MXPA01009042A - Welded heat exchanger with grommet construction - Google Patents

Abstract

A heat exchange comprising a core assembly (20) having a plurality of tubes (22) connected by an array of fins (24), with ends of the tubes extending from the fin array on at least one side of the core assembly (20) and resilient, polymeric grommets (40) disposed around the tube ends. The exchanger includes a tank portion for receiving fluid entering or leaving the core assembly and a header portion (38) having openings to receive the tube ends and grommets (40) to create a sealed, fluid-tight tube-to-header joint. There is provided a reinforcing member across the opening of the tube ends extending from the tube end opening to the portion of the tube end around which the grommet (40) is disposed without substantially extending into the fin array portion of the core assembly (20). The header portion (38) comprises a substantially planar base having openings therein with side (32) and end walls (34) extending out of the plane of the base and connected by one or more fluid-tight welds to the tank portion (60).

Description

HEAT INERCAMBIADQR SOLDIER WITH CONSTRUCTION OF OJALES Technical Field This invention relates to heat exchangers, and more particularly to heat exchangers of motor vehicles that use eyelets in the joints of the tube to the head and deposits welded to the head.

BACKGROUND OF THE ART Heat exchangers, in particular those used in motor vehicles, may be liquid-to-air heat exchangers (for example, radiators for engine coolant, air-conditioning condensers and evaporators, and oil coolers) or may be air-to-air heat exchangers (eg, air-charge refrigerators). The liquid-to-air and air-to-air heat exchangers are typically composed of an inlet or collector tank, an outlet tank or collector, and a large number that extend between the tanks or collectors carrying the fluid to be cooled , the heads are normally provided in the tubes for the mechanical connection and fluid connection to the tanks. The fins attached to the tubes transfer heat between the liquid or gas inside the tubes and the atmosphere of the outside environment, a mechanical frame or structures is usually included to provide structural strength to the assembly and provide means to mount the unit to the vehicle or other machinery in which it is used. The tubes used can be either round or oval, or they can be oval with circular ends. Prior art methods for welding pipe joints to the head are described, for example, in U.S. Patent No. 5,407,004, the disclosure of which is incorporated herein by reference. In use, the heat of the hot liquid or air inside generally causes the tubes to expand and grow in length due to thermal expansion. Since the tanks or collectors are fixed relative to each other by the unit or structure frame, the growth and length of the tubes place the high mechanical stresses in the tanks and the associated heads, particularly in the area of the joints between the tubes and the heads. In addition, the pressure of hot liquid or hot air inside the heat exchanger tends to deform the tanks or manifolds and heads, creating additional tension in the joints of pipe to the head. The combination of stress results from thermal expansion and internal pressure can result in early failure of heat exchangers. Fissures in the joints between the tubes and the heads or in the tubes immediately adjacent to these joints are the most common failure mode. Many approaches have been taken to avoid heat exchanger failures due to thermal expansion and internal pressure; most approaches fall into one of two categories: 1) those that improve the resistance of areas prone to failure and 2) those that provide elasticity in areas prone to failure. Approaches that provide elasticity are of interest to designers as they provide a solution to the stress of thermal expansion and internal pressure with a greater economy than any approach that must provide more material to achieve an improvement in strength. The cooling radiators of the engine for vehicles have sometimes been designed with elastic joints from the tube to the head. The locomotive radiators have been manufactured by the assignee of the present invention for more than thirty years (30) using heads of special elastic design. In this design, the metal heads have holes or extra-large openings in them to receive oval brass tubes extending from the radiator core. Oval brass splints are placed inside the openings in the head. These splints are attached to the head by molded silicone rubber. The splints are then soldered to the core tubes which extend therethrough to form a leak-free elastic joint between the tubes and the heads. The fins of the flat plate type design have collars attached around the tubes. The heads are mechanically attached to the tanks, just as with bolts. While this has been an extremely effective design under typical operating conditions for locomotives, it is expensive to produce. In the 70's, the radiators for automobiles that were produced used round aluminum tubes, aluminum plate fins, aluminum heads and