US 3783938 A
A heat exchanger comprises at least one tube containing at least one flow directing turbulence member disposed longitudinally therein and comprising a thin metal strip having at least one row of longitudinally spaced wings struck angularly therefrom and extending in the same direction longitudinally, said wings each having an aperture therein and being disposed at an obtuse angle alternately on opposite sides of the strip and resiliently engaging the inner wall of the tube.
Claims available in
Description (OCR text may contain errors)
Unite States Patent [191 Chartet [4 1 Jan. 8, 1974 DISTURBING DEVICE AND HEAT EXCHANGER EMBOBYRNG THE SAME  Inventor: Andr Chartet, Meudon, France  Assignee: Societe Anonyme Des Usines Chausson, Asnieres, France  Filed: Jan. 11, 1972  Appl. N0.: 216,925
 Foreign Application Priority Data Jan. 28, 1971 France 710288  U.S. Cl 165/166, 138/38, 165/179  lint. C1 F2811 3/02  Field of Search 138/38, 39; 165/179, 165/166  References Cited UNITED STATES PATENTS 2,359,288 10/1944 Brinen 138/38 2,691,991 10/1954 Schutt et a1 138/38 Primary Examiner-Charles J. Myhre Assistant Examiner-Theophil W. Streule, Jr. Attorney-lmirie and Smiley [5 7] ABSTRACT A heat exchanger comprises at least one tube containing at least one flow directing turbulence member disposed longitudinally therein and comprising a thin metal strip having at least one row of longitudinally spaced wings struck angularly therefrom and extending in the same direction longitudinally, said wings each having an aperture'therein and being disposed at an obtuse angle alternately on opposite sides of the strip and resiliently engaging the inner wall of the tube.
10 Claims, 8 Drawing Figures DISTIIIIIEING DEVICE ANE HEAT EXQIIANGER IEMBODYING THE SAME BACKGROUND OF THE INVENTION It has been proposed to provide turbulence members within a tube of heat exchangers to create turbulence of fluid flow through the tube to increase the rate of heat exchange between the fluid and the tube. These turbulence members do not necessarily provide the desired effect because such strong turbulence is developed in the inlet portion of the tube that the major portion of the heat exchange is concentrated at such inlet portion and consequently results in substantial variations in temperatures longitudinally of the tube. Moreover, the turbulence members comprise baffles which not only create excessive turbulence but also restrict the rate of fluid flow through the tube. Finally, the presently known turbulence members must be rigidly secured within the tube by soldering, brazing, or the like and this substantially increases production costs.
SUMMARY OF THE INVENTION This invention relates to heat exchangers and more with turbulence members. The invention enables The embodiment of this invention makes possible to very substantially increase in the heat dissipation of the tube without practically increasing the losses of fluid pressure. The invention enables regulation of heat dissipation be substantially homogeneous all along a tube or rather great length, i.e., several tens of centimeters long, even with a low fluid flow inside said tube.
An additional advantage of the invention consists in the fact that the turbulence member of members of an exchanger tube can be positioned very easily without requiring a subsequent soldering or brazing.
According to the invention, the turbulence member is placed inside an heat exchanger tube and is constituted by a thin metal strip having at least one row of longitudinally spaced wings, free on three sides, dis posed angularly from said strip, the wings each having an aperture to permit flow therethrough, the free edge portion of each wing being angularly disposed to the plane of the respective wing to engage in heat exchange contact with the inner wall of the tube.
FIG. 1 is a perspective view of a portion of turbulence member embodying the invention;
FIG. 2 is a top plan view of a portion of the turbulence member showing an additional characteristic of the invention;
FIG. 3 is a perspective view of a portion of turbulence member substantially similar to the one of FIG. 2 and showing an additional development;
FIG. 4 is a cross-sectional view of a heat exchanger tube embodying the turbulence member of the invention;
FIG. 5 is an. enlarged longitudinal section taken on line 5-5 of FIG. 4 and showing a special effect obtained by the turbulence member of the invention;
FIG. 6 is a partial sectional view showing a detail of embodiment;
FIG. '7 is a diagrammatic longitudinal sectional view of a heat exchanger according to the invention, and
FIG. 8 is a sectional view substantially similar to FIG. 7 of another heat exchanger.
DETAILED DESCRIPTION OF THE INVENTION FIG. I shows the turbulence member according to the invention in the simplest embodiment thereof. Said turbulence member is formed from a thin metallic strip I having spaced openings 2, 3 in two parallel rows, for example, though any desired number of rows can be provided. In fact, depending on the composition of the exchanger tube wherein the turbulence member is to be placed, the number of rows of openings 2, 3 can be limited to one or also can be more than two.
The metal cut in forming the openings 2 and 3 is bent to be disposed at an obtuse angle to the plane of the strip and define wings 4, 40, free on three sides, said wings having apertures 5 to permit fluid flow therethrough, the free edge portion of each wing being bent to define a flange 6 for bearing in heat exchange relation against the inner wall of a surrounding tube 7 as shown in FIG. 5. When positioned in a tube, the turbulence member constitutes an intermediate partition within the tube, said partition being perforated by the openings 2, 3. The wings l, 4a constitute elements introducing only a very small loss of pressure, due to the apertures 5 extending almost from the angle portion 8 of the wing to the flange a bearing against the tube wall and consequently opposing only the thickness of the metal surrounding the aperture to fluid circulation which flows in the direction of arrowfFIGS. 6-8. Thus a gentle turbulence is produced which increases heat exchange uniformly along the length of the tube, the flow being along an undulatory path at the level of the tube Wall without noticeable loss of pressure.
