CA1313184C - Heat exchanger manufacturing method and apparatus - Google Patents
Heat exchanger manufacturing method and apparatusInfo
- Publication number
- CA1313184C CA1313184C CA000594944A CA594944A CA1313184C CA 1313184 C CA1313184 C CA 1313184C CA 000594944 A CA000594944 A CA 000594944A CA 594944 A CA594944 A CA 594944A CA 1313184 C CA1313184 C CA 1313184C
- Authority
- CA
- Canada
- Prior art keywords
- tube
- tubes
- open end
- header
- heat exchange
- 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 - Lifetime
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D53/00—Making other particular articles
- B21D53/02—Making other particular articles heat exchangers or parts thereof, e.g. radiators, condensers fins, headers
- B21D53/08—Making other particular articles heat exchangers or parts thereof, e.g. radiators, condensers fins, headers of both metal tubes and sheet metal
- B21D53/085—Making other particular articles heat exchangers or parts thereof, e.g. radiators, condensers fins, headers of both metal tubes and sheet metal with fins places on zig-zag tubes or parallel tubes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
- F28F9/02—Header boxes; End plates
- F28F9/04—Arrangements for sealing elements into header boxes or end plates
- F28F9/16—Arrangements for sealing elements into header boxes or end plates by permanent joints, e.g. by rolling
- F28F9/162—Arrangements for sealing elements into header boxes or end plates by permanent joints, e.g. by rolling by using bonding or sealing substances, e.g. adhesives
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
- F28F9/02—Header boxes; End plates
- F28F9/04—Arrangements for sealing elements into header boxes or end plates
- F28F9/16—Arrangements for sealing elements into header boxes or end plates by permanent joints, e.g. by rolling
- F28F9/18—Arrangements for sealing elements into header boxes or end plates by permanent joints, e.g. by rolling by welding
- F28F9/182—Arrangements for sealing elements into header boxes or end plates by permanent joints, e.g. by rolling by welding the heat-exchange conduits having ends with a particular shape, e.g. deformed; the heat-exchange conduits or end plates having supplementary joining means, e.g. abutments
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
ABSTRACT
A heat exchanger and heat exchange tubes therefor are disclosed as well as a method of making same, wherein locating bulges are formed in the distal end portions of the heat exchange tubes to locate and retain the heat exchanger headers in position during assembly. The bulges are formed by supporting the heat exchange tubes along their length, such as with a plurality of stacked heat exchange fins through which the tubes pass, and injecting high pressure fluid into the ends of the tubes. The tubes are inserted into the headers and the bulges engage the headers to maintain the spacing therebetween during assembly.
A heat exchanger and heat exchange tubes therefor are disclosed as well as a method of making same, wherein locating bulges are formed in the distal end portions of the heat exchange tubes to locate and retain the heat exchanger headers in position during assembly. The bulges are formed by supporting the heat exchange tubes along their length, such as with a plurality of stacked heat exchange fins through which the tubes pass, and injecting high pressure fluid into the ends of the tubes. The tubes are inserted into the headers and the bulges engage the headers to maintain the spacing therebetween during assembly.
Description
- 2 - 13131~4 This invention relates to heat excllanclers, and in particular to heat exchange tubes used therein.
In the past, heat exchan~ers have heen made consisting of a plurality o discreet heat exchancle tuhes mounted in and communicating with common headers. Such heat exchangers typically have a plura]ity of stacked, transverse, heat transfer fins connected to the tubes, or serpentine heat transfer Eins located hetween and parallel to the tubes. These heat exchangers are often made of brass or tinned steel and the mating surfaces are soldered to produce rigid, leak-proof joints.
A difficulty with the prior art methods of construction is that thermal expansion and contraction during assembly makes it difficult to maintain dimensional tolerances and it often causes leak problems due to poorly formed solder joints. In an attempt to overcome such difficulties, efEorts have heen made to deEorln mating components to mechanically lock or bond them togetller.
However, it is not always possible practically to mechanically lock all of the joints necessary to overcome these difficulties.
Another problem with the prior art construction methods is that heat exchangers are often made from one or more subassemblies which are completed hefore Einal t313184 assembly. If the subassemblies are soldered together and soldering is used in the final assembly, the latter soldering operation can disrupt or dislocate the components of the subassemblies, again playing havoc with the dimensional tolerances of the heat exchan(~ers.
In the present invention, locatin~ bulges are formed in the heat exchange tubes to locate and retain the various components in position durin~ assembly.
Accordin~ to one aspect of the invention, there is provided a method of manufacturing a heat exchange tube for use in a heat exchanger. The method comprises the steps of providing a heat exchange tube having an open end portion and supporting the tube adjacent to the open end portion to prevent lateral expansion of the tube where supported. The distal end of the open end portion of the tube is gripped, and high pressure fluid is injected into the tube to produce a locating bulge in the open end portion spaced ~rom the gripped dista] end.
According to another aspect o the invention, there is provided a method of producing a tube to header joint in a heat exchanger comprising the steps of providing at least one heat exchange tube having an open end portion, providing a header having means defining an opening adapted to accommodate the tube open end portion, and supporting the tube adjacent to the open end portion to prevent lateral expansion of the tube where supported. The distal end of the open end portion of the tube i9 gripped and high pressure fluid is injected into the tube to produce a locating bulge in the open end portion spaced from the gripped distal end. The tube is inserted into the header opening so that the means defining the header opening engages the tube locating bulge, and the joint between the header and the tube is sealed.
