DE102012022046A1 - Heat exchanger installed in e.g. internal combustion engine of motor vehicle, has stack of plates in between which flow channels are arranged, while outlet channels are connected to outlet media - Google Patents

Abstract

The heat exchanger has stack of plates (2) in between which flow channels are arranged, while outlet channels (5-8) are connected to outlet media. Several protrusions (21) are extended into flow channels with respect to plate planes (20), and protrusions (23) are located diametrically around the protrusions (21) at defined distance (12). A vertical distance between the plates is calculated, and aligned holes are formed around outlet channels.

Description

The invention relates to a heat exchanger having a stack of plates having localized formations which project into flow channels disposed between the plates which are hydraulically connected to inlet and outlet channels formed vertically through the plate stack and formed from aligned holes in the plates are.

A heat exchanger of this kind is for example from the EP 1 612 499 A2 known. The known plate heat exchanger achieves a considerable internal pressure stability, without having to provide separate turbulators in the flow channels. Thus, resulting from the processing or the manufacture of the turbulators resulting metal chips that adhere to the turbulators and could get into the oil circuit. The known plate heat exchanger is therefore designed as an oil cooler.

From the JP 2001-099 588 A a plate heat exchanger is known as an evaporator. The plates have formations which are formed in the known herringbone pattern, which extends undulating over the entire plates. According to this document, known evaporators have, inter alia, the problem that condensate forms between a flat cover plate and an adjacent, provided with the wave-shaped formations heat exchanger plate, which can freeze there. For the described area (cover plate / heat exchanger plate) then a modified construction is proposed, which should solve the icing problem.

It has certain advantages to use pure water as a working medium in an energy recovery plant, which is conveyed in a thermodynamic cycle through the plant and thereby cycled and condensed. Pure water, ie water without antifreeze, to use as a working medium, is also known to have a significant drawback, which consists in the formation of ice at lower temperatures. As a result, the components of the circuit or plant can be destroyed.

To remedy this situation, there are also suggestions to empty the system during longer rest periods on the working fluid side to avoid the formation of ice. Often this is not completely successful because it is an externally closed system and / or it requires too much effort.

In addition, heat exchangers are known from the prior art, which prevent destruction of the same by ice formation, at least to prevent it within certain temperature limits. Here are often flexible partitions or the like, which, as in the DE 32 27 206 C2 , are also formed wavy over a large area in order to increase their surface area and to increase their elasticity, brought to use.

The object of the invention is the development of a heat exchanger, which is to achieve a good heat exchange efficiency and internal pressure stability and reduces the risk of destruction of the heat exchanger by ice formation.

This object is achieved by a heat exchanger having the features of claim 1.

Significant design features of the heat exchanger according to the invention according to claim 1 are that first of the local formations extend into the flow channels for the one of the media, where they have a - relative to the plate planes - vertical distance, either from each other or to an opposite plate portion, and a pair of second local formations are arranged around the first local formations, either two of the second local formations being connected diametrically to each other or one of the second local formations being connected to a diametrical plate section.

A non-preferred alternative design of the heat exchanger differs essentially from the preferred alternative in that the first local formations - as mentioned - have a vertical distance to an adjacent plate portion. In the preferred alternative, however, the vertical distance is in each case between two first local formations pointing in a flow channel.

The first two local formations form a pair. The second local formations are preferably arranged in pairs. They are in contrast to the first local forms connected.

Both alternatives can also be realized on a single heat exchanger, which means that the two alternatives are miscible with each other.

In the operating condition of the plant containing the heat exchanger according to the invention, the mentioned vertical distance between the first local formations or between the first local formations and the adjacent plate bottom portion is present.

In the case of ice formation, which occurs at a correspondingly low temperature when the system is at rest, the first formations lie diametrically opposite one another or on a flat plate bottom section of the adjacent plate and thus, together with the group of interconnected second local formations, allow the space expansion just required in the flow channels, whereby the destruction of the heat exchanger is prevented.

The first localized formations as well as the flock of second localized formations disposed around the first localized formations act as turbulence generators in the flow channels. Therefore, the heat exchanger is also advantageously used where it is not the solution of the above task but other problems are in the foreground.

