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WO1996036844A1 - Echangeur thermique utilisant des rondelles isolantes - Google Patents

Echangeur thermique utilisant des rondelles isolantes Download PDF

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Publication number
WO1996036844A1
WO1996036844A1 PCT/US1996/006264 US9606264W WO9636844A1 WO 1996036844 A1 WO1996036844 A1 WO 1996036844A1 US 9606264 W US9606264 W US 9606264W WO 9636844 A1 WO9636844 A1 WO 9636844A1
Authority
WO
WIPO (PCT)
Prior art keywords
header
tube
grommet
heat exchanger
body portion
Prior art date
Application number
PCT/US1996/006264
Other languages
English (en)
Inventor
Michael J. Kolb
Original Assignee
Transpro, Inc.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Transpro, Inc. filed Critical Transpro, Inc.
Priority to AU56375/96A priority Critical patent/AU5637596A/en
Publication of WO1996036844A1 publication Critical patent/WO1996036844A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • 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
    • F28F9/06—Arrangements for sealing elements into header boxes or end plates by dismountable joints
    • F28F9/14—Arrangements for sealing elements into header boxes or end plates by dismountable joints by force-joining

Definitions

  • This invention relates to heat exchangers and, more particularly, to motor vehicle heat exchangers utilizing grommets in the tube-to-header joints.
  • Heat exchangers may be liquid-to-air heat exchangers, (e.g., radiators for engine coolant, air conditioning condensers and evaporators, and oil coolers) or may be air-to-air heat exchangers (e.g. charge air coolers).
  • Liquid-to-air and air-to-air heat exchangers are typically composed of an inlet tank or manifold, an outlet tank or manifold, and a large number of tubes extending between the tanks or manifolds which carry the fluid to be cooled. Headers are normally provided on the tanks for mechanical attachment and fluid connection of the tubes. Fins attached to the tubes transfer heat between the liquid or gas inside the tubes and the ambient atmosphere outside.
  • a typical heat exchanger core in this case radiator core 20, is comprised of a plurality of vertical, parallel, spaced tubes 22 between which are interposed heat transfer fins. These fins may be of the flat type 24 or the serpentine type 26 in the composite core depicted in Fig. 1. Any of these fin styles may include louvers (not shown) to enhance heat transfer.
  • the fins are typically formed of strips of aluminum, brass, copper or other thermally conductive metal or alloy.
  • Flat fins 24 are generally made of sheet metal which has a collar formed about a hole.
  • Tubes 22 may be inserted through the collared openings and a plurality of fins may be stacked in order to make up the fin array within the core.
  • Serpentine fins may extend in a serpentine pattern wherein the strips are configured with a plurality of alternating bends between adjacent tubes. The root of the bend is generally secured by brazing or soldering to the tube. A strip portion between the roots extends between the tubes.
  • serpentine fins 26 the pattern is similar to that of a sine wave, while in serpentine fins 30 (Fig. 2) the pattern is zig-zag.
  • the ends of tubes 22 extend beyond the fin array of core 20 to connect to the headers and tanks.
  • Headers 28a and 28b are at the top and bottom, respectively, of core 20 and are plates having openings therein to receive and seal the upper and lower ends of the tubes 22.
  • Upper and lower tanks 34a and 34b, respectively, are normally secured directly to headers 28a and 28b respectively and contain an inlet 36 and outlet 38 for the heat exchanger.
  • Side support rails 32 or other structure may be used to secure the tanks and headers on either side of the core and enable the completed heat exchanger to be secured within the vehicle or machinery frame.
  • the tubes utilized may be either round or oval, or may be circular with oval ends.
  • Prior art methods of welding tube-to-header joints are disclosed, for example, in U.S. Pat. No. 5,407,004, the disclosure which is hereby incorporated by reference.
  • heat from the hot liquid or air within generally causes the tubes to expand and grow in length due to thermal expansion. Since the tanks or manifolds are fixed with respect to each other by the unit framework or structure, the growth in length of tubes places high mechanical stresses on the tanks and the associated headers, particularly in the area of the joints between the tubes and headers. In addition, the pressure of the hot liquid or hot air within the heat exchanger tends to distort the tanks or manifolds and headers, creating further stresses on the tube-to- header joints. The combination of stress resulting from thermal expansion and internal pressure can result in early failure of heat exchangers. Cracks in the joints between the tubes and the headers are the most common mode of failure. Many approaches have been taken to avoid heat exchanger failures due to thermal expansion and internal pressure.
