EP0974804B1 - Heat exchanger, more particularly heat exchanger for exhaust gases - Google Patents

Abstract

The flow channels (2) of the heat exchanger are longer than the flow channels (3) and extend through the collection chamber (4) having inlets and outlets (8, 9). In region (l), in which both flow channels run parallel to each other, the heat exchanger does not have a housing. Heat exchanger , especially waste gas heat exchanger, consists of a stack of heat exchange plates forming divided flow channels running parallel to each other, with collection chambers, and inlet and outlet for the waste gas and for liquid coolant. The flow channels (2) of the heat exchanger are longer than the flow channels (3) and extend through the collection chamber (4) having inlets and outlets (8, 9). In region (l), in which both flow channels run parallel to each other, the heat exchanger does not have a housing.

Description

The invention relates to a heat exchanger, in particular an exhaust gas heat exchanger, consisting of a stack of heat exchanger plates that separate flow form channels that run parallel to each other, with collecting spaces, inlet and outlet for the exhaust gas and for the preferably liquid coolant.

As the German utility model No. 83 19 866 only shows as an example At the beginning of the 80s, exhaust gas heat exchangers were often called so-called Tube bundle heat exchanger designed from a bundle of round tubes exist, which ends at both ends in tube sheets. The inlets and outlets for the Exhaust gases are located at opposite ends. There are also collecting rooms trained, from which the exhaust gas on the individual pipes of the Distributes the bundle and flows through it. The inlets and outlets are in relative Proximity to the other inlets and outlets arranged so that the flow directions cross the two media in this area.

One has become acquainted with such tube heat exchangers, as exhaust gas heat exchangers later removed again because they are unsatisfactory in performance and too large are. The latter mainly because of the required outer housing - mostly in Cylindrical shape - which includes the bundle and the flow channels for that Coolant limited outside. Exhaust gas heat exchangers are required in particular for motor vehicles, that have to be very space-saving with high performance parameters. Round cross-sectional shapes have a lower space utilization.

For this reason and also for reasons of cost, we later switched to to provide so-called houseless plate heat exchangers as exhaust gas heat exchangers, as it e.g. in German Utility Model No. 296 16 354, the from the applicant is shown.

EP 677 715 A1 represents the prior art, of which the preamble has been derived. The exhaust gas heat exchanger there is advantageous because that Exhaust gas without significant deflections that cause pressure losses Can flow through the heat exchanger. However, in the event that the exhaust gas with Water is cooled, the stack of heat exchanger plates by an enclosure enclosed, which leads to the disadvantages already mentioned. Furthermore, the flexibility of the heat exchanger with respect to various connection positions, in particular for the coolant connections, in need of improvement. The plate pack is executed according to the so-called rod-plate construction, which means many individual There are components that need to be assembled. That can be as be viewed elaborately.

The object of the invention is a compact and efficient heat exchanger to propose that is inexpensive to manufacture and a better one Should have flexibility with regard to the installation space and the connection positions. The solution according to the invention results from the patent claims.

The provision of one or two opposite collection rooms for one Medium, preferably for the cooling water, by the flow channels for the other medium, i.e. the exhaust gas, is permeated, leads to very flexible Connection options for the inlet and / or outlet connection, because these can are located anywhere along the entire circumference of the assembly room, without significant effort being required. If a better one Flexibility of the connection position on the exhaust side is desired, of course in the context of the invention, the coolant side with the exhaust side interchange and adjust the flow channels accordingly. Going through the flow channels of one agent through the collecting space of the other By means of the side effect that already exists in the collecting room a heat exchange takes place, which leads to the high efficiency of the total heat exchange contributes.

This could meet the demands of the automotive industry and other users be met in the best possible way.

This also applies to the compact, space-saving design of the heat exchanger, due to the housingless design in the predominant area of the heat exchanger, namely where the flow channels run parallel to each other, has been achieved. The heat exchanger according to the invention has flow channels of different lengths. The range mentioned above corresponds approximately to the length of the shorter flow channels.

Slats are inserted in the flow channels for the exhaust gas, the rectangular slats can be, or have a shape other than rectangular can. Rectangular slats ensure good heat transfer on the one hand, without on the other hand to offer the exhaust gas opportunities to deposit and in the course of Time to close the flow channels.

