MXPA97000009A - Process for producing flat heat exchange tubes - Google Patents

Abstract

A process for producing flat heat exchange tubes, using a lower component member which comprises a lower wall portion, side wall portions and reinforcing wall portions projecting integrally therewith, and a upper component member connected between the opposite side wall portions of the lower component member, placing the upper component member over the lower component member on the opposite side wall portions and then brazing the upper and lower component members. The process using a rolling mil 33 comprising a central work roll 35 and a plurality of planetary work rolls 36 which are provided around the central work roll by a predetermined distance circumferentially thereof. The central work roll 35 of the rolling mill 33 is formed with annular grooves in its entire periphery to make side wall portions and reinforcing wall portions. The process is to form a lower component member by making an aluminum blazing sheet (30) pass through the opening between the central work roll 35 and the planetary work 36 continuously.

Description

PROCESS TO PRODUCE FLAT HEAT EXCHANGE PIPES BACKGROUND OF THE INVENTION The present invention relates to a process for producing flat heat exchange tubes, more particularly to flat heat exchange tubes for similar condensers, evaporators and heat exchangers for use in automobile radiators. JP-B No. 45300/91 discloses a capacitor for use in automobile radiators comprising a pair of heads arranged to the right and to the left in parallel and separated from each other, parallel flat heat exchange tubes each bonded at their ends opposite the two heads, corrugated fins arranged in an air flow space between the adjacent heat exchange tubes and welded to the adjacent tubes, an inlet pipe connected to the upper end of the left reed, an outlet pipe connected to the lower end of the right reed, a left partition provided within the left reed and placed above the midpoint thereof, and a right partition provided within the right reed and placed below the middle portion thereof, the number of tubes of heat exchange between the left pipe and the left partition,, the number of heat exchange pipes between the part The left partition and the right partition and the number of heat exchange tubes between the right partition and the outlet pipe decrease in descending order. A refrigerant flowing in the inlet pipe in a vapor phase flows in a zigzag through the condenser before flowing out of the outlet pipe in a liquid phase. The capacitors of the described construction are called parallel flow or multiflow condensers, have high efficiencies, reduced pressure losses and are supercompact and have been widely used in recent years instead of conventional coil condensers. It is required that the heat exchange tube for use in the condenser has a resistance to pressure since the refrigerant is introduced therein in the form of a high pressure gas. To meet this requirement and to achieve a high heat exchange efficiency, the heat exchange tube is made of a hollow aluminum extrusion comprising flat upper and lower walls and a reinforcing wall connected between the upper and lower walls and which extends longitudinally. To improve the efficiency of heat exchange and to compact the condenser, it is desirable that the flat heat exchange tube have a reduced wall thickness and the minimum possible height. In the case of extrudates, however, the extrusion technique imposes limitations on the reduction of the height of the tube and the thickness of the wall. To solve this problem, the Patent No. 5,553,377 discloses a method for producing a flat heat exchange tube comprising a flat metal tube having parallel coolant passages therein and comprising upper and lower flat walls and a plurality of reinforcing walls connected therebetween. upper and lower walls, which extend longitudinally of the tube and separated from each other by a predetermined distance. The known method comprises rolling a forge of a metal plate having a thickness greater than the thickness of the heat exchange tube that will be produced with a pair of upper and lower rollers one of which has parallel annular grooves thus reducing the thickness of the forge in relation to the thickness of the wall of the specific tube with the peripheral surfaces of the rollers to form a flat portion serving at least for the upper wall or the lower wall and form vertical protrusions projecting from the flat portion integrally with the same and provide the reinforcement walls with annular grooves.

