WO2008087526A2

WO2008087526A2 - Modular exchanger for automotive refrigeration system

Info

Publication number: WO2008087526A2
Application number: PCT/IB2008/000084
Authority: WO
Inventors: Carlo Tossi; Paolo Mussi
Original assignee: Ti Automotive Cisliano S.R.L.
Priority date: 2007-01-15
Filing date: 2008-01-09
Publication date: 2008-07-24
Also published as: EP2102576A2; EP2102576B1; WO2008087526A3; ITMI20070048A1

Abstract

A modular exchanger (10) for an automotive refrigeration system (1), comprises at least one exchanger pack (11) in turn comprising a battery of stacked exchange plates (20), each exchange plate has a first surface (21) furrowed by a plurality of parallel grooves (22), and a second flat continuous surface (23) opposite to the first, the exchange plates (20), are juxtaposed in such a manner that the grooves (22) of an exchange plate define with the continuous flat surface (23) of a plate laid over the first, a series of parallel pipes (24) for the circulation of the pressurised (Fa) or low pressure (Fb) operating fluid, provided in each of such exchange plates (20) are a plurality of first and second openings (51,52) respectively having the function of inlet/outlet or passing through of the fluid (Fa, Fb), the parallel grooves of each exchange plate (20) are arranged perpendicularly to the ones of the exchange plate arranged above and/or below.

Description

MODULAR EXCHANGER FOR AUTOMOTIVE REFRIGERATION SYSTEM

The present invention regards a modular exchanger for an automotive refrigeration system.

According to the known art, the automotive industry refrigeration systems, comprise a circuit within which the refrigerant flows.

Such circuit which in turn comprises a refrigerating exchanger which uses the external air, an expansion valve (lamination) , an evaporator and a compressor.

In addition, recent systems are provided with an exchanger capable of recovering the enthalpy of the pressurised fluid in favour fluid the low pressure fluid. An example of a conditioning unit provided with an additional exchanger is indicated in the United States patent application US2004/0055320 on behalf of Horstmann et al .

Generally, the use of the additional exchanger entails greater space requirements of the system and further piping of the refrigerant.

In addition, the exchange efficiency is a very important parameter as far as the efficacy of the entire refrigeration system is concerned. Thus, currently there is need to manufacture an exchanger for an automotive refrigeration system occupying least space and capable of high exchange efficiency.

The applicant observed that it was possible to meet said needs by providing a modular exchanger for an automotive refrigeration system which can be manufactured in one or more configured modules compatible with an accumulator of the refrigeration system.

Therefore, according to a first aspect of the invention, a modular exchanger for an automotive refrigeration system is provided, intended for recovering the enthalpy of the operating fluid of the system, which comprises at least an exchanger pack in turn comprising a battery of stacked exchange plates. Each exchange plate has a first surface furrowed by a plurality of parallel grooves, and a second continuous flat surface, opposite to the first, the exchange plates being juxtaposed in a such manner that the grooves of an exchanger plate define with the continuous flat surface of a plate laid over the first, a series of parallel pipes for the circulation of the pressurised operating fluid or low pressure operating fluid. Provided in each of such exchanger plates there are a plurality of first and second openings respectively having the inlet/outlet or fluid passage function. The pipes of each exchange plate are arranged perpendicularly to those of the heat exchanger arranged above or below.

First said aspect of the invention is the subject of claim 1. Further aspects of the invention are the subject of the dependent claims.

Characteristics and advantages of the modular exchanger for an automotive refrigeration system according to the present invention shall be clearer from the following exemplifying and non- limiting description with reference to the schematic drawings attached wherein:

Figure 1 is a schematic view of an automotive refrigeration system; Figures 2 and 3 are exploded perspective views of a modular exchanger according to the invention;

Figure 4 is an exploded perspective view of a pack of exchange plates of the modular exchanger according to the invention; Figure 5 is a cross-sectional schematic view of an exchanger according to the invention;

Figure 6 is an exploded perspective view of an exchanger according to invention integrated to an accumulator; Figure 7 is a perspective view of an exchanger according to the invention provided with connections - A -

for installation;

Figures 8a and 8b illustrate, in exploded perspective view, a pack of exchange plates of the modular exchanger respectively according to the initial embodiment and according to a further developed embodiment of the invention.

With reference to the figures, an automotive refrigeration system 1 comprises a circuit 2 within which the refrigerant flows. In the system 1 which is substantially a compression refrigeration system, a low pressure operating fluid Fb, carbon dioxide, CO₂, is subjected to compression which raises its pressure turning it into pressurised fluid Fa. After transferring part of its enthalpy, according to the exchange indicated by the arrow Cl , the pressurised fluid Fa is expanded and converted into low pressure fluid Fb which removes the enthalpy from the environment to be refrigerated. Thus the circuit 2 comprises a refrigerating exchanger 3 which uses external air to cool the pressurised fluid Fa, downstream of the exchanger 3 the circuit is provided with an expansion valve 4 which provides for the lamination of the pressurised fluid Fa converting it into low pressure fluid Fb.

