US 3670811 A
The essential concept of this invention involves a planar strip of flexible material of predetermined length and width having a series of slits formed therein to define small portions of the strip subject to being bent transversely to the plane of the strip to form tabs when the strip is converted into a sleeve for embracive positioning around groups of fins on a fluid-flow tube with the tabs disposed between fins to secure the sleeve against shifting axially of the tube.
Description (OCR text may contain errors)
United States Patent Christensen [4 1 June 20, 1972  PROTECTION-SLEEVE FOR FINNED- TUBES OF HEAT-EXCHANGER CORE- UNIT  Inventor: Donald W. Christensen, Racine, Wis.
 Assignee: Young Radiator Company, Racine, Wis.
 Filed: April 13,1970
 Appl.No.: 27,906
 U.S.Cl... ..l65/134, 165/178  Int. Cl ..F281'9/00  Fieldofsearch ..165/l34, 67,158-160,
 References Cited UNITED STATES PATENTS 2,610,832 9/1952 Holmes et a1 ..165/l72 2,168,549 8/1939 Young ..l6S/l34 X 3,273,638 9/1966 Darling. 165/ l 34 2,402,209 6/1946 Ryder 165/ l 78 Primary Examiner-Frederick L. Matteson Assistant Examiner-'Iheophil W. Streule Attomey-Edwin Phelps 5?] ABSTRACT The essential concept of this invention involves a planar strip of flexible material of predetermined length and width having a series of slits formed therein to define small portions of the strip subject to being bent transversely to the plane of the strip to form tabs when the strip is converted into a sleeve for embracive positioning around groups of fins on a fluid-flow tube with the tabs disposed between fins to secure the sleeve against shifting axially of the tube.
2 China, 6 Drawing Figures PATENTEnMzo m2 8,670,811 sum 10F 2 in ii H H H H INVENTOR: DONALD W CHRISTENSEN BY v PATENTEDJUH 20 1912 W 1% WW; H Him I W sum 2 OF 2 FIG.5
INVENTOR. DONALD W CHRISTENSEN ATT'Y PROTECTION-SLEEVE FOR FINNED-TUBES OF HEAT- EXCHANGER CORE-UNIT In the current heat-exchanger industry, core-units of extensive sizes have to be produced for effecting temperature changes in fluids flowing through these core-units. At times these core-units may be from ten to twenty or more feet in axial length. Various facilities have had to be developed to counteract possible sagging of such dimensioned core-units.
Prior US. Pat. Nos. disclosing structures for such purpose include 3,420,296; 3,273,638; 2,775,433; 2,402,209; and 1,704,097. Each and every of these disclosures inheres limitations because of problems in production and/or in use.
The main objects of this invention are; to provide an improved forrn of a planar strip of comparatively thin, narrow flexible material for formation into a simple sleeve for embracive location externally around the finned tubes; to provide a planar strip of this kind having-narrow portions thereof preformed to be disposed transversely to the plane of the strip formed sleeve for embracive position around groups of fins and secured against shifting axially of the tube; and to provide a pre-formed strip of this kind of such simple structure as to make highly economical the manufacturing and marketing thereof and exceedingly gratifying and profitable the use thereof by purchasers.
In the adaptation shown in the accompanying drawings;
FIG. 1 is a plan view of a relatively large heat-exchanger, for use with which these pre-forrned planar strips have been designed;
FIG. 2 is a side view of what is shown in FIG. 1;
FIG. 3 is an enlarged, plan view of a pre-formed, planar strip a number of which are shown in position in FIG. 1;
FIG. 4 is a perspective view of a sleeve formed from a strip such as shown in FIG. 3;
FIG. 5 is an enlarged, cross-sectional view of a group of tubes taken on the plane of the line 5-5 of FIG. 1, showing the positioned sleeves; and
FIG. 6 is a much-enlarged, side view of a positioned sleeve taken on the plane of the line 6-6 of FIG. 1.
Heretofore, core-units of these dimensions, on occasion, have been faulted because of the tendency to sag radially. Often this causes the fins on adjacent tubes becoming intermeshed. The result is a lowering of the heat-transfer with a consequent increase in air-pressure demanding a greater horse-power for the motor driving the fan.
A protection sleeve for use with finned heat-exchanger tubes, embodying the foregoing concept, comprises a strip of comparatively thin, flexible material 10 of pre-determined dimension formed with a series of slits 11. The strip 10 is adapted to be converted into a sleeve 12 for embracive positioning around the peripheries of a group of fins mounted on the respective tube 15 with the portions of the strips 10, between the slits 11 disposed radially of the sleeve 12 to form tabs 14 extending axially of the sleeve 12.
Large core-units, such as shown in FIGS. 1 and 2, for use with which these pre-formed strips 10 of flexible material were designed for use, require a very special procedure for assembling. This begins with having the fin material 13 spiralled around, along and bonded to each tube 15 (FIG. 6). This being effected, several strips of the flexible material 10, with the tabs 14 turned inwardly, are set around the groups of fins 13 along each tube 15. The ends of each such strip 10 are overlapped and bonded together to form a sleeve (FIGS. 4 and 6).
A requisite number of thusly protected finned tubes 15 have their opposite endsset in and bonded to conventional header plates. Such a completed core-unit then is secured to conventional tanks 16 with a suitable cross-braces 17 as shown in FIGS. 1 and 2.
A number of such completed heat-exchangers then are ready for shipment and/or storage, as existing conditions require. In either instance these sleeves l2, spaced along each tube serve to prevent satgging of adjacent tubes.
Variations and mod: cations in the details of structure and arrangement of the parts may be resorted to within the spirit and coverage of the appended claims.
1. In a heat exchanger having a core unit formed of a plurality of finned tubes, a sleeve adapted to be mounted on one or more of said finned tubes to prevent radial movement between adjacent tubes, said sleeve comprising, a planar strip of flexible material having a length greater than the circumference of the outer edges of said fins, and a plurality of pairs of closely spaced slits along each edge forming tabs, means for connecting the overlapping ends of said strip for embrasive positioning on the peripheral edges of said finned tube, said tabs being bent inwardly between the fins on said tube to retain the strip in a fixed axial position on said finned tube.
2. In a heat exchanger according to claim 5 wherein a sleeve is mounted on each finned tube, each sleeve being located in a common plane with the adjacent sleeve.