EP0321480B1 - Plate-type heat exchanger - Google Patents

Abstract

Plate-type heat exchanger, having at least three superimposed heat exchange plates (1, 2), whereby each pair of successive plates (1, 2) forms a through-passage (3, 4). The heat exchange plates (1, 2) consist of sheet metal and, in order to form through-ducts between the plates (1, 2) and to provide mutual support between the latter, are provided with a pressed-in wave pattern which covers the through-passage (3, 4), said pattern forming grooves (9, 10) which run transversely to the wave direction (11) and obliquely to the through-passage centre-line (7). The surface of the wave pattern (5) of each exchange plate consists of a number of mutually-adjacent partial regions (5a, 5c) whereby the grooves (9, 10) form in the individual partial areas (5a, 5c) groove sections (12) running parallel to one another in each group, said sections ending at the limits (14) of said partial area; the groups of the groove sections (12) of different partial areas (5a, 5c) run transversely to one another. Directly facing each partial area (5a, 5c) of the wave pattern (5) of one heat exchange plate (1, 2) is an equally-sized partial area (5a, 5c) of the wave pattern (5) of another heat exchange plate (1, 2) which forms with the first-mentioned plate (1, 2) a through-passage (3, 4). In at least one pair of exchange plates (1, 2) forming mutually a through-passage (3, 4) the wave vertices (17) of one plate (1, 2) are supported, only in the region of the ends (21) of the groove sections (12) of this plate (1, 2), on the wave vertices (18) of the other plate (1, 2) of the pair, and similarly in the region of the ends of the groove sections (12) of said other plate (1, 2), and freely pass over the distance between these support points (20). In particular, the wave vertices (17) of one plate (1, 2) of a pair of plates (1, 2) forming with one another a through-passage (3, 4) are supported by one of their ends on the end of one of the wave vertices (18), facing this plate, of the other plate (1, 2) and by their other end on the end of one of the parallel wave vertices (18), adjacent to the last wave vertex (18), of the other plate (1, 2) and freely pass over the intervening depression in the wave pattern (5) of the other plate (1, 2).

Description

The invention relates to a plate heat exchanger which has at least three stacked exchanger plates, two successive exchanger plates each forming a flow path, which exchanger plates are made of sheet metal and to form flow channels between the plates and to support the plates with a pressed-in flow path overlapping wave pattern are provided, which forms transverse to the wave direction and obliquely to the flow center line, the surface of the wave pattern of each exchanger plate consists of a number of adjoining partial areas, the grooves in the individual partial areas each forming a family of mutually parallel groove sections which on the Limits of the relevant area end, and the coulters of the groove sections of different partial areas run obliquely to each other and each partial area of the wave pattern of an exchange cherplatte a same-sized portion of the wave pattern of another exchanger plate, which forms a flow path with the first-mentioned plate, opposite one another.

Plate heat exchangers enable the transfer of large amounts of heat from one medium to another medium with a comparatively small space requirement and are used and find, in addition to pure heat transport tasks, for heating or cooling substances before or after a chemical or physical treatment of them or before or after storing them frequently used in the execution of chemical and / or physical treatments or chemical reactions of flowable substances. Maintaining a certain temperature profile of the media passing through the plate heat exchanger in the course of the flow is often of great importance. Also of great importance is the possibility of being able to easily select or design the flow resistance in the flow channels in accordance with the respective application for each of the media flowing through such a plate heat exchanger. The quantities and the physical properties of the individual media, between which heat transfer is to take place in the plate heat exchanger, often deviate from one another, and a different design of the flow channels for the different media which are passed through a plate heat exchanger should therefore be provided. In addition to such requirements with regard to the flow properties of the flow channels of the plate heat exchangers, there is also the requirement for effective support of the exchanger plates against one another in the area of the flow channels, so that the intended geometry of the flow channels also under the influence of the pressures under which the media passing through such a plate heat exchanger are located. is maintained as unchanged as possible. Mutual support of two adjacent exchanger plates, which together form a flow channel, is obtained in a simple manner if the groove sections of the wave pattern of one exchanger plate cover the groove sections of the wave pattern of the other exchanger plate in such a way that the two superimposed sets of groove sections form a grid-like pattern with one another ; the flow resistance that results in the flow channel with such an arrangement of two exchanger plates is relatively high.

In order to reduce the flow resistance at the inflow-side and at the outflow-side end of flow channels designed in this way, it has already been proposed to form the groove sections of the wave pattern lying in the area of these ends, each with a plate of each plate pair, with these groove sections being a section running parallel to the flow direction and then one have a section inclined to the flow direction (GB-A-1 288 887).

In order to achieve a lower flow resistance, it is also known to provide the groove sections of one plate of a pair of exchanger plates, which form a flow channel with one another, parallel to the groove sections of the other exchanger plates of this pair and to form ribs in the plates for mutual support of the two plates, which run approximately in the direction of flow (FR-PS 2 341 119); the molding of such ribs complicates the production of the wave pattern of the exchanger plates and often also impairs the flow properties in the flow channels formed with such exchanger plates; such ribs serving to support the plates increase the flow resistance in the flow path between plates with groove sections running parallel to one another and thereby impair the uniform flow of the flow, and there is an even greater change in the flow properties if one adjoins these flow channels Flow channels with a higher flow resistance are provided by using the above-mentioned crossed position of the groove sections of two exchanger plates forming a flow channel with one another, since the formations of the exchanger plates, which form the ribs which serve to support mutually parallel groove sections, create grooves on their rear side, and such Grooves in a crossed wave pattern can strongly disrupt the flow behavior. Moreover, the above-mentioned molding of support ribs, which serve to mutually support adjacent exchanger plates, complicates the manufacture of such exchanger plates considerably. A form that complicates the manufacture considerably the exchanger plates are also present in a heat exchanger described in FR-PS 2 559 575; in this the shaft crests of the exchanger plates are designed in a rack-like manner, with mutually opposite shaft crests distributed over their entire length, touching at a plurality of locations on each shaft crest.

It is the object of the present invention to provide a plate heat exchanger of the type mentioned at the outset, in which a good mutual support of adjacent exchanger plates can be obtained in the region of flow channels with low flow resistance in a simple manner, while at the same time a good swirl in these flow channels despite the low flow resistance of the flowing medium, which favors the heat transfer, should be achievable and should not adversely affect the flow behavior through the measures provided for the mutual support of the exchanger plates.