plastic tanks. A molded rubber sheet provided resilient eyelets in each tube hole in the head, and also provided a gasket to seal the heads of the plastic reservoirs, which were attached to the heads by means of bent grafts in the heads. The insertion of the tubes into the rubber eyelets in the holes of the head comprised the rubber of the eyelets providing an elastic seal union of the tubes to the heads. However, considerable force was required to insert all the core tubes into the holes of the heads simultaneously. This design was limited to relatively small units due to core problems and distortion of the head during assembly and due to the closing tolerances that were required to achieve the union of the core tubes to the head with the desired amount of compression of the head. buttonhole. Other radiators have also used rubber eyelets in their joints from the tube to the head. These radiators have been designed around tubes with individual fins having round ends and oval cross sections having fins along most of their length. As in the previous design, the seal of the tubes to the head was achieved by compressing the eyelets between the tubes and the head. However, in this alternative design, the tubes were assembled to the heads individually avoiding high assembly forces. This allowed the construction of very large radiators for heavy construction equipment. However, it has been found that the use of tubes with round ends limits this design to cores that have rather wide tube space, which results in relatively poor thermal performance compared to most radiator core designs. U.S. Patent Nos. 4,756,361 and 5,205,354 disclose a radiator using circular tubes and tube ends that extend through the silicone rubber eyelets that are disposed in openings within a head plate. U.S. Patent Nos. 5,052,475 and 5,226,235 describe the use of circular eyelets to seal circular tubes in tin-welded deposits and welded deposits, respectively. British Patent No. 29,777 describes the use of round tubes and eyelets with a tubular plate integrally fused with the head. Currently, air-to-air heat exchangers use a welded bronze aluminum core that has oval tubes that are produced commercially. The aluminum heads that have extra-large oval openings are welded to melt the aluminum manifolds. The oval silicone rubber eyelets, otherwise similar to those described in the aforementioned '361 patent are inserted into the openings in the heads of the welded tanks. In the '361 patent mentioned above, the heads are intended to be connected to the inlet and outlet tanks by means of bolts with a seal gasket, or other similar means. US Patent No. 5,226,235 discloses a radiator made of a unitary core consisting of tubes and fins, connected to the tank assemblies consisting of welded tank and head assemblies in which the elastic eyelets have been inserted after welding. This '235 patent provides advantages over the' 361 patent in that the welded tank and the head assembly is more compact than an assembly by bolts with a sealing gasket. In addition, the design of a welded tank is quite flexible and can be done quickly to suit any application. Nevertheless, a difficulty with the '235 patent is that it requires that all the weld of the reservoir / head assembly be completed before assembling the elastic eyelets to the assembly. This is established by being necessary to prevent heat damage to the elastic eyelets. However, it makes assembly of the unit core assembly to the tank / head assemblies particularly difficult, since one can only see one side of the eyelets and the access to the other side of the eyelets is denied to aid in assembly. For example, it can assist in the insertion of the core tubes into the eyelets and the tube ends will be fixed with removable round tips. However, in the one-piece tank / head design, recovery of the balls after insertion is practically impossible. Additionally, accessing the side of the remote eyelets on the tube insertion side may be useful for inserting tubes in another way. For example, supporting or supporting the remote side of the eyelet during tube insertion makes tube insertion easier and prevents the removal of eyelets. This is, of course, impossible with a one-piece tank / head assembly described in the '235 patent. It may be advantageous if the critical head tube seals are made and inspected with full access for both the air side and the fluid side of the seals. The core assembly can be tested separately and corrections of the pipe joints to the head can be made, if necessary, before the deposits are joined. Having in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide an improved heat exchanger and method for making the heat exchanger using eyelets in the pipe joints to the head, which head can weld to the tank after the insertion of the eyelets. It is a further object of the present invention to provide an improved method of assembly by means of the heat exchanger in which the core assembly can be tested separately and corrections can be made to the pipe joints to the head, if necessary before they are joined. deposits.

