US1410548A - Tubular heat exchanger - Google Patents

Description

(I. A. BROWN. TUBULAR HEAT EXCHANGER. APPLICATION F'ILED MAY 2. 192i.

Patented Mar. 28, 1.922.

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TUBULAR MAT EXCHANGER.

Specification of Letters Patent.

Patented Mar. 28, 1922.

- Application filed May 2, 1921. Serial No. 466,121.

To all whom it may concern:

Be it known that I, CHARLES ANDERTON BROWN, a subject of the King of Great Britain, residing at 19 Hampstead Hill Gardens, London, N. VV., England, have invented certain new and 'useful Improvements in or Connected with Tubular Heat Exchangers, (for which I have filed an application No. 8,715 in England, dated March 19, 1920,) of which the following is a specification.

This invention relates to tubular heat exchangers suitable for cooling water, oil, gas, air, steam or other fluids, or for heating or evaporating such fluids, of the kind composed of tubes or funnels having their ends or one end bulged or expanded in flat sided hexagonal form and fitted and connected together and wherein the interstices between the tube bodies are filled with the fluid to be treated and the active medium is passed through the tubes or vice versa. In such tubular exchangers the tubes are disposed in staggered formation and the fluid stream passes through the interstitial space between any pair of adjacent tubes and strikes against the outer surface of another tube so as to divide the stream and each half stream unites with another half stream from another interstitial space, and so on in progress through the tube block.

The hexagonal end formation is advantageous excepting that with the known regular form the interstitial spacing between the tube bodies has been made the same in the directions normal to the flow of the divided streams and normal to the flow of the full or united half streams, so that the pitch is unnecessarily great in the directions normal to the flow of the divided stream. This results in undue fluid friction in the interstitial spaces owing to frequent changes in the velocity of flow, and in undue volume and weight of the fluid necessary to fill the interstitial spaces. I

According to the present invention, the

advantage of the hexagonal end form is' retained but the arrangement is such that interstitial spacing between the tube bodies in the directions normal to the flow of the divided streams is substantially less than in the direction normal to the flow of the full or united half streams. Preferably the interstitial spacing between the tube bodies in the direction normal to the flow of the divided streams is approximately one half of that in the direction normal to the flow of the full or united half streams.

With this construction for a given amount of heat transferred from the fluid passing through the tubes to the fluid passing through the interstitial spaces or vice versa the frontal area or the area of the tube block measured over the surface containing the end faces of the tubes is reduced; the we1ght of fluid contained in the interstitial spaces is reduced; and the fluid friction and shock loss of the fluid passing through the interstitial s aces is reduced.

These resu ts may be obtained in accordance with the invention either by modification of the hexagonal bulged or expanded ends or by a special construction of the tube bodies.

In order that the invention may be clearly understood and readily carried into effect, I will now proceed to describe the same more fully with reference to the accompanymg drawing in which Figure 1 is a diagrammatic end View of one embodiment of my invention and Figure 2 is a diagrammatic end view of a modified form.

Figure 3 is a sectional view of one of the tubes shown in Figure 1.

Figures 4, 5. 6, 1 views of modified forms of tubes.

Figures 10 and 11 are partly diagrammatic the full streams are shorter than the other four sides which are equal. In-this and the other figures of the drawing the direction of flow in the interstitial spaces is indicated by an arrow. I

In a modification the angles on the opposed corners whose diagonal lies in the direction of flow of the full streams are different from the other four angles which are equal.

In a further modification shown in Figure 2 only the opposite angles are equal and only the opposite parallel sides are equal.

In the constructions shown in Figures 1 and 2 the body of the tube instead of being circular as shown may be made with a crow 8 and 9 are fragmentary section of regular hexagonal form or of one ofthe modified hexagonal forms described above.

In a further'modification particularly applicable to heat exchangers of the type referred to and especially to those described in the specification of my British Patent N 0. 140954 dated 9th July, 1919, the portions of the tube between thebody and the hexagonal end may be made of one or other of" the modified hexagonal forms described above, or the body'of the tube may be modified in a variety of ways, some of which, are given by way of example in Figures 4*9, the bulged or expanded ends 2 being of one of the special hexagonal forms described above.

Referring particularly to the said Figures 49, Figure 4 shows a body portion 1 which is of circular cross section for the middle portion of its length, a bulged or expanded end 2 of one of special hexagonal forms described above, a connecting portion 4 which is gradually tapered and has faces which are inclined to the axis of the tube and a connecting portion 5' averaging to both the hexagonal and circular forms. It will be seen that this connecting portion 5 comprises flat faces 6 and curved or conical faces 7 which alternate with one another around the tube. I

Figure 5 shows a-somewhat similar construction to Figure 4 in which however the connecting and the point 8 is of hexagonal form.