The plate heat exchanger according to the invention of the type mentioned at the outset is characterized in that, in the case of at least one pair of exchanger plates which form a flow path with one another, the wave crests of the one plate are located only in the region of the ends of the groove sections of this plate on the opposite wave crests of the other plate of the pair, and likewise support in the area of the ends of the groove sections of said other plate and freely span the distance between these support points. By the aforementioned design of the plate heat exchanger, the aforementioned objective can be met well. By supporting the exchanger plates against one another only in the region of the ends of the groove sections, an adverse influence on the flow properties in the flow channels can be largely prevented by the mutual support of the exchanger plates, and there is the intended mutual support of adjacent exchanger plates at the apices of the wave pattern of these plates Possibility of very simple production. The mutual support that only takes place at the wave apexes of the wave pattern also avoids impairments of the flow conditions in other flow channels, which are limited by the back of the exchanger plates, and it results from the fact that the support is provided without webs, knobs or the like that are additionally molded into the plates . also simplifies production.

A preferred embodiment of the plate heat exchanger according to the invention is characterized in that the wave apexes running along the groove sections of the partial regions of the wave pattern of the one exchanger plate of a pair of plates forming a flow path, which wave apexes face the other plate of this pair of plates, have one end at the end of one of the plate pairs support a plate facing the wave crest of the other plate and with its other end at the end of a parallel wave crest of the other plate adjacent to the latter wave crest and freely spanning the valley groove in between of the wave pattern of the other plate. This training has the advantage of a particularly favorable flow behavior. An advantageous variant is characterized in that the wave pattern of the exchanger plates is formed by more than two sections abutting one another at separating lines, the groove sections forming groove trains adjoining one another via the separating lines, and in the course of such groove trains between a support point located in a groove section and one in another support section located one or more groove sections, in which the groove trains of the two plates of a pair of exchanger plates follow one another and run without mutual support. This training results in a further improvement in the flow behavior and is particularly suitable in those cases in which work is carried out at relatively low pressures, so that the mutual support of the exchanger plates forming a flow channel with one another can be provided at greater intervals.

A second preferred embodiment of the aforementioned embodiment of the plate heat exchanger according to the invention is characterized in that the wave pattern of the exchanger plates has an even number of partial areas which follow one another in the direction of flow or transversely thereto, with the groove sections at a first angle to one half of the number of partial areas Flow direction, and in the other half of the number of sub-areas, the groove sections run at a second angle to the flow direction, the longitudinal extent of the individual sub-areas measured in the direction of the sequence of the sub-areas being the same, and when such an exchange plate is placed one on top of the other, the same trained heat exchanger plate, which is rotated by 180 ° about an axis perpendicular to the geometric center of the plate, the partial areas at a first angle to the flow direction ng extending groove sections of one plate opposite the part areas with groove sections running at a second angle to the flow direction of the other plate and here the wave apex of the wave pattern of the second pattern plate facing the first-mentioned plate in the individual partial areas of the wave pattern on the wave apex of the wave pattern of the second-mentioned plate first mentioned plate only come to rest at the ends of the groove sections of the individual partial areas. This embodiment has the advantage of the proposed division of the wave pattern that the in the individual sub-areas compensate for differences in thermal behavior (thermal length) well in their sum and thus overall a balanced thermal behavior is achieved, and the further advantage that in this configuration of the wave pattern such a simple plate from two Exchanger plate pair can be formed, wherein one plate of this pair is pivoted with respect to the other plate by 180 ° about a geometric axis running through the geometric center of the plates perpendicular to the plane of the plate.

The two angles mentioned, which enclose the mutually supporting groove sections with the flow direction, differ less than 30 °. It is further advantageous for achieving such a construction of a pair formed from two identical exchanger plates and also for the mutual compensation of the thermal properties of the partial areas of the wave pattern, if it is provided that the wave pattern of the exchanger plates has a number of partial areas which can be divided by four, which lie in two surface strips which are separated by a dividing line running in the direction of flow or transversely thereto, the wave pattern being mirror-inverted with respect to the dividing line between the two surface strips.

Another embodiment of a plate heat exchanger of the abovementioned design which is advantageous with regard to the flow properties is characterized in that the wave pattern of the exchanger plates is formed by four or more partial areas, viewed in the flow direction, lying adjacent to one another in pairs and abutting on separation lines, the groove sections forming groove trains adjoining one another via the separation lines , which run from one longitudinal edge of the wave pattern to the other longitudinal edge of the wave pattern and wherein in the groove trains the groove sections follow one another in zigzag fashion and in each case a pair of groove sections which run more obliquely to the flow direction follows and follows each other on a pair of groove sections which run more obliquely to the flow direction the tips of the more oblique groove portions of one plate of a pair of exchanger plates on the tips of the less oblique leaves supported on the groove portions of the other plate of this pair and conversely the tips of the more inclined groove portions of the other plate of a pair are supported on the tips of the less inclined groove portions of the one plate of the pair.

A further embodiment of the above-mentioned design of a plate heat exchanger according to the invention, which allows a particularly low flow resistance to be achieved, is characterized in that the wave pattern of the exchanger plates is formed by four or more partial areas, viewed in the flow direction, lying side by side, butting against one another on parting lines, the groove sections over the dividing lines next to one another form grooves which run from one longitudinal edge of the wave pattern to the other longitudinal edge of the wave pattern, and wherein the groove sections in the groove sections follow one another in a zigzag fashion and at least one pair of groove sections which run more obliquely to the flow direction is provided on the several pairs of less oblique groove sections follow and the tips of the more oblique groove sections of one plate e Support a pair of exchanger plates on tips of the less inclined groove portions of the other plate of the pair and the tips of the more inclined groove portions of the other plate of the pair on the tips of less inclined groove portions of the one plate of the pair, and that between the support points in the train of a groove train are several groove sections, which follow parallel to this groove sections of the other plate of the exchanger plate pair and in which there is no mutual support of the two plates of the exchanger plate pair.

A very simple embodiment in terms of manufacture is obtained if it is provided that the wave pattern of the exchanger plates is formed by two partial regions lying adjacent to one another in the flow direction and abutting on a dividing line, the geometrical extension of the groove sections of the one partial region being at the dividing line with a covers the beginning of the groove section of the other partial area and leaves this groove section at an angle at the outer edge of the other partial area parallel to the dividing line with a groove section adjacent to this grooved section and also the geometrical extension of the groove sections of the other partial area at the dividing line with a groove section starting there of a partial area and leaving this groove section obliquely on the outer edge parallel to the dividing line of the one partial area with a groove section to this Cut adjacent groove section comes to cover, and that the two plates of a pair of exchanger plates support each other at these cover points.

Another embodiment of the plate heat exchanger according to the invention is characterized in that in the case of both exchanger plates forming a flow path with one another, the groove sections are parts of zigzag-shaped groove trains, the zigzag groove sections preferably running approximately perpendicular to one another such that the groove sections of the groove trains are two different ones Have lengths that differ by the width of one or two grooves, and that the groove portions of one plate of the exchanger plate a pair of each overlap in alignment with a groove section of the other plate, a shorter groove section of one plate overlapping with a longer groove section of the other plate and a shorter groove section of the other plate overlapping with a longer groove section of one plate.

