US2578305A - Fin for heat exchange elements - Google Patents

Description

Dec. 11, 1951 A. P. J. HUET FIN FOR HEAT EXCHANGE ELEMENTS Filed June 3, 1947 Patented Dec. 11, 1951 FIN FOB. HEAT EXCHANGE ELEMENTS Andi- Philippe Jean Huet, Paris, France Application June 3, 1947, Serial No. 752,226 In France April 10, 1946 Section 1, Public Law 690, August s, 1946 Patent expires April 10, 1966 Claims. (Cl. 257-26219) This invention relates to an improved arrangement of heat transfer fins on tubes or other elements of heat exchangers with a view to assuring a better transmission of heat with small draft loss and to assure a rational fiow of the fluid contacting the tubes or heat exchange elements.

The invention will be best understood by consideration of the following description of several illustrative embodiments when read in conjunction with the attached drawings in which;

Figure 1 is a transverse sectional view of a tube provided in conventional fashion with two diametricall opposed longitudinal fins;

Figure 2 represents a tube having two fins on the downstream side of the tube in accordance with the present invention;

Figures 3 and 4 show variations of the construction and location of the fins, Fig. 4 being a perspective view illustrating fiuid guiding passages formed intermediate the surface of the tube and adjacent parts of the fins.

Figures 5 to 7 are transverse sections showing other variations of transverse fins on tubes;

Figure 5A is a partial sectional view on correspondingly designated line in Figure 5; and

Figures 8 and 9 are longitudinal sectional views showing two variations in mountin'guof the fin arrangement shown in Figure 7.

In Figure 1 there is shown a conventional heat exchange tube It] carrying two fins II and I2 diametrically opposite each other located on the axis of the tube and paralleling the exterior current of fiuid which fiows in the direction of the arrow A.

According to a first embodiment of the invention the downstream fin is replaced as is seen in Figure 2 by two fins l3 and I4 spaced laterally and extending in the same direction from the tube substantially tangential to the tube section. The fins l3 and I4 are pierced at longitudinally spaced intervals by slots l5 at their base to permit streams of gas to flow in the direction of the arrow B so as to enter the space situated behind the tube A between the fins l3 and I4 so as to contact the back side of the tube. The slots l5 can be disposed in staggered relation along the length of the two fins.

In Figure 3 the two fins I 3A and A are inclined toward each other with a view to forming behind the tube In a sort of, convergent space l6.

In Figure 4 two upstream fins l1 and I8 are also mounted in the same manner so that the profile of the assembly constituted by the four fins forms a fuseau which is disposed aerodynamically 2 in the fluid stream which fiows in the direction of the arrow A. These fins also present slots or,

apertures l5 at their base which can be staggered on the front and rear fins.

Another variation in construction is shown in Figure 5. The rear fins 20, 2| are made up of parts of half-sections of tubes with one end cut on the bias at 22 and the base of the semi-circular section welded at 23 to the rear surface of the tube ID in such fashion as to form as better seen in sectional view, Fig. 6, a sort of expanding passage 24 between, on the one hand, the undersides of the fins 20, 2| and the outer surface of the tube ill on the other hand. The streams of fluid which fiowing in the direction of the arrow A encounter the tube flow then in the direction of the arrow E beneath the fins and are directed into region It located behind the tube 10 to pass onward in their original direction as indicated by the arrow A.

The passage of the streams of fluid into the restricted orifice 25 at entrance to the expanding passage 24 between the fins 20, 2i and the tube l0 contributes to form zones of altered pressure to the fluid stream which increase the exchange of heat between the exterior fiuid and 211:: which fiows through the interior of the As seen in Figure 6 the forward fins ll, l8 are inclined and also provided with the slots If: as in Figure 4. These slots IS in fins I1, is may be spaced from the regions of the tube on which the rear fins 20, 2| are welded in such fashion that the fluid currents which have already been trapped between the fins l1 and I8 escape freely while other currents of fiuid are drawn into passages 24 formed by the rear fins 2|], 2|.

In the modification shown in Figure 7, the rear fins are formed by plates 30, 3| of metal extending longitudinally of the tube and bent sinuously transversely of their longitudinal axes according to the figure and which create on the rear half of the tube Ill a double venturi 32, the effects of which have just been mentioned. The axis of the Venturi passage 32 is located approximately 45 with respect to the general direction of fiow. The plates 30, 3| can be corrugated in a direction axially of the tube as shown in Figure 8 with the dwell parts 33 welded to the tube in such fashion as to assure the transmission of heat from the fin to the tube while the crests 34 of the corrugations are raised above the tube surface to create the Venturi passages 32.

ingly, spacers 35 hold it from place to place on the tube and assure the transmission of heat.

What I claim is:

1. A heat exchange tube for exposure to gases that flow transversely of its longitudinal axis provided with symmetrically disposed longitudinally extending fins projecting from the tube surface in planes at either side of said axis and formed in the edge portions thereof in contact with the tube with longitudinal slots that form with the tube surface passages converging in the direction of fiow toward the space between said fins for directing streams of fluid into contact with the downstream surface of said tube.

2. A heat exchange tube for exposure to gases that flow transversely of its longitudinal axis provided in planes at either side of said axis with symmetrically disposed longitudinally extending fins projecting from the tube surface on the downstream side thereof and formed with longitudinal slots extending outwardly from the edge portions thereof in contact with the tube with the longitudinal edges of said slots forming with the tube surface to form therewith passages converging in the direction of flow toward the space between said fins for directin streams of fluid into contact with the downstream surface of said tube. I

3. A heat exchange tube for exposure to gases that flow transversely of its longitudinal axis provided with symmetrically disposed longitudinally extending fins projecting tangentially from the tube surface on the downstream side thereof in parallel planes at either side of said axis and formed with longitudinal slots extending outthe said passage formed by one fin is oflset' longitudinally of the tube from the passage formed in the fin spaced laterall therefrom on the tube.

5. A finned tube as defined in claim 1 in which pairs of fins are provided on both the upstream and downstream faces of the tube and the said passages formed by the downstream fins are offset longitudinally of the tube with respect to passages formed by the upstream fins.

ANDRE PHILIPPE JEAN HUET.

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

UNITED STATES PATENTS Number Name Date 2,019,913 Kotrbaty Nov. 5, 1935 2,330,065 Lucke Sept. 21, 1943 2,371,144 Bronander Mar. 13, 1945 2,400,157 Merry May 14, 1946 OTHER REFERENCES Serial No. 300,820, Beck (A. P. C.), published May 25, 1943.

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