Note: Descriptions are shown in the official language in which they were submitted.
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HEAT EXCHANGER MODULE AND HEAT EXCHANGER SYSTEM WITH
PROJECTING MEMBERS
The present invention relates to a heat exchanger module and a heat exchanger
system for transfer of heat between different media, in particular a heat
exchanger
module for preheating materials that are to be employed in a process for
biogas
production, such as liquid manure, industrial process water, sludge and/or
ooze.
In many biogas systems the biological material entering the system has a low
temperature and requires heating before entering process tanks operating at
different
temperatures. On the other hand, material from the process tanks may have a
high
temperature and requires a lowering of the temperature.
Heat exchangers employing a heat transporting medium, such as water, for
transfer of
heat between two reservoirs by circulating the heat transporting medium in a
closed
loop submerged in the two reservoirs are known. Such heat exchangers usually
have a
low efficiency.
Counterflow heat exchangers for liquid manure are often built as tube in tube
and
require frequent cleaning. Cleaning of these heat exchangers is usually very
difficult
due to the construction or involves a heavy wear on the material of the heat
exchanger
when using acid.
Known heat exchangers have tubular flow channels of different cross sections.
For
example, WO 2007/059770 describes a heat exchanger module and a heat exchanger
system for heat transfer between a first fluid flowing in a first flow channel
and a
second fluid flowing in a second flow channel. The flow channels have a
substantially
uniform cross section through the heat exchanger module. Even though the heat
exchanger system disclosed in WO 2007/059770 provides an improvement, there is
still a need for a more efficient heat exchanger with an improved transfer of
heat
between the media in the respective flow channels.
It is a problem of known heat exchangers that the heat transfer between media
in
respective flow channels is low, which reduces the efficiency of the heat
exchanger.
Accordingly it is an object of the present invention to provide a heat
exchanger with
improved heat transfer between two media in a heat exchanger.
It is also an object of the present invention to provide a medium flow having
a
substantially uniform temperature profile across the flow channel.
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Further, it is among the objects of the present invention to provide a heat
exchanger
that has a high efficiency and that is easy to maintain, e.g. easy to clean.
It is also among the objects of the present invention to provide a heat
exchanger
capable of providing efficient heat exchange between different media, in
particular
manure, such as liquid manure, industrial process water, sludge and/or ooze.
Typically,
these media are characterized by a large content of dry matter, such as
organic
material, e.g. straw, faeces and waste, dissolved in a liquid, such as water,
urine or the
like.
Accordingly, a heat exchanger module is provided, wherein the heat exchanger
module
has walls defining flow channels and comprising a first flow channel having
one or
more first sections extending along a first axis and positioned in thermal
contact with a
second flow channel having one or more second sections extending along the
first axis
for heat exchange between a first medium flowing in the first flow channel and
a
second medium flowing in the second flow channel. The heat exchanger module
may
comprise a first projecting member attached to a wall and extending into the
first flow
channel, such that first medium flowing in the first flow channel is
redirected when
passing the first projecting member.
Further, a heat exchanger system is provided, comprising one or more heat
exchanger
modules as described herein. Preferably, the heat exchanger system comprises a
first
heat exchanger module and a second heat exchanger module that are
interconnected
to form a first flow channel and a second flow channel, e.g. by one or more
module
connectors, such as fittings.
The heat exchanger module may comprise a plurality of first projecting members
attached to one or more walls and extending into the first flow channel, such
that first
medium flowing in the first flow channel is redirected when passing the
plurality of first
projecting members. One or more of the first sections, e.g. each of the first
sections, of
the first flow channel may comprise one or more first projecting members, such
as one,
two, three, four, five, six, seven, eight, nine, ten or more first projecting
members. The
number of first projecting members in a first section may be chosen according
to the
intended use of the heat exchanger module, e.g. properties of the first
medium, the
length of the first section and/or desired turbulence in the first flow
channel.
Furthermore, the heat exchanger module may comprise a second projecting member
attached to a wall and extending into the second flow channel, such that
second
medium flowing in the second flow channel is redirected when passing the
second
projecting member.
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Additionally, the heat exchanger module may comprise a plurality of second
projecting
members attached to one or more walls and extending into the second flow
channel,
such that second medium flowing in the second flow channel is redirected when
passing the plurality of second projecting members. One or more of the second
sections, e.g. each of the second sections, of the second flow channel may
comprise
one or more second projecting members, such as one, two, three, four, five,
six, seven,
eight, nine, ten, or more second projecting members. The number of second
projecting
members in a second section may be chosen according to the intended use of the
heat
exchanger module, e.g. properties of the second medium, the length of the
second
section and/or desired turbulence in the second flow channel.
The projecting members in the flow channels create turbulence in the media
flowing in
the flow channels. The turbulence causes mixing of the medium leading to a
more
uniform temperature profile across the flow channel. Thereby improved transfer
of heat
between the media flowing in the flow channels is obtained compared to a
substantially
laminar flow. It may be desired to have as low drop of pressure as possible
from the
inlet to the outlet of the flow channel to reduce the consumption of energy in
moving
the medium through the flow channel. However a low drop of pressure requires
low
turbulence in the flow, i.e. a substantially laminar flow.
Surprisingly, the present inventors have found that a considerable improvement
in the
heat transfer between the media and thus a more efficient heat exchanger can
be
obtained by employing projecting members in the flow channels. At the same
time, a
relatively low increase in drop of pressure has been observed. The advantages
of the
improvement heat transfer exceed the disadvantages of an increased drop of
pressure.
Preferably, the heat exchanger module has a body with walls including a first
outer
wall, a first end wall, and a second end wall. In an embodiment, the heat
exchanger
module further comprises a second outer wall, a third outer wall, and a fourth
outer
wall. Further, the heat exchanger module may comprise inner walls forming a
plurality
of cavities or sections of flow channels in the body of the heat exchanger
module.
Preferably, an inner wall forms a common wall between a first section and a
second
section of the first flow channel and the second flow channel, respectively. A
single wall
forming a common wall between different flow channel sections provides
efficient heat
transfer between the media in the respective flow channels.
