CA1213880A - Heat exchanger unit and method of manufacture - Google Patents
Heat exchanger unit and method of manufactureInfo
- Publication number
- CA1213880A CA1213880A CA000439098A CA439098A CA1213880A CA 1213880 A CA1213880 A CA 1213880A CA 000439098 A CA000439098 A CA 000439098A CA 439098 A CA439098 A CA 439098A CA 1213880 A CA1213880 A CA 1213880A
- Authority
- CA
- Canada
- Prior art keywords
- flange
- heat exchanger
- flanges
- section
- bead
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000000034 method Methods 0.000 title claims description 25
- 238000004519 manufacturing process Methods 0.000 title description 3
- 239000011324 bead Substances 0.000 claims abstract description 42
- 230000001154 acute effect Effects 0.000 claims abstract description 8
- 238000002788 crimping Methods 0.000 claims description 11
- 230000009471 action Effects 0.000 claims description 6
- 238000005304 joining Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 4
- 238000003825 pressing Methods 0.000 claims description 4
- 230000000295 complement effect Effects 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 2
- 230000002093 peripheral effect Effects 0.000 description 12
- 230000015572 biosynthetic process Effects 0.000 description 9
- 230000008569 process Effects 0.000 description 8
- 239000007789 gas Substances 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 6
- 238000001816 cooling Methods 0.000 description 5
- 238000006073 displacement reaction Methods 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- 239000002341 toxic gas Substances 0.000 description 1
Landscapes
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A heat exchanger unit having opposed pan shaped sections with perimeter flanges which are folded one over the other to secure the sections together. The section having the inner flange is formed with a displaced flange portion or bead all along the perimeter flange portions, which bead is elastically displaced by the folded over flange to form a substantially leakproof joint. The edges of the sections formed by the flanges are crimped at spaced apart locations to extend in respective planes coincident with a central longitudinal plane through the heat exchanger and extending at an acute angle with respect to said longitudinal plane to form small triangular shaped areas interconnecting the crimped locations.
A heat exchanger unit having opposed pan shaped sections with perimeter flanges which are folded one over the other to secure the sections together. The section having the inner flange is formed with a displaced flange portion or bead all along the perimeter flange portions, which bead is elastically displaced by the folded over flange to form a substantially leakproof joint. The edges of the sections formed by the flanges are crimped at spaced apart locations to extend in respective planes coincident with a central longitudinal plane through the heat exchanger and extending at an acute angle with respect to said longitudinal plane to form small triangular shaped areas interconnecting the crimped locations.
Description
HEAT EXCHANGER UNIT AND METHOD
OF MAN UFACT U:RE
BACKGROUND O~ THE INVENTION
F~ield of the Invention The present invention pertains to a heat exchanger unit particularly adapted for gas fired hot air furnaces wherein two pan shaped sections are joined together along cooperating flanges w'nich are folded one over the other and crimped tightly to form a substantially leakproof joint.
Background In the development of so-called clamshell type furnace and other hot ~ir generating heat exchanger units, there has been a need to develop a method for joining the opposed pan shaped shell sections which eliminates the requirement to weld the sections to each other to form a leakproof joint, Welding operations are particularly time consuming and expensive to carry out due to labor costs and requirements to maintain the working environment free of toxic gases generated during the welding process . However ! the development of a ~uitable non-welded joint between two sections of a furnace heat exchanger present certain problems in that a joint must be formed which is capable of remaining substantially leakproof or gas tight under the severe thermal stresses encountered by the heat exchanger during the repeated heated and cooling cycles that occur in a hot air heating furnace, for example.
- ~ -On the other hand, under certain operating co-rlditi-,ns it may be desirable to have a seam or ioint between the sections fj~ a shell type heat exchanger which will temporarily yield to excessive pressure within the interior of the heat exchanger to release gas 5 pressure without the heat exchanger undergoing a catastropnic fa~ure itself. Accordingly, it is a primary object of the present invention to provide a clamshell type heat exchanger unit having opposed pan shaped shell sections, each formed with a peripheral flange, which are joined together in an improved manner which doe~; not require any welding or braising processes, and w'nich forms a joint which is substantia]ly leakproof. It is also an object s~f the invention to provide a joint between pan shaped furnace heat exchanger secticns which is operable to temporarily yield to excessive gas pressures and which may be formed using substantially conventional hydraulic or other mechanically actuated press equipmen~ to form a joint wherein a flange on one heat exchanger section is folded over a coopel ating flange on the other heat exchanger section. These objectives have been met by the improved heat exchanger unit and the method for forming a joint between opposed pan shaped or clamshell sections of the heat exchanger unit in accordance with the invention described and claimed herein.
SUMMARY VF THE INVENTION
The present invention provides an improved clamshell heat exchanger unit including opposed pan shapes~ or clamshell type sheet metal sections which are joined together along a peripheral edge by forming each of the sections with flanges which are configured to permit folding one flange over the other and crimping the flanges in such a way as to securely lock the shell sections together to form a substantially gas-tight seal and to prevent relative movement of the sections during cyclical heating and cooling of the heat exchanger.
