent their lines of contact to provide a rst path of good thermal conductivity between the adjacent metal tubes and to give rigidity to the heat exchange tubing structure, and metallic banding of good thermal conductivity encompassing said metal tubes, contacting said metal tubes over a substantial area of their external surfaces and beo ing metallically and rigidly bonded to said metal tubes to provide a second path of good thermal conductivity between the metal tubes and also to give rigidity to the heat exchange tubing structure, there being oppositely disposed separate air spaces defined by portions of the outer surfaces of each of said metal tubes and the inner surfaces of said metallic banding for collecting fluid from said'metal tubes in the event ofiupture of any of said metal tubes within the confines of said metallic banding and adjacent the air spaces and for effectively preventing intermingling of the uids in said metal tubes upon such rupturing of any of said metal tubes, said encompassing metallic banding consisting of' a series of individual relatively flat and narrow metallic bands encompassing said metal tubes, each said metallic band being provided with holes spaced therealong to provide apertures communicating with said air spaces so that leakage from said metal tubes into any of said air spaces upon rupture of any of said metal tubes may be readily detected through said apertures from the exterior of the prefabricated heat exchangel tubing structure.

IRVING H. COHLER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,799,706 Jacobus Oct. 28, 1930 n 2,032,413 Hall Mar. 3, 1936 2,297,146 Guirl Sept. 29, 1942 2,297,165 Ringel Sept. 29, 1942 2,443,295 Bisch June 15, 1948 FOREIGN PATENTS Number Country Date 18,212 Great Britain Aug. 12, 1912 275,028 Great Britain Aug. 4, 1927 152,795 Germany June 25, 1904 236,648 Switzerland July 2, 1945 OTHER REFERENCES Publication; Fedders News, published by Fedders Radiator Co., Buffalo, New York, February 1940.

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