Patent Application
20240003634
The present invention relates to a heat exchanger, particularly an exchanger of the “plate” type for the conditioning or the refrigeration of fluids.
Generally, the use of heat exchangers allows a heat transfer between a coolant fluid and a fluid to be cooled flowing inside adjacent passage channels and defined in the exchanger between several plates stacked onto each other and contiguous to each other. The channels are alternated with each other to allow heat transfer. The liquid passing through the plates is normally made to flow in cross-flow (counter-current) to increase the generated heat transfer, but parallel conformation (equi-current) is also possible.
Known exchangers, such as those disclosed for example in U.S. Pat. No. 4,815,534, are usually obtained by means of plates made in forming moulds and brazed together in vacuum and/or controlled atmosphere (CAB) furnaces. The moulds are therefore sized depending on the measurements required for the manufacture of the plates, which greatly limits the operational adaptability of the latter. In fact, it follows that plates made for a special exchanger cannot be used for different exchangers with even slightly different dimensions. Every slight variation in size and/or characteristics makes it necessary to invest heavily in new moulds, which limits the flexibility and production output of heat exchanger manufacturers.
The Applicant realized the need to develop a solution that would allow the production of extremely versatile plates for heat exchangers, adaptable to variable dimensions and therefore operable in any model of heat exchanger. In this way, the classic process of manufacturing plates has been completely modified, avoiding the need to make expensive and complex moulds.
The Applicant has thus designed a plate consisting of several parts which can be joined together and made by means of diversified processes that are on the whole cheaper than known construction processes, in order to free oneself from the constructional manufacturing dimensions, thus ensuring dimensional changes even of a few millimeters.
Therefore, the present invention relates to a heat exchanger according to claim 1 which enables to overcome the aforementioned drawbacks of the prior art in the context of a simple, rational, easy and effective to use as well as affordable solution.
Other characteristics and advantages of the present invention will become more apparent from the description of a preferred, but not exclusive, embodiment of a heat exchanger, illustrated by way of an indicative, yet non-limiting example, in the accompanying tables of drawings wherein:
With particular reference to these figures, reference numeral 1 globally indicates a heat exchanger according to the present invention.
The exchanger 1 is provided with a plurality of heat exchange plates 2 and plaques 3 stacked one by one on each other along a stacking direction Y-Y. Conveniently, as shown in
In the volume space comprised between two adjacent plaques 3, respective coolant passage channels 4 and passage channels to be cooled 5 are defined which are crossed, respectively, by the coolant fluid C and the fluid to be cooled H.
Preferably, the fluid passing in the channel to be cooled 5 is oil while the fluid passing in the coolant channel 4 is water. The channels 4, 5 are arranged perpendicularly with respect to the stacking direction Y-Y while they result alternating with each other along said direction Y-Y.
With reference to the example illustrated in
Preferably, each lateral plate 8, 9 is made from an aluminum strip plated with low melting material and subsequently shaped, e.g. by laser cutting, to obtain a particular shape similar to a spectacle frame, as illustrated in the various examples attached in the figures.
In particular, each lateral plate 8, 9 has a closed contour ring portion 12 and an open contour curvilinear portion 13 joined together by a central connecting portion 14. The ring portion 12 has a through opening 15 while the curvilinear portion 13 is defined by a curvilinear extension 16.
Around the through opening 15 of the ring portion 12, there are a pointed upper portion 17, a curved lateral portion 18 and an enlarged lower portion 19 which serves as a base for the ring portion 12. At the connection area between the pointed upper portion 17 and the curved lateral portion 18 there is a housing 20 to receive, by shape coupling, one of the ends 11a, 11b of the second connecting bar 11.
With reference to the open contour curvilinear portion 13, the latter is also characterized by the presence of a pointed upper portion 21, substantially identical to the pointed upper portion 17 of the ring portion 12, and connected to the curvilinear extension 16. Conveniently, the curvilinear extension 16 ends up with a further housing 20 to receive, by shape coupling, one of the ends 10a of the first connecting bar 10. In substance, the closed contour ring portion 12 differs from the open contour curvilinear portion 13 in the presence of the enlarged lower portion 19. In the examples of
According to a further embodiment shown in the example of
Further non-illustrated embodiments cannot however be ruled out wherein the housings 20 have different shapes always in order to achieve a stable coupling by shape with the respective ends of the bars 10, 11.
As shown in the example of
Preferably, the first lateral plate 8 is substantially identical to the second lateral plate 9. This makes the construction of the exchanger extremely simplified since it requires a single size of the lateral plates 8, 9. As can be seen, in fact, a same lateral plate 8, 9 may be rotated around the central connecting portion 14 and used so that its through opening 15 receives, depending on its positioning, the coolant fluid C and/or the fluid to be cooled H.
With reference to the embodiment of
According to an embodiment of the invention, each plate 2 may comprise a wire mesh 23 housed inside the volume comprised between two plaques 3 internally to the modular frame made by the inner sides of the bars 10, 11 and the inner sides of the extensions 16 of each lateral plate 8, 9. Advantageously, the wire mesh 23 is made from a press-formed strip and located inside the modular frame with the purpose of creating turbulence and facilitating heat exchange in the channels. Conveniently, the wire mesh 23 may be suitably shaped to follow the profile of the modular frame.
The Applicant has carried out several tests to verify the performance of the new exchanger according to the present invention.
An initial static pressure resistance test proved the complete sealing of the elements making up the exchanger. In particular, after brazing and before welding the connection sleeves, a test rig with a gasket system was used to ensure complete sealing and the exchanger was placed in a tank full of water. By applying pressurized air inside the exchanger, the absence of porosity and/or brazing failures was verified. For the test, the oil pressure in the channel to be cooled was brought up to 30 bar (required value 24 bar), while in the coolant channel the water pressure value was brought up to 6 bar (required value 3 bar). The same test was also repeated after welding the connection sleeves to ensure that the welding phase had not induced any damage to the brazing joints.
A second anti-mix test also showed that there were no leaks between the channels. In particular, the coolant channels were filled with water and the channels to be cooled with compressed air at a static pressure of about 5 bar. It has been verified that no bubbles escaped from the channels due to the passage of air. The test showed that even after previous tests there were no damage effects between the channels.
A further fatigue test at cyclic pressure according to the ISO 10771-1 specification allowed verifying the absence of leakage during predetermined stresses. The exchanger was able to sustain a cyclic operating pressure (between 0 and 16 bar) in the channel to be cooled with oil, with a frequency of about 2 Hz. The oil was brought to a lower temperature of 50° C. Although the standard requires the stress to be maintained for at least 1,000,000 cycles, tests carried out on the exchanger of the invention showed that at the 2,200,000th cycle no rupture was present.
Finally, a test was carried out to verify the heat transfer performance and pressure drop. Two fluids at different inlet temperatures (one at high temperature, the other at low temperature) were made to flow inside the exchanger, thus modifying the flow rates to determine any variations in heat exchange and construct a specific heat exchange power matrix. Also for this test, reduced and negligible pressure drop conditions (both of one fluid and the other) were recorded even with viscosity variations at certain operating flow rates.
It has in practice been ascertained that the described exchanger achieves the intended requirements and, in particular, the fact has been underlined that the manufacture of plates with variable modularity allows the adaptability to any model of exchanger even with dimensions extremely different in length. In addition, the manufacturing process of the lateral plates and of the bars has been greatly simplified, saving money while maintaining the exchanger's optimal performance and reliability.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102020000026251 | Nov 2020 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2021/060159 | 11/3/2021 | WO |