  • Engine cooling radiators for vehicles have sometimes been designed with resilient tube-to-header joints.
  • Locomotive radiators have been manufactured by the assignee of the present invention for over thirty (30) years using headers of special resilient design as shown in Fig. 3.
  • the headers 28 are made of metal and have oversized holes or openings in them to receive oval brass tubes 22 extending from the radiator core.
  • Fins 24 of the flat plate-type design have collars 25 fitted around the tubes.
  • oval brass ferrules 44 are bonded to the header by molded silicone rubber 40.
  • the ferrules are then soldered to the core tubes extending therethrough to form a leak-free, resilient joint between the tubes and the headers. While this has been an extremely effective design under typical operating conditions for locomotives, it is expensive to produce.
  • radiators for automobiles were produced which utilized round aluminum tubes, aluminum plate fins, aluminum headers and plastic tanks.
  • a sheet of molded rubber provided resilient grommets at each tube hole in the header, and also provided a gasket for sealing the headers to the plastic tanks, which were attached to the headers by means of crimped tabs on the headers.
  • the insertion of the tubes into the rubber grommets in the header holes compressed the rubber of the grommets providing a resilient sealing attachment of the tubes to the headers.
  • considerable force was required to insert all the core tubes into the header holes simultaneously. This design was limited to relatively small units because of the problems of core and header distortion during assembly and because of the close tolerance which was required to accomplish the mating of the core tubes to the header with the desired amount of grommet compression.
  • radiators have also utilized rubber grommets in their tube-to-header joints. These radiators have been designed around individual finned tubes having round ends and oval cross-sections which are finned along most of their length. As in the previous design, sealing of the tubes to the header was accomplished by compression of the grommets between the tubes and the header. However, in this alternative design, the tubes were assembled to the headers individually thereby avoiding high assembly forces. This allowed the construction of very large radiators for heavy construction equipment. However, the use of tubes with round ends limits this design to cores having rather wide tube spacing which results in relatively poor thermal performance compared to most radiator core designs.
  • U.S. Patent Nos. 4,756,361 and 5,205,354 describe a radiator which utilizes tubes which are circular in cross-section throughout their length. This type of design is shown in Fig. 4 in which tubes 22 are pressed through collar openings 25 in flat plate fins 24. The tube ends extend through silicone rubber grommets 42 which are disposed in openings within header plate 28. The grommets have a central peripheral groove and top and bottom lips or flanges which extend outward on the top and bottom of the header plate. Because of its round tubes, this design also suffers from poor thermal performance compared to most radiator designs and must have close tolerances to achieve the required compression of the grommet between the tube and header opening to seal the joint.
  • the core tubes enter the grommets and the header more or less simultaneously.
  • the force required for assembly is very high because of the compression of the rubber grommets needed between the tubes and the header for sealing.
  • the openings in the header are oversized with respect to the tubes, they are smaller than the free outside dimensions of the unstressed grommet, resulting in distortion of the grommet in the header hole prior to tube insertion, making assembly of the core tubes to the header very difficult.
  • very close tolerances are required in the core tube and header hole spacing in order to achieve the desired amount of compression on each grommet. The combination of these* factors makes this type of assembly both difficult and expensive.
  • a heat exchanger comprising a header for a tank, the header having at least one opening for receiving a tube from a heat exchanger core; a tube received in and extending through the header opening; and a resilient grommet sealing the tube to the header to prevent leakage around the tube.
  • the grommet has a body portion extending around a portion of the tube within the header opening, a radially outwardly extending lip at a first end of the body portion external to the header opening, and, when unstressed, a radially inwardly extending lip at a second end of the body portion. The radially inwardly extending lip contacts the tube to form a sealed tube-to- header joint.
