Plate heat exchanger

Plate heat exchanger in the form of several heat exchanger plates (1) placed close to and sealed against each other and having pressed-out ridges (4) to form the heating surface of the relative plate in order to provide two different flow passages in the same plate heat exchanger. The plate heat exchanger according to the invention consists of identically like heat exchanger plates (1), the packing groove (9) of which has its bottom placed in the central plane of the plate (1). The heating surface of the relative plate is further divided into at least two area portions (5-8), the ridges (4) in one area portion (5) having an angle (.alpha..sub.1) relative to the symmetry axes (X and Y, respectively) of the plate lying in its plane, which is different from the angle (.beta..sub.1) formed by the ridges (4) in the other area portion (6) with the symmetry axes and that one or more of the other plates included in the heat exchanger are turned 180.degree. about one of said symmetry axes (x, Y) starting from the orientation of one plate in the plate heat exchanger.

BACKGROUND OF THE INVENTION 
This invention relates to a plate heat exchanger in the form of several 
heat exchanger plates placed closed to and sealed against each other, 
which are provided with pressedout ridges to form the heating surface of 
the relative plate. 
SUMMARY OF THE INVENTION 
It is intended by the invention to provide two different flow passages in 
the same plate heat exchanger, which passages can arbitrarily be selected 
for both the media flowing in the plate heat exchanger. 
Due to high manufacturing costs of pressing tools for heat exchanger plates 
and costs of storage of such plates it is neccessary for a manufacturer to 
restrict the plate assortment. However, at the same time it is desired to 
provide such a great number of variations or variants of plate channels as 
possible in a plate heat exchanger so that a heat exchanging task can be 
solved with the least possible heating surface which desideratum, however, 
is very difficult to satisfy due to the limited plate assortment. 
Thus, it is possible today to vary the plate channels in the same plate 
heat exchanger which, however, is done with different types of plates. 
It is possible by the present invention, such as it is apparent from the 
characterizing portions of the claims, to form two different flow passages 
using only one type of plate in the plate heat exchanger, the plates being 
turned in three different ways relative to one another.

