U.S. patent application number 12/843172 was filed with the patent office on 2011-05-05 for system for cleaning heat exchangers.
This patent application is currently assigned to TAPROGGE GMBH. Invention is credited to Dietmar Altegoer.
Application Number | 20110100599 12/843172 |
Document ID | / |
Family ID | 43430323 |
Filed Date | 2011-05-05 |
United States Patent
Application |
20110100599 |
Kind Code |
A1 |
Altegoer; Dietmar |
May 5, 2011 |
SYSTEM FOR CLEANING HEAT EXCHANGERS
Abstract
A mobile heat exchanger cleaning system, in particular for power
plant heat exchangers, allows a heat exchanger to be safely and
reliably cleaned. The cleaning system has an apparatus for
collecting, introducing and removing cleaning bodies, a pump for
pumping a fluid with cleaning bodies and at least one connector
connected with the apparatus and the pump for releasably connecting
the cleaning system with a heat exchanger.
Inventors: |
Altegoer; Dietmar; (Witten,
DE) |
Assignee: |
TAPROGGE GMBH
Wetter
DE
|
Family ID: |
43430323 |
Appl. No.: |
12/843172 |
Filed: |
July 26, 2010 |
Current U.S.
Class: |
165/95 |
Current CPC
Class: |
F28G 1/12 20130101; F28F
9/0265 20130101 |
Class at
Publication: |
165/95 |
International
Class: |
F28G 1/16 20060101
F28G001/16 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 27, 2009 |
DE |
10 2009 034 868.9 |
Claims
1-13. (canceled)
14. A mobile heat exchanger cleaning system for power plant heat
exchangers, comprising an apparatus for collecting, introducing and
removing cleaning bodies, a pump for pumping a fluid with cleaning
bodies, and connecting means connected to the apparatus and the
pump for the releasable connection of the cleaning system with a
heat exchanger.
15. The mobile heat exchanger cleaning system according to claim
14, wherein the system is connectable with the heat exchanger in
such a manner that, in a usage position, a volume flow flowing
through the heat exchanger essentially corresponds to a volume flow
flowing through at least one of the heat exchanger cleaning system
and the apparatus.
16. The mobile heat exchanger cleaning system according to claim
14, wherein the connecting means comprise: a first connecting
element for the releasably connecting of the cleaning system with
an inlet line of the heat exchanger, and a second connecting
element for the releasably connecting the cleaning system with an
outlet line of the heat exchanger.
17. The mobile heat exchanger cleaning system according to claim
16, wherein: the pump and the apparatus are connected in series,
the apparatus is connected with the first connecting element via a
supply line, the pump is connected with the second connecting
element via a return line, and at least a first valve is arranged
in the supply line and a second valve is arranged in the return
line to separate at least one of the apparatus and the pump from
the connecting means.
18. The mobile heat exchanger cleaning system according to claim
17, comprising: a first reversal line with at least a third valve,
wherein the first reversal line connects the apparatus with the
second connecting element, and a second reversal line with at least
a fourth valve, wherein the second reversal line connects the pump
with the first connecting element.
19. The mobile heat exchanger cleaning system according to claim
14, wherein the pump comprises a control unit to adjust a volume
flow of the pump.
20. The mobile heat exchanger cleaning system according to claim
19, wherein the control unit is adapted to intermittently operate
the pump.
21. The mobile heat exchanger cleaning system according to claim
14, wherein a counting device is provided for the cleaning
bodies.
22. The mobile heat exchanger cleaning system according to claim
14, wherein a second apparatus is provided for collecting the
cleaning bodies.
23. The mobile heat exchanger cleaning system according to claim
14, wherein a filter is provided for separating out particulate
material.
24. An adapter for a heat exchanger comprising at least a first
port for connection with a heat exchanger, a second port for the
releasable connection of a heat exchanger cleaning system, and a
third port for connection with a cooling line of a cooling
circuit.
25. A heat exchanger for power plants, comprising an inlet line and
an outlet line and a plurality of tubes connecting the inlet line
with the outlet line, wherein at least one guiding element is
arranged for distributing cleaning bodies to the plurality of
tubes.
26. A method of operating a heat exchanger cleaning system
comprising providing a pump, using said pump to pump a fluid with
cleaning bodies through a heat exchanger, and operating the pump
intermittently and/or controlling the pump to achieve a variation
of a pumped volume flow in the heat exchanger.
Description
BACKGROUND
[0001] (1) Field of the Invention
[0002] The invention relates to a system for cleaning heat
exchangers, in particular power plant heat exchangers, and more
particularly, heat exchangers in the hot area of nuclear power
plants. Furthermore, the invention relates to an adapter for heat
exchangers, a heat exchanger, and a method for operating a cleaning
system for heat exchangers.
[0003] (2) Prior Art
[0004] Cleaning plants for heat exchangers are known in the state
of the art. Spherical, sponge-like cleaning bodies are injected,
for example, into the fluid flow in the inlet line of a tube-bundle
heat exchanger during normal operation. The fluid flow, for example
the cooling water, carries these cleaning bodies through the
individual tubes of the heat exchanger whereby deposits in the heat
exchanger are mechanically removed. In the outlet line of the heat
exchanger, the cleaning bodies are separated from the fluid flow by
means of a screen device after passing through the heat exchanger,
and guided into a recirculating line, either to collect them there
after a successful cleaning cycle or to reintroduce them into the
inlet line of the heat exchanger.
[0005] Such systems are not suitable, however, for all
applications. It is thus necessary on the one hand to provide an
injector in the inlet line of the heat exchanger that introduces
the cleaning bodies into the fluid flow, and on the other hand to
provide the initially described screen devices in the outlet line
of the heat exchanger allowing the cleaning bodies to be removed
from the fluid flow after passing through the heat exchanger. It is
thus necessary to make major modifications to the structure of the
heat exchanger circuit.