In accordance with an important aspect of the present invention the flange of one of the sections is formed with an elongated peripheral bead or displaced portion. The cooperating flange on the other shell section is folded over the first flange and pressed against the bead sufficiently to displace it elastically and to sandwich the first flange between the folded flange portions of the other section. The elastic displacement of the bead assures that the J
first or sand~iched flange p-resses tightly against, the c,pposed ~an~-,e portions of the other section to form a su~stantially ga~-tight seal at norrmal operating pressures and temperatures.
Several advantages arise from the ~rmatiorl of the peripheral bead type seal for the heat exchanger unit in accordance with the present invention. The formation of the bead on the one flange causes the peripheral edge of the flange to be bent at an angle with respect to the plane of the flange of the other section so that during the folding and pressing process the edge of the ~1rst flange will forcibly engage the surface of the inner peripheral portion s~f the second flange. The arched portion of the first flange forming the bead is flattened during the folding process and the peripheral edge of the flange is forced into the bottom of the recess formed by the folded over flange to thereby also enhance the seal hetween the flanges.
Another important feature of the improvement of the present invention is that the elastic memory retained by the bead or arched flange portion provides a constant biasing force which tightly presses the inner flange against the opposed portions of the outer and folded flange. Such an arrangement permits the use of pressing or forming equipment wherein the forming die members may be slightly misaligned without causing the formation of an ineffective seal. Moreover, such a joint as been observed to yield under excessive pressure within the heat exchanger to permit pressure release or leakage and then reseal itself when the pressure is reduced.
In accordance with the present invention there has also been developed an improved method of forming a heat exchanger unit having opposed pan shaped or clamshell type sections wherein each section has a flange ~ormed along one or more edges and the flange of one section is folded over a cooperating flange of the other section to join the sections together to form a substantially gas-tight seal. The edges of the heat exchanger unit are crimped along the cooperating folded together flanges at a plurality of edge lengthwise spaced locations in such a way that one set of edge portions extend parallel to a central longituclinally extending dividing plane between the heat exchanger sections and another set of edge portions extend at an acute angle with respect to the dividing plane to thereby create a so-called scissor action on small areas joining the edge po~irJn s in such a way that the clamshell sections are securely locked to,J,ether to prevent undesirable relative movement du-ring the extreme heating and cooling cycles that the heat exchanger undergoes suc'n as when used in a hot air heating furnace. By providing the inner flange ,~Jith a raised peripheral bead that is elastically displaced upon folding the flange of the other section over the inner flange an impr~ ed seal between the flanges is formed and is enhanced by the fu-rther crimping operation to reduce the tendency for the shell sections to move relative to each other under stresses induced by cyclical heating and cooling of the heat exchanger unit. In fact, a somewhat synergistic effect has been realized by the method and apparatus of the present invention wherein the provision of the beaded flange and the folded and crirnped flanges yields a heat exchanger which has superior operating characteristics and is more economical to manufacture than prior art apparatus.
Those skilled in the art will recognize the above-described features and superior aspects of the present invention as well as other advantages thereof upon reading the detailed description which follows in conjunction witll the drawing.
BRIEF DESCRIPTION OF THE DRAWING
Figure 1 is a side elevation view of a heat exchanger unit having edges forrned in accordance with the present invention;
Figure 2 is a partial rear elevation of the heat exchanger unit illustrated in Figure 1;
Figure 3 is a detail section view of the shell sections similar to Figure 4 but showing the flanges of the respective sections after formation of the raised bead or arched portion and before the final folding and crimping of the flanges;
Figure 4 is a detail section view taken along the line 4~4 of Figure 1 and showing the relationship of the flanges after the forming process;
Figure 5 is a detail plan view of a corner of the shell section including the beaded l1ange;
Figure 6 is a detail perspective view of two intersecting flanges of the other shell section before the folding operation;
- ~ -Figure 7 is a detail section view taken alon~ the line 7-7 of Figure 3 and illustrating the blending out of the flange bead; an-~
Figure 8 is a detail perspective vie~N on the sheet ~:/'nich includes Figures 3 and 4 of one of the edges of ~he heat exchanger 5 unit showing the crimped edge portions.
D~SCRIPTION OF THE PREFERRED EMBODI~JlENTS
In the description which follows like parts are marXed throughout the specification and drawings with the same reference numerals, respectively. The drawings are not necessarily to scale and certain features may be exaggerated in scale in order to better illustrate the invention.
Referring particularly to Figures 1 and 2 there is illustrated an air-to-air heat exchanger unit particularly adapted for use in a gas fired hot air furnace, which heat exchanger is generally designated by the numeral 10. The heat exchanger 10 includes opposed clamshell or pan shaped sections 12 and 14 which are joined together to form an enclosed chamber 16, Figures 3 or 4, through which combustion products may flow to heat the outer sur~aces of the shell sections for heat exchange with air flowing over the exterior of the heat exchanger unit. The heat exchanger 10 includes a lower pouch section 18 including an opening 20 for reception of a burner unit, for example, and an upper portion 22 including an exit opening 24 for combustion products.
The heat exchanger unit 10 is generally in accordance with the unit describe~l and claimed in U.S. Patent 4,298,061. The heat exchanger unit 10 is sealed around its perimeter at each of top, bottom and opposed side edges 28, 30, 32 and 34, respectively.