Description of the Invention The foregoing and other objects and advantages, which will be apparent to one skilled in the art, are achieved in the present invention which is directed, in a first aspect, to a heat exchanger comprising a core assembly having a plurality of tubes connected by a fin arrangement, whose ends of the tubes extend from the fin arrangement on at least one side of the core assembly, and elastic, polymeric eyelets disposed around the ends of the tube. Preferably, the eyelets of the heat exchanger are made of a heat-resistant silicone rubber. The heat exchanger includes a reservoir portion for receiving fluid entering or leaving the core assembly and a head portion having apertures for receiving the tube ends and eyelets to create a tube seal to the fluid tight head sealed. The head portion comprises a base having openings therein and side walls extending out of a plane of the base and connected by one or more fluid-tight welds to the reservoir portion. The side walls extend a sufficient distance to dissipate the heat generated to the welds and maintain the heat generated from adversely affecting the sealing capacity of the eyelets when the welds are made between the reservoir and the head portion with the ends of the weld. tube and eyelets received in the openings of the head portion. The head portion of the heat exchanger can be comprised of a unitary metal sheet having bent, or tempered, side walls extending from the base. The side and end walls of the head portion can be joined at corners thereof to create an open box structure. Preferably, the base of the head is substantially planar while the side and end walls are substantially perpendicular to the plane of the base. In the preferred embodiment, the structure also includes a reinforcing member through the opening of the tube ends extending from the tube end opening to the tube end portion around which the eyelet is disposed without extending substantially within the fin assembly portion of the core assembly. In another aspect, the present invention relates to a heat exchanger comprising a core assembly having a plurality of tubes connected by a fin arrangement, with ends of the tubes extending from the fin arrangement on at least one side of the tube. Core assembly and elastic polymeric eyelets are arranged around the tube ends. The heat exchanger includes a reservoir portion for receiving fluid entering or leaving the core assembly and a head portion having openings for receiving the tube ends and eyelets to create a tube seal to the sealed fluid tight head . The head portion comprises a substantially flat base having openings therein with the side and end walls extending out of the plane of the base and connected by one or more fluid-tight welds to the reservoir portion. The side of the end walls extend a sufficient distance to dissipate the heat generated when making the welds and keep the heat generated from adversely affecting the sealing capacity of the eyelets when the welds are made between the head portion reservoir with the tube ends and eyelets received in the head portion openings. In still another aspect, the present invention provides a method for making a heat exchanger. The method comprises initially providing a core assembly having a plurality of tubes connected to a fin arrangement with the ends of the tubes extending from the fin arrangement on at least one side of the core assembly and the elastic polymeric eyelets arranged around the core. the tube ends. The provided eyelets can be comprised of a heat-resistant silicone rubber. A deposit is also provided, having an open end portion for receiving fluid entering or leaving the core assembly, and a head portion with a base having openings for receiving the tube ends and the side walls extending out of the plane of the base. In the preferred embodiment, the sidewalls extend a sufficient distance to dissipate the heat generated in the weld from the reservoir to the head portion and maintain the heat adversely affecting the sealing capability of the eyelets when welding with the tube ends and eyelets received in the head portion openings. The method also includes joining the head portion to the assembly in the core upon receiving the tube ends and eyelets in the head portion openings to create a tube seal to the sealed fluid tight head. The head portion is then welded to the open end portion of the reservoir to create one or more fluid tight welds. In the preferred embodiment, welding occurs when the tube ends and eyelets received in the head portion openings without adversely affecting the sealing capability of the eyelets in the tube joint to the head. The method may also include the step of folding the edge portions or extracting the portions of the unitary sheet of the metal comprising the head portion to create the side walls extending from the base, and may also include joining the side walls and the extreme walls at the corners thereof to create an open box structure. The side and the end walls can be bent to positions substantially perpendicular to the plane of the substantially flat base. In the preferred embodiment, the tube ends include a reinforcing member inserted through the opening of the tube extending from the tube end opening to the portion of the tube end around which the eye is disposed without substantially extending within the fin assembly portion of the core assembly. A further aspect of the invention relates to a heat exchanger comprising a core assembly, which has a plurality of tubes connected by a fin arrangement, with the tubes in between extending from the fin arrangement on at least one side of the tube. core assembly and elastic polymeric eyelets arranged around the tube ends. A reinforcing member is disposed through the opening of at least a portion of the tube ends and extends from the tube end opening to the position of the tube end around which the eyelet is disposed without substantially extending into the tube. the fin arrangement portion of the core assembly. The heat exchanger includes a reservoir for receiving fluid entering or leaving the core assembly and a head portion having openings that receive the tube ends and eyelets to create a seal of the tube to the sealed fluid sealed head. The head portion of this embodiment comprises a base having openings therein and side walls extending out of a plane of the base and connected by one or more fluid-tight welds to the reservoir. The side walls extend a sufficient distance to dissipate the heat generated when making the welds, and keep the heat from adversely affecting the sealing capacity of the eyelets when the welds are made between the reservoir of the head portion with the ends of tube and eyelets received in the portion openings of the heads. The features of the invention believed to be novel and the characteristic elements of the invention are set forth with particularity of the appended claims. The figures are for illustration purposes only and are not drawn to scale. The invention itself, however, both for the organization and method of operation, can be better understood by reference in the detailed description which follows taken together with the accompanying drawings in which: Figure 1 is a perspective view of a preferred unitary brazed core block employed in the present invention. Figure 2 is a perspective view of the preferred box head used in the present invention. Figure 3 is a perspective view of the preferred die-cut template of the box head of Figure 2. Figure 4 is a perspective view of the preferred molded eyelets employed in the present invention. Figure 5 is a side elevational view of a step for assembling the core assembly tubes in the openings of the head plate to make the heat exchanger of the present invention. Figure 6 is a side elevation view of a subsequent assembly step s that of Figure 5. Figure 7 is a side elevational view of an assembly step subsequent to that of Figure 6. Figure 8 is a view in perspective of the box head of Figure 2 assembled on the unit brazed core block of Figure 1. Figure 9 is a top plan view of the tubes fixed within the box head of Figure 8. Figure 10 is an extreme elevation view of a tube fixed within the box head along line 10-10 of Figure 9. Figure 11 is a side elevational view of a tube fixed within the box head along the line 11-11 of Figure 9. Figure 12 is an exploded view of a preferred reservoir that is welded onto the box head of Figure 2. Figure 13 is a perspective view of the tanks assembled on the containers. box heads and assembly e of the unit brazed core block of Figure 8.