Provided downstream of such valve is an evaporator 5 which implements the useful effect of the system removing heat from the environment to be refrigerated according to the exchange indicated by arrow C2.

The fluid Fb flowing out of the evaporator has two phases in that the evaporation is not complete and some drops of liquid L present are drawn by the vapour V.

In addition, the fluid might also draw very small amounts of lubricating oil in form of drops.

The system comprises an accumulator 6 arranged downstream of the evaporator and upstream of a compressor 7 and having the function of guaranteeing continuous flow of the fluid into the compressor 7.

Between the accumulator and the compressor, in the low pressure circuit portion, and correspondingly between the refrigerator and the expansion valve, in the pressurised pressure circuit, there is a modular exchanger 10.

Such modular exchanger 10 is intended for the recovery of the enthalpy of the pressurised operating fluid Fa subsequently transferring it to the low pressure operating fluid Fb in such a manner to complete the evaporation of the fluid Fb.

Such arrangement of the exchanger is strictly for exemplification purpose given that the exchanger suitably provided with connections can be installed at any position within the system: on the accumulator, on - S -

the external air/CO2 exchanger, on the pipes, suitably according to the geometries of the system and depending on the components provided.

The modular exchanger 10 comprises at least one exchanger pack 11 in turn comprising a battery of stacked exchange plates 20 and it is closed at the ends by a closure plate 12 and a base flange 13 respectively.

Each exchange plate of the exchanger pack has a first surface 21 furrowed by a plurality of parallel grooves 22, and a second flat continuous surface 23, opposite to the first.

The exchange plates 20 are juxtaposed in such a manner that the grooves 22 of an exchange plate define, cooperating with the continuous flat surface 23 of an overlapped plate, a series of parallel pipes 24 for the circulation of the pressurised operating fluid Fa or low pressure operating fluid Fb.

The exchange plates are joined by means of brazing, preferably under vacuum, for air-tight sealing even when subjected to high pressure conditions.

The exchanger pack, or the overlapped exchanger packs, are fastened between the closure plate 12 and the base flange 13 which are provided with through holes 53, provided correspondingly also on the exchange plates 20, in order to allow fastening by means of bolts or by means of screws inter-engaged in corresponding holes 73 made on the upper portion of the accumulator 6 when the exchanger 10 is made in a manner such to be integrated with the latter. Such through holes 53 have the end 54, opening in the closure plate, widened to accommodate the head of the fastening screw.

Provided for in each of such exchange plates 20 is a plurality of first and second openings 51, 52 respectively having the inlet/outlet function or the function of passing the fluid Fa, Fb.

Should the exchanger be made up of several overlapped exchanger packs 11, a separation plate 15 provided with openings 51 and 52 and through holes 53 is interposed between the exchanger packs.

The first exchange plate 20 of the first pack 11 present in the stack, cooperates with the continuous flat surface 23 of the closure plate 12 for the formation of pipes 24 while the first plates of the other exchanger packs arranged below which may be present cooperate with the corresponding continuous flat surfaces 23 of the separation plates.

Thus, the pressurised fluid Fa and the low pressure fluid Fb circulate without mixing, on alternating exchange plates 20.

The pipes 24 of each exchange plate 20 are arranged perpendicularly to the pipes 24 of the exchange plate arranged above and/or below.

In such manner the flow of the pressurised fluid Fa is crossed with respect to the flow of the low pressure fluid Fb.

Each exchange plate thus comprises first openings

51 arranged at the ends of the grooves 22, wherein said grooves 22 converge allowing passage of the fluid between the corresponding exchange plates 20, in other words between alternating exchange plates.

Such first openings 51 intercept two or more grooves and they are made offset along diametrically opposite edge portions of each exchange plate 20.

In the exemplified embodiment, such openings 51 are seven per each end of the series of parallel grooves 22, thus summing up to fourteen per each exchange plate and they are configured shaped in such a manner to optimise the resistance of the exchange plates to high operating pressures to which these are subject. In addition, each exchange plate is correspondingly provided with fourteen second openings 52 intended for the transfer of the fluid between alternating plates.

As a matter of fact, for obvious machining costs reasons the plates are made in a single configuration and then they are mounted rotated by 90°.