However, the method described has the problem of the use of production equipment having a large size since the metal plate forge needs to pass through a plurality of rolling mills. An object of the present invention is to provide a process for producing flat heat exchange tubes with production equipment which can be compact in its entirety.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides a process for producing a flat heat exchange tube having coolant passages parallel therein and comprising upper and lower walls to which fins will be attached, and a plurality of reinforcing walls connected between the upper walls. and lower, which extend longitudinally of the tube and spaced apart from each other by a predetermined distance, using a rolling train comprising a central working roller and a plurality of planetary working rolls arranged around the periphery of the central and separate work roll. of this circumferentially, the central working roll or the planetary work rolls with parallel annular grooves being formed at the periphery of the roll, the process comprising the rolling of a forge of a metal plate by a rolling train and thus reducing the thickness from the forging to a specific value with the peripheral surface of the central work roll and the peripheral surfaces of the planetary work rolls to form a flat portion serving at least one of the upper and lower walls and form vertical protrusions projecting from the planar portion integrally and providing the reinforcing walls annular grooves. Therefore, the simple rolling train produces a laminated metal plate comprising a flat portion which provides at least the upper wall or the lower wall, and vertical projections integral with the flat portion and supplying the reinforcing walls. Preferably, the rolling train has a guide shoe between each pair of immediately adjacent planetary working rolls and means for decentering the guide shoe towards the central working roll. This suppresses the longitudinal elongation of the shape of the metal plate while the forge passes through the rolling train, further inhibiting the forging from bulging between the adjacent planetary work rolls. Consequently, the work roll or rollers having the parallel grooves provide the laminated metal plate with a specific cross-sectional configuration. In order to obtain the laminated metal plate of the reliable specific cross-sectional configuration, it is desirable to arrange the plurality of planetary work rolls relative to the central work roll so that the separation of the laminate gradually decreases towards the forging direction of the forging. the metal plate. It is also desirable that a roller formed with parallel annular grooves and parallel shallow annular grooves between each two adjacent annular grooves be used as a central working roller or as each of the planetary rollers to form heat transfer areas by increasing the low protrusions which project from the planar portion integrally therewith when forming vertical projections projecting from the planar portion integrally therewith and providing the reinforcing walls with the annular grooves. It is also desirable that a roller formed with parallel annular grooves and projections provided at predetermined intervals in each of the grooves and having a height less than the depth of the groove be used as a central working roller or as each of the rollers of planetary work, so that when the vertical protrusions projecting from the flat portion integrally with it and providing the reinforcement walls are formed with annular grooves, a plurality of cutouts are formed at the predetermined interval at the upper edge of each of the projections to form holes for effecting communication between the parallel coolant passages. The communication holes in the reinforcing walls allow the coolant to flow through the coolant passages parallel to the full width of the heat exchange pipe, whereby portions of the coolant are mixed together to eliminate coolant temperature differences between the passages. The opening ratio which is the percentage of all communication holes in each reinforcing wall to the wall is preferably 10 to 40%. Within this range, the opening ratio ensures a satisfactory thermal conductivity which ensures that the heat exchange tube has a greatly improved heat exchange efficiency. If the ratio is less than 10%, the thermal conductivity does not increase, whereas when the ratio exceeds 40%, the conductivity is no longer increased, but only an increased coefficient of friction results. The opening ratio within the range of 10 to 40% is preferable from 10 to 30%, and more preferably to approximately 20%. The communication holes are dimensioned in such a cross-sectional manner as to allow the refrigerant to flow smoothly therethrough between the adjacent passages, to free them from any possibility of clogging with a weld flow during welding and to not affect the Pressure resistance of the heat exchange tube. The passage of the communication holes is such that the holes will not reduce the resistance of the tube pressure while allowing the refrigerant to flow smoothly through the reinforcing walls. The communication holes formed in the plurality of reinforcing walls are preferably arranged alternately when viewed from above. The passage of the reinforcing walls in the direction of the width of the tube is preferably up to 4 mm. A lower efficiency of heat exchange will result if the step is greater than 4 mm. The height of the reinforcing walls is preferably up to 2 mm. If the height of the wall is more than 2 mm, not only will it face difficulties in the manufacture of a compact heat exchanger, but the resistance of the air passage will also increase to result in an impaired heat exchange efficiency . The present invention will be described in greater detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view of a flat heat exchange tube produced by the process of the embodiment 1 of the invention; Figure 2 is an enlarged fragmentary cross-sectional view of the flat heat exchange tube of Figure 1; Figure 3 is an enlarged view of the section taken along line 3-3 in Figure 1; Figure 4 is a schematic diagram showing an apparatus for producing a lower member to form the tube of Figure 1; Figure 5 is an enlarged view along line 5-5 of Figure 4; Figure 6 is an enlarged fragmentary perspective view in cross section showing the development of the peripheral surface of the central roller included in the apparatus of Figure 4; Figure 7 is a cross-sectional view of the lower member for forming the tube of Figure 1; Figure 8 is an enlarged fragmentary perspective view showing how the lower component member and the upper component member are joined by the mode 1 process; Figure 9 is an enlarged perspective view of the cross section of a forging of a pre-laminated aluminum plate by a pre-rolling train of the apparatus of Figure 4; Figure 10 is a cross-sectional view showing the upper component member attached to the lower component member by the mode 1 process; Figure 11 is a perspective view showing a device for temporarily joining the upper component member to the lower component member in the modeling process; Figure 12 is a cross-sectional view of a flat heat exchange tube produced by the process of the embodiment 2 of the invention; Figure 13 is an enlarged fragmentary view of the cross section of a flat heat exchange tube of Figure 12; Figure 14 is an enlarged fragmentary perspective view showing how the upper component member and the lower component member are joined by the mode 2 process; Figure 15 is a cross-sectional view showing the upper component member attached to the lower component member by the mode 2 process; Figure 16 is a cross-sectional view of a flat heat exchange tube produced by the process of the embodiment 3 of the invention; Figure 17 is a perspective view of the cross section of a member for forming the tube of Figure 16; Figure 18 is a cross-sectional view corresponding to Figure 5 and showing a finishing rolling train for preparing the component member of Figure 17; Figure 19 is a cross-sectional view of a flat heat exchange tube produced by the process of the embodiment 4 of the invention; Figure 20 is a perspective view of the cross section of a member for forming the tube of Figure 19; Figure 21 is a cross-sectional view of a flat heat exchange tube produced by the process of the embodiment 5 of the invention; Figure 22 is a perspective view of the cross section of a member for shaping the tube of Figure 21; Figure 23 is a cross-sectional view of a flat heat exchange tube produced by the process of the embodiment 6 of the invention; Figure 24 is a perspective view of the cross section showing how to join an upper component member in a lower component member by the process of mode 6 and Figure 25 is a front view of a condenser comprising heat exchange tubes drawings of the present invention.

DESCRIPTION OF THE PREFERRED MODALITIES The modalities of the. present invention will be described below with reference to the drawings. The term "aluminum" as used in the following description includes pure aluminum and aluminum alloys. Through the diagrams, similar parts are designated with similar reference numbers and will not be described repeatedly. Figure 25 shows a condenser comprising flat heat exchange tubes incorporating the invention. The condenser comprises a pair of heads 121, 122 arranged to the right and left in parallel and spaced apart from each other, parallel flat heat exchange tubes 123 each joined at their ends opposite to the heads 121, 122, corrugated fins 124 arranged in an air flow space between the adjacent heat exchange tubes 123 and welded to the adjacent tubes 123, an inlet pipe 125 connected to the upper end of the left reed bed 121, an outlet pipe 126 connected to the lower end of the right reed bed 122 , a left partition 127 provided within the left reed 121 and connected above the middle portion thereof and a right partition 128 provided within the right reed 122 and placed below the middle portion thereof, the number of exchange tubes flat heat 123 between the inlet pipe 125 and the left partition 127, the number of heat exchange pipes 123 between the left port 127 and right partition 128 and number of heat exchange tubes 123 between right partition 128 and exit pipe 126 decreasing from above in descending order. A refrigerant flowing in the inlet pipe 125 in a vapor phase flows in zigzag through the condenser before leaving the outlet pipe 126 in a liquid phase. The flat heat exchange tubes in the foregoing condenser are those that embody the invention. Examples of flat heat exchange tubes embodying the invention will be described below. In the following embodiments, all reinforced walls have an aperture ratio of 10 to 40%, which is a percentage of the communication holes formed in the wall-based reinforcing wall. The communication holes formed in a plurality of reinforcing walls are arranged alternately when viewed from above. The article to be welded is degreased before brazing and then coated with bronze flux.