Along each of the aforementioned edges the section 12 is formed with a peripheral nange 36 which, as shown in Figure 3, is initially formed with an upturned outer edge portion 38 when the section 12 itself is lying with its interior recessed portion facing upward. In like manner, the shell section 14 is formed with cooperating perimeter flange portions 40 in such a way that, upon assembly of the shell section 14 over the shell section 12 to form the chamber 16 the flange 40 rests on the flange 36.
As shown in Figure 1, each of the edges 28, 30, 32 and 34 is crimped in final assembly at a plurality of locations 41, and ~f;
therebetween at locations 43 at an acute an~le A ~ FigTlre ~, ~lith respect to a central longitudinal plane 44. The criraping of the aforementioned peripheral edges of the exchanger unit 1~ croa~e3 ~
s~issor action on the small displaced areas of the flanges forme~ by the crimped locations 41 and 43. Figure 8 illustrates, by w~y of example, a portion of the edge 34 showing the crimped locations 41 and 43, and the small triangular shaped areas 42 formed betvJeen the crimped locations which are subject to the scissor action and which extend in planes whieh intersect the planes of the crimped locations 41 and 43.
Yurther in accordance with the present invention, each of the flange portions 40 of the shell section 14 is provided with an elongated raised or arched bead or ridge, generally designated by the numeral 47 in Figures 3 and 4, by displacing a portion of the flange in accordance with a conventional die forming operation, for example.
The formation of the bead 47 is preferably carried out by displacing the outer edge portion of the flange 40 away from the plane 44 and causing the longitudinal edge 49 to lie in a plane forming an acute angle B with respect to the plane 44 as indicated in Figure 3. As shown in Figure 5, the beads 47 extending along the edges 30 and 32, for example, intersect to form a continuous corner ridge 53.
Figure 6 illustrates the complementary corner portions of the flanges 36 formed along the edges 30 and 32 of the shell section 12 which, as shown by way of example, are formed to include a generally V-shaped notch 55 extending from the outer peripheral edge of the ~lange sections 38 approximately three-quarters of the width of that flange section to leave an upstanding flange portion 39 of reduced height.
A notch 55 is also formed at the intersection of the flange portions 38 for the edges 28 and 30, each notch 55 having an included angle of approximately 90 .
Where the flanges 40 terminate at a lateral edge, such as at 81, 83 and 85 in Figure 1, the bead 47 is blended out to the plane 4~1 which is coincident with the flange 40, as shown in Figure 7 by way of example.
In the process of manufacturing the heat exchanger unit 10 the shell sections 12 and 14 are separately -formed by conventional forging equipment to form the recessed portions of the sections and the respective integral flanges 36-38 and 40. The for~n&~ proce3~
may include the formation of the bead 47 along eac'n flange 40 OL ~ile section 14 and folding of the flange portions 3~ in the ~ltrection indicated to the position shown in Figure 3 during the formation of the sections 12. The shell section 14 is then nested within t'ne shell section 12, as indicated in Figure 3, with the shell section 12 in a die apparatus which is capable of folding the flange port,ion 38 over the bead 47 and the flange 40 to the position illustrated in ~ re 4.
The process of folding the flange portion 38 over to sandwich the 1~ flange 40 between the opposed flange portions 36 and 38 forms a substantially gas-tight seal around the edges of the heat exchanger unit, thanks to the displacement of the 'oead 47 which is reduced in height by approximately 90%, as illustrated, when comparing the remaining portion of the bead as shown in Figtlre 4. The folding process results in the edge 49 of the flange 40 being forcibly engaged with the surface of the flange 36 near its juncture with the flange portion 38 to dig into the material of the flange .36. Any burrs or flash left on the edge 4 9 as a result of the formation of the shell section lg is of assistance in forming a gas-tight seal between the shell sections at the small space or gap 59, Figure 4, remaining between the outer edge 49 and the base of a recess formed between the opposed flange portions 36 and 38 which is filled by the -flange 40. The blended out portions at the lateral edges 81, 83 and ~5, as shown by way of example in Figure 7, assures that no gap between the ~langes 40 and 36-38 remain for possible leakage of fluid at the ends of these edges and along a small passage which may be formed by a residual gap 61 as shown in Figure 4.
As described previously the formation of the displaced ridge portion or bead 47 along the flanges 40 provides the advantage that upon folding the flange portion 38 downward into the pressed position shown in Ftgure 4 the outer edge 49 of the flange 40 is forced into the bottom of the recess leaving only the small gap 59 or no gap at all, thereby forming a better edge seal for the seam between the contiguous surfaces of the flanges 40 and 36. Moreover, the formation of the bead 47 and the displacement thereof into the position shown in Figure 4 is such as to leave enough elastic memory in the bead portion which tends to cause the upper surface 71 of the bead to press against the flange portion 38 while the edge 4~ terids ,o press into the adjacent surface of the flange 36 thereby enhanf~rlg the seal along the seam between the flanges of the shell sections 1 and 14.
The corners of the flanges 36 are for~ed generally in accordance with the description of the corners of the flanges in U.S.
Patent 4,298,061. However, as shown in ~igure 6 the reduced portion 39 of the flange portion 38 is of sufficient height which, Ylrhen folded over, will engage and displace the corner portion of the bead 47 in substantially the same manner that the lineal portions of the bead are displaced. 'rhe opposed edges 73 and 75 of the notch 5~
are dimensioned to lie substantially adjacent each other in the folded position. Accordingly, any excess flange material is displaced into any unoccupied crevices between the edges 73 and 75 or any area that the folding die will accommodate.
