SE193486C1

SE193486C1 -

Info

Publication number: SE193486C1
Authority: SE
Publication date: 1964-01-01

Description

Uppfinnare: P S Knudsen Prioritet begard frem den 13 oldober 1955 (Danmark) Foreliggande uppfinning avser ett forfarande for varmeoverfOring mellan tva strommande medier, som vart for sig sasom medium-strain ledas genom av tvh vid sidan av varandra belagna korrugerade och inbordes parallella varmevaxlingsplattor begransade kanaler, varvid en mediumstrom under passagen genom en kanal bibringas riktningsandrande impulser, som frail kanalvaggarna bibringas mediumstrommen fordelad Over stromningskanalens bredd i flera vid sidan av varandra beldgna impulser. Uppfinningen avser ocksa en varmevaxlare for forfarandets genomfOrande. Inventor: PS Knudsen Priority requested on 13 October 1955 (Denmark) The present invention relates to a method for heat transfer between two flowing media, each of which is guided as a medium-strain through channels corroded by two side-by-side corrugated and inboard parallel heat exchange plates. , whereby a medium flow during the passage through a channel is imparted to direction-changing impulses, which from the channel cracks are imparted to the medium flow distributed over the width of the flow channel in several adjacent pulses. The invention also relates to a heat exchanger for carrying out the process.

For att uppna effektiv och likformig marineoverforing mellan de strommande medierna iir det onskvart att bibringa medierna en turbulent rorelse. Harigenom onskar man forhindra att vissa skikt av mediestrommen rora sig med fOrsprang framfor andra skikt av denna strom. Genom turbulens kan man oak-sit undvika fastbranning av mediet ph plattorna. In order to achieve efficient and uniform marine transfer between the flowing media, it is desirable to give the media a turbulent motion. In this way, it is desired to prevent certain layers of the media stream from moving with an advantage over other layers of this stream. Due to turbulence, one can also avoid burning of the medium ph plates.

Da varmevaxlingsplattor i allmanhet bestii av ett dyrbart material, i de fiesta fall ay rostfritt stal, ãr det av ekonomiska skill onskvart att den disponibla varmevaxlingsytan pit varje platta under givna forhallanden utformas sit stor som mojligt. Since heat exchange plates generally consist of an expensive material, in most cases of stainless steel, it is economically important that the available heat exchange surface of each plate under given conditions is designed to be as large as possible.

Det dr kant att framkalla turbulens roedelst atgarder, som samtidigt medfora ett vasentligt tryckfall i de genom kanalerna passerande mediestrommarna. Andamalet med uppfinningen är att ange, huru en optimal varmeoverfOring vid givna forhallanden skall krinna astadkommas, dvs. sit att man samtidigt med sit stor varmevaxlingsyta som mOjligt under genomstromningen genom kanalerna mellan plattorna uppnar sit stor turbulens som mojligt i medierna samtidigt som tryckfallet blir sit ringa som mojligt. It tends to provoke turbulence in the process, which at the same time causes a significant drop in pressure in the media streams passing through the channels. The object of the invention is to state how an optimal heat transfer in given conditions is to be achieved, i.e. At the same time as its large heat exchange surface as possible during the flow through the channels between the plates, it achieves its large turbulence as possible in the media at the same time as the pressure drop becomes as small as possible.

Dena andamal uppnas enligt uppfinningen genom att varje impuls ar sammansatt av en i riktning av plattans plan och en tvars mot plattans plan svangande komposant och att fran motsatta sidor am kanalvagarna kommande impulser verka i riktningar, som korsa varandra, sett i huvudstrOmsriktningen, samt att storleken av hela mediestrommens tvarsektionsarea i en kanal pa alla stallen utmed kanalens stromninglangd Mlles huvudsakligen konstant. Under stromningen genom kanalerna bli medierna salunda kraftigt omvirvlade i ett snettliggande plan och korsa samtidigt varandra, varigenorn mycket effektiv genomvirvling erhalles. Da nagra skadliga fortrangningar av genonastromningsarean icke upptrada, undgas ovannamnda tryckfall tinder mediernas stromning genom plattmellanrummen. These objects are achieved according to the invention in that each impulse is composed of a component oscillating in the direction of the plane of the plate and a component transverse to the plane of the plate and that impulses coming from opposite sides of the channel waves act in directions which intersect, seen in the main current direction, and that the magnitude of the entire cross-sectional area of the media stream in a channel on all stalls along the flow length of the channel Mlles is substantially constant. During the flow through the channels, the media are thus strongly swirled in an inclined plane and at the same time cross each other, whereby very efficient vortexing is obtained. Since some harmful displacements of the genona flow area did not occur, the above-mentioned pressure drop is avoided as the flow of the media through the plate gaps.

