SERPENTINE HEAT EXCHANGER

Abstract: A method for building a serpentine heat exchanger, particularly a condenser for refrigerating circuits being profiled in such a way to present from a lateral side view and relative to at least one part of its length an inclination the direction of which is suddenly or progressively inverted at least once relative to a plane which is substantially parallel to one of the directions defined by the extension of the exchanger (3), in particular relative to a plane substantially parallel to the principal direction of a flow of air in which the exchanger (3) is located, and in special manner relative to a substantially vertical or substantially horizontal plane. According to the invention, the method comprises the following steps: a) the construction at least of the serpentine or of the complete exchanger in a flat configuration; b) the bending and/or moulding, or deforming of the flat serpentine or of the flat complete exchanger in a way to assume the desired inclinations.

Description: Serpentine Heat Exchanger Method for building a serpentine heat exchanger particularly a condenser for refrigerating circuits and serpentine exchanger according to the said method. The invention refers to a method for building a. serpentine heat exchanger, particularly a condenser for refrigerating circuits being profiled in such a way to present from a lateral side view and relative to at least one part of its length an inclination the direction of which is suddenly or progressively inverted at least once relative to a plane which is substantially parallel to one of the directions defined by the extension of the exchanger, in particular relative to a plane substantially parallel to the principal direction of a flow of air in which the exchanger is located, and in special manner relative to a substantially vertical or substantially horizontal plane. Such kind of exchanger or condenser are known and normally they show an undulated or a "zigzag" profile. Prom the functional point of view this kind of exchanger ensure a great improvement of the thermal exchange. Such kind of exchanger make it possible to increase the surface for thermal exchange or to increase the length of the serpentine, while maintaining their overall dimensions between certain limits. Furthermore / the particular non-flat profile of the exchanger causes turbulences in the air flow along the exchanger thus increasing the efficiency of the thermal exchange. On the other hand however, the manufacture of the said undulated or zigzag exchangers is not as simple as for the usual plane exchangers and the lines for building the usual plane exchangers can be hardly used to build undulated or zigzag profiled exchangers without any alteration for adaptation to the new product. Thus for the production of undulated or zigzag exchangers special lines are needed so that the costs of production rise compared to the production of usual plane exchangers. An object of the present invention is to create a method for building a heat exchanger of the kind mentioned above, with which it is possible to avoid the aforementioned disadvantage and which ensures a low cost production of undulated and/or zigzag profiled exchangers of better quality. The present invention achieves the before mentioned aim with a method for building exchangers of the kind mentioned at the beginning, which method comprises the following steps: a) the construction at least of the serpentine or of the complete exchanger in a flat configuration; b) the bending and/or moulding, or deforming of the flat serpentine or of the flat complete exchanger in a way to assume the desired inclinations. The bending, moulding, deforming may be made in several ways, using bending machines or utensils, dies, or other deforming tools. Every kind of exchanger can be constructed by using the method according to the invention. According to a preferred embodiment the exchanger is of the kind showing at least one serpentine on every side of which wires are fitted to the serpentine, in particularly soldered to the serpentine. In this case, the method according to the invention provides that the wires on the opposite sides of the serpentine are placed staggered one with respect to the other. Thanks to this feature, the wires on the opposite sides of the serpentine do not interfere with one another during the step of bending the exchanger. A further improvement of the method according to the invention refers to the fact that the bending lines, of the exchanger in order to ensure the at least two different inclinations in opposite direction one to the other takes place at least along lines in the vicinity of and parallel to pipe segments of the serpentine, preferably along or coaxial to the said pipe segments. In this case, the pipe of the serpentine, at the bending lines, i.e. the lines at which the direction of the inclined parts suddenly or progressively changes, are subject only to a torsion substantially around its own axis, and not to a bending along a transversal axis, which normally leads to a weakening of the serpentine and to the reduction of the cross section of the pipe due to throttling of the pipe at the bending or deformation points. The particulary choice of the position of the lines of bending and the staggered wires allows the deformation of the exchanger from the flat configuration into the one showing at least some inclined sections avoiding any risk of tearing away the wires from the serpentine, i.e. breaking the point of soldering. The above mentioned advantages are particularly relevant in the case of a zigzag profiled exchanger, in which there are different bending lines. The invention refers also to a exchanger of the kind mentioned at the beginning which is characterised in that the bending lines of the different inclined sections are provided in the vicinity or alone? sections of the serpentine pipe which are parallel or coaxial to the said bending lines. Further the exchanger shows wires on the opposite sides of the serpentine which are positioned staggered the ones in respect to the other. The