Preferably, the walls defining the sections of the flow channels are plane and
may be
parallel to the first axis. However, the walls may be curved, e.g. to form a
flow channel
section having a smooth, non-polygonal cross section.
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Preferably, the projecting members are formed and/or attached to the walls
such as to
minimize the risk of catching medium and/or dry matter, such as straw or
tissue in
slaughterhouse waste. Dry matter or other objects caught by the projecting
members
may lead to blocking or narrowing of the flow channel, which thus requires
cleansing.
Preferably, the first projecting member(s) and/or the second projecting
member(s)
is/are substantially plane. Plane members are preferred due to the production
process;
however one or more of the projecting members may in an embodiment of the
present
invention have a curved surface to obtain a smoother redirection of the flow.
In a preferred embodiment of present invention, the first projecting member(s)
and/or
the second projecting member(s) is/are substantially perpendicular to the wall
to which
it/they are attached, e.g. to reduce the risk of deposition of medium or dry
matter, such
as straw. However, one or more of the projecting member(s) may be tilted in
relation to
the wall, e.g. at an angle from about from about 45 to 90 , such as about 65
, about
75 or about 85 .
The first projecting member(s) and/or the second projecting member(s) may form
an
angle with the first axis, the angle being less than 70 , such as from about 5
to about
60 , preferably from about 15 to about 45 . In a preferred embodiment of the
present
invention, the first projecting member(s) and/or the second projecting
member(s)
forms/form an angle with the first axis from about 20 to about 30 .
The projecting members may have a first edge between a first point and a
second
point, respectively. The projecting members may be attached, e.g. by welding,
to a wall
of the heat exchanger module along second edges. Preferably, the first edge is
formed
in such a way that dry matter or other objects in the medium are prevented
from being
caught by the projecting members and eventually blocking or narrowing the flow
channel into which the projecting members projects.
In general, projecting members may be formed such that tangents of the first
edge from
a first intermediate point to a middle point along the first edge form tangent
angles with
the first axis, such that dry matter, e.g. straw, flowing along the first axis
in the flow
channel is not caught by the projecting member. Furthermore, in order to
provide a flow
channel adapted for flow in both directions along the first axis, projecting
members may
be formed such that tangents of the first edge from the middle point to a
second
intermediate point along the first edge form tangent angles with the first
axis, such that
dry matter, e.g. straw, flowing along the first axis in the flow channel is
not caught by
the projecting member.
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In general, it is important that the first edge at least from a small distance
of the first
and second points, is not perpendicular to the first axis.
Preferably, the tangent angles with the first axis parallel to the second edge
of the
projecting member from the first intermediate point to the middle point lie in
the range
5 from about -85 to about 85 , preferably in the range from about -75 to
about 75 ,
more preferably in the range from about -60 to about 60 . In a preferred
embodiment,
the tangent angles with the first axis parallel to the second edge of the
projecting
member from the first intermediate point to the middle point lie in the range
from about
-45 to about 45 , such as in the range from about -30 to about 30 .
Preferably, the tangent angles with the first axis parallel to the second edge
of the
projecting member from the middle point to the second intermediate point lie
in the
range from about -85 to about 85 , preferably in the range from about -75 to
about
75 , more preferably in the range from about -60 to about 60 . In a preferred
embodiment, the tangent angles with the first axis parallel to the second edge
of the
projecting member from the middle point to the second intermediate point lie
in the
range from about -45 to about 45 , such as in the range from about -30 to
about 30 .
Preferably, the tangent angles with the first axis parallel to the second edge
of the
projecting member from the first point to the first intermediate point lie in
the range from
about 0 to about 85 , preferably in the range from about 0 to about 60 ,
more
preferably in the range from about 0 to about 45 .
Preferably, the tangent angles with the first axis parallel to the second edge
of the
projecting member from the second intermediate point to the second point lie
in the
range from about -85 to about 0 , preferably in the range from about -60 to
about 0 ,
more preferably in the range from about -45 to about 0 .
The first edge may be formed by a number of linear edge portions connected by
curved
or rounded edge portions.
In general, first edge portions may form angles with the first axis parallel
to the second
edge of the projecting member in the range from about -75 to about 75 ,
preferably in
the range from about -45 to about 45 .
The first intermediate point on the first edge is close to the first point,
e.g. at a distance
of about 10 mm or less than 10 mm, such as about 5 mm, 3 mm or 2 mm, from the
first
point, and the second intermediate point on the first edge is close to the
second point,
e.g. at a distance of about 10 mm or less than 10 mm, such as about 5 mm, 3 mm
or 2
mm, from the second point.
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Preferably, the first and second intermediate points coincide with the first
and second
points, respectively.
The first and/or second projecting member(s) may have a curved edge such that
objects, e.g. straw, tissue from slaughterhouse waste or other objects, in the
medium
passing the projecting member(s) are prevented from being caught by the
projecting
member(s) and subsequently blocking or narrowing the flow channel.
It is an important advantage of an embodiment of the present invention that
the
projecting members are smooth such as to prevent deposit of medium or dry
matter of
the medium.
The first and/or the second projecting member(s) may have any suitable size
and
shape such that a desired turbulence is created in the medium in the flow
channel in
question. In an embodiment of the present invention, the projecting members
extend
about halfway into the flow channel.
In a preferred embodiment of the present invention, the projecting members are
semi-
oval, e.g. with a length of about 13 cm and a width of about 3.6 cm. Other
shapes such
as semi-circular, bell-shaped may also be employed. Typically, the projecting
members
are attached to the walls in such a way that there is a certain distance to
neighbouring
walls to further reduce the risk of deposit of medium or dry matter of the
medium in the
flow channel.
In a preferred embodiment, one or more of the projecting members may be formed
as
a circular segment constituted by the part between a chord (second edge) and
an arc
(first edge) of a circle, excluding the center of the circle.
In an embodiment, one or more of the projecting members may be formed as a
segment constituted by the part between a chord (second edge) and an arc
(first edge)
of an ellipse, excluding at least one of the foci of the ellipse. Preferably,
the chord is
parallel to the major axis.