MODES FOR CARRYING OUT THE INVENTION In describing the preferred embodiment of the present invention, reference will be made herein to Figures 1-13 of the drawings in which similar numbers refer to similar features of the invention. Characteristics of the inventions are not necessarily shown to scale in the drawings. This invention is directed primarily to air-cooled radiators that utilize a liquid refrigerant for automotive applications. However, it can also be used for any other type of heat exchanger, for example, those discussed in the background of the invention such as oil coolers, air charge coolers and the like. The present invention provides a structural assembly and method that allows the head to be welded to the tank after the insertion of the eyelets into the openings of the head, without damaging the eyelet material with heat. Preferably oval tubes are used in the heat exchanger for the closed tube space for optimum heat transfer performance of the core, although other tube configurations and cross sections may be used. As shown in Figure 1, the heat exchanger of the present invention preferably uses a core block or assembly 20 comprising an arrangement of parallel tubes 22, preferably oval tubes, between which an arrangement of transfer fins 24 is interposed. hot. These fins may be of any flat type or coil type as shown in the core shown in Figure 1. Either of these fin styles may include gratings to improve heat transfer. The tubes and fins are typically formed of aluminum, bronze, copper, or other metal or thermally conductive alloy. The coil fins 24 may extend in a serpentine pattern wherein the strips are configured with a plurality of alternate pleats between the adjacent tubes 22. The crease root is generally secured by the brazing or soldered tin to the tube. Alternatively, the fins can be made of metal foil having a collar formed around a hole. The tubes can be inserted through the collar opening and a plurality of fins can be stacked in order to make the fin arrangement within the core. The ends 23 of the tubes 22 extend beyond the exposure of fins of the core 20 to connect to the heads and reservoirs used in the heat exchanger. The preferred head used in the present invention is shown in Figure 2. The head 30 comprises a generally rectangular body having a portion 38 of substantially planar or planar base of L length and width within which the openings 36 of head that generally conforms to the configuration of the tube ends 23. The openings 36 of the head portion are preferably oval and are arranged in a single row as shown, although multiple rows of tubes may be employed. As used herein, the term "oval" refers to any axial cross section in a non-circular manner (ie, perpendicular to the axis of the tube) having a generally smooth curved periphery such as an ellipse or a rectangle with rounded corners , otherwise ovoid or egg. Being of oval cross-sectional shape, such tubes and openings will have a diameter in one direction greater than the diameter in another direction (usually perpendicular), which is referred to herein as the "largest diameter" and the "smallest diameter" respectively. While oval shaped tubes and, consequently, oval shaped head openings and eyelets are preferred, another tube opening and eyelet configurations may be used, such as circular or rectangular. For reasons discussed below, in order to accommodate the eyelets, the the head openings 36 are longer than the tube ends 23. The width of the head plate portion 38 is only slightly larger than the larger diameter of the openings 36 of the head to decrease the flexure of the head and achieve maximum strength of the head portion. Forming a box-like configuration for the head 30 are straight vertical side walls 32 and end walls 34 extending upwardly from the plane of the base 38. The side walls 32 face each other along opposite edges along the length of each other. long sides of plate portion 38, corresponding to the length of L, while the vertical straight end walls 34 face each other along the shorter ends of the plate portion 38, corresponding to the width. The side walls 32 have free edges 32b in the upper portions thereof while the end walls 34 have free edges 34b along the upper portions thereof. The head edges 32b and 34b are connected. by means of welds to the portions of the heat exchanger reservoir as will be discussed below. In order to allow adequate heat dissipation and to prevent excessive heat buildup in the vicinity of the head openings 36, it is preferred that the height H of the side walls 32 and the end walls 34b are carefully controlled. For example, a head used in motor vehicles, it is preferred that the side height and the end walls are at least about one and a half inches () (1.25 mm), more preferably at least about one inch (1) ( 2.5 mm). The height of the head side and end wall is also preferred to be less than about two inches (2) (5.0 mm), more preferably less than about one and one-half inches (VA), (3.75 m). The height of the head side and the end wall must be high enough to avoid excessive temperatures that develop in the eyelets as a result of welding the edges 32b, 34b, to the tank, but not so high as to require material excessive. The head can be formed by any conventional manufacturing process, such as casting, die cutting or tempering. The preferred die-cut template of the head 30 is shown in Figure 3. The head plate portion 38, the side walls 32 and the end walls 34 are preferably formed from a solid unitary metal sheet, eg, copper, bronze or aluminum The vertical side walls 32 are formed by bending or folding along the line indicated by 33 while the vertical end walls 34 are formed by folding or