PLATE HEAT EXCHANGER

Abstract: Plate heat exchanger comprising heat exchange plates mounted between a frame plate and a pressure plate in a frame, the heat exchange plates between themselves forming channels for heat exchange media which are introduced into and taken out of the channels via ports in the corner portions of the plates, and each heat exchange plate having two distributing areas and an intermediate heating area and a plate pattern of turbulence generating and distance giving means, pressed out of the plate. According to the invention the two ports (8, 9) delimiting the inlet to each channel at least for one of the media are so designed in the two adjacent plates delimiting the mentioned channel that the one port (8) is positioned in the bottom plane of the one plate and the other port (9) is positioned in the top plane of the other plate.

Description: Plate heat exchanger This invention relates to a plate heat exchanger comprising heat exchange plates mounted between a frame plate and a pressure plate in a frame, the heat exchange plates between themselves forming channels for heat exchange media which are introduced into and taken out of the channels via ports in the corner portions of the plates, and each heat exchange plate having two distributing areas and an intermediate heating area and a plate pattern of turbulence generating and distance-giving means, pressed out of the plate. Such a heat exchanger is common today for heat exchange between two media of different temperatures. However, there is a need in the market for a plate heat exchanger, which is preferably intended for a high-viscous medium and/or a medium mixed with fibers. In order to manage a heat exchange where at least one of the media is high-viscous and/or mixed with fibers, the channels of the heat exchanger have to be designed in a special way. Thus, particularly the inlet of the channels at the plate ports must have such a design that a free inflow of the medium into the channel is allowed. Plates in known plate heat exchangers, in a known way, have a plate pattern comprising turbulence generating and distance giving means also at the area of the ports. In this connectio the plate has been so designed at the ports that when these ones have been cut out of the plate through the turbulence generating and distance giving means, the inlet of each channel, when two plates have been put together, has been comp ' osed of a number of cell-like openings. These cell-like openings have formed sharp edges for the inflowing medium, the consequence of which should be that, if a medium containing fibers is used, these fibers should fasten in the cell walls and shut off the inlet of the channels. Moreover, the cell-like openings into the channel would be too narrow for a high-viscous medium. The object of this invention is to design the plates forming the channelβ in that way that the media can stream relatively freely through respective channels. The object is achieved in a plate heat exchanger of the kind mentioned by way of introduc¬ tion, which is characterized in that the two ports delimiting the inlet to each channel at least for one of the media are so designed in the two adjacent plates delimiting the mentioned channel that the one port is positioned in the bottom plane of the one plate and the other port is positioned in the top plane of the other plate. A preferred embodiment of the invention usable for heat exchange of media of which one is high-viscous shall be described more closely in connection with the accompanying drawings, in which Fig. 1 shows a heat exchange plate according to the invention, Fig. 2 shows a section along the line II-II in Fig. 1 with the presumption that several plates are placed under that plate and Fig. 3 shows a section along the line III-III in Fig. 1 with the presumption that several plates are placed under that plate. The plate 1 in Fig. 1 is in a known way provided with four ports 2a-d for the media that shall be heat exchanged. Furthermore, the plate is provided with two distributing areas 3, 4 and a heating area 5. This heating area 5 is provided with particular distance means in the form of several ridges 6a-d which are parallel in relation to each other and symmetrically placed in relation to the longitudinal center line of the plate and extend in the longitudinal direction of the plate along essentially the whole heating area. Since this distance means has a height exceeding the height of the distance means in the ordinary plate pattern, there is formed, when putting this plate and a conven¬ tional one without the particular distance means together, on the former one's upper side a channel having a sufficient width for a high-viscous medium and/or a medium mixed with fibers. The ridges 6a-d are preferably positioned on only one side of the plate 1 and can be composed of folds which have been pressed out of the plate material. Instead of being an integral part of the plate, the ridges can be composed of loose parts which are welded or soldered to the plate. In the distributing surfaces 3, 4 the press pattern is so designed that a part of the distance means is given a height corresponding to the height of the distance means 6a-d. Further¬ more, at least a part of the distance means 7 in the inlet portions and outlet portions of the channels, i.e. in the area close to the plate ports, has also a height corresponding to the height of the distance means 6a-d. Due to that fact the distance between the plates can be guaranteed also in the passage of the distributing surfaces and at the area close to the plate ports. As has been previously mentioned the plates in previously known plate heat exchangers have been so designed at the area of the ports that the inlet of the channels has been composed of a cell pattern with sharp edges. There have been at least two drawbacks connected therewith. Firstly, these sharp edges results in that a medium containing fibers easily closes up the inlet of the channels. Secondly, these cells bring about a very limited inlet area, wherefore a high-viscous medium should meet a great resistance when flowing into the channels via these cells. These problems are solved according to the invention, the inlet getting the greatest possible width. This is brought about, as appears from Fig. 3, by giving the plates a special design at the area of the ports. Thus, the port of one of the plates (8 shows the inner edge of the port), in this case the plate provided with the particular distance ridges, is placed in the bottom plane of the plate, ^ while the port of the adjacent plate (9 shows the inner edge of the port) is placed in its top plane. Due to that fact the distance between the ports of the two plates, during co-operation of the distance means 7, 10 of the two plates, will be as great as possible. This has the conse¬ quence that the inlet to the channel for the viscous medium becomes as great as possible, whereby the inflow into the channel is facilitated. In Fig. 3 the viscous medium has been indicated by two arrows 11, 12. The mentioned placing of the ports in the two plates delimiting a channel for the viscous medium results in that the plates 9, 8 rest against each other at the port area between two inlets to the channels for the viscous medium. As has been shown in Fig. 3 the distance means 7, 10 are placed a short distance from the port edge 8, 9. This fact and the placing of the ports in bottom plane and top plane, respectively, have the consequence that there is formed a soft transfer passage without sharp edges for the viscous medium from the port channel and into the channel between the plates 8, 9. Due to that fact the inflow of the viscous medium into the channel is still more facilitated. Furthermore, from Fig. 3 is apparent that the distance means 7 of the press pattern of the one plate rests against the distance means 10 of the press pattern of the other plate, whereby the distance means form contact points between the plates In the area close to the plate ports. The invention is, of course, not limited to the mentioned embo¬ diment. Thus, it is possible to have two high-viscous media of essentially the same viscosity which shall be heat exchanged. In this case the inlets to the channels for both media shall be as wide as possible. This means, besides the fact that the port of the one plate shall be placed in its bottom plane and the port of the adjacent plate in its top plane, that the distance means of the press pattern of the plates being opposite to each other shall have essentially the same height. The distance means 6 can also be unsymmetrically placed in relation to the longitudinal center line of the plate, whereby the plate becomes mixable with itself. A heat exchanger built up by such plates should be particularly suitable to use when the two media are high-viscous. ,_• The special design of the plates at the area of the ports makes the heat exchanger particularly suitable to be used for media which are contaminated in different ways, for instance by fibers.