Subsequent to the folding of the flange portions 38 and displacement of the beads 47, each of the edges 28, 30, 32 and 3~ are crimped to form a substantially leakproof or gas-tight seal along the peripheral edges of the heat exchanger unit which will prevent undesirable movement between the shell sections during the alternate heating and cooling cycles encountered by heat exchangers used in gas fired hot air furnaces for residential and commercial applications, for example. ~3a~h of the edges 28, 30, 32 and 34 is crimped parallel to the central longitudinally extending plane 44 at a plurality of locations 41, and therebetween at locations 43 at the acute angle A
with respect to said plane to thereby create the scissor action on the small areas 42 along the perimeter between these locations. Such action securely locks the two shell sections 12 and 14 together.
The heat exchanger 10 may be manufactured of conventional material such as 16 to 20 gauge ( U . S . Std . ) sheet steel . The height of the bead 47 from the plane 44 to the inner sur~ace 77 of the bead, ~igure 3, may be on the order of .0625 inches for an ideal flange thickness of . 0335 inches .
Conventional press forming or crimping equipment, which has been modified to accommodate the speci-fic configuration of the heat exchanger unit 10, may be used to fold the flange portions 38 and perform the crimping operation to form -the crimped locations 41 ,.5""5~ ;J
_g_ and 43 described. Preferably, the ec~uipment is adapted to per~orm the flange folding and crimping operations in a single continllou3 step. The heat exchanger unit 10 is typically provided in a plurality of units secured to a heat exchanger plate assembly.
Those skilled in the art will recognize that t'ne invention described and claimed herein may be subject to val ious alteration3 and modifications of the structure and the method without departing from the scope and spirit of the invention as defined in the appended claims.
OF MAN UFACT U:RE
BACKGROUND O~ THE INVENTION
F~ield of the Invention The present invention pertains to a heat exchanger unit particularly adapted for gas fired hot air furnaces wherein two pan shaped sections are joined together along cooperating flanges w'nich are folded one over the other and crimped tightly to form a substantially leakproof joint.
Background In the development of so-called clamshell type furnace and other hot ~ir generating heat exchanger units, there has been a need to develop a method for joining the opposed pan shaped shell sections which eliminates the requirement to weld the sections to each other to form a leakproof joint, Welding operations are particularly time consuming and expensive to carry out due to labor costs and requirements to maintain the working environment free of toxic gases generated during the welding process . However ! the development of a ~uitable non-welded joint between two sections of a furnace heat exchanger present certain problems in that a joint must be formed which is capable of remaining substantially leakproof or gas tight under the severe thermal stresses encountered by the heat exchanger during the repeated heated and cooling cycles that occur in a hot air heating furnace, for example.
- ~ -On the other hand, under certain operating co-rlditi-,ns it may be desirable to have a seam or ioint between the sections fj~ a shell type heat exchanger which will temporarily yield to excessive pressure within the interior of the heat exchanger to release gas 5 pressure without the heat exchanger undergoing a catastropnic fa~ure itself. Accordingly, it is a primary object of the present invention to provide a clamshell type heat exchanger unit having opposed pan shaped shell sections, each formed with a peripheral flange, which are joined together in an improved manner which doe~; not require any welding or braising processes, and w'nich forms a joint which is substantia]ly leakproof. It is also an object s~f the invention to provide a joint between pan shaped furnace heat exchanger secticns which is operable to temporarily yield to excessive gas pressures and which may be formed using substantially conventional hydraulic or other mechanically actuated press equipmen~ to form a joint wherein a flange on one heat exchanger section is folded over a coopel ating flange on the other heat exchanger section. These objectives have been met by the improved heat exchanger unit and the method for forming a joint between opposed pan shaped or clamshell sections of the heat exchanger unit in accordance with the invention described and claimed herein.
SUMMARY VF THE INVENTION
The present invention provides an improved clamshell heat exchanger unit including opposed pan shapes~ or clamshell type sheet metal sections which are joined together along a peripheral edge by forming each of the sections with flanges which are configured to permit folding one flange over the other and crimping the flanges in such a way as to securely lock the shell sections together to form a substantially gas-tight seal and to prevent relative movement of the sections during cyclical heating and cooling of the heat exchanger.
In accordance with an important aspect of the present invention the flange of one of the sections is formed with an elongated peripheral bead or displaced portion. The cooperating flange on the other shell section is folded over the first flange and pressed against the bead sufficiently to displace it elastically and to sandwich the first flange between the folded flange portions of the other section. The elastic displacement of the bead assures that the J
first or sand~iched flange p-resses tightly against, the c,pposed ~an~-,e portions of the other section to form a su~stantially ga~-tight seal at norrmal operating pressures and temperatures.
Several advantages arise from the ~rmatiorl of the peripheral bead type seal for the heat exchanger unit in accordance with the present invention. The formation of the bead on the one flange causes the peripheral edge of the flange to be bent at an angle with respect to the plane of the flange of the other section so that during the folding and pressing process the edge of the ~1rst flange will forcibly engage the surface of the inner peripheral portion s~f the second flange. The arched portion of the first flange forming the bead is flattened during the folding process and the peripheral edge of the flange is forced into the bottom of the recess formed by the folded over flange to thereby also enhance the seal hetween the flanges.
