U.S. patent application number 09/904467 was filed with the patent office on 2002-01-17 for plate heat exchanger.
Invention is credited to Brenner, Albrecht, Podhorsky, Miroslav, Wittig, Horst.
Application Number | 20020005280 09/904467 |
Document ID | / |
Family ID | 7648960 |
Filed Date | 2002-01-17 |
United States Patent
Application |
20020005280 |
Kind Code |
A1 |
Wittig, Horst ; et
al. |
January 17, 2002 |
Plate heat exchanger
Abstract
A plate heat exchanger consists of a plate stack through which
pass heat-exchanging media preferably in a counterflow pattern. Its
individual plates (8) are provided with embossments (9) by means of
which consecutive plates (8) directly support one another. To
obtain a plate heat exchanger suitable for counterflow operation
while offering high compressive load resistance relative to both
media and permitting cost-effective production in terms of material
and labor, the plates (8) are provided with rows of trough-shaped
sectional embossments (9). On all plates (8) these sectional
embossments (9) are located on the same side, their rows extending
parallel to and at a uniform distance (.tau.) from one another.
Also, the rows of successively stacked plates (8) are situated
above one another.
Inventors: |
Wittig, Horst; (Ratingen,
DE) ; Podhorsky, Miroslav; (Ratingen, DE) ;
Brenner, Albrecht; (Ratingen, DE) |
Correspondence
Address: |
CANTOR COLBURN, LLP
55 GRIFFIN ROAD SOUTH
BLOOMFIELD
CT
06002
|
Family ID: |
7648960 |
Appl. No.: |
09/904467 |
Filed: |
July 13, 2001 |
Current U.S.
Class: |
165/166 |
Current CPC
Class: |
F28F 2250/104 20130101;
F28D 9/0037 20130101; F28F 3/042 20130101 |
Class at
Publication: |
165/166 |
International
Class: |
F28F 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 14, 2000 |
DE |
100 34 343.0-16 |
Claims
1. Plate heat exchanger consisting of a plate stack through which
pass heat-exchanging media preferably in a counterflow pattern and
whose individual plates (8) are provided with embossments which
serve as direct supports for consecutively superpositioned plates
(8), characterized in that The plates are provided with rows of
trough-shaped sectional embossments (9) which are located on the
same side of all plates (8), which rows extend parallel to and at a
uniform distance (.tau.) from one another, and that the rows of
consecutive plates (8) are positioned one above the other.
2. Plate heat exchanger as in claim 1, characterized in that the
sectional embossments (9) of neighboring plates (8) are mutually
offset in the direction of the rows.
3. Plate heat exchanger as in claim 2, characterized in that the
offset (V.sub.P) corresponds to half the length of the sectional
embossment (9).
4. Plate heat exchanger as in claim 2 or claim 3, characterized in
that the sectional embossments (9) of neighboring rows of a plate
(8) are mutually offset in the direction of the row.
5. Plate heat exchanger as in claim 4, characterized in that the
offset (V) corresponds to half the length of the sectional
embossment (9).
6. Plate heat exchanger as in one of the preceding claims,
characterized in that the plates (8) of the plate stack are
rectangular in design, that the intake and, respectively, the
discharge of the first heat-exchanging medium takes place at the
two short sides (6) of the plates (8) while the intake of the
second heat-exchanging medium takes place at one end, the discharge
at the other end of the long sides (7a and 7b, respectively) of the
plates (8).
7. Plate heat exchanger as in claim 6, characterized in that the
rows composed of the sectional embossments (9) extend parallel to
the short sides (6) of the plates (8).
Description
[0001] This invention relates to a plate heat exchanger including a
plate stack through which the heat-exchanging media preferably pass
in a mutual counterflow pattern and whose individual plates are
provided with embossments, with neighboring plates directly
supporting one another.
[0002] EP 0 658 735 B1 describes a plate-type crossflow heat
exchanger whose individual plates are paired up in a manner that
the plates of a pair face each other in mirror-image fashion. An
undulating channel extending between the individual plates of a
plate pair constitutes the path for one of the two heat exchanging
media. The other medium travels in the crossflow direction through
tubular-profile channels between the individual plates separating
neigboring plate pairs.
[0003] To produce the undulating flow pattern for the first medium
and the straight tubular flow pattern for the other medium the
plates are provided with several parallel rows of sectional
trough-shaped embossments extending in the flow direction of the
second medium. The sectional embossments of neighboring rows in the
plate are mutually offset in the longitudinal direction, creating
between adjoining plates flat-surfaced supports in the form of
essentially rhomboid support zones which are evenly distributed
over the entire surface of the plates. The usefulness of this type
of plate heat exchanger is limited to crossflow operation. Because
the channels have too small a cross section, any other mode of
operation, for instance in a counterflow pattern, is rendered
impossible.