If you want to provide flow paths with different flow properties in the heat exchanger, it is advantageous if two different types of exchanger plates are provided in the heat exchanger and here two exchanger plates of the same type lie one on top of the other to form a flow path for the one medium and the different pairs of exchanger plates alternately one after the other, and a flow path for the other medium is formed between the mutually differently arranged adjacent exchange plates of successive pairs of exchange plates, the groove sections of the wave patterns of the one plate of two adjacent differently formed exchange plates crossing over several groove sections of the other of these two exchange plates with the crest of the groove portions of one plate on the opposite crest of the other Plate abut at a plurality of contact points, which are distributed over the longitudinal extent of the groove sections. An embodiment is particularly favorable in terms of production technology, which is characterized in that the wave pattern of one type of exchanger plate is geometrically related to the wave pattern of the other type of exchanger plate, the one pattern being different from the other by pivoting through 180 ° in the plane of the pattern lying and preferably passing through the center of the geometric axis and / or by interchanging partial areas of the pattern with each other. It is furthermore advantageous in the interest of a uniform flow if the intersections of the groove sections of the wave patterns of two plates lying next to one another and forming a flow path lie symmetrically with respect to a center line of the plates lying approximately in the plane of the plate.

It is advantageous for the configuration of the flow paths in the plate heat exchanger if it is provided that the pairs of exchanger plates which are identical to one another have the same position or orientation in the exchanger.

• Fig. 1 einen Teil eines Plattenwärmeaustauschers mit mehreren miteinander einen Durchflußweg bildenden Plattenpaaren im Längsschnitt,
• Fig. 2 eine bei einem solchen Plattenwarmeaustauscher vorgesehene Austauscherplatte in Draufsicht,
• Fig. 3 gleichfalls in Draufsicht einen Teil des Wellenmusters eines Austauscherplattenpaares eines erfindungsgemäßen Wärmeaustauschers in Draufsicht,
• Fig. 4 dieses Plattenpaar im Schnitt gemäß der Linie IV-IV in Fig. 3,
• Fig. 5 einen Schnitt gemäß der Linie V-V in Fig. 3;
  • die Fig. 6a bis 13a zeigen in einer der Fig. 3 entsprechenden Darstellung Ausschnitte des Wellenmusters von Austauscherplattenpaaren erfindungsgemäß ausgebildeter Plattenwärmeaustauscher;
  • die Fig. 6b bis 13b hiezu korrespondierend je eine Platte eines solchen Austauscherplattenpaares,
  • die Fig. 6c bis 13c je eine durch Wendung oder Versetzung des Wellenmusters aus den Platten nach Fig. 6b bis 13b hergeleitete modifizierte Platte,
  • die Fig. 6d bis 13d Austauscherplattenpaare, die je aus einer Platte nach den Fig. 6b bis 13b und einer Platte nach den Fig. 6c bis 13c gebildet sind und einen höheren Durchflußwiderstand der Durchflußwege haben als die in den Fig. 6a bis 13a dargestellten Austauscherplattenpaare.

The invention will now be further explained with reference to examples which are shown schematically in the drawing. In the drawing shows

• 1 shows a part of a plate heat exchanger with several plate pairs forming a flow path with one another in longitudinal section,
• 2 is a top view of an exchanger plate provided in such a plate heat exchanger,
• 3 is also a top view of part of the wave pattern of a pair of exchanger plates of a heat exchanger according to the invention in a top view,
• 4 this pair of plates in section along the line IV-IV in Fig. 3,
• 5 shows a section along the line VV in Fig. 3.
  • 6a to 13a show in a representation corresponding to FIG. 3 sections of the wave pattern of exchanger plate pairs of plate heat exchangers designed according to the invention;
  • 6b to 13b corresponding to each one plate of such a pair of exchanger plates,
  • 6c to 13c each a modified plate derived from the plates according to FIGS. 6b to 13b by turning or displacing the wave pattern,
  • 6d to 13d exchanger plate pairs, which are each formed from a plate according to FIGS. 6b to 13b and a plate according to FIGS. 6c to 13c and have a higher flow resistance of the flow paths than the exchanger plate pairs shown in FIGS. 6a to 13a .

Plate heat exchangers, as is shown schematically in FIGS. 1 and 2, have a number of packet-like stacked exchanger plates, with two successive exchanger plates 1 in the packet layering, a flow path 3 or 4 for one of the media to be passed through the heat exchanger between where the heat exchange takes place. Usually two media are passed through the heat exchanger and flow paths 3 are provided in alternating order for one medium and flow paths 4 for the other medium. These flow paths 3, 4 each lie between successive exchanger plates, wherein in the case shown in FIG. 1 a pair of exchanger plates of the same type, that is a plate pair 1, 1 or 2, 2, form the flow paths 3 for the one medium, and Form plate pairs from exchanger plates of different types, ie plate pairs 1, 2 or 2, 1, flow paths 4 for the other medium. In order to give the flow paths the desired thermal and flow properties, or the desired 'thermal length', the exchanger plates 1, 2 are provided with a wave pattern 5, the surface of the wave pattern 5 of each exchanger plate 1, 2 consisting of a number of adjoining partial areas 5a, 5b, 5c, 5d. The flow of the media, which are passed through the heat exchanger, runs from one of the connection openings 6 of such a heat exchanger plate to another connection opening 6 thereof, the flow path 3, 4 in question being covered by the wave pattern 5 and in the area of the wave pattern essentially the flow center line 7 follows or as the arrows 8 indicate, runs parallel to this. The wave pattern forms grooves 9, 10 which are transverse to the wave direction 11 and oblique to the flow line 7 run. The grooves 9, 10 form in the individual sections 5a, 5b, 5c, 5d of the wave pattern 5 a group of groove sections 12 which run parallel to one another and which end at the boundaries 14 of the relevant section. The groups of the groove sections 12 of different partial areas run obliquely to one another. Each sub-area of the wave pattern of one exchanger plate is flush with an equally large sub-area of the wave pattern of another exchanger plate, which forms a flow path 3, 4 with the first-mentioned plate. The wave patterns of the two exchanger plates forming a flow path lie against one another at individual points, so that these plates are supported against one another, which with regard to pressure differences which are present in the individual flow paths 3, 4 and cause forces which act on the plates in the transverse direction 15 , is important.

At individual points in the wave pattern, the wave crests 17 of one plate of a pair of exchanger plates forming a flow path are supported on the opposite wave crests 18 of the other plate of the pair. The support points 20, as shown in FIG. 3, in which a part of such a pair of plates is shown in plan view, are only in the area of the ends 21 of the groove sections 12. Thus, the lower wave crests 17 drawn in full lines in FIG. 3 lie at the top Exchanger plate at the mentioned support points 20 on the upper wave crests 18 shown in broken lines in FIG. 3 of the exchanger plate underneath, and the wave crests 17, 18 span the distance between the support points 20, resulting in flow paths between the plates which result in a favorable flow - And have heat transfer properties with low flow resistance. The valley groove of the wave pattern of one plate lying between the support points 20 is thus freely spanned by the wave apex of the other plate.