  • the radially inwardly extending lip has an unstressed inner diameter less than the outer diameter of the tube within the header opening, and wherein the grommet body portion is forced at least partially radially outward sufficient to contact an edge of the header opening. More preferably, at least a portion of an inner surface of the grommet body portion between the first and second ends does not contact an outer surface of the tube within the header opening and the first end of the grommet body portion is forced at least partially radially inward sufficient to contact the tube.
  • the radially outwardly extending lip may have an outer diameter greater than the diameter of the header opening which is forced at least partially radially outward sufficient to contact an edge of the header opening.
  • the grommet seals the tube-to-header joint between: i) an inner surface of the second end of the body portion and an outer surface of the tube end portion, and ii) an outer surface of the body portion and an edge of the header opening.
  • the grommet body portion when unstressed, is substantially the same as or smaller than the header opening such that the body portion, when received within the header opening, remains substantially undistorted by the header.
  • the present invention provides a method of assembling and sealing a tube-to-header joint in a heat exchanger comprising the steps of: a) providing a header for a tank, the header having at least one opening for receiving a tube from a heat exchanger core; b) providing a tube from a heat exchanger core for insertion within the header opening; c) providing a resilient grommet having a body portion for extending within the header opening, a radially outwardly extending lip larger than the header opening at one end of the body portion, and a radially inwardly extending lip at the other end of the body portion, the inwardly extending lip having an unstressed inner diameter less than the outer diameter of the tube; d) inserting the grommet into the header opening with the inwardly extending lip end first; and e) inserting the tube into the header opening and through the grommet body portion such that the inwardly extending lip contacts the tube to form a sealed tube-to-header joint.
  • the inwardly extending flange is forced at least partially radially outwardly by the tube such that the grommet body portion contacts an edge of the header opening to form a sealed tube-to-header joint and at least a portion of an inner surface of the grommet body portion between the first and second ends does not contact an outer surface of the tube within the header opening.
  • the inwardly extending flange may be forced at least partially radially outwardly by the tube such that the first end of the grommet body portion is forced at least partially radially inward sufficient to contact the tube and the radially outwardly extending lip is forced at least partially radially outward sufficient to contact an edge of the header opening.
  • the present invention provides a grommet for sealing a tube-to-header joint in a heat exchanger wherein the header has at least one opening for receiving a tube end portion from a heat exchanger core.
  • the grommet has a resilient body portion for extending within the header opening the body portion, with the inner diameter of the body portion being larger than the outer diameter of the tube end portion.
  • a radially outwardly extending resilient flange at one end of the body portion, which outwardly extending flange is larger than the header opening; and a radially inwardly extending resilient flange at the other end of the body portion, the inner diameter of the inwardly extending flange, when unstressed, being less than the outer diameter of the tube end portion.
  • a further aspect of the present invention provides a heat exchanger comprising a heat exchanger core having at least two tubes having ends extending outward from a core body with heat transfer fins being disposed between the tubes.
  • the fins are formed from a metallic strip which extends in a serpentine pattern between adjacent tubes.
  • the strip is configured with a plurality of alternating bends such that, within the core body, the root of a bend is secured to a tube and the strip portion between the roots extends between the tubes.
  • the strip alternating bend configuration continues to a strip free end near the tube ends where the strip free end is cut at a root of a bend.
  • the serpentine pattern of the strip portion near the tube ends may be compressed to permit the tube ends to extend outward from the core body so that the strip free ends contact the header to limit insertion of the tube ends into the header openings.