FIG. 2 shows an additional characteristic wherein the turbulence member is provided, between the openings 2, 20 from which are formed the spacers, with transverse slots 9 and lateral slots M), II in succession. Said openings and slots further reduce losses of pressure due to the turbulence member because, the surface area of the turbulence member is reduced and consequently reduces the losses of pressure due to friction. Besides, the alternate arrangement of the openings and slots cause the fluid in circulation in of 7 to follow various directions, thus improving the turbulence of said fluid.
The sizes and spacing of the openings and slots in successively aligned turbulence members can vary to adjust the quantity of dispersed heat all along tube 7.
The present turbulence member can be placed in tube 7 without the necessity to solder or braze it to the inner wall of said tube because the flanges 6 constitute bearing surface of sufficient size to ensure a good heat transmission with the wall of tube 7. In view of making said bearing as firm as possible and also for avoiding any risk for the turbulence member being to be moved inside the tube, as shown on FIG. 6 the wings 4, 4a, upon manufacturing, are disposed at an angle greater than required. Thus, when the turbulence member being is engaged in the tube by moving in the direction of arrow f the wings are slightly depressed, with the flanges a bearing against the inner wall of said tube. It is to be noted that the angle of the wings is directed in the line of flow indicated by the arrow f thus the pressure applied on the wings by the fluid in circulation tends to buttress the wings against the tube wall.
For a good maintaining of the turbulence member in the tube, it is advantageous, as shown on FIG. 1, that the wings of two rows be alternately bent from opposite sides of the strip thus improving turbulence of the fluid in circulation.
FIG. 3 shows an additional development wherein the lateral edges of the strip I are bent to define longitudinal flanges 12, which rigidifies the turbulence member and facilitates its introduction into the tube 7 with the flanges 12 bearing against the lateral sides of the tube as shown on FIG. 4.
FIG. 7 shows a heat exchanger according to the invention constituted by a tube 8 containing a plurality of turbulence members positioned for dissipating a quantity of heat substantially uniformly along the whole length thereof.
The exterior of the tube 7 may be provided with heat dissipators 13 and contains in the upstream portion thereof, while considering the direction of the liquid circulation indicated by arrow f,, a first turbulence member 1 of which the wings 4 are spaced a maximum distance, which means that said first turbulence member is as shown in FIGS. 2 or 3, with transverse and lateral slots 9, 10, 11 of an maximum width.
The tube 7 contains also a second turbulence member 1 aligned with the first one but of which the spacers 4 are more closely spaced by reducing the width of slots 9, 10, 11. The tube 7 is then provided with a third turbulence member i constituted as shown on FIG. 1, thus not having slots 9, l0, 11.
Consequently, the fluid in circulation in tube 7 becomes more and more turbulence, which equalizes the heat dissipation even for low fluid flows.
FIG. 8 shows the embodiment of another heat exchanger including two tubes 7,, 7 which are both provided with heat dissipators 13. The tube 7 is placed at the upper portion of the exchanger and contains a turbulence member la which can be constituted as above described with reference to FIG. 7. In a like manner, the tube 7 contains a turbulence member 1b. However, it is advantageous, as shown in the drawings, that the wings of the turbulence member or turbulence members 1b be closer than wings of turbulence member or turbulence la, thus enabling the tube 7 to dissipate a greater quantity of heat than tube 7.
Such an arrangement has an advantageous application in the embodiment of heat radiators for motor vehicles wherein the lower portion of the interior of the vehicle should receive more heat than the windshield. When such requirement becomes particularly desirable, then, as shown in the drawings, the heat dissipators 13 of the tubes 7 and 7 are further separated by a partition or a screen 14 which can be constituted by a thin metal sheet but which is preferably made of plastics material or other insulating material, to provide separate exchanger circuits constituted by tubes 1a and 1b. Also in addition, the outer heat dissipators of tubes 1a and lb can be covered by sheets 15, 16 respectively, thus defining guiding passages for the medium to be heated or cooled by the fluid in circulation in the tubes 7,, 7
It would not be obviously departing from the scope of the invention while constituting an heat exchanger provided with more than two circulation tubes, said tubes being also provided with the present turbulences members which extend through only one portion of the tube length.
1. A heat exchange device comprising at least one tube having at least one flow directing turbulence member disposed therein and extending longitudinally of said tube, said member comprising a thin metal strip having at least one row of longitudinally spaced wings out free on three sides and disposed angularly from said strip and in the same longitudinally, said wings each having an aperture therein and being disposed at an 0btuse angle alternately on opposite sides of the metal strip and resiliently engaging the inner walls of the tube.
2. A device as set forth in claim 1 wherein the strip is provided with two rows of longitudinally spaced wings in transverse alignment and longitudinally zigzagged.
3. A device as set forth in claim 1 wherein said strip has slots between said wings.
4. A device as set forth in claim 3 wherein said slots include transverse slots and lateral slots disposed alternately between the said wings.
5. A device as set forth in claim 1 wherein the free edge portion of each wing is angularly disposed to constitute a flange in heat exchange contact with the inner wall of the tube.
6. A device as set forth in claim 5 wherein the aperture in each wing extends to the inner edge of said flange.
7. A device as set forth in claim 1 comprising a plurality of separate turbulence members longitudinally aligned within the tube, said turbulence members successively having more closely spaced wings from inlet to outlet of said tube.
8. A device as set forth in claim 1 wherein the thin metal strip is provided along both sides thereof with longitudinal flanges contacting the inner walls of the tube.
9. A device as set forth in claim 1 comprising at least two tubes, heat dissipators being provided outerly on said tubes, and said tubes being piled one on another and containing turbulence members with unequally spaced apertured bent portions.
10. A device as set forth in claim 9 further comprising at least one screen separating the heat dissipators of the piled tubes whereby differentiating the two heat exchange circuits constituted from said piled tubes.