6a shows, in a representation analogous to FIG. 3, an embodiment in which two exchanger plates are arranged one above the other, the lower wave apex 17 of the wave pattern of the upper exchanger plate in full lines and the (upper) wave apex 18 of the wave pattern of the lower one facing this plate Exchanger plate are shown in dashed lines. In the interest of a clear representation, the overhead crest of the top plate and the crest of the bottom plate of the bottom plate of the pair of exchanger plates are not shown in FIG. 6a. A single plate 1 of this type is shown in FIG. 6b, analogously to the illustration in FIG. 6a, the lower wave apex 17 of the wave pattern is drawn with solid lines and the upper wave apex 17a of the wave pattern is drawn with dashed lines. To form the pair of exchanger plates shown in FIG. 6a, two plates according to FIG. 6b are placed one on top of the other, the bottom plate being rotated with respect to the top plate of the pair by 180 ° about a geometric axis perpendicular to the geometric center 30 of the plate (s) .

The wave pattern 5 of the plates has an even number, namely four, subregions 5a, 5b, 5c, 5d. These partial areas follow one another in the illustrated case in direction 7 of the flow center line. However, this wave pattern can also be provided offset by 90 ° with respect to the illustration in FIG. 6a, in which case the subregions then follow one another transversely to the flow direction. In two sections 5a, 5b of the wave pattern 5, the groove sections 12 run at a first angle a to the flow direction 7 and in the other two sections 5c, 5d of the wave pattern, the groove sections 12 run at a second angle β to the flow direction. The longitudinal extent 29 measured in the direction of the sequence of the partial areas is practically the same for all partial areas. As mentioned above, the position of the lower plate of the pair of plates shown in FIG. 6a rotated by 180 ° with respect to the upper plate thereof means that partial areas 5a, 5b of the upper plate, in which the groove sections 12 run at an angle a to the direction 7, Subareas 5c, 5d of the lower plate, in which the groove sections 12 run at an angle β to the direction 7, opposite, and subareas 5c, 5d of the upper plate lie opposite areas 5a, 5b of the lower plate. The wave crests 18 of the lower plate come with the wave crests 17 of the upper plate only at the ends 21 of the groove sections 12 located in the partial areas for mutual support, and the wave crests 17, 18 span the valleys lying between the support points of the crests opposite the relevant crest Plate free.

The plate shown in FIG. 6c is a modification of the plate according to FIG. 6b, and the wave pattern 5 'of the plate 2 according to FIG. 6c is obtained by turning the wave pattern 5 of the plate 1 according to FIG. 6b by one following the direction 7 , through the plate center 30 extending geometric axis through 180 °. The wave pattern 5 'according to FIG. 6c can thus be pressed into flat plate material with the same tool as the wave pattern 5 according to FIG. 6b; 6c, two plates 2 according to FIG. 6c can be put together to form a pair of plates, as described above for two plates 1 according to FIG. 6b, which forms a flow path with the same properties as the plate pair shown in FIG. 6a.

By assembling a plate according to FIG. 6b with a plate according to FIG. 6c, a plate pair according to FIG. 6d is obtained; in this pair of plates, the individual groove sections of the wave pattern of both plates each cross over a plurality of groove sections of the opposite plate, the shaft apex 17 of the upper one Successively rest the plate on a series of wave crests 18 of the lower plate; analogous to FIG. 6a, the wave crests 17 of the upper plate facing the lower plate are drawn with full lines in FIG. 6d and the wave crests 18 of the lower plate facing the upper plate are drawn with dashed lines; in the case shown in FIG. 6d, the upper plate of the plate pair is a plate according to FIG. 6b and the lower plate is a plate according to FIG. 6c. The intersecting course of the groove sections and the mutual contact of the shaft crests 17, 18 of the plates of the plate pair shown in FIG. 6d at a plurality of crossing points or support points results in a substantially higher flow resistance than is present in the plate pair according to FIG. 6a. The crossing points are distributed over the longitudinal extent of the groove sections. In this way, flow paths with different flow resistance or different thermal lengths can be provided in a simple manner in a heat exchanger and thus an adaptation to different properties of the media between which the heat exchange is to take place can be achieved. If plate pairs consisting of two plates 1 according to FIG. 6b and plate pairs consisting of two plates 2 according to FIG. 6c are arranged alternately in succession, one obtains a structure according to FIG. 1 in which flow paths 3 with low flow resistance, which are located between mutually identical plates according to FIG 6b or 6c are present, alternating with flow paths 4 with high flow resistance which are present between different plates according to FIGS. 6b and 6c. The flow paths 3 can be assigned to one and the flow paths 4 to the other of the two media flowing through the heat exchanger. However, it is also possible to construct the heat exchanger with plates which are identical to one another, the plates which are designed according to FIG. 6b or according to FIG. 6c being installed alternately offset by 180 ° and forming only plate pairs with one another according to FIG. 6a. All flow paths of the heat exchanger then have the same flow behavior or the same thermal length. This sequence of plates of the same design, with every second plate being offset by 180 °, results in an exchanger plate package in which the pairs of exchanger plates which are identical to one another, i.e. the plate pairs formed by the sequence of a plate in normal position and a plate in a position 180 ° apart, are formed on the one hand and, on the other hand, the plate pairs formed by the succession of a plate which is offset by 180 ° and a plate which is in the normal position have the same position or orientation in the exchanger. Such a mutually identical position or orientation of the flow paths 3 for the plate pairs forming one medium on the one hand and the plate pairs forming the flow paths 4 for the other medium also exists in the construction of an exchanger plate package described above, in which a plate according to FIG. 6b in the normal position is followed by a plate according to FIG. 6b in a position offset by 180 °, followed by a plate according to FIG. 6c in the normal position and this is followed by a plate according to FIG. 6c in a position offset by 180 °, and this sequence is repeated as often as desired .

The wave pattern 5, 5 'provided in the plates according to FIGS. 6b and 6c can, if desired, be provided several times in succession both in direction 7 of the flow center line and transversely thereto in order to achieve a larger wave pattern area on the exchanger plates.

The crossings or support points 20 'present in the exchanger plate pairs according to FIG. 6d of the groove sections of the wave pattern of the upper plate with the groove sections of the wave pattern of the lower plate lie approximately symmetrically with the dash-dotted center line, which lies approximately in the plate plane. As a result, a very uniform course of the flow properties over the surface extension of the wave pattern is obtained.