According to yet another aspect of the invention, a method of manufacturing a heat exchanger is provided comprising the steps of providing a plurality of parallel heat exchange tubes each having at least one open end portion, providing a header having means defining a plurality of openings adapted to accommodate the tube open end portions, and supporting the tubes adjacent to the open end portions to prevent lateral expansion of the tubes where supported. The distal ends of the open end portions of the plurality of tubes are gripped and high pressure fluid is injected into the tubes to produce locating bulges in the open end portions spaced from the gripped distal ; ends. The tubes are mounted in the header, so that the means defining the header openings engages the tube .
_ 5 - ~313184 locating bulges, and the joints between the header and the tubes are sealed.
According to yet another aspect Oe the invention there is provided a heat exchanger comprising a plurality of parallel heat exchange tubes, each tube having a open end portion. A header is mounted on an communicates with the open end portions, and each tube has a lateral locating bulge adjacent to the header and spacec3 ~rc~m the end of the tube for locating and retaining the header in position.
According to yet another aspect of the invention, there is provided apparatus ~or manufacturing heat exchange tubes for a heat exchanger having a plurality of heat exchange tubes each having an open end communicating with a common header. The apparatus comprises means ~or supporting and preventing lateral expansion of the heat exchange tubes at a location spaced from the ends of the tubes. A fixture is provided for engagin~ the open ends of the tubes prior to assembly with the header, the fixture having means for injecting high pressure fluid into the tubes to produce locating bulges adjacent to and spaced from the ends of the tubes, so that upon assembly of the heat exchanger the locating bulges engage and locate the header in position.
` - 6 - 1313184 According to yet another aspect of the invention there is provided apparatus for manuEacturing a heat exchanger having an assembly o a plurality oE heat exchange tubes mounted in a common header, tlle tuhes having locating bulges formed therein engaging the header. The apparatus comprises a jig for holdin~ the tube and header assembly and means for biasing the header into engagement with the tube locating bulges, so that the tuhe and header assembly can thermally expand and contract during final assembly.
Perferred embodiments of the invention will now be described, by way of example, with reEerence to the accompanying drawings, in which:
Figure 1 is a perspective view, partly exploded and partly broken away, of a preferred embodiment Eor a heat exchanger made according to the present inventi.on;
Figure 2 is a vertical sectional view taken along lines 2-2 of Figure 1 showing part of the assemhled heat exchanger of Figure l;
Figure 3 is a vertical sectional view oE a portion of the apparatus used to form bulges in the ends of the heat exchange tubes shown in Fi~ure 2;
: ' :' ' ~ 7 ~ 1313184 Figure 4 is an elevational dia(lralncltic view oE
the apparatus used in the final assembly o~ the heat exchanger of Figure l;
Figure 5 is a p~erspec~ive view sirnilar to Fiqure 1 but showing another embodirnent Oe a heat exchan(~er made according to the present invention, but having serpentine heat exchange fins; and Figure 6 is an elevational view of a portion oE
the heat exchan~er oE Fi~ure 5 indicate(l by arrow fi in Figure 5.
Referring first to Fi~ure l, a heat exchanger made according to the present invention is generally indicated by reference numeral 10. Heat exchan~er 10 includes a plurality of heat exchan~e tuhes 12 and a pair of opposed headers 14 mounted on and enga~ing the ends of tubes 12. A plurality of thin, parallel heat exchange fins 16 is mounted on tubes l2, only solne oE whicll are shown in Figure l, the chain dotted lines indicatin~ a series of additional fins to fill the nain body of heat exchanger 10. Heat exchanger 10 also has a central stiffener plate 18 although this may be o-nitted iE
desired.
As seen best in Fiqures 1 and 2, heaclers 14 have inner plate portions 20 definin~ a plurality of or)enin(~s 22 formed therein. Openings 22 are su~roun(1ed hy inwardly projecting flanges or ferrules 24 to accommodate upper end portions 26 of tubes 12. Openings 22 are elon~ate in shape to accommodate tubes 12 which are flat or oblong in cross-section, but tubes 12 could be circular in cross-section in which case openings 22 wolllcl be circular as well.
Headers 14 also have outer housing portions 28 joined to plate portions 20. Housing portions 28 have central nipples 30 forming an inlet in one header 14 and an outlet in the other header 14. Headers 14 are typically formed of brass or bronze and they may be cast or Eormed of separate pieces mechanically joined in a Eluid-tight manner, or made in any other convenient manner. The exact configuration of headers 14 is not important to the present invention, it is only necessary that the headers have a plurality of openings 22 corresponding to or in registration with the heat exchange tubes 12, so that fluid may flow from one header through the tubes to the opposite header.
Heat exchans~e tubes 12 are typically formed of brass and are pre-soldered or solder coated on the outside.
The tubes may be seamless or seamed. Heat exchange fins 16 may also be formed of brass or aluminum, tin-plated brass being preferable, so that the fins 16 may be soldered to tubes 12, as described further below. It will be appreciated, however, that other materials could be used for the headers, the fins and the tubes, and further that the various components could be connected or assembled by brazing, by soldering or even by adhesive or elastomer bonding, whichever is most appropriate for the materials used. All of these methods of connection or assembly, for the purposes of this disclosure, come within the term "sealing" as it refers to the tube to header joints.
Referring in particular to Figure 2, it will be seen that fins 16 also have flanges or ferrules 32 which space fins 16 apart at equal intervals. The stiffener plate 18 also has ferrules 34 through which tubes 12 pass.
The open end portions 26 of heat exchange tubes 12 include bulges 36 for positively locating headers 14 relative to fins 16 as will be described further below.
