Note: Descriptions are shown in the official language in which they were submitted.
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Plate heat exchanger
THE FIELD OF THE INVENTION
The present invention refers to a plate heat exchanger
comprising a plurality of heat exchanger plates. Such plate heat
exchangers may be used in various fields, for instance in the
combustion gas channel of combustion plants for gaining heat
energy from the combustion gases.
THE BACKGROUND OF THE INVENTION AND PRIOR ART
In plate heat exchangers of the kind mentioned above, which are
open outwardly to the surrounding edge side and which do not
have any downwardly bent flange along the edge of each heat
exchanger plate, it is difficult to guide the heat exchanger plates
in connection with the mounting of the plate package.
Consequently, it is difficult to provide a correct position for each
individual heat exchanger plate in relation to the other heat
exchanger plates when the plate package is mounted and during
the joining of the heat exchanger plates to each other, for
instance during a following brazing of the plate package. The
guiding and the positioning of the heat exchanger plates require
with the technique of today use of external guiding elements of
various kinds.
US-A-5,918,664 discloses a plate heat exchanger of the kind
initially defined, which comprises a plurality of heat exchanger
plates. Each of the heat exchanger plates extends in parallel
with a main extension plane. The heat exchanger plates are
provided beside each other so that they form a plate package
having an surrounding edge side and first plate interspaces for a
first medium and second plate interspaces for a second medium.
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Every second heat exchanger plate is formed by a first of said
heat exchanger plates and the remaining heat exchanger plates
are formed by a second heat exchanger plate in such a way that
such a first heat exchanger plate together with such a second
heat exchanger plate form a pair of heat exchanger plates,
which encloses such a first plate interspace, and that the plate
package comprises a plurality of such pairs of heat exchanger
plates. Each of the heat exchanger plates has at least two
portholes forming ports extending through the plate package and
communicating with the first plate interspaces. The heat
exchanger plates are configured in such a way that the second
plate interspaces are open through the surrounding edge side.
US-A-5,967,227 discloses a plate heat exchanger of another
kind comprising a plurality of heat exchanger plates which each
extends in parallel with a main extension plane. The heat
exchanger plates are provided beside each other in an
alternating order for forming a plate package. The heat
exchanger plates form first plate interspaces for a first medium
and second plate interspaces for a second medium. The first
and second plate interspaces are sealed by means of
surrounding gaskets. Each of the heat exchanger plates has two
portholes, which form ports extending through the plate package
and communicating with the first plate interspaces, and two
portholes, which form ports extending through the plate package
and communicating with the first plate interspaces. Each heat
exchanger plate comprises a bent part in each corner, which
cooperates with a corresponding bent part of the adjoining heat
exchanger plates in the plate package.
SUMMARY OF THE INVENTION
The object of the present invention is to overcome the problems
mentioned above and to facilitate the guiding and the positioning
of the heat exchanger plates in connection with the mounting
and the joining of the plate package.
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This object is achieved by a plate heat exchanger of the kind
initially defined, which is characterized in that each of the
portholes of such a first heat exchanger plate is configured in
such a way that it cooperates with an opposite porthole of such
a second heat exchanger plate in order to ensure that each pair
of heat exchanger plates takes a determined position in relation
to adjoining pairs of heat exchanger plates.
By means of two such bent parts cooperating with each other
when a first heat exchanger plate is laid against a second heat
exchanger plate, it may be ensured that the two heat exchanger
plates are guided to a correct position and that this position is
maintained during the whole mounting and joining of the plate
package and the plate heat exchanger. When the two heat
exchanger plates have been attached to each other, the two
bent parts may prevent them from being displaced or rotated in
relation to each other in a plane parallel to the extension plane.
Furthermore, a correct positioning of the different pairs in
relation to each other is facilitated thanks to the fact that the
portholes are designed to cooperate with a corresponding
porthole of an adjoining pair in the plate package. The portholes
will thus contribute to the guiding of the pairs of heat exchanger
plates to a determined position in relation to each other and to
the maintaining of this position of the pairs of heat exchanger
plates during the whole manufacturing process.