In a preferred embodiment of the present invention, the projecting members
have an
area less than 100 cm2, such as in the range from about 5 cm2 to about 90 cm2,
preferably from about 20 cm2 to about 60 cm2, more preferably about 30 cm2.
Other
dimensions and shapes may be contemplated according to dimensions of the flow
channels.
It is an important advantage that the heat exchanger module according to the
present
invention can be operated with lower flow velocities for obtaining the same
efficiency
compared to heat exchangers without projecting members.
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Further, it is an advantage of the heat exchanger module according to the
present
invention that a increased surface area is provided for each flow channel,
leading to
improved heat exchange between the first medium in the first flow channel and
second
medium in the second flow channel.
In a preferred embodiment of the present invention, a first section of the
first flow
channel abuts at least three second sections of the second flow channel.
Preferably, the first flow channel and the second flow channel have a
substantially
uniform cross section through the heat exchanger module.
In a preferred embodiment of the heat exchanger module, a second section of
the
second flow channel abuts at least three first sections of the first flow
channel.
Preferably, the walls in the heat exchanger module form a plurality of
cavities to form at
least two flow channels. For example, first cavities may be connected via
first
connectors forming a first flow channel and second cavities may be connected
via
second connectors forming a second flow channel. A cavity may form a section
of the
first flow channel or the second flow channel. Preferably a section of a flow
channel is
connected either upstream or downstream to the other sections of the flow
channel, i.e.
in series with the other sections. In an embodiment, one or more sections may
be
connected in parallel.
Preferably, the first flow channel and the second flow channel have common
walls to
improve heat exchange between media in the respective channels. For example, a
first
section of the first flow channel may have a common wall with at least three
different
second sections of the second flow channel, and a second section of the second
flow
channel may have a common wall with at least three different first sections of
the first
flow channel.
The heat exchanger module may have a first port and a second port. The first
port may
form an inlet and/or an outlet at an end of the first flow channel, and the
second port
may form an inlet and/or outlet at the other end of the first flow channel.
Further, the heat exchanger module may comprise a third port and a fourth
port. The
third port may form an inlet and/or an outlet for the second flow channel, and
the fourth
port may form an inlet and/or an outlet for the second flow channel.
The ports may have module connectors, e.g. fittings, for coupling the heat
exchanger
module to other heat exchanger modules and or external units such as a
cleaning
system or containers holding first and second media. Preferably, the module
connectors when inter-coupling heat exchanger modules have a cross section
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corresponding to the cross section of the sections of the flow channels, which
they
communicate or connect.
Preferably, the first sections of the first flow channel are tubular and
second sections of
the second flow channel are tubular. Preferably, the first sections and the
second
sections extend along a straight first axis, e.g. having a length from about
0.5 m to
about 10 m. In a preferred embodiment of the present invention, the sections
have a
length of about 3 m.
In an embodiment of the present invention, the walls of the heat exchanger
module
form a first flow channel with a polygonal cross section. In a preferred
embodiment of
the present invention, the walls of the heat exchanger module form a first
flow channel
with first sections having a four-sided cross section.
In an embodiment of the present invention, the walls of the heat exchanger
module
form a second flow channel with a polygonal cross section. In a preferred
embodiment
of the present invention, the walls of the heat exchanger module form a second
flow
channel with second sections having a four-sided cross section.
The sections of the respective flow channels may have a substantially
polygonal cross
section with side lengths from about 10 mm to about 200 mm, such as from about
30
mm to about 100 mm, e.g. about 50 mm. Preferably, the sections have a four-
sided
cross section, e.g. a rectangular cross section and/or a square cross section,
with side
lengths from about 10 mm to about 200, preferably from about 25 mm to about
100
mm, more preferably from about 30 mm to about 60 mm, such as about 40 mm or
about 50 mm.
The heat exchanger module may be operated with a medium flow velocity of about
0.6
m/s to about 3 m/s, such as from about 0.8 m/s to about 1.7 m/s, e.g. about
1.2 m/s.
In a preferred embodiment of the present invention, one or more of the
sections of the
flow channels, preferably all, have a square cross section with a side length
from about
mm to about 100 mm, such as about 40 mm, about 50 mm, about 60 mm, about 70
mm, or about 80 mm.
In another preferred embodiment of the present invention, the sections of the
flow
30 channels have a rectangular cross section, e.g. having the dimensions 30 mm
x 40 mm
or 40 mm x 50 mm.
Preferably, the first sections and the second sections of the heat exchanger
module are
alternately arranged in two columns including a first column and a second
column such
that a first section in the first column abuts two second sections in the
first column and
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one second section in the second column. Thus, a first section in the first
column may
have a common inner wall with a second section in the first column, a common
inner
wall with another second section in the first column, and a common inner wall
with a
second section in the second column. Preferably, each section is delimited by
or
defined by at least a part of an outer wall.
The heat exchanger module may comprise first connectors. The first connectors
may
connect first sections to form the first flow channel or at least a part
thereof.
Furthermore, the heat exchanger module may comprise second connectors. The
second connectors may connect second sections to form the second flow channel
or at
least a part thereof.
In a preferred embodiment of the present invention, the connectors are welded
to the
outer walls of the heat exchanger module thereby connecting sections of the
respective
flow channels through openings in the outer walls. Preferably, the openings in
the outer
walls are rectangular and/or quadratic having a cross section corresponding to
the
cross section of the sections for provision of substantially uniform flow
channels. In an
embodiment, the connectors are secured in threaded engagement with the walls.
In an
embodiment of the present invention, the connectors may connect sections of
the
respective flow channels through openings in the end walls.
Preferably, the first and/or the second connectors have a cross section
corresponding
to the cross section of the sections which they communicate or connect.
Thereby drop
of pressure around the connector may be minimized or substantially avoided.
Thus, the
connectors may have a polygonal cross section with a side length from about 30
mm to
about 100 mm, such as a square cross section with a side length from about 30
mm to
about 100 mm, such as about 40 mm, about 50 mm, about 60 mm, about 70 mm, or
about 80 mm.
Preferably, the connectors are positioned near or at the ends of the first and
second
sections.
