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(11) | EP 0 421 955 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Water-tube heat exchanger for a motor vehicle air-conditioning system, having a header with a baffle for dividing the flow |
| (57) A water-tube radiator for a motor-vehicle air-conditioning system includes a header
with a cover (16) of polymeric material welded ultrasonically to a flow-dividing baffle
(20) with a flat base portion (20a) which faces the tube plate (is) with the interposition
of a flat gasket (22) of elastomeric material. The base portion (20a) of the baffle
(20) has a plurality of U-shaped connectors (27) arranged to cause the liquid to pass
tube-side more than twice without the need for more than one flow-dividing baffle.
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[0001] The present invention relates to a liquid-gas heat exchanger with water tubes, particularly for a motor-vehicle air-conditioning system, of the type including a header with a tube plate, a cover and a baffle for dividing the flow.
[0002] In current solutions, one side of the flow-dividing baffle is connected to the convex cover of the header and the other side is connected to the tube plate with the interposition of a gasket. It is thus possible to form a water-tube heat exchanger in which the water passes tube-side twice. If one wishes to increase the number of times the liquid passes tube-side, and hence the efficiency of the exchanger, it is necessary to use several flow-dividing baffles which complicate the manufacture of the exchanger and can create sealing problems between the baffles and the tube plate.
[0003] The object of the present invention is to provide an exchanger of the type specified at the beginning of the description, which allows the liquid to pass tube-side several times without complications in the structure of the exchanger.
[0004] According to the invention, this object is achieved by virtue of the fact that the flow-dividing baffle is interposed sealingly between the cover and the tube plate and has liquid-channelling means for causing the liquid to pass tube-side several times.
[0005] Preferably, the baffle has a flat base portion facing the tube plate and a flow-dividing portion substantially perpendicular to the base portion and having a free edge connectible to the cover of the header by pressure or by ultrasonic welding.
[0006] By virtue of these characteristics, an exchanger with water tubes can be formed with three or more "rows" (that is, with sets of finned tubes arranged substantially in three different parallel planes) and a flow-divider, without complications in the assembly of the exchanger, in the arrangement of the baffles or in the positioning of the liquid-inlet and -outlet connectors.
[0007] Further advantages and characteristics of the exchanger according to the invention will become clear from the detailed description which follows, purely by way of non-limiting example, with reference to the appended drawings, in which:
Figure 1 is a perspective view of an exchanger according to the invention,
Figure 2 is an exploded perspective view of the exchanger of Figure 1,
Figure 3 is a view of a detail of Figure 2 on an enlarged scale,
Figure 4 is a section taken on the line IV-IV of Figure 1,
Figure 5 is a section taken on the line V-V of Figure 1,
Figure 6 is a section taken on the line VI-VI of Figure 1,
Figure 7 is a section taken on the line VII-VII of Figure 1,
Figure 8 is a section taken on the line VIII-VIII of Figure 1, and
Figure 9 is a section taken on the line IX-IX of Figure 1.
[0008] With reference to the drawings (Figure 1), a liquid-gas heat exchanger with three rows of water tubes suitable for installation in a motor-vehicle air-conditioning system is generally indicated 10. The exchanger 10 has a finned matrix 10a composed of finned U-shaped tubes arranged between a header 12 and a tube-support frame 14.
[0009] The header 12 includes a convex cover 16 of polymeric material which has a recessed portion 17 formed with two lateral connectors 16a and 16b for respective connection to inlet and outlet tubes for the liquid, a metal tube plate 18 with a plurality of holes 18a for the passage of the tubes T, and a baffle 20 of polymeric material whose characteristics will become clear from the following description (Figure 2).