In a plate capacitor, the one medium is a coolant, for example the coolant of an internal combustion engine and the other medium is a working fluid to be condensed, for example water, which essentially enters the condenser as vapor and leaves the condenser as water ,

In an evaporator, it is known that corresponding to water which exits as vapor. The one medium is in this case no coolant, but hot exhaust gases, such as those of an internal combustion engine.

Local formations within the meaning of the proposal are localized depressions and / or localized elevations in the plates, which - in contrast to fully corrugated plates - are surrounded by flat, ie non-deformed, plate sections.

The local formations may be circular knobs or have any polygonal shape.

The first local formations arranged with the vertical distance as well as the second local formations can be of the same or different shape. Ideally, but not necessarily, the first local formations and also the second local formations are congruently superimposed. However, some offset is allowed. Ideally, the first formations and also the second formations have an identical cross section.

A permissible room size is about 9%. It should be in the elastic range, so it should be able to regress again. The direction of spatial expansion is perpendicular to the planes of the plates. As a material is a metal into consideration, for example, aluminum or a suitable stainless steel.

The risk of icing on the coolant side is not given in the here play a role temperature range per se, since it is the coolant, for example, the cooling liquid of an internal combustion engine, which contains known additives that prevent ice formation.

The invention, in its preferred embodiment - as one of several differences from the prior art described above - provides a plate heat exchanger in which all plates of the plate stack have localized first and second formations which are localized depressions and localized elevations Appear appearance. The EP 1 612 499 A2 However, this training has only every second plate of the disk stack.

Another preferred embodiment of the invention provides that some of the plates have localized elevations and others of the plates have localized depressions, with the plates in the plate stack alternating with the depressions and the plates with the elevations. The said EP'499, however, has plates with recesses and elevations, as already mentioned above, as well as other plates which have only depressions.

The invention provides with simple structural features for the working fluid a limited space expansion at the expense of a limited space reduction on the coolant side. The coolant is pushed back into the circuit by the space reduction. The working fluid can therefore freeze at lower temperatures and thereby naturally expand, but without destroying the heat exchanger.

However, in order to allow a space expansion in both flow channels, ie in the flow channels for the one and in the flow channels for the other medium, it can also be provided that the pairs of first local formations comprise at least one pair consisting of a recess in the one plate and a protrusion in the other plate, and at least one further pair formed from a protrusion in the same one plate and a recess in the same other plate. These depressions and elevations have the mentioned vertical distance from each other. The pairs are also relatively close to each other, as viewed in the direction of the plate planes, and form the center for the flock of second local formations.

Further features of the invention are the subject of the dependent claims, which are to be regarded as detailed here at this point.

In addition, all features and their effects will become apparent from the following description of embodiments made with reference to the accompanying drawings.

Brief Description

1 - sketch of a plate of the plate stack;

2 - Section of a plate stack in the operating state and 2a Resting state with ice formation;

3 - Operating state and 3a Quiescent state with ice formation in another embodiment;

4 . 4a and 4b show a further embodiment with allowable space expansion in all flow channels;

5 and 5a - Section of a heat exchanger with an inlet or outlet channel;

6 - View of a trough-shaped plate from the plate stack;

7 and 8th - Cutouts from a plate stack of other embodiments;

The 9 - 11 show views of plates of other embodiments.

The following description of the embodiments heat exchanger according to the invention, takes place using the example of a capacitor which is a part of an energy recovery system, not shown. However, the heat exchanger according to the invention is not limited thereto. It can be used in other systems or circuits and for any other purposes than heat exchangers and, if necessary, also be modified accordingly.

For example, it may also be a condenser (or evaporator) in an air conditioning system in which a refrigerant and, for example, the cooling liquid of an internal combustion engine are in heat exchange. Likewise, the use of the heat exchanger as oil cooler and also for other applications is possible.

Some of the accompanying drawings may only serve to explain the substance. For example, the show 2 to 4 not the actual distances in the disk plane 12 between the first and second formations 21 . 23 , therefore, by several arrows 12 in 1 indicated. In terms of 1 It should also be noted that a practical embodiment in both the plate longitudinal direction and in the plate transverse direction could have a plurality of approximately circular arrangements, which are described in more detail below. In 1 only three such arrangements have been shown in the longitudinal direction and two in the transverse direction.