According an embodiment of the invention, each first and
second heat exchanger plate has a compression-moulded
pattern, which extends in a pressing direction with regard to the
extension plane, wherein the first bent part extends in a first
direction with regard to the extension plane of the first heat
exchanger plate and the second bent part extends in a second
direction with regard to the extension plate of the second heat
exchanger plate, and wherein the second direction extends in
the same direction as the pressing direction but is opposite to
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the first direction. Since the bent parts extend in different
directions in relation to the extension plane and in relation to the
heat exchanging pattern and port areas of the compression-
moulded plate, the bent parts are advantageously produced in a
shaping operation after the main compression-moulding of the
pattern and port areas of the plate. The first direction and the
second direction may then extend transversally or substantially
transversally to the extension plane. Furthermore, each second
heat exchanger plate may be rotated 1800 in relation to each
first heat exchanger plate in the finished plate package. In such
a way the first bent part and the second bent part will extend in
the same direction in the finished plate package, which makes it
possible to provide a proper form fitting and a proper form
locking between the first and second bent parts and thus
between the first and second heat exchanger plates in each
pair.
According to a further embodiment of the invention, each heat
exchanger plate extends along a longitudinal centre line, which
extends through the bent part. Furthermore, each second heat
exchanger plate in the plate package may be rotated 180
around the centre line of the heat exchanger plate.
According to a further embodiment of the invention, the first and
second heat exchanger plates are permanently joined to each
other in the plate package. Such a permanently joined plate
package may be achieved by means of brazing, gluing or
welding.
According to a further embodiment of the invention, each first
heat exchanger plate comprises two first bent parts and each
second heat exchanger plate two second bent parts. Two such
bent parts of each heat exchanger plate are sufficient for
ensuring the above mentioned positioning of the heat exchanger
plates in relation to each other.
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According to a further embodiment of the invention, the two first
bent parts are provided opposite to each other along a
respective edge of the first heat exchanger plate and the two
second bent parts are provided opposite to each other along a
5 respective edge of the second heat exchanger plate.
According to a further embodiment of the invention, each
portholes comprises a surrounding port area, wherein the port
area around a first porthole of each heat exchanger plate is
located at a first level with regard to the extension plane, and
the port area around a =second of said portholes of each heat
exchanger plate is located at another level with regard to the
extension plane. Advantageously, the port area around the first
porthole of a first pair of heat exchanger plates may be
configured in such a way that it is in engagement with the port
area around the second porthole of an adjoining second pair of
heat exchanger plates. The port area around the second
porthole of the first pair of heat exchanger plates may then be
configured in such a way that it is in engagement with the port
area around the first porthole of the adjoining second pair of
heat exchanger plates. In such a way, the portholes may
contribute to the guiding of the pairs of heat exchanger plates to
a determined position in relation to each other and to the
maintaining of this position of the pairs of heat exchangers
plates during the whole manufacturing process.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is now to be explained more closely through a
description of non-limiting embodiments and with reference to
the drawings attached.
Fig. 1 discloses an exploded perspective view of a plate
heat exchanger according to an embodiment of the
invention.
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Fig. 2 discloses a view from above of the plate heat
exchanger in Fig. I.
Fig. 3 discloses a section through the plate heat exchanger
along the line III-Ill in Fig. 2.
Fig. 4 discloses a section through the plate heat exchanger
along the line IV-IV in Fig. 2.
Fig. 5 discloses more closely a part of an edge area V of
the plate heat exchanger.
Fig. 6 discloses a simplified exploded perspective view of a
plate package of a plate heat exchanger according to
the invention.
DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS OF
THE INVENTION
With reference to Figs. 1-5 an embodiment of a plate heat
exchanger is disclosed. The plate heat exchanger comprises a
plurality of heat exchanger plates 1, 2. The heat exchanger
plates 1, 2 consists of first heat exchanger plates 1 and second
heat exchanger plates 2. All heat exchanger plates 1, 2 have a
heat exchanging function in the plate heat exchanger. Each heat
exchanger plate 1, 2 extends in parallel with a main extension
plane p, see Fig. 3. The extension plane p may be regarded as
extending through and in parallel with a basic plane of each heat
exchanger plate 1, 2, from which each plane heat exchanger
plate 1, 2 has been compression-moulded in a manner known
per se for achieving a compression-moulded pattern including a
heat exchanging pattern with corrugations and a port area
pattern.
