US3783090A

US3783090A - Heat exchanger plates

Info

Publication number: US3783090A
Application number: US00226693A
Authority: US
Inventors: J Andersson; N Stadmark
Original assignee: Alfa Laval AB
Current assignee: Alfa Laval AB
Priority date: 1971-02-19
Filing date: 1972-02-16
Publication date: 1974-01-01
Anticipated expiration: 1991-01-01
Also published as: FR2125471B1; DE2207756C3; DE2207756B2; GB1357282A; IT947614B; JPS52271B1; DE2207756A1; SE353954B; FR2125471A1

Abstract

The heat exchanger plates include at least one plate having on one face of its heat transferring part a first group of ridges extending in parallel spaced relation to each other and pressed upward from the plane of the plate, this face also having a first group of grooves extending in parallel spaced relation to each other at an angle to the ridges and depressed from said plate; and the other face has second groups of ridges and grooves formed by the grooves and ridges, respectively, of the first groups. Each of these faces has its ridges substantially abutting an opposing plate so as to define therewith a set of channels between its ridges, each channel extending across a plurality of the grooves in such face. The two sets of channels provide a low resistance to flow of the respective heat exchanging media, while the ridges provide effective spacing means for preventing deformation of opposing plates under the pressure difference between such media.

Description

Jan. 1, 1974 A, ANDERSSQN ETAL 3,783,090

1 HEAT EXCHANGER PLATES Filed Feb. 16, 1972 I '7 Sheets-Sheet 1 Jan. 1, A ANDERSSON ETAL 3,783,090

HEAT EXCHANGER PLATES Filed Feb. 16. 1972 I '7 Sheets-Sheet 7 Jan. 1, 1974 J A. ANDERSSON Er AL HEAT EXCIIANGER PLATES 7 Sheets-Sheet 3 Filed Feb. 16, 197

Jan. 1, 1974 A, ANDERSSON E'TAL I 3,783,090

HEAT EXCHANGER PLATES I Filed Feb. 16. 1972 v SheetsSheet 4 Jan. 1, 1974 A ANDERSSON ETAL 3,783,090

HEAT EXCHANGER PLATES 7 Sheets-Sheet 5 Filed Feb. 16. 1972 Jan. 1, 1974 JAA. ANDERSSON ETAL 3,783,090

HEAT EXCHANGER PLATES Filed Feb. 16. 1972 7 Sheets-Sheet United States Patent rm. oi. Fzsr 3/00 US. Cl. 161-166 12 Claims ABSTRACT OF THE DISCLOSURE The heat exchanger plates include at least one plate having on one face of its heat transferring part a first group of ridges extending in parallel spaced relation to each other and pressed upward from the plane of the plate, this face also having a first group of grooves extending in parallel spaced relation to each other at an angle to the ridges and depressed from said plane; and the other face has second groups of ridges and grooves formed by the grooves and ridges, respectively, of the first groups. Each of these faces has its ridges substantially abutting an opposing plate so as to define therewith a set of channels between its ridges, each channel extending across a plurality of the grooves in such face. The two sets of channels provide a low resistance to flow of the respective heat exchanging media, while the ridges provide effective spacing means for preventing deformation of op posing plates under the pressure difference between such media.

The present invention relates to heat exchanger plates of the kind having spacing members in the form of protuberances and depressions in the heat exchanging surfaces. Such protuberances and depressions usually serve not only as spacing means but also to create, with reference to a desired heat transferring coefficient, a properly adapted disturbance of the flow of the heat exchanging media across the heat exchanging surfaces.

The present invention relates particularly to heat exchanger plates in which at least some of the spacing members on the heat exchanging surfaces will create only a small disturbance of the flow of the heat exchanging media. Spacing members of this kind are desirable, for instance, in the so-called distrbution surfaces for a heat exchanging medium. It is also desired sometimes to have spacing 'members of this kind over the entire heat exchanging surfaces, -as when the heat exchanging media are to be subjected to only a small pressure drop in their passage through the plate heat exchanger. However, ideal heat exchanger plates of this kind are difiicult to provide, because the greater the free area that is left for the flow of the heat exchanging media across the plates, the less strength the plates will have for resisting diiferences in pressure between the heat exchanging media.

The principal object of the present invention is to provide an arrangement of the spacing members on heat exchanger plates which meets the requirements as to good strength of the plates while imposing little resistance to the flow of the heat exchanging media.