The grooves 22 are made of different lengths in such a manner to keep their ends far apart and thus position the openings 51 or 53 offset distancing them from each other to obtain a greater structural resistance of the plate. Alongside the holes 53 and the their widened ends 54, the closure plate of the exchanger is also passed through by seats for the refrigerant transfer blocks, respectively a first seat 60 for the inlet of the pressurised refrigerant Fa and a second seat 61 for the outlet of the low pressure refrigerant Fb.

Provided in proximity to such outlet seats are threaded holes 62 for fastening the blocks (not illustrated) .

Correspondingly, the base flange 13 is provided with seats 80 and 83 in which the transfer nozzles are brazed, respectively an Fa fluid outlet nozzle 81 and an Fb fluid inlet nozzle 82, into the exchanger.

Such seats 80, 83 open internally in two separated chambers 55 obtained on the surface of the flange 13 and which connect openings 51 52 respectively.

Such nozzles 81, 82 can be directly inserted into corresponding holes made in the upper portion of the accumulator which, as required, is provided with seats 70 and 71. In particular, a pair of seats 70, 72 for the passage of the pressurised fluid Fa which does not pass thorough the accumulator and a pair of seats 74, 71 respectively for inlet and outlet of the low pressure fluid Fb which passes through the accumulator.

In addition, provided in proximity to each seat is a threaded fastening hole 73 of the blocks to be inserted into the seat or of the end portion of the screws which secure the exchanger against the accumulator.

For a dimensional and performance optimisation of the exchanger, the latter is shaped cylindrically and preferably it has a diameter substantially equivalent to the diameter of the accumulator in such a manner to be integrated with the latter into a single body, when assembled on the accumulator as shown in figure 6. According to the exemplified embodiment of the invention, each exchanger pack includes sixteen alternating plates and the modular exchanger 10 has two exchanger packs. However, both such numbers may vary depending on the preset exchange parameters and the overall dimensions of the system.

A further developed and alternative embodiment of the exchanger is illustrated in figure 8b and provides for a different sequence of the plates inside the exchanger packs . While in the embodiment described up to now and also illustrated in figure 8a there is an alternation between a first plate 20' within which the high pressure fluid Fa passes and a second plate 20'' within which a low pressure fluid Fb passes, in the further developed and alternative embodiment, the sequence of the plates is as follows: the second plate 20'' within which the low pressure fluid Fb passes - the first plate 20' - within which the high pressure fluid Fa passes and once again the second plate 20'' within which the low pressure fluid Fb passes; this sequence is repeated until the desired number of plates of the exchanger pack is obtained.

According to this further developed and alternative embodiment of the invention, each exchanger pack includes fifteen plates arranged following the sequence described beforehand, and in the modular exchanger 10 there are two exchanger packs; both such numbers may vary depending on the preset exchange parameters and the overall dimensions of the system.

Illustrated in figure 7 is a different embodiment of the modular exchanger 10 provided for allowing assembly of the modular exchanger and other devices present in the system, at any position in the system, such as for example on the external air/C02 exchanger, on the pipes, in such a manner to be able to position the modular exchanger appropriately suiting its arrangement to the geometries of the system and depending on the components provided.

For such purpose, assembled on the closure plate 12, the modular exchanger 10 bears two first blocks 33 respectively bearing an inlet pipe 30 for the pressurised Fa fluid and an outlet pipe 31 for the low pressure Fb fluid, and in the base flange 13 two second blocks respectively bearing an inlet pipe 90 for the low pressure Fb fluid and an outlet pipe 91 for the pressurised Fa fluid. Such blocks are provided with through holes 62' for fastening, by means of screws, the same against the holes 62 provided on the closure plate 12 and in the base flange 13.

In such manner, the exchanger can effectively be deemed to be a modular component suitably assemblable according to the manner, at the position and on the most convenient component in the referigeration system.

Claims

1. Modular exchanger (10) for an automotive refrigeration system intended for recovering the enthalpy of the operating fluid (Fa, Fb) of the system, comprises at least an exchanger pack (11) in turn comprising a battery of stacked exchange plates (20) , each exchange plate has a first surface (21) furrowed by a plurality of parallel grooves (22), and a second flat continuous surface (23) opposite to the first, the exchange plates (20) , being juxtaposed in such a manner that the grooves (22) of an exchange plate define with the continuous flat surface (23) of a plate laid over the first, a series of parallel pipes (24) for the circulation of the pressurised (Fa) or low pressure (Fb) operating fluid, provided in each of such exchange plates (20) are a plurality of first and second openings (51, 52) respectively having the function of inlet/outlet or passing through of the fluid (Fa, Fb) , the pipes (24) of each exchange plate (20) are arranged perpendicularly to the ones of the exchange plate arranged above and/or below.