  • the heat exchanger core contains a plurality of tubes and heat transfer fins disposed between the tubes, and substantially all of the strip free ends near the tube ends are cut at the root of a bend.
  • the heat exchanger also preferably includes at least one tank having a header containing openings for receiving the tube ends, and resilient grommets within the header openings sealing the tubes to the header to prevent leakage around the tubes, whereby the strip free ends contact an end of the grommets.
  • the invention provides a method of manufacturing a heat exchanger comprising the steps of: a) providing a heat exchanger core having a plurality of tubes with spaced tube ends extending outward from the core; b) providing a tank; c) providing a header for the tank, the header having a plurality of spaced openings for receiving tube ends from the heat exchanger core, the spacing of the header openings being greater than the spacing of the tube ends; d) welding the header to the tank and shrinking the length of the header so that the spacing of the header openings conforms to the spacing of the tube ends; e) inserting resilient grommets into the header openings; and f) inserting the tube ends into the header openings and through the grommets to seal the core to the tank.
  • the header has a central section with openings for receiving the tube ends and a pair of flanges connected to, and on opposite sides of, the header central section.
  • the header flanges have a height of at least about 2.5 cm and the header is welded to the tank along edges of the flanges distant from the header central section so that the strength of the connection between the flanges and the header central portion is unaffected by heat generated during welding of the flanges to the tank.
  • Fig. 1 is a front elevational view of a typical prior art heat exchanger core and header assembly.
  • Fig. 2 is a perspective view of a typical assembled radiator of the prior art.
  • Fig. 3 is a cross-sectional view of a prior art tube-to-header joint which utilizes molded silicone rubber.
  • Fig. 4 is a cross-sectional view of a prior art tube-to-header joint which utilizes grommets.
  • Fig. 5 is a cross-sectional view of one embodiment of the grommet utilized in the present invention.
  • Fig. 6 is a cross-sectional view of the grommet of Fig. 5 installed in a header opening and receiving a tube end.
  • Fig. 7 is a cross-sectional view of the grommet of Fig. 5 installed in a header opening with the tube fully inserted and sealed.
  • Fig. 8 is a side elevational view of the grommet of Fig. 5.
  • Fig. 9 is a top plan view of the grommet of Fig. 5.
  • Fig. 10 is a top plan view of a header having openings for oval tubes prior to insertion of the grommet of the present invention.
  • Fig. 11 is an end elevational view of the header of Fig. 10.
  • Fig. 12 is a cross-sectional view of an alternative embodiment grommet in a tube-to-header joint.
  • Fig. 13 is a cross-sectional view of another alternative embodiment grommet in a tube-to-header joint.
  • Fig. 14 is an elevational view, partially in cross-section, showing a header mated with the tubes and fins in a core utilizing grommets in the tube-to-header joint.
  • Fig. 15 is an exploded perspective view of the assembly of the tank, header and grommets of the invention.
  • Fig. 16 is a perspective view of an assembled charge air cooler made in accordance with the present invention.
  • This invention is directed primarily toward an air-to-air heat exchanger used as a charge air cooler, or intercooler, for turbocharged or supercharged engines. However, it may also be utilized in any other type of heat exchanger, for example, those discussed in the background of the invention, such as radiators, oil coolers and the like.
  • the present invention provides a heat exchanger which has a resilient tube-to-header joint to minimize tube-to-header stresses due to a combination of a thermal expansion of the tubes and internal pressure in the tanks.
  • Preferably oval tubes are utilized for close tube spacing for optimum heat transfer performance of the core, although other tube shapes and cross-sections may be utilized.
  • the present invention provides easy and inexpensive assembly through the use of specifically configured grommets which do not rely on compression of the grommet between the tube and the inside of the header hole for sealing. This reduces the force required for assembly and requirements for close part tolerance.
  • the design of the grommets as described herein simplifies insertion of the grommets into the header and further facilitates unit assembly.
  • the present invention also contemplates an improved header configuration and an improved fin configuration in the area of the core adjacent to the header.