According to the invention, the heat transferring part of a heat exchanger plate is provided on one face with spaced parallel ridges pressed up from a plane of the plate ice and with spaced parallel grooves, forming an angle with these ridges, depressed from the same plane of the plate. The other face of this heat transferring part has ridges and grooves formed by the grooves and ridges, respectively, on the first face; and each face has its ridges substantially abutting an opposing plate so as to define therewith a set of channels between its ridges, each channel extending across a plurality of the grooves in the same face. The two sets of channels serve for passage of the respective heat exchanging media with relatively small flow resistance. This low resistance is due to the fact that each channel has a wall which is bounded laterally by spaced ridges and which consists of a number of unobstructed parallelogram areas located one after the other in a row, each of which is surrounded along its four sides by the ridges and grooves pressed in difierent directions, where the so-called limit of stretching strain for the plate material has been increased by the cold-forming of the ridges and grooves.

By the present invention,'heat exchanger plates of a given material can be made as thin as possible for a given difference in pressure between two heat exchanging media, and for a given flow resistance for these media in the finished plate heat exchanger. This is of great importance from a material-saving point of view and also from a production point of view. Also, for the heat-transferring ability of the heat exchanger plates, it is important that they be as thin as possible.

The shape of the ridges and grooves may vary in different ways. Thus, either the ridges or the grooves may extend without interruptions along the whole or at least a great part of their respective lengths. Preferably, however, the ridges as well as the grooves have such interruptions. In a preferred embodiment, ridges and grooves which cross each other have interruptions at their common crossing points, the portions of the plate at their interruptions preferably being situated in the same plane as the afore-mentioned plane of the plate.

According to a alternative embodiment, the extensions of the grooves are interrupted by the ridges, the latter having interruptions in their extensions which are so placed that unbroken portions of the plane of the plate extend parallel to the grooves across these ridge interruptions.

It is not absolutely necessary that a plate having an arrangement of spacing members as described above be used together with plates of the same kind in a plate heat exchanger. However, the advantages of the described arrangement are believed to be utilized in the best way if plates of the same kind are used. The ridges and the grooves should then be so formed in each plate that when two plates are put together in a plate heat exchanger in a conventional manner, ridges on one plate will abut, along the whole or a part of their respective lengths, corresponding ridges parallel thereto on the other plate.

In the following, the invention is further described with reference to the accompanying drawings. In the drawings, FIG. 1 is a plan view of part of a heat exchanging surface of a plate according to the invention; FIGS. 2 and 3 are sectional views along the lines A-A and B-B, respectively, in FIG. 1; FIG. 4 shows a section through three cooperating plates according to FIG. 1; FIGS. 5-8 are views corresponding to FIGS. 1-4, respectively, but showing a second embodiment; FIGS. 9-12 are views corresponding to FIGS. 1-4, respectively, but showing a third embodiment; FIGS. 13 and 14 are sectional views 3 Y 7 showing different embodiments of the previously mentioned plane of the plate; FIG. is a plan view of a plate adapted for heat exchange according to the so-called cross flow principle; FIG. 16 is a plan view of a plate adapted for heat exchange according to the so-called parallel flow principle; FIG. 17 is a plan view of a plate of the kind shown in FIG. 16 and which has its so-called distribution surfaces provided with ridges and grooves according to the arrangement in FIG. 1; FIG. 18 is a perspective view of two cooperating plates according to FIG. 17; and FIGS. 19-21 are sectional views along the lines k-k, l[ and m-m, respectively, in FIG. 18.

The embodiment of the plate according to FIGS. 1-4 has spaced parallel ridges 1 pressed up from a plane 2 of the plate, and spaced parallel grooves 3 forming an angle (a) with these ridges, the grooves being depressed from the same plane 2 of the plate. As can be seen from FIG. 1, each ridge 1 is uninterrupted along its length, while the grooves 3 are interrupted along their respective lengths by the ridges 1. The pressed-up ridges 1 define between them upwardly opening trough-like channels 4 (FIG. 3), the bottoms of which are constituted by substantially the said plane 2 of the plate. The bottoms of the channels 4 are formed by several parallelogramshaped areas arranged in a row one after the other between the ridges 1. On the other face of the plate, a second group of ridges is formed by the depressed grooves 3, these ridges (like the grooves 3) having interruptions in their extensions; and a second group of grooves is formed by the ridges 1, these grooves (like the ridges 1) being uninterrupted along their respective lengths. Thus, channels 5 are formed on this face which have the said plane 2 of the plate as their bottom and which are similar to the first set of channels 4. The latter channels 5 extend between the ridges on this face of the plate, which are formed by the said grooves 3.