folding along the lines indicated by 35. The end portions 32a of the side wall 32 then makes contact with the side portions 34a of the end wall 34 along a vertical joint that can be joined and sealed by welding to form the corners. Such welds are preferably made prior to the insertion of the eyelets since the corners formed by the end portions 32a, 34a close relatively to the head openings 36. For tempered heads, the side walls 32 and the end walls 34 (Figure 2) are resold from a unitary sheet of metal and extend upwardly from the base or plate portion 38. The eyelets are the preferred sealing means between the tubes and the head portion openings. The preferred eye of the preferred invention is shown in Figure 4. The eyelet 40 preferably makes a heat-resistant silicone rubber or other elastic, flexible or ductile polymer or other material that provides good sealing against the others. heat exchange components, and which has adequate heat resistance to avoid affecting the sealing ability of the eyelet when the head is welded to the reservoir while the eyelets are in the openings of the head.The preferred eyelet is made of rubber silicone, such as a compound ST 125785-V-RED, which can be obtained from Dow Corning Corporation.Silicone rubber is a high temperature silicone rubber that includes a vulcanizing agent and meets ASTM D2000.The other relevant properties of the material of Preferred eyelet were as shown in the following Table 1. Table 1 Property Value Hardness Shore A 50 Resistance to Tension, kgf / cm2 90 Tear Strength kgf / cm 18 Elongation,% 300 Specific Gravity 1.16 Spreading Speed,% 3.3 Compression Set,%, 22hr, @ 177 ° C 11 Temperature Range, ° C from less than 55 to more than 250 Change after Aging by Heat 250 ° C / 72 hours: Purity Points. 2 Tension,% -19 Elongation,% -10 In laboratory tests with heads of the invention, it was determined that the eyelets were capable of withstanding temperatures of up to 260 ° C-315 ° C (500 ° F-600 ° F). The eyelets 40 comprise a body portion having an opening therein for receiving the core from a heat exchanger core. A flange or flange extending radially outward is deposited at a first upper end of the body portion and a flange or flange extending radially inward is disposed at a second lower end of the eyelet. It should be understood that, the relative directional terms are used herein to refer only together with the drawings and the eyelet and other components may be used in some position, including those different from those shown. The eyelet 40 has a configuration conforming to the conformation of the oval openings 36 in the head portion 38 which are dimensioned to receive the tube ends 23 from the head core (Figure 1). The assembly of the tube ends of the head core 20 within the openings 36 of the head using the eyelets is shown in Figures 5, 6 and 7. In Figure 5, both the tube 22 and the eye 40 are initially aligned along the direction of the length of the tube. As shown in Figure 6, the eyelet 40 is inserted into the head opening 36, and the tube end 23 is brought into contact with the eyelet. Then, as shown in Figure 7, the tube end 23 is forced through the elastic inner opening of the eyelet 40 such that the tube 22 is received completely through the eyelet within the head opening 36. With reference to Figure 4, the eyelets are preferably molded into groups of more than 1, for example group of three (3), so that three can be inserted at the same time in the head openings. Once all the eyelets are inserted in the head openings, all the tube ends 23 from the core assembly 20 are inserted at the same time through the eyelet openings. Preferably the inside diameter of the flange into the eyelet is smaller than the outer diameter of the end of the tube, so that after all the tube insertion, the outer wall, the lower end of the eyelet 40 is forced radially outwardly. Due to the elasticity of the eyelet material, the tube reaches the eyelet in the lower region and flexes its walls to provide a good sealing contact between the inward rim and the outer surface of the tube end 23 to form an airtight seal around the rim. tube. Additionally, the expansion of the inward flange bulges or forces out the outer wall portion of the eye that locks and forms a seal with the edge of the head portion opening in contact with the eye. Then, as shown in Figure 7, the tube end 23 is forced through the elastic inner opening of the eyelet 40 such that the tube 22 is received completely through the eyelet within the head opening 36. With reference to Figure 4, the eyelets are preferably molded into groups of more than 1, for example group of three (3), so that three can be inserted at the same time in the head openings. Once all the eyelets are inserted in the head openings, all the tube ends 23 from the core assembly 20 are inserted at the same time through the eyelet openings. Preferably the inner diameter of the flange in the eyelet is smaller than the outer diameter of the tube end, so that after all the tube insertion, the outer wall, the lower end of the eyelet 40 is forced radially outwards. Due to the elasticity of the eyelet material, the tube reaches the eyelet in the lower region and flexes its walls to provide a good sealing contact between the inward rim and the outer surface of the tube end 23 to form an airtight seal around the rim. tube. Additionally, the expansion of the flange inward bulges or forces out the outer wall portion of the eye that locks and forms a seal with the edge of the head portion opening to prevent the eyelet from sliding backward from the portion opening. of the head. The seal of the buttonhole to the tube and the head portion is further improved by the action of an