Referring next to Figure 3, the apparatus for forming bulges 36 in tubes 12 is shown. Bulges 36 are shown in chain dotted lines in Figure 3, tubes 12 being shown in full lines prior to the formation of the bulges.
The heat exchange tube manufacturing apparatus inlcudes a pair of fixtures 38 which engage the open ends of tubes 12 by means of hollow dies 40. Each die 40 has an inner wall 42 which is shaped to accommodate the peripheral end of a 1 31 3 1 8~
tube 12 with a relatively loose or sliding fit. Each die 40 also includes an inner wed~e memher 44, which toclether with inner wall 42 forms a V-shaped annular ~roove into which the peripheral end of tube 12 is wedged to form a seal to prevent fluid flow from inside tube 12 out around the peripheral edge of the tube. Each die 40 also includes an outer wall 46 which forms an expansion chamber 48 to allow the formation of bulges 36. Inner wedge memhers 44 also include flow passages 50 for injecting high pressure fluid into tubes 12 as described and explained below.
The assembly of tubes 12 and fins 16 forms a heat exchanger core 51 to which ,headers 14 are assembled to form the complete heat exchanger 10. However the tubes 12 may be formed separately for use in another type of heat lS exchanger as will be described further below with reference to Figures 5 and 6.
To manufacture heat exchange tuhe 12, a plurality of fins 16 are slipped onto tubes 12, so that tlle ferrules 32 of the thusly stacked fins collectively form means for rigidly supporting the tubes intermediate the tube open end portions 26. The fins 16 and the stiffener plate 18, where it is employed, and in particular tlle ferrules 32, 34 thereof form means for preventing lateral expansion of tubes 12 during the manufacture of the tubes. I~owever, - 11 13t31~4 where it is desired to make tubes 12 without fins 16 or a stiffener plate 18, a suitable fixture or other rigid retaining device could be used to preven-t lateral expansion of tubes 12 as will be apparent to those skille~ in the art.
Once fins 16 and stiffener plate 18 are slid onto tubes 12, or some other rigid member supporting device is put into place to prevent lateral expansion of tuhes 12, dies 38 are placed over the open end portions 26 of tubes 12 and forced together to sealingly engage the peripheral ends of the tubes 12. High pressure fluid as indicated by arrows P in Figure 3 is then injected into tubes 12 to cause bulges 36 to be formed in the open end portions 26.
The high pressure fluid is typically compressed gas at a 15 pressure of about 1,000 psi (6900 kPa.). A liquid or other hydraulic fluid could be used for the high pressure fluid, but this would be messy and may necessitate a subsequent cleaning operation. With the bulges 36 formed, fins 16 are held in position forming core Sl, which is then ready for the final steps of the manufacture of heat exchanger 10.
Referring again to Figure 1 and also to Figure 4, headers 14 are then slid over the open end portions 26 of tubes 12 until ferrules 24 engage bulges 36. It will be appreciated that all of the components of heat exchanger 10 - l2 - 1313184 are thus positively located by bulges 36. It will he noted also that ferrules 24 have rounded shoulders 52 and slightly inwardly inclined wall portions 54 (see Fi-Jure 2).
This provides more surface area contact between the tuhes and the headers and this improves the seal and the strength of the tube to hea-3er joints.
Where the components oE heat exchanger ln are formed of brass, pre~erably pre-soldered or tinned ~nd then coated with flux and/or solder paste prior to assembly, the assembly may then be put into a bake oven to complete the soldering operation, and in connection with this a jig 56 is used, as diagramatically illustratec3 in Figure 4.
Jig 56 includes a frame 58 having central retaining elements 66 for holding the assembled heat exchanger core 51 and headers 14 in place. Transverse bearing members 62 support sliding shats 64, wllich slide toward and away from the pre-assembled heat exchanqer lO.
Clamping members 66 are connecte-3 to the inner ends of shafts 64. Clamping members 66 press inwardly against headers 14 to holc3 the headers unto core 5l durin~ the soldering operation. L-shaped members 68 are pivotally mounted in brackets 70, and weights 72 mountec3 on the outer ends of L-shaped members 6~, cause the L-shaped members 6n to bear against sliding shafts 64 and thus ur~e or bias clamping members 66 against headers 14.
Actually, jig 56 is shown in a vertical.
orientation in Figure 4 for illustration purposes only.
Jig 56 would normally be horizontal and hracl<et 70 would he mounted above bearing members 62, so tllat weights 72 move downwardly to bias sliding shafts 64 toward heat excllanger 10. It will be appreciated that tlle conEi-luration of weights 72 is not important, it is only necessary that clamping members 66 be biased toward headers 14 to hold the headers onto core 51 during the soldering operation. In fact, the L-shaped members and weights could be replaced by springs or some other type of biasing means if desired. ~y biasing headers 14 into engagement with core 5l, the header ferrules 24 stay in contact with bulges 3fi, even thou~h core 51 expands and contracts as it is heated and cooled during the soldering operation.
Referring next to Figures 5 and 6, another embodiment of heat exchanger 10 is shown havi.n~ serpenti.ne fins 74 located between and parallel to tubes l2.
Serpentine fins 74 fit snuggly between respective heat exchange tubes 12 and are soldered in place simultaneously with the soldering of heat exchange tuhe 12 to headers l4.