It will be apparent, therefore, that the plate has on one face a first set of parallel channels 4 and on the other face a second set of parallel channels 5 forming an angle (a) with the first channels. The channels 4 and S are intended for throughflow, in their respective longitudinal directions, of the two heat exchanging media separated by the plate.

Referring to FIG. 4, it shows how three heat exchanger plates A1, B1 and C1, conotructed according to FIG. 1, define flow passages in a plate heat exchanger. Each plate is turned 90 in its own plane relative to the adjacent plate. In the arrangement according to FIG. 4, this means that the uninterrupted upwardly-extending ridges 1 of the plates A1 and C1, which are turned in the same direction, extend parallel to each other and are aligned with each other vertically (i.e., in the plane of the drawing) while the uninterrupted upwardly-extending ridges 1 of the plate B1 extend perpendicular to the firstmentioned ridges. As can be seem from the drawing, the underneath side of the grooves 3 of the plate A1 extend parallel to and substantially abut the pressed-up ridges 1 of the plate B1; and correspondingly the underneath side of the grooves 3 of the plate B1 extend parallel to and substantially abut the pressed-up ridges 1 of the plate C1. Thus, each of the channels 5 of the plate A1 forms together with a respective channel 4 of the plate B1 a substantially closed channel 6 between the plates A1 and B1. Similarly, closed channels are formed between the plates B1 and C1 by the channels 5 of the plate B1 and the channels 4 of the plate C1, the latter closed channels extending at right angles to the channels 6.

The only difference between the embodiment of FIG. 5 and that according to FIG. 1 is that the pressed-up ridges 1 in FIG. 5, like the depressed grooves 3, have interruptions at certain intervals in their respective lengths. (These interruptions are not necessarily as regularly spaced as shown in this embodiment.) The interruptions in the extension of the ridges 1, which are designated 7, are situated at opposite sides of the parallelogram-shaped areas which form the bottoms of the channels 4 between the ridges 1. The parts of the plate situated at the interruptions 7 are in the same plane as the parallelogramshaped areas, so that unbroken parts of the said plane 2 of the plate extend parallel to the grooves 3 across these interruptions 7.

FIG. 8 is a sectional view corresponding to that in FIG. 4 but showing three plates A2, B2 and C2. according to FIG. 5.

The difference between the embodiment of FIG. 9 and that shown in FIG. 5 is that the interruptions in the extensions of the pressed-up ridges 1 in FIG. 9 are situated where these ridges would otherwise cross the grooves 3 instead of between these grooves. Such interruptions in FIG. 9 are designated 8. Also in this embodiment the parts of the plate situated at the interruptions 8 are in the same plane as the parallelogram-shaped areas between the ridges 1 and the grooves 3, i.e., in the previously mentioned plane 2 of the plate, as can be seen from FIGS. 10-12.

FIG. 12 is a sectional view corresponding to those in FIGS. 4 and 8 but showing three plates A3, B3 and C3 according to FIG. 9.

In all of the above-described embodiments of the plate according to the invention, the parallelogram-shaped areas between the ridges 1 and the grooves 3 are entirely planar. This is not essential. As shown in FIGS. 13 and 14, these areas may be stifiened by being bent in one or the other direction or provided with a generally corrugated shape in section. Further, these parts of the plate (as will be evident from the following) need not be centered exactly between the crests of the ridges 1 and the underneath sides of the grooves 3. By forming and placing the parallelogram-shaped areas of the plate differently, it is possible to change the flow conditions for the heat exchanging media flowing across the plate.