Claims: Claims 1. A plate heat exchanger comprising heat exchange plates mounted between a frame plate and a pressure plate in a frame, the heat exchange plates between themselves forming channels for heat exchange media which are introduced into and taken out of the channels via ports in the corner portions of the plates, and each heat exchange plate having two distributing areas and an intermediate heating area and a plate pattern of turbulence generating and distance giving means, pressed out of the plate, c h a r a c t e r i z e d I n that the two ports (8, 9) delimiting the inlet to each channel at least for one of the media are so designed in the two adjacent plates delimiting the mentioned channel that the one port (8) is positioned in the bottom plane of the one plate and the other port (9) is posi¬ tioned in the top plane of the other plate. 2. A plate heat exchanger according to claim 1, c h a r a c ¬ t e r i z e d i n that at least the one plate (1) in a channel has distance means (6a-d) comprising ridges extending in the longitudinal direction of the plate along essentially the whole length of the heating area, and that the distance means (6a-d) is pressed out of the plate material. 3. A plate heat exchanger according to claim 1, c h a r a c ¬ t e r i z e d i n that at least the one plate (1) in a channel has distance means (6a-d) comprising ridges extending in the longitudinal direction of the plate along essentially the whole length of the heating area, and that the distance means is composed of loose parts welded or soldered to the plate. 4. A plate heat exchanger according to claim 2 or 3, c h a r a c t e r i z e d i n that a part of the ridges in the distributing areas (3, 4) has a height corresponding to the height of the distance means (6a-d). 5. A plate heat exchanger according to any one of the claims 2-4, c h a r a c t e r i z e d i n that the press pattern in the area close to the plate ports has distance means (7) with a height corresponding to the height of the distance means in the heating area. 6. A plate heat exchanger according to any one of the claims 2-5, c h a r a c t e r i z e d i n that the distance means (6a-d; 7) has a height exceeding the height of the distance means (10) in the ordinary plate pattern. 7. A plate heat exchanger according to claim 2 or 3, c h a r a c t e r i z e d i n that the distance means (6a-d) in the heating area is symmetrically placed in relation to the longitudinal center line of the plate. 8. A plate heat exchanger according to claim 2 or 3, c h a r a c t e r i z e d i n that the distance means (6a-d) in the heating surface is unsymmetrically placed in relation to the longitudinal center line of the plate. 9. A plate heat exchanger according to claim 6, c h a r a c ¬ t e r i z e d i n that the distance means (7, 10) closest to the port area in the two plates forming a channel for a viscous medium is placed a distance from the port edge (8, 9), whereby a soft transfer passage is formed for the medium from the port channel and into the channel between the plates.

Inventors: ANDERSSON JARL, BERGQVIST JAN-OVE, ANDERSSON, JARL, BERGQVIST, JAN-OVE
Applicants: ALFA LAVAL THERMAL, ALFA-LAVAL THERMAL AB
Application year: 1986
Main classification: F28F3
IPC codes: F28F3