In FIG. 1 a heat exchanger plate 1 in accordance with the invention is 
shown. The plate 1 is in conventional manner provided with openings or 
ports 2 and packing grooves 3 for edge packings and packings around two of 
the ports. The heat exchanger plate 1 is further provided with parallel, 
pressed-out ridges 4 forming the heating surface of the plate. It is 
understood that not all the ridges are drawn in the figure. The heating 
surface of the heat exchanger plate is divided into four area portions 
5-8, the ridges 4 in the area portion 5 intersecting the Y-axis of the 
plate at an angle .alpha..sub.1, in the area portion 6 the Y-axis at an 
angle .beta..sub.1, in the area portion 7 the Y-axis at an angle 
.alpha..sub.2 and in the area portion 8 the Y-axis at an angle 
.beta..sub.2. 
FIG. 2 shows a part section taken on line II--II in FIG. 1, three adjacent 
plates being drawn. The packing groove 9 has its bottom placed in the 
central plane of the heat exchanger plate 1, which is known per se. By 
this location of the packing groove 9 a plate can be turned 180.degree. in 
three different directions relative to an adjacent plate. Thus, the plate 
can be turned in its own plane, around its longitudinal axis (Y-axis) and 
its width axis (X-axis). The sealing surfaces of the packing grooves in 
adjacent plates will be equal in all three cases. 
The plate patterns around the packing grooves are not shown in the figures 
and it is to be understood that the corrugations in these areas are so 
formed that the required support points between adjacent plates are 
obtained at a mutual turning of these. 
In order to describe the formation of different plate channels it is 
referred to FIGS. 1, 3 and 4. Assuming that a similar plate is adapted 
close to a plate according to FIG. 1 and turned 180.degree. about its 
X-axis. The arrow angles of the pressed-out ridges in the heating surface 
will then point in a direction contrary to the turned plate as compared 
with the starting plate according to FIG. 1. If the plate, on the other 
hand, is turned about its Y-axis, the arrow angles will have the same 
direction as the arrow angles in the original plate according to FIG. 1. 
In order to simplify the description of the invention it is assumed that 
the angles .alpha..sub.1 =.alpha..sub.2 and .beta..sub.1 =.beta..sub.2 and 
only one of the four area portions of the heating surface is considered, 
because the ridges of two adjacent plates will intersect each other 
equally in all four portions of the heating surface. In FIG. 3 a plate is 
shown as turned about the X-axis, the ridges intersecting each other at an 
angle (.alpha.+.beta.). FIG. 4 shows the corresponding thing but with the 
plate turned 180.degree. about the Y-axis, the angle between the ridges of 
the plates being (180-.beta.+.alpha.). In the practical embodiment the 
angles .alpha. and .beta. should be selected with respect to the desired 
thermal length of the channel, the demand for a sufficient number of 
support points being considered. The angle between the intersecting ridges 
has a considerable influence on the flow properties of the plate channel. 
One skilled in the art will realize from the above that several combination 
possibilities are present by means of the invention to form flow passages 
in the finished plate heat exchanger so that e.g. one of the media passes 
merely in one type of flow channel and the other medium merely in the 
other type of flow channel, i.e. quite asymmetrical channels can be 
obtained for the two media. The plate assembly can also be arranged for 
each of the media so that one medium flows in both types of flow channels. 
The combination possibilities of the different flow channels are described 
more closely in the form of an example of a quite asymmetrical plate 
assembly according to FIG. 5. All the plates are identical here and 
correspond to the plate shown in FIG. 1, the plates however being 
designated by the numerals 11-16. It is assumed that the plate 11 has the 
same orientation as the plate shown in FIG. 1. The adjacent plate 12 has 
been turned about its Y-axis. The arrow angles of the ridges will point in 
the same direction between plate 11 and plate 12. A flow passage is formed 
between the plates 11 and 12 for one medium, the medium A. The plate 13 is 
the plate according to FIG. 1 turned 180.degree. in its own plane. A flow 
passage of the other medium, medium B, is then obtained, which passage has 
oppositely directed arrow angles. Plate 14 is a plate 1 turned 180.degree. 
about the X-axis and the arrow angles between plate 13 and plate 14 will 
point in the same direction. Plate 15 has the same orientation as plate 
11. The arrow angles of the ridges will be directed in opposite directions 
between plate 14 and plate 15. Plate 16 is turned 180.degree. about its 
Y-axis and the arrow angles of the ridges point in the same direction as 
at plate 15. The plates 11, 13 and 15 have their sides--heating 
surfaces--in the same direction and in the example as shown in FIG. 1. 
With respect to this side or heating surface the plates 12, 14 and 16 are 
turned in the other direction. 
As is well-known to one skilled in the art the media will flow via selected 
ports 2 in every other plate channel, e.g. the medium A will flow in the 
plate channels formed between the plates 11 and 12, the plates 13 and 14 
and the plates 15 and 16. The medium B will flow in the space between the 
plate 12 and 13 and the plates 14 and 15. The flow passages of the medium 
A have the arrow angles of the ridges in the same direction whereas the 
channels in which the medium B is flowing, have counterdirected arrow 
angles of the adjacent plates. Thus, FIG. 5 shows a plate heat exchanger 
where the medium A flows merely through one sort of flow passages and the 
medium B merely through another sort of flow passages. 
It is clearly realized by one skilled in the art from the above that it is 
possible by means of only one type of heat exchanger plate to build a 
plate heat exchanger capable of satisfying approximately the demands that 
may be required. 
The plate can of course be designed in several ways within the scope of the 
invention maintaining only one type of heat exchanger plate with the 
economical advantages brought by this. In FIG. 6 a plate having eight 
different area portions is shown. In the example shown the four upper area 
portions agree in principle with each other as well as the four lower area 
portions, being similar in principle the area portions of the plate 
according to FIG. 1. This means quite practically that the four upper 
portions are pressed in one step in the manufacture of the plate and in 
next step the four lower portions are pressed. 
The number of area portions and the size of arrow angles can of course be 
varied within the scope of the invention. It must however be presupposed 
that said area portions must not form mirror images about one of the 
symmetry axes lying in the plane of the plate.