Otherwise, the heat excllanger of Figures 5 and 6 5 is - 1"- 1313184 identical to that of Figure 1. ~o make the bulges 36 in heat exchange tubes 12, however, the rigid members surrounding the tubes, such as the stacked fins 16 shown in Figure 3 would be rernoveable af-ter the bulge forming operation. For this purpose, the stack of fins would be in two halves or split in a plane intermediate and parallel to the longer sides of the stack of fins. Alternatively, and perhaps preferrably, a solid, two-part mold would be used in place of the stack of fins.
From the above, it will be appreciated that the manufacturer of the heat exchanger of the present invention results in a product with very close dimensional tolerances, good tube to header seal and joint strength with reliable soldered joints. Even where the heat exchanger core is assembled and soldered prior to fitting the headers onto the core, the soldering of the headers to the core does not result in displacement or relocation of the fins or dimensional variations in the spacing between the headers.
In the past, heat exchan~ers have heen made consisting of a plurality o discreet heat exchancle tuhes mounted in and communicating with common headers. Such heat exchangers typically have a plura]ity of stacked, transverse, heat transfer fins connected to the tubes, or serpentine heat transfer Eins located hetween and parallel to the tubes. These heat exchangers are often made of brass or tinned steel and the mating surfaces are soldered to produce rigid, leak-proof joints.
A difficulty with the prior art methods of construction is that thermal expansion and contraction during assembly makes it difficult to maintain dimensional tolerances and it often causes leak problems due to poorly formed solder joints. In an attempt to overcome such difficulties, efEorts have heen made to deEorln mating components to mechanically lock or bond them togetller.
However, it is not always possible practically to mechanically lock all of the joints necessary to overcome these difficulties.
Another problem with the prior art construction methods is that heat exchangers are often made from one or more subassemblies which are completed hefore Einal t313184 assembly. If the subassemblies are soldered together and soldering is used in the final assembly, the latter soldering operation can disrupt or dislocate the components of the subassemblies, again playing havoc with the dimensional tolerances of the heat exchan(~ers.
In the present invention, locatin~ bulges are formed in the heat exchange tubes to locate and retain the various components in position durin~ assembly.
Accordin~ to one aspect of the invention, there is provided a method of manufacturing a heat exchange tube for use in a heat exchanger. The method comprises the steps of providing a heat exchange tube having an open end portion and supporting the tube adjacent to the open end portion to prevent lateral expansion of the tube where supported. The distal end of the open end portion of the tube is gripped, and high pressure fluid is injected into the tube to produce a locating bulge in the open end portion spaced ~rom the gripped dista] end.
According to another aspect o the invention, there is provided a method of producing a tube to header joint in a heat exchanger comprising the steps of providing at least one heat exchange tube having an open end portion, providing a header having means defining an opening adapted to accommodate the tube open end portion, and supporting the tube adjacent to the open end portion to prevent lateral expansion of the tube where supported. The distal end of the open end portion of the tube i9 gripped and high pressure fluid is injected into the tube to produce a locating bulge in the open end portion spaced from the gripped distal end. The tube is inserted into the header opening so that the means defining the header opening engages the tube locating bulge, and the joint between the header and the tube is sealed.
According to yet another aspect of the invention, a method of manufacturing a heat exchanger is provided comprising the steps of providing a plurality of parallel heat exchange tubes each having at least one open end portion, providing a header having means defining a plurality of openings adapted to accommodate the tube open end portions, and supporting the tubes adjacent to the open end portions to prevent lateral expansion of the tubes where supported. The distal ends of the open end portions of the plurality of tubes are gripped and high pressure fluid is injected into the tubes to produce locating bulges in the open end portions spaced from the gripped distal ; ends. The tubes are mounted in the header, so that the means defining the header openings engages the tube .
_ 5 - ~313184 locating bulges, and the joints between the header and the tubes are sealed.
According to yet another aspect Oe the invention there is provided a heat exchanger comprising a plurality of parallel heat exchange tubes, each tube having a open end portion. A header is mounted on an communicates with the open end portions, and each tube has a lateral locating bulge adjacent to the header and spacec3 ~rc~m the end of the tube for locating and retaining the header in position.
According to yet another aspect of the invention, there is provided apparatus ~or manufacturing heat exchange tubes for a heat exchanger having a plurality of heat exchange tubes each having an open end communicating with a common header. The apparatus comprises means ~or supporting and preventing lateral expansion of the heat exchange tubes at a location spaced from the ends of the tubes. A fixture is provided for engagin~ the open ends of the tubes prior to assembly with the header, the fixture having means for injecting high pressure fluid into the tubes to produce locating bulges adjacent to and spaced from the ends of the tubes, so that upon assembly of the heat exchanger the locating bulges engage and locate the header in position.
` - 6 - 1313184 According to yet another aspect of the invention there is provided apparatus for manuEacturing a heat exchanger having an assembly o a plurality oE heat exchange tubes mounted in a common header, tlle tuhes having locating bulges formed therein engaging the header. The apparatus comprises a jig for holdin~ the tube and header assembly and means for biasing the header into engagement with the tube locating bulges, so that the tuhe and header assembly can thermally expand and contract during final assembly.
Perferred embodiments of the invention will now be described, by way of example, with reEerence to the accompanying drawings, in which:
Figure 1 is a perspective view, partly exploded and partly broken away, of a preferred embodiment Eor a heat exchanger made according to the present inventi.on;
Figure 2 is a vertical sectional view taken along lines 2-2 of Figure 1 showing part of the assemhled heat exchanger of Figure l;
Figure 3 is a vertical sectional view oE a portion of the apparatus used to form bulges in the ends of the heat exchange tubes shown in Fi~ure 2;
: ' :' ' ~ 7 ~ 1313184 Figure 4 is an elevational dia(lralncltic view oE
the apparatus used in the final assembly o~ the heat exchanger of Figure l;
Figure 5 is a p~erspec~ive view sirnilar to Fiqure 1 but showing another embodirnent Oe a heat exchan(~er made according to the present invention, but having serpentine heat exchange fins; and Figure 6 is an elevational view of a portion oE
the heat exchan~er oE Fi~ure 5 indicate(l by arrow fi in Figure 5.