In the embodiment shown in FIGS. 7a and 7b, which is similar to the embodiment according to FIGS. 6a and 6b, the wave pattern of the exchanger plates is mirror-inverted with respect to a central dividing line 25. The wave pattern, which can be seen more clearly from FIG. 7b, which shows a plate of this embodiment, has a number that can be divided by four, eight in the illustrated case, partial areas 5a ', 5b', 5c ', 5d', 5a ", 5b" , 5c ", 5d", which lie successively in two surface strips 26, 27 running on both sides of the dividing line 25. In Fig. 7a and also in Figs. 8a to 13a, analogously to Fig. 6a, the lower crests 17 of the upper plate are drawn with full lines and the upper crests 18 of the lower plate with dashed lines and in Fig. 7b and further 8b to 13b, corresponding to FIG. 6b, the top crests of the plate in question are dashed and the bottom crests of the plate in question are drawn with solid lines.

In the embodiment according to FIG. 7a, of which, as mentioned, a single plate is shown in FIG. 7b, the groove sections 12 extend in the partial areas 5a ', 5c' and 5a ", 5c" at a first angle a to the flow direction 7 and in In the partial areas 5b ', 5d' and 5b ", 5d", the groove sections 12 extend at a second angle β to the flow direction 7. The longitudinal extent 29 of the partial areas, seen in the direction of the sequence of these areas in the surface strips 26, 27, is in all partial areas practically the same. Analogous to what was mentioned in connection with FIG. 6a, the wave pattern can also be provided offset by 90 ° with respect to the illustration in FIG. 7a in this case, so that the partial regions then follow one another transversely to the flow direction. Likewise, in the embodiment according to FIG. 7a and also in further embodiments to be described below, it is possible, in order to achieve a larger wave pattern area on the exchanger plates, to provide the wave patterns shown in the drawing in the direction 7 of the flow center line and / or transversely thereto several times in succession.

Analogous to the plate pair according to FIG. 6a, the lower plate with respect to the upper plate is also perpendicular to the plate plate according to FIG. 7a and the plate pairs shown in FIGS. 8a to 13a to be described geometric axis, which runs through the plate center 30, rotated by 180 °. 7a, partial areas 5a ', 5c', 5a ", 5c" of the upper plate, in which the groove sections are inclined at a first angle a to the direction 7, are partial areas 5d ", 5b", 5d ', 5b 'opposite the lower plate, in which the groove sections are inclined at an angle β; Analogously, partial areas 5b ', 5d', 5b ", 5d" of the upper plate, in which the groove sections run inclined at an angle β, lie opposite areas 5c ", 5a", 5c ', 5a' of the lower plate, in which the groove sections run inclined at an angle a. The wave crests 17 of the upper plate rest only on the ends 21 of the groove sections 12 lying in the partial areas on the wave crests 18 of the lower plate of the plate pair and span the troughs lying between them freely.

The plate 2 shown in FIG. 7c is a modification of the plate 1 according to FIG. 7b, and the wave pattern shown in FIG. 7c is obtained by interchanging the two strips 26, 27 of the wave pattern according to FIG. 7b with one another and twisting the resultant Formed about a geometric axis perpendicular to the plane. This modification can also be produced with a tool, which can be obtained by simply changing the tool used to form a wave pattern according to FIG. 7b. The same applies to the plates to be described according to FIGS. 8b to 13b and 8c to 13c.

By stacking a plate according to FIG. 7b and a plate according to FIG. 7c, a plate pair according to FIG. 7d is obtained, the flow path of which has a higher flow resistance and a different thermal length than the plate pair according to FIG. 7a. The same applies to the plate pairs according to FIGS. 8d to 13d to be formed from plates according to FIGS. 7b to 13b and plates according to FIGS. 8c to 13c in comparison to plate pairs according to FIGS. 8b to 13a.

In this embodiment, flow paths with different properties can also be easily formed in the heat exchanger by a modification of the wave pattern, which can be carried out easily in terms of production technology. However, it is also possible, as explained above in connection with FIGS. 6a and 6b, to construct the heat exchangers with a single plate type, the plates being stacked on top of one another in alternation, rotated by 180 °. A plate stratification can be provided both when building the heat exchangers from a single plate type and when building up from two plate types, in which the mutually identical pairs of exchanger plates have the same position or orientation in the exchanger, as explained in connection with FIGS. 6a to 6d is. In the interest of a uniform flow of the flow properties over the area of the wave pattern, one can see advantageously, e.g. 7d shows an approximately symmetrical position of the crossings or support points 20 'of the groove sections of the wave pattern of such plate pairs.

In the embodiment shown in FIGS. 8a and 8b, the wave pattern of two superimposed exchange plates which form a flow path with one another is formed by subregions which, viewed in the flow direction 7, lie in pairs next to one another and abut one another at separating lines 25 ', 25 "which run in the flow direction In the case shown, eight such subregions 5a to 5h are provided, which form four pairs of subregions. The groove sections 12 present in the individual subregions form, via the dividing lines 25 ', 25 ", adjoining one another, which run from one longitudinal edge 22 of the wave pattern to the other longitudinal edge 23 of the wave pattern, and the groove sections 12 follow one another in a zigzag fashion in the groove trains 24 thus formed. In each case, a pair of groove sections 12a, 12b, which run more obliquely to the flow direction, is followed by a pair of groove sections 12c, 12d, which run less obliquely to the flow direction 7. The tips 16, formed by a pair of the more inclined groove sections 12a, 12b, of one plate (FIG. 8b) of the pair of exchanger plates shown in FIG. 8a are based on the pair of the less inclined groove sections 12c, 12d of the other plate of the Pair of formed tips 31 and vice versa the tips 31 ', which are formed by less inclined groove sections 12c, 12d of the first-mentioned plate, on tips 16', which are embodied by more inclined groove sections 12a, 12b of the second-mentioned plate. The second-mentioned plate, which lies below the first-mentioned plate in the plate pair shown in FIG. 8a, is designed in the same way as the first-mentioned plate according to FIG. 8b and is rotated by 180 ° with respect to the first-mentioned plate. The plate 2 shown in FIG. 8c has a wave pattern 5 'which results from the wave pattern 5 of the plate 1 according to FIG. 8b by interchanging the two halves of the wave pattern 5.

This enables the production of a plate according to FIG. 8c with a tool, which is achieved by slightly modifying a tool used for the production of plates according to FIG. 8b can be obtained. By stacking a plate according to FIG. 8b and a plate according to FIG. 8c, a pair of plates according to FIG. 8d is obtained, in which the wave crests 17 of the one plate not only lie at the tips but also at locations 16 in the middle of the groove sections "Support on shaft crests 18 of the other plate; this results in a different flow resistance and a different thermal length than in the plate pair according to FIG. 8a.