FIGS. 15 and 16 show two kinds of heat exchanger plates, which can utilize any of the arrangements according to FIGS. l-l4. The plate of FIG. 15 is a so-called cross flow plate, in which case a first heat exchanging medium flows across the plate on one side of it (the upper side as shown) from an inlet 9 to an outlet 10, while a second heat exchanging medium flows on the other side of the plate (crossing the flow direction of the first medium) from an inlet 11 to an outlet 12, the plate being gasketed in the usual manner as indicated at 17. The ridges 1 and grooves 3 are illustrated in FIG. 15 by dashed lines. In a pack of plates of this kind, every second plate is turned in its own plane relative to the other plates, so that the ridges of one plate will extend parallel with and abut the underneath side of the grooves of the adjacent plate. It is also possible that every second plate be turned about an axis extending in the plane of the plate.

The heat exchanger plate of FIG. 16 is adapted for substantially concurrent or counter-current flow of the two heat exchange media. The heat transferring area of this plate is divided into three areas F, G, and H, which have different kinds of turbulence effecting protuberances and depressions. The plate also has an inlet 13 and an outlet 14 for a first heat exchanging medium which flows on one side of the plate (its upper side as shown) and an inlet 15 and an outlet 16 for a second heat exchanging medium which flows on the opposite side of the plate (countercurrent flow heat exchange). For defining flow passages between adjacent plates in a plate heat exchanger, each plate has a strip seal or gasket 17. The flow of the said first heat exchanging medium from the inlet 13 to the outlet 14 is illustrated by arrows 18.

The purpose of the above-mentioned division of the heat transferring surface of the plate into areas having difierent designs of the turbulence effecting members is to distribute the heat exchanging media in the best way over the entire width of the heat transferring surfaces on their way from their respective inlets to their respective outlets. For this purpose, the so-called distribution surfaces F and H are provided with turbulence-effecting members so formed that the flow resistance for the medium entering through the inlet 13 or the inlet 15 is substantially less in these distribution surfaces than in the central part G of the plate, the latter part constituting the main heat exchanging surface of the plate. This reduces the effects arising from the fact that certain portions of the heat exchanging media must flow a longer way than other portions across the distribution surfaces. The previously described arrangement of the pressed-up ridges 1 and depressed grooves 3 is particularly useful, in heat exchanger plates of this kind, for the so-called distribution surfaces F and H.

FIG. 17 shows a heat exchanger plate P1 of the same kind as in FIG. 16, the distribution surfaces F and H being provided with pressed-up ridges 1 (full lines) and depressed grooves 3 (dashed lines). The squares formed on the plate by these ridges and grooves constitute the previously mentioned parallelogram-shaped areas. One of the ridges in the distribution surface F is designated 19, and one of the ridges in the distribution surface H is designated 20. In the distribution surface F, in the area between the ridge 19 and the opening 16, the plane 2 of the plate (i.e., the plane of the parallelogram-shaped areas) has been displaced a distance a perpendicular to the plane of the plate, so that the pressed-up ridges have a height over the plane 2 of the plate which exceeds by 2a the distance between the plane 2 of the plate and the underneath sides of the depressed grooves 3. Over the rest of the distribu tion surface F, the plane 2 of the plate is centered between the crests of the ridges and the underneath sides of the grooves. In the distribution surface H, the plane 2 of the plate is displaced the same way in the area between the ridge 20 and the opening 15.

When superimposing one heat exchanger plate on another, as when assembling them in a plate heat exchanger (i.e., with one plate turned 180 in its own plane relative to the other) two distribution surfaces F and H will c0- operate in different manners in diiferent parts of the same. FIG. 18 shows the plate P1 of FIG. 17 and a plate P2 of the same kind which is turned in the aforesaid manner. When the plates P1 and P2 are put together, the ridge 19 of the plate P1 will cross the ridge 20 of the plate P2 in the way that can be seen from FIG. 18. As a result, four different areas K, L, M and N are defined within the two cooperating distribution surfaces F and H.

FIGS. 19-21 show sections through the two cooperating plates P1 and P2 along the lines kk in the area K, l-l in the area L and mm in the area, M, respectively, in FIG. 18. The two plates P1 and P2 are assumed to have in their distribution surfaces an arrangement of ridges and grooves of the kind shown in FIG. 1. Thus, if the thickness of the plates P1 and P2 (i.e., the distance between the plane of the crests of the ridges 1 and the plane of the underneath sides of the grooves 3) is designated S, the depth of the interspace between the plates, i.e., the height of the channels 6 (see FIGS. 4, 8, 12), due to the previously mentioned displacement a of the plane 2 of the plate in certain parts of the distribution surfaces F and H, will be S a in the area K, S in the area L, and S a in the area M. In the area N, the plane 2 of each plate is centered between the two said planes for the crests of the ridges and the underneath sides of the grooves, and therefore the depth of the plate interspace here will be S. (For the sake of simplicity, no consideration has been paid to the plate material thickness in the above-made calculations of the plate interspace depth.)