[0004] It is the objective of this invention to introduce a plate
heat exchanger which permits counterflow operation, which offers a
high pressure load capacity with respect to both media and which
can be manufactured cost-effectively in terms of materials and
assembly labor.
[0005] As the solution for achieving this objective with a plate
heat exchanger of the type first above mentioned the invention
proposes to provide the plates with parallel rows of trough-shaped
sectional embossments which are located on the same side of all
plates and which are equidistant from one another, with the rows of
consecutive plates superpositioned over one another.
[0006] A plate heat exchanger of this type offers sufficiently
large channel diameters for both media in a counterflow operation.
This plate heat exchanger also features high compressive load
resistance with respect to both media in the heat exchange, and it
can be produced cost-effectively in terms of materials and
labor.
[0007] The sectional embossments of consecutive plates preferably
extend in a mutually offset arrangement in the direction of the
rows. This offset should preferably correspond to half the length
of a sectional embossment.
[0008] In an enhanced design variation the sectional embossments of
the neighboring rows of a plate are mutually offset in the
direction of the rows. This offset should again preferably
correspond to half the length of a sectional embossment.
[0009] In another design variation of the plate heat exchanger
according to this invention, the plates making up the plate stack
are rectangular, with the intake and the outflow of the first
heat-exchange medium taking place on the two short sides of the
plates while the intake of the second heat-exchange medium takes
place at one end and its outflow at the other end on the long sides
of the plates. The rows composed of the sectional embossments
preferably extend parallel to the short sides of the plates.
[0010] In the attached drawings which show examples of this
invention
[0011] FIG. 1 is a schematic illustration of two plate heat
exchangers serving as recuperators for gas turbines;
[0012] FIG. 2 represents the plate heat exchangers serving as
recuperators with a functional pattern differing from that in FIG.
1;
[0013] FIG. 3 represents the plate heat exchangers serving as
recuperators with a functional pattern differing from that in FIG.
1 and FIG. 2;
[0014] FIG. 4 is a perspective view of a plate heat exchanger
composed of a stack of ten plates; and
[0015] FIG. 5 is an enlarged perspective view of the plates in the
plate stack.
[0016] By way of a first design example, FIG. 1 shows possible
deployment modes of a plate heat exchanger serving as a gas-turbine
recuperator. The reference number 1 identifies the exit port for
the hot turbine gases. These gases reach temperatures for instance
as high as 650.degree. C. (1202.degree. F.). The hot gases flow
through the two co-symmetrically configured plate heat exchangers 2
in the direction of the longitudinal axis of the latter and exit
into a joint discharge channel 3. In the discharge channel 3 the
temperature of the turbine exhaust gases is still about 200.degree.
C. (392.degree. F.).
[0017] The compressed air fed to the gas turbine travels through
the plate heat exchangers 2 in a counterflow direction, for which
purpose one end of each plate heat exchanger 2 is provided with an
intake channel 4 while the other end features a joint discharge
channel 5. In the intake channel 4 the temperature of the
compressed air may be for instance 175.degree. C. (347.degree. F.),
in the discharge channel 5 shared by both plate heat exchangers 2
it may be about 600.degree. C. (1112.degree. F.).
[0018] FIG. 1 also indicates that the two plate heat exchangers 2
are angled relative to each other in such fashion that the distance
A between them in the area of the common discharge channel 5 is
greater than at the level of the separate intake channels 4 of the
two plate heat exchangers. The reason for this is that, while the
first medium, being the hot gas emanating from the turbine, enters
and exits strictly on the short sides 6 of the plate heat
exchanger, the second heat-exchange medium, being the compressed
air, enters and exits respectively on the long sides 7a, 7b of the
plate heat exchanger 2. This means that the intake channel 4 is
located at one end of the long side 7a while the discharge channel
5 is located at the other end of the long side 7b. This could be
considered to constitute a partly diagonal flow of the second
medium, i.e. the compressed air, through the plate heat exchangers
2.
[0019] In the design example per FIG. 2, the intake channel 4 for
the second medium and the discharge channel 5 are located on the
same long side 7b of the plate heat exchanger 2 while the other
long side, 7a, is completely closed. Both the intake channel 4 and
the discharge channel 5 are in the middle between the paired plate
heat exchangers 2 and equally serve both plate heat exchangers. In
the design example per FIG. 2 as well, the media travel in a
counterflow direction, except that in this case the main flow
direction of the second medium follows a "C" pattern. The first
medium again flows through the plate heat exchangers in a straight
line between the exit port 1 of the gas turbine and the discharge
channel 3.
[0020] The design example per FIG. 3 differs from that per FIG. 2
by virtue of additional intake channels 4 and discharge channels 5
also on the long side 7a of the plate heat exchangers 2 which are
again paired. Thus, each long side 7a, 7b of the two plate heat
exchangers 2 features both an intake channel 4 and a discharge
channel 5 for the second heat-exchanging medium. The pattern of the
counterflow resembles an elongated "X".