Further, the heat exchanger module may have one or more cleaning holes.
Preferably,
one or more cleaning holes are provided for each of the cavities forming the
sections of
the flow channels. In a preferred embodiment, a cleaning hole for each of the
cavities
forming the sections of the flow channels is provided, e.g. in the first end
wall of the
heat exchanger module. More preferably, a cleaning hole for each of the
cavities
forming the sections of the flow channels may further be provided in the
second end
wall of the heat exchanger module. The one or more cleaning holes may comprise
an
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engagement member, e.g. a threading or a bayonet socket that may be adapted
for
engagement with a plug member. The one or more cleaning holes provide user
access
to the different sections of the heat exchanger thereby facilitating manual
cleaning or
removal of blockages in the flow channel.
5 Further, the heat exchanger module may comprise one or more plug members for
sealing the one or more cleaning holes. The one or more plug members comprise
an
engagement member, e.g. a threading or a bayonet socket, for detachable
engagement with the engagement member of a cleaning hole.
It is an important advantage of the present invention that a user has easy
access to the
10 different sections of the flow channels for convenient removal of any
blockages that
may arise during use. The plug members are readily detachable and mountable.
Preferably, the heat exchanger module is made of stainless steel, such as AISI
304 or
AISI 316, however any other suitable steel type may be used.
Preferably, the heat exchanger module is made of an acid-resistant steel type.
Hereby
cleaning of the heat exchanger with acidic media is rendered possible.
In an embodiment suitable for non-aggressive media, at least a part of the
heat
exchanger module, e.g. the inner walls and/or the outer walls, may be made of
a metal
having high thermal conductivity compared to stainless steel, such as black
steel,
aluminum, or copper. In an embodiment, the walls may be coated with an acid
resistant
material.
In an embodiment of the present invention, first medium having a first inlet
temperature
is pumped into the first flow channel through the first port, passes the first
flow channel
while exchanging heat with medium in the second flow channel, and leaves the
first
flow channel having a first outlet temperature through the second port. At the
same
time, a second medium having a second inlet temperature may be pumped into the
second flow channel through the third port, passing the second flow channel
while
exchanging heat with medium in the first flow channel, and leaving the second
flow
channel having a second outlet temperature through the fourth port.
The heat exchanger module is in particular adapted for heat exchange between
manure, e.g. liquid manure; however, the media may be any media, such as
manure,
e.g. liquid manure, sludge, water or other fluids in liquid and/or gaseous
form, oil,
natural gas, mixtures thereof, or the like.
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It is an important advantage of the present invention that the heat exchanger
due to its
construction is compact and takes up little space compared to the amount of
heat
transferred.
It is an important advantage of the present invention that the heat exchanger
is able to
transfer large amounts of heat between the media in the respective flow
channels.
It is a further advantage of the present invention that cleaning of the heat
exchanger
module is easy and can be performed without destroying, e.g. cutting, the heat
exchanger module.
The walls of the heat exchanger module may have a thickness in the range from
about
0.5 mm to about 20 mm, preferably from about 1 mm to about 10 mm. In a
preferred
embodiment of the present invention, the walls of the heat exchanger have a
thickness
from about 2 mm to about 5 mm, e.g. about 3 mm or about 4 mm. If the thickness
of
the walls is too small, a high pressure may not be employed, and if the
thickness of the
walls is too large, the transfer of heat between the first and second flow
channel is
reduced.
It may be desired to employ a high pressure in the flow channels. If the first
pressure in
the first flow channel and the second pressure in the second flow channel are
substantially the same, or the pressure difference between the first flow
channel and
the second flow channel is small, e.g. less than 3 bar, the thickness of the
inner walls
of the heat exchanger module can be small, such as around 1 mm, thereby
obtaining
improved heat exchange between the media.
The heat exchanger module may further comprise a casing. The casing supports
and
strengthens the outer walls to increase the possible operating pressures of
the heat
exchanger module. The heat exchanger module with or without a casing may
operate
with media at a high pressure, e.g. up to 12 bar or more.
The heat exchanger system according to the present invention may comprise one
or
more heat exchanger modules as described herein, such as two, three, four,
five, ten,
twenty, fifty or more heat exchanger modules. In a preferred embodiment, the
heat
exchanger system comprises a first heat exchanger module and a second heat
exchanger module as described herein. Preferably, the heat exchanger system
comprises a frame carrying the one or more heat exchanger modules. Further,
the heat
exchanger system may comprise a plurality, e.g. two three, four or more
insulation
elements for insulation of the heat exchanger modules. The insulation elements
may
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be attached to the frame, e.g. by one or more hinges and/or adapted to support
on the
frame.
In the heat exchanger system, one or more ports functioning as inlet/outlet of
a flow
channel may be provided with fittings, e.g. a T-piece, to allow easy coupling,
e.g. via
valves, of the flow channel to different medium loops, such as a medium loop
with
liquid manure and a medium loop with cleaning fluid.
Preferably, the heat exchanger system according to the invention comprises one
or
more module connectors, such as fittings, that connect ports of the heat
exchanger
modules according to a desired configuration of the heat exchanger system,
e.g.
depending on the number of media to be heat exchanged, number of heat
exchanger
modules, etc.
Preferably, the module connectors have a cross section corresponding to the
cross
section of the sections of the heat exchanger modules, which they communicate
or
connect. Thereby drop of pressure around the module connector may be minimized
or
substantially avoided. Thus, the module connectors may have a polygonal cross
section with a side length from about 30 mm to about 100 mm, such as a square
cross
section with a side length from about 30 mm to about 100 mm, such as about 40
mm,
about 50 mm, about 60 mm, about 70 mm, or about 80 mm.
Preferably, first medium in a first section flows in the opposite direction of
the flow of
the second medium in two adjacent second sections.