Modality 1 This embodiment is illustrated in Figure 1 to 11. The process of this embodiment produces a flat heat exchange tube A, which is shown in Figures 1 to 3, comprises flat upper and lower walls 1, 2 to which welding the fins, vertical left and right side walls 3, 4 connected between opposite lateral ends of the walls 1, 2, and a plurality of reinforcing walls 5 disposed between the side walls 3, 4, connected between the upper and lower walls 1 , 2 extending longitudinally of the tube A and separated from each other by a predetermined distance. The tube A has parallel coolant passages 6 inside it. Between the adjacent reinforcing walls 5, small projections 7 are formed which increase the transfer area on the upper surface of the lower wall 2 integrally therewith. A plurality of trapezoidal communication holes 8 are formed at the upper end of each wall 5 to effect communication between the parallel coolant passages 6. The flat heat exchange tube A comprises an upper component member 20 in the form of a flat plate and provides the upper wall 1, and a lower component member 10 of combined form in cross section having a flat portion 11 that provides the lower wall 2, right and left vertical portions 12 that provide the right and left side walls 4, 3, projections 13 that provide the reinforcing walls , and small projections 7 that increase the heat transfer area. Each vertical portion 12 of the lower component member 10 has a stepped portion 12a at the same level as the upper end of the projection 13, and a thin wall 15 extending upwardly from the stepped portion. The upper component member 20 has a slope 21 that slopes outwardly in a downward direction and that provides an upper surface in each of its opposite side portions. The upper thin wall 15 should be adjusted on the slope 21 by bending it. Each projection 13 has trapezoidal cutouts 14 that provide the communication holes 8. The flat heat exchange tube A is produced by the following process.

First, the lower component member 10 illustrated in Figures 7 and 8 is prepared using the apparatus shown in Figures 4 to 6. With reference to Figure 4, the apparatus for preparing the lower component member 10 comprises an unwinder 31 having a forge of an aluminum plate 30 (in the form of an aluminum welding plate with a layer of brazing material on the surface thereof) rolled therein with the layer of the brazing material placed towards outside, a preliminary rolling mill 32, a finishing rolling mill 33 and transport rollers 34. The. Aluminum plate 30 is extracted from the unwinder 31, which passes through the preliminary rolling mill 32, then is fed to the finishing rolling mill 33 and rolled there for finishing, whereby the lower component member 10 is prepared. As illustrated in Figure 9, the preliminary lamination train 32 causes one end of the aluminum plate 30 opposite the layer of the brazing material to project and form thick wall portions 30a on the opposite end portions of the edge. . The finishing rolling mill 33 comprises a central working roller 35, a plurality of planetary working rolls 36 arranged around a portion of the periphery of the roller 35 above and equidistantly circumferentially spaced apart from the roller 35. The planetary work rolls 36 they are disposed relative to the central working roll 35 so that the separation of the laminate gradually decreases towards the advancing direction of the aluminum plate 30. The central working roll 35 is rotated by the drive means not illustrated. The planetary work rolls 36 are rotatable in relation to the central work roll 35 by a gear device not illustrated, so that the rotation of the roller 35 rotates to all the planetary work rolls 36 with the same peripheral speed as the roll 35. The finishing rolling train 33 additionally has a trapezoidal guide shoe 37 between each pair of planetary work rolls 36 immediately adjacent, and springs 38 for centering the guide shoe 37 towards the central work roll 35. Each of the leading and trailing edges of the guide shoe 37 extends into the space between the roller 35 and the roller 36 to such an extent that the shoe does not come into contact with these rollers. The guide shoe 37 suppresses the longitudinal elongation of the aluminum plate 30 while it passes through the train 33, further inhibiting the plate from bulging outwardly between the adjacent planetary work rolls 36. The longitudinal elongation of the plate 30 it is also suppressed by rotating all the planetary rollers 36 with the same peripheral speed as the central roller 35. Since the longitudinal elongation of the aluminum plate 30 is suppressed, the plate can be of a thickness smaller than the aluminum plate conventionally used. . This decreases the cost of material, and the rolling reduction may be less than in the prior art. With reference to Figures 5 and 6, the central working roll 35 of the finishing rolling train 33 is formed on its parallel surface with parallel annular grooves 39, 40 which are equal in depth, and trapezoidal projections 43 which are formed to a predetermined interval in each of the annular grooves 40 other than the annular grooves 43 at opposite ends, the projections 43 having a height less than the depth of the grooves 40. The annular groove 39 at each of the opposite ends has a greater width that the other grooves 40 and is further formed with an annular groove 41 of little width at the outer edge of its base. The parallel shallow annular grooves 42 are further formed in the roller 35 between each pair of immediately adjacent annular grooves 30, 40. The aluminum plate 30 shown in Figure 9 and formed with thick wall side portions 30a and a portion of thin wall 30b therebetween is laminated by passing it between the central working roll 35 and the planetary work rolls 36. As illustrated in Figure 7, the rolling operation thins the plate 30 to a predetermined thickness forming a flat portion 11 providing the lower wall 2 and causes the annular grooves 39, 40 to form vertical portions 12 providing the right and left side walls 3, 4 and vertical projections 13 providing the reinforcing walls 5, these portions 12, 13 projecting from the flat portion integral with the same. In addition, the projections 43 in each slot 40 form trapezoidal cutouts 14 at the upper end of the projection 13 at a predetermined interval, and the grooves 42 form projections 7 that increase the heat transfer area by projecting similarly from the flat portion 11. integrally with it. The annular grooves 41 of small width are formed in the upper portions of the vertical portions 12 of greater thickness than the projection 13, stepped portions 12a at the same level as the upper ends of the projections 13 and a thin ascending wall 15 extending from each stepped part 12a. It is now assumed that the lower component member 10 shown in Figure 7 and to be prepared is 18 mm in overall width, 0.35 mm in thickness of the wall T of the flat portion 11, 1 mm in height H of the vertical portions 12 , 1.4 mm in the thickness TI of the same, 0.65 mm in height Hl of the ascending side walls 15, 0.4 mm in the thickness of T2 of the same, 1 mm in the height H2 of the projections 13, 0.4 mm in the thickness of T3 thereof, 0.8 mm in step P of the projections 13, 0.2 mm in the height H3 of the projections 7 and 0.2 mm in the thickness T4 of the same. In this case, suppose that the aluminum plate 30 shown in Figure 9 has in width, wl in the width of the thick wall portions 30a, t in the thickness of the thin wall portion 30b and ti in the thickness of the 30a thick wall portions. The lower component member 10 can then be prepared with the above design dimensions when w = 18 mm, wl = 1.34 mm, t = 0.57 mm and ti = 1.13 mm, when w = 18 mm, wl = 1.49 mm, t = 0.62 mm and tl = 1.19 mm, when w = 18 mm, wl = 1.63 mm, t = 0.68 mm and t = 1.25 mm. The forge of the aluminum plate 30 of Figure 9 has the thick wall portions 30a that are formed causing one end of the forge opposite the layer of welded material to project, while the end of the layer of welded material can causing it to project in the opposite manner, or it may be caused that both ends are projected to form the thick portions. Separated from the lower component member 10, the upper component member 20 is prepared from a flat aluminum plate having the shape of an aluminum welding plate covered with a plate of brazing material on opposite ends thereof and which it is formed with a slope 21 that descends outwardly downward on the surface of each edge portion thereof (see Figure 8). The upper member 20 is temporarily attached to the lower member 10 by placing each edge portion of the upper member 20 in the stepped portion of the vertical portion 12 of the lower member 10, bending inward the rising thin wall 15 of each vertical portion 12 and thus adjusting intimately the wall 15 on the slope 21 of the upper member 20. This operation is performed continuously using a device comprising pairs of upper and lower forming rollers 80 for bending the thin walls 15, and pairs of upper and lower drive rollers 81 for coupling the upper and lower component members 20, 10 from above and below as seen in Figure 11. Subsequently, the temporarily secured assembly is cut to specific lengths by a shear to obtain the intermediate products of the heat exchange tubes. The assembly is therefore cut in the direction of the height of the product, that is from above or from below. This prevents the vertical portions w and the projections 13 from being deformed. These portions are prone to deform if the assembly is cut by the width of the product, i.e. from the right or the left. Such intermediate products of the heat exchange tubes are collectively welded in combination with the heads and fins. By this method, the upper member 20 placed on the projections 13 is provided to provide the upper wall 1 of the flat heat exchange tube A, the thin upwardly bent walls 15 of the upper member 20 are welded to the stepped portions of the portions respective verticals 12 of the lower member 10 to achieve vertical portions 12 serve as the right and left side walls 4, 3, the projections 13 of the lower wall 2 are welded to the upper wall 1 to form the reinforcing walls 5, and the openings of the trapezoidal cutouts 14 in the projections 13 are closed with the top wall 1 to thereby form the trapezoidal communication holes 8 to hold the parallel passages of the coolant 6 in communication with each other. In this way the flat heat exchange tube A is obtained. The assembly of the upper and lower members 20, 10 as temporarily secured can be temporarily joined by a high frequency brazing before the above welding procedure.

