ES2397882A1 - Heat exchanger with stacked plates - Google Patents

Abstract

The exchanger has an assembly of stacked plates (2) defining independent circuits between which a fluid e.g. exhaust gas, to be cooled and a coolant circulate in alternate layers. A fluid circuit has a U configuration such that inlet and outlet of the fluid occupy adjacent positions at a same open end of the assembly of stacked plates. The plates define forward and return channels. The plates include a mounting flange coupled to the end. A separation unit i.e. dividing wall (7), separates input stream and output stream of the fluid. The separation unit is secured to the flange.

Description

HEAT EXCHANGER OF STACKED PLATES

The present invention relates to a stacked plate heat exchanger.

The invention especially applies to all types of heat exchangers within the scope of the engine, especially applies to exhaust recirculation exchangers of an engine (Exhaust Gas Recirculation Coolers or EGRC),

10 BACKGROUND OF THE INVENTION

The current configuration of the EGR exchangers on the market corresponds to a metal heat exchanger generally made of stainless steel or aluminum.

15 Basically, there are two types of EGR heat exchangers: a first type consists of a housing inside which a bundle of tubes is arranged for the passage of gases, the refrigerant circulating through the housing, externally to the tubes, and the second type consists of a series of parallel plates that constitute the heat exchange surfaces, so that the exhaust gases and the refrigerant circulate

2 Or between two plates, in alternating layers, and may include fins to improve heat exchange. In the loop of the recirculation system there is also an EGR valve that controls the passage of exhaust gases through the heat exchanger. Some stacked plate exchangers are known in which

2 5 each plate includes a longitudinal side closing wall, each pair of plates being mounted with their respective side walls arranged at the longitudinal ends for the separation and closing of the circuits of the gases and coolant fluid. Likewise, each circuit can be linear, also called

3 O in the form of "I", in which the fluid inlet and outlet are arranged at opposite ends; or it can be in the form of a "U" in which the fluid inlet and outlet are disposed adjacent at the same open end, the opposite end being closed, and defining a forward passage and a return passage through the channels of the plates. In the latter case, the closed end for the return of

3 5 fluid usually consists of a closed tank.

There are two possible "U" configurations in stacked plate EGR exchangers:

to)

Vertical "U" configuration: the gas flow is directed through

all the channels of the gas circuit of half of the plates,

5

and is returned by other channels of the gas circuit belonging to the

rest of completely different plates.

b)

Horizontal "U" configuration: the gas flow is directed through

of half of the channels of all the plates, and is returned by the

another half of the gas circuit channels belonging to them

10

plates.

Most of the components of the EGR exchangers are metallic, so that they are assembled by mechanical means and then welded in an oven or welded by arc or laser to ensure adequate sealing

15 required for this application.

In some cases, the EGR exchanger may also include some components made of plastic, which can perform a single or several functions manufactured in a single piece.

The main function of the EGR exchangers is the exchange of

2 Or heat between the exhaust gases and the cooling fluid, in order to cool the gases. Additionally, the EGR exchangers have to fulfill other secondary functions such as the assembly with the engine block, the connection with the coolant fluid, or the connection with the gas exhaust circuit.

In all these cases, the manufacturing process requires a large number of welding joints in the furnace or arc or laser welding, and consequently results in a complex and high-cost operation.

In stacked plate heat exchangers, it is necessary to close two different circuits: hot fluid and cold fluid. Usually, this type of heat exchanger is manufactured by oven welding.

3 O To avoid high pressure drops, fluids enter the heat exchanger directly. It is not possible to use pipes, so typical solutions consist of using tanks or accessories to insert the fluid into the heat exchanger.

The assembly and welding in this type of interfaces with the 3 5 stacked plates can cause quality problems, that is, leaks, so it is necessary that both refrigerant and gas circuits are properly closed to avoid possible leaks.

For the overall concept of efficiency, it is very important, in "U" configurations, that the hot gas flow does not mix with the cold gas flow 5. Of course, the gas inlet flow should never go directly through the

gas outflow.