The invention will now be described in further detail with reference to the
enclosed
drawings, wherein
Fig. 1 is a perspective view of an embodiment of a heat exchanger
module according to the present invention,
Fig. 2 is another perspective view of the embodiment illustrated in Fig. 1,
Fig. 3 shows a perspective cross section of the heat exchanger module
illustrated in Fig. 1,
Fig. 4 is a side view of a side of the heat exchanger module illustrated in
Fig. 1,
Fig. 5 is a side view of the opposite side of the heat exchanger module
illustrated in Fig. 1,
Fig. 6 shows the side view of Fig. 5 omitting parts of the heat exchanger
module,
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Fig. 7 schematically illustrates a cross section of the heat exchanger
module of Fig. 1
Fig. 8 schematically illustrates a cross section of a heat exchanger
module according to the present invention,
Fig. 9 schematically illustrates a cross section of a heat exchanger
module according to the present invention,
Fig. 10 schematically shows a plan view of a wall with projecting members
of a heat exchanger module according to the present invention,
Fig. 11 is a surface view of an exemplary projecting member,
Fig. 12 is a top view of the wall illustrated in Fig. 10,
Fig. 13 and Fig. 14 show different views of exemplary projecting
members,
Fig. 15 schematically shows a plan view of a wall of a heat exchanger
module according to the present invention,
Fig. 16 schematically illustrates an embodiment of a heat exchanger
system according to the invention,
Fig. 17 schematically illustrates operation of the heat exchanger system
shown in Fig. 10,
Fig. 18 schematically illustrates operation of an embodiment of a heat
exchanger system according to the present invention, and
Fig. 19 is a surface view of an exemplary projecting member.
In the drawings, corresponding parts of the illustrated embodiments have the
same
reference numerals.
Figs. 1-7 schematically show a preferred embodiment of a heat exchanger module
according to the present invention. The heat exchanger module 2 has walls and
comprises a first flow channel positioned in thermal contact with a second
flow channel
for heat exchange between a first medium flowing in the first flow channel and
a
second medium flowing in the second flow channel. Further, a first section of
the first
flow channel abuts at least three second sections of the second flow channel,
e.g. the
first section 6Q abuts the second sections 14C, 14D, and 14N. Further, a
second
section of the second flow channel abuts at least three first sections of the
first flow
channel, e.g. the second section 14L abuts the first sections 61, 6J, and 6S.
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A first port 4 and a second port 8 in the heat exchanger module function as
inlet/outlet
to the first flow channel. First sections 6A, 6B, 6C, 6D, 6E, 6F, 6G, 6H, 61,
6J, 6K, 6L,
6M, 6N, 60, 6P, 6Q, 6R, 6S, 6T and first connectors 10A, 10B, 10C, 10D, 10E,
10F,
10G, 10H, 101, 10J, 10K, 10L, 10M, 10N, 100, 10P, 10Q, 10R, 10S form the first
flow
channel. A first connector connects two first sections of the first flow
channel, e.g. the
first connector 10A connects the first sections 6A and 6B, the first connector
10B
connects the first sections 6B and 6C, etc.
The first sections and the second sections are tubular and extend along a
straight first
axis A and having a length of about 3 m.
A third port 12 and a fourth port 16 function as an inlet/outlet to the second
flow
channel. Second sections 14A, 14B, 14C, 14D, 14E, 14F, 14G, 14H, 141, 14J,
14K,
14L, 14M, 14N, 140, 14P, 14Q, 14R, 14S, 14T and second connectors 18A, 18B,
18C,
18D, 18E, 18F, 18G, 18H, 181, 18J, 18K, 18L, 18M, 18N, 180, 18P, 18Q, 18R, 18S
form the second flow channel, each second connector connecting two second
sections
of the second flow channel, e.g. the second connector 18A connects the second
sections 14A and 14B, the second connector 18B connects the second sections
14B
and 14C, etc.
The heat exchanger module 2 comprises first projecting members attached to the
walls
of the heat exchanger module extending into the first sections. In the heat
exchanger
module 2, each first section comprises five first projecting members and each
second
section comprises five second projecting members. Any suitable number of
projections
in a section may be employed such as up to and including ten, or more, e.g.
one, two,
three, four, five, six, ten or more.
In the illustrated embodiment, the projecting members of a section are
attached to the
same wall, however in another embodiment of the present invention another
configuration may be desired, and thus the projecting members in a section may
be
attached to different, e.g. neighbouring and/or opposite, walls.
The first flow channel and the second flow channel have a substantially
quadratic cross
section (about 40 mm X 40 mm) from the first port to the second port and from
the third
port to the fourth port, respectively.
The ports 4, 8, 12, 16 have fittings 4', 8', 12', 16' for connection to other
heat
exchanger modules or external units.
The heat exchanger module 2 has a first outer wall 20, a second outer wall 22,
a third
outer wall 24, a fourth outer wall 26, a first end wall 28, and a second end
wall 30.
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Further, the heat exchanger module 2 comprises inner walls 32A, 32B forming a
plurality of cavities forming sections of the flow channels in the heat
exchanger module.
Preferably, the inner walls of the heat exchanger separate two adjacent
sections
thereby forming a common wall. The outer walls 20, 22, 24, 26 have a thickness
of
5 about 2 mm, and the inner walls 32A, 32B have a thickness of about 2 mm. The
thickness of the walls may be selected according to desired operating pressure
and
optimum heat transfer.
The first connectors and the second connectors connect first sections and
second
sections, respectively, via openings in the outer walls of the heat exchanger
module.
10 A plurality of cleaning holes is formed in the first end wall 28,
preferably one cleaning
hole for each cavity forming a section of a flow channel. In an embodiment
according to
the present invention, a plurality of cleaning holes are formed in the second
end wall 30
(not shown) preferably one cleaning hole for each cavity forming a section of
a flow
channel. The one or more cleaning holes have a threading for engagement with a
15 corresponding plug member.
The heat exchanger module 2 further comprises a plurality of plug members 34
for
sealing the cleaning holes in the end walls. The plug members 34 have a
threading for
engagement with the engagement member of a cleaning hole. The plug members may
be unscrewed, thereby providing user access to the heat exchanger module.
Fig. 7 schematically illustrates a cross section of the heat exchanger module
2
according to the present invention. Inner walls 32A, 32B separate cavities or
first
sections 6A, 6B,..., 6T forming a part of the first flow channel from cavities
or second
sections 14A, 14B,..., 14T forming a part of the second flow channel. Each
section of
the first and second flow channels except the first sections 6A, 6T and the
second
sections 14J, 14K abuts three different sections of the other flow channel.