internal pressure within the reservoir / head assembly 60 which serves to force the flange radially inward in more tight contact with the tube and the head portion. in the form of a ring-shaped seal. The inner surface of the upper end of the eyelet can also be forced inward to make contact with the outer surface of the tube to seal against leakage. Additionally, the lower outer edge of the outer flange may also seal against the edge of the head portion opening to provide an additional seal. In Figure 8 the preferred box head 30 is shown attached and assembled to the core block 20 by means of eyelets 40 which hold the tube ends 23 within the openings 36 of the head to create a sealed tube-to-head joint. A head is shown in both the upper and lower portions of the core block attached to both the upper and lower tube ends. In order to provide a counter collapse of the oval tubes during insertion into the eyelets in the openings of the head, an internal reinforcing member or stiffener can be used through the opening of one or more of the tube ends as shown in Figures 9, 10 and 11. The tube stiffener 50 comprises a short flat length of metal or alloy comparable with the tube material which can be brazed or welded in place. Unlike the internal fins that may be used in some oval tubes, the tube stiffener 50 extends only from about the end 23 of the tube to the portion of the tube surrounded by the eyelet, and does not substantially extend further into the tube body. 22 within the fin arrangement of the core assembly. Although a stiffener 50 is shown in approximately the central portion of the tube opening, additional stiffeners can be employed along the opening of the tube end 23. Such stiffeners 50 are particularly useful for tubes having a diameter of less than 0.5 inch (1.3 cm) to 1 inch (2.5 cm) or more. In some cases, the internal stiffeners can extend by approximately 1 inch (2.5 cm) from each end of each tube to provide internal support against collapse under the comprehensive sealing forces of the eyelet. To limit the degree of stiffeners to only the end areas of the tubes, the internal flow restriction of the tubes is decreased. The assembly of the reservoir to the head 30 which receives the end of the tube through the eyelets is shown in Figure 12. A reservoir portion 60 having an open end formed by the side walls 62 and the end walls 64 are aligned by the head 30. The lower edges 62b of the side walls of the reservoir and the lower edges 64b of the end walls of the reservoir align with the side wall edge 32b of the head and the edges 34b of the end wall of the head, respectively . After contacting the respective edges of the reservoir 60 and the head 30, the gaskets formed therewith can be welded by MIG or TIG welding procedures., or other well-known welding methods, to form one or more seals or sealed fluid-tight joints. Both MIG and TIG welding procedures are preferred because they decrease the heat flow in the head 30. The completed heat exchanger is shown in Figure 13 in which a reservoir 60 is welded to both the upper head portions as inferior. The upper reservoir 60 has inlets 66 for receiving the liquid refrigerant, which then travels through the reservoir and the tubes in the core section 20 to the lower reservoir 60 and through the outlet 68. Preferably, a structural side piece of welded or brazed welded mechanically fastened to the entrance and exit of the tank and the walls. Thus, the heat exchanger and the method depicted herein, use elastic tube head gaskets, which have a long service life compared to common heat exchangers due to the reduction or elimination of the tube to the stresses of the tube. head. The present invention facilitates the assembly of the head with eyelets to the core block since both sides of the eyelets are accessible during assembly. This allows the use of ball points in the tubes if necessary (to facilitate the insertion of the tube ends through the eyelets), reinforcing the remote side of the eyelet to resist the forces of the pipe insertion tube and Inspection of the finished tube to the head joints on both sides of the head. The present invention also makes it possible to test leaks of the core assembly and pipe fit to the head gasket before the tanks join. The present invention preferably makes use of multiple eyelets connected together to reduce the possibility of separation of the eyelets during insertion of the tube. Additionally, the internal stiffeners prevent the collapse of the tube ends due to the compression sealing forces of the eyelet. The present invention allows the use of quenched, cast or fabricated and welded deposits, all for welding to the box heads. This provides manufacturing flexibility required to provide models, prototypes and short series production using fabricated and welded tanks, while using quenched or cast tanks for low volume, high volume production. While the present invention has been particularly described in conjunction with a specific preferred embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims would cover any alternative, modification and variation as it falls within the true scope and spirit of the present invention. In this way, having described the invention, what is claimed is:

Claims (31)

