Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F3/00—Plate-like or laminated elements; Assemblies of plate-like or laminated elements
  • F28F3/02—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations
  • F28F3/04—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations the means being integral with the element
  • F28F3/042—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations the means being integral with the element in the form of local deformations of the element
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D9/00—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
  • F28D9/0025—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being formed by zig-zag bend plates

Definitions

• This invention relates to a low profile heat exchanger module for use in heat furnaces, steel melting furnaces, gas turbines which use recuperators and the like, and a method for forming the same.
• the present invention is directed to a low pro ⁇ file heat exchanger module made from one or more compact, single sheet primary surface heat exchanger core units.
• Each unit is formed from a single sheet of thin material which has been pleated to any depth desired. Before pleating, the longitudinal edges of the thin sheet are serrated to provide fluid en ⁇ trance ramps that minimize blockage, and the surface of the sheet is embossed to define flow passages and provide a means for directing flow and controlling turbulence.
• Figure 1 is a plan view of a portion of a single sheet of heat exchange material employed to form the heat exchange core of the present invention
• Figure 2 is a plan view of a portion of the single sheet of Figure 1 after embossing to show a "U" flow concept.
• Figure 2* is a plan view of a portion of the single sheet of Figure 1 after embossing to show a "Z" flow concept.
• Figure 3 is a view in side elevation of the single sheet of Figure 2 during the pleating thereof;
• Figure 4 is a diagrammatic illustration of a side view of a pleated assembly of the present inven ⁇ tion
• Figure 5 is a diagrammatic illustration of an end view of a pleated assembly of the present inven ⁇ tion
• Figure 6 is a cross sectional view of the heat exchanger module of the present invention
• Figure 7 is a diagrammatic illustration of an end view of the heat exchanger of the present invention
• Figure 8 is a plan view of a portion of a single sheet of heat exchange material of a second embodi ⁇ ment of the present invention
• Figure 9 is a view in side elevation of the single sheet of the embodiment of Figure 8;
• Figure 10 is a view in side elevation of the single sheet of the embodiment of Figure 8 during
• Figure 11 is a diagrammatic illustration of a third embodiment of the present invention.
• Figure 12 is a diagrammatic illustration of the method of producing the embodiment of Figure 11.
• Figure 1 illustrates a single sheet used to form one of the pleated assemblies of the heat exchanger module of the present invention.
• the single sheet indicated generally at 10, is a long rectangular strip of heat exchange material, for example a suit ⁇ able thin metal, such as heat resistant steel.
• the width of the sheet 10 indicated at 12 determines the length of the resulting pleated assembly, and may be varied by the designer to fit the desired heat exchanger application.
• the longitudinal edges of the sheet are serrated' or cut in a sawtooth pattern so that the distance 14 between notches 16 is about equal to the desired height of the pleated assembly.
• the apexes or points of the serrated edge are shown at 18, and the distance of an edge 20 extending be ⁇ tween notch 16 and point 18 should preferably be equal to the height of the pleated assembly as indi- cated at 14 to eliminate fluid flow blockage.
• the assembly may be about 1-2 inches in height at 14 and the width 12 may be about 6-7 inches.
• the configuration of the serrated edges of the sheet 10 can be altered to meet varying structural requirements.
• the apexes 18 may be rounded instead of pointed, and the edge 20 can be curved rather than straight.
• the pleated assembly is formed in a manner de- picted in Figures 2 and 3 or 2' and 3.
• the serrated sheet of heat exchange material 10 is divided into sections or walls 22 and 24 whcih are embossed by means of conventional dies, shaped rollers or any other embossing techniques;.
• the embossing serves to separate the subsequently formed pleats of the heat exchanger accurately and to guide the fluid flow through the completed heat exchanger.