Sarskilt effektiv och Over hela den genomstrommande ytan ensartat fordelad genomvirvlin.g ay mediumstrommen kan enligt uppfinningen uppnas genom att impulserna utmed stromningskanalernas langd for varje kanalvagg folja i sidled forlopande sicksacklinjer, som for de frail den ena kanalvaggen pit mediumstrommen inverkande impulserna liipa I motsatt riktning mot sicksacklinjerna for de fran den andra kanalvaggen pa mediumstrOmmen inverkande impulserna samt korsa dessa utmed kanallangden med regelbunden upprepning mellan varje vandpunkt hos vagrorelsen. 2— — En for genomforande av namnda forfarande lampad varmevaxlare kan besta av ett antal inbordes parallella och pa inbordes avstand frail varandra anbragta plattor, vilkas ytor aro forsedda med en i huvudsak tvars mot stromriktningen forlopande grupp av vagformiga -veck, och vid vilka utskjutande delar av vecken i en platta ingripa i av vecken begransade vagdelar i angransande platta. Enligt uppfinningen kannetecknas denna varmevaxlare av att de vagformiga vecken hos hada plattorna i ett plattpar aro overlagrade av en annan grupp veck, som bildas av i stromningsriktningen i sicksack forlOpande veck, varvid plattornas sicksackformationer aro identiska men orienterade motsatt i forhallande till en axel vinkelratt mot plattans plan pa sadant sail, att den ena plattans sicksackveck i ett plattpar upprepade ganger korsa den andra plattans mitt emot belagna sicksaekveck, och att kanaltvarsektionens area pa alla stallen utmed stromningskanalens langd har i huvudsak konstant storlek. The medium flow can be achieved according to the invention by the impulses along the length of the flow channels for each channel wall following laterally extending zigzag lines, which for the frail one channel wall pit the medium flow acting towards the medium flow. the zigzag lines for the impulses from the second channel wall on the medium current and cross these along the channel length with regular repetition between each water point of the wave motion. A heat exchanger for carrying out the aforesaid process may consist of a number of plates parallel to each other and spaced apart from each other, the surfaces of which are provided with a group of wavy folds extending substantially opposite to the current direction, and at which projecting parts of the folds in a plate engage in the part of the wagon delimited by the folds in the adjacent plate. According to the invention, this heat exchanger can be characterized in that the wavy folds of the plates in a pair of plates are superimposed by another group of folds formed by zigzagging folds in the flow direction, the plates' zigzag formations being identical but oriented opposite in relation to an axis perpendicular to the plate. plan on such a sail, that the zigzag fold of one plate in a pair of plates repeatedly crosses the zigzag folds opposite the other plate, and that the area of the duct section in all places along the length of the flow channel has a substantially constant size.

Vid en varmevaxlare dar veckningen av ytorna hos ett plattpars plattor i stromningsriktningen upprepas periodiskt, sit att den av plattorna begransade kanalens geometriska tvarsektionsform sett i stronniktningen periodiskt fOrandrar utseende fran en gransform till en annan, kan en valavstyvad konstruklion enligt uppfinningen astadkommes genom att plattorna med veckryggar anliaga mot varandra pa stallen dar kanaltvarsebktionen har en av sina gransformer. In a heat exchanger where the folding of the surfaces of a pair of plates in the flow direction is repeated periodically, provided that the geometric cross-sectional shape of the channel delimited by the plates seen in the direction of the period periodically changes appearance from one spruce shape to another, a whale stiffened construction according to the invention abut against each other in the places where the channel cross section has one of its spruce shapes.

For uppfinningens genomforande fir det vi-dare lampligt att de i stromningsriktningen forlopande vecken pit de tva plattorna i ett plattpar ha samma djup. En intensiv och tat genomvirvling kan enlist uppfinningen sarskill uppnas genom att vandpunkterna pa sicksacklinjerna till plattornas i stromningsriktningen fOrlopande veck omvaxlande ligga pa asarna resp. dalarna av plattornas Overlagrade tvarveck. For the practice of the invention it is furthermore appropriate that the folds extending in the direction of flow pit the two plates in a pair of plates have the same depth. An intensive and rapid vortex can only be achieved according to the invention in that the water points on the zigzag lines to the folds of the plates in the direction of flow alternately lie on the axes resp. the valleys of the slabs' superimposed transverse folds.