Another important feature of the improvement of the present invention is that the elastic memory retained by the bead or arched flange portion provides a constant biasing force which tightly presses the inner flange against the opposed portions of the outer and folded flange. Such an arrangement permits the use of pressing or forming equipment wherein the forming die members may be slightly misaligned without causing the formation of an ineffective seal. Moreover, such a joint as been observed to yield under excessive pressure within the heat exchanger to permit pressure release or leakage and then reseal itself when the pressure is reduced.
In accordance with the present invention there has also been developed an improved method of forming a heat exchanger unit having opposed pan shaped or clamshell type sections wherein each section has a flange ~ormed along one or more edges and the flange of one section is folded over a cooperating flange of the other section to join the sections together to form a substantially gas-tight seal. The edges of the heat exchanger unit are crimped along the cooperating folded together flanges at a plurality of edge lengthwise spaced locations in such a way that one set of edge portions extend parallel to a central longituclinally extending dividing plane between the heat exchanger sections and another set of edge portions extend at an acute angle with respect to the dividing plane to thereby create a so-called scissor action on small areas joining the edge po~irJn s in such a way that the clamshell sections are securely locked to,J,ether to prevent undesirable relative movement du-ring the extreme heating and cooling cycles that the heat exchanger undergoes suc'n as when used in a hot air heating furnace. By providing the inner flange ,~Jith a raised peripheral bead that is elastically displaced upon folding the flange of the other section over the inner flange an impr~ ed seal between the flanges is formed and is enhanced by the fu-rther crimping operation to reduce the tendency for the shell sections to move relative to each other under stresses induced by cyclical heating and cooling of the heat exchanger unit. In fact, a somewhat synergistic effect has been realized by the method and apparatus of the present invention wherein the provision of the beaded flange and the folded and crirnped flanges yields a heat exchanger which has superior operating characteristics and is more economical to manufacture than prior art apparatus.
Those skilled in the art will recognize the above-described features and superior aspects of the present invention as well as other advantages thereof upon reading the detailed description which follows in conjunction witll the drawing.
BRIEF DESCRIPTION OF THE DRAWING
Figure 1 is a side elevation view of a heat exchanger unit having edges forrned in accordance with the present invention;
Figure 2 is a partial rear elevation of the heat exchanger unit illustrated in Figure 1;
Figure 3 is a detail section view of the shell sections similar to Figure 4 but showing the flanges of the respective sections after formation of the raised bead or arched portion and before the final folding and crimping of the flanges;
Figure 4 is a detail section view taken along the line 4~4 of Figure 1 and showing the relationship of the flanges after the forming process;
Figure 5 is a detail plan view of a corner of the shell section including the beaded l1ange;
Figure 6 is a detail perspective view of two intersecting flanges of the other shell section before the folding operation;
- ~ -Figure 7 is a detail section view taken alon~ the line 7-7 of Figure 3 and illustrating the blending out of the flange bead; an-~
Figure 8 is a detail perspective vie~N on the sheet ~:/'nich includes Figures 3 and 4 of one of the edges of ~he heat exchanger 5 unit showing the crimped edge portions.
D~SCRIPTION OF THE PREFERRED EMBODI~JlENTS
In the description which follows like parts are marXed throughout the specification and drawings with the same reference numerals, respectively. The drawings are not necessarily to scale and certain features may be exaggerated in scale in order to better illustrate the invention.
Referring particularly to Figures 1 and 2 there is illustrated an air-to-air heat exchanger unit particularly adapted for use in a gas fired hot air furnace, which heat exchanger is generally designated by the numeral 10. The heat exchanger 10 includes opposed clamshell or pan shaped sections 12 and 14 which are joined together to form an enclosed chamber 16, Figures 3 or 4, through which combustion products may flow to heat the outer sur~aces of the shell sections for heat exchange with air flowing over the exterior of the heat exchanger unit. The heat exchanger 10 includes a lower pouch section 18 including an opening 20 for reception of a burner unit, for example, and an upper portion 22 including an exit opening 24 for combustion products.
The heat exchanger unit 10 is generally in accordance with the unit describe~l and claimed in U.S. Patent 4,298,061. The heat exchanger unit 10 is sealed around its perimeter at each of top, bottom and opposed side edges 28, 30, 32 and 34, respectively.
Along each of the aforementioned edges the section 12 is formed with a peripheral nange 36 which, as shown in Figure 3, is initially formed with an upturned outer edge portion 38 when the section 12 itself is lying with its interior recessed portion facing upward. In like manner, the shell section 14 is formed with cooperating perimeter flange portions 40 in such a way that, upon assembly of the shell section 14 over the shell section 12 to form the chamber 16 the flange 40 rests on the flange 36.
As shown in Figure 1, each of the edges 28, 30, 32 and 34 is crimped in final assembly at a plurality of locations 41, and ~f;
therebetween at locations 43 at an acute an~le A ~ FigTlre ~, ~lith respect to a central longitudinal plane 44. The criraping of the aforementioned peripheral edges of the exchanger unit 1~ croa~e3 ~
s~issor action on the small displaced areas of the flanges forme~ by the crimped locations 41 and 43. Figure 8 illustrates, by w~y of example, a portion of the edge 34 showing the crimped locations 41 and 43, and the small triangular shaped areas 42 formed betvJeen the crimped locations which are subject to the scissor action and which extend in planes whieh intersect the planes of the crimped locations 41 and 43.