Referring first to Fi~ure l, a heat exchanger made according to the present invention is generally indicated by reference numeral 10. Heat exchan~er 10 includes a plurality of heat exchan~e tuhes 12 and a pair of opposed headers 14 mounted on and enga~ing the ends of tubes 12. A plurality of thin, parallel heat exchange fins 16 is mounted on tubes l2, only solne oE whicll are shown in Figure l, the chain dotted lines indicatin~ a series of additional fins to fill the nain body of heat exchanger 10. Heat exchanger 10 also has a central stiffener plate 18 although this may be o-nitted iE
desired.
As seen best in Fiqures 1 and 2, heaclers 14 have inner plate portions 20 definin~ a plurality of or)enin(~s 22 formed therein. Openings 22 are su~roun(1ed hy inwardly projecting flanges or ferrules 24 to accommodate upper end portions 26 of tubes 12. Openings 22 are elon~ate in shape to accommodate tubes 12 which are flat or oblong in cross-section, but tubes 12 could be circular in cross-section in which case openings 22 wolllcl be circular as well.
Headers 14 also have outer housing portions 28 joined to plate portions 20. Housing portions 28 have central nipples 30 forming an inlet in one header 14 and an outlet in the other header 14. Headers 14 are typically formed of brass or bronze and they may be cast or Eormed of separate pieces mechanically joined in a Eluid-tight manner, or made in any other convenient manner. The exact configuration of headers 14 is not important to the present invention, it is only necessary that the headers have a plurality of openings 22 corresponding to or in registration with the heat exchange tubes 12, so that fluid may flow from one header through the tubes to the opposite header.
Heat exchans~e tubes 12 are typically formed of brass and are pre-soldered or solder coated on the outside.
The tubes may be seamless or seamed. Heat exchange fins 16 may also be formed of brass or aluminum, tin-plated brass being preferable, so that the fins 16 may be soldered to tubes 12, as described further below. It will be appreciated, however, that other materials could be used for the headers, the fins and the tubes, and further that the various components could be connected or assembled by brazing, by soldering or even by adhesive or elastomer bonding, whichever is most appropriate for the materials used. All of these methods of connection or assembly, for the purposes of this disclosure, come within the term "sealing" as it refers to the tube to header joints.
Referring in particular to Figure 2, it will be seen that fins 16 also have flanges or ferrules 32 which space fins 16 apart at equal intervals. The stiffener plate 18 also has ferrules 34 through which tubes 12 pass.
The open end portions 26 of heat exchange tubes 12 include bulges 36 for positively locating headers 14 relative to fins 16 as will be described further below.
Referring next to Figure 3, the apparatus for forming bulges 36 in tubes 12 is shown. Bulges 36 are shown in chain dotted lines in Figure 3, tubes 12 being shown in full lines prior to the formation of the bulges.
The heat exchange tube manufacturing apparatus inlcudes a pair of fixtures 38 which engage the open ends of tubes 12 by means of hollow dies 40. Each die 40 has an inner wall 42 which is shaped to accommodate the peripheral end of a 1 31 3 1 8~
tube 12 with a relatively loose or sliding fit. Each die 40 also includes an inner wed~e memher 44, which toclether with inner wall 42 forms a V-shaped annular ~roove into which the peripheral end of tube 12 is wedged to form a seal to prevent fluid flow from inside tube 12 out around the peripheral edge of the tube. Each die 40 also includes an outer wall 46 which forms an expansion chamber 48 to allow the formation of bulges 36. Inner wedge memhers 44 also include flow passages 50 for injecting high pressure fluid into tubes 12 as described and explained below.
The assembly of tubes 12 and fins 16 forms a heat exchanger core 51 to which ,headers 14 are assembled to form the complete heat exchanger 10. However the tubes 12 may be formed separately for use in another type of heat lS exchanger as will be described further below with reference to Figures 5 and 6.
To manufacture heat exchange tuhe 12, a plurality of fins 16 are slipped onto tubes 12, so that tlle ferrules 32 of the thusly stacked fins collectively form means for rigidly supporting the tubes intermediate the tube open end portions 26. The fins 16 and the stiffener plate 18, where it is employed, and in particular tlle ferrules 32, 34 thereof form means for preventing lateral expansion of tubes 12 during the manufacture of the tubes. I~owever, - 11 13t31~4 where it is desired to make tubes 12 without fins 16 or a stiffener plate 18, a suitable fixture or other rigid retaining device could be used to preven-t lateral expansion of tubes 12 as will be apparent to those skille~ in the art.
Once fins 16 and stiffener plate 18 are slid onto tubes 12, or some other rigid member supporting device is put into place to prevent lateral expansion of tuhes 12, dies 38 are placed over the open end portions 26 of tubes 12 and forced together to sealingly engage the peripheral ends of the tubes 12. High pressure fluid as indicated by arrows P in Figure 3 is then injected into tubes 12 to cause bulges 36 to be formed in the open end portions 26.
The high pressure fluid is typically compressed gas at a 15 pressure of about 1,000 psi (6900 kPa.). A liquid or other hydraulic fluid could be used for the high pressure fluid, but this would be messy and may necessitate a subsequent cleaning operation. With the bulges 36 formed, fins 16 are held in position forming core Sl, which is then ready for the final steps of the manufacture of heat exchanger 10.