Vid ett jamforande fors& mellan en varmevaxlare med pa sistnamnda satt utformade och anbragta plattelement och en. varmevaxlare med plattelement, som endast ha i elementens tvarriktning forlopande, ribbformiga uppressningar, vilka begransa delkanaler, har det visat sig att tryckforlusten i en plattstapel eller ett plattpaket, uppbyggt av plattor enligt uppfinningen blir 20-25 % mindre an i plattpaket, som uppbyggts av de namnda kanda plattelementen. I hada fallen voro fOrsoksforhallandena lika, i det att samma antal plattelement i de tvit plattpaketen anvandes samt roranslutningarna anordnades pa sadant salt, att de tva plattpaketen komma att arbeta under exakt samma betingelser. In a comparative process between a heat exchanger with plate elements designed and arranged on the latter and one. heat exchangers with plate elements, which have only rib-shaped recesses extending in the transverse direction of the elements, which delimit sub-channels, it has been found that the pressure loss in a plate stack or a plate package built up of plates according to the invention is 20-25% less than in plate packages the named kanda plate elements. In all cases the test conditions were the same, in that the same number of plate elements in the two plate packages were used and the pipe connections were arranged on such a salt that the two plate packages would work under exactly the same conditions.

Den namnda mindre tryckforlusten vid plattpaketet enligt uppfinningen mojliggjorde en Okning av mangden av det genomstrommande mediet. Den darigenom uppnadda ok ningen av varmeOverfOringen i forhallande till varmeoverforingen vid den kanda anordningen var 10-12 %. The said smaller pressure loss with the plate package according to the invention made it possible to increase the amount of the flowing medium. The resulting increase in heat transfer in relation to the heat transfer at the known device was 10-12%.

De forsok, som givit ovannananda resultat, ha genomforts med mediummangder av nor- mal storlek. Forsoken ha darefter utvidgals till att a.ven omfatta sma mediummangder. Vid dessa forsok har det visa sig, att resulta- ten vid den namnda, enligt uppfinningen utformade varmevaxlaren voro annu gynnsammare jamfOrt med resultaten vid den kanda varmevaxlaren an am man arbetade med mediummangder av normal storlek. The experiments, which have given the above-mentioned results, have been carried out with medium quantities of normal size. The experiments have since been extended to also include small amounts of medium. In these experiments it has been found that the results of the said heat exchanger designed according to the invention were even more favorable in comparison with the results of the known heat exchanger when working with medium quantities of normal size.

Sistnamnda effekt ar sarskilt gynnsam i de fall, da den enligt uppfinningen utformade varmevaxlaren anvandes for pastbrisering av gradde, dvs. utformas som en apparat med liten kapacitet, enar sadana apparater icke endast ha ringa kapacitet utan a.ven kunna utsattas for arbetsbetingelser, dar kapaciteten kan variera med upp till 50 O. The latter effect is particularly favorable in cases where the heat exchanger designed according to the invention is used for pasteurization of degrees, ie. is designed as a device with a small capacity, such devices not only have low capacity but can also be exposed to working conditions, where the capacity can vary by up to 50 O.

Om man skall forsoka uppna en motsvarande god varmeoverforing medelst endast i en riktning av plattelementen forlopande vag- formiga yea, blir det nodvandigt att utforma dessa pa sadant salt, att vasentliga for- trangningar av genomstromningsarean upp- sta, vilket skulle medfora vasentliga tryckforluster i mediumstrommen. Vid en kand kon- struktion av delta slag är det salunda for uppnaende av kraftig turbulens nodvandigt att lata genomstromningsareans storlek variera i forhallandet 1:4. If an attempt is to be made to achieve a correspondingly good heat transfer by means of wavy surfaces extending only in one direction of the plate elements, it becomes necessary to design these on such a salt that substantial narrowings of the flow area arise, which would entail significant pressure losses in the medium flow. . In the case of a known construction of the delta type, it is therefore necessary to allow the size of the flow-through area to vary in the ratio 1: 4 in order to achieve strong turbulence.