Alternatively, the upper and lower members 20, 10 as they temporarily joined together can be welded to obtain a finished product from the heat exchange tube. The heads and fins can then be welded to such tubes to assemble a heat exchanger.

Mode 2 This embodiment is shown in Figures 12 to 15. The process of this embodiment provides a flat heat exchange tube Al having the same construction as the tube provided by mode 1 except that the right and left side walls 51, 50 present a double structure as seen in Figures 12 and 13. The flat heat exchange tube Al comprising a lower component member 60 and an upper component member 70, have the same construction as the tube of the modality 1 with the exception of the following characteristics. The lower component member 60 has the right and left vertical portions 61 having the same height and thickness as the projection 5 and is formed in each lower edge portion of a flat portion 11 with a slope 62 that slopes outwardly and upwardly. . The upper member 70 is formed at each Lateral edge thereof, by a dependent portion 72 having approximately the same thickness as the vertical portion 61 and tapered downwards and inwards in the cross section at its lower end so that the lower end it can be adjusted on slope 62 by folding it. The upper member 70 has a width such that the dependent portions 72 can be adjusted to the respective vertical portions 61 of the lower member 60 from the outside. The Al tube is prepared by the following process. The lower component member 60 is formed first using the same apparatus shown in Figures 4 and 5 as was used to practice the modality 1 process with the exception of the following (see Figure 14). The apparatus of the present embodiment is not provided with the preliminary lamination train 32. Consequently, a flat aluminum plate forge in the form of a brazing plate having a layer of brazing material on one side thereof is fed to the finishing rolling mill 33. The central working roller 35 of the finishing rolling mill 33 is formed on its peripheral wall with parallel annular grooves which are equal in width and depth except that only the annular grooves at opposite ends have each of them a basal face connected to an external lateral face by means of an inclination.

Separated from the lower component means 60, the upper component member 70 is prepared from an aluminum plate having the form of an aluminum welding plate covered with a layer of brazing material at opposite ends thereof and having 72 dependent portions on their opposite lateral edges. The dependent portions 72 have a slightly greater height than the vertical portions 61 and each of them has a lower end 73 tapered downwards and inwards in cross section. Subsequently, the upper member 70 fits over the lower member 60, and the lower ends 73 of the dependent portions 72 of the upper member 70 are bent inwardly and thus intimately conform to the slopes 62 of the lower member 60, thereby two members 60, 70 join temporarily. The same procedure that is carried out in mode 1 is then carried out to obtain a flat heat exchange tube Al.