[0006] Such a modification has its drawbacks, however, in certain
cooling plants, for example in nuclear power plants, due to the
high safety standards. For this reason numerous heat exchangers of
cooling and refrigerating applications situated in the hot area of
nuclear power plants are not automatically cleaned during running
operation but only manually during maintenance periods.
SUMMARY OF THE INVENTION
[0007] It is thus the object of the present invention to create a
heat exchanger cleaning system, in particular for heat exchangers
in nuclear power plants, which avoids the initially mentioned
drawbacks.
[0008] The object is achieved by a mobile heat exchanger cleaning
system according to the claims. Further aspects of the invention
relate to an adapter for the heat exchanger, a heat exchanger, and
a method of operating a heat exchanger cleaning system. The
dependent claims relate to preferred embodiments of the
invention.
[0009] According to the present invention, the mobile heat
exchanger cleaning system comprises a first apparatus for
collecting, introducing and removing cleaning bodies, a pump for
pumping a fluid with cleaning bodies, and connecting means
connected with the apparatus and the pump for releasable connection
of the cleaning system to a heat exchanger.
[0010] The system according to the present invention allows safe
and reliable cleaning of power plant heat exchangers, for example,
whereby the overhead for installation and acquiring permits is
advantageously reduced. The system is mobile and can be easily
transported to various deployment locations.
[0011] Compared to the previous manual cleaning of heat exchangers
in nuclear power plants, the invention further enables the
radiation exposure of the operating personnel to be advantageously
reduced, since cleaning can be carried out almost entirely
automatically.
[0012] In the context of the present invention, a heat exchanger is
construed to mean a heat transfer means, in particular, which
transfers the thermal energy from a first medium, such as a fluid,
for example cooling water, to a further medium, such as air or
water. It goes without saying that the invention is basically
suitable for all such heat exchangers, irrespective of whether the
first medium is cooled or heated. The terminology used in the
following should thus be construed in the broader sense.
[0013] In particular, the invention is suitable for heat exchangers
in nuclear power plants, preferably for tube-bundle heat exchangers
in cooling or refrigerating plants.
[0014] A cleaning body is understood to be any kind of body that
has a cleaning effect as it passes through the respective type of
heat exchanger to be cleaned. Preferably, spherical cleaning bodies
are used, in particular preferably of a sponge-like material, such
as plastic material or foamed plastic. The cleaning bodies should
be adapted to the dimensions of the heat exchanger tubes and to the
respective medium, so that they can be transported through the heat
exchanger together with the fluid flow.
[0015] In the context of the present invention, a cooling line is
understood to be a connection line, with the aid of which the heat
exchanger is connected to a cooling circuit, such as a cooling or
refrigerating plant, in operation.
[0016] As far as a separation of individual components from each
other, such as the heat exchanger from the cooling line, is
referred to in the present invention, complete separation is not
necessary. Rather the usual leakages are possible.
[0017] As initially discussed, the system according to the present
invention comprises a first apparatus for collecting, introducing
and removing the cleaning bodies.
[0018] The apparatus can have any suitable configuration and can
have a one-part or multi-part construction. For introducing and
removing, the apparatus can have a maintenance opening, for
example, which seals the apparatus in operation, but allows removal
or introduction of the cleaning bodies.
[0019] Advantageously, the apparatus comprises a screen device to
reliably collect the cleaning bodies after completion of a cleaning
cycle, or to store them. Preferably, the screen device can be moved
or adjusted in at least one first and one second position. A
correspondingly configured motor drive, for example, can be used
for this purpose.
[0020] Particularly preferably the screen device is formed in such
a manner, that it allows collection of the cleaning bodies in the
apparatus in the first position, which will be referred to as
"collecting" or "catching operation" in the following.
[0021] Particularly preferably the screen device is configured in
such a manner that it allows introduction of the cleaning bodies
into an inlet line of the system, or into a heat exchanger
connected to the system, in a second position. The second position
of the screen device therefore corresponds to a "cleaning
operation".
[0022] The pump according to the present invention is configured
for pumping the fluid and the cleaning bodies contained therein.
The pump should be adapted to the respective hydraulic conditions
of the system and the heat exchanger, in particular with respect to
the volume flow to be pumped or the line cross-section and
pressure.
[0023] The pump should be arranged upstream of the apparatus with
respect to the flow direction, which results in favorable hydraulic
conditions for the catching operation, in particular. The pump
preferably has a frequency-controllable motor.
[0024] According to the present invention, connecting means are
also provided, which are connected with the apparatus and the pump.
The connecting means are further configured for releasable
connection of the cleaning system to the heat exchanger so that the
system can be easily and simply connected to the heat exchanger to
be cleaned. The system according to the present invention is thus
easily transportable.
[0025] In operation, a closed cleaning circuit is provided between
the apparatus, the pump and the heat exchanger by means of the
connecting means.
[0026] Preferably, the connecting means comprise a first connecting
element for releasable connection of the cleaning system with an
inlet line of the heat exchanger, and a second connecting element
for releasable connection of the cleaning system with an outlet
line of the heat exchanger.
[0027] The connecting elements can be configured as connection
flanges, such as screw or weld flanges to allow secure connection
with the heat exchanger. Alternatively, or additionally, the
connecting elements can be configured as quick-release couplings so
that simple installation is possible. Suitable quick-release
coupling systems are known according to the state of the art.
[0028] According to a preferred embodiment of the invention, the
first and/or the second connecting element comprises a connecting
tube for connection with the inlet or outlet lines of the heat
exchanger.