1. CLAIMS 1. A heat exchanger comprising: a core assembly having a plurality of tubes connected by a fin arrangement, with ends of the tubes extending from the fin arrangement on at least one side of the core assembly; elastic, polymeric eyelets arranged around the tube ends; a reservoir portion for receiving fluid entering or leaving the core assembly; a head portion having openings that receive the tube ends and eyelets to create a tube seal to the sealed fluid sealed head, the head portion comprises a base having openings therein and side walls extending out of a plane of the base and connected by one or more fluid-tight welds to the reservoir portion, the side walls extend a sufficient distance to dissipate the heat generated by making the welds adversely affecting the sealing capability of the eyelets when the welds are made between the reservoir of the head position while the ends of the tube and the eyelets are received in the head portion openings. The heat exchanger of claim 1, wherein the head portion comprises a unitary sheet of metal having bent side walls extending from the base. The heat exchanger of claim 1, wherein the head portion comprises a unitary sheet of metal having bent side walls and end walls extending from the base, the side walls and the end walls are joined at the corners of it to create an open box structure. 4. The heat exchanger of the claim 3, wherein the head base is substantially planar and the side and end walls are substantially perpendicular to the plane of the base. The heat exchanger of claim 1, wherein the head portion comprises a unitary sheet of metal having tempered side walls extending from the base. The heat exchanger of claim 5, wherein the head base is substantially planar and the side and end walls are substantially perpendicular to the plane of the base. 7. The heat exchanger of claim 1, wherein the buttonholes comprise a heat-resistant silicone rubber. 8. The heat exchanger of claim 1, wherein at least a portion of the tube ends includes a stiffening member through the end opening, the stiffening member extends from the tube end opening to the portion of the tube end around which the eye is disposed without substantially extending the fin assembly portion of the core assembly. 9. A heat exchanger comprising: a core assembly having a plurality of tubes connected to a fin arrangement, with ends of the tubes extending from the fin arrangement on at least one side of the core assembly; elastic, polymeric eyelets arranged around the tube ends; a reservoir portion for receiving fluid entering or leaving the core assembly; a head portion having openings that receive the tube ends and eyelets to create a tube-to-head seal to the sealed fluid, the head portion comprises a substantially flat base having openings therein and end and side walls that extend out of a plane of the base and connected by one or more fluid-tight welds to the reservoir portion, the side and end walls extend a sufficient distance to dissipate the heat generated when making the welds that affect them. adversely sealing the buttonholes when the welds are made between the reservoir of the head position while the tube ends and the eyelets are received in the head portion openings. 10. The heat exchanger of the claim 9, wherein the head portion comprises a unitary metal sheet having bent or bent side walls and end walls extending substantially perpendicular to the plane of the base, the side walls and the end walls are attached to corners of the base. the same to create an open box structure. 11. The heat exchanger of the claim 10, wherein the eyelets comprise a heat-resistant silicone rubber. The heat exchanger of claim 9, wherein at least a portion of the tube ends includes a stiffening member through the end opening, the stiffening member extends from the tube end opening to the end portion of the tube around which the eye is disposed without substantially extending into the fin arrangement portion of the core assembly. 13. A method for making a heat exchanger comprising the steps of: a) providing a core assembly having a plurality of tubes connected by a fin arrangement, with ends of the tubes extending from the fin arrangement in at least one side of the core assembly, and elastic, polymeric eyelets arranged around the tube ends; b) providing a reservoir having an open end portion for receiving fluid entering or leaving the core assembly; c) providing a head portion having openings for receiving the tube ends, the head portion comprises a base having openings therein and side walls extending out of the plane of the base, the side walls extend to a sufficient distance to dissipate the heat generated by welding the reservoir to the head portion and preventing the heat of the weld from adversely affecting the sealing capability of the eyelets when the weld is made while the tube ends and eyelets are received in the openings of the head portion; d) attaching the head portion to the core assembly upon receiving the tube ends and eyelets in the head portion openings to create a tube seal to the sealed fluid tight head; and e) after attaching the head assembly to the core assembly, welding the head portion to the open end portion of the reservoir to create one or more fluid-tight welds while the tube ends and eyelets are received in the openings of the head. head portion, without adversely affecting the sealing ability of the eyelets in the tube joint to the head. The method of claim 13, wherein the head portion comprises a unitary sheet of metal and further includes the step of folding the edge portions of the sheet to create side walls extending from the base. The heat exchanger of claim 13, wherein the head portion comprises a unitary metal sheet and further includes the steps of: i) folding the edge portions of the sheet to create side walls and end walls that are extend from the base, and ii) join the side walls and the end walls at the corners thereof to create an open box structure. The method of claim 15, wherein the head base is substantially planar and the side and end walls are bent to positions substantially perpendicular to the plane of the base. 17. The method of claim 13, wherein the head portion comprises a unitary metal sheet and further includes the step of restoring portions of the sheet to create side walls extending from the base. 18. The method of claim 13, wherein step a) includes providing eyelets comprising a heat-resistant silicone rubber. The method of claim 13, further includes the step of inserting at least a portion of the tube ends of a reinforcing member through the openings from the end, the reinforcing member extends from the tube end opening to the portion of the tube end around which the eyelet is disposed without substantially extending into the fin arrangement portion of the core assembly. 