Mode 3 This embodiment is illustrated in Figures 16 to 18. As shown in Figure 16, the process of this embodiment produces a flat heat exchange tube A2, comprising flat upand lower walls 86, 87 to which they must be welded. the fins, left and right side walls 85, 88, each having an outer circular arc surface and connected between the opposite side edges of the walls 86, 87 and a plurality of reinforcing walls 89 disposed between the side walls 85 , 88, connected between the upand lower walls 86, 87, extending longitudinally of the tube A2 and separated from each other by a predetermined distance. The tube A2 has parallel passages of coolant 74 therein. Each reinforcing wall 89 is formed in the middle portion of its height with hexagonal communication holes 90 to support the parallel passages of coolant 74 in communication with each other. The tube A2 is formed by a single component member 94. As seen in Figure 17, the component member 94 comprises a central planar portion 92 positioned at half its width and providing the right side wall 88; A right flat portion 91 providing the upwall 86, projections 89a providing the uphalves of the reinforcing walls 89 and a circular arc portion 85a providing the uphalf of the left side wall 85, the portions 91, 89a and 85a being positioned to the right side of the central flat portion 92; and a left flat portion 93 providing the bottom wall 87, projections 89b providing the reinforcing wall halves 89 and a circular arc portion 85b providing the lower half of the left side wall 85, the portions 93, 89b and 85b being positioned at left side of the central flat portion 92. Each of the projections 89a (89b) has trapezoidal cutouts 90a (90b) to form the uphalves (lower halves) of the communication holes 90. The flat heat exchange tube A2 is Prepare by means of the following procedure. First, the upcomponent 94 is prepared using the same apparatus as shown in Figures 4 and 5 and as used to preict the mode 1 process. The apparatus for the present embodiment is not provided with a preliminary rolling mill 32 Accordingly, a forge of an aluminum plate is fed in the form of a welding plate having a layer of brazing material on one side thereof to the finishing rolling train 33. As shown in Figure 18 , the central working roll 35 of the finishing rolling mill 33 is shaped at its phery with parallel annular grooves 97 at opposite ends of the middle portion of its length symmetrically, and the projections 99 are formed having a height less than the depth of the grooves at predetermined intervals in each of the annular grooves 97. To the right of the right annular groove 97 that is further out, the roller 35 has an annular groove 9. 5 of the right end greater than the slot 97 in depth and width and defined by a basal face and a vertical internal side face connected thereto by a slope. To the left of the left annular groove 97 that is further out, the roller 35 has a left end annular groove 95 greater than the groove 97 in terms of depth and width and having an inclined basal face, the upend of which is connected to the vertical external lateral face by a stepped portion. The planetary work roll 36 is provided at its right end with a right flange 98a having a phery in contact with the basal side of the right end slot 95 and at the left end thereof with a left flange 98b having a phery in contact with the stepped portion of the left end slot 96. The flanges 98a, 98b each have an inner face bent inwardly. A forge of an aluminum plate 30 is laminated by the train 33 comprising a central working roll 35 and the planetary working rolls 36 for thinning the forge 30 to a predetermined wall wall thickness with the peripheral surface of the work roll. central 35 and that of the planetary work rolls 35 to form a central planar portion 92, a right planar portion 91 and a left planar portion 93, caused the parallel annular grooves 97 to form projections 89a, 89b projecting from the planar portions 91, 93 integrally therewith, causing the projections 99 in the slots 97 to form trapezoidal cutouts 90a, 90b at the predetermined interval at the upper edges of the projections 89a, 89b and bending the opposite lateral edges of the forge in the projection direction of the projection 89a, 89b to form the circular arc portions 85a, 85b. The resulting laminated aluminum forge having cutouts 90a, 90b in the projections 89a, 89b for example the component member 94, is bent in the middle portion of its width like a fork to obtain a right side wall 88. The side edges are welded butt to each other for joining the upper and lower circular arc portions 85a, 85b and forming a left side wall 85. The descending projections 89a are welded to the rising projections 89b to form the reinforcing walls 89 with the cutouts 90a, 90b, combined to form the hexagonal communication holes 90 in the middle portions of the walls 89 to hold the parallel passages of refrigerants 74 in communication with each other. In this way, a flat heat exchange tube A2 is obtained.

Modality 4 This mode is illustrated in Figures 19 and 20. The modeling process produces a flat heat exchange tube A3, which as shown in Figure 19, has the same construction as the modality 1 tube except that reinforcing walls 100 each have trapezoidal communication holes 101 at the upper end and reinforcing walls 100 each have trapezoidal communication holes 101 at the upper end and reinforcing walls 100 having similar holes 101 at the lower end are arranged alternately. The tube A3 is formed by a single component member 102. As illustrated in Figure 20, the component member 102 comprises a central planar portion 92 in the middle portion of its width to provide a right side wall 88, a right flat portion 91. providing an upper wall 86, projections 100a that provide the reinforcing walls 100 and a circular arc portion 85a that provides the upper half of a left side wall 85 that is positioned on the right side of the central planar portion 92; and a left flat portion 93 that provides a lower wall 87, projection 100b that provides the other reinforcing walls 100 and a circular arc portion 85b that provides the other half of the left side wall 85 that is placed on the left side of the central planar portion 92. The projections 100a, 100b have respective trapezoidal cutouts 101a, 101b that provide the communication holes 90. The projections 100a in the right planar portion 91 are smaller by one in number than the projections 100b in the left planar portion 93. , and they are displaced towards the right lateral edge of the component member 102 relative to the last projections by 1/2 of the passage of the projection. The tube A3 is produced in the same way as the tube of the modality 3 with the exception of the following characteristic of the central working roller. Although the center work roll is formed by parallel annular grooves at the opposite ends of the middle portion of its length, the grooves on the right side are displaced from the grooves on the left side by 1/2 of the groove passage towards the groove. end of the right roller, and they are smaller by one in number than the slots on the left. The annular grooves have twice the depth of the annular grooves of the embodiment 3. Using a central working roller, a laminated aluminum plate is obtained, for example the component member 102, having cutouts 101a, 101b in the respective projections 100a, 100b. The right side wall 8 is formed by bending the member 102 in the middle portion of its width like a fork, the left side wall 85 is formed by butt welding the opposite side edges and thus joining the circular arc portions 85a, 85b, the reinforcing walls 100 are formed by welding the projection 100a of the upper wall 86 to the flat portion of the lower wall 87 and the projections 100b of the lower wall 87 to the flat portion of the upper wall 86 alternately, and the openings of the walls. cutouts 101a, 101b on the projections 100a, 100b are closed with the flat portion to form the trapezoidal communication holes 101 in the parallel reinforcing walls 100 in upper and lower positions alternately to hold the parallel passages of coolant 74 in communication with each other.

Modality 5 This embodiment is illustrated in Figures 21 and 22. The process of this embodiment produces a flat heat exchange tube A4, which has the same construction as the modality 1 tube except that the trapezoidal communication holes 106 are formed in the lower ends of the reinforcing walls 105 as shown in Figure 21.