[0029] The connecting tube can be adapted, for example, to the
inlet or outlet lines so that the cleaning system can be releasably
connected with the heat exchanger by engaging the connecting tube
with a section of the inlet or outlet line. By these means, a
further simplified connection of the system with the heat exchanger
is enabled.
[0030] Preferably, the outer diameter of the connecting tube
essentially corresponds to the inner diameter of at least one
section of the inlet or outlet line of the heat exchanger so that a
secure connection of the cleaning system to the heat exchanger is
provided.
[0031] The connecting tube can have the form of a sleeve, or can be
conical and/or can be provided with a radially-arranged sealing
ring. However, a completely sealed connection is not absolutely
necessary for many applications.
[0032] The connecting elements can of course also have a connection
flange, or a corresponding quick-release coupling, to further
increase connection security even if configured with the above
described connecting tube.
[0033] If the heat exchanger is equipped with a connecting adapter,
as described below, the outer diameter of the connecting tube
should essentially correspond to the inner diameter of at least a
section of the respective connection piece of the adapter.
[0034] Particularly preferably, the connecting tube is configured
in such a manner that the inlet and/or the outlet lines of the heat
exchanger are essentially, i.e. excepting any leakages, separated
from a cooling line and connected to the cleaning system in the
usage position on the heat exchanger.
[0035] According to the present embodiment, the connecting elements
thus advantageously create a connection between the cleaning system
and the heat exchanger and, at the same time, separate the heat
exchanger from the cooling circuit.
[0036] While a complete separation of the heat exchanger may not be
absolutely necessary, it should be made sure that no cleaning
bodies pass into the cooling line or the cooling circuit.
[0037] Preferably, the heat exchanger cleaning system can be
connected to the heat exchanger in such a manner that, in the usage
position, the volume flow flowing through the heat exchanger
essentially corresponds to the volume flow flowing through the
system.
[0038] According to the present embodiment, the heat exchanger to
be cleaned is thus not connected to the cooling circuit during the
cleaning operation but only to the cleaning system, excepting any
leakages. The system is thus releasably connectable to the heat
exchanger for "offline cleaning".
[0039] Particularly preferably the system is configured in such a
manner that the volume flow flowing through the heat exchanger
essentially, i.e. excepting any leakages, corresponds to the volume
flow flowing through the first apparatus for collecting,
introducing and removing the cleaning bodies.
[0040] According to a preferred embodiment, the first apparatus is
connected to the connecting means, or the first connecting element,
via a supply line. The pump is connected to the connecting means or
the second connecting element, via a return line.
[0041] The lines can also be configured as hoses, for example. For
cleaning ordinary power plant heat exchangers of cooling or
refrigerating plants, the lines preferably have a diameter of
between 25 and 150 mm, preferably between 30 and 100 mm and
particularly preferably between 40 and 80 mm.
[0042] Preferably at least one valve is provided to separate the
first apparatus and/or the pump from the connecting means. In
particular, a first valve can be arranged in the supply line and/or
a second valve can be arranged in the return line. The valves can
be integrally formed, for example, with the connecting elements, to
achieve a particularly compact structural shape. Preferably the
valves can be operated, for example, by means of one or more
electric or pneumatic servomotors, via an electric or electronic
control.
[0043] According to a preferred embodiment of the invention, a
first reversal line with a third valve is provided, wherein the
first reversal line connects the supply line or the apparatus with
the second connecting element. A second reversal line with a fourth
valve is provided, wherein the second reversal line connects the
return line or the pump with the first connecting element.
[0044] The reversal lines allow the flow direction to be reversed
in the heat exchanger, in particular to free any cleaning bodies
jammed in the heat exchanger during a catching operation.
Furthermore, a respective reversal operation allows an even better
cleaning operation in cases of heavy deposits.
[0045] Preferably, the pump has a control unit to adjust the volume
flow of the pump. A volume flow variation of preferably at least
20%, also intermittently if required, should be possible. The
control unit can comprise a frequency control or closed-loop
control, to vary the rotational speed and pumping rate of the pump.
Alternatively or additionally, the control unit can comprise a pump
bypass and a respective valve to achieve an adjustment or reduction
of the pumped volume flow by hydraulically short-circuiting the
pump.
[0046] Depending on the configuration of the heat exchanger, it is
thus advantageously possible to influence the distribution of the
cleaning bodies within the heat exchanger and to adapt it to each
heat exchanger type.
[0047] Preferably the control unit is alternatively or additionally
configured in such a manner that it can operate the pump in
intermittent, for example non-continuous operation. Such operation
is also suitable to achieve a variation of the volume flow within
the heat exchanger and thus to control the distribution of the
cleaning bodies in the heat exchanger.
[0048] In the context of the present invention, an intermittent
operation of the pump means that the volume flow emitted by the
pump is temporarily varied, i.e. reduced or increased. The
variation can be in surges or pulses. A control is also possible,
i.e. a variation of the emitted volume flow with a greater time
constant that can be periodic, for example. It is useful to have a
combination of the surging or intermittent operation and the
above-described control, i.e. the variation of the volume flow.
[0049] The control unit is preferably configured in such a manner
that it operates or controls the pump in correspondence with the
dimensions and sinking velocity of the cleaning bodies in such a
manner that there is essentially a uniform distribution of the
cleaning bodies in the heat exchanger. The variation of the volume
flow thus allows varied dwell times of the cleaning bodies in the
inlet area of the heat exchanger and thus, in turn, varied
distribution profiles of the cleaning bodies in the inlet area of
the heat exchanger.
[0050] According to a preferred embodiment of the invention, a
counting device is provided for the cleaning bodies. The counting
device allows the number of cleaning bodies present in the system
or in the heat exchanger to be determined. In the catching
operation after cleaning is completed it can thus be determined,
for example, whether all cleaning bodies have been removed from the
heat exchanger and the cleaning system can thus be switched off and
separated from the heat exchanger.