  • Grommet 50 is preferably made of a silicone rubber or other resilient, flexible or compliant polymer or other material which provides good sealing against the other components of the heat exchanger which are typically made of a metal or alloy.
  • Grommet 50 comprises a body portion having an opening therein to receive the tube from a heat exchanger core.
  • a radially outwardly extending lip or flange 58 is disposed at a first, upper end of the body portion and a radially inwardly extending lip or flange 60 is disposed at a second, lower end of the grommet.
  • Outward lip 58 has an angular portion 62 extending down and inward to the outer wall section 54 of the grommet, which extends straight downward from there to the lower end of the grommet.
  • Inner wall 56 extends straight downward from the upper end of the grommet until it reaches radially inwardly projecting lip 60.
  • both upper and lower lips 58 and 60 have generally rounded corners. However, any other shape or configuration of these lips may be utilized.
  • the body portion of grommet 50 may be conical in shape.
  • grommet 50 has a configuration which conforms to the shape of the oval openings 52 in header plate 28 which are sized to receive tubes 22 from the header core (see Fig. 10).
  • Header 28 has an opening 52 for each tube which is to be connected to the header/tank assembly.
  • the term "oval” refers to any non-circular shaped axial cross-section (i.e. perpendicular to the axis of the tube) having a generally smoothly curving periphery, such as an ellipse or a rectangle with rounded corners, or other obround or egg shape.
  • Fig. 6 shows the insertion of grommet 50 into header 28 and the beginning of insertion of lower end 48 of tube 22 into the grommet in the direction indicated by the arrow.
  • Header opening 52 is provided with generally the same configuration as the cross-section of tube end 48, although the header opening is larger in dimension (both major diameter and minor diameter).
  • the unstressed diameter "d" of grommet 50 (Fig. 5) is substantially the same as, or less than the diameter of header opening 52. This ensures that the grommet 50, when inserted into the header 52 openings as shown in Fig. 6, is substantially undistorted.
  • grommet 50 is inserted first into header opening 52. Following that, tube 22 is inserted into the grommet. Since the upper lip or flange 58 is the only portion of the grommet extending radially outwardly from the body, insertion from one side of the header is facilitated.
  • the grommet is inserted from the so-called "air" side 27 of the header, i.e., the portion of the header which is exposed to surrounding atmosphere external to the heat exchanger.
  • the lower end of the grommet having the inwardly projected end is inserted into the header opening first and, after insertion, extends from the so- called “fluid" side 29 of header 28, i.e., the side which is exposed .to the air or liquid inside the heat exchanger.
  • outward lip 58 remains external to header opening 52 and preferably contacts air side surface 27 of the header.
  • the inward extending lip 60 of grommet 50 has a diameter essentially the same as or less than the outer diameter of tube end 48, upon full insertion of the tube from the air side of the header through the grommet, contact will be made between inward grommet lip 60 and the outside surface of tube end 48 (Fig. 7).
  • the unstressed inner diameter of the body portion of grommet 50 is preferably greater than the outer diameter of tube end 48 over the major portion of the grommet height. This provides for easy entry and lead-in of the tube into the grommet and, after full entry, will provide a gap between a substantial portion of the outer surface of the tube end 48 and the inner diameter of the grommet 50 body portion within the header opening.
  • the inner diameter of the inward lip 60 is less than the outer diameter of tube end 48 so that, after full insertion of the tube as shown in Fig. 7, the outer wall of the lower end of grommet 50 is forced radially outward.
  • the tube stretches the grommet in the lower region and flexes its walls to provide good sealing contact between the inward lip 60 and the outside surface of tube end 48 and form a tight seal around the tube.
  • the expansion of inward lip 60 bulges or forces outward grommet outer wall portion 54 which locks against and forms a seal with the edge of header opening 52 to prevent the grommet from slipping back out of the header opening. Sealing of the grommet to the tube and the header is further enhanced by the action of internal pressure inside the tank/header assembly which serves to force the lip 60 radially inward into tighter contact with both the tube and the header, in the manner of an O-ring seal.
  • grommet design may be employed, such as those shown in