The heat
exchanger module 2 has twenty first sections 6A, 6B, ..., 6T and twenty second
sections 14A, 14B, ..., 14T. The first sections and the second sections are
arranged in
two columns including a first column comprising ten first sections 6A, 6B,
..., 6J and
ten second sections 14K, 14L, .., 14T, and a second column comprising ten
first
sections 6K, 6L, ..., 6T and ten second sections 14A, 14B, .., 14J. The
sections have a
square cross section with a side length of 40 mm. In the heat exchanger module
2, the
projecting members are attached to the vertical inner walls 32A. In another
embodiment, one or more projecting members may be attached to the horizontal
inner
walls 32B and/or to the outer walls 20, 22, 24, 26. Different projecting
members of a
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section extending into a flow channel may be attached to different walls
defining the
section.
Fig. 8 schematically illustrates a cross section of another embodiment of the
heat
exchanger module 102 corresponding to the embodiment of Fig. 1-7 except that
the
heat exchanger module 102 has fewer first and second sections and accordingly
fewer
first and second connectors. The heat exchanger module 102 has ten first
sections 6A,
6B, ..., 6J and ten second sections 14A, 14B, ..., 14J. The first sections and
the
second sections are arranged in two columns including a first column
comprising five
first sections 6A, 6B, ..., 6E and five second sections 14F, 14G, .., 14J, and
a second
column comprising five first sections 6F, 6G, ..., 6J and five second sections
14A, 14B,
.., 14E. The sections have a square cross section with a side length of about
40 mm.
First connectors (not shown) connect the first sections and second connectors
connect
the second sections to form the first flow channel and the second flow
channel,
respectively.
Fig. 9 schematically illustrates a cross section of another embodiment of the
heat
exchanger module 202 corresponding to the embodiment of Fig. 1-7 except that
the
heat exchanger module 202 has fewer first and second sections and accordingly
fewer
first and second connectors. The exchanger module 202 has four first sections
6A, 6B,
6C, 6D and four second sections 14A, 14B, 14C, 14D. The first sections and the
second sections are arranged in two columns including a first column
comprising two
first sections 6A, 6B and two second sections 14C, 14D, and a second column
comprising two first sections 6C, 6D and two second sections 14A, 14B. The
sections
have a square cross section with a side length of about 50 mm. First
connectors (not
shown) connect the first sections and second connectors connect the second
sections
to form the first flow channel and the second flow channel, respectively.
Fig. 10 shows an embodiment of a vertical inner wall 32A that may form one or
more of
the vertical inner walls of the heat exchanger modules 2, 102, 202. Five
projecting
members 40 are attached to one side of the vertical inner wall 32A extending
into a
section of a flow channel, e.g. into a first section 6C of the first flow
channel thereby
forming first projecting members. The plane projecting members 40 are
perpendicular
to the vertical inner wall 32A and each form an angle a with the first axis A.
The angle a
may be less than 70 . In the illustrated embodiment, the projecting members
form an
angle a with the first axis from about 20 to about 30 . On the other side of
the vertical
inner wall 32A corresponding projecting members are attached and extending
into
another section of a flow channel, e.g. into the second section 14H in Fig. 7
thereby
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forming second projecting members. Preferably, a first projecting member and a
second projecting member are formed in one piece and mounted, e.g. by welding,
in a
slit in a wall.
Fig. 11 shows the projecting member 40 in Fig. 10 in surface view. The
projecting
member 40 has a semi-oval shape with a curved edge 42 and a substantially
straight
edge 44. The projecting member 40 is attached, e.g. by welding, to a wall of
the heat
exchanger module along the straight edge 44. The projecting member 40 may form
a
first projecting member and/or a second projecting member. The width D, is 3.6
cm
corresponding to half the width of the flow channels in the heat exchanger
module 2,
and the length D2 is about 13 cm. D, and D2 may have any suitable size, e.g.
D, may
be in the range from about 0.5 cm to about 10 cm and D2 may be in the range
from
about 2 cm to about 30 cm, depending on the proportions of the flow channel
and the
media flowing in the flow channel.
The curved first edge 42 between a first point 45a and a second point 45b.The
first
edge 42 is formed in such a way that dry matter or other objects in the medium
are
prevented from being caught by the projecting members and eventually blocking
or
narrowing the flow channel into which the projecting members projects.
The projecting member 40 is formed such that tangents of the first edge 42
from a first
intermediate point 47a to a middle point 47b along the first edge form tangent
angles R,
with the first axis in the range from about 0 to about 45 , such that dry
matter, e.g.
straw, flowing along the first axis in the flow channel is not caught by the
projecting
member. Furthermore, in order to provide a flow channel adapted for flow in
both
directions along the first axis, the projecting member 40 is formed such that
tangents of
the first edge 42 from the middle point 47b to a second intermediate point 47c
along
the first edge 42 form tangent angles P2with the first axis in the range from
about -45
to about 0 , such that dry matter, e.g. straw, flowing along the first axis in
the flow
channel is not caught by the projecting member. In the projecting member 40,
the first
intermediate point 47a is at a distance from the first point 45a of about 3
mm, and the
second intermediate point 47c is at a distance from the second point 47c of
about 3
mm.
In general, it is important that the first edge, at least from a small
distance of the first
and second points, is not perpendicular to the first axis.
Preferably, the tangent angles P from the first intermediate point to the
middle point lie
in the range from about -85 to about 85 , preferably in the range from about -
60 to
about 60 , more preferably in the range from about -45 to about 45 .
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Preferably, the tangent angles from the middle point to the second
intermediate point
lie in the range from about -85 to about 85 , preferably in the range from
about -60 to
about 60 , more preferably in the range from about -45 to about 45 .
Fig. 12 shows a top view of a part of the inner wall 32A of Fig. 10. A first
projecting
member 40A and a second projecting member 40B are attached to the wall 32A as
one
member inserted in a slit in the wall 32A.