• the em ⁇ bossing may space the pleats for a distance of about .030 inches.
• each section 22 and 24 may be embossed in a U-shaped or Z-shaped configuration respectively as shown by the rows of bosses 26 on section 22 and the rows of bosses 28 on section 24. While only four rows of bosses 26 and four rows of bosses 28 are shown, the number of rows could be much higher and is limited only by the size of the sections 22 and 24.
• Fluid flow channels 27 are defined on ' the face of each section 22 and 24 between the rows of bosses 26 and 28. The interruptions between bosses in a row induce fluid turbulence in the flow path defined thereby and thus enhance the heat transfer characteristics of the pleated assembly formed from the sheet 10.
• the sheet 10 will be pleated into a pleated assembly which forms part of the core of the heat exchanger module depicted in Figure 6, it is necessary to emboss the sheet so that the pleats are spaced far enough apart to allow fluid flow between them. This is accomplished by embossing sections 22 and 24 in opposite directions. Thus in Figure 2, the bosses 26 on section 22 project upwardly, while the bosses 28 on section 24 project downwardly. This alternate arrangement is maintained throughout the
• the sheet 10 is pleated by folding it along lines or crest portions 34 between the sections or walls 22 and 24.
• Pleat- ing may be accomplished mechanically in any conven ⁇ tional manner, such as on machines utilizing dull- edged knife blades like those used for pleating filter paper in the manufacture of air cleaners and oil fil ⁇ ters, but which have been modified to pleat thin metal or heat exchange material rather than paper.
• Figure 3 shows the embossed sheet 10 being pleated and compressed at the lower end 36 to form the pleated assembly shown in Figure 4.
• the sections 22 and 24 of the sheet are compressed together until the raised bosses 26 and 28 contact the next adjacent section of the sheet.
• the height of such bosses accurately controls the spacing between adjacent sections when the sheet 10 is pleated and compressed.
• the heat exchanger module 46 of the present invention may be formed by stacking at least two pleated assemblies 38 within a housing 48 as shown in Figure 6.
• the upper pleated assembly 38a is placed over the lower pleated assembly 38b with a spacer 50 between them.
• the spacer 50 is essentially either a solid sheet or a mesh or perforated strip and is shown extending along the entire length of line 34 between sections of the pleated assemblies from point 52 to point 54. However, the spacer 50 may be placed so that it stops short of points 52 and 54.
• edges 20 It is possible, by varying the thickness and the length of the spacer 50, to reduce fluid flow blockage be ⁇ yond the reduction achieved by means of the fluid entry ramps defined by edges 20. As previously men ⁇ tioned in discussing Figure 1, the length of edges 20 should be equal to pleat depth 14 to minimize fluid flow blockage. Although the ramps are shown to be straight, longer ramps may be achieved within the same dimensions by curving edges 20, thus length ⁇ ening the ramps while maintaining the compactness of the unit.
• Hot and cold fluid manifolds are attached to the ends of the two stacked pleated assemblies as shown in Figure 6, and result in a low profile heat exchanger.
• Inlet manifolds 56 provide hot fluid, for example hot exhaust gas from a gas turbine, through fluid passages 58. This hot fluid follows the path shown by the white arrows 58 to outlet manifolds 60 which collect the previously hot fluid after heat has been transferred therefrom in the heat exchanger ⁇ ore. Since the heat exchanger of the present inven ⁇ tion is a counterflow type heat exchanger, cool fluid, as, for example air from the compressor of a gas turbine engine, is supplied to the path shown by arrows 64 by a cool fluid inlet manifold 62.
• This cool fluid flows through the pleated assemblies 38a and 38b along the paths indicated by the dark arrows, is heated, and then is collected by an outlet mani ⁇ fold 66.
• the corrugated strips 40 are preferably welded to the housing 48 to form the manifolding.