[0051] The counting device can have a one or multi-part
configuration and comprise mechanical determination means, for
example, such as a counting wheel. Preferably the counting device
comprises at least one light barrier enabling a particularly
reliable counting operation.
[0052] The counting device can be arranged in the supply and/or
return line to count the cleaning bodies passing through the supply
and/or return lines. Alternatively or additionally the counting
device can be arranged between the pump and the first
apparatus.
[0053] Preferably, a supply apparatus is upstream of the counting
device to supply the cleaning bodies in an individual or defined
manner to the counting device. The precise configuration of the
supply apparatus should be adapted to each type of counting
device.
[0054] The supply apparatus can preferably comprise a screen that
is moveable or pivotable into at least a first and a second
position. In the first position, the screen is for supplying the
cleaning bodies individually or in a defined manner to the counting
device. In the second position, the screen is preferably pivoted in
such a manner that it allows cleaning of the screen, for example,
by means of backwashing.
[0055] According to a preferred embodiment of the invention, a
second apparatus is provided for collecting the cleaning bodies.
The second apparatus is preferably arranged between the first
apparatus and the pump for temporarily storing or collecting the
cleaning bodies in the catching operation.
[0056] Preferably, the second apparatus is arranged such that, in
the usage position, the volume flow flowing through the heat
exchanger essentially, i.e. excepting any leakages, corresponds to
the volume flow flowing through the second apparatus.
[0057] Particularly preferably, the second apparatus can comprise a
screen device movable at least into a first and a second position.
The screen device can be configured in such a manner that it allows
collecting of the cleaning bodies in the second apparatus in its
first position.
[0058] Alternatively or additionally the second apparatus can be
configured in such a manner that it supplies cleaning bodies to the
counting device in its first position. In this way, for example,
after completion of the cleaning operation, it is possible to check
whether all cleaning bodies have been removed from the heat
exchanger or whether further measures, such as the initially
discussed reversal operation or an intermittent, i.e., for example,
surging operation of the pump is necessary to free the cleaning
bodies remaining in the heat exchanger.
[0059] Preferably, the screen device of the second apparatus is
configured in such a manner that it allows the cleaning bodies to
be supplied to the counting device in the first position and to the
first apparatus and/or the supply line in the second position.
[0060] According to an embodiment of the invention, a filter or
filter unit for separating out contaminant particles is arranged,
for example, between the pump and the first apparatus. The filter
should be adapted to each medium and the contamination to be
expected. The filter is preferably a particle filter.
[0061] Preferably the filter is arranged in a filtration line
arranged parallel to the first and/or second apparatus.
Particularly preferably at least one valve arrangement is provided
to guide fluid at least partially through the filtration line
and/or the first or second apparatus in the usage position.
[0062] For use of the cleaning system according to the present
invention it is desirable to simply connect the cleaning system to
the heat exchanger as initially described.
[0063] A second aspect of the present invention thus relates to an
adapter for a heat exchanger, in particular a power plant heat
exchanger. The adapter has at least a first port for connecting it
with the heat exchanger, a second port for releasably connecting a
heat exchanger cleaning system, and a third port to connect it to a
cooling line, for example a cooling circuit of a cooling or
refrigerating plant.
[0064] The adapter according to the present aspect permits simple
retrofitting of existing heat exchangers so that a cleaning system,
for example according to the above described embodiments, can be
easily and quickly connected to a heat exchanger. Particularly
present heat exchangers can thus be simply operated with the above
described cleaning system.
[0065] To establish a releasable connection to a cleaning system,
the second port can be configured with a connection flange for
connecting it with a corresponding connecting element, such as a
screw or weld flange or a quick-release coupling.
[0066] It goes without saying that the first port can serve to
establish a connection with an inlet and/or outlet line of the heat
exchanger. It is of course also conceivable that the adapter is
integrally formed with the heat exchanger.
[0067] Preferably two adapters are provided, namely a first adapter
for connecting the inlet line of the heat exchanger with a supply
line of the cleaning system, and a second adapter for connecting an
outlet line of the heat exchanger with a return line of the
cleaning system.
[0068] The adapter can also preferably be provided with a fourth
port, as the case may be, to connect further heat exchangers with
the cooling line. In particular, the first and the fourth port can
be configured for a so-called header line that connects a plurality
of heat exchangers in the cooling circuit.
[0069] Preferably, means for flow control are provided to connect
the heat exchanger either with the cleaning system or the second
port, or the cooling line or the third port.
[0070] The initially discussed means for flow control can feature
all suitable configurations to connect the heat exchanger either
with the second or the third port. It is thus ensured that the heat
exchanger, in the operating condition, is either connected to the
cooling circuit or, during cleaning, to the cleaning system. Even
though complete separation from the respective other connection is
desirable, it is sufficient if the means is configured in such a
manner that no cleaning bodies of the cleaning system enter into
the cooling circuit. Smaller leakages into the cooling circuit, in
particular during the established connection of the cleaning
system, are thus by all means possible.
[0071] Preferably, the means are switchable from a first position
to a second position to connect the first port either with the
second or the third port. Preferably the means comprise at least
one switchable valve.
[0072] Alternatively or additionally, the adapter has a connecting
portion with at least one section having an inner diameter
essentially corresponding to the outer diameter of a connecting
tube of a cleaning system to be connected by means of the adapter.
Preferably, the section is configured in such a manner that when
the connecting tube of the cleaning system is connected, the first
port is separated from the third port, i.e. excepting any
leakages.