[0021] Details of the plate heat exchanger design examples 1 to 3
are described below with reference to FIGS. 4 and 5.
[0022] FIG. 4 again illustrates the intake and discharge flow
vectors 1, 3, 4, 5 from the gas-turbine exit port 1, of the
discharge channel 3 as well as the intake channel 4 and discharge
channel 5 of the air to be heated. It can also be seen that the
plate heat exchanger 2 is composed of multiple stacked steel plates
each of which is provided with embossments. Embossed plates of this
type can be produced by a deep-draw process or by means of an
appropriate stamping press. With the exception of the perimeter of
the individual plate 8, all sectional embossments 9 on the plate
are identical and are in the form of straight troughs of limited
length. In the illustration per FIG. 4 and 5, the plates 8 are
stacked one atop the other in such fashion that the cambered sides
of the trough-shaped sectional embossments 9 point upward.
[0023] All trough-shaped sectional embossments 9 are rectangular
and of the same length L, with the exception of the end sections
described further below. Within a row, the consecutive sectional
embossments 9 are uniformly spaced apart over the entire plate 8 by
a distance a. The sectional embossments 9 are arranged in rows
which extend in the direction parallel to the longest dimension of
the rectangular sectional embossments 9. The individual rows on the
plate 8 extend parallel to one another and are uniformly spaced
apart by a distance .tau.. In the direction of the rows, the
sectional embossments 9 of neighboring rows are offset in relation
to one another, the offset V corresponding to half the length of
the embossments 9. Viewed from the top, the array of sectional
embossments 9 thus resembles a masonry wall with the bricks
staggered on-center.
[0024] This offset V results in half-length sectional embossments
9' along the long sides 7a, 7b of each plate 8. Accordingly, the
embossment rows which start with a full-length embossment 9
alternate with rows beginning with a half-length sectional
embossment 9', as is clearly illustrated in FIG. 4. As is
especially recognizable in FIG. 5, the rows of trough-shaped
sectional embossments 9 and 9' are situated on the same side of
each plate 8 in the plate heat exchanger 2. It follows that all of
the embossments 9 protrude in the same direction i.e. either upward
or downward depending on the viewing angle. If all plates 8 were
identical in shape and positioning, these plates and their
sectional embossments would sit in flush, form-fitted fashion one
atop the other with no gap in between, eliminating any flow
channels between the plates. Therefore, according to this
invention, any two juxtapositioned plates will have a mutually
different pattern of sectional embossments 9, 9' so that by virtue
of their arrangement the embossments 9, 9' serve as spacers. This
is accomplished by mutually offsetting the embossments 9, 9' of
neighboring plates 8 so as to avoid an exact match. As can be seen
in FIG. 5, this offset V between neighboring plates corresponds to
half the length of a trough-shaped sectional embossment 9. However,
there is no offset between the individual rows of embossments 9, 9'
on neighboring plates 8, meaning that the rows of one plate are
situated precisely above the rows of the following plate in the
plate stack. The offset V.sub.P is provided only within the row
itself. To that end, the individual plates 8 are stacked in such
fashion that a plate whose row begins with a full-length sectional
embossment 9 is followed by a plate whose row begings with a
half-length sectional embossment 9', and vice versa. In terms of
their manufacture, one approach would be to produce two different
plate models. As a second possibility, all plates could be
identical but in the stacking process every other plate is
horizontally rotated by 180.degree. and then placed on the plate
beneath it, before all plates are firmly connected.
[0025] As a result of the above-described configuration and
arrangement of the individual plates 8, the sectional embossments
9, 9' cause each such plate to be supported by the next plate in
the direction in which the sectional embossments extend. This is
due to the contact between the embossments 9, 9' of one plate and
the points 10 of the next following plate. These contact points 10
are unembossed areas of the base surface of that next following
plate which areas are situated between the embossments 9 of a given
row and separate the sectional embossments 9 of that row.
[0026] For producing the plate heat exchanger 2, the individual
plates 8 are welded together at their short sides 6 and their long
sides 7a, 7b, as can be seen in FIG. 4. The assembly is made in in
a way as to allow, in alternating fashion, the flow of one and then
of the other heat-exchanging media between the plates. Accordingly,
if two neighboring plates form the flow channels for the first
medium, the next following plates will form the flow channels for
the other medium. To provide the short sides 6 with the necessary
intake and discharge openings, the short sides 6 of the plates 8
feature contoured end sections 11 whose height corresponds to the
height of the embossments 9. As shown in FIG. 4, the areas of the
two long sides 7a, 7b which contain neither intake channels 4 nor
discharge channels 5 are completely closed, thus forcing a
counterflow between the two heat-exchanging media.
* * * * *