Because the market tends to reduce the size of the engines, and the application of EGR heat exchangers not only in high pressure (HP) applications but also in low pressure (LP) applications, the space available for the

1 O exchanger and its components is getting smaller. The environments where the EGR exchanger must be integrated are increasingly complicated. Thus, it is important to develop compact EGR exchangers provided with integrated parts that can be placed in the available space.

15 DESCRIPTION OF THE INVENTION

The objective of the stacked plate heat exchanger of the present invention is to solve the drawbacks of the exchangers known in the art, providing a reduction or elimination of the proportion

2 O of the inlet flow of the fluid to be cooled that does not enter the exchanger and is introduced directly with the outflow of the fluid to be cooled in exchangers with a "U" configuration.

The Stacked Plate Heat Exchanger, object of the present invention, comprises a plurality of stacked plates between which the fluid to be cooled and the cooling fluid circulate between two independent circuits defined by said plates, in alternating layers, including the circuit of the fluid to be cooled in a "U" configuration in which the inlet and outlet of said fluid to be cooled are arranged adjacent at the same open end of the stacked plate assembly, the opposite end being closed, and said plates defining channels

3 O one way and some return channels, and comprising a clamping flange coupled at said open end, and is characterized by the fact that it comprises means for separating both inlet and outlet flows of the fluid to be cooled, and said means being of separation integrated in said clamping flange. In this way, the separation means allow to integrate the function

3 5 closing between the inlet and outlet flow of the fluid to be cooled, so they act

as a separating barrier between the inlet and outlet flow of the fluid to be cooled, and also avoid as much as possible the flow bypass between said inlet and outlet. Advantageously, said separation means include a barrier-like wall coupled to the external face of the clamping flange, said wall being

5 capable of dividing the inlet and outlet area of fluid to be cooled in said open end of the set of stacked plates. Therefore, said wall must be adapted to the design of the plates in each configuration.

Also advantageously, said separating wall is capable of coming into direct contact with a plug or flap of an EGR valve for the 1O closing of both inflows and outflows of the fluid to be cooled through the

exchanger

Therefore, since said wall is integrated in the external part of the flange, it also performs the function of interface between the exchanger and the EGR valve or pipe,

Preferably, said wall can be an independent piece coupled to the flange or it can be manufactured in a single piece integrated with the flange. Also, the flange configuration may vary depending on the configuration of the EGR exchanger. According to an embodiment of the invention, in which the

2 O exchanger is of the vertical "U" configuration type, where the flow of fluid to be cooled is directed through all of the channels of the fluid circuit to be cooled from half of the plates, and is returned by other channels of the fluid circuit to be cooled belonging to the rest of completely different plates, is characterized by the fact that the separating wall is integrated in the flange in a

2 5 position substantially horizontal and welded in the oven to an intermediate plate designed to separate both inlet and outlet flows of the fluid to be cooled. According to another embodiment of the invention, in which the exchanger is of the horizontal "U" configuration type, where the flow of fluid to be cooled is directed through half of the channels of the entire plate, and is

3 Or returned by the other half of the channels of the fluid circuit to be cooled belonging to the same plates, it is characterized by the fact that the separating wall is integrated in a substantially vertical position and oven-welded to the plates in a planned intermediate position to separate both inflows and outflows of the fluid to be cooled.

Advantageously, in the realization of the "U" configuration

horizontally, the separating wall comprises housings that can be fitted at the ends of the plates.

In this way, this coupling joint allows the possible internal bypass to be minimized, which improves the heat efficiency of the exchanger. 5 Also, the wall is in direct contact with the plates for welding in the oven

with said plates, and with fins or disturbers to reduce the possible bypass. Preferably, the exchanger comprises a gas tank coupled to the closed end of the stacked plate assembly.