• the width of corrugated strip 40 introduces a desired flexi ⁇ bility into the heat exchanger unit, as it allows the reduction of stresses in the presence of thermal gradients. It is also possible, but less desirable, to weld rigid manifolding directly to the pleated assemblies, which is not shown in Figure 6. However, this means of attaching the manifolding to the pleated assembly does not provide the flexibility and conse- quent dissipation of thermal stresses possible with the arrangement shown in Figure 6.
• FIG. 7 illustrates an end view of the heat exchanger module 46 used as a recuperator for re ⁇ ceiving hot exhaust gas and compressed air from a gas turbine engine.
• Hot gas input manifolds 56 are at the top and bottom and the hot combustion air output manifold 66 is in the center. Hot gas flows in alternate passages 58 while air to be heated flows in the opposite direction through the intermediate passages 64.
• the housing 48 closes the open ends of the passages 58.
• FIG. 8 A second embodiment of the present invention is diagrammatically shown in Figures 8, 9, and 10.
• Heat exchanger sheet material 72 which has been serrated along the longitudinal edges in the same manner as sheet 10 in Figure 1 and subsequently em ⁇ bossed, is bent between points 68 and 70 by passing it over shaped rollers, which are not shown in Figure 8, prior to pleating to form a sheet which is rippled in cross section (Figure 9).
• This structure provides flexibility to the pleats in the direction 68-70.
• Figure 10 which corresponds to Figure 3 shows the rippled sheet 72 being pleated and compressed into a bent pleated assembly 74.
• the method depicted in Figures 8, 9, and 10 results in increased flexibil ⁇ ity, not only in the pleats themselves, but also in the welded plugs 42 and 44 used to seal alternate flow passages as shown in Figures 5 and 7. Additional flexibility in the direction of sheet width 12 shown in Figure 1 can be introduced in still another embodiment of the present invention.
• the compressed pleated assembly shown at 36 in Figure 3 can be made to assume an arcuate shape or even an *S" shape, (not shown) when viewed in the direction of the crest portions or edges 34, as depicted in Figure 11.
• the sheet 10 can be treated in an al ⁇ ternate method after pleating to enhance fluid flow and flexibility * This is accomplished as shown in Figure 12.
• a pleated and compressed sheet, indi ⁇ cated generally at 76, is passed over a roller 78, which causes the pleats to separate as at 80 while remaining compressed at 82, thus allowing cams, rollers, pawls, or other suitable mechanisms to be introduced into the wide gaps at 80 to spread the pleats at edge 34 to any desired distance.
• roller 78 After passing over roller 78, the pleated and compressed sheet passes over roller 84 where the wide gaps 80 become compressed
• the heat exchanger module 46 may be effectively employed as a recuperator for a gas turbine engine or for other heat exchange applications, as, for example, in steel heat treating or melting furnaces.
• the inlet manifold 62 is connected to a source of cool fluid to be heated while the inlet manifolds 56 are connected to a source of heated fluid.
• the inlet manifolds 56 would be connected to receive hot exhaust gases from the engine while the inlet manifold 62 would be connected to receive compressor discharge air from the engine.
• the cooler discharge air passes through the pleated assemblies 38a and 38b with the counter flowing hot exhaust gas, the air is heated by the heat transfer provided by heat exchange sections 22 and 24.
• the exhaust gas then passes out of the outlet manifolds 60 and is normally vented to the atmosphere while the heated air passes to the outlet manifold 66.
• This outlet manifold is connected to the ⁇ ombustor of the gas turbine engine and proceeds on through the engine in the conventional manner.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

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ID=22154432

Family Applications (1)

Country Status (5)

Cited By (12)

Families Citing this family (10)

Citations (8)

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• 1980
  • 1980-07-07 JP JP81501291A patent/JPS57500945A/ja active Pending
  • 1980-07-07 DE DE8181900865T patent/DE3071178D1/de not_active Expired
  • 1980-07-07 EP EP81900865A patent/EP0055711B1/de not_active Expired
  • 1980-07-07 WO PCT/US1980/000857 patent/WO1982000194A1/en active IP Right Grant
• 1981
  • 1981-03-17 CA CA000373159A patent/CA1140531A/en not_active Expired

Patent Citations (8)

Non-Patent Citations (1)

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