  • the unstressed grommet 72 at the right, without the tube inserted has an outer surface 84 which curves inward near the lower end before terminating in inward lip 80.
  • outer wall 84 fits snugly against the header opening when the grommet is first inserted, but is not oversized so as to distort the shape of the grommet.
  • Upper outward lip or flange 76 also may be rectangular in cross-section, as shown. However, the same principle of operation exists for the alternative grommet 72 configuration. As shown in the left portion of Fig.
  • tube 22 is inserted through the body of the grommet so that lower inward lip 80 seals against tube 22 and the grommet outer body portion is thereby forced or stretched outward to lock and seal against the edge of the header opening. There also remains a gap between a portion of the exterior wall of tube 22 within the grommet and grommet inner wall 88.
  • Fig. 13 again shows another alternative embodiment 74 of the grommet of the present invention.
  • the principal difference with previously described grommet 50 is that lower inward lip 82 also includes an outwardly extending portion to enhance the ability of the grommet to lock into the edge of header 28 opening when the tube 22 is inserted through the body of the grommet.
  • the result of the invention remains the same, that is, the sealing without compression of the grommet between the tube and header which permits greater tolerances in the location of tubes vs. header holes.
  • assembly of the heat exchanger utilizing the grommet configuration of the present invention may commence by inserting the grommet into the header, the header being optionally joined or formed to the tank in a prior step by any conventional method known in the art.
  • the tubes for the heat exchanger core are then inserted from the same side as the grommet was inserted.
  • the tubes may be inserted individually, one at a time, or preferably may be inserted simultaneously because of the low assembly force required as a result of the grommet configuration.
  • the core may be connected to the tanks to complete the heat exchanger assembly.
  • Fins 70 are made of thin metal strip such as copper, aluminum or brass having high thermal conductivity. These serpentine fins 70 are bent in a series of alternating bends so that the roots 92 of the bends contact tubes 22. The fins are soldered or brazed to the tubes at these roots 92 to ensure good thermal conductivity between the tube 22 and the fins 70. The portions of fin 70 between alternating roots 92 transfer the majority of the heat from the fluid inside the tube to the ambient air outside of the heat exchanger. Fins 70 continue along tube 22 and terminate at the free end 93 of the strip near tube end 48.
  • the serpentine pattern of fin 70 is compressed near tube end 48 prior to brazing or soldering the fins to the tubes in the manufacture of the heat exchanger core. More preferably, the strip is also cut so that free ends 93 of substantially all of fins 70 terminate at a position where a root would be, i.e., closely adjacent to or in contact with the tube outer surface, rather than at a point somewhere between the tubes. After assembly, this compression or "combing" of the fins permits the tube ends 48 to extend a length "I" to provide a proper location of the tubes into the tank/header assembly and helps provide locking of the grommet in place in the header openings.
  • the compressed pattern of the fins 70 contacts and pushes against the top lip 58 portion of grommet 50 to hold it securely in place. Additionally, since the free end 93 of fin 70 is cut at the root, instead of at random, this avoids the accidental introduction of portions of the fins into the area between the grommet and the tube.
  • header plate 28 is only slightly greater than the width of header openings 52 (and only slightly greater than the major diameter of tube 22 shown in phantom line inserted into the header opening). This minimizes header flexing and achieves maximum header strength.
  • the header is preferably made with a relatively flat or planar central section which contains the openings for the tube ends. As shown in Fig. 1 1 , on opposite sides of the header central section are flanges 64, 66 extending approximately 90 degrees from the plane of the central section. Since the entire header is preferably made of a single stamped or formed metal strip, the thickness of the header central portion and flanges is generally uniform throughout.
  • flanges 64, 66 may be attached by welding or other means to the tank (Fig. 15).
  • the height "h" of flanges 64, 66 are such that, when the distant end of the header flange is welded to the tank, the strength of the area of connection between the flanges and the header central portion is unaffected by heat generated during the welding.
  • flange height h is at least about 2.5 cm. It has also been found that, as a result of the operation of welding the header