10 BRIEF DESCRIPTION OF THE DRAWINGS

In order to facilitate the description of what has been stated above, some drawings are attached in which, schematically and only by way of non-limiting example, two practical cases of realization of the

15 stacked plate heat exchanger of the invention, in which: Figure 1 is a perspective view of the stacked plate assembly showing the separating wall integrated in the flange, for an EGR heat exchanger of vertical "U" configuration , according to a first embodiment of the invention;

Figure 2 is a perspective view of the set of stacked plates 2 O according to Figure 1, showing the gas inlet and outlet flow, and the possible bypass between said flows; Figure 3 is a perspective view of the mounted heat exchanger, according to Figure 1; Figure 4 is a front view of the mounted heat exchanger, 2 5 according to Figure 1;

Figure 5 is a perspective view of the stacked plate assembly showing the separating wall integrated in the flange, for an EGR heat exchanger of horizontal "U" configuration, according to a second embodiment of the invention;

3 Or Figure 6 is a perspective view of the set of stacked plates according to Figure 5, showing the gas inlet and outlet flow, and the possible bypass between said flows;

Figure 7 is an enlarged view of the separating wall showing the connection fittings with the plates, according to the exchanger of Figure 5; 3 5 Figure 8 is a perspective view of the heat exchanger

assembled, according to figure 5; and Figure 9 is a front view of the mounted heat exchanger, according to Figure 5.

5 DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to Figures 1 to 4, the heat exchanger 1 EGR comprises a plurality of stacked plates 2 between which the gas to be cooled and the cooling fluid circulate between two independent circuits defined by

1 Or said plates 2, in alternating layers. Each plate 2 includes a longitudinal closing side wall 3, as can be seen in Figures 1 and 2, each pair of plates 2 being mounted with their respective side walls 3 arranged at the longitudinal ends for separation and closing of the circuits. .

15 The exchanger 1 also includes a housing 4 provided to house inside the set of stacked plates 2, as can be seen in Figures 3 and 4, as well as a clamping flange 5 coupled at said open end and a gas tank 6 at said closed end. Also, the configuration of the flange 5 may vary depending on the configuration of the exchanger l.

2 O In this case, the circuit of the gas to be cooled includes a "U" configuration in which the inlet and outlet of the gases are arranged adjacently at the same open end of the stacked plate assembly 2, the opposite end being closed, and said plates defining one way channels and some return channels. The exchanger 1 also comprises a wall 7 by way of

2 5 barrier for the separation of both flows of inlet and outlet of the gases, said wall 7 being integrated in the clamping flange 5. In addition, said wall 7 can be a separate piece coupled to the flange 5 or it can be manufactured in a single piece integrated with the flange 5.

There are two possibilities of "U" configurations, horizontal or 3 O vertical, on stacked plate EGR exchangers, as will be explained below.

A first embodiment of the invention is shown in Figures 1 to 4, in which the exchanger 1 is of the vertical "U" configuration type, that is, the flow of the gases is directed through all the channels. of the circuit of

3 5 gases from half of plates 2, and is returned by other channels of the circuit of the

gases belonging to the rest of completely different plates 2.

In this case, the separating wall 7 is integrated in the flange 5 in a substantially horizontal position and welded in the oven to an intermediate plate 2a intended to separate both inlet and outlet flows of the gases.

5 In this way, the separation wall 7 allows the closing function to be integrated between the inlet and outlet flow of the gases, thus acting as a separating barrier between the inlet and outlet flow of the gases, and also prevents as possible the flow bypass between said input and output.

In Figure 2, the direction of the 1 O flow of gases in and out has been illustrated by white arrows, and by means of a black arrow the possible bypass between these flows.

Said separating wall 7 is coupled to the external face of the clamping flange 5, said wall 7 being able to divide the area of entry and exit of the gases at said open end of the set of stacked plates 2. Therefore, said wall

15 7 must be adapted to the design of the plates 2 in each configuration. Furthermore, said separating wall 7 is capable of coming into direct contact with a plug or flap of an EGR valve (not shown) for closing both inlet and outlet gas flows through the exchanger l. Therefore, said wall 7 being integrated in the external part of the

2 Or flange 5, also performs the interface function between exchanger 1 and valve

or EGR pipe

A second embodiment of the invention is shown in Figures 5 to 9, in which the exchanger 1 'is of the horizontal "U" configuration type, that is, the gas flow is directed through half of the channels of all

2 5 plates 2, and is returned by the other half of the gas circuit channels belonging to the same plates 2. In this case, the separating wall 7 is integrated in a substantially vertical position and welded in the oven to the plates 2 in an intermediate position provided to separate both inlet and outlet flows from the gases.