The heat exchanger plates have knobs on the coolant side. The pimples one heat exchanger plate touch the knobs of the next heat exchanger plate, so that they can be connected to each other and to Compactness of the heat exchanger contribute. However, it is understood that instead of these knobs also fins or other turbulence-generating elements can be provided. Both flow channels are through Merging heat exchanger plates formed, all the same Have shape, which is very advantageous in terms of production technology and to reduce costs contributes. The different length of the flow channels is also through this a kind of heat exchanger plates have been realized. The heat exchanger plates have edges that extend across the entire length of the panels Formed side, for example downwards with respect to the plate level, (Back) and one over the length of the shorter flow channels Have edge characteristics that are opposite to the deformation, i.e. after is formed above the plate level (front). An advantageous embodiment has the ones already mentioned on the same side of the panel (front) Nubs. Two heat exchanger plates each with their over the Total length-reaching edges, so with the back, put together and form the one flow channel between them. The other flow channel is realized in that the next heat exchanger plate on the front Front is placed, which is followed by back to back, etc. The inventive idea with shorter and longer flow channels can of course also - realized differently than described above - thereby be that instead of the edge reshaping and edge stamping rods be inserted, which have the length of the shorter flow channels and the are connected to the plates. In this case the plates are preferably on the opposite longitudinal edges only folded. Two such plates will be then folded together like a box and forming a flow channel within out. The adjacent flow channel is through the mentioned rods formed or limited on the long sides.

Fig. 1 Seitenansicht einer ersten Ausführungsform

Fig. 2 Draufsicht von Fig. 1

Fig. 3 Ansicht aus Richtung des Pfeiles III in Fig. 1

Fig. 4 Ähnlich Fig. 3, aber ohne Abgaseinlaß gezeichnet

Fig. 5 Längsschnitt durch einen Sammelraum

Fig. 6 Schnitt A in Fig. 5, vergrößert

Fig. 7 Ansicht auf einen Rohrboden

Fig. 8 Ähnlich Ansicht A in Fig. 5 - andere Ausführungsform

Fig. 9 Seitenansicht einer weiteren Ausführungsform

Fig. 10 Draufsicht auf eine Wärmetauscherplatte

Fig.11 Ansicht nach Pfeil XI in Fig. 10

Fig.12 Vergrößerter Ausschnitt des Randes der Platte nach Pfeil XII in Fig. 10

According to the proposed inventive principle, the heat exchanger can be used both with opposite collection spaces for the exhaust gas and / or for the coolant and flow in a straight line, as well as with heat exchangers that have a collection space for the exhaust gas and / or for only one side Have coolant and have a deflection space at the opposite end. As is known per se, a separating plate is arranged in the collecting space. The use of these variants improves the flexibility of the connection positions on the exhaust gas side and on the coolant side. The outer flow channels are preferably intended for the coolant because the radiant heat of the heat exchanger can thereby be kept lower. This is not insignificant at exhaust gas temperatures of 700 ° C and more and contributes to the reduction of engine heating, especially for engines in capsule construction. In this variant, there is an end plate on and under the stack of heat exchanger plates, which limit the coolant channel to the outside. This also has the advantage that the connection of the stack of heat exchanger plates with the one tube sheet can be carried out more simply because the opening in the tube sheet is designed as a square. Other possibly important features, which could also prove to be essential to the invention, can be found in the following description of exemplary embodiments. Reference is made to the accompanying drawings, which show the following:

Fig. 1 side view of a first embodiment

2 top view of FIG. 1st

3 view from the direction of arrow III in Fig. 1st

Fig. 4 Similar to Fig. 3, but drawn without an exhaust gas inlet

Fig. 5 longitudinal section through a collecting space

Fig. 6 section A in Fig. 5, enlarged

Fig. 7 view of a tube sheet

Fig. 8 Similar to view A in Fig. 5 - different embodiment

Fig. 9 side view of another embodiment

Fig. 10 plan view of a heat exchanger plate

Fig. 11 View according to arrow XI in Fig. 10

Fig. 12 Enlarged section of the edge of the plate according to arrow XII in Fig. 10

The water-cooled exhaust gas heat exchanger 1 is in a first in FIGS. 1 to 6 Embodiment shown.