Fig. 13 shows a vertical inner wall 32A with exemplary projecting members 46,
48, 50
extending perpendicularly from the wall 32A. The projecting members 46, 48, 50
have
curved surfaces for mixing medium flowing in the flow channel, which the
projecting
members 46, 48, 50 extend into. In an embodiment, the projecting members 46,
48, 50
may be plane.
Fig. 14 shows plan surface views of the curved projecting members 46, 48, 50.
In an
embodiment of the present invention, the projecting members may be plane. The
projecting members 46, 48, 50 have first edges 46a, 48a, 50a, respectively,
between a
respective first point 45a and second point 45b. The projecting members 46,
48, 50 are
attached, e.g. by welding, to a wall of the heat exchanger module along
straight second
edges 46b, 48b, 50b, respectively.
The first edges 46a, 48a, 50a are formed in such a way that dry matter, e.g.
straw, or
other objects in the medium are prevented from being caught by the projecting
members 46, 48, 50 and eventually blocking or narrowing the flow channel into
which
the projecting members 46, 48, 50 projects.
The projecting member 46 is formed such that tangents of the first edge 46a
from a first
intermediate point 47a to a middle point 47b along the first edge 46a form
tangent
angles P, with the first axis parallel to the second edge 46b in the range
from about 0
to about 75 to avoid blockage or narrowing of the flow channel by dry matter
being
caught by the projecting member. Further, the projecting member 46 is formed
such
that tangents of the first edge 46a from the middle point 47b to a second
intermediate
point 47c along the first edge 46a form tangent angles P2 with the first axis
parallel to
the second edge 46b in the range from about -75 to about 0 . In the
projecting
member 46, the first intermediate point 47a is at a distance from the first
point 45a of
about 2 mm, and the second intermediate point 47c is at a distance from the
second
point 47c of about 2 mm. The first edge 46a has two curved edge portions 49a,
49b
and a substantially straight edge portion 49c.
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The projecting member 48 is formed such that tangents of the first edge 48a
from a first
intermediate point 47a to a middle point 47b along the first edge 48a form
tangent
angles P, with the first axis parallel to the second edge 48b in the range
from about 0
to about 60 to avoid blockage or narrowing of the flow channel by dry matter
being
caught by the projecting member. Further, the projecting member 48 is formed
such
that tangents of the first edge 48a from the middle point 47b to a second
intermediate
point 47c along the first edge 48a form tangent angles P2 with the first axis
parallel to
the second edge 48b in the range from about -60 to about 0 . In the
projecting
member 48, the first and second intermediate points 47a, 47b coincide with the
first
and second points 45a, 45b, respectively.
The projecting member 50 is formed such that tangents of the first edge 50a
from a first
intermediate point 47a to a middle point 47b along the first edge 50a form
tangent
angles R, with the first axis parallel to the second edge 50b in the range
from about 0
to about 30 to avoid blockage or narrowing of the flow channel by dry matter
being
caught by the projecting member. Further, the projecting member 48 is formed
such
that tangents of the first edge 50a from the middle point 47b to a second
intermediate
point 47c along the first edge 50a form tangent angles P2 with the first axis
parallel to
the second edge 50b in the range from about -30 to about 0 . In the
projecting
member 50, the first and second intermediate points 47a, 47b coincide with the
first
and second points 45a, 45b, respectively. The first edge 50a has three
straight edge
portions 51 a, 51 b, 51 c connected by curved or rounded edge portions 53a,
53b.
Fig. 15 shows another embodiment of a vertical inner wall 32A with projecting
members 40, 52 on both sides of the wall. The angles a, and a2 may be the same
or
different, e.g. 20 and 30 respectively.
Fig. 16 and Fig. 17 schematically illustrate a heat exchanger system according
to the
invention. The heat exchanger system 302 comprises a first heat exchanger
module 2A
and a second heat exchanger module 2B according to the invention. In the
illustrated
embodiment heat exchanger modules 2A and 2B correspond to the heat exchanger
module 2 schematically illustrated in Figs. 1-7. The heat exchanger system
comprises
a frame 304 carrying the heat exchanger modules 2A and 2B. Further, the heat
exchanger system may comprise a plurality of insulation elements. The heat
exchanger
system 302 comprises six insulation elements 306, whereof two are not shown.
The
insulation elements 306 assist in insulating the heat exchanger system. The
insulation
elements 306 may be movably attached to the frame 304, e.g. by one or more
hinges,
for providing easy access to the heat exchanger modules.
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The first port 4A of the first heat exchanger module 2A and the first port 4B
of the
second heat exchanger module 2B function as an inlet/outlet of a flow channel
in the
heat exchanger system 302. The second port 8A of the first heat exchanger
module 2A
and the second port 8B of the second heat exchanger module 2B are connected by
a
5 module connector 308 thereby forming a flow channel 316 from the first port
4A to the
first port 4B.
The fourth port 16A of the first heat exchanger module 2A and the fourth port
16B of
the second heat exchanger module 2B function as an inlet/outlet of a flow
channel in
the heat exchanger system 302. The third port 12A of the first heat exchanger
module
10 2A and the third port 12B of the second heat exchanger module 2B are
connected by a
module connector 312 thereby forming a flow channel 318 from the fourth port
16A to
the fourth port 16B.
One or more ports functioning as inlet/outlet of a flow channel may be
provided with
fittings, e.g. a T-piece, to allow easy coupling, e.g. via valves, of the flow
channel to
15 different medium loops, such as a medium loop with liquid manure and a
medium loop
with cleaning fluid.
In the heat exchanger system illustrated in Fig. 16, each of the heat
exchanger
modules 2A and 2B are provided with a casing 314A and 314B, respectively, for
reinforcement of the outer walls of the respective modules.
20 Further, Fig. 17 schematically illustrates a way of operating the heat
exchanger system
302. First medium having a temperature TA enters the heat exchanger system at
A
through the first port 4A, passes through the heat exchanger system and leaves
the
system through the first port 4B at B having a temperature TB. Second medium
having
a temperature Tc enters the heat exchanger system at C through the fourth port
16B,
passes through the heat exchanger system and leaves the system through the
fourth
port 16A at D having a temperature TD. Thereby first medium in a first section
flows in
the opposite direction of the flow of the second medium in two adjacent second
sections.