The capacitor has a stack 1 from preferably trough-shaped plates 2 with a circumferential, bent edge 24 ( 5 . 6 ) on. The plate bottoms 20 have localized formations 21 in between the plate floors 20 arranged flow channels 3 . 4 protrude. The flow channels 3 . 4 are hydraulically with vertically through the plate stack 1 extending and out of alignment holes 22 in the plate floors 20 formed, inlet and outlet channels 5 . 6 . 7 . 8th connected for two media. The holes 22 that the inflow channel 5 form for the water vapor, have a larger cross-section than the other holes 22 or the channels formed thereby 6 . 7 . 8th in order to be able to absorb a sufficient volume of vapor flow, which is cooled and condensed during the flow, wherein its volume gradually decreases during the liquefaction. Through the outlet channel 8th the condensed steam as water leaves the condenser. For example, a liquid coolant flows through the inlet channel 7 and exits the condenser through the outlet channel 6 ,

There are first local forms 21 extending into the flow channels 3 for one of the media ( 2 into the coolant channels ( 3 )). Two opposite first local formations which form a pair P have one - with respect to the plate planes 20 - vertical distance 11 from each other. In the embodiment according to the 1 and 2 It can be seen that each pair P of the first local formations 21 from a local depression 21.1 in the one plate 2 and a local survey 21.2 is formed in the adjacent other plate.

It may also be several pairs P of such first local formations 21 act what is in 1 should be indicated by additional approximately centric points.

In an embodiment not shown, there are no pairs P of first local formations. However, there is also the vertical distance 11 before that of the first local formation 21 (survey 21.1 ) to an opposite, preferably flat so not deformed plate portion is sufficient.

Furthermore, there is a crowd (6 pieces in the embodiment according to 1 ) from second local formations 23 , around the first local formations 21 is arranged around. The term "crowd" is usually a variety to understand, so that in other embodiments, the number may be much larger but smaller than six. Also the second local formations 23 extend into the flow channels, namely, according to 2 , into the channels 4 for the work equipment. Preferably, the second local formations 23 also in pairs P2 of two diametrically arranged formations 23 arranged, however, in contrast to the pairs P first local formations 21 are firmly connected to each other. The connection takes place on roof-like sections of the formations 23 , such as the 2 . 3 or 4 demonstrate.

Each pair P2 also consists of a local depression 23.1 in the one plate 2 and from a local survey 23.2 in the neighboring other plate 2 which, as mentioned, are interconnected. As a suitable connection method is primarily a known from the prior art soldering process for the entire heat exchanger into consideration.

Again, it is possible to provide no pairs P2, but only in each case a second local formation 23 firmly connected to a diametral flat plate portion, which was also not shown in the drawings, because such configurations are not preferred. It is understood that the height of such formations 23 must correspond to the height of the flow channel.

The second local formations 23 have a defined distance in the plane of the plate 12 from the centric (center Z) arranged first local formations 21 and thus define an expandable space 10 , Together with the first local formations 21 and their vertical distances 11 from each other, they limit the spatial extent in the flow channels 4 for the other medium. The defined distance 12 and other parameters are set by the designer in order to realize the desired (allowable) space expansion.

How out 2a it can be seen that the spatial expansion in the center Z is greatest. In the periphery hardly a space expansion is possible, since the second local formations 23 - as mentioned several times - are diametrically firmly connected.

As will be further understood and understood, the expandable spaces are 10 around open spaces 10 in the flow channels 3 . 4 since these must be flowed through. Another term for this could be "spatially expandable zones 10" whose centers Z are preferably each by a pair P of first local formations 21 are shown.

If you look at the proposed construction as an architecture and embark on a virtual journey through the flow channels 3 The journey would pass through numerous contiguous, approximately circular pillared halls, with the columns passing through the interconnected second local formations 23 are shown and wherein - apart from the central first local formations 21 - level floor and ceiling parts of the "pillared hall" are present, through sections (zones 10 ) of two adjacent plates 2 are formed.