Referring again to Figure 1 and also to Figure 4, headers 14 are then slid over the open end portions 26 of tubes 12 until ferrules 24 engage bulges 36. It will be appreciated that all of the components of heat exchanger 10 - l2 - 1313184 are thus positively located by bulges 36. It will he noted also that ferrules 24 have rounded shoulders 52 and slightly inwardly inclined wall portions 54 (see Fi-Jure 2).
This provides more surface area contact between the tuhes and the headers and this improves the seal and the strength of the tube to hea-3er joints.
Where the components oE heat exchanger ln are formed of brass, pre~erably pre-soldered or tinned ~nd then coated with flux and/or solder paste prior to assembly, the assembly may then be put into a bake oven to complete the soldering operation, and in connection with this a jig 56 is used, as diagramatically illustratec3 in Figure 4.
Jig 56 includes a frame 58 having central retaining elements 66 for holding the assembled heat exchanger core 51 and headers 14 in place. Transverse bearing members 62 support sliding shats 64, wllich slide toward and away from the pre-assembled heat exchanqer lO.
Clamping members 66 are connecte-3 to the inner ends of shafts 64. Clamping members 66 press inwardly against headers 14 to holc3 the headers unto core 5l durin~ the soldering operation. L-shaped members 68 are pivotally mounted in brackets 70, and weights 72 mountec3 on the outer ends of L-shaped members 6~, cause the L-shaped members 6n to bear against sliding shafts 64 and thus ur~e or bias clamping members 66 against headers 14.
Actually, jig 56 is shown in a vertical.
orientation in Figure 4 for illustration purposes only.
Jig 56 would normally be horizontal and hracl<et 70 would he mounted above bearing members 62, so tllat weights 72 move downwardly to bias sliding shafts 64 toward heat excllanger 10. It will be appreciated that tlle conEi-luration of weights 72 is not important, it is only necessary that clamping members 66 be biased toward headers 14 to hold the headers onto core 51 during the soldering operation. In fact, the L-shaped members and weights could be replaced by springs or some other type of biasing means if desired. ~y biasing headers 14 into engagement with core 5l, the header ferrules 24 stay in contact with bulges 3fi, even thou~h core 51 expands and contracts as it is heated and cooled during the soldering operation.
Referring next to Figures 5 and 6, another embodiment of heat exchanger 10 is shown havi.n~ serpenti.ne fins 74 located between and parallel to tubes l2.
Serpentine fins 74 fit snuggly between respective heat exchange tubes 12 and are soldered in place simultaneously with the soldering of heat exchange tuhe 12 to headers l4.
Otherwise, the heat excllanger of Figures 5 and 6 5 is - 1"- 1313184 identical to that of Figure 1. ~o make the bulges 36 in heat exchange tubes 12, however, the rigid members surrounding the tubes, such as the stacked fins 16 shown in Figure 3 would be rernoveable af-ter the bulge forming operation. For this purpose, the stack of fins would be in two halves or split in a plane intermediate and parallel to the longer sides of the stack of fins. Alternatively, and perhaps preferrably, a solid, two-part mold would be used in place of the stack of fins.
From the above, it will be appreciated that the manufacturer of the heat exchanger of the present invention results in a product with very close dimensional tolerances, good tube to header seal and joint strength with reliable soldered joints. Even where the heat exchanger core is assembled and soldered prior to fitting the headers onto the core, the soldering of the headers to the core does not result in displacement or relocation of the fins or dimensional variations in the spacing between the headers.
Claims (35)
1. A method of manufacturing a heat exchange tube for use in a heat exchanger, the method comprising the steps of:
providing a heat exchange tube having an open end portion;
supporting said tube adjacent to the open end portion to prevent lateral expansion of the tube where supported;
gripping the distal end of the open end portion of the tube; and injecting high pressure fluid into said tube to produce a locating bulge in said open end portion spaced from the gripped distal end.
providing a heat exchange tube having an open end portion;
supporting said tube adjacent to the open end portion to prevent lateral expansion of the tube where supported;
gripping the distal end of the open end portion of the tube; and injecting high pressure fluid into said tube to produce a locating bulge in said open end portion spaced from the gripped distal end.
2. A method as claimed in claim 1 wherein the heat exchange tube is provided with two opposed open end portions, and wherein said supporting and gripping steps are performed respectively adjacent to and at the distal ends of each open end portion, so that upon injection of high pressure fluid into said tube, locating bulges are formed in each open end portion of the tube.
3. A method as claimed in claim 1 or 2 wherein the tube is supported along its full length except for any open end portion.
4. A method as claimed in 1 or 2 wherein the tube is supported by providing at least one rigid member surrounding the tube.
5. A method as claimed in claim 1 or 2 wherein the tube is supported by providing a plurality of stacked rigid members surrounding the tube.
6. A method of providing a tube to header joint in a heat exchanger comprising the steps of:
providing at least one heat exchange tube having an open end portion;
providing a header having means defining an opening adapted to accommodate said tube open end portion;
supporting said tube adjacent to the open end portion to prevent lateral expansion of the tube where supported;
gripping the distal end of the open end portion of the tube;
injecting high pressure fluid into said tube to produce a locating bulge in said open end portion spaced from said gripped distal end;
inserting the tube into said header opening to that the means defining the header opening engages the tube locating bulge; and sealing the joint between the header and the tube.
providing at least one heat exchange tube having an open end portion;
providing a header having means defining an opening adapted to accommodate said tube open end portion;
supporting said tube adjacent to the open end portion to prevent lateral expansion of the tube where supported;
gripping the distal end of the open end portion of the tube;
injecting high pressure fluid into said tube to produce a locating bulge in said open end portion spaced from said gripped distal end;
inserting the tube into said header opening to that the means defining the header opening engages the tube locating bulge; and sealing the joint between the header and the tube.