Fig. 18 illustrates an embodiment 402 of a heat exchanger system according to
an
alternative embodiment of the present invention. In the heat exchanger system
402, the
second port 8A of the first heat exchanger module and the second port 8B of
the
second heat exchanger module are connected by a module connector or fittings
404
preferably having a cross section corresponding to the sections of the heat
exchanger
modules, thereby forming a main flow channel 406 from the first port 4A of the
first heat
exchanger module 2A to the first port 4B of the second heat exchanger module
2B as
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schematically illustrated in Fig. 12. The third port 12A and the fourth port
16A of the
first heat exchanger module form inlets/outlets for a first secondary flow
channel 408,
and the third port 12B and the fourth port 16B of the second heat exchanger
module
form inlets/outlets for a second secondary flow channel 410. In this
embodiment, a first
medium in the main flow channel exchanges heat with a second medium in the
first
secondary flow channel in the first heat exchanger module and exchanges heat
with a
third medium in the second secondary flow channel in the second heat exchanger
module.
First medium having a temperature TA enters the heat exchanger system 402 at A
through the first port 4A, passes through the heat exchanger system and leaves
the
system through the first port 4B at B having a temperature TB. Second medium
having
a temperature Tc enters the heat exchanger system at C through the third port
12A,
passes through the heat exchanger system and leaves the system through the
fourth
port 16A at D having a temperature TD. Third medium having a temperature TF
enters
the heat exchanger system at F through the fourth port 16B, passes through the
heat
exchanger system and leaves the system through the third port 12B at E having
a
temperature TE.
The number of heat exchanger modules may be decided according to desired
amount
of heat to be transferred, and the modules may be connected depending on e.g.
number and temperature of media to be heat exchanged, operating pressure, etc.
Fig. 19 illustrates an exemplary projecting member. The projecting member 500
is
formed as a circular segment constituted by the part between a chord 502
(second
edge) and an arc 504 (first edge) of a circle, excluding the center of the
circle. The
length of the second edge 502 may be in the range from about 2 cm to about 30
cm,
depending on the proportions of the flow channel and the media flowing in the
flow
channel, e.g. about 13 cm. The width D, may be in the range from about 0.5 cm
to
about 10 cm, e.g. 3.6 cm corresponding to half the width of the flow channels
in the
heat exchanger module.
In specific embodiments, the invention relates to the following items:
1. A heat exchanger module having walls defining flow channels and comprising
a first
flow channel having one or more first sections extending along a first axis
and
positioned in thermal contact with a second flow channel having one or more
second
sections extending along the first axis for heat exchange between a first
medium
flowing in the first flow channel and a second medium flowing in the second
flow
channel, wherein the heat exchanger module comprises a first projecting member
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attached to a wall and extending into the first flow channel, such that first
medium
flowing in the first flow channel is redirected when passing the first
projecting member.
2. A heat exchanger module according to item 1, wherein the heat exchanger
module
comprises a plurality of first projecting members attached to one or more
walls and
extending into the first flow channel, such that first medium flowing in the
first flow
channel is redirected when passing the plurality of first projecting members.
3. A heat exchanger module according to any of items 1-2, wherein the first
projecting
member(s) is/are substantially plane.
4. A heat exchanger module according to any of the items 1-3, wherein the
first
projecting member(s) is/are substantially perpendicular to the wall to which
it/they are
attached.
5. A heat exchanger module according to any of the items 1-4, wherein the
first
projecting member(s) forms/form an angle with the first axis, the angle being
less than
70 , such as from about 5 to about 60 , preferably from about 15 to about 45
.
6. A heat exchanger module according to item 5, wherein the first projecting
member(s)
forms/form an angle with the first axis from about 20 to about 30 .
7. A heat exchanger module according to any of the items 1-6, wherein the
first
projecting member(s) has/have a curved edge such that dry matter or other
objects in
the first medium are prevented from being caught by the first projecting
member(s) and
eventually blocking or narrowing the first flow channel.
8. A heat exchanger module according to item 7, wherein the first projecting
member(s)
has/have a semi-oval shape.
9. A heat exchanger module according to any of the items 1-8, wherein the heat
exchanger module further comprises a second projecting member attached to a
wall
and extending into the second flow channel, such that second medium flowing in
the
second flow channel is redirected when passing the second projecting member.
10. A heat exchanger module according to item 9, wherein the heat exchanger
module
comprises a plurality of second projecting members attached to one or more
walls and
extending into the second flow channel, such that second medium flowing in the
second flow channel is redirected when passing the plurality of second
projecting
members.
11. A heat exchanger module according to any of the items 9-10, wherein the
second
projecting member(s) is/are substantially plane.
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12. A heat exchanger module according to any of the items 9-11, wherein the
second
projecting member(s) is/are substantially perpendicular to the wall to which
it/they are
attached.
13. A heat exchanger module according to any of the items 9-12, wherein the
second
projecting member(s) forms/form an angle with the first axis, the angle being
less than
70 , such as from about 5 to about 60 , preferably from about 15 to about 45
.
14. A heat exchanger module according to item 13, wherein the second
projecting
member(s) forms/form an angle with the first axis from about 20 to about 30 .
15. A heat exchanger module according to any of the items 9-14, wherein the
second
projecting member(s) has/have a curved edge such that dry matter or other
objects in
the second medium are prevented from being caught by the second projecting
member(s) and eventually blocking or narrowing the second flow channel.
16. A heat exchanger module according to item 15, wherein the second
projecting
member(s) has/have a semi-oval shape.
17. A heat exchanger module according to any of the items 1-16, wherein the
heat
exchanger module comprises a plurality of first sections and at least one
first connector
connecting first sections of the first flow channel.
18. A heat exchanger system comprising one or more heat exchanger modules
according to any of the items 1-17.
19. A heat exchanger system according to item 18, wherein the heat exchanger
system
comprises a first heat exchanger module and a second heat module that are
interconnected by one or more module connectors, such as fittings.