Especially with regard to the above-mentioned suitability of the heat exchanger for other purposes (oil cooler, intercooler, exhaust gas cooler or intercooler in cycle processes, etc.), it should be noted at this point that it may be possible and even preferred, in the preceding paragraph addressed flat floor - and ceiling sections of the pillared halls - ie in the flat plate sections - not shown in the drawings form further local formations as a turbulence generator. These turbulators are not connected diametrically. Preferably, they also have a vertical distance from each other. The space expansion can be even improved with appropriate design of the turbulence generator, because the strain or elasticity in the plates 2 can be relieved.

The maximum permissible space is about 9%. It should be in the elastic range, at least not lead to plastic deformation. In the presentation 2a only 7% were reported.

It is advantageous if the share, for example, approximately circular or slightly oval around at least one pair P of the first local formations 21 is arranged around. Depending on the size of the plates, several such circles K or ovals ( 1 ) from second local formations 23 provided, respectively, by at least one pair P of the first local formations 21 are arranged around.

To the number of second local formations 23 but also to a desired arrangement density of the local formations 21 . 23 It is of advantage to realize that the circles are tangent, partly even slightly overlapping, and that second local formations arranged in the tangents 23 belong both to the one and to another adjacent circle K. In the embodiment according to 1 Four of the six second local formations each belong to horizontally adjacent circles. Two of the local formations each belong to vertically adjacent circles.

Because the second local formations 23 in the embodiment shown are preferably arranged in circles K, has the mentioned defined distance 12 the second local formations 23 to the at least one central first local formation 21 around the same size. The first local formation 21 Thus, for example, the center of the circle Z represents the center of the circle. For this reason, the forces resulting from the expansion of the space, for example due to ice formation, become uniform over all pairs of second local formations 23 distributed. The risk of breaking individual solder joints due to overloading is reduced.

The height of the first local formations forming the pairs P. 21 is smaller than the height of the second local formations forming the pairs P2 23 what's out of the 2 to 4 is apparent. The lower height of the first formations 21 lets the vertical distance 11 between two first formations 21 to. The sum of the heights of two first local formations 21 is therefore smaller than the height of the flow channel, in which they extend.

Correlating with this is the height of the second local formations 23 Preferably, about half as large as the height of the flow channel, in which they extend.

As the 1 and others show are the formations 21 . 23 in this embodiment, approximately circular pimples.

According to the embodiment which in the 3 and 3a but also in 8th show some of the plates 2 local surveys 21.2 . 23.2 on and other of the plates 2 localized depressions 21.1 . 23.1 , where in the plate stack the plates 2 with the wells and the plates 2 alternate with the surveys.

How, however, the 2 and 2a . 4 . 4a and 4b , but also 7 show, all plates have 2 of the disk stack 1 localized depressions 21.1 . 23.1 and local surveys 21.2 . 23.2 the plate floors 20 on that through the first 21 and the second local formations 23 are formed.

As the 4 . 4a and 4b further, the pairs P comprise first local formations 21 at least one other pair P1, consisting of a survey in the same one plate 2 and a depression in the same other plate 2 is formed. With such a configuration, a spatial expansion in both flow channels 3 and 4 be shown what a comparison of the 4a and 4b is apparent. These plates 2 have a total of three types of formations 21 . 23 , First the second local formations 23 as one type and then two types of first local formations 21 represented by the pairs P and P1, the pairs P1 being multiple. The pairs P are also in the embodiments according to the 2 and 3 available.

The 5 and 5a show in a section of the heat exchanger a suitable development, which consists in that the inlet and / or outlet channels 5 . 6 . 7 . 8th allow the heat exchanger a certain elastic expansion with ice formation. This is achieved by the fact that the top plate 15 of trough-shaped plates 2 formed plate stack 1 immediately under a slightly thicker cover plate 13 is arranged without the holes mentioned above 22 - So closed - is formed. This intermediate plate 15 must be at the hole edges of the next plate 2 also not be soldered. As a result, she will, as in 5a can be seen in ice formation, which is known to be accompanied by enormous pressure increase, bulge upwards (bulge 16 ), so can expand and thus a certain increase in space of the inlet and outlet channels 4 . 5 . 6 . 7 allow. Corresponding to it has the cover plate 13 an outward curvature that limits the spatial extent and thus prevents destruction in a certain way. In the curvature of the cover plate 13 can, as shown, an opening 14 find the bulge 16 the intermediate plate 15 to facilitate.