[0073] For this purpose the adapter can be configured, for example,
with a first conduit at which the first and second ports face each
other. A second conduit or header tube extends perpendicular to the
first conduit and is connected to the latter in the area between
the first and second ports. The second conduit has the third and
fourth port, as the case may be, at its end. The inner diameter of
the first conduit preferably essentially corresponds to the outer
diameter of the connecting tube.
[0074] The connecting tube in this case can be inserted into the
first conduit by means of the second port in such a manner that the
second conduit is bridged or covered by the connecting tube. The
heat exchanger is then only connected to the cleaning system.
[0075] The above described adapter is suitable, in particular, in
combination with the initially described mobile heat exchanger
cleaning system.
[0076] According to a further independent aspect of the present
invention, a heat exchanger, in particular for power plants, is
provided with an inlet line, an outlet line and a plurality of
tubes. The tubes connect the inlet line with the outlet line. At
least one guiding element is provided for distributing cleaning
bodies to the plurality of tubes.
[0077] The guiding element ensures improved distribution of the
cleaning bodies in the heat exchanger, in particular in a
tube-bundle heat exchanger in cooling or refrigerating plants. An
irregular distribution of the cleaning bodies in the individual
tubes causing a reduction of performance is thus advantageously
avoided.
[0078] The guiding element can have any number of suitable
configurations; preferably, the guiding element is configured as a
guiding grid or guiding plate. Alternatively or additionally, the
guiding element can have an impacting element ensuring a largely
random distribution of the cleaning bodies.
[0079] If the inlet line and/or the outlet line is connected to the
tubes via at least one tube manifold, the guiding element should
preferably be arranged in the tube manifold.
[0080] The above-discussed heat exchanger is particularly
advantageous in combination with the inventive mobile heat
exchanger cleaning system, or the above-discussed adapter.
[0081] A further independent aspect of the present invention
relates to a method of operating a heat exchanger cleaning system,
mobile as the case may be, with a pump for pumping a fluid with
cleaning bodies through a heat exchanger. Herein, the pump is
operated intermittently and/or controlled according to the present
aspect in order to achieve a variation of the pumped volume flow in
the heat exchanger.
[0082] The present method allows for improved distribution of the
cleaning bodies in the heat exchanger, but advantageously without
structural modifications of the existing plants. Furthermore, the
method allows for the removal of any cleaning bodies stuck during
cleaning in the heat exchanger, in a catching operation.
[0083] In the context of the present aspect, an intermitting
operation of the pump means that the volume flow pumped by the pump
is temporarily varied, i.e. reduced or increased. Herein, the
variation can be in surges or pulses. However, a control is also
possible, i.e. a variation of the emitted volume flow with a
greater time constant, such as for example in a periodic manner.
Preferably the operation in surges or pulses and the above
mentioned control, i.e. the variation of the volume flow, is
combined.
[0084] Preferably, the pump is intermittently operated between at
least one first and one second operating state, wherein the emitted
volume flow differs by at least 20% between the first and second
operating condition, i.e. the volume flow variation is at least
20%.
[0085] Depending on the dimensioning and the sinking velocity of
the cleaning bodies, the pump can be preferably operated or
controlled in such a manner that an essentially uniform
distribution of the cleaning bodies is provided in the heat
exchanger. This is because, by varying the volume flow, different
dwell times of the cleaning bodies in the inlet area of the heat
exchanger and thus, in turn, varied distribution profiles of the
cleaning bodies in the inlet area of the heat exchanger are
possible.
[0086] To achieve this, the above described intermittent operation
can be used, for example. Alternatively or additionally, it is also
conceivable to adjust the pumping rate of the pump in such a manner
that the cleaning bodies can sink in the inlet area of the heat
exchanger and are thus advantageously distributed in the heat
exchanger.
BRIEF DESCRIPTION OF THE DRAWINGS
[0087] The invention will be explained in the following with
reference to exemplary embodiments. In the drawings:
[0088] FIG. 1a shows a first exemplary embodiment of a cleaning
system in a schematic view,
[0089] FIG. 1b shows the exemplary embodiment of FIG. 1a with a
connected heat exchanger;
[0090] FIG. 2 shows a second exemplary embodiment of a cleaning
system in a schematic view;
[0091] FIG. 3 shows a third exemplary embodiment of a cleaning
system in a schematic view;
[0092] FIG. 4 shows a fourth exemplary embodiment of a cleaning
system in a schematic view;
[0093] FIG. 5 shows a fifth exemplary embodiment of a cleaning
system in a schematic view;
[0094] FIG. 6 shows a sixth exemplary embodiment of a cleaning
system in a schematic view;
[0095] FIG. 7a is a schematic view of an exemplary embodiment of a
heat exchanger in a first sectional view;
[0096] FIG. 7b shows the exemplary embodiment according to FIG. 7a
in a second sectional view;
[0097] FIG. 8a is a schematic view of an exemplary embodiment of an
adapter for a heat exchanger in a first sectional view;
[0098] FIG. 8b is a schematic view of the exemplary embodiment
according to FIG. 8a in a second sectional view;
[0099] FIG. 9a is a schematic view of a second exemplary embodiment
of an adapter for a heat exchanger in a first sectional view;
and
[0100] FIG. 9b is a schematic view of the exemplary embodiment
according to FIG. 9a in a second sectional view.
[0101] FIG. 1a shows a first exemplary embodiment of the cleaning
system 10 according to the present invention in a schematic
view.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0102] The cleaning system comprises an apparatus 1 which collects
or receives the cleaning bodies (not shown) and enables the
introduction or removal of these. To achieve this, collection
apparatus 1 can have a maintenance opening, for example, which
seals apparatus 1 in operation with respect to the environment, but
which enables removal or introduction of the cleaning bodies for
maintenance purposes. The cleaning bodies in the present example
are configured as cleaning spheres of plastic or foamed plastic,
wherein they should of course be adapted to the respective cleaning
task.
