US2697588A - Interlocking finned heat exchange envelope - Google Patents

Description

Dec. 21, 1954 A. JENSEN INTERLOCKING FINNED HEAT EXCHANGE ENVELOPE Filed Aug. 4. 1950 on 00000 cocoon 0000c ri/wr dense/5 BY l 2 w 8 An S a a M 0 a 3 0/ 4 n l w p. m m H. w a m u p p. m P, (I y L .4 Jr 11 i r l United States Patent WTERLOCKING FINNED HEAT EXCHANGE ENVELOPE Arthur Jensen, Wellsville, N. Y., assignor to The Air Preheater Corporation, New York, N. Y.

Application August 4, 1950, Serial No. 17 7,579

9 Claims. (Cl. 257-245) The present invention relates to improvements in plate type heat exchange apparatus and particularly to those in which one of the fluids flows through the exchanger under high pressure.

A well known form of heat exchange apparatus for the transfer of heat between two confined fluids is made up of a plurality of spaced metallic plates forming passages through alternate ones of which a heating fluid, such as a hot gas, flows in heat exchange relationship with the fluid to be heated, such as air, traversing the intermediate passages. In many such exchangers a series of envelopes are provided consisting of parallel plates with the space therebetween closed along one pair of opposite edges to bound the sides of the passage for one of the fluids such as air to be heated. The envelopes are mounted in spaced parallel relation to form the passages for the other fluid or heating gas and the inter-envelope spaces are likewise closed along one pair of .opposite side edges of the envelopes, which sides may be those extending parallel to the closed edges of the air envelopes in case of parallel flow, or along the adjacent sides in case of transverse flow. Such spaced envelopes form a core that is usually enclosed within a housing which, when one of the fluids is under high pressure, involves the employment of an expensive and heavy outside shell to withstand the pressure.

An object of the present invention is to construct a heat exchanger of the type mentioned above by forming and joining the envelopes together in such a way that they strengthen and support each other and so as to render it unnecessary to also utilize a heavy and expensive housing.

The invention will best be understood upon consideration of the following detailed description of illustrative embodiments thereof when read in conjunction with the accompanying drawings in which:

Figure 1 is a diagrammatic view in longitudinal section of a plate type heat exchanger embodying the present invention and illustrates the manner of forming the air envelopes and rigidly connecting them together to create a heat exchanger.

Figure 2 is a fragmentary sectional view along the line 22 in Figure 1 showing part of the heat exchanger.

Figure 3 is a sectional view on the line 3-3 in Figure 2; and

Figures 4, 5 and 6 are fragmentary views similar to Figure 2 showing alternative constructions for forming and joining the parallel envelopes into a heat exchanger.

Referring first to Figure 1, a fluid under low pressure, such as hot gas, is admitted to the heat exchanger, designated as a whole by the numeral 10, through an inlet connection 11 and distributed by the manifold 12 to a series of gas passages 13 (Fig. 2) disposed in alternation with the passages 14 through which is circulated a fluid under high pressure, such a air to be heated. Header plates 15 and 16 in the inlet manifold 12 and the outlet manifold 17 have parallel slots leading to the gas passages and intermediate imperforate portions that close the end of the air passages 14 so that the heating gas in flowing longitudinally of the exchanger is confined to the gas passages 13 before it is discharged from the manifold 17 through the outlet connection 18. The other fluid, which may be air under high pressure, enters the heat exchanger 10 through the side inlet connection 20 and is directed into the air passages 14 by guide vanes 21 and is discharged through an outlet connection 23,

2,697,588 Patented Dec. 21, 1954 the air'entering and leaving the air passages 13 at locations adjacent opposite ends of the exchanger through the sides of the passages at these points. The foregoing general construction is conventional.

As mentioned above the heat exchanger is made up of a plurality of envelopes designated as a Whole in Figure 2 by the numeral 30. Each of these envelopes comprises a pair of parallel metallic plates 32 and 33 spaced to form an air passage 14, the envelopes being mounted in spaced relation to form therebetween the gas passages 13. Metal bars or strips 34 mounted between the plates 32 and 33 are welded thereto along their side edges to close the sides of the air passages. Near the ends of the exchanger parts of these metallic strips are omitted at the bottom of each envelope opposite the air inlet 20 and at the top of the envelopes opposite the air outlet 23 so that air may be admitted to and taken from the envelopes which define the air passages 14 alternating with the gas pas-' sages 13.

To improve the transfer of heat from the hot gas flowing in the passages 13 through the walls 32, 33 to the air flowing in the passages 14 the walls are provided with extended surfaces in the form of pin fins 35 bonded in good heat transfer relationship to the surfaces of the plates 32 and 33 that confront the air passage 14 within an envelope 30. As disclosed in greater detail in the copending application of Peter Hodson and Sven 'Holrn Serial No. 152,952 filed March 30, 1950 the pin 'fins 35 are parts of metallic wires bent sinusoidally to form a seriesof substantially U-shaped loops whose leg portions 36 (Fig. 3) constitute the pin fins while the intermediate yokes or stretcher portions 37 are engaged in mounting channels 38, the wires being brazed to the channels 38 and the latter to the surfaces of the plates 32 and 33 bounding the air passages within the envelopes.