In the embodiment shown in FIGS. 9a and 9b, the wave pattern of the exchanger plates, similarly to the embodiment according to FIGS. 8a and 8b, has a number, namely eight, subareas 5a to 5h which, viewed in the flow direction 7, lie in pairs next to one another and on dividing lines 25 ', 25 ". The groove sections of the partial areas of the wave pattern adjoin one another via the dividing line, which run from one longitudinal edge 22 of the wave pattern to the other longitudinal edge 23 of the wave pattern. In these groove trains, the groove sections follow one another in a zigzag fashion, and at least one pair of groove sections 12a, 12b extending more obliquely to the direction of flow 7 is provided, followed by several pairs of groove sections 12c, 12d which run less obliquely to the direction of flow 7. Analogous to the embodiment according to FIGS Support by strength r oblique groove portions 12a, 12b formed tips 16 are provided on tips 31 of the less oblique groove portions of the other plate of the pair. Between two support points 20 present in a groove train, there are a plurality of groove sections 12 ', which follow the parallel parallel groove sections 12 "of the other plate of the plate pair, wherein there is no mutual support of the plates in these groove sections. In the example shown, this is in the area of the partial areas 5c The modified plate 2 according to Fig. 9c has a wave pattern which results from the wave pattern of the plate 1 according to Fig. 9b by turning around a geometric axis lying in the plate plane. The plate 9c can thus be changed slightly of a tool used for the production of the plate according to Fig. 9. Stacking a plate according to Fig. 9b and a plate according to Fig. 9c leads to a plate pair according to Fig. 9d, which has a higher flow resistance and a different thermal length than that Has plate pair according to Fig. 9a.

In the embodiment according to FIGS. 10a and 10b, the wave pattern of the exchanger plates is formed by two partial areas 5a, 5b lying next to one another in the flow direction, which abut one another on a dividing line 25. The geometric extension 35 of the groove sections 36a of the one partial area 5a coincides at the dividing line 25 with a groove section 36b of the other partial area 5b beginning there and extends from the dividing line 25 to the outer edge 23 of the other partial area 5b parallel to the dividing line 25, this being geometrical Extension 35 of the groove section 36a leaves the groove section 36b at an angle and comes to coincide with a groove section 36b 'adjacent to the groove section 36b. Likewise, the geometric extension 40 of the groove sections 36b of the partial area 5b coincides with a groove section 36a of the partial area 5a starting at the dividing line 25 and extends the groove section 36a obliquely to an adjacent groove section 36a ', with which it extends on the outer edge 22 of the parallel to the dividing line Subarea 5a comes to cover. The upper plate of the plate pair is thus supported with its lower wave vertices 17 of the wave pattern, which are drawn in full lines in FIG. 10 a, at the ends 42 of this wave apex located at the outer longitudinal edges 22, 23 of the wave pattern and along the dividing line 25 located points 41 of this wave crest on the wave crests 18 facing this plate of the underlying plate of the plate pair, these wave crests 18 of the underlying plate of the plate pair, which face the first-mentioned plate, are shown in broken lines in FIG. 10a. The wave pattern of the modified plate 2 shown in FIG. 10c results from the wave pattern of the plate 1 according to FIG. 10b by turning around a geometric axis lying in the plane of the plate and by pivoting about a geometric axis perpendicular to the plane of the plate by 180 °. The plate according to FIG. 10c can thus be produced with a tool which can be obtained by changing over a tool used for producing a plate according to FIG. 10b. Stacking a plate according to FIG. 10b and a plate according to FIG. 10c results in a plate pair according to FIG. 10d. 10b are supported at a plurality of points 43, which are distributed over the length of the groove sections, on the shaft apexes 18 of the underlying plate according to FIG. 10c. Compared to the plate pair according to FIG. 10a, this again results in an increased flow resistance and a different thermal length.

In the embodiment shown in FIGS. 11a and 11b, in the case of both exchanger plates 1 (FIG. 11b) which form a flow path with one another, the groove sections are parts of zigzag-shaped groove trains, the groove sections being approximately perpendicular to one another. The groove sections 45, 46 of the groove trains 47 of the upper plate in FIG. 11a and the groove sections 45 ', 46' of the groove trains 47 'of the lower plate in FIG. 11a have two different lengths, which differ by the width of such a groove. The groove sections 45, 46 of the upper plate of the exchanger plate pair in FIG. 11a overlap each with one groove section of the other plate, that is to say the lower plate in FIG. 11a Plate pairs aligned; a shorter groove section 45 of one plate with a longer groove section 46 'of the other plate and a shorter groove section 45' of the other plate with a longer section 46 of the one plate overlap. In this case, the support is provided in that the lower wave crests 17 of the upper plate shown in full lines in FIG. 11 a are supported only on support points 52 on the wave crests 18 of the lower plates facing the upper plate in FIG. 11 a, which close to the ends of the groove portions of the partial regions 51 of the wave pattern located at the dividing lines 50. The wave pattern of the modified plate 2 shown in FIG. 11c results from the wave pattern of the plate 1 according to FIG. 11b by turning around a geometric axis lying in the plane of the plate and by pivoting around a geometric axis running perpendicular to the plane of the plate by 180 °. This enables a simple manufacture of the plate according to FIG. 11c with a tool, which can be obtained by slight modification from a tool used for the production of plates according to FIG. 11b. Placing a plate according to FIG. 11b and a plate according to FIG. 11c on top of one another results in a plate pair according to FIG. 11d, which has a greater flow resistance and a different thermal length in comparison to the plate pair according to FIG. 11a. In the case of the pair of plates according to FIG. 11d, the wave crests 17 of the upper plate rest on a plurality of points 53 distributed over the longitudinal extent of the groove sections on the wave crests 18 of the lower plate facing the upper plate.

A similar type of support geometry as in the embodiment according to FIGS. 11a and 11b is also present in the embodiment shown in FIGS. 12a and 12b, in which the groove sections 55 parts are zigzagged in the case of both exchanger plates shown in FIG. 12a, forming a flow path with one another are zigzag-shaped grooves 56, the grooves 56 as a whole run in the direction of flow 7, and these grooves 56 of the two plates forming a pair of exchanger plates have identical shape and dimensions; the groove trains 56 of the upper plate are offset in relation to the groove trains 56 'of the lower plate by half a groove width in the flow direction 7. In this embodiment too, the support is carried out similarly to the embodiment according to FIGS. 11a and 11b at points 57 which are located at the ends of the groove sections 55 located at the dividing lines 50 of the partial regions 51 of the wave pattern.

A similar type of support is also given in the embodiment according to FIGS. 13a and 13b, in which, in the case of both exchanger plates which form a flow path with one another, the groove sections 60 are parts of groove trains 61 which run transversely to the flow direction 7, and there are the partial areas 62 of the Wave pattern adjacent to each other, in the flow direction 7 surface strips with different widths; the groove trains 61 of the upper plate are offset in relation to the groove trains of the lower plate of the plate pair to form mutual support points 63 in the flow direction 7 and transversely to the flow direction. The support points 63 lie, similar to the embodiments according to FIGS. 11 a and 12 a, in the vicinity of the ends of the groove sections 60 located at the dividing lines 64.