3 O In the same way, in figure 6 the direction of the gas inlet and outlet flow has been illustrated by white arrows, and by means of a black arrow the possible bypass between these flows.

Furthermore, in this embodiment of the horizontal "U" configuration, the separating wall 7 comprises housings 8 capable of being fitted in 3 5 the ends of the plates 2, as can be seen in Figure 7.

In this way, this fitting by fitting allows the possible internal bypass to be minimized, which improves the thermal efficiency of the exchanger l. Also, the wall 7 is in direct contact with the plates 2 for welding in the oven with said plates 2, and with fins or disturbers (not shown) for

5 reduce the possible bypass.

On the other hand, in both embodiments, the housing 4 includes two lateral reservoirs 4a joined together to receive the lateral flow of cooling fluid in and out of the stack of stacked plates 2, as shown in Figures 3 and 8 .

10 The exchanger 1 also comprises an inlet 9 and an outlet 1O of the cooling fluid disposed on opposite sides of the housing 4, as can be seen in Figures 4 and 9. This design of side plates 2 can allow the lateral connection of wells 9,10 of the cooling fluid, to provide the exchanger 1 with

The distribution of lateral coolant fluid flow, which has many benefits for integrating an EGR heat exchanger of stacked plates 2 into a small or complicated space around the engine block.

Claims (7)

l. Stacked plate heat exchanger (1), comprising a

plurality of stacked plates (2) between which the fluid to be cooled circulates and the

5

refrigerant fluid between two independent circuits defined by said plates (2),

in alternating layers, including the fluid circuit to cool a configuration

in "U" in which the inlet and outlet of said fluid to be cooled are arranged

adjacent at the same open end of the stacked plate assembly, the

opposite end closed, and said plates (2) defining one-way channels and about

1 o

return channels, and comprising a clamping flange (5) coupled in said

open end, characterized by the fact that it comprises separation means

(7) of both inflows and outflows of the fluid to be cooled, and said

separating means (7) integrated in said clamping flange (5).

2. Exchanger (1) according to claim 1, wherein said

fifteen

separation means include a barrier wall (7) coupled to the face

external of the clamping flange (5), said wall (7) being able to divide the

fluid inlet and outlet area to be cooled at said open end of the assembly

of stacked plates (2).

3. Exchanger (1) according to claim 2, wherein said wall

2 o

separator (7) is capable of coming into direct contact with a shutter or flap

of an EGR valve for closing both inlet and outlet fluid flows to

refrigerate through the exchanger (1).

4. Exchanger (1) according to claim 2 or 3, wherein said

wall (7) is an independent part coupled to the flange (5) or is manufactured in

2 5

a single piece integrated with the flange (5).

5. Exchanger (1) according to any one of claims 2 to

4, of the vertical "U" configuration type, where the flow of fluid to be cooled is

directed through all the channels of the fluid circuit to be cooled from the

half of the plates (2), and is returned by other channels of the fluid circuit to

3 o

refrigerate belonging to the rest of completely different plates (2), characterized

by the fact that the separating wall (7) is integrated in the flange (5) in a

substantially horizontal position and welded in the oven to an intermediate plate (2a)

intended to separate both inlet and outlet flows of the fluid to be cooled.

6. Exchanger (1) according to any one of claims 2 to

3 5

4, of the horizontal "U" configuration type, where the flow of fluid to be cooled is

directed through half of the channels of all the plates (2), and is returned

through the other half of the channels of the fluid circuit to be cooled belonging to the

same plates (2), characterized by the fact that the separating wall (7) is

integrated in a substantially vertical position and oven-welded to the plates (2) in

5

an intermediate position intended to separate both input and output flows from the

fluid to cool.

7. Exchanger (1) according to claim 6, wherein the wall

separator (7) comprises housings (8) capable of being fitted in the

plate ends (2).

1 o

8. Exchanger (1) according to claim 1, comprising a

gas tank (6) coupled to the closed end of the stacked plate assembly

(2).