The tube A4 is formed by a single component member 107. As seen in Figure 22, the component member 107 comprises a central planar portion 92 in the middle portion of its width to provide a right side wall 88.; a right flat portion 91 providing an upper wall 86, projections 106a for providing the reinforcing walls 105 and a circular arc portion 85a for providing the upper half of a left side wall 85 that are positioned on the right side of the central planar portion 92; and a left flat portion 93 that provides a lower wall 87 and a circular arc portion 85b that provides the lower half of the left side wall 85 that are positioned on the left side of the central planar portion 92. The projection 105a has trapezoidal cutouts 106a provided by communication ports 106. The flat heat exchange tube A4 is produced in the same manner as the tube of mode 3 with the exception of the following characteristic of the central working roller. The central trickle roller has parallel annular grooves only on the right side of the middle portion of its length and the annular grooves have twice the depth of the annular grooves of mode 3. The tube A4 is prepared from a plate laminated aluminum, for example the component member 10.7, obtained using a central working roll having cutouts 106a in the projections 105a, bending the member 107 in the middle portion of its width like a fork to form a right side wall 88 and welding butt the opposite lateral edges, joining the upper and lower circular arc portions 85a, 85b to form a left side wall 85, by welding the projection 105a- of an upper wall 86 to the flat portion of a lower wall 87 to form walls of reinforcement 105 and closing the openings of the trapezoidal cutouts 106a in the projection 105a with the flat portion to form the trapezoidal communication holes 106 at the lower ends of the walls 105 to hold the parallel passages of coolant 74 in communication with each other.

Modality 6 This embodiment is shown in Figures 23 and 24. The process of the embodiment produces a flat heat exchange tube A5 having the same construction as the modality 1 tube except that the tube A5 has a right side wall 110 with a outer surface of circular arc and a vertical inner surface as shown in Figure 23.

As shown in Figure 24, the flat heat exchange tube A5 is formed by two upper and lower component members 112, 114. More specifically, the upper member 112 comprises a flat portion 111 that provides an upper wall 86, descending projections 89a which provide the upper halves of the reinforcing walls 89 and portions 85a, 110a having a circular outer face and providing the upper halves of the opposite side walls 85, 110. The lower member 114 comprises a flat portion 93 which provides a lower wall 87, rising projections 89a which provide the lower halves of the walls 89 and portions 85b, 110b having an outer circular arc surface and providing the lower halves of the side walls 85, 110. The projections 89a, 89b have cutouts respective trapezoidal 90a, 90b which provide the upper halves and the lower halves of the communication holes ation 90. The flat heat exchange tube A5 is produced by the following process. First, the upper and lower component members 112, 114 are prepared using two apparatuses that are the same as those used to practice the modality 1 process and are shown in Figures 4 and 5.

In this case, the central work roll 35 and the planetary work roll 36 of the finishing laminate train 33 of one of the apparatuses have such a cross section that with reference to Figure 18, the right end slot 95 of the roller central 35 and flange 98a of planetary roller 36 are respectively the same as the slots of the left end 96 of the first and the flange 98b of the latter in symmetry at opposite ends, only with half portions of the parallel annular grooves formed between the end slots opposite. The central work roll 35 and the planetary work roll 36 of the finishing rolling mill 33 of the other apparatus have such cross section that with reference to the same drawing, the left end slot 96 of the central roller 35 and the flange 98b d planetary roller 36 are respectively the same as the right end groove 95 of the first and flange 98a of the latter in symmetry to opposite ends, only with middle portions of the parallel annular grooves formed between the opposite end grooves. Aluminum forgings are laminated comprising a welding sheet having a layer of brazing material on opposite surfaces by the two rolling mills to thin the forges to a specific thickness and form flat portions 111, 113, causing the annular grooves forming the projecting projections 89a, 89b, of the flat portions 111, 113 integrally therewith, causing the projections within the grooves to form trapezoidal cutouts 90a, 90b at a predetermined interval at the upper edges of the projections 89a, 89b and by folding the opposite lateral edges in the direction of projection of the projections 89a, 89b to form the portions 85a, 110a, 85b, 110b each having an outer circular arc face. The two laminated aluminum sheets obtained, that is to say, the upper and lower component members 112, 114, are butted together opposite each other at the edges of each side, the upper and lower portions 85a, 110a, 85b, 110b having a each circular arc exterior are joined to obtain the opposite side walls, with the flat portions 111, 113 of the upper and lower component members 112, Serving as upper and lower walls 86, 87 and the descendant projections 89a are welded to the ascending projections 89b to form the reinforcing walls 89, with the cutting portions 90a, 90b of the projections 89a, 89b combined to form the holes hexagonal communication means 90a in the middle portion of the height of the reinforcing walls 89 to cause the parallel passages of coolant 74 to communicate with each other therethrough. In this way, a flat heat exchange tube A5 is prepared.

The upper walls of the flat heat exchange tubes of the modes 1 and 2, the upper and lower walls of the tubes of Modes 3 to 6 can be formed with low projections that increase the heat transfer area as in the case of the lower wall of the Modality 1. According to the preceding embodiments, the central working roll of the finishing rolling mill has several annular grooves, while such annular grooves may be formed alternately on the planetary working rolls. In all the foregoing embodiments, cutouts are formed in the projections simultaneously when the forging of the aluminum sheet passes through the finishing rolling mill, although the cuttings may be formed separately after the forging has passed through the cutting train. laminate. In this case, the projections do not need to be formed on the basal face defining the annular groove of the central working roller.

Claims (18)

1. A process for producing a flat heat exchange tube having parallel coolant passages therein and characterized in that it comprises flat upper and lower walls to which fins will be attached, and a plurality of reinforcing walls connected between the upper and lower walls. , which extend longitudinally of the tube and are separated from each other by a predetermined distance, using a rolling train comprising a central working roller and a plurality of planetary working rolls arranged around a portion of the periphery of the central working roller and separated circumferentially from each other, the central working roller or the planetary work rolls with parallel annular grooves in the periphery of the roller being formed, the rolling process comprising a forging of a metal sheet by a rolling train and thereby reducing the thickness of the forge to a specific value, with the peripheral surface of the central work roll and the peripheral surfaces of the planetary work rolls to form a flat portion serving at least an upper wall and a lower wall and form vertical projections projecting from the planar portion integrally therewith and provide the reinforcing walls with the annular grooves.

2. A process for producing a flat heat exchange tube according to claim 1, characterized in that the rolling train further comprises a guide shoe between each pair of immediately adjacent planetary working rolls and means for centering the guide shoe towards the roller. central work.

3. A process for producing a flat heat exchange tube according to claim 1, characterized in that a roller formed with parallel annular grooves and shallow annular grooves parallel between each two adjacent annular grooves is used as a central working roller or as each of the planetary work rolls to form low protrusions that increase the transfer area projecting from the planar portion integrally therewith as the vertical protrusions projecting from the planar portion integrally therewith and which provide the reinforcing walls with the annular grooves.