On the gas side the plates 32, 33 forming the envelopes 30 are provided with a plurality of parallelly spaced, longitudinally extending channel members 40, 41 which constitute extended surfaces of these walls into the gas passages for improving the efliciency of the heat transfer from the gas to the walls 32, 33 and through the latter to the air on the opposite sides thereof. To maintain the envelopes in desired spaced relationship and to tie them rigidly together the legs 42 of the spaced channel members 40, 41 are provided along their longitudinal edges with laterally extending flanges or lips 43 that engage and interlock with the similar flanges on the channels of the adjacent envelopes. The envelopes assembled in the relationship described may be formed into an integral monolithic core by brazing the interlocked lips 43 of the channels together to provide for the interlocking relationship. It should be noted that the lips 43 on the velopes extend in the opposite direction, as downwardly, so that when several envelopes are juxtapositioned the lips 43 on the two sets of channels interlock with each other. Nevertheless, all of these channels may be formed in the same manner so that they are duplicates, the reversed relationship being produced simply by turning the channels on one side of an envelope end for end with respect to those on the other side of the envelope so that their lips extend in opposite directions, as upwardly in one case and downwardly in the other. The spaces between adjacent envelopes are closed along their upper and lower longitudinal side edges by the narrow metallic strips 44. These strips in addition to joining the envelopes together along their longitudinal side edges form the longitudinal closure members for the sides of the gas passages 13 between the envelopes which alternate with the air passages 14 within the envelopes. Together with the strips 34 that close the corresponding sides of the envelopes the strips 44 constitute the top and bottom walls of the heat exchanger. Plates 47 forming closuresfor the sides of the heat exchanger are joined along their upper and lower longitudinal edges to the outermost longitudinal strips 46 at the sides of the assembled envelopes, the exchanger thus requires no separate shell to enclose it. To this heat exchanger consisting of a series of rigidly assembled, spaced envelopes the inlet and outlet manifolds 12, 17 for the two fluids may be connected in any suitable manner this not being a special feature of the present invention.

In Figure 4 the channel members which are designated 50 are provided with generally T-shaped side legs 51 so that lateral flanges extend in both directions from opposite longitudinal edges of the channel legs. The lateral flanges 52 are chamfered on their under sides thus producing an undercut slot facing the base of each channel so that a mortise or dovetailed interlocking arrangement is provided by the channels. Each channel on one plate interlocks with two on the other plate, these channels not being directly opposite but offset to either side.

In Figure the channel members 60 are also offset and have their interlocking lips formed by curling over the outer edges of the leg portions to provide a hook-like interlocking arrangement consisting of a re-entrant groove 61 along the edge of each channel leg 62 receiving the curled-over longitudinal edge portion 63 of the associated channel on the adjacent envelope.

In Figure 6 the means for connecting and spacing the adjacent envelopes 30 are separate from other channel members 70. Here there are provided on the outer wall surface of the envelopes longitudinally extending members 71 having flange portions 72 and 73 bent inwardly and downwardly towards each other to form a groove, like the slot in Fig. 4, for receiving the roughly T-shaped end 74 of a tie member 75 which in section resembles an I-beam. The members 71 also are to be considered as channel form surface extending fins on the walls confronting the gas passages.

Although the gas passages 13 have been shown as paralleling the air passages 14 it will be understood that cross-flow of the fluids might be employed, in which case the channels 40, 41 etc. would extend transversely of the envelope plates rather than parallel with the wire fin elements.

What I claim is:

1. In a heat exchanger for two confined fluids including envelope components each comprising parallelly spaced plates joined along one pair of opposite side edges to form within each envelope a passage for one fluid with the envelope components disposed contiguously in spaced parallel relation; heat transfer fin elements consisting of channel members bonded in spaced parallel relation to the outer wall surfaces of each pair of contiguous envelopes and projecting therefrom toward each other and formed with laterally projecting lip portions interlocking with channel lip portions of channels on contiguous envelopes so as to join the envelopes together; and closure means joining contiguous envelopes along one pair of opposite side edges to form side walls for the passages for said other fluid between the envelopes.

2. A heat exchanger as recited in claim 1 wherein the channel members are of substantially U-shape with straight legs provided at their distal ends with lateral flanges.

3. A heat exchanger as recited in claim 1 wherein the channel members are of substantially U-shape with straight legs each provided with T-shaped distal ends chamfered on the underside of the T cross-bar.

4. A heat exchanger as recited in claim 1 wherein the channel members are of substantially U-shape with straight legs provided at their distal ends with lateral flanges extending at right angles.

5. A heat exchanger as recited in claim 1 wherein the channel members are of substantially U-shape with straight legs provided at their distal ends with lateral flanges extending at right angles in the same direction from both legs.

6. A heat exchanger as recited in claim 1 wherein the channel members are of substantially U-shape with straight legs each provided at its distal end with a lateral flange which extends in the same direction from both legs at right angles thereto.

7. A heat exchanger as recited in claim 1 wherein the sides of the channel members are inclined toward each other to provide an undercut slot therebetween; and an I-beam member engaged in the slots of channel members on contiguous envelopes to interlock the latter.

8. A heat exchanger as recited in claim 1 wherein the distal ends of the channel members are hook shaped.

9. In a heat exchanger provided with inlet and outlet connections leading to passages for two confined fluids arranged in alternation and including envelope components each comprising plates spaced parallelly to form within the envelopes the passages for one fluid with the envelope components disposed contiguously in spaced parallel relation to form therebetween passages for the other fluid; heat transfer fin elements consisting of channel members bonded to the outer wall surfaces of each pair of contiguous envelopes and projecting therefrom toward each other with their distal ends formed with interlocking lateral lip portions so as to rigidly join the envelopes together; closure means joining the plates of each envelope along one pair of opposite side edges; and closure means joining contiguous envelopes together along said one pair of opposite side edges to form side walls for the passages between the envelopes for said other fluid and acting to maintain said channel members interlocked by spreading said plates, both said closure means constituting parts of opposite walls forming the casing structure of the exchanger.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Country Date Great Britain Feb. 3, 1944 Number Number

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