The wave pattern of the modified plate 2 belonging to the embodiment according to FIGS. 12a and 12b and shown in FIG. 12c results from the wave pattern of the plate 1 according to FIG. 12b by simply shifting in the flow direction 7. Stacking a plate according to FIGS. 12b and a plate according to FIG. 12c results in a plate pair according to FIG. 12d. This has a higher flow resistance and a different thermal length than the plate pair according to Fig. 12a. In the pair of plates according to FIG. 12d, the wave crests 17 of the one plate rest not only on the ends 57 of the groove sections, but also at locations 58 in the middle of the groove sections on the shaft crests 18 of the other plate of the plate pair.

The wave pattern of the modified plate shown in FIG. 13c, which belongs to the embodiment according to FIGS. 13a and 13b, results from the wave pattern of the plate according to FIG. 13b by interchanging the two halves of the wave pattern which follow one another in the flow direction 7. Placing a plate according to FIG. 13b and a plate according to FIG. 13c on top of one another results in a plate pair according to FIG. 13d, which has a higher flow resistance and a different thermal length in comparison to a plate pair according to FIG. 13a. The wave crests 17 of the longer groove sections of one plate of this pair of plates lie at their ends 63 and at points 65 in the middle of their longitudinal extent on the wave crests 18 of this plate pair facing this plate.

Those described above in connection with the individual embodiments and e.g. Modified plates shown in FIGS. 8c to 13c, as is the case with the plate pairs according to FIGS. 6a to 13a, can be stacked in pairs to form plate pairs with a low flow resistance, one plate being opposite the other plate of such a plate pair a geometric axis perpendicular to the plate plane is rotated by 180 °. A structure according to FIG. 3 or an exchanger with mutually identical plates, which are rotated on one another alternately, can be obtained in this way.

Claims (16)

1. A plate heat-exchanger comprising at least three exchanger plates (1, 2) arranged in layers one upon the other, each two consecutive exchanger plates together forming a flow path (3, 4), the said exchange plates (1, 2) consisting of sheet metal and, in order to form flow passages between the plates (1, 2) and for their mutual support, being provided with an impressed pattern (5) of corrugations covering the flow path, said pattern forming grooves (9, 10) extending transversely of the direction of corrugation and at an angle to the flow centre-line (7), the surface of the corrugation pattern (5) of each exchange plate (1, 2) consisting of a number of contiguous sub-zones (5a, 5b, 5c, 5d), the grooves (9, 10) in the individual sub-zones each forming a group of parallel groove portions (12) terminating at the boundaries of the associated sub-zone, and the groups of groove portions (12) of different sub-zones (5a, 5b, 5c, 5d) extend at an angle to one another, and there is disposed opposite and in alignment with each sub-zone of the corrugation pattern (5) of an exchanger plate (1) an equally large sub-zone of the corrugation pattern of another exchanger plate (2) forming a flow path (3, 4) with the first-mentioned plate, characterised in that the crests (17) of the corrugations of one plate of at least one pair of exchanger plates (1, 2) together forming a flow path (3, 4) are supported only in the zone of the ends (21) of the groove portions (12) of said plate at the opposite corrugation crests (18) of the other plate of the pair, again in the zone of the ends (21) of the groove portions (12) of the said other plate, and freely span the distance between these points of support (20).

2. A plate heat-exchanger according to claim 1, characterised in that those corrugation crests (17) of one exchanger plate (1) of a pair together forming a flow path which extend along groove portions (12; 12a-12d; 12', 12"; 36a, 36b) of the sub-zones (5a-5d; 5a'-5d'; 5a"-5d"; 5a-5h; 5a, 5b) of the corrugation pattern (5, 5'), which corrugation crests face the other plate of this pair, are supported by one end (21) at the end (21) of a corrugation crest (18) of the other plate (1) facing the first-mentioned plate and, by their other end, at the end of a parallel corrugation crest (18) of the other plate adjacent the latter corrugation crest (18), and freely span the trough groove of the corrugation pattern of the other plate situated therebetween.

3. A plate heat-exchanger according to claim 1, characterised in that the corrugation pattern of the exchanger plates (1, 2) is formed by more than two sub-zones (5a-5h) abutting at parting lines, the groove portions (12a-12d) forming contiguous groove lines (24) via the parting lines (25', 25"), and in that in the course of such groove lines (24) there are situated between a point of support (20) situated in one groove portion and a point of support (20) situated in another groove portion one or more groove portions (12', 12") in which the groove lines of the two plates of a pair follow one another and extend without mutual support.

4. A plate heat-exchanger according to claim 2, characterised in that the corrugation pattern (5, 5') of the exchanger plates (1, 2) comprises an even number of consecutive sub-zones (5a-5d; 5a'-5d'; 5a"-5d"; 5a-5h; 5a, 5b) in or transversely of the direction of flow (7), the groove portion (12; 12a, 12b; 36a, 36a') in one half of the number of sub-zones extending at a first angle (a) to the direction of flow while in the other half of the number of sub-zones the groove portions (12; 12c, 12d; 36b, 36b') extend at a second angle (a) to the direction of flow (7), the lengths (29) of the individual sub-zones as measured in the direction of the succession of sub-zones (5a, 5b, 5c, 5d) being equal, and when an exchanger plate of this kind has superimposed thereon a second identically constructed heat-exchanger plate turned through 180° about an axis perpendicular to the geometric centre (30) of the plate the sub-zones (5a, 5b) having groove portions of the one plate (1) extending at the first angle (a) to the direction of flow are situated opposite the sub-zones having groove portions in the other plate (2) extending at the second angle (β) to the direction of flow (7), and those corrugation crests (18) of the corrugation pattern of the second said plate which face the first-mentioned plate (1) in the individual sub-zones (5c, 5d) of the corrugation pattern come to bear only at the ends (21) of the groove portions (12) of the individual sub-zones (5a, 5b, 5c, 5d) on the corrugation crests (17) of the corrugation pattern of the first-mentioned plate (1) facing the second said plate.

5. A plate heat-exchanger according to claim 4, characterised in that the corrugation pattern of the exchanger plates (1, 2) comprises a number of sub-zones (5a', 5b', 5c', 5d', 5a", 5b", 5c", 5d") divisible by four and situated in two surface strips (26, 27) separated by a parting line (25) extending in or transversely of the direction of flow (7), the corrugation pattern being of mirror-image symmetry in respect of the parting line (25) between the two surface strips (26, 27).