4. A process for producing a flat heat exchange tube according to claim. 1, characterized in that a roller formed with parallel annular grooves and projections provided at a predetermined interval in each of the grooves and having a height less than the depth of the groove as the central working roller or as each of the planetary rollers, so that when the vertical projections projecting from the flat portion are formed integrally with it and provide the reinforcing walls with the annular grooves , a plurality of trimming is formed at the predetermined interval at the upper edge of each of the projections to form the communication holes for effecting communication between the parallel refrigerant passages.

5. A process for producing a flat heat exchange tube according to claim 4, characterized in that the cutouts are trapezoidal.

6. A process for producing a flat heat exchange tube in accordance with claim 4, character! because each of the reinforcing walls has an opening ratio of 10 to 40% which is the ratio of all communication holes in the reinforcing walls to the reinforcing wall.

7. A process for producing a flat heat exchange tube according to claim 4, characterized in that the communication holes in the plurality of the reinforcing walls are arranged alternately when viewed from above.

8. A process to produce a flat heat exchange tube that has parallel passages of refrigerant inside it, characterized in that it comprises upper and lower flat walls to which fins, opposite side walls and a plurality of reinforcing walls connected between the upper and lower walls, extending longitudinally of the tube and separated from each other by a predetermined distance, are connected, using a rolling train comprising a central locking roller and a plurality of planetary working rolls arranged around a portion of the periphery of the central working roller and circumferentially spaced therefrom, with the central working roller or the working rolls being formed planetary with parallel annular grooves in the periphery of the roller and projections provided at a predetermined interval in each of the annular grooves other than the annular grooves in the opposite laminate ends and having a height less than the depth of the grooves, comprising the process the rolling stage by the train of a forge of a sheet of metal having a greater thickness than the bottom wall of the heat exchange tube that will be produced and thus reducing the thickness of the forge to the specific value with the peripheral surface of the central working roll and the peripheral surfaces of the planetary work rolls to form a flat portion that serves as the bottom wall, causing the annular grooves at the ends of the roll to form vertical portions that provide the respective side walls and the other annular grooves to form vertical projections that provide the walls of the walls. reinforcement, the vertical portions and the vertical projections projecting from the planar portion integrally therewith and causing the projections in each slot to form cutouts on the upper edge of each of the projections at the predetermined interval, and the step of placing the metal sheet over the paia protrusions provide the top wall, joining the metal sheet with the vertical portions to achieve that the vertical portions serve as the opposite side walls, joining the projections of the lower wall with the upper wall to form the reinforcing walls and closing the openings of the cut-outs in each of the protrusions with the top wall to form communication holes to hold the parallel passages of coolant and communication with each other.

9. A process for producing a flat heat exchange tube according to claim 8, characterized in that the annular grooves at the ends of the roller have a greater width than the other annular grooves and each of them is additionally formed at the outer end of the groove. the base thereof with an annular groove of reduced width, the forging of the metal sheet having a thick portion at each of the opposite lateral edges thereof to thereby provide a greater thickness to the vertical portion than the projections and form a part thereof. staggered at the same level as the upper ends of the projections to an upper portion of each vertical portion and a thin wall projecting upwards from the stepped portion, the sheet metal being flat and having a downward slope outwardly on the upper surface of each of the portions of the edge of the same, with each of the lateral edge portions of the leaf being placed. a metal in the stepped portion of the vertical portion, followed by the joining of the thin wall ascending the vertical portion to the slope of the metal sheet by bending inward the thin wall and adjusting the thin wall to the slopes.

10. A process for producing a flat heat exchange tube according to claim 9, characterized in that the metal sheet has an integral slope portion with each of the side edge portions thereof, and the opposite side walls are formed adjusting the portions of slopes to the respective vertical portions of the bottom wall at the outer end thereof to form a flat metal tube.

11. A process for producing a flat heat exchange tube according to claim 10, characterized in that when the flat portion provided by the bottom wall is formed by the laminate of the forge of the metal sheet, an upwardly sloping slope is formed. in each of the lower lateral edge portions thereof, and the slope portion is given a slightly greater height than the vertical portion and has a lower end portion tapered downward and inward in cross section to fit and join the portion tapered to the slope.

12. A process for producing a flat heat exchange tube having parallel passages of coolant therein and characterized in that it comprises flat upper and lower walls to which fins will be attached, and a plurality of reinforcing walls connected between the upper and lower walls. , which extend longitudinally of the tube and are separated from each other by a predetermined distance, using a rolling train comprising a central working roller and a plurality of planetary working rolls arranged around a portion of the periphery of the central working roller and circumferentially spaced apart therefrom, the working roller or planetary work rolls being formed at the periphery of the roller with parallel annular grooves at opposite ends of the middle portion of the length thereof symmetrically, projections being formed at a predetermined interval in each of the annular grooves and that have a a height less than the depth of the grooves, the process comprising the step of rolling a sheet metal forging by the rolling mill having a thickness greater than the wall thickness of the heat exchange tube that will be produced and reduced with it the thickness of the forge at a specific pipe wall thickness with the peripheral surface of the central working roll and the peripheral surfaces of the planetary work rolls to form a flat portion, causing the annular grooves to form protrusions projecting of the flat portion integrally with it, causing the projections in each slot to form cutouts in the upper edge, each of the projections, at the predetermined interval and bending at least one of the opposite lateral edges of the forging towards the direction of projection of the projections and the step of bending the resulting metal sheet having the cutouts in the projections as a fork in the middle portion of the width of the plate, butt welding on the side edges of the plate, joining the downward projections with the upward projections to form the reinforcing walls and combining the cutouts of the opposing shoulders to form the holes of communication to hold the parallel passages of refrigerant in communication with each other.

