EP1520148B1 - Device for heat exchange between flowable media - Google Patents

Abstract

The invention relates to a device for heat exchange between flowable media. Said device comprises a heat exchanger block which is defined, on one side, by an inflow chamber ( 1 ) for supplying the liquid medium, and on the other side, by an outflow chamber ( 3 ) for evacuating the liquid medium. Said block comprises fluid channels ( 7 ) for the liquid medium, extending through the block from the inflow chamber ( 1 ) to the outflow chamber ( 3 ), and a covering plate ( 9 ) which extends from the inflow chamber ( 1 ) to the outflow chamber ( 3 ) and closes the block at one end. Said covering plate ( 9 ) is provided with at least one inner passage ( 13 ) which extends from the inflow channel ( 1 ) to the outflow channel ( 3 ) as a bypass flow channel bypassing the fluid channels ( 7 ). Said passage can be blocked by means of at least one pressure limitation device ( 11 ), and unblocked by opening said pressure limitation device ( 11 ) as a result of a pressure difference between the inflow chamber ( 1 ) and the outflow chamber ( 3 ), which exceeds a pre-determined threshold value.

Description

The invention relates to a device for heat exchange between fluid media, of which at least one is in the liquid state.

Known devices (DE-A-196 51 988), which serve to influence the thermal state of a liquid flowing through them, are widely used in the art, in particular in the form of liquid / air coolers. When used in conjunction with hydraulic systems or manufacturing equipment where operating fluids such as hydraulic oil, lubricants or coolants are to be cooled by cooling air passing through the device, provision is made for malfunction or failure of the device due to temperature dependence of viscosity to avoid the liquid to be cooled. In order to optimize the efficiency of the heat exchange, in the fluid paths through which the liquid to be cooled flows within the device, usually turbulence generating blades or lamellae are arranged, which must be flowed around by the liquid, which is thereby swirled, so that all components of the liquid flow come into contact with the surrounding the fluid path walls for heat exchange.

The turbulence causing components cause a certain throttling of the liquid flow, so that between the input side Inflow chamber for the liquid to be cooled and the output side outflow chamber of the liquid builds up a dependent of the throttling differential pressure. In the case of liquids to be cooled, the viscosity of which is highly temperature-dependent, the correspondingly high viscosity of the liquid due to the throttling in the operating phases in which the liquid in question has a low temperature, for example during start-up phases in which the operating fluid in question is still cold Fluid paths of the device lead to excessive pressure increase. In order to avoid such overpressures that could lead to disturbances or damage, usually a bypass device between inflow and outflow chamber of the device is provided, which is normally closed, but has a pressure limiting device, which allows the secondary flow of the liquid until, when the Cooling liquid has reached its operating temperature and the viscosity has decreased accordingly, the differential pressure at the device has dropped to a safe value, in which the secondary flow is blocked and the liquid flows through only the fluid paths for the heat exchange.

From DE-A-41 06 963 a cooling device for fluid media is known, in particular water cooler for oil-operated hydraulic systems and internal combustion engines, in which the medium to be cooled II is brought under heat exchange in indirect contact with the cooling medium I, with a per se known oil-air cooler with connection piece for the inlet and outlet of the medium II in a heat sink having a plurality of spaced, parallel cooling channels, the interstices are filled with fins, through which the medium flows through 1 turbulent and at the with the Connection piece provided longitudinal sides a lid is provided, which in the region of the connection piece is fastened and has internal and external seals, and with an approximately hollow cuboid cast body with a plurality of chambers and nozzles for the inlet and outlet of the medium I, in which the oil-air cooler is inserted and fixed substantially form-fitting manner such that in use the outer edge of the lid over a seal sealingly rests on the housing edge.

This results in a cost-effective cooling device for fluid media with improved heat exchange; However, especially at the mentioned start-up phases, in which the liquid in question has a lower temperature and thus, if appropriate, a high viscosity, overpressures and thus damage to the known cooling device may occur.

From DE 42 32 366 A a generic device for heat exchange between fluid media is known, of which at least one is in a liquid state, with a heat exchanger block, on one side by an inflow and on the opposite side by a discharge chamber for supply or the discharge of the liquid medium is limited, the fluid paths for the liquid medium, which extend through the block from the inflow to the outflow chamber and are separated by flow paths located therebetween for the passage of the other flowable medium, and a cover plate having overlapping the fluid paths and flow paths extending from the inflow chamber to the outflow chamber and terminating the block at one end, the cover plate having at least one inner passageway, the fluid paths immediately as Nebenstromkanal from the inflow to the outflow first extends, by at least one pressure limiting device lockable and by opening the device due to a prevailing between inflow and outflow chamber, a predetermined threshold exceeding pressure difference is releasable.