7. A method as claimed in claim 6 wherein the heat exchange tube is provided with two opposed open end portions, and further providing a second header having means defining an opening adapted to accommodate the second open end portion, and wherein the supporting and gripping steps are performed respectively adjacent to and at the distal ends of each open end portion, so that upon injection of high pressure fluid into said tube, locating bulges are formed in each open end portion of the tube, and wherein both headers and the tube are assembled and the joints therebetween sealed.
8. A method as claimed in claim 7 wherein said heat exchange tube is a first heat exchange tube, and further providing a plurality of additional parallel heat exchange tubes having open end portions, and wherein the headers are provided with means defining further openings for accommodating the respective further tube open end portions, and wherein said suporting and gripping steps are performed respectively adjacent to and at the distal ends of each open end portion of at least two heat exchange tubes to form locating bulges in the respective open end portions of said tubes upon injection of said high pressure fluid, and wherein all of said tubes and headers are assembled and the joints therebetween sealed.
9. A method as claimed in claim 8 wherein all of said tubes are formed with locating bulges in the open end portions.
10. A method as claimed in claim 6 or 7 wherein the tube is supported by providing a rigid member surrounding the tube.
11. A method as claimed in claim 8 or 9 wherein the tubes are supported by providing a rigid member surrounding the tubes.
12. A method as claimed in claim 6 or 7 wherein the tube is supported by providing a plurality of parallel rigid members surrounding the tube.
13. A method as claimed in claim 8 or 9 wherein the tubes are supported by providing a plurality of parallel rigid members surrounding the tubes.
14. A method as claimed in claim 6 or 7 wherein the tube is supported by providing a plurality of parallel, stacked rigid members surrounding the tube, and further comprising the step of joining the rigid members to the tube.
15. A method as claimed in claim 6 or 7 wherein the tube is supported by providing a plurality of parallel, stacked rigid members surrounding the tube, and further comprising the step of joining the rigid members to the tube simultaneously with the sealing of the joint between the header and the tube.
16. A method as claimed in claim 8 or 9 wherein the tubes are supported by providing a plurality of parallel, stacked rigid members surrounding the tubes, and further comprising the step of joining the rigid members to the tubes.
17. A method as claimed in claim 8 or 9 wherein the tubes are supported by providing a plurality of parallel, stacked rigid members surrounding the tubes, and further comprising the step of joining the rigid members to the tubes simultaneously with the sealing of the joint between the header and the tubes.
18. A method of manufacturing a heat exchanger comprising the steps of:
providing a plurality of parallel heat exchange tubes each having at least one open end portion;
providing a header having means defining a plurality of openings adapted to accommodate said tube open end portions;
supporting said tubes adjacent to the open end portions to prevent lateral expansion of the tubes where supported;
gripping the distal ends of the open end portions of said plurality of tubes;
injecting high pressure fluid into said tubes to produce locating bulges in said open end portions spaced from said gripped distal ends;
mounting the tubes in the header so that the means defining the header openings engage the tube locating bulges; and sealing the joints between the header and the tubes.
providing a plurality of parallel heat exchange tubes each having at least one open end portion;
providing a header having means defining a plurality of openings adapted to accommodate said tube open end portions;
supporting said tubes adjacent to the open end portions to prevent lateral expansion of the tubes where supported;
gripping the distal ends of the open end portions of said plurality of tubes;
injecting high pressure fluid into said tubes to produce locating bulges in said open end portions spaced from said gripped distal ends;
mounting the tubes in the header so that the means defining the header openings engage the tube locating bulges; and sealing the joints between the header and the tubes.
19. A method as claimed in claim 18 wherein each tube is provided with two opposed open end portions, and further providing a second header having means defining a plurality of openings adapted to accommodate the tube second open end portions, and wherein the supporting and gripping steps are performed respectively adjacent to and at the distal ends of all tube open end portions to form locating bulges in the tube open end portions upon injection of high pressure fluid into the tubes, and wherein all of said tubes and headers are assembled and the joints therebetween sealed.
20. A method as claimed in claim 18 wherein the tubes are supported by providing a plurality of rigid fins having ferrules surrounding the tubes, and further joining the fins to the tubes.
21. A method as claimed in claim 19 wherein the tubes are supported by providing a plurality of rigid fins having ferrules surrounding the tubes, and further joining the fins to the tubes.
22. A method as claimed in claim 19 wherein the headers and tubes are formed of metal such that the joints therebetween can be sealed by soldering.
23 A method as claimed in claim 20, 21 or 22 wherein the fins are joined to the tubes simultaneously with the sealing of the joints between the tubes and headers.
24. A heat exchanger comprising:
a plurality of parallel heat exchange tubes, each tube having an open end portion;
a header mounted on and communicating with said open end portions; and each tube having a lateral locating bulge adjacent to the header and spaced from the end of the tube for locating and retaining the header in position.
a plurality of parallel heat exchange tubes, each tube having an open end portion;
a header mounted on and communicating with said open end portions; and each tube having a lateral locating bulge adjacent to the header and spaced from the end of the tube for locating and retaining the header in position.