20. A heat exchanger comprising: a core assembly having a plurality of tubes connected to a fin arrangement, with ends of the tubes extending from the fin arrangement on at least one side of the core assembly; elastic, polymeric eyelets arranged around the tube ends; a reinforcing member disposed through the opening of at least a portion of the tube ends, the reinforcing member extends from the tube end opening to the tube end portion around which the buttonhole is disposed. without substantially extending in the fin arrangement portion of the core assembly a reservoir for receiving fluid entering or leaving the core assembly and including a head portion having openings that receive the tube ends and the eyelets to create a seal of sealed fluid tight head tube. The heat exchanger of claim 20, wherein the head portion comprises a base having openings therein and side walls extending out of a plane of the base and connected with one or more fluid-tight welds at the deposit, the sidewalls extend a sufficient distance to dissipate the heat generated by making the welds adversely affecting the sealing capacity of the eyelets when the welds are made between the reservoir and the head portion while the tube ends and the eyelets are received in the head portion openings. 22. The heat exchanger of the claim 20, wherein the head portion comprises a unitary sheet of metal having bent side walls and end walls extending from the base, the side walls and the end walls are attached to the corners thereof to create a open box structure. 23. The heat exchanger of claim 20, wherein the eyelets comprise a silicone rubber with heat resistance.
2. 2 . A method for manufacturing a heat exchanger comprising: providing a reservoir having an open end portion for receiving fluid entering or leaving the core assembly, the reservoir being free of a head; providing a combined core assembly and the head; i) the core assembly has a plurality of tubes connected by a fin arrangement, with ends of the tubes extending from the fin arrangement on at least one side of the core assembly, and ii) the head has openings with elastic eyelets, polymers disposed therein to receive the tube ends, the head further comprises a base having openings therein and side walls extending out of a plane of the base, the walls They extend far enough to dissipate the heat generated by welding the reservoir to the head and prevent the heat of the weld from adversely affecting the sealing capability of the eyelets when the weld is made while the ends of the tube and the eyelets are receive in head portion openings; the head is joined to the core assembly with the tube ends received in the elastic, polymer eyelets which are in turn received in the head openings to create a seal of the tube to the sealed fluid sealed head; and after welding the head to the open end portion of the reservoir to create one or more fluid-tight welds, the weld occurs while the tube ends and eyelets are received in the openings of the head, without adversely affecting the capacity of the head. sealing of the eyelets in the joint of the tube to the head. The method of claim 24, wherein the head comprises a unitary sheet of metal bent along the edge portions of the sheet to create side walls extending from the base. The method of claim 24, wherein the head comprises a unitary sheet of metal bent along the edge portions of the sheet to create side walls and end walls extending from the base, the side walls and end walls are joined at corners thereof to create open box structure. 27. The method of claim 26, wherein the head base is substantially planar and the side and end walls are bent to positions substantially perpendicular to the plane of the base. The method of claim 24, wherein the head comprises a unitary sheet of metal having tempered positions of the sheet creating side walls extending from the base. 29. The method of claim 24, wherein the eyelets comprise a heat-resistant silicone rubber. 30. The method of claim 24 further includes, in at least a portion of the tube ends, a reinforcing member through the end openings, the reinforcing member extends from the tube end opening to the portion of the tube end around which the eye is disposed without substantially extending the fin arrangement portion of the core assembly. The method of claim 24, further comprising providing a pair of reservoirs and heads, and providing a core assembly having tube ends extending from the fin arrangement on the two sides of the core assembly with the heads which are joined on both sides of the core assembly by tube ends received in the elastic eyelets, polymeric that are received in turn in the head openings to create a pair of sealed fluid-sealed tube-to-head joints, includes thereafter welding the heads to the open end portions of the reservoir to create fluid-tight welds, Welding occurs while the tube ends and eyelets are received in the openings of the head, without adversely affecting the sealing ability of the eyelets in the joints of the tube to the head.