[0010] The baffle 20 has a flat base portion 20a which faces the tube plate 18 with the interposition of a flat gasket 22 of elastomeric material having a plurality of holes 22a for the passage of the ends of the tubes T, and a substantially L-shaped, flow-dividing portion 20b perpendicular to the base portion 20a. The latter has two series of through-holes 23 and 25 respectively, arranged on opposite sides of the portion 20b of the baffle 20, as well as a plurality of elongate recessed portions 27 with substantially channel-shaped cross-sections arranged in correspondence with adjacent pairs of tubes T in an arrangement which, as shown clearly in Figures 2 and 3, forces the liquid circulating in the tubes in the central plane of the matrix 10a to be conveyed either into other tubes in the central plane (the recesses indicated A in Figures 3 and 5) or into tubes in planes parallel to the central plane of the matrix (the recesses indicated B in Figures 3 and 5).
[0011] The portion 20b of the ale 20 has a free edge E which is connected (by pressure or by ultrasonic welding), during the assembly of the exchanger, to the corresponding edge E′ of a central baffle plate 30 formed on the base wall 32 of the cover 16 of the header 12 (Figure 8).
[0012] As can clearly be seen in Figures 8 and 9, the edge E of the portion 20b of the baffle 20 is V-shaped and corresponds in shape to a V-shaped recess formed in the edge E′ of the baffle plate 30.
[0013] During the assembly of the exchanger, the edge of the metal tube plate 18, indicated 18b, is folded over a shaped edge 16c of the cover 16 with the interpositon of the edge 22b of the flat gasket 22. The latter is therefore used both to effect a seal between the cover 16 and the tube plate 18 and to effect a seal between the baffle 20 and the tube plate 18 in order to prevent the leakage of liquid between its various passages tube-side (Figures 2 and 8).
[0014] When the exchanger 10 is in use, the fluid admitted by the connector 16a is forced by the portion 20b of the baffle 20 to pass through the first series of holes 23 and to flow along a first set of U-shaped tubes of the matrix 10a and back again. After its first two passages through the matrix 10a, the liquid is returned thereto by the U-shaped recesses 27 and thus passes twice more through the matrix of finned tubes 10a. The liquid returning from its fourth and last passage through the matrix of tubes flows through the second series of holes 25 and is conveyed to the outlet connector 16b of the exchanger 10 (Figure 2).
1. A heat exchanger, particularly a liquid-gas or a liquid-liquid heat exchanger with
tubes for a motor-vehicle air-conditioning or cooling system, of the type including
at least one header (12) with a tube plate (18), a cover (16) and a baffle (20) for
dividing the flow, characterized in that the baffle (20) is interposed sealingly between
the cover (16) and the tube plate (18) and has liquid-channelling means (27, A, B)
for causing the liquid to pass tube-side several times.
2. An exchanger according to Claim 1, characterized in that the baffle (20) has a
flat base portion (20a) which faces the tube plate (18) and a flow-dividing portion
(20b) substantially perpendicular to the base portion (20a) and having a free edge
(E) for connection to the cover (E′, 30, 32, 16) of the header (12).
3. An exchanger according to Claim 2, of the type in which the liquid passes through
the tube side four or more times, characterized in that the flat base portion (20a)
of the baffle (20) has a first series of holes (23) coaxial with the tubes (T) which
admit the liquid to the tube matrix (10a) and a second series of holes (25) coaxial
with the tubes (T) which discharge the liquid from the tube matrix (20a), and a plurality
of U-shaped connectors (27) integral with the baffle (20).
4. An exchanger according to Claim 3, characterized in that a flat sealing gasket
(22) of elastomeric material is interposed between the flat base portion (20a) and
the tube plate (18) and has a plurality of holes (22a) for the passage of the tubes
(T) of the tube matrix (10a).
5. An exchanger according to any one of Claims 2-4, characterized in that the cover
(16) of the header (12) has a flat base portion (32) with an integral baffle plate
(30) substantially perpendicular to the base portion (32) and having a free edge (E′)
which is adapted to be connected end-to-end to the free edge (E) of the flow-dividing
portion (20b) of the baffle (20).
6. An exchanger according to any one of the preceding claims, characterized in that
it has only one header (12) and one matrix of U-shaped tubes (T).