Patent Application
20120031595
The invention relates to the field of plates used in plate heat exchangers. Such plates are formed by means of a plate deformed by a press in order to produce a plurality of corrugations on its surface. These plates are then superimposed in order to make a bottom crest line of a first plate corresponding with the top crest lines of several corrugations located on a second plate arranged below the first.
The invention relates more particularly to an improvement of the plate allowing its fabrication with a particular arrangement and orientation of the corrugations on its surface.
In general, it is known to modify the form of the corrugations of a plate in order to limit the deformation of the plate during its fabrication. In fact, when a method is implemented to deform a plate in order to produce a plurality of corrugations on its surface, the said surface may be deformed in one or more directions. In this case, a plate is obtained whereof the active heat exchange zone does not have perpendicular adjacent sides.
To avoid these undesirable deformations or a local elongation of the plate, it is therefore known to add stiffeners which consist of a substantial reduction of the height of the top crest line or even a complete flattening of the corrugation. However, this type of stiffener is generally distributed for the whole surface of the plate in order to improve the stiffness of a plate in the direction perpendicular to the corrugations.
Thus, it is the object of the invention to provide an advantageous distribution of the stiffeners on the surface of the plate in order to improve the reinforcement of the plate in the direction perpendicular to the corrugations and to uniform the stiffness of a plate in both directions.
It is a further object of the invention to avoid locally disturbing the circulation of the fluid between the two plates despite the presence of stiffeners.
The invention therefore relates to a plate suitable for acting as a bulkhead between two fluids flowing in a plate heat exchanger. Such a plate comprises a plurality of corrugations each having a bottom crest line and a top crest line. All or part of the corrugations of the plate locally comprise stiffeners formed by a substantial or even total and local reduction of the height of the top crest line. The stiffeners are arranged in a first group of stiffeners distributed on the plate along at least one first line parallel to a diagonal of the plate, the diagonal being perpendicular to the crest lines of the corrugations. The stiffeners of the first group are alternately arranged on either side of the first line on each consecutive corrugation.
The invention is characterized in that the distance measured perpendicularly to the first line between the centre of the stiffeners of the first group and the first line is the same for each stiffener.
In other words, the stiffeners of the first group are distributed along the first line of the plate which perpendicular to the crest lines of the corrugations, serving to limit the elongation of the plate in a direction normal to the corrugations. On this first line, the stiffeners are also alternately positioned on each consecutive corrugation on one side or the other. Thus, the stiffeners are not distributed on the whole surface of the plate, but are located at least at one line of the plate which is parallel to one diagonal.
The constant distance between the centre of each stiffener of the first group and the first line serves to augment a stiffening effect and to concentrate it in one direction perpendicular to the crests lines of the corrugations.
Advantageously, this distance may be equal to a half-pitch of a corrugation. Indeed, the shortest the distance is, the highest the stiffening effect is.
In practice, the first line may be arranged on the diagonal of the plate which is perpendicular to the crest lines of the corrugations. Thus, the stiffeners of the first group are distributed on the plate along at least this diagonal and alternately positioned on each consecutive corrugation.
According to a particular embodiment, the stiffeners may also be arranged in a second group of stiffeners distributed on the plate along a second line parallel to the crest lines of the corrugations, the stiffeners of the second group being alternately arranged on either side of this second line on each consecutive corrugation, the distance measured perpendicularly to the second line between the centre of the stiffeners of the second group and the second line being the same for each stiffeners. The stiffeners distributed along the second line of the plate parallel to the crest lines of the corrugations serve to avoid locally disturbing the fluid flow between the two plates.
Advantageously, the second line may be arranged symmetrically about the first line by a 90 degrees rotation about the centre of the plate. In this way, the elongation of the plate in the direction normal to the corrugations is limited, while not disturbing the fluid circulation, and despite the presence of the stiffeners.
In practice, the stiffeners may have a zero height above the bottom crest line. In this way, stiffeners may be formed by a flat, straight strip or simply a crest line connecting two bottom crest lines of the plate in this case.
Furthermore, other groups of stiffeners may be used and distributed along lines which may be arranged parallel or perpendicular to the first and second lines comprising the first groups of stiffeners.
Thus, the plate may comprise at least one third group of stiffeners alternately arranged on either side of a third line parallel to the first line.
In consequence, such an embodiment serves to augment a stiffening of the plate in the direction normal to the corrugations, and on the whole surface of the plate.
Furthermore, the plate may comprise another third group of stiffeners arranged on either side of a fourth line and symmetrically about the third preceding group by a 90 degrees rotation about the centre of the plate.
Such a rotational symmetry may be effected in both rotation directions and serves to avoid locally disturbing fluid circulation between the two plates.
In practice, the distances between adjacent parallel lines of stiffeners may be the same for each line. Furthermore, the distance between two stiffeners on the same crest line is preferably constant and at least equal to one corrugation pitch. Thus, the stiffness of the plate is increased in a uniform manner in the direction perpendicular to the corrugations.
The manner of implementing the invention and the advantages thereof will clearly appear from the embodiment that follows, provided for information, but non-limiting, in conjunction with the figures in which:
As already stated, the invention relates to a plate acting as a bulkhead between two fluids flowing in a plate heat exchanger.
As shown in
According to the invention, these stiffeners 5 are arranged in a first group 20 distributed on the plate 1 along the first line 6 normal to the corrugations in order to limit the elongation of the plate in this direction during its fabrication. They may also be arranged in a second group 21 distributed along the second line 16 in order to avoid locally disturbing the fluid circulation between the two plates. According to this particular embodiment, the first line 6 is arranged on the diagonal 10 of the plate 1.
Other stiffeners may also be positioned on third line 8 parallel to the first line 6. Those stiffeners are arranged in this case according to a third group 7 of stiffeners on either side of the third line 8.
Furthermore, another third group 17 of stiffeners may be arranged along a fourth line 18 perpendicular to the first line 6 and to the second line 8, the stiffeners of this third group 17 also being arranged on either side of the fourth line 18. Thus, second group 17 is the symmetrical counterpart of the second group 7 by rotation about the centre 9 of the plate 1.
As shown, the plate 1 is formed by a grid of stiffeners 5 arranged in first group 20, second group 21 and third group 7, 17 distributed along a first and second lines 6, 16 and plurality of third and fourth lines 8, 18.
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According to another embodiment and as shown in
It appears from the above that a plate according to the invention has numerous advantages and in particular:
it serves to limit the elongation deformations during its fabrication;
it does not disturb the fluid circulation inside the heat exchanger.
| Number | Date | Country | Kind |
|---|---|---|---|
| 09305023.5 | Jan 2009 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP09/67815 | 12/22/2009 | WO | 00 | 9/22/2011 |