The heat exchanger plates 1, 2 are provided beside each other
in such a way that they form a plate package 3 having an edge
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side 4, which extends around the plate package 3. The heat
exchanger plates 1, 2 form, in the plate package 3, first plate
interspaces 5 for a first medium and second plate interspaces 6
for a second medium, see Fig. 3. The heat exchanger plates 1, 2
are also provided in such a way in the plate package 3 that
every second heat exchanger plate is a first heat exchanger
plate 1 and the remaining heat exchanger plates are a second
heat exchanger plate 2. As can be seen especially from Figs. 1
and 3, a first heat exchanger plate 1 and an adjoining second
heat exchanger plate 2 form a pair of heat exchanger plates in
the plate package 3 in such a way that this pair of heat
exchanger plates encloses a first plate interspace 5. As can be
seen, the plate package 3 comprises in the embodiment
disclosed three such pairs of heat exchangers plates 1, 2. It is
to be noted here that the plate heat exchanger of course may
comprise fewer or more such pairs of heat exchanger plates 1, 2
depending on the specific application for the plate heat
exchanger.
In the embodiment disclosed, each heat exchanger plate 1, 2
has two portholes 8, 9, which form ports extending through the
plate package 3 and communicating with the first plate
interspaces 5. One of the portholes 8, 9 thus forms an inlet port
for the first medium to the first plate interspaces 5 whereas the
other porthole 9 forms an outlet port for the first medium from
the first plate interspace 5.
The heat exchanger plates 1, 2 are configured in such a way
that the second plate interspaces 6 are open through the
surrounding edge side 4. The second medium may thus flow
freely in through the edge side 4 of the plate heat exchanger
into the second plate interspaces 6 and out through the edge
side 4. Depending on how the plate heat exchanger is arranged
in relation to the flowing of the second medium, the flow
direction of the second medium through the plate heat
exchanger may be determined.
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Each porthole 8, 9 comprises a surrounding port area 10, 11.
The port area 10 around the first porthole 8 of each heat
exchanger plate 1, 2 is located at a first level p' with regard to
the extension plane p, and the second port area 11 around the
second porthole 9 of each heat exchanger plate 1, 2 is located
at a second level p" with regard to the extension plane p, see
Fig. 3. In the embodiment disclosed, both port areas 10, 11 are
located on the same side of the extension plane p wherein the
level p' is located more far away from the extension plane p than
the level p".
The plate heat exchanger also comprises a frame plate 13 and a
pressure plate 14, which do not have any heat exchanging
function. The pressure plate 14 has in the embodiments
disclosed no portholes whereas the frame plate 13 has portholes
being concentric to the portholes 8 and 9, respectively.
Connection pipes 15 and 16 are connected to the frame plate 13
for permitting communication with a respective one of the
above-mentioned ports.
Each first heat exchanger plate 1 comprises two first bent parts
21 and each second heat exchanger plate 2 comprises two
second bent parts 22. The first bent part 21 is arranged to
cooperate with the second bent part 22 of each such pair of heat
exchanger plates 1, 2 in order to ensure that the heat exchanger
plates 1 and 2 in each pair takes a determined position in
relation to each other and that this position is maintained during
the whole manufacturing process of the plate heat exchanger.
In the embodiment disclosed, the first bent parts 21 extend in a
first direction with regard to the extension plane p of the first
heat exchanger plate 1 and more precisely away from the
extension plane p. The second bent part 22 extends in a second
direction with regard to the extension plane p of the second heat
exchanger plate 2, i.e. away from the extension plane p. The
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second direction is opposite to the first direction with regard to
the extension plane p. In the embodiment disclosed in Figs. 1-5,
the first direction is opposite to the above-mentioned pressing
direction. The second bent part 22 thus extends in the same
direction, or substantially the same direction, as the
compression-moulded pattern and port areas 10, 11 of the heat
exchanger plates 1, 2. The first direction and the second
direction extend transversally or substantially transversally to
the extension plane p. All heat exchanger plates 1, 2 in the plate
package 3 are thus identical except with regard to the bent parts
21, 22 extending in opposite directions.
When the plate heat exchanger is mounted, every second heat
exchanger plate 2 is rotated 180 in relation to every first heat
exchanger plate 1. After this rotation of the second heat
exchanger plates 2, the first bent part 21 and the second bent
part 22 will thus extend in the same direction in the finished
plate package 3, see especially Fig. 5. Each heat exchanger
plate 1, 2 extends along a longitudinal centre line x which is
parallel with the extension plane p. The second heat exchanger
plates 2 are in the plate package rotated 180 around the
respective centre line x. Fig. 6 discloses schematically in a
simplified manner a plate package 3 having two pairs of heat
exchanger plates 1, 2, where the second heat exchanger plates
2 have been rotated 180 around the centre line x. The bent
parts 21, 22 thus extend in the same direction in the plate
package 3.