2. Modular exchanger (10) according to claim 1, wherein said at least one exchanger pack (11) is closed at the ends respectively by a closure plate (12) and by a base flange (13) .

3. Modular exchanger (10) according to claim 2, wherein the air-tight sealing joining of said exchange plates (20) can be performed by means of vacuum brazing.

4. Modular exchanger (10) according to claim 1, wherein said exchanger pack (11) , or overlapped exchanger packs

(11), are fastened between the closure plate (12) and the base flange (13) which are provided with through holes (53) , provided correspondingly also on the exchange plates (20) , to allow fastening by means of bolts or by means of screws inter-engaging in corresponding holes (73) made on the upper portion of the accumulator (6) when the exchanger (10) is made in such a manner to be integrated with the latter.

5. Modular exchanger (10) according to claim 1, wherein each of said exchange plates (20) comprise first openings (51) arranged at the ends of the grooves (22) , in which said grooves (22) converge to allow the passage of the fluid between corresponding exchange plates (20) , in other words between alternating exchange plates, such first openings (51) intercept two or more grooves and are made offset along diametrically opposite edge portions of each exchange plate (20) .

6. Modular exchanger (10) according to claim 5, wherein said openings (51) are seven per each end of the series of parallel grooves (22) , thus summing up to fourteen per each exchange plate (20) and they are configured in a shaped manner.

7. Modular exchanger (10) according to claim 6, wherein each exchange plate is additionally provided with fourteen second openings (52) intended for the transfer of the fluid between alternating plates.

8. Modular exchanger (10) according to claim 1, wherein the grooves (22) are made with different lengths in such a manner to keep their ends apart and thus position the openings (51, 52) offset distancing them from each other to obtain a greater structural resistance of the plate.

9. Modular exchanger (10) according to claim 8, wherein said closure plates (12) of the exchanger is not only passed through by the holes (52) and provided with widened ends (54) but are also passed through by seats for refrigerant transfer blocks, respectively a first seat (60) , for the inlet of the pressurised fluid (Fa) and a second seat (61) for the outlet of the low pressure fluid (Fb) , in proximity to such seats being provided threaded holes (62) for the fastening of the blocks .

10. Modular exchanger (10) according to claim 9, wherein said base flange (13) is provided with inlet seats (80, 83) in which corresponding transfer nozzles are brazed, respectively nozzle (81) for the outlet of the fluid (Fa) and a nozzle (82) for the inlet of the fluid (Fb) into the exchanger.

11. Modular exchanger (10) according to claim 10, wherein said nozzles (81, 82) are arranged to be inserted directly into the corresponding holes made on the upper portion of the accumulator which, as required, is provided with seats (70, 71, 72, 74), respectively, a pair of seats (70,72) for the passage of the pressurised fluid (Fa) which does not pass through the accumulator and a pair of seats (74, 71) respectively for inlet and outlet of the low pressure fluid (Fb) which passes through the accumulator, in proximity of each seat there is additionally a fastening threaded hole (73) for blocks to be inserted in the seat or of the end portion of the screws securing the exchanger against the accumulator.

12. Modular exchanger (10) according to claim 11, wherein said exchanger (10) is made in a cylindrical shape and has a diameter substantially equivalent to the accumulator (6) in such a manner to integrate with the latter into a single body.

13. Modular exchanger (10) according to claim 1, wherein each exchanger pack (11) includes sixteen plates (20) alternating according to the following sequence of two plates: a first plate (20') wherein the high pressure fluid (Fa) passes, a second plate (20'') wherein the low pressure fluid (Fb) passes, the modular exchanger (10) being provided with two exchanger packs (11) •

14. Modular exchanger (10) according to claim 1 , wherein each exchanger pack (11) is made up of fifteen plates (20) arranged repeating the following sequence of three plates: a second plate (20'') wherein the low pressure fluid (Fb) passes, a first plate (20') wherein the high pressure fluid (Fa) passes and once again a second plate (20'') wherein the low pressure fluid (Fb) passes, the modular exchanger (10) being provided with two exchanger packs (11) .

15. Modular exchanger (10) according to claims 13 and 14, wherein there is a separation plate (15) provided with openings (51, 52) and through holes (53) interposed between the exchanger packs.

16. Modular exchanger (10) according to claim 1, wherein said modular exchanger (10) bears assembled in the closure plate (12) two first blocks (33) respectively bearing an inlet pipe (30) for the pressurised fluid (Fa) and an outlet pipe (31) for the low pressure fluid (Fb), and in the base flange (13) two second blocks respectively bearing an inlet pipe

(90) for the low pressure fluid (Fb) and an outlet pipe

(91) for the pressurised fluid (Fa) .