[0103] Apparatus 1 has a pivotable screen device 7 allowing the
cleaning operation to be controlled as will be explained in detail
in the following. Screen device 7 is driven by means of an
associated motor 9 and can thus be pivoted from a first position
into at least a second position. Similarly, alternatively or
additionally, manual operation is also possible. In the first
position shown, which corresponds to the so-called "catching
operation", the cleaning bodies are retained in apparatus 1, while
in the second position (not shown), which corresponds to a cleaning
operation, the cleaning bodies are released into a supply line
14a.
[0104] Cleaning system 10 further comprises a pump 2, which is
connected to apparatus 1 via a respective tube and, as shown in
FIG. 1a, is arranged upstream of apparatus 1 as seen in the flow
direction. Pump 2 comprises a motor which, if it has a
frequency-controllable configuration, can achieve a rotational
speed variation and thus adapt the volume flow pumped by pump
2.
[0105] Cleaning system 10 further comprises connecting means for a
releasable connection with a heat exchanger. As shown in FIG. 1a,
for example, first connecting element 8a and a second connecting
element 8b can be provided, which are connected to pump 2 and
apparatus 1 via supply line 14a and return line 14b in a
corresponding manner. Lines 14a and 14b are configured as hoses,
for example, in the present case having a diameter of 80 mm. Lines
14a and 14b can of course also have different configurations or
dimensions, and are adapted, in particular, to the heat exchanger
to be cleaned.
[0106] Connecting elements 8a and 8b are configured as a
screw-connectable port flange in the present case and enable a
releasable connection of cleaning system 10 with the heat exchanger
to be cleaned. Connecting elements 8a and 8b can also have other
configurations, but connecting elements 8a and 8b should enable
secure connection with the heat exchanger to be cleaned or a
corresponding connecting adapter, as will be explained in the
following. Connecting elements 8a and 8b can also be configured as
quick-release couplings or quick-release locks to further simplify
handling. Two valves 3 and 4 are provided to separate apparatus 1
and pump 2 from connecting elements 8a and 8b as needed.
[0107] Cleaning system 10 according to FIG. 1a has a mobile
configuration so that the plant can be easily transported to the
heat exchanger in question. For this purpose, pump 2 and apparatus
1 are mounted on a mobile base frame or chassis (not shown). System
10 can thus be used in various manners so that only one cleaning
system 10 is necessary for a plurality of heat exchangers such as
is the case in a power plant. For this reason the investment
necessary can be substantially lowered as compared to known fixedly
installed systems.
[0108] FIG. 1b shows cleaning system 10 according to FIG. 1a in the
usage position on a respective heat exchanger 11. The latter is a
tube-bundle heat exchanger with about 500 individual tubes. Heat
exchanger 11 has an inlet line 12 which, in normal cooling
operation, is linked to a first cooling line 15a of the cooling
circuit (not shown), for example, a cooling or refrigerating plant
of a nuclear power plant. The cooling circuit is operated with
process water in the present case, however, other fluids are also
conceivable.
[0109] Inlet line 12 opens out into an inlet-side tube manifold 41
communicating with an outlet-side tube manifold 42 via the
individual tubes. Outlet-side tube manifold 42, in turn, is linked
to a second cooling line 15b of the cooling circuit via an outlet
line 13. The present cleaning system 10 is of course also suitable
for cleaning heat exchangers 11 having a different structure.
Similarly, the cooling circuit can have further heat exchangers 11
as the case may be, depending on its dimensioning.
[0110] For cleaning heat exchanger 11, cleaning system 10 is first
connected to inlet line 12 and outlet line 13 of heat exchanger 11.
As shown in FIG. 1b, joint elements 16a and 16b are provided for
connection with connecting elements 8a and 8b in order to connect
cleaning system 10 with heat exchanger 11. Joint elements 16a and
16b are configured as a flange in correspondence with connecting
elements 8a and 8b in order to create a secure connection.
[0111] Four valves 3, 4, 5, 6 are provided overall to separate heat
exchanger 11 from cooling lines 15a and 15b and thus from the
cooling circuit and to connect them with supply line 14a and return
line 14b of cleaning system 10 and thus with the cleaning circuit.
After opening valves 3 and 4, cleaning system 10 is connected with
inlet line 12 and outlet line 13 of heat exchanger 11. In contrast
to hitherto known systems, heat exchanger 11 is thus only connected
with the cleaning circuit during the cleaning operation, i.e. the
cleaning system 10 and no longer with the cooling circuit, which
will also be referred to as an "offline operation" in the
following. The volume flow flowing through heat exchanger 11 is
thus essentially, i.e. excepting any leakages, guided through
system 10, or apparatus 1, whereby the screens provided in prior
systems for separating a partial flow of the fluid and cleaning
bodies contained therein is advantageously avoided. System 10 is
thus extremely cost-effective.
[0112] For the cleaning process, system 10 is first filled with
water, for example from the cooling circuit. Subsequently, pump 2
is activated and screen 7 of apparatus 1 is brought into the second
position (not shown) so that the cleaning bodies pass through
supply line 14a and inlet line 12 into the individual tubes of heat
exchanger 11 to remove deposits or sediment therein. The cleaning
bodies subsequently pass through outlet line 13 and return line 14b
to pump 2 and are returned to apparatus 1 in a corresponding
manner.
[0113] With screen device 7 in an open position a continuous
cleaning operation is provided, which can be carried out fully
automatically as the case may be. System 10 thus only requires
little personnel overhead for connection of system 10, while
operation is largely automatic. This is advantageous, in
particular, in security areas, for example of nuclear power plants,
since the radiation exposure of personnel is thereby lowered by a
substantial degree.