6. A plate heat-exchanger according to claim 2, characterised in that the corrugation pattern (5, 5') of the exchanger plates (1, 2) is formed by four or more sub-zones (5a-5h) which, as considered in the direction of flow (7), are disposed side by side in pairs and abut at parting lines (25', 25"), the groove portions (12a, 12b) forming groove lines which are contiguous via the parting lines (25', 25") and which extend from one longitudinal edge (22) of the corrugation pattern (5) to the other longitudinal edge (23) of the corrugation pattern (5), the groove portions (12a, 12b, 12c, 12d) being disposed consecutively zig-zag fashion in the groove lines (24) and each pair of groove portions (12a, 12b) extending at a greater angle to the direction of flow (7) is followed by a pair of groove portions (12c, 12d) extending at a lesser angle to the direction of flow (7) and the apices (16) of the groove portions (12a, 12b) of one (1) of a pair of exchanger plates extending at a greater angle are supported on the apices (31) of the groove portions (12c, 12d) of the other plate (2) of this pair extending at a lesser angle and conversely the apices (16') of the groove portions (12a, 12b) of the other plate (2) of a pair extending at a greater angle are supported on the apices (31') of the groove portions (12c, 12d) of one plate (1) of the pair extending at a lesser angle.

7. A plate heat-exchanger according to claim 3, characterised in that the corrugation pattern of the exchanger plates is formed by four or more sub-zones (5a-5h) which, as considered in the direction of flow (7), are disposed side by side in pairs and abut at parting lines (25', 25"), the groove portions (12a, 12b, 12c, 12d) forming groove lines (24) which are contiguous via the parting lines (25', 25") and which extend from one longitudinal edge (22) of the corrugation pattern (5) to the other longitudinal edge (23) of the corrugation pattern (5), the groove portions being disposed consecutively zig-zag fashion and at least one pair of groove portions (12a, 12b) extending at a greater angle to the direction of flow (7) is provided and is followed by a plurality of pairs of groove portions (12c, 12d) extending at a lesser angle to the direction of flow and the apices (16) of the groove portions (12a, 12b) of one (1) of a pair of exchanger plates extending at a greater angle are supported on apices (31) of the groove portions (12c, 12d) of the other plate (2) of the pair extending at a lesser angle and the apices (16) of the groove portions of the other plate of the pair extending at a greater angle are supported on the apices (31) of the groove portions of one plate of the pair extending at a lesser angle, and in that between the points of support (20) in the course of a groove line there are disposed a plurality of groove portions (12') which follow parallel groove portions (12") of the other plate of the exchanger plate pair and in which there is no mutual suport between the two plates of the pair.

8. A plate heat-exchanger according to claim 2, characterised in that the corrugation pattern of the exchanger plates is formed by two sub-zones (5a, 5b) which, as considered in the direction of flow (7), are situated side by side and abut at a parting line (25), the geometric extension (35) of the groove portions (36a) of one sub-zone (5a) being coincident at the parting line (25) with a groove portion (36b) starting there in the other sub-zone (5b) and, leaving this groove portion (36b) at an angle, being coincident, at the outer edge (23) of the other sub-zone (5b) parallel to the parting line (25), with a groove portion (36b') adjacent said groove portion (36b) and similarly the geometric extension (40) of the groove portions (36b) of the other sub-zone (5b) is coincident, at the parting line (25), with a groove portion (36a) starting there in one sub-zone (5a) and, leaving this groove portion (36a) at an angle, is coincident, at the outer edge (22) of one sub-zone (5a) parallel to the parting line (25), with a groove portion (36a') adjacent said groove portion (36a) and in that the two plates of an exchanger plate pair support one another mutually at these points of coincidence.

9. A plate heat-exchanger according to claim 1, characterised in that the groove portions (45, 46, 45', 46') of two exchanger plates together forming a flow path are parts of groove lines (47, 47') extending zig-zag fashion, the zig-zag groove portions (45, 46, 45', 46') preferably extending approximately perpendicularly to one another, in that the groove portions of the groove lines (47, 47') have two different lengths which differ by the width of one or two grooves, and in that the groove portions (45, 46) of one plate of the exchanger plate pair each overlap in alignment with one groove portion of the other plate, while in each case a shorter groove portion (45) of one plate is overlapped by a longer groove portion (46') of the other plate and a shorter groove portion (45') of the other plate is overlapped by a longer groove portion (46) of the one plate.

10. A plate heat-exchanger according to claim 1, characterised in that the groove portions (55) of two exchanger plates together forming a flow path are parts of groove lines (56) which extend zig-zag fashion, said groove lines (56) extending in the direction of flow (7) and the groove lines (56,56') of the two plates of a pair having identical shapes and dimensions, and the groove lines (56) of one plate are offset, with respect to the groove lines (56') of the other plate, by half a groove width in the direction of flow (7).

11. A plate heat-exchanger according to claim 1, characterised in that the groove portions (60) of two exchanger plates together forming a flow path are parts of groove lines (61) extending zig- zag fashion transversely of the direction of flow (7), the sub-zones (62) of the corrugation pattern being adjacent surface strips of different widths extending in the direction of flow (7) and the groove lines (61) of one plate (1) of a pair are offset from the groove lines of the other plate (2) of said pair in order to form mutual points of support (63) in and transversely of the direction of flow (7).

12. A plate heat-exchanger according to any one of claims 1 to 11, characterised in that the said pairs of exchanger plates together forming a flow path are formed from two identical plates and one plate of such pair is pivoted, with respect to the other plate of the pair, through 180° about a geometric axis extending through the geometric centre (30) of the plates perpendicularly to the plate plane.

13. A plate heat-exchanger according to claim 12, characterised in that two different types of exchanger plates are provided in the heat exchanger and each pair of exchanger plates of the same type are disposed one upon the other to form a flow path for one medium and the different pairs of exchanger plates follow one another alternately, and a flow path for the other medium is formed in each case between the contiguous exchanger plates of different constructions of consecutive pairs of exchanger plates, the groove portions of the corrugation patterns of one plate of two adjoining exchanger plates of different constructions extending crossingly over a plurality of groove portions of the other of these two exchanger plates and the corrugation crests of the groove portions of one plate bear on the opposite corrugation crests of the other plate at a plurality of points of contact distributed over the length of the groove portions.

14. A plate heat-exchanger according to claim 13, characterised in that the corrugation pattern of one exchanger plate type is geometrically related to the corrugation pattern of the other exchanger plate type, one pattern arising out of the other by pivoting through 180° about a geometric axis situated in the plane of the pattern and preferably extending through the centre (30) thereof and/or by changing over sub-zones of the pattern.

15. A plate heat-exchanger according to claim 13 or 14, characterised in that the crossings of the groove portions of the corrugation pattern of two contiguous plates together forming a flow path are disposed approximately symmetrically in relation to a centre line of the plates situated approximately in the plate plane.

16. A plate heat-exchanger according to any one of claims 13 to 15, characterised in that the mutually identical pairs of exchanger plates have the same positions or orientations in the exchanger.

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