Another in the 5 merely indicated possibility to achieve a certain elasticity, is in the inlet and / or outlet channels, additionally or alternatively, a flexible, elastic or a compressible element 9 introduce or arrange in the channel, which compensates for the volume expansion. This can be arbitrary in shape. Suitable, for example, is a flat tubular element which can deform inwardly or any other shapes or other materials which may be suitable.

The 6 shows, in contrast to 1 , a trough-shaped plate 2 with eight circularly arranged second formations 23 , the wells here 23.2 are. In the plate below, not shown 2 there are corresponding surveys 23.1 that with the wells 23.2 are connected. In the middle of the circles K is a first shape 21 , In the 6 these are the first forms 21 around surveys 21.1 from the plate 2 , The top plate following 2 then has a corresponding first shape as a recess 21.2 , In between lies the vertical distance 11 ,

In spite of the desired elasticity with this proposal, the necessary stability in all flow channels 3 . 4 To obtain and to ensure good manufacturability in a soldering process, can be used in plate areas outside the expandable spaces 10 lie, further isolated formations 24 to be ordered. Also these other forms 24 are preferably designed as diametrically connected pairs. In the 6 and 10 are some of these further forms 24 been hinted at. The further formations 24 are opposite to the second formations 23 aligned, that is, they protrude into those flow channels 4 into it and stabilize it. There they also cause turbulence. The second formations 23 protrude into the other flow channels 3 into it.

However, it is also possible to have adjacent second formations 23 alternately as elevations and depressions to design. This means that with respect to the embodiment described in the preceding paragraph, at least some - not all - of the second formations 23 into the other flow channels 3 protrude and of course with diametral formations 23 the adjacent plate are connected.

The 7 and 8th show part - longitudinal sections through plate stacks 1 other embodiments. They are spaced first formations 21 and connected second formations 23 seen. In 7 own all plates 2 of the disk stack 1 Elevations and depressions. In 8th alternate plates 2 with elevations with other plates 2 from, which have only depressions.

The 9 . 10 and 11 show embodiments with four second local formations 23 around central first formations 21 are arranged around. The four local formations 23 are each arranged in the corners of approximately square patterns. In 10 are the squares, opposite to the representation in 9 been arranged rotated by 90 °. In 11 there is only one central shape each 21 , in the 9 and 10 however two each. The number of central first formations 21 and the arrangement of the flocks of second local formations 23 can, as one should see, be combined in many ways within the scope of the invention.

LIST OF REFERENCE NUMBERS

1

plate stack

2

plates

3

flow channels

4

other flow channels

5-8

Inlet and outlet channels

9

compressible element (rubber, airbag, etc.)

10

expandable spaces (zones)

11

vertical distance between two (one pair) formations 21

12

defined distance between formations 21 and 23

13

cover plate

14

opening

15

intermediate plate

16

bulge

20

trays

21

first local formations

21.1

surveys

21.2

wells

22

holes

23

second local formations

23.1

surveys

23.2

wells

24

further formations

25

plate edges

K

circles

P

pairs

P1

other couples

P2

more couples

Z

center

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1612499 A2 [0002, 0023]
• JP 2001-099588 A [0003]
• DE 3227206 C2 [0006]

Claims (23)