Figure 6 shows another slightly modified form of the tube illustrated in Figure 4 in which the portions 7 are flat and inclined to the axis of the tube.

In Figures 7 and 8 the body 1 of the tube is of duodecagonal form in Figure 7 a portion 8 of hexagonal form leading to the tapered portion 4, and in Figure-8 portions 6 and 7 similar to those described above with. reference to Figures 4 and 5 leading to the portions 4.

In Figure 9 the body 1 which is circular for part of its length has a portion 10 of duodecagonal form with portions7 averaging to both forms and a portion 8 leading from 10 to the tapered portion 4;

any combinations of the forms illustrated in Figures 4 to'9 may be made if desired and are contemplated by my invention and in any of these forms the surfaces other than the hexagonal ends may be made helical if desired.

Figures 10 and 11 illustrate embodiments of the tubes are hexagonal, in Figure 1 the bodies 1 being regular hexagons and the ends 2 irregular hexagons as described above with reference to Figure 1, and the pitch ;0 being less than the pitch P, while in Figure 11 the ends 2 are regular hexagons and the bodies portion 5 between the portion 4 the invention in which the bodies 1 of r 1 irregular hexagons, inthis case the pitch 7) being equal to the pitch P. it will be in width spaces N.

It will be understood that the various embodiment-s of the invention described above are given by way of example only and that many modifications thereof coming within the spirit of the invention may be made. lVhile as pointed out above the invention may be carried out equally by the modification of the hexagonal ends of the tubes or by modification of the tube bodies the former manner of carrying the invention into effect may be considered preferable as thereby the possibility .of the tubes being incorrectly assembled is minimized.

What I claim and desire to secure by Letters Patent of the United States is 2- 1. A tubular heat exchanger composed of tubes having polygonal expanded or bulged ends, the width of the shoulder formed at the junction of each tube bod with the. ex panded end being substantia 1y less in the directions normal to the flow of the divided streams of fluid than the width in the directions normal to the flow of the full or united half streams, substantially as and for the purpose specified. v

2. A tubular heat exchanger composed of tubes having expanded or bulged ends fitted and connected together, the difieren'ce in the radial distance from the exterior surface to the center oft-he expanded end of each tube and the radial distance between the exterior surface and thecentler of the tube body being substantially less in the directions normal to the flow of the divided streams of fluid than the difference in the radial distances between corresponding points in the directions normal to, the fiow of the full or united half streams, substan tially as and for the purpose specified.

3. A tubular heat exchanger composed of tubes having expanded or bulged ends fitted and connected together, the ratio of the difference in the radial distance from the exterior surface to the center of the expanded end of each tube and the radial distance be tween the exterior surface and the center of the tube body in the directions normal to the flow of the divided streams of fluid to the difference in the radial distance between corresponding points in the directions normal to the flow of the full or united half streams being approximately 1:2, substantially as and for the purpose specified.

4. A tubular heat exchanger composed of tubes having polygonal expanded or bulged ends fitted and connected together, the difference in the diameters of each tube body and its expanded end being substantially less in the directions normal to the flow of the divided streams of fluid In both forms than the d'ifierence Lemma in the diameters in the directions normal to the flow of the full or united half streams.

5. A tubular heat exchanger composed of tubes or funnels having their ends expanded or bulged in flat sided form and fitted and connected together without end plates to form a tubeblock, the expanded ends being of such modified hexagonal form that the interstitial spacing between the tube 'bodies in the direction normal to the flow of the divided streams of fluid is substantially less than in'the directions normal to the flow of the full or united half streams, substantially as and for the purpose specified.

6. A tubular heat exchanger composed of tubes having their ends expanded or bulged in flat sided hexagonal form, fitted and connected together, the angles of said expanded ends of the tubes being equal, but the pair of opposite sides which are arranged par-- allel to the direction of flow of the full streams being shorter thanthe other four. sides which are equal.

7. A tubular heat exchanger in accordance with claim 6 characterized by the fact that the angles in the exposed corners whose 9. A tubular heat exchanger composed of tubes having irregular polygonal expanded ends, fitted and connected together, and the body portion of said tubes being of regular polygonal form.

10. A tubular heat exchanger composed of tubes, having irregular polygonal expanded ends fitted and connected together, the body portion of said tube being of regular poly onal form so that their diameters in direc tions normal to the flow of the divided streams are less than the diameters in the directions normal to the flow of the full or united half streams.

CHARLES ANDEBTON BROWN.

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