[0114] After the cleaning process is completed, screen device 7 is
moved into the closed, first position by servomotor 9 so that the
cleaning bodies are collected in apparatus 1. Subsequently, valves
3 and 4 are closed, valves 5 and 6 are opened, whereby the heat
exchanger is connected to the cooling circuit again.
[0115] Cleaning system 10 can then be separated from heat exchanger
11 and used, for example, for cleaning a further heat exchanger 11.
The plant is thus extremely flexible.
[0116] Preferably, system 10 comprises an electronic control unit
(not shown) for controlling the individual components, in
particular pump 2 and apparatus 1, so that the cleaning operation
is automatically carried out. The control unit can be configured,
for example, as a microprocessor or SPS control, which, in
combination with respective programming controls the cleaning
operation.
[0117] It has been shown that it is absolutely necessary that the
cleaning bodies are completely removed from heat exchanger 11 after
completion of the cleaning operation. In particular, blocking of
the tubes of heat exchanger 11 by any remaining cleaning bodies
must be avoided.
[0118] FIG. 2 thus shows a second exemplary embodiment of the heat
exchanger cleaning system 10' according to the present invention
which, in the usage position as seen in FIG. 1b is shown connected
to a heat exchanger 11.
[0119] System 10' largely corresponds to system 10 explained with
reference to FIGS. 1a and 1b, wherein a first reversal line 17a and
a second reversal line 17b are provided allowing fluid to pass
through the heat exchanger 11 in a direction reversed with respect
to FIG. 1b. First reversal line 17a connects supply line 14a with
second connecting element 8b via a valve 18a. Second reversal line
17b connects return line 14b with first connecting element 8a via a
further valve 18b. To reverse the flow direction, valves 3 and 4
are closed and subsequently valves 18a and 18b are opened, whereby
the fluid is now supplied to heat exchanger 11 through outlet line
13.
[0120] It has been shown that the reversal of the flow direction
advantageously enables any remaining cleaning bodies in the heat
exchanger 11 to be released so that after completion of the
cleaning process they can be collected in apparatus 1, as initially
explained with reference to FIG. 1b.
[0121] Furthermore, the configuration of the cleaning system 10'
according to FIG. 2 also allows an improved cleaning operation in
the case of heavy deposits by reversing the flow direction during
the cleaning process.
[0122] FIG. 3 shows a third exemplary embodiment of the heat
exchanger cleaning system 10'' according to the present invention
which, in the usage position as shown in FIG. 1b, is shown
connected to a heat exchanger 11.
[0123] According to FIG. 3, a further apparatus 20 is provided that
is arranged between pump 2 and first apparatus 1. Second apparatus
20, just like first apparatus 1, comprises a pivotable screen
device 7 for temporarily collecting the cleaning bodies, but also
for supplying them to a counting device 19.
[0124] Counting device 19 enables the number of cleaning bodies to
be determined, which pass from heat exchanger 11 back into cleaning
system 10'', for example, after the cleaning process. It can thus
be determined, for example, whether the cleaning bodies have been
completely removed from heat exchanger 11 after completion of the
cleaning process.
[0125] During the cleaning operation, screen device 7 is also moved
into the second, opened position (not shown) as discussed with
reference to first apparatus 1. In the second position, screen
device 7 allows unhindered passage of the cleaning bodies through
second apparatus 20. A shutter 21 takes care of adjusting the
volume flow in the line between second apparatus 20 and first
apparatus 1.
[0126] After completion of the cleaning operation, both screen
devices 7 of first apparatus 1 and second apparatus 20 are moved
into the first, closed position for collecting the cleaning bodies
in first apparatus 1.
[0127] The cleaning bodies are now temporarily collected in second
apparatus 20 and supplied to a bypass line 22 by opening valve 23,
which connects second apparatus 20 with first apparatus 1 via
counting device 19.
[0128] The number of cleaning bodies is now determined by means of
counting device 19. Hereafter, the cleaning bodies pass into first
apparatus 1 and are stored there for another cleaning cycle. As
soon as the overall number of the cleaning bodies contained in
system 10'' has been determined by counting device 19, pump 2 is
switched off and valves 3-6 are controlled as initially discussed.
System 10'' can now be separated from heat exchanger 11.
[0129] Counting device 19 is also connected with the initially
mentioned control unit, which is not shown in FIG. 3, however, for
clarity. Counting device 19 comprises a light barrier in the
present case to reliably detect the cleaning bodies. Counting
device 19 can also have a different configuration, however,
depending on the respective nature of the cleaning bodies, it is
thus also conceivable, for example, to provide a camera to detect
the cleaning bodies. Alternatively or additionally other counting
devices, such as mechanical or electrical, could also be used.
[0130] An alternative exemplary embodiment of a cleaning system
10''' with counting device 19 is shown in FIG. 4. System 10'''
largely corresponds to system 10'' discussed with reference to FIG.
3, wherein counting device 19 is directly arranged in the line
between pump 2 and apparatus 1. A batch operation is thus
advantageously enabled.
[0131] Counting device 19 has an integral configuration with an
associated supply apparatus 24, which ensures a defined supply of
the cleaning bodies into counting device 19 so that it is possible
to reliably detect the cleaning bodies. For this purpose supply
apparatus 24 has a pivotable screen 25 forming an inlet funnel in
the illustrated first position, to guide the cleaning bodies in the
upper area of supply apparatus 24 individually past counting device
19. In a second position (not shown) screen 25 can be washed
backwards and thus cleaned of deposits.
[0132] FIG. 5 shows a fifth exemplary embodiment of a cleaning
system 10'''' according to the present invention which largely
corresponds to cleaning system 10 discussed with reference to FIG.