The exhaust gas heat exchanger consists entirely of a suitable stainless steel. All connections between the parts are made by soldering. In Fig. 1, the left collecting space 4 for the cooling water and the collecting space 7 drawn for the exhaust gas in section to show details. The exhaust gas flows through the inlet 14 into the collecting space 7 and through the flow channels 2 in a straight path through the heat exchanger 1 to pass this over the Leave outlet 15 again. The inlets and outlets 14, 15 have suitable ones Connections that have been shown here simply as connection flanges. The Cooling water flows at the inlet 8 into the collecting space 4 and is distributed over the Flow channels 3, which run parallel to the flow channels 2 and alternate with these. The collecting rooms 4 are from the tube sheets 5 and 6 been formed, the jacket 5 of the collecting spaces 4 by the erected Edge 12 of the tube sheet 5, the one with the edge of the tube sheet 6 Connection surface 13 forms, has been produced in this embodiment. The stack consisting of identical heat exchanger plates P1 and P2 has shorter flow channels 3 on and longer flow channels 2, what below is explained in more detail. The different lengths L and I of the flow channels 2 and 3 was drawn in Fig. 1. The longer flow channels 2 go through the collecting spaces 4 and are in the openings 17 of the second Pipe base 6 attached sealingly. (see also FIG. 4, in which three openings 17 for which three flow channels 2 are shown)

4 and also FIG. 3 further show that in the flow channels 2 Rectangular fins 25 have been inserted to improve the heat exchange. The fins 25 are with the heat exchanger plates P1 and P2 and with connected to the walls of the flow channels 2.

The tube sheet 5 merely has an opening 16, as shown in FIG. 7. The opening 16 is a rectangle. Fig. 6 shows in an enlarged section the attachment of the Heat exchanger plates P1 and P2 in this opening 16. At the top of the opening 16, an end plate 11 has been drawn. An identical plate 11 is located at the bottom of the opening 16, not shown. The end plates 11 cover the heat exchanger plates P1; P2 completely (Fig. 2) and limit the upper and lower flow channel 3, that for cooling water is provided. In this embodiment, identical heat exchanger plates were used P1 and P2 are used, which have been shown in FIGS. 10 to 12 are. The heat exchanger plates P1; P2 are rectangular here and have consequently two opposite longitudinal edges 21. At these longitudinal edges 21 there is a forming 22 extending over the entire plate length L, which is directed to the rear R of the plate level. Point to the front F, point the heat exchanger plates P1 and P2 on the two longitudinal edges 21 a Edge expression 23, which extends only over the length l of the heat exchanger plates P1 and P2 extends. In connection with FIG. 6 it can be seen that two heat exchanger plates P1 and P2 with their rear sides R placed against each other are and form within the flow channel 2, which over the Total length L goes. The heat exchanger plates P 1 and P2 are at their edge deformations 22 connected. On the front F of the heat exchanger plate P1 or P 2 is the next heat exchanger plate P1 or P2, which is also with the front F has been arranged, the heat exchanger plates P1; P2 are connected to their edge features 23 and the flow channels 3 train. Into these flow channels 3 extend into This embodiment knobs 20. The knobs 20 have the same height like the margins 23 and are otherwise arranged so that they with the knobs 20 on the adjacent heat exchanger plate P1 or P2 Touch to be connected as well.

Fig. 8 shows another embodiment in which the edge 21 of the heat exchanger plates P1 and P2 were simply folded over the entire length L. is, so that the heat exchanger plates P1 and P2 are nested one inside the other can be used to form the flow channels 2. Between these flow channels 2 is on both edges 21 each a rod 24, which is twice the height of Knobs 20 has. The length of the rods 24 corresponds to the length l, so that on in this way the flow channels 3 can be formed.

Another embodiment is shown in FIG. 9, which makes it clear that with regard to the flow through the heat exchanger realizes all possible variants are, whereby the proposed basic principle is not abandoned. in the There is a partition 19 for the exhaust gas 7. The inlet 14 and the outlet 15 are arranged on this collecting space 7, so that the exhaust gas for example via two flow channels 3 in the one on the opposite Side arranged deflection plenum 18 flow and after the deflection return to outlet 15 via the other two flow channels 3 can.

Without special representation it should be noted that of course also Such variants are very easily possible on the cooling water side, for example characterized in that the cooling water outlet 9 to the lower collecting space in the picture 4 is arranged, a partition plate is inserted in the collecting space 4 and on opposite end a comparable deflection collecting space for the cooling water is provided.

Another embodiment, not shown, has the inlet and outlet for the coolant on one side of the heat exchanger and the inlet and outlet for the exhaust gas on the opposite side of the heat exchanger.