According to one embodiment of the known solution, the oil cooler is formed einflutig, so that when the oil has operating temperature and is to cool instead of a bridging line in the cover plate of the radiator, the oil in the return flow through the other fluid paths within the heat exchanger block from the inflow towards Outflow chamber is guided out. Accordingly, all fluid paths of the tube bundle of the heat exchanger block are flowed through in one direction by the oil. In another zweifluidigen embodiment, a tube bundle of the heat exchanger block allows the flow of oil supplied via an oil inlet from the outflow chamber in the direction of the inflow chamber, which serves as a reversing chamber and another second tube bundle allows the return of the oil from the inflow chamber back to the outflow chamber and from there to an oil outlet. For separating the fluid flows serves a partition wall within the outflow chamber, which separates them so far in about the same size sub-chambers.

Based on this prior art, the invention has the object, while maintaining the advantages in the prior art, the known devices further improve to the effect that they are characterized by a particularly simple structure that can be implemented easily and inexpensively, and yet To a great extent a functionally reliable use is achieved at a wide variety of temperatures of the medium to be cooled.

According to the invention this object solves a device having the features of claim 1 in its entirety.

The apparatus according to the invention comprises a heat exchanger block in which the fluid paths for the heat exchange fluid extend between an inflow chamber bounding the block on one side and an outflow chamber bounding the block on the opposite side; wherein fluid paths and flow paths for passing the other fluid medium, such as the cooling air, alternate with each other, i. in the block on each other. As the upper end of the block a cover plate is provided. Characterized in that according to the characterizing part of claim 1, the cover plate has two through channels, the fluid paths immediately, extend as bypass channels from the inflow to the Auströmkammer, the respective passage depending on the pressure difference between inflow and outflow chamber by means of a pressure limiter lockable or releasable , According to the invention therefore provided as a safety device against a build-up of excess pressure respective bypass device is integrated in the cover plate of the heat exchanger block. This leads to a substantial simplification of the structure of the device, which is simple and inexpensive to produce in aspired.

The preparation of the device is particularly simple, which is provided as a cover plate, a portion of a hollow profile body formed by extrusion in the form of a flat tube, which is closed at both ends by a closure plate. In this case, the strand of the flat tube forming hollow profile body is extruded so that the flat tube has the two inner through channels. The wall of the flat tube is provided with appropriate Durchgansgbohrungen that allow in the end regions of each passage channel fluid communication to the inflow and outflow chamber, wherein for each passage of the flat tube at least ever seen a pressure relief device before. These are each arranged in one of the through holes in the flat tube.

In the apparatus, the respective pressure limiting device may also consist of a controlled by pressure and / or temperature closing part, for example in the form of a temperature-dependent expansion element. If the medium to be cooled is cold, it also builds up a correspondingly high pressure in the device and the pressure limiting device has to release the bypass function of the cooler. If the temperature of the medium to be cooled then increases and is thus highly fluid, it can flow directly through the cooler, bypassing the bypass function, in which the closing part closes the bypass at a higher temperature. A pertinent closure part can be realized, for example, by an expansion element and the bypass device according to the invention can also be subsequently connected to existing radiators.

In a preferred embodiment, a check valve in the form of a spring-loaded poppet valve is provided as a pressure limiting device for each passage.

In the manufacture of the heat exchanger block, the fluid paths and the flow paths forming components can each be superposed to form a block with a desired number of elements are soldered, at the same time forming the Nebenströmeinrichtung Cover plate can be fixed at the top of the block by soldering.

A particularly simple construction results when the cover plate forming flat tube is connected at the ends of the passageway or the passageways through a closure plate, which is soldered when soldering the heat exchanger block with. When the closure plates extend beyond the ends of a plurality of passageways, the closure plates preferably have a passage formed therein allowing fluid communication between the passageways. This passage may be formed by an elongated recess formed in the closure plates and extending over the ends of the passageways located in the flat tube.