1b, wherein, however, a filter 26 is arranged in a filtration line
27.
[0133] Filter 27 is configured as a particle filter in order to
separate particulate from fluid. By closing a valve 28a and opening
a valve 28b, filtration of the fluid can be carried out prior to
and/or after the cleaning operation to remove any dissolved
particulate. It should be ensured, of course, that all cleaning
bodies are within apparatus 1.
[0134] As initially mentioned, filter 26 is configured as a
particle filter. For this purpose, filter 26 can comprise suitable
filter media, for example, which are adapted to the relative
filtration degree. For the usual plants, filter 26 can be
preferably adapted to a particle size of 50-500 .mu.m. Filter 26
can of course also be variably adapted to each application.
[0135] As initially explained with reference to FIG. 2, any
cleaning bodies remaining in heat exchanger 11 can be released by
reversing the flow direction within heat exchanger 11.
[0136] Alternatively or additionally it is also possible to operate
the pump 2 in an intermittent, for example surge-like fashion to
release any jammed cleaning bodies. A further, independent aspect
of the invention thus relates to a method for operating a heat
exchanger cleaning system.
[0137] An intermittent operation of pump 2 means that the volume
flow pumped by pump 2 is temporarily varied, i.e. reduced or
increased. It can be advantageous, for example, to operate pump 2
in two alternating modes of operation. The precise volume flow
should be chosen, however, depending on each application.
[0138] For an intermittent operation, the rotational speed of pump
2 can be correspondingly varied by the control unit.
[0139] Alternatively or additionally, pump 2 can be temporarily
short-circuited through a pump bypass 30 and an associated valve 29
to achieve a corresponding reduction of the volume flow as shown in
a further exemplary embodiment of heat exchanger cleaning system
10''''' according to FIG. 6.
[0140] Such an embodiment of the system has a further advantage
when tube-bundle heat exchangers in cooling or refrigerating plants
are cleaned. Due to the relatively small dimensions there is a
problem in the tube manifolds of such heat exchangers that the
cleaning bodies may not be uniformly distributed throughout the
individual tubes of the heat exchanger.
[0141] By intermittently operating pump 2 during the cleaning
operation, i.e. by preferably controlling the pumped volume flow,
an improvement can be achieved in the distribution of the cleaning
bodies throughout the tubes of the heat exchanger.
[0142] This is the case, in particular, if depending on the
dimensioning and sinking velocity of the cleaning bodies the pump
is operated during the cleaning operation in such a manner that the
cleaning bodies sink within the tube manifold of the heat exchanger
in a controlled manner and are thus uniformly distributed
throughout the individual tubes. Again, the rotational speed of
pump 2 can be appropriately varied by the control unit.
Alternatively or additionally, an intermittent operation of pump 2
during the cleaning process can also be achieved by the embodiment
of system 10 shown in FIG. 6.
[0143] For better distribution of the cleaning bodies within heat
exchanger 11 it is also conceivable to provide mechanical means for
guiding the cleaning bodies in heat exchanger 11. A further,
independent aspect of the invention thus relates to an improved
heat exchanger.
[0144] FIG. 7a shows an exemplary embodiment of a heat exchanger
11' in a schematic sectional view.
[0145] Heat exchanger 11' comprises an inlet line 12 opening out
into an inlet-side tube manifold 41. Tube manifold 41 connects
inlet line 12 with individual tubes 60 of heat exchanger 11'. For
reasons of clarity, the outlet side of heat exchanger 11' is not
shown in FIG. 7a.
[0146] A guiding element 61 extends from inlet line 12 into tube
manifold 41. Guiding element 61 is a guiding plate in the present
case for guiding the cleaning bodies introduced into heat exchanger
11' during the cleaning process through inlet line 12, also to
tubes 60 remote from inlet line 12. To achieve this, guiding
element 61 extends to about two thirds of the overall length of
tube manifold 41 as can also be seen from FIG. 7b, in particular.
FIG. 7b shows the exemplary embodiment of heat exchanger 11' in a
further sectional view along line A-A'.
[0147] Even though FIGS. 7a and 7b only show guiding element 61 in
inlet-side tube manifold 41, it is also conceivable, of course,
alternatively or additionally to arrange a corresponding guiding
element 61 in further tube manifolds, for example, in outlet-side
tube manifold 42 (cf. FIG. 1b) of heat exchanger 11'.
[0148] Alternatively to an embodiment of guiding element 61 as a
guiding plate, guiding element 61 can also be configured as a
guiding grid. Alternatively or additionally, guiding element 61 can
also comprise an impacting element on which the cleaning bodies
impact as they enter into line 12 and/or into tube manifold 41 and
are thus distributed throughout tubes 60.
[0149] A further independent aspect of the present invention
relates to an adapter for releasably connecting a heat exchanger
cleaning system with a heat exchanger. A first exemplary embodiment
of such an adapter 50 is shown in FIG. 8a in the first sectional
view in the usage position, i.e. with a connected heat exchanger 11
and cleaning system 10.
[0150] Adapter 50 is suitable, in particular, for retrofitting
existing heat exchangers 11 so that the initially described heat
exchanger cleaning system 10 can be easily connected with heat
exchanger 11. It is thus possible to connect a mobile cleaning
system 10 easily with heat exchanger 11, which avoids, in
particular, the overhead of acquiring permits otherwise necessary
for fixed installations, and cleaning of several heat exchangers 11
with only one cleaning system 10 is advantageously possible.
[0151] As shown in FIG. 8a, adapter 50 comprises a first port 53
for connection with a heat exchanger 11. In the present example,
first port 53 is configured as a flange and connected with inlet
line 12 of heat exchanger 11. Alternatively