As can be seen from Figs. 1, 2 and 6, the first parts 21 of each
first heat exchanger plate 1 are provided opposite to each other
along a respective edge 23 of the first heat exchanger plate 1.
More precisely, each first bent part 21 is concentrically provided
with regard to the longitudinal centre line x in such a way that
the centre line x extends centrally through the first bent part 21.
In the same way, the second parts 22 of each second heat
exchanger plate 2 are provided opposite to each other along a
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respective edge of the second heat exchanger plate 2. More
precisely, each second bent part 22 is concentrically provided
with regard to the longitudinal centre line x in such a way that
the centre line x extends centrally through the second bent part
5 22.
Each heat exchanger plate has in the embodiment disclosed in
Figs. 1-5 two opposite short edges 23 and two opposite long
edges 24. As can be seen the first and second parts 21, 22 are
10 provided at the two short edges 23. It is of course possible, as
an alternative with two bent parts of each heat exchanger plate
or a supplement with four bent parts of each heat exchanger
plate, to provide bent parts along the long edges 24.
In the embodiment disclosed, each heat exchanger plate 1, 2
has an edge area 25 adjoining the short and long edges 23, 24
and extending around the compression-moulded pattern and
port areas 10, 11 of the heat exchanger plate 1, 2. The edge
area 25 is substantially plane and parallel with the extension
plane p. In the embodiment disclosed, the extension plane p
also lies in the edge area 25. As can be seen from Fig. 3, the
edge area 25 of the first heat exchanger plate 1 abuts, in each
pair of heat exchanger plates 1, 2, the edge area 25 of the
second heat exchanger plate 2.
The plate heat exchanger thus comprises the above-mentioned
pairs of heat exchanger plates 21, 22. These pairs are disposed
beside each other in the plate package. Each of the portholes 8,
9 of the first heat exchanger plate 1 of such a pair is thus
configured in such a way that it cooperates with an opposite
porthole 8, 9 of the second heat exchanger plate 2 of an
adjoining such pair in order to ensure that each pair of heat
exchanger plates 1, 2 takes a determined position in relation to
adjoining pairs of heat exchanger plates 1, 2. More specifically,
the port area 10 around the first porthole 8 of a first pair of heat
exchanger plates 1, 2 is configured in such a way that it is in
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engagement with the port area 11 around the second porthole 9
of an adjoining second pair of heat exchanger plates 1, 2. The
port area 11 around the second porthole 9 of the first pair is
then configured in such a way that it is in engagement with the
port area 10 around the first porthole 8 of the second pair.
Thanks to the guiding of the heat exchanger plates 1, 2
achieved by means of the bent parts 21, 22 and the port areas
10, 11, all parts of the plate package 3, i.e. at least all heat
exchanger plates 1, 2 and possibly also the frame plate 13, the
pressure plate 14 and the connection pipes 15, 16, may be
mounted and disposed in their final position with a suitable
braze material between the parts, whereafter the plate package
3 is disposed in an oven and brazed in a manner known per se.
It is also imaginable to braze in a first step two heat exchanger
plates 1, 2 to the above-mentioned pairs and in a second step
braze the pairs so formed. Other joining methods than brazing
may also be used, for instance welding or gluing.
According to another alternative embodiment, the bent parts 21
and 22 may extend in the same direction away from the
extension plane p. When the plate package 3 is mounted,
wherein every second heat exchanger plate is rotated 180 , the
bent parts 21, 22 of the heat exchanger plates 1, 2 in each pair
will extend in opposite directions towards each other. In order to
achieve a locking of the position, the bent parts 21, 22 may then
be displaced from the centre line x in such a way that they
adjoin the centre line x. This embodiments has the advantage
that all heat exchanger plates 1, 2 may be made completely
identical. Possibly the locking of the position may be improved if
there are bent parts along each edge 23, 24.
The invention is not limited to the embodiments disclosed but
may be varied and modified within the scope of the following
claims.