  • the length "a" of the header shrinks. Consequently, the present invention also provides that the header length "a", along with the spacing of the header openings, be initially fabricated to be greater than the spacing between the tubes extending from the completed heat exchanger core. For example, an additional initial length of 0.003 inches per foot (0.25 mm/m) of header length has been found to be desirable. As the header is welded to the tank, it shrinks the length of the header so that the spacing between the header openings is reduced to conform to the spacing of the tube ends.
  • header 28 is assembled to the conforming opening in the side of tank 100, preferably by welding as previously described.
  • An additional tank opening 102 is provided as either an inlet or an outlet for the completed tank and header assembly.
  • the grommets 50 may be inserted into the header openings 52 after welding of the header to the tank.
  • the individual grommets are connected by a web 68 made out of the same resilient material as the grommets themselves.
  • heat exchanger 110 comprises the core 94 which has structural core extensions 96 on the upper and lower sides thereof. These core extensions have overhanging ends which mate with corresponding portions of the tank. The tube ends are aligned with and partially inserted into the corresponding grommet openings in the headers, and an entire tank/header/grommet assembly is then pushed onto the core at either end.
  • a mechanical fastener 104a, 104b is provided to connect the tanks 100a, 100b on either end of core 94. This mechanical fastener is provided so that the tanks may be easily disassembled from the core for servicing.
  • any type of mechanical fastener may be utilized, such as a bolt or snap-type fitting.
  • a snap-on arrangement is preferred which uses a ramped protrusion extending from the tanks which snaps into corresponding openings in the ends of support member 96.
  • the header is first assembled to the tank in the manner described above.
  • the resilient grommet is inserted into the opening in the header with the inwardly extending lip end first.
  • the tube or assembly of tubes is then inserted into the header opening through the grommet body such that the inwardly extending lip connects the tube to form a sealed tube- to-header joint.
  • accurate positioning of the tubes with respect to the header holes is not critical since the configuration is not dependent on precise compression of the grommet between the tube and the inside of the header hole for sealing.
  • the mechanical assembly of the joint between the header and tubes and between the core and tanks permits easy disassembly of the unit for replacement of the core in the event of damage in the field.
  • the mechanical joint is possible only because of resilient tube-to-header joints which minimize tube-to-header stresses due to thermal expansion and result in very low stress in the joints between the structural pieces and the tanks. Additionally, the eventual assembly of the charge air cooler or other heat exchanger into the vehicle where it is attached to other structure provides sufficient additional mechanical support so that welding of the side supports is unnecessary.
  • This invention provides a heat exchanger such as a charge air cooler with greatly reduced stresses on the tube-to-header joint caused by thermal expansion of the tubes and tank internal pressure. Tests have shown that such a design will have a life of up to ten times greater than that of a conventional brazed joint charge air cooler. For example, typical brazed joint charge air coolers develop small leaks in the tube-to-header joint after only 1,000 cycles of thermal cycle testing and fail completely due to major leaks after 3,000 to 4,000 cycles. Charge air coolers with resilient grommet tube-to-header joints made have survived 10,000 cycles without leaking. The invention also provides resilient grommet tube-to-header joints without the need for compressing the rubber of the grommet between the tube and the inside of the header hole.
  • This invention eliminates the high forces required for compression of the rubber during insertion of the assembly of tubes into the grommet.
  • This invention further provides for greater tolerances in the location of the tubes with respect to the header holes than current designs and lowers manufacturing costs because the design is not dependent for sealing on compression of the grommet rubber the tubes and the insides of the header holes.
  • This invention also provides for use of oval tubes, grommets and header holes thus allowing closer spacing of the core tubes compared to using round tubes, grommets and header holes. This closer tube spacing in the core will provide optimum heat transfer performance.