List of reference numbers

1

Exhaust gas heat exchanger

2

longer flow channels

3

shorter flow channels

4

Storage room, cooling water

5

first tube sheet

6

second tube sheet

7

Collection room, exhaust gas

8th

Inlet, cooling water

9

Outlet, cooling water

10

Coat, collecting room 4

11

end plate

12

Board on tube sheet 5

13

interface

14

Intake, exhaust gas

15

Exhaust, exhaust

16

Opening, tube sheet 5

17

Openings, tube sheet 6

18

Deflection chamber, exhaust gas

19

separating plate

20

burl

21

Edge of the heat exchanger plates

22

Forming on the edge

23

Rand expression

24

rods

25

slats

P1; P2

heat exchanger plates

R F

Back, front of the panels

L

Length of the long flow channels

I

Length of the short flow channels, = area in which both channels run in parallel

Claims (12)

1. Heat exchanger, in particular exhaust-gas heat exchanger, consisting of a stack of heat exchanger plates (P1; P2) which form separate flow ducts (2, 3) running parallel to one another, with collecting spaces (7, 4) and with an inlet and outlet (8, 9, 14, 15) for the exhaust gas and for the preferably liquid cooling medium, characterized in that the flow ducts (2) for one medium, which are formed from heat exchanger plates (P1; P2), are longer (L) than the flow ducts (3) for the other medium and pass through the at least one collecting space (4) for this other medium, which has inlets and/or outlets (8; 9), and in that the heat exchanger (1) is designed without a housing in the region (I) in which both flow ducts (2; 3) run parallel to one another.
2. Heat exchanger according to Claim 1, characterized in that the collecting space (4) for the other medium is delimited by two tube sheets (5; 6) located opposite one another and is surrounded by a casing (10) on which the inlets and/or outlets (8; 9) are located.
3. Heat exchanger according to Claim 2, characterized in that the casing is formed by the rim (12) of one tube sheet (5), said rim forming with the rim of the other tube sheet (6) a connecting surface (13).
4. Heat exchanger according to Claim 2 or Claim 3, characterized in that the first tube sheet (5) has an orifice (16), in which the stack of heat exchanger plates (P1; P2) which has both flow ducts (2; 3) issues, and the second tube sheet (6) has orifices (17), in which the longer flow ducts (2) issue.
5. Heat exchanger according to one of the preceding claims, characterized in that the inlet (14) and the outlet (15) for the exhaust gas and/or for the cooling medium are arranged at opposite ends of the heat exchanger (1).
6. Heat exchanger according to one of Claims 1 to 4, characterized in that the inlet (14) and the outlet (15) for the exhaust gas and/or for the cooling medium are arranged on one side of the heat exchanger (1) and a deflecting collecting space (16) is provided at the opposite end.
7. Heat exchanger according to one of the preceding claims, characterized in that the heat exchanger plates (P1; P2), preferably at the longitudinal edges (21) located opposite one another, are formed, over the entire length of the plates, towards one plate side (rear side R) and have, over part (I) of the entire length (L), a pressed-out edge portion (23) towards the other plate side (front side F).
8. Heat exchanger according to one of the preceding claims, characterized in that the heat exchanger plates (P1; P2), lying rear side (R) to rear side (R), form the longer flow ducts (2) which have adjoining them heat exchanger plates (P1; P2), lying front side (F) to front side (F), which form the shorter flow ducts (3) which are again followed by heat exchanger plates (P1; P2) lying rear side (R) to rear side (R).
9. Heat exchanger according to one of the preceding claims, characterized in that the shorter flow ducts (3) are preferably cooling-water ducts and the longer ducts (2) are intended for the exhaust gas.
10. Heat exchanger according to one of Claims 2 - 9, characterized in that the outer ducts (3) are cooling-water ducts which are delimited in each case by a closing plate (11), one tube sheet (5) having an approximately rectangular orifice (16) in order to receive the stack of heat exchanger plates (P1; P2) having both flow ducts (2; 3) and to receive the ends of the closing plates (11).
11. Heat exchanger according to one of Claims 2 to 9, characterized in that the outer ducts (2) are exhaust-gas ducts, one tube sheet (5) having an orifice which, in the corners, has cutouts for the pressed-out edge portions (23) of the uppermost and lowermost heat exchanger plate (p1; p2), in order to receive the entire stack of heat exchanger plates. (p1; p2).
12. Heat exchanger according to one of Claims 1 to 6 and 9 to 10, characterized in that the heat exchanger plates (P1; P2) have at the edges (21) a bent portion extending over entire length (L) and are laid one in the other in a nest-like manner to form the flow ducts (2), and, to form the flow ducts (3), between the pairs of plates there are arranged bars (24), the length of which corresponds approximately to the length (I) of the shorter flow ducts (3).

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