25. A heat exchanger as claimed in claim 24 wherein each heat exchange tube has a second opposed open end portion formed with a second lateral locating bulge located adjacent to and spaced from a second end of the tube, and further comprising a second header mounted on and communicating with said second open end portions, the second header engaging the second locating bulges.
26. A heat exchanger as claimed in claim 24 or 25 and further comprising a plurality of rigid fins surrounding and joined to the tubes.
27. A heat exchanger as claimed in claim 24 or 25 and further comprising a plurality of serpentine fins located between, parallel to, and in contact with the tubes.
28. A heat exchanger as claimed in claim 25 and further comprising a plurality of rigid fins extending between the tubes and located intermediate the locating bulges.
29. Apparatus for manufacturing heat exchange tubes for a heat exchanger having a plurality of heat exchange tubes each having an open end communicating with a common header, the appratus comprising:
means for supporting and preventing lateral expansion of the heat exchange tubes at a location spaced from the end of the tubes;
a fixture for engaging said open ends of the tubes prior to assembly with the header, the fixture having means for injecting high pressure fluid into the tubes to produce locating bulges adjacent to and spaced from the ends of the tubes, so that upon assembly of the heat exchanger the locating bulges engage and locate the header in position.
means for supporting and preventing lateral expansion of the heat exchange tubes at a location spaced from the end of the tubes;
a fixture for engaging said open ends of the tubes prior to assembly with the header, the fixture having means for injecting high pressure fluid into the tubes to produce locating bulges adjacent to and spaced from the ends of the tubes, so that upon assembly of the heat exchanger the locating bulges engage and locate the header in position.
30. Apparatus as claimed in claim 29 wherein the supporting means is a rigid member adapted to surround each of the tubes engaged by the fixture.
31. Apparatus as claimed in claim 30 wherein the supporting means is a plurality of spaced-apart stacked fins having ferrules through which the tubes pass.
32. Apparatus as claimed in claim 29 wherein the fixture includes a hollow die having an inner wall adapted to accomodate the peripheral end of a heat exchange tube, an inner wedge member defining a V-shaped annular groove between said inner wall and the wedge member for sealing engagement of the peripheral edges of the tube end, and an outer wall defining an expansion chamber adjacent to the inner wall for permitting lateral expansion of the heat exchange tube therein.
33. Apparatus as claimed in claim 32 wherein said inner wedge member includes a passage adapted to be coupled to a source of high pressure fluid to be injected into a tube.
34. Apparatus as claimed in claim 31 or 33 and further comprising a jig for holding a header and a plurality of heat exchange tubes mounted therein in parallel spaced arrangement, the jig including means for biasing the header into engagement with the heat exchange tubes.
35. Apparatus for manufacturing a heat exchanger having an assembly of a plurality of heat exchange tubes mounted in a common header, said tubes having locating bulges formed therein engaging the header, the apparatus comprising: a jig for holding the tube and header assembly; and means for biasing the header into engagement with the tube locating bulges, so that the tube and header assembly can thermally expand and contract during final assembly.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000594944A CA1313184C (en) | 1989-03-28 | 1989-03-28 | Heat exchanger manufacturing method and apparatus |
| GB9006912A GB2232370B (en) | 1989-03-28 | 1990-03-28 | Heat exchanger and method of manufacturing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000594944A CA1313184C (en) | 1989-03-28 | 1989-03-28 | Heat exchanger manufacturing method and apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1313184C true CA1313184C (en) | 1993-01-26 |
Family
ID=4139811
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000594944A Expired - Lifetime CA1313184C (en) | 1989-03-28 | 1989-03-28 | Heat exchanger manufacturing method and apparatus |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1313184C (en) |
| GB (1) | GB2232370B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2291368B (en) * | 1994-07-22 | 1996-10-23 | Dennis Arthur Summers | Improvements in and relating to metal fixing |
| US5894649A (en) * | 1997-08-28 | 1999-04-20 | Transpro, Inc. | Heat exchanger assembly utilizing grommets and integral cast tanks |
| CA2308581C (en) * | 1997-11-15 | 2006-01-10 | Blissfield Manufacturing Company | Method for assembling a heat exchanger |
| EP2654120A1 (en) * | 2012-04-20 | 2013-10-23 | Magna E-Car Systems GmbH & Co OG | Device for cooling a vehicle battery |
| US11559846B2 (en) | 2020-11-13 | 2023-01-24 | Hamilton Sundstrand Corporation | Brazing by expansion using a spacer |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1302596A (en) * | 1970-03-12 | 1973-01-10 | ||
| IT1097014B (en) * | 1978-07-11 | 1985-08-26 | Nuovo Pignone Spa | IMPROVED SYSTEM FOR THE LOCKING OF A TUBE TO A TUBE PLATE |
| DE2964372D1 (en) * | 1978-10-17 | 1983-01-27 | Austin Rover Group | Improvements relating to heat exchangers |
| US4557128A (en) * | 1982-01-27 | 1985-12-10 | Costabile John J | Apparatus for producing a bulge in thin metal material |
| US4418556A (en) * | 1982-07-12 | 1983-12-06 | Compagnie Europeenne Du Zirconium Cezus | Precision local expansion shaping process and apparatus for metal tubes of substantial length |
-
1989
- 1989-03-28 CA CA000594944A patent/CA1313184C/en not_active Expired - Lifetime
-
1990
- 1990-03-28 GB GB9006912A patent/GB2232370B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| GB2232370A (en) | 1990-12-12 |
| GB9006912D0 (en) | 1990-05-23 |
| GB2232370B (en) | 1993-04-21 |
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