Note: Descriptions are shown in the official language in which they were submitted.
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The present invention is related to a heat exchanger
formed of a stack of plates.
Among known conventional plate-type heat exchangers
there is a typical one in which sealing rings are applied around
distribution openings through the plates alternatingly connecting
intermediate spaces formed between pairs of plates assembled in
a stack. When for example, plates of rectangular shape are used,
the distribution openings to and from the respective spaces are
located in opposite corners so that the fluid will flow diagonally
through the space~ The surfaces of the plates are usually
provided with a corrugation or the like in order to increase
the heat exchange or to reinforce the plates against the
pressures from the fluids.
According to the present invention there is provided
a heat exchanger comprising a stack of heat conducting plates,
wherein each plate is provided with generally a spiral-deforma-
tion defining crests and troughs, the troughs on one side of
the plate corresponding to the crests on the other side of the
plate, and wherein the plates are stacked such that the crests
on adjacent plates abut to divide the space between the plates
into a generally spiral channel, the ends of which communicate
with connecting channels arranged perpendicular to the planes
of the plates, the channels on opposite sides of each plate
being connected for flow of different fluids between which heat
is to be exchanged.
The invention will now be described further, by way
of example, with reference to the accompanying drawings, in which
Fig. 1 is a plan view of a plate of hea~exchanger of
the invention,
Fig. 2 is an exploded view of a plurality of stacked
plates
Fig. 3 shows a cross section along the line A-A in
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Fig. 1 of two plates located one above the other,
Fig. 4 shows across section perpendicular to the
section A-A,
Fig. 4a shows across section along the line B-B in
Fig. 3 and positioned perpendicularly to the line A-A,
Fig. 4b shows the same section as Fig. 4a but the plates
arranged in another relative angular position,
Fig. 4c shows the same section of Fig. 4a but the
plates arranged in still another relative angular position,
Fig. 5 shows a section B-B of a plurality of plates
located adjacent each other and arranged of several angular
positions with respect to one another.
The heat exchanger described in the following has
as principal parts plates according to Fig. 1 manufactured of
a heat conducting, neutral material, e.g. stainless steel sheet.
The plates are pressed and stamped into the shape shown in
the figures, i.e. a plurality of concentric deformations 1
constitute crests 2 and troughs 3 in the surfaces of the sheet
which is plane between the deformations and forms a plurality
of concentrically located flow channels between the deformations.
The channels are joined into a generally spiral path, the flow
being changed from an outer to an inner route, or vice versa,
through openings 4 and deflecting ridges 5 joining two adjacent,
concentric deformations. The plates have two central holes 6,7
and another two holes 8,9 at the peripheries. Two of these
holes 6 and 8, are the start and end, respectively, of the spiral-
shaped channel on one side of the plate, and the other two holes,
7 and9, are the start and end, respectively of the channel on
the other side of the plate. In Fig~ 1 the channel on the top
side is shown by continuous arrows and the one on the under side
by dashed arrows.
Besides the openings 4 in the deformations there are
notches or recesses 10 therein. The purpose of these is to
provide by-pass passages between adjoining channels. When the
plates are stacked upon each other, so that the notches in two
adjacent plates meet one another, such an overflow passage ll
created. The area of the passage 11 can be adjusted by angular
displacement of one plate relative to the other. The passage
11 can in this way be completely stopped, because the notch in
the one plate can be covered by the projection on the other.
In Fig. 4a there is shown a tangential section present-
ing two overflow passages ll having maximum area. In Fig. 4b asimilar section is shown, of the case where the lower plate is
rotated through an angle equal to the distance between the two
notches lOa, lOb. Hence, two of the notches, one in each
plate, are covered, but the other two are aligned to create a
by-pass passage ll. In Fig. 4c the lower plate is rotated through
an angle equal to half the distance between the notches lO, which
results in covering all the notches. A lot of design variants are
possible, e g. unequal numbers of notches on opposite sides of
the plate, different areas of notches and so on. A portion
of a stack in which the said type of displacements is employed
is shown in Fig 5 in which the section B-B thus is extended to
a plurality of plates in the stack. It may be appropriate for
example, in the case of hot water heat exchanger, to provide
one or more extra connecting channels 12 disposed at the input
or output of primary return water from a radiator heat exchanger
or the like. These extra channels will then divide the plates
into a pre-heating unit and a post-heating unit.
The plates can in a usual way be provided with ribs 13
in the flow channels which reinforce the plates so that unequal
pressures can be applied on the respective sides of the plate.
Around the peripheries and the connecting channels the plates are
sealed with respect to each other by means of sealing rings 14.
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This shown and described embodiment o~ the heat
exchanger is only an example of how the invention can be realized.
Besides the mentioned combinations there are, of course, others,
where one fluid has zero, one or two by-pass passages in each
section B-B and the other has two, one or none. Instead of
addition of fluid into the extra channels 12 it is also possible
to tap the fluid by such channels.
An advantage of the preferred embodiment of the
invention resides in that it is possible by altering the effective
length for the different fluids to optimize the quantity of
exchanged heat for a given available pressure drop.