• Fig. 1 eine stark schematisch vereinfachte Darstellung eines Ausführungsbeispieles der erfindungsgemäßen Vorrichtung in Form eines Luft/Flüssigkeits-Kühlers;
• Fig. 2 eine lediglich zur Verdeutlichung der Fluidströmung im Ausführungsbeispiel gedachte Schemaskizze der Nebenstromeinrichtung des Ausführungsbeispieles mit zugeordneten Druckbegrenzungseinrichtungen;
• Fig. 3 eine Schnittdarstellung eines zweizügigen Flachrohres der Nebenstromeinrichtung des Flachrohres, entsprechend der Schnittlinie III/III von Fig. 1 und
• Fig. 4 eine Draufsicht der Innenseite einer Verschlußplatte für den endsetitigen Abschluß des in Fig. 3 gezeigten Flachrohres.

The invention with reference to an embodiment shown in the drawing is explained in detail. Show it:

• Figure 1 is a highly simplified schematic representation of an embodiment of the device according to the invention in the form of an air / liquid cooler.
• FIG. 2 is a schematic diagram of the secondary flow device of the exemplary embodiment with associated pressure limiting devices, intended merely to illustrate the fluid flow in the exemplary embodiment; FIG.
• Fig. 3 is a sectional view of a zweizügigen flat tube of the bypass device of the flat tube, corresponding to the section line III / III of Fig. 1 and
• Fig. 4 is a plan view of the inside of a closure plate for the endsetitigen completion of the flat tube shown in Fig. 3.

In Fig. 1, which shows a highly simplified schematic representation of an embodiment of the invention in the form of a liquid / air cooler in block design, are an inflow chamber for the supply of the liquid to be cooled and an outflow chamber for dispensing the liquid with 1 and 3 respectively designated. Between inflow chamber 1 and outflow chamber 3, the heat exchanger block has alternating, superimposed heat exchange elements plate-shaped, namely fluid guide body 5, the inner fluid paths 7 contain, through which flows the liquid to be cooled from the inflow chamber 1 to the outflow chamber 3, and grid body 8, form the flow paths for cooling air flowing therethrough, the cooling fins of the grid body 8 sweeps. The fluid guide body 5 and the grid body 8 are plate-like components with a square or rectangular outline.

The heat exchanger block with lateral inflow chamber 1 and lateral outflow chamber 3 and the stack of fluid guide bodies located between them 5 and grids 8, which components are all soldered together, is completed at the top by a cover plate 9, which is also soldered. This cover plate 9 forms a bypass device for a fluid connection between inflow chamber 1 and outflow chamber 3, bypassing the fluid paths 7 in the fluid guide bodies 5, see the in Fig. 1 and 2 double-line drawn flow arrows, the inflow of liquid from the inflow chamber 1 in the cover plate. 9 and illustrate the flow of liquid from the cover plate 9 in the outflow chamber 3 via spring-loaded ball check valves 11.

The normally closed by spring load check valves 11 form a pressure limiting device which releases the liquid flow when the pressure difference between inflow chamber 1 and outflow chamber 3 exceeds a preselected by adjustment of the valve spring force threshold. In Fig. 1, only a check valve 11 is shown. In the interest of a valve passage cross-section of the desired size, however, a plurality of check valves 11 are provided in the present embodiment, as can be seen from Fig. 2, seen with respect to FIG. 1 vertical viewing direction, the fluid flow of the cover plate 9 formed by the bypass device 11 through the check valves , d. H. in the outflow chamber 3, illustrates.

The cover plate 9 is, as can be seen from Fig. 3, formed by a strand portion of an extruded hollow body profile in the form of a flat tube, which is zweizügig in the present example, that has two inner through-channels 13. Both ends of the cover plate 9 forming flat tube are completed by a respective closure plate 15 which in Fig. 4 is shown in more detail. Through holes in the wall of the cover plate 9 forming flat tube form the fluid connection between inflow chamber 1 and the inner passageways 13 and the fluid connection of the passageways 13 with the outflow chamber 3. The inflow chamber 1 associated through holes, of which in Fig. 1 only one is visible, are designated 17. The outflow chamber 3 associated through holes are designated 19. According to the number of two through-channels 13 provided in the exemplary embodiment, two through-holes 17 are provided on the inflow chamber 1 and two through-holes 19 on the outflow chamber 3 in the present example.

As can be seen from FIG. 2, a check valve 11 is arranged in each through-bore 19 in order, as already indicated above, to achieve a sufficiently large valve passage cross-section without having to use excessively large valves. In order to allow at the ends of the cover plate 9 forming flat tube fluid communication between the two passageways 13, the shutter plates 15 are provided with an incorporated, recessed, elongated groove 21. When shutter plates 15 are soldered to cover plate 9 at the ends of passageways 13, groove 21 extends over the ends of both passageways 13, as can be seen in comparing FIGS. 3 and 4, thereby forming a passageway providing fluid communication between the passageways 13 produces at both ends.