Uppfinningen shall i det foljande beskrivas nfirmare med hanvisning till bifogade rit- ningar, dar fig. 1 i perspektiv visar delar av tva likartat utformade, Over varandra lagda viirmevaxlarplattor, vilka hada aro forsedda med sival i stromnings- resp. langdriktning- en forlopande, varandra overlagrande vagformiga veckgrupper, av vilka de i stromnings- resp. langdriktningen forlOpande vecken sick- sackformigt stracka sig mot varandra frau platta till platta. Fig. 2 ar en sektion enligt linjeni fig. 3, vilken sistnamnda figur visar en. del av ett plattpar enligt fig. 1, sedd uppifran. Fig. 4 ar en sektion enligt linjen IV—IV i fig. 3, fig. 5 en sektion enligt linjen V—V i fig. 3, fig. 6 en sektion enligt linjen VI —VI i fig. 3, fig. 7 en sektion enligt linjen VII—VII i fig. 3, fig. 8 en sektion enligt linjen VIII—VIII i fig. 3, fig. 9 en sektion enligt linjen IX—IX i fig. 3 och fig. 10 en sektion enligt linjen X—X i fig. 3. The invention will be described in more detail below with reference to the accompanying drawings, in which Fig. 1 shows in perspective parts of two similarly designed, superimposed heat exchanger plates, which were provided with a rival in flow resp. longitudinal - a continuous, superimposed vaginal fold groups, of which those in flow- resp. the longitudinal direction The continuous folds zigzag-shaped stretch towards each other from plate to plate. Fig. 2 is a section along the line of Fig. 3, the latter figure showing one. part of a pair of plates according to Fig. 1, seen from above. Fig. 4 is a section along the line IV — IV in Fig. 3, Fig. 5 a section along the line V — V in Fig. 3, Fig. 6 a section along the line VI —VI in Fig. 3, Fig. 7 a section along the line VII — VII in Fig. 3, Fig. 8 a section along the line VIII — VIII in Fig. 3, Fig. 9 a section along the line IX — IX in Fig. 3, and Fig. 10 a section along the line X— X in Fig. 3.

Fig. 1 visar delar av tva varmevaxlarplattor 10 och 12, som aro lagda Over varandra for att bilda genomstromningskanaler. Varje plat- ta ar forsedd med en grupp av i plattans tvarriktning forlopande, tatt vid sidan av varandra liggande, vagformiga veck 14 och en grupp av i plattans stromnings- resp. langdriktning farlopande tatt vid sidan av varandra liggande, vagformiga veck 16. Vecken i varje grupp stracka sig parallellt med varandra. Vecken — —3 16 i varje platta stracka sig vidare i sin langdriktning sicksackformigt och overlagra vec- ken 14 varvid sicksacklinj ens andpunkter om- vaxlande ligga pa veckens 14 Oversta och nedersta partier. De langsgaende veckens 16 sicksackforlopp är fran platta till platta ut- format motlopande, sá att den ena plattans langsgaende vagor 16 upprepade ganger korsa angransande plattas langsgaende veck. I ovrigt stracka sig tvarveckens 14 ryggar pa en platta in i de genom tvarvecken. 14 i angransande platta bildade ryggarna eller asarna. Vecken 16 i bada plattorna ha samma djup. Fig. 1 shows parts of two heat exchanger plates 10 and 12, which are laid on top of each other to form flow channels. Each plate is provided with a group of wavy folds 14 extending in the transverse direction of the plate, taken side by side, and a group of flowing resp. longitudinal runway taken side by side, wavy folds 16. The folds in each group extend parallel to each other. The folds - —3 16 in each plate extend further in their longitudinal direction zigzag-shaped and overlay the folds 14, the zigzag line's points alternating lying on the 14 upper and lower parts of the fold. The longitudinal folds of the longitudinal folds 16 of zigzag are flattened from plate to plate, so that the longitudinal curves of one plate 16 repeatedly cross the longitudinal folds of the adjacent plate. Otherwise, the 14 backs of the transverse fold extend on a plate into those through the transverse folds. 14 in adjacent plate formed the ridges or aces. The folds 16 in the bath tiles have the same depth.

Genom denna anordning uppnas att det nedersta partiet av varje pa den oversta plattan 10 utformad sick-sackkorrugering, som bildas av tva langstrackta, i vinkel mot varandra anordnade deformeringar 18 och 20, ligger pa ryggen av en motsvarande sicksackkorrugering pa den nedersta plattan 12, sâ att varje sicksackkorrugering 18, 20 stodes vid fyra punkter pa den underliggande plattan (se fig. 3), dar stodpunkterna for siasackkorrugeringarna i plattan 10 aro betecknade med S. Sicksackkorrugeringarnas toppunkter aro betecknade med T. Tack vare sitt ingrepp i varandra dragas varmevaxlarnas plattor under hopspanningen, sett i plattornas langdriktning, ihop pa avsedd plats. Plattorna aro med andra ord sjalvinstallande i langdriktningen for mediernas stromning, med hansyn till sitt inbordes lage. Vid den visade anordningen ligga sicksackkorrugeringarnas toppunkter pa de pa varandra lagda plattorna Over varandra. En inbordes forskjutning av plattorna tvars mot strOmningsriktningen medf Or endast att dessa toppunkters inbordes lage fOrandras fran platta till platta titan att plattornas in-hordes avstand darvid forandras. By means of this device it is achieved that the lower part of each zigzag corrugation formed on the upper plate 10, which is formed by two elongate, angularly arranged deformations 18 and 20, lies on the back of a corresponding zigzag corrugation on the lower plate 12, so that each zigzag corrugation 18, 20 stood at four points on the underlying plate (see Fig. 3), where the standpoints of the zigzag corrugations in the plate 10 are denoted by S. The vertex zigzag peaks are denoted by T. Due to their engagement with each other, the plates of the heat exchangers are pulled under the clamping, seen in the longitudinal direction of the plates, together in the intended place. In other words, the plates are self-installing in the longitudinal direction of the flow of the media, with a view to their inboard layer. In the device shown, the top points of the zigzag corrugations lie on the superimposed plates. An on-board displacement of the plates transverse to the direction of flow only means that the in-law of these inputs changes from plate to plate titanium, that the distance of the plates' in-horns thereby changes.

Genomstromningsriktningen for sektionerna enligt fig. 2 och 4-6 stracker sig vinkelratt mot ritningsplanet, medan genomstromningsriktningen for sektionerna enligt fig. 3 och 7-9 visas med pilar. The flow direction of the sections according to Figs. 2 and 4-6 extends perpendicular to the plane of the drawing, while the flow direction of the sections according to Figs. 3 and 7-9 is indicated by arrows.

Den i fig. 6 visade sektionen stracker sig genom en rad stodpunkter S. Den i fig. 4 visada sektionen ligger mittemellan tva rader stodpunkter medan den i fig. 5 visade sektionen ligger mellan sektionerna enligt fig. 4 och 6. De mellan plattorna bildade kanalerna A i samtliga sektioner ha praktiskt taget lika stor tvarsektionsarea. Daremot kommer kanaltvarsektionens geometriska form att andras fran fig. 4-6 och omvant. Den genom plattorna begransade kanalens geametriska tvarsektionsformer forandra i stromningsriktningen periodiskt sitt utseende frail en gransform till en. annan. Var och en av de visade plattornas veckgrupper strava att var for sig bibringa det strommande mediet riktningsandrande impulser, och av ritningen framgar, att var och en av dessa impulser ar sammansatt av en i plat-tans plan svangande och en vinkelratt mot detta plan svangande komponent och att frail motsatta sidor av kanalvaggen kommande im- pulser verka i riktningar, som korsa strom- ningsriktningen, varigenom en turbulens uppstar, utan att flagon andring av tvarsektions- areans storlek for hela mediumstrommen ge- nom kanalen eller stromningshastigheten erfordras. Turbulensverkan paverkar hell: vat- skestrommen, varigenom en icke onskad forsprangsrorelse av ett vatskeskikt f6re ett annat forhindras. The section shown in Fig. 6 extends through a row of standing points S. The section shown in Fig. 4 lies between two rows of standing points, while the section shown in Fig. 5 lies between the sections according to Figs. 4 and 6. The channels formed between the plates A in all sections have practically equal cross-sectional area. In contrast, the geometric shape of the ductwork section will be different from Figs. 4-6 and vice versa. The geometric cross-sectional shapes of the channel delimited by the plates periodically change their appearance periodically from one spruce shape to another in the direction of flow. Other. Each of the folding groups of the plates shown struggles to impart directionally changing impulses to the flowing medium, and the drawing shows that each of these pulses is composed of a component pivoting in the plane of the plate and a component pivoting perpendicular to this plane. and that impulses coming from opposite sides of the channel wall act in directions which cross the flow direction, whereby a turbulence arises, without the need to change the size of the cross-sectional area for the entire medium flow through the channel or the flow velocity. The effect of turbulence has a positive effect: the liquid stream, whereby an undesired advance movement of one layer of liquid before another is prevented.

Forandringen av tvarsektionsformen, t. ex.. fran den i fig. 4 till den i fig. 6 visade formen och tillbaka till formen enligt fig. 4 sker fyra ganger, da vatskan ror sig frail en vagtopp T till nasta vagtopp. Vid en utforingsform av de visade plattorna kan vagbredden for tvarvagorna 14 vara 40 mm. Vid normal genomstromningshastighet av c :a 0,5 m/sek kommer salunda den periodiska forandringen av tvarsektionsformen att ske med en frekvens av c:a 50 perioder/sek. Periodtalet for'cle genom de sicksackformiga langdvecken 16 orsaliade svangningarna am c:a 12 perioder/sek. Det beror antagligen pa mojligheten att man kan uppna ett hogt periodtal, att en kraftig turbulensverkan aven erhalles vid smtt strOmningshastigheter. The change of the cross-sectional shape, for example, from the shape shown in Fig. 4 to the shape shown in Fig. 6 and back to the shape according to Fig. 4 takes place four times, as the liquid moves from a carriage top T to the next carriage top. In an embodiment of the plates shown, the carriage width of the carriage carriages 14 can be 40 mm. At a normal flow rate of about 0.5 m / sec, the periodic change of the cross-sectional shape will thus take place at a frequency of about 50 periods / sec. The period count for'cle through the zigzag-shaped long folds 16 caused the oscillations am about 12 periods / sec. This is probably due to the possibility that a high period number can be achieved, that a strong turbulence effect is also obtained at low flow rates.

Om plattornas läge i forhallande till varandra andras sO. att den ena plattan forskjutes i tvarriktningen i forhallande till det andra plattelementet, komma de i fig. 4-6 visade sektionerna att Andra sitt lage men forbli i ovrigt of or andrade. About the position of the plates in relation to each other sO. that one plate is displaced in the transverse direction in relation to the other plate element, the sections shown in Figs. 4-6 show that Andra is its own but remains otherwise of other.

Claims

Patent claim:

1. A method for heat transfer between two flowing media, each of which is conducted as a medium stream through two adjacent corrugated corrugated channels and delimited by parallel heat exchange plates, a medium stream being imparted directionally changing impulses during the passage through a channel, which from the channel cradles are imparted to the medium stream distributed over the width of the flow channel in several side by side and along the length of the flow channel in several successive pulses, characterized in that each pulse is composed of a component oscillating in the direction of the plate plane and sides of the channel waves impulses coming act in directions, which cross each other, seen in the main flow direction, and that the size of the entire cross-sectional area of the media stream in a channel on all stalls along the flow length of the channel Wiles is substantially constant.

2. A method according to claim 1, characterized in that the pulses along the length of the straining channels for each channel wall follow laterally flowing zigzag lines, which - for the impulses acting from one channel wall on the medium current run in the opposite direction to the zigzag lines on the medium currents influencing the impulses and crossing them along the channel length with regular repetition between each water point of the wave motion.

Heat exchanger for carrying out the method according to claim 1 or 2 consisting of a number of inboard parallel and spaced apart plates, the surfaces of which are provided with a group of wavy folds extending substantially opposite to the current, and at which projecting parts of the folds in a plate engage in the valley valleys delimited by the folds in the adjacent plate, characterized in that the wavy folds of the plates in a pair of plates are superimposed by another group of folds, which are formed by zigzagging folds in the flow direction, the zigzag formations of the plates being identical but oriented opposite in relation to an axis perpendicular to the plane of the plate on such salt, that the zigzag fold of one plate in a pair of plates repeatedly crosses the opposite zigzag folds of the other plate, and that the area of the channel section in all stalls along the length of the flow channel has constant size.

Heat exchanger according to claim 3, wherein the folding of the surfaces of a pair of plates in the direction of flow is repeated periodically, so that the geometric cross-sectional shape of the channel delimited by the plates, seen in the direction of flow, periodically changes its appearance. spruce shape to another, characterized in that the plates with folded ridges abut against each other in the stables (S) where the channel response section has one of its spruce shapes.

Heat exchanger according to claim 3, characterized in that the folds extending in the direction of flow of the two plates in a pair of plates have the same depth.

Heat exchanger according to any one of claims 3-5, characterized in that the water points of the zigzag lines to. The folds of the plates in the direction of flow alternately lie alternately on the ridges and ridges of the superimposed transverse folds of the plates. Request publications: Patents from Sweden 135,430, 137,587, 148,402; Germany. 826 445.