Yurther in accordance with the present invention, each of the flange portions 40 of the shell section 14 is provided with an elongated raised or arched bead or ridge, generally designated by the numeral 47 in Figures 3 and 4, by displacing a portion of the flange in accordance with a conventional die forming operation, for example.
The formation of the bead 47 is preferably carried out by displacing the outer edge portion of the flange 40 away from the plane 44 and causing the longitudinal edge 49 to lie in a plane forming an acute angle B with respect to the plane 44 as indicated in Figure 3. As shown in Figure 5, the beads 47 extending along the edges 30 and 32, for example, intersect to form a continuous corner ridge 53.
Figure 6 illustrates the complementary corner portions of the flanges 36 formed along the edges 30 and 32 of the shell section 12 which, as shown by way of example, are formed to include a generally V-shaped notch 55 extending from the outer peripheral edge of the ~lange sections 38 approximately three-quarters of the width of that flange section to leave an upstanding flange portion 39 of reduced height.
A notch 55 is also formed at the intersection of the flange portions 38 for the edges 28 and 30, each notch 55 having an included angle of approximately 90 .
Where the flanges 40 terminate at a lateral edge, such as at 81, 83 and 85 in Figure 1, the bead 47 is blended out to the plane 4~1 which is coincident with the flange 40, as shown in Figure 7 by way of example.
In the process of manufacturing the heat exchanger unit 10 the shell sections 12 and 14 are separately -formed by conventional forging equipment to form the recessed portions of the sections and the respective integral flanges 36-38 and 40. The for~n&~ proce3~
may include the formation of the bead 47 along eac'n flange 40 OL ~ile section 14 and folding of the flange portions 3~ in the ~ltrection indicated to the position shown in Figure 3 during the formation of the sections 12. The shell section 14 is then nested within t'ne shell section 12, as indicated in Figure 3, with the shell section 12 in a die apparatus which is capable of folding the flange port,ion 38 over the bead 47 and the flange 40 to the position illustrated in ~ re 4.
The process of folding the flange portion 38 over to sandwich the 1~ flange 40 between the opposed flange portions 36 and 38 forms a substantially gas-tight seal around the edges of the heat exchanger unit, thanks to the displacement of the 'oead 47 which is reduced in height by approximately 90%, as illustrated, when comparing the remaining portion of the bead as shown in Figtlre 4. The folding process results in the edge 49 of the flange 40 being forcibly engaged with the surface of the flange 36 near its juncture with the flange portion 38 to dig into the material of the flange .36. Any burrs or flash left on the edge 4 9 as a result of the formation of the shell section lg is of assistance in forming a gas-tight seal between the shell sections at the small space or gap 59, Figure 4, remaining between the outer edge 49 and the base of a recess formed between the opposed flange portions 36 and 38 which is filled by the -flange 40. The blended out portions at the lateral edges 81, 83 and ~5, as shown by way of example in Figure 7, assures that no gap between the ~langes 40 and 36-38 remain for possible leakage of fluid at the ends of these edges and along a small passage which may be formed by a residual gap 61 as shown in Figure 4.
As described previously the formation of the displaced ridge portion or bead 47 along the flanges 40 provides the advantage that upon folding the flange portion 38 downward into the pressed position shown in Ftgure 4 the outer edge 49 of the flange 40 is forced into the bottom of the recess leaving only the small gap 59 or no gap at all, thereby forming a better edge seal for the seam between the contiguous surfaces of the flanges 40 and 36. Moreover, the formation of the bead 47 and the displacement thereof into the position shown in Figure 4 is such as to leave enough elastic memory in the bead portion which tends to cause the upper surface 71 of the bead to press against the flange portion 38 while the edge 4~ terids ,o press into the adjacent surface of the flange 36 thereby enhanf~rlg the seal along the seam between the flanges of the shell sections 1 and 14.
The corners of the flanges 36 are for~ed generally in accordance with the description of the corners of the flanges in U.S.
Patent 4,298,061. However, as shown in ~igure 6 the reduced portion 39 of the flange portion 38 is of sufficient height which, Ylrhen folded over, will engage and displace the corner portion of the bead 47 in substantially the same manner that the lineal portions of the bead are displaced. 'rhe opposed edges 73 and 75 of the notch 5~
are dimensioned to lie substantially adjacent each other in the folded position. Accordingly, any excess flange material is displaced into any unoccupied crevices between the edges 73 and 75 or any area that the folding die will accommodate.
Subsequent to the folding of the flange portions 38 and displacement of the beads 47, each of the edges 28, 30, 32 and 3~ are crimped to form a substantially leakproof or gas-tight seal along the peripheral edges of the heat exchanger unit which will prevent undesirable movement between the shell sections during the alternate heating and cooling cycles encountered by heat exchangers used in gas fired hot air furnaces for residential and commercial applications, for example. ~3a~h of the edges 28, 30, 32 and 34 is crimped parallel to the central longitudinally extending plane 44 at a plurality of locations 41, and therebetween at locations 43 at the acute angle A
with respect to said plane to thereby create the scissor action on the small areas 42 along the perimeter between these locations. Such action securely locks the two shell sections 12 and 14 together.