In order to allow access to the non-return valves 11 serving as a pressure limiting device in the finished state of the device, access holes 23 are formed in the wall of the flat tube forming the cover plate 9 and corresponding to the respective non-return valve 11 1 and 3. As can be seen from FIG. 1, the access bores 23 can be locked by a closure part 25, which may be a screwed-in cover part or the like.
In a non-illustrated embodiment of the device, the respective pressure-limiting device 11 may also consist of a controlled by pressure and / or temperature closing part, for example in the form of a temperature-dependent expansion element. If the medium to be cooled is cold, it also builds up a correspondingly high pressure in the device and the pressure limiting device 11 has to release the bypass function of the cooler. If the temperature of the medium to be cooled then increases and is thus highly fluid, it can flow directly through the radiator, bypassing the bypass function, in that the closing part closes the bypass at a higher temperature. A pertinent closure member can be realized, for example, by an expansion element accordingly.

The bypass device according to the invention can also be subsequently connected to existing radiator, since preferably the bypass device has a height which corresponds to a fluid channel 7 and a subsequent lamellar channel 8 in the overall height. Thus, if one removes the pertinent upper lamella row together with the fluid channel in the case of an already delivered cooling device, then the space-standardized bypass device is retrofitted and welded, so that retrofitting with the bypass device is readily possible without the cooling capacity of the thus converted cooling device would be substantially reduced.

Claims (6)

1. Means for heat exchange between flowable media, of which at least one is in a liquid condition, with a heat exchanger block limited on one side by an inlet chamber (1), and on the opposite side by an outlet chamber (3) for the supply, i.e. removal of the liquid medium, comprising fluid paths (7) for the liquid medium, which extend through the block from the inlet chamber (1) to the outlet chamber (3), and separated by flow paths (8) for the conveying of the other flowable medium located between the same, as well as a cover plate (9) which extends from the inlet chamber (1) to the outlet chamber (3) covering the fluid paths (7) and flow paths (8) and closes off the block at one end, whereby the cover plate (9) comprises at least one inner passage channel (13) which extends as a by-pass channel from the inlet channel (1) to the outlet channel (3) whilst by-passing the fluid paths (7) through at least one pressure limiting device (11), lockable and releasable by means of a pressure difference exceeding a pre-determined limit value existing between the inlet chamber (1) and the outlet chamber (3), characterised in that a section of a hollow profile body in the form of a flat pipe (9) created by means of extruding is envisaged as the cover plate (9), the same being closed off at both ends by a closure plate (15), and in that passage bores (17, 18) are formed in the wall of the flat pipe (9), i.e. in the end sections of the same adjacent to the inlet chamber (1) and the outlet chamber (3), which form a fluid connection between the at least one passage channel (13) of the flat pipe (9) and the inlet chamber (1) and the outlet chamber (3), and in that the flat pipe (9) comprises two inner passage channels (13), each of which in connected with the inlet chamber (1), i.e. the outlet chamber (3) via the passage bores (17, 19), and in that at least one pressure limiting device (11) each is envisaged for each passage channel (13) of the flat pipe (9), and in that the pressure limiting device (11) for each passage channel (13) is located in a passage bore (17, 19) penetrating the wall of the flat pipe (9), and in that the pressure limiting devices (11) are each envisaged in the passage bores (19) connecting the passage channel (13) with the outlet chamber (3).
2. Means according to Claim 1, characterised in that a non-return valve (11) each in the form of a spring loaded seat valve is envisaged as the pressure limiting device.
3. Means according to Claim 1 or 2, characterised in that an access bore (23) enabling access to the valve (11) is envisaged in the wall of each passage channel (13) in the area opposite the non-return valve (11), the same being closable by means of a closure part (25).
4. Means according to one of the Claims 1 to 3, characterised in that a passage (21) forming a fluid connection between the passage channels (13) is formed in the closure plates (15) closing off the ends of the flat pipe (9).
5. Means according to Claim 4, characterised in that the passage in the closure plates (15) is formed by a longitudinal recess (21) inserted into the same which extends across the ends of the passage channels (13) located in the flat pipe (9).
6. Means according to one of the Claims 1 to 5, characterised in that the relevant pressure limiting device (11) consists of a closure part being controlled by pressure and/or temperature.

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