profile of the exchanger according to the invention can assume any or irregular shape of a broken line. For example the exchanger can show a regular zigzag profile or the profile of one or more successive saw tooth, or a combination of the above mentioned profiles, being every bending line provided in the vicinity or along a section of serpentine pipe which is parallel to the bending lines. Further features of the invention are subject of the sublcairns. The characteristic features of the invention and the advantages due to them will appear more clearly from the following description of a preferred embodiment which is illustrated in the annexed drawings, in which: Figure 1 shows a refrigerator having a condenser with a regular zigzag profile according to the present invention. Figure 2 shows a perspective view of a flat condenser built in the first step of the method according to the invention. Figure 3 shows a perspective view of a condenser bent in such a way to show a zigzag profile in the second step of the method according to the invention. Figure -4 shows a refrigerator having a condenser with saw tooth profile. Figure 5 shows a refrigerator having a condenser with a irregular broken-line profile. With reference to figure 1, a refrigerator 1 is positioned with its rear against a wall 2 of a room. The serpentine condenser of the refrigerating circuit is fitted externally to the rear face of the same refrigerator 1. Between the rear face of the same refrigerator 1 and the wall 2 of the room, a space may be left with a specified minimum distance, for the purpose of forming a kind of vertical conduit, in which will be generated a spontaneous rising flow of air which sweeps past and cools the condenser. The condenser 3 which is a serpentine heat exchanger shows a zigzag profile when seen in the lateral elevation, i.e. from the side. The profile is a serrated one with triangular teeth which are isosceles and all the same, but which may also be irregular and differing between themselves. Figures 2 and 3 illustrates the two steps of the method for building such am exchanger. In the first step (fig. 2) , the condenser or exchanger is built as a usual flat one. So it is possible to use the same lines of production of usual exchanger or condenser. The second step concerns the bending, moulding, or deforming the flat exchanger 3 in the definitive zigzag profiled one. In order to bend, mould, or deform the flat exchanger to the bent, in the case of figures 1 to 3, zigzag configuration ; it is possible to use any kind of means, like bending devices, moulds, or other kinds of deforming devices. As figures 2 and 3 clearly show. preferably the serpentine 103 of the exchanger 3 is oriented in such a way that the parallel sections 203 of the pipe are oriented transversally to the direction of the air flow passing through the exchanger, particularly substantially parallel to the lines of bending. Preferably, the lines of bending are chosen in the vicinity of the parallel sections 203 of the serpentine pipe. Particularly, the bending lines can be chosen also perfectly coaxial with the corresponding sections 203 of the serpentine pipe 103. In this case the serpentine pipe is not submitted to a bending which is transversal to its axis and which can lead to a weakening of the serpentine and to the throttling of the pipe in the zone of bending. The serpentine pipe is submitted to a torsion substantially around its axis, and this kind of deformation eliminates the danger of any throttling. As it results also from figure 2, the wires 303 which are fitted on both of the opposite sides of the serpentine are positioned staggered the ones of one side with respect to the other on the opposite side This feature avoids any interference of the wires 303 with one another during bending of the βxcshanger 3 from its flat configuration to the bent one. The angle of bending the inclined sections depends on the different materials and on the kind of structure of the exchanger and may be calculated. According to figures 4 and 5, the configuration of the exchanger which may be obtained with the method according to the present invention is not limited to a regular zigzag profile. Depending on the distances between the sections 203 of the serpentine pipe 103 which are parallel to the bending lines, it is also possible to construct exchangers having a saw tooth profile or a profile according to an irregular shaped broken line. In the last case it is also possible to construct a serpentine having different distances between two adjacent serpentine pipe sections 203. This allows to obtain a very large number of different irregular or combined configurations. In the examples shown in the figures, the lines of bending and the coinciding sections 203 of the serpentine pipe 103 are oriented transversally to the direction of the flow of air passing through the exchanger 3

Claims: CLAIMS 1. A method for building a serpentine heat exchanger, particularly a condenser for refrigerating circuits being profiled in such a way to present from a lateral side view and relative to at least oπ.ι part of its length an inclination the direction of which is suddenly or progressively inverted at least once relative to a plane which is substantially parallel to one of the directions defined by the extension of the exchanger (3) , in particular relative to a plane substantially parallel to the principal direction of a flow of air in which the exchanger (3) is located, and in special manner relative to a substantially vertical or substantially horizontal plane, characterised by the following steps: a) the construction at least of the serpentine or of the complete exchanger in a flat configuration; b) the bending and/or moulding, or deforming of the flat serpentine or of the flat complete exchanger in a way to assume the desired inclinations. 2. A method according to claim 1 comprising the step of fixing strengthening wires (303) to each side of a flat serpentine (103) being the wires (303) on the opposite sides of the serpentine (103) placed staggered one with respect to the other. 