The heat exchanger 10 may be manufactured of conventional material such as 16 to 20 gauge ( U . S . Std . ) sheet steel . The height of the bead 47 from the plane 44 to the inner sur~ace 77 of the bead, ~igure 3, may be on the order of .0625 inches for an ideal flange thickness of . 0335 inches .
Conventional press forming or crimping equipment, which has been modified to accommodate the speci-fic configuration of the heat exchanger unit 10, may be used to fold the flange portions 38 and perform the crimping operation to form -the crimped locations 41 ,.5""5~ ;J
_g_ and 43 described. Preferably, the ec~uipment is adapted to per~orm the flange folding and crimping operations in a single continllou3 step. The heat exchanger unit 10 is typically provided in a plurality of units secured to a heat exchanger plate assembly.
Those skilled in the art will recognize that t'ne invention described and claimed herein may be subject to val ious alteration3 and modifications of the structure and the method without departing from the scope and spirit of the invention as defined in the appended claims.
Claims (18)
1. A heat exchanger unit for a hot air furnace or the like, having a pair of opposed shell sections each having a flange formed along at least one edge complementary to the adjacent edge of the other section, said flanges being adapted to be engaged by folding at least an outer portion of one of the flanges over the other flange, said other flange having a portion forming a bead which is engaged by said folded over portion of said one flange by pressing said folded over portion of said one flange against said other flange to form a substantially leakproof joint.
2. The heat exchanger set forth in Claim 1 wherein:
an outer edge portion of said other flange is formed to extend at an angle with respect to a longitudinal plane through said heat exchanger unit.
an outer edge portion of said other flange is formed to extend at an angle with respect to a longitudinal plane through said heat exchanger unit.
3. The heat exchanger set forth in Claim 2 wherein:
said bead is formed by displacing a portion of said other flange out of a plane coincident with said other flange and with said longitudinal plane.
said bead is formed by displacing a portion of said other flange out of a plane coincident with said other flange and with said longitudinal plane.
4. The heat exchanger set forth in Claims 1 or 3 wherein:
said bead is elastically displaced by said folded over portion of said one flange whereby said bead and the outer edge of said other flange are biased into forcible engagement with opposed portions of said one flange, respectively.
said bead is elastically displaced by said folded over portion of said one flange whereby said bead and the outer edge of said other flange are biased into forcible engagement with opposed portions of said one flange, respectively.
5. The heat exchanger set forth in Claims 1 or 3 wherein:
said bead is elastically displaced by said folded over portion of said one flange whereby said bead and the outer edge of said other flange are biased into forcible engagement with opposed portions of said one flange, respectively, and wherein said other flange is displaced by said folded over portion to substantially fill a recess formed between opposed portions of said one flange when said one flange is folded over said other flange.
said bead is elastically displaced by said folded over portion of said one flange whereby said bead and the outer edge of said other flange are biased into forcible engagement with opposed portions of said one flange, respectively, and wherein said other flange is displaced by said folded over portion to substantially fill a recess formed between opposed portions of said one flange when said one flange is folded over said other flange.
6. The heat exchanger set forth in Claim 1 wherein:
said sections each include adjacent intersecting flanges forming a corner edge of said heat exchanger unit, said bead being formed as a continuous portion along the intersecting flanges of one section and the complementary intersecting flanges of the other section being formed with a notch at said corner and an outer flange portion of reduced width and formed such that said outer flange portions may be folded over and engaged with the entire length of said bead.
said sections each include adjacent intersecting flanges forming a corner edge of said heat exchanger unit, said bead being formed as a continuous portion along the intersecting flanges of one section and the complementary intersecting flanges of the other section being formed with a notch at said corner and an outer flange portion of reduced width and formed such that said outer flange portions may be folded over and engaged with the entire length of said bead.
7. The heat exchanger set forth in Claim 3 wherein:
said bead is blended out to said longitudinal plane and toward a transverse end edge of said other flange.
said bead is blended out to said longitudinal plane and toward a transverse end edge of said other flange.
8. The heat exchanger set forth in Claim 1 or 3 wherein:
said flanges are crimped together at a plurality of locations where they extend in one direction with respect to a longitudinal plane through said heat exchanger, and said flanges are crimped between said locations where they extend in another direction with respect to said longitudinal plane.
said flanges are crimped together at a plurality of locations where they extend in one direction with respect to a longitudinal plane through said heat exchanger, and said flanges are crimped between said locations where they extend in another direction with respect to said longitudinal plane.
9. The heat exchanger unit set forth in Claims 1 or 3 wherein:
said flanges are crimped together at a plurality of locations where they extend in one direction with respect to a longitudinal plane through said heat exchanger, and said flanges are crimped between said locations where they extend in another direction with respect to said longitudinal plane;
and wherein said crimped flanges at said plurality of locations extend substantially parallel to said longitudinal plane exchanger, and said crimped flanges between said locations extend at an acute angle with respect to said longitudinal plane.
said flanges are crimped together at a plurality of locations where they extend in one direction with respect to a longitudinal plane through said heat exchanger, and said flanges are crimped between said locations where they extend in another direction with respect to said longitudinal plane;
and wherein said crimped flanges at said plurality of locations extend substantially parallel to said longitudinal plane exchanger, and said crimped flanges between said locations extend at an acute angle with respect to said longitudinal plane.
