US2650077A - Heat exchanger envelope comprising assembled channels and plates - Google Patents

Description

w. E. HAMMOND ET AL HEAT EXC ER ENVELO ASSEMB File Aug. 25, 1953 PE COMPRI I G CHANNELS AND- PLAT d June 8 1951 d fl y mm Q m W50 7 M2 C V. B

Patented Aug. 25, 1953 HEAT EXCHANGER ENVELOPE COMPRISHVG ASSEMBLED CHANNELS A ND PLATES William E. Hammond, Wellsville, and Clayton A. Ballard, Belmont, N. Y., assignors to The Air Preheater Corporation, New York, N. Y.

Application June 8, 1951, Serial N 0. 230,544

4 Claims.

The present invention relates to improvements in plate type exchangers utilized for the transmission of heat between two confined fluids and particularly to an improved "envelope component to be assembled in multiples in forming such a heat exchanger.

A well known type of 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 relatively hot gas flows in heat exchange relationship with air'or other fluid to be heated that traverses the intermediate passages. In many such exchangers a series of fenvelopes are provided each consistin of a pair of parallel plates with the space therebetween closed along one pair of opposite edges to bound the sides of the passage for oneof the fluids such as air to be heated. The envelopes are mounted in spaced parallel relation to form therebetweenv 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 ofthe 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 with which are associated the inlet and outlet manifolds and the supply and discharge ducts for the two fluids.

' To increase the heat transfer efliciency heat exchangers of thistype" frequently have the walls of the fluid passages provided with extended surface in the form of fins projecting from the plates forming the passage walls into the path of the fluids and serving to increase the conduction of heat to and through the walls bounding the passages. In the application of Sven I-Iolm, Serial No. 752,008, dated June 3, 1947, now Patent No. 2,595,457, dated May 6, 1952, there is disclosed a form of extended surface for passage walls comprising pin-like fins extending between the walls bounding the gas passage. on the opposite face of these walls extended surface is provided in the form of channel members extending parallel to the direction of air flow. To promote suflicient heat transfer good bonds have to be provided between the pin fin elements on the inner walls of the gas passage and also between the outer walls of this passage and the channel members and such bonds have heretofore been provided by brazing.

The present invention is directed to an improved plate assembly that forms the passage walls and the fin elements that constitute extended surface from these walls so as to form an integral heat exchange envelope.

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 perspective view of a heat exchanger envelope composed of a series of structural elements assembled and bonded together in accordance with the present invention;

Figure 2 is an end view of the envelope shown in Figure 1 and Figure 3 is a View similar to Figure 1 of a modified form.

The heat exchanger envelope shown in Figure 1 is made up of two parallel rows of U-shaped channel members I 0 assembled in side by side relation in rows 50 that the bases 12 of the channels aline to form the walls of the fluid passage l4 within the envelope. The side legs I6 of the channel members are spaced apart and interposed between the latter are plates 20 that project from the passage walls so as to subdivide the latter, the longitudinal edges 22 of the plates 20 being in the plane of the longitudinal edges 24 on the end faces of the legs 01 the channel members so that the plates and channels may be welded into a unitary envelope by forming welds longitudinally along the alined faces of the channel legs l6 and plates 20. The channel legs l6 and parts of plate 20 between them constitute longitudinal or strip fins in the air passage. Tabs 32 bent from perforations 34 in the plates 20 provide additional surface in the gas passage for absorbing heat and conducting it through parts of the plates 20 to the walls of the gas passage constituted by the bases l2 of channels to. As shown in Figure 1 the row of openings 34 is punched in a plate 20 so that the lower marginal edges of the plates 32 lie below the base l2 of the channel member in order that the fin tabs 32 may be symmetrically located in the gas passage.

The arrangement in Figure 3 is similar except that rows of perforations 31 and 3B are formed in staggered relation in the plates and the tabs 40 are bent from the lower margins of the perforations 31 so as to lie in the same plane as and aline with the tabs 42 struck from the upper edges of the perforations 38.

The staggered arrangement of perforations in Figure 3 has the advantage of enabling the formation of longer fin tabs 40, 42 while at the same time maintaining the tabs located in a central plane in the passage. This increased tab length is possible since the perforation from which a tab is struck may be of greater height than in Figure 1 and be overlapped further by the legs or flanges of the adjacent channels.

Along the longitudinal side edges of the envelopes imperf-orate plates such as indicated at 36 in Figure 3 would be utilized to close the side of the gas passages. By mounting a series of envelopes in spaced relation aplate heat exchanger may be formed with alternate passages for gas and intermediate passages for air. These passages being connected at their ends to manifolds which divide the air and .gas into streams flowing within the interior of the envelopes and within the spaces between them respectively.

What We claim is:

l. A heat exchanger envelope comprising a contact with the outer faces thereof and projecting beyond the bases of the channels in .said row to extend between the side legs of similar channel U-shaped members disposed in .inverted relation in the opposite row with the end faces of said plates located in the plane of the longitudinally extending end faces of the legs of the channel members in both rows; and longitudinal welds along the end faces of said plates and channels uniting them toform a unitary envelope with longitudinal fins on its outer Walls constituted by the legs of said channel members and the intervening portions of said plates.

2. A heat exchanger envelope comprising a plurality of U-shaped metallic channel members mounted in closely spaced side by side relation so that the channel bases aline in each row to form opposite wall of a fluid passage within the envelope and disposed in two parallel rows with their bases in confronting relation to form the boundary wall of said passage and with their legs extending from the :outer faces of the envelope as longitudinal fin parts; plane plate members interposed between the side legs of adjacent channel members in one row in contact with the outer faces thereof and projecting beyond the bases of the channels in said .row to 4 extend between the side legs of similar channel U-shaped members disposed in inverted relation in the adjacent row with the end faces of said plates located in the plane of the longitudinally extending end faces of the legs of the channel members in both rows; and longitudinal welds joining along the end faces of said plates and channels forming a unitary envelope with longitudinal fins on its outer walls constituted by the legs of said channel members and the intervenin portions of said plates.

3. A heat exchanger envelope comprising a plurality of U-shaped metallic channel members mounted in closely spaced side by side relation in upright and inverted relation in either of two parallel rows so that the channel bases aline in each row .to form parts of opposite walls of a fluid passage located between the two rows of channel members; plane plate members interposed between the side legs of contiguous upright U-shaped channel members in one row in contact with the outer faces thereof and projecting beyond the .bases of the channels in said .row to extend between .the side legs of similar :channel U-shaped members disposed in inverted relation in the opposite row with the end faces of said plates located in the plane of the longitu dinally extending end faces of the legs of the channel members in both rows; and longitudinal welds along the end faces of said plates and channels uniting them to form a unitary envelope with longitudinal fins on its outer walls constituted by the legs of said channel members and the intervening portions of said plates; and rows of tabs punched from the material of said plate members and extending therefrom into the passage formed by said rows of said channel members.

4. A heat exchanger envelope as defined in claim 3 wherein the tabs punched from the plate material are bent to lie in a plane paralleling the passage walls and extend into the passage from opposite margins of perforations arranged in staggered relation in parallel rows extending longitudinally of said vplates.

WILLIAM E. HAMMOND. CLAYTON A. BALLARD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,705,471 De Beauvais Mar. 19, 1929 1,775,819 Fischer et al Sept. 16, 1930 2,321,110 Shipman June 8, 1943

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