Thus, for liquid flowing in the interspace between the plates P1 and P2 in FIG. 18 from the inlet 13 to the heat exchanging surfaces G of the plates, a greater flow resistance will arise in the area K of the distribution surfaces (see FIG. 19) than in the areas L (FIG. 20) and M (FIG. 21).

By suitable forming of the distribution surfaces F and H, it is thus possible to obtain a desired distribution of liquid entering through the inlet 13 (or the inlet 15) over the entire width of the plates P1 and P2.

We claim:

1. In a plate heat exchanger, a series of heat exchanger plates disposed in opposing face-to-face relation, at least one of said plates including a heat transferring part having on one face a first group of ridges extending in parallel spaced relation to each other and pressed upward from a plane of the plate, said one face also having a first group of grooves extending in parallel spaced relation to each other at an angle to said ridges and depressed from said plane, the other face of said heat transferring part having second groups of ridges and grooves formed respectively by the grooves and ridges of said first groups, the ridges of said first group substantially abutting a first opposing plate of said series and defining therewith, and with said one plate at its region-s between said first ridges, a first set of channels for a first heat exchanging medium, each said channel extending across a plurality of grooves of said first group, the ridges of said second group sub stantially abutting a second opposing plate of said series and defining therewith, and with said one plate at its regions between said second ridges, a second set of channels for a second heat exchanging medium and extending at said angle to said first channels, each channel of said second set extending across a plurality of grooves of said second group.

2. Heat exchanger plates according to claim 1, in which the ridges of said first group have at least one interruption in their respective lengths.

3. Heat exchanger plates according to claim 1, in which both the ridges and the grooves of said first groups have at least one interruption in their respective lengths.

4. Heat exchanger plates according to claim 3, in which each said interruption is located at the point where a ridge of said first group crosses a groove of said first group.

5. Heat exchanger plates according to claim 3, in which the parts of the plate where said interruptions occur are in said plane of the plate.

6. Heat exchanger plates according to claim 3, in which said interruptions of the grooves are effected by the ridges of said first group, said ridge interruptions occurring at parts of the plate lying in said plane and located between said interruptions of adjacent grooves.

7. Heat exchanger plates according to claim 1, in which said ridges and grooves are straight.

8. Heat exchanger plates according to claim 1, in which said angle is 9. Heat exchanger plates according to claim 1, in which said first opposing plate has ridges and grooves as in said one plate and is oriented with its ridges on one face parallel to and substantially abutting, along at least part of their respective lengths, opposing ridges of said first group on said one plate, whereby each channel of said first set also extends across a plurality of grooves in said one face of said first opposing plate.

10. Heat exchanger plates according to claim 9, in which said second opposing plate has ridges and grooves as in said one plate and is oriented with its ridges on one face parallel to and substantially abutting, along at least part of their respective lengths, opposing ridges of said second group on said one plate, whereby each channel of said second set also crosses a plurality of grooves in said one face of said second opposing plate.

11. Heat exchanger plates according to claim 1, in which said one plate has a pair of openings spaced from each other along one edge of the plate for admission of said first medium to and discharge from, respectively, the interspace between said one plate and said first opposing plate, said heat transferring part being located between said admission opening and an edge of said one plate opposite its said one edge and having its ridges of said first group extending substantially in the direction from said admission hole toward said opposite edge, said one plate having a second heat transferring part located between said discharge opening and said opposite edge, said second part having ridges and grooves as in said first part and with the ridges of its first group substantially abutting said first opposing plate but extending substantially in the direction from said opposite edge toward said discharge opening, said first group of ridges of the respective heat transferring parts slanting toward each other while extending in their respective said directions.

12. Heat exchanger plates according to claim 11, in

8 transferring parts have different depths along at least portions of their respective lengths, said first set of channels near said one edge being shallower than those more remote from said one edge.

References Cited UNIT ED'STATES PATENTS 3,151,675 10/1964 Lysholm 165-166 which the channels of said first set at each of said heat 10 CHARLES SUKALO, Primary Examiner