3. A Method according to claim 1 or 2, characterised in that the bending lines of the flat exchanger (3') i.e. the lines at which the direction of the inclined parts suddenly or progressively changes in order to ensure the at least two different inclinations in opposite direction one to the other takes place at least along lines in the vicinity of and parallel to pipe sections (203) of the serpentine, preferably along and more specifically coaxial to the said pipe sections. . A method according to one or more of the preceding claims, characterised in that the bending lines are provided at the same regular distances one from the other. 5. A method according to one or more of the preceding claims 1 to 3, characterised in that the bending lines are provided at different distances one from the other which are equivalent to an integer factor of the distances between the parallel sections (203) of the serpentine pipe (103) . 6. A method according to one or more of the preceding claims 1 to 3, characterised in that the serpentine (103) may show pipe sections (203) parallel or coinciding with the bending lines which are located at different distances one from the other. 7. Serpentine heat exchanger, particularly a condenser for refrigerating circuits being profiled in such a way to present from a lateral side view and relative to at least one part of its length an inclination the direction of which is suddenly or progressively inverted at least once relative to a plane which is substantially parallel to one of the directions defined by the extension of the exchanger (3) , in particular relative to a plane substantially parallel to the principal direction of a flow of air in which the exchanger (3) is located, and in special manner relative to a substantially vertical or substantially horizontal plane, characterised in that the inclined sections are obtained by bending, moulding or otherwise deforming a flat exchanger (3' ) . 8. Serpentine heat exchanger according to claim 7 , characterised in that the serpentine (103) has pipe sections (203) which are at least parallel to the bending lines, i.e. to the lines at which the direction of the inclined parts suddenly or progressively changes in order to ensure the at least two different inclinations in opposite direction one to the other and which are provided at the vicinity, or along, in particular coaxial to the said bending lines. 9. Serpentine heat exchanger according to claim 7 or 8, characterised in that strengthening wires (303) are fitted to each side of the serpentine (103) being the wires (303) on the opposite sides of the serpentine (103) placed staggered one with respect to the other. Serpentine heat exchanger according to one or more of the preceding claims to , characterised in that the bending lines are provided at the same regular distances one from the other the exchanger showing section (203) of the serpentine (103) parallel to the said bending lines which are spaced apart at the same regular distance. 10. Serpentine heat exchanger according to one or more of the preceding claims 7 to 9, characterised in that the bending lines are provided at different distances one from the other which are equivalent to an integer factor of the distances between the parallel sections (203) of the serpentine pipe (103) . Serpentine heat exchanger according to one or more of the preceding claims to , characterised in that the serpentine (103) may show pipe sections (203) parallel or coinciding with the bending lines which are located at different distances one from the other. 11. Serpentine heat exchanger according to one or more of the preceding claims characterised in that it may assume regular zigzag profile, a saw tooth profile or a profile according to an irregular broken line. AMENDED CLAIMS [received by the International Bureau on 23 April 1997 (23.04.97); original claims 1 and 2 amended; remaining claims unchanged (1 page) 1. A method for building a serpentine heat exchanger, particularly a condenser for refrigerating circuits being profiled in such a way to present from a 5 lateral side view and relative to at least one part of its length an inclination the direction of which is suddenly or ■ progressively inverted at least once relative to a plane which is substantially parallel to one of the directions defined by the extension of the 10 exchanger (3) , in particular relative to a plane substantially parallel to the principal direction of a flow of air in which the exchanger (3) is located, and in special manner relative to a substantially vertical or substantially horizontal plane, characterised by the 15 following steps: a) bending a pipe into a flat serpentine configuration (103); b) attaching wires (303) to each side of the flat, serpentine (103); and c) bending and/or moulding, or deforming the flat serpentine 0 (103) and the wires attached thereto to afford a heat exchanger (3) having the desired inclinations. 2. A method according to claim 1, in which the wires (303) attached to opposite sides of the flat serpentine (103) are staggered one with respect to the other. 3. A Method according to claim 1 or 2, characterised in that the bending lines of the flat exchanger (3') i.e. the lines at which the direction of the inclined parts suddenly or progressively changes in order to ensure the at least two different inclinations 0 in opposite direction one to the other takes place at least along lines in the vicinity of and parallel to STATEMENT UNDER ARTICLE 19 Claim 1 has been amended by inserting a limitation which clearly differentiates the claim from the cited prior art, and a consequent amendment of claim 2 has been made. Corresponding amendments are required to pages 2 and 3 of the specification at present on file.

Inventors: DALL ORO ROBERTO, PICCO PIER LUIGI, PRATO REMO, DALL'ORO, ROBERTO, PICCO, PIER, LUIGI, PRATO, REMO
Applicants: BUNDY INT LTD, DALL ORO ROBERTO, PICCO PIER LUIGI, PRATO REMO, BUNDY INTERNATIONAL LIMITED, DALL'ORO, ROBERTO, PICCO, PIER, LUIGI, PRATO, REMO
Application year: 1996
Main classification: F28D1
IPC codes: B21D53, B23P15, F25B39, F28D1