10. A method of joining opposed sheet metal sections of a heat exchanger unit along an edge thereof wherein one of said sections is provided with a flange adapted to be joined to a cooperating flange on the other section, said flange on said other section being of sufficient width to permit folding said flange of said other section over said flange of said one section, said method comprising the steps of:
placing said sections opposite each other with said flanges aligned;
folding a portion of said flange of said other section over said flange of said one section; and crimping said flanges together at a plurality of first locations after folding said flange of said other section over said flange of said one section and causing said flanges at said first locations to extend in one direction with respect to a longitudinally extending plane through said heat exchanger, and crimping said flanges together at second locations between said first locations and causing said flanges at said second locations to extend in another direction with respect to said longitudinally extending plane to create a scissor action between the crimped flange portions extending in the different directions to thereby securely clamp and seal said heat exchanger along said edge.
placing said sections opposite each other with said flanges aligned;
folding a portion of said flange of said other section over said flange of said one section; and crimping said flanges together at a plurality of first locations after folding said flange of said other section over said flange of said one section and causing said flanges at said first locations to extend in one direction with respect to a longitudinally extending plane through said heat exchanger, and crimping said flanges together at second locations between said first locations and causing said flanges at said second locations to extend in another direction with respect to said longitudinally extending plane to create a scissor action between the crimped flange portions extending in the different directions to thereby securely clamp and seal said heat exchanger along said edge.
11. The method set forth in Claim 10 including the steps of:
forming a generally elongated bead on the flange of one of said sections extending along said edge; and pressing said flange of the other of said sections against said bead sufficiently to displace said bead to form a seal between said flanges.
forming a generally elongated bead on the flange of one of said sections extending along said edge; and pressing said flange of the other of said sections against said bead sufficiently to displace said bead to form a seal between said flanges.
12. The method set forth in Claim 11 wherein:
the step of forming said bead includes displacing a portion of said flange of said one section away from a plane coincident with said flange of said one section to form a ridge which is elastically deflectable by said flange portion of said other section when pressed by said flange portion of said other section.
the step of forming said bead includes displacing a portion of said flange of said one section away from a plane coincident with said flange of said one section to form a ridge which is elastically deflectable by said flange portion of said other section when pressed by said flange portion of said other section.
13. The method set forth in Claim 12 wherein:
said step of forming said bead includes displacing an outer edge portion of said flange of said one section to lie in a plane forming an acute angle with said plane coincident with said flange of said one section.
said step of forming said bead includes displacing an outer edge portion of said flange of said one section to lie in a plane forming an acute angle with said plane coincident with said flange of said one section.
14. The method set forth in Claim 12 wherein:
said displaced portion of said flange of said one section is tapered toward said plane coincident with said flange of said one section at a lateral edge of said flange of said one section.
said displaced portion of said flange of said one section is tapered toward said plane coincident with said flange of said one section at a lateral edge of said flange of said one section.
15. The method set forth in Claims 10 or 14 wherein:
said heat exchanger is provided with cooperating flanges on top, bottom and opposed side edges of said sections, and the steps of folding and crimping are each performed simultaneously along said top, bottom and opposed side edges.
said heat exchanger is provided with cooperating flanges on top, bottom and opposed side edges of said sections, and the steps of folding and crimping are each performed simultaneously along said top, bottom and opposed side edges.
16. The method set forth in Claims 10 or 14 wherein:
said heat exchanger is provided with cooperating flanges on top, bottom and opposed side edges of said sections, and the steps of folding and crimping are each performed simultaneously along said top, bottom and opposed side edges;
and wherein the folded flanges are caused to meet along mitered edges at corners of the heat exchanger and flange material is squeezed between said edges to form a leakproof corner joint.
said heat exchanger is provided with cooperating flanges on top, bottom and opposed side edges of said sections, and the steps of folding and crimping are each performed simultaneously along said top, bottom and opposed side edges;
and wherein the folded flanges are caused to meet along mitered edges at corners of the heat exchanger and flange material is squeezed between said edges to form a leakproof corner joint.
17. The method set forth in Claim 10 wherein:
the steps of crimping said flanges together at said first and second locations includes the step of forming triangular shaped areas joining said first and second locations.
the steps of crimping said flanges together at said first and second locations includes the step of forming triangular shaped areas joining said first and second locations.
18. The method set forth in Claim 10 wherein:
said flanges at said first locations extend in planes parallel to a central longitudinal plane through said heat exchanger, and said flanges at said second locations extend in a plane forming an acute angle with said central longitudinal plane.
said flanges at said first locations extend in planes parallel to a central longitudinal plane through said heat exchanger, and said flanges at said second locations extend in a plane forming an acute angle with said central longitudinal plane.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000439098A CA1213880A (en) | 1983-10-17 | 1983-10-17 | Heat exchanger unit and method of manufacture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000439098A CA1213880A (en) | 1983-10-17 | 1983-10-17 | Heat exchanger unit and method of manufacture |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1213880A true CA1213880A (en) | 1986-11-12 |
Family
ID=4126287
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000439098A Expired CA1213880A (en) | 1983-10-17 | 1983-10-17 | Heat exchanger unit and method of manufacture |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1213880A (en) |
-
1983
- 1983-10-17 CA CA000439098A patent/CA1213880A/en not_active Expired
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