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

Abstract

Cette invention concerne un échangeur thermique qui utilise des rondelles isolantes élastiques (50) pour rendre étanche un tube (22) relié au collecteur (28) afin d'éviter les fuites. La rondelle isolante (50) présente un corps disposé autour d'une partie du tube à l'intérieur de l'ouverture (52) du collecteur, une lèvre (58) débordant radialement vers l'extérieur à une extrémité dudit corps et, lorsqu'elle n'est pas sollicitée, une lèvre (60) débordant radialement vers l'intérieur au niveau de l'autre extrémité du corps qui est en contact avec le tube (22). Lorsque la rondelle est logée à l'intérieur de l'ouverture du collecteur (52), le corps de cette rondelle isolante n'est sensiblement pas déformé par le collecteur (28). Les ailettes (70) sont agencées en serpentin de sorte que, à l'intérieur du corps du faisceau de réchauffeur, la racine d'un coude (92) est fixée à un tube (22) et l'extrémité libre (93) est coupée à la racine d'un coude (92). A proximité des extrémités (48) du tube, le serpentin est comprimé de façon à permettre aux extrémités du tube (48) de se déployer vers l'extérieur du corps du faisceau de réchauffeur et ce, de façon à ce que les extrémités libres (93) soient en contact avec la rondelle isolante (50) pour limiter l'introduction des extrémités (48) du tube à l'intérieur des ouvertures (52) du collecteur.
PCT/US1996/006264 1995-05-18 1996-05-03 Echangeur thermique utilisant des rondelles isolantes WO1996036844A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU56375/96A AU5637596A (en) 1995-05-18 1996-05-03 Heat exchanger utilizing grommets

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US44427795A 1995-05-18 1995-05-18
US08/444,277 1995-05-18

Publications (1)

Publication Number Publication Date
WO1996036844A1 true WO1996036844A1 (fr) 1996-11-21

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1996/006264 WO1996036844A1 (fr) 1995-05-18 1996-05-03 Echangeur thermique utilisant des rondelles isolantes

Country Status (3)

Country Link
AU (1) AU5637596A (fr)
CA (1) CA2167642A1 (fr)
WO (1) WO1996036844A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1161318A4 (fr) * 1999-03-10 2004-09-29 Transpro Inc Echangeur thermique soude a construction d'oeillets
AT503775B1 (de) * 2006-05-16 2009-07-15 Sterner Franz Anordnung zur abgedichteten durchführung von einzeladerkabeln durch öffnungen, z.b. eines gehäuses
WO2018147997A1 (fr) * 2017-02-07 2018-08-16 Caterpillar Inc. Dispositif de refroidissement intermédiaire air/air à joint coulissant tube-collecteur
RU206339U1 (ru) * 2020-08-17 2021-09-06 Иван Сергеевич Демидов Втулка

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3434746A (en) * 1966-08-10 1969-03-25 Amp Inc Flexible tube coupling
US3693710A (en) * 1970-04-20 1972-09-26 Sidney S Drosnin Radiator fin-tube construction and method
US4645000A (en) * 1986-04-21 1987-02-24 General Motors Corporation Tube and fin heat exchanger
US5205354A (en) * 1992-01-28 1993-04-27 Lesage Philip G Vehicle radiator and method of making

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3434746A (en) * 1966-08-10 1969-03-25 Amp Inc Flexible tube coupling
US3693710A (en) * 1970-04-20 1972-09-26 Sidney S Drosnin Radiator fin-tube construction and method
US4645000A (en) * 1986-04-21 1987-02-24 General Motors Corporation Tube and fin heat exchanger
US5205354A (en) * 1992-01-28 1993-04-27 Lesage Philip G Vehicle radiator and method of making

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
WELDING HANDBOOK, Section One, Fundamentals of Welding, Edited by ARTHUR PHILLIPS, c. 1968, pages 3.54-3.55. *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1161318A4 (fr) * 1999-03-10 2004-09-29 Transpro Inc Echangeur thermique soude a construction d'oeillets
AT503775B1 (de) * 2006-05-16 2009-07-15 Sterner Franz Anordnung zur abgedichteten durchführung von einzeladerkabeln durch öffnungen, z.b. eines gehäuses
WO2018147997A1 (fr) * 2017-02-07 2018-08-16 Caterpillar Inc. Dispositif de refroidissement intermédiaire air/air à joint coulissant tube-collecteur
US10823515B2 (en) 2017-02-07 2020-11-03 Caterpillar Inc. Tube-to-header slip joint for air-to-air aftercooler
RU206339U1 (ru) * 2020-08-17 2021-09-06 Иван Сергеевич Демидов Втулка

Also Published As

Publication number Publication date
AU5637596A (en) 1996-11-29
CA2167642A1 (fr) 1996-11-19

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