13. A process for producing a flat heat exchange tube having parallel passages of coolant therein and characterized in that it comprises flat upper and lower walls to which fins will be attached, and a plurality of reinforcing walls connected between the upper and lower walls. , extending longitudinally of the tube and spaced apart by a predetermined distance, using a rolling train comprising a central working roller and a plurality of planetary working rolls arranged around a portion of the periphery of the central working roller and circumferentially spaced apart of the same, the central working roller or the planetary work rolls being formed at the periphery of the roller with parallel annular grooves at each of the opposite ends of the middle portion of the same length, the annular grooves of one of the ends being displaced. the opposite ends of the annular grooves in the other xtreme by 1/2 of the passage of the groove toward one end of the roller, and the projections being formed at a predetermined interval in each of the annular grooves and having a height less than the depth of the grooves, the process comprising the step of laminating with the rolling mill a forge of a metal sheet having a thickness greater than the wall thickness of the heat exchange tube that will be produced and thus reducing the thickness of the forge to a specific tube wall thickness with the peripheral surface of the central work roll and the oeripheral surfaces of the planetary work rolls to form a flat portion, causing the annular grooves to form protrusions projecting from the flat portion integrally therewith, causing the projections in each The grooves form cutouts on the upper edges of each of the protrusions at a predetermined interval and bending at least one of the lat borders. opposite sides of the forging towards the projection direction of the projections, and the step of bending the resulting sheet of metal having the cutouts in the projections as a fork in the middle portion of the width of the plate, butt-welding them. lateral edges of the plate, joining the projections on the resulting upper wall with the flat portion of the resulting lower wall and the projections of the lower wall with the flat portion of the upper wall alternately to form the reinforcing walls and closing the openings of the cutouts in the projections with the flat portions to form communication holes to hold the parallel passages of refrigerant in communication with each other.

14. A process for producing a flat heat exchange tube having parallel passages of refrigerants therein and characterized in that it comprises upper and lower flat walls to which fins will be attached, and a plurality of reinforcing walls connected between the upper and lower walls. , extending longitudinally of the tube and spaced apart by a predetermined distance, using a rolling train comprising a central working roller and a plurality of planetary working rolls arranged around a portion of the wall of the periphery of the central working roller and circumferentially spaced apart therefrom, the central working roller or the planetary working rolls being formed at the periphery of the roller with parallel annular grooves at one of the opposite ends of the middle portion of the length thereof, with projections being formed at an interval predetermined in each of the annular slots and which e have a height less than the depth of the grooves, the process comprising the step of rolling a sheet metal forging by a rolling mill having a thickness greater than the thickness of the wall of the heat exchange tube that is will produce, and thus reduce the thickness of the forge to a specific tube wall thickness with the peripheral surface of the central working tube and the peripheral surfaces of the planetary work rolls to form a flat portion, causing the annular grooves to project projections from the planar portion integrally therewith, causing the projections in each groove to form cutouts in the upper edge of each of the projections at predetermined interval and bending at least one of the projections. opposite lateral edges of the forging towards the direction of projection of the projections, and the step of bending the resulting sheet of metal having the cutouts in the projections as a fork in the middle portion of the width of the plate, butting to butt the side edges of the plate, joining the projections on one of the upper and lower walls resulting with the flat portion of the other wall to form the reinforcing walls and closing the opening of the cutouts of the projections with the flat portion for forming the communication holes to hold the parallel passages of refrigerant in communication with each other.

15. A process for producing a flat heat exchange tube in the form of a flat metal tube having parallel passages of coolant therein and characterized in that it comprises flat upper and lower walls to which fins will be attached, and a plurality of walls reinforcing elements connected in: the upper and lower walls, extending longitudinally of the tube and separated from each other by a predetermined distance, using a rolling train comprising a central working roller and a plurality of planetary working rolls arranged around a portion from the periphery of the central working roller and circumferentially spaced from it, the central working roller or the planetary working rolls with parallel annular grooves being formed at the periphery of the roller, with projections being formed at a predetermined interval in each of the grooves annular and that have a height less than the depth of the slots, the process comprising the step of laminating for each of the rolling mills a forge of a sheet of metal having a thickness greater than the thickness of the wall of the heat exchange pipe that will be produced and thereby reducing the thickness The former forges a specific tube wall thickness with the peripheral surface of the central work roll and the peripheral surfaces of the planetary work rolls to form a flat portion, causing the annular grooves to project projections from the portion plane integrally therewith, causing the projections in each slot to form cutouts on the upper edge of each of the projections at a predetermined interval and bending the opposite side edges of the forging towards the projection direction of the projections, and stage of joining the two resulting sheets of metal opposite each other at the side edges to obtain the side walls, make the flat portions of the two metal sheets serve as upper and lower walls, and join the descending projections to the ascending projections thus forming reinforcing walls, and combine the cutouts of the opposed projections to form communication holes to support the parallel passages of refrigerant and communication with each other.

16. A process for producing a flat heat exchange tube according to any of claims 1 to 15, characterized in that the plurality of planetary work rolls are disposed relative to the central work roll so that the separation of laminates gradually decreases towards the Forward direction of the forging of the metal sheet.

17. A process for producing a flat heat exchange tube according to any of claims 1 to 15, characterized in that the forging of the metal sheet comprises a brazing sheet having a layer of brazing metal on at least one one of the opposite surfaces of it.

18. A process for producing a flat heat exchange tube according to any of claims 8, 9, 10, 11 or 15, characterized in that the metal sheet comprises a brazing sheet having a layer of brazing material on it. at least one of the opposite surfaces thereof. SUMMARY A pioreso for producing a flat heat exchange tube, having parallel passages of coolant therein and comprising flat upper and lower walls, opposite side walls and a plurality of reinforcing walls connected between the upper and lower walls, which they extend longitudinally of the tube and separated therefrom by a predetermined distance, using a rolling train comprising a central working roller and a plurality of planetary working rolls arranged around a portion of the periphery of the central working roller and circumferentially spaced of the same, the central work roll being formed with parallel annular grooves in the periphery thereof. A forge of an aluminum sheet comprising a brazing sheet is laminated by the rolling train and thereby thinned to a predetermined thickness to form a flat portion that serves as the bottom wall, causing the annular grooves at the ends of opposite laminate, forming vertical portions that provide the respective side walls and the other annular grooves form the vertical projections provided by the reinforcing walls, the vertical portions and the vertical projections of the planar portion projecting integrally therewith. An aluminum sheet comprising a brazing sheet that is placed over all the projections to provide the top wall and joins with the vertical portions to make the vertical portions serve as the opposite side walls, and the projections of the bottom wall , join with the upper wall to form the reinforcing walls.