Heat exchanger, a stack ( 1 ) from plates ( 2 ), with localized formations ( 21 ) in the plates ( 2 ), in between the plates ( 2 ) arranged flow channels ( 3 . 4 ), which hydraulically with through the plate stack ( 1 ) extending and aligned holes ( 22 ) in the plates ( 2 ) formed inlet and outlet channels ( 5 . 6 . 7 . 8th ) for two media, characterized in that first of the local formations ( 21 ) into the flow channels ( 3 . 4 ) for which one of the media extends into - in relation to the plate levels ( 20 ) - vertical distance ( 11 ), either from each other or to an opposite plate portion of the adjacent plate (FIG. 2 ) and that a family of second local formations ( 23 ) with a defined distance ( 12 ) - seen in plate plane - around the first local formations ( 21 ) arranged either diametrally with each other or with a diametral plate portion of the adjacent plate (FIG. 2 ) are connected. Heat exchanger according to claim 1, characterized in that in each case around the first local formations ( 21 ) around to the second local formations ( 23 ) extendable space ( 10 ) is provided. Heat exchanger according to claim 1 and 2, characterized in that an allowable spatial extent is about 9%. Heat exchanger according to one of the preceding claims, characterized in that the first local formations ( 21 ) are preferably arranged in pairs (P) and each pair from a local depression ( 21.2 ) in one plate and a diametrical local survey ( 21.1 ) is formed in the adjacent other plate, wherein the first local formations may be arranged in a plurality of pairs (P). Heat exchanger according to one of the preceding claims, in particular according to claim 4, characterized in that the pairs (P) of first local formations comprise at least one further pair formed by a projection in one plate and a recess in the other plate. Heat exchanger according to one of the preceding claims, characterized in that the defined distance ( 12 ) of the second local formations ( 23 ) to the first local formations ( 21 ) the size of the expandable rooms ( 10 ) in the flow channels ( 4 ) for the other medium. Heat exchanger according to claim 6, characterized in that the localized second formations ( 23 ) are preferably arranged in pairs (P2) and each pair (P2) from a local depression (P2) 23.2 ) in one plate and from a local survey ( 23.1 ) in the adjacent other plate. Heat exchanger according to claims 6 and 7, characterized in that the family of pairs (P2), for example as a circle (K) or oval around at least one pair (P) of the first local formations (P2) 21 ) is arranged around. Heat exchanger according to claims 6, 7 and 8, characterized in that a plurality of, for example, circles (K) of second local formations are provided which each extend around at least one of the first local formations. Heat exchanger according to claims 6 to 9, characterized in that the, for example, circles (K) are tangent and arranged in the tangents second local formations belong to both the one and the other adjacent, for example, circle. Heat exchanger according to one of the preceding claims, characterized in that the defined distance ( 12 ) of the second local formations ( 23 ) around at least one of the first local formations ( 21 ) around the same size. Heat exchanger according to one of the preceding claims, characterized in that the height of the first local formations ( 21 ) is smaller than the height of the second local formations ( 23 ). Heat exchanger according to claim 1, characterized in that the sum of the heights of the first local formations ( 21 ) is smaller than the height of the flow channel in which they extend. Heat exchanger according to claim 1, characterized in that the height of the second local formations ( 23 ) is about half the height of the flow channel in which they extend. Heat exchanger according to one of the preceding claims, characterized in that the first and second local formations ( 21 . 23 ) are preferably approximately circular knobs. Heat exchanger according to one of the preceding claims, characterized in that all plates ( 2 ) of the disk stack ( 1 ) have localized pits and localized surveys 21 ) and the second local formations ( 23 ) are formed. Heat exchanger according to claim 1, characterized in that some of the plates have localized elevations and others of the plates have localized depressions, the plates in the plate stack alternating with the depressions with the plates having the elevations. Heat exchanger according to one of the preceding claims, characterized in that the plates ( 2 ) are trough-shaped and stackable with each other, wherein they at the tub-shaped edge ( 25 ) abut each other. Heat exchanger according to one of the preceding claims, characterized in that in plate areas which do not belong to the expandable spaces ( 10 ) include further diametrically connected formations ( 24 ) are arranged. Heat exchanger according to one of the preceding claims, characterized in that the trough-shaped plates ( 2 ) a plate floor ( 20 ), the local formations ( 21 . 23 . 24 ) in the plate floors ( 20 ) are formed. Heat exchanger according to one of the preceding claims, characterized in that the plate stack ( 1 ) between a cover plate ( 13 ) and a heat exchanger plate ( 2 ) an intermediate plate ( 15 ), which without the holes ( 22 ) is formed so that at a pressure increase in the associated inlet and / or outflow ( 5 . 6 . 7 . 8th ) can take place an enlargement, whereby the intermediate plate ( 15 ) bulges in the elastic region. Heat exchanger according to one of the preceding claims, characterized in that an elastic element ( 9 ) in the inlet and / or outlet channels ( 5 - 8th ) can be arranged. Heat exchanger according to one or more of the preceding claims, characterized in that the heat exchanger as a capacitor in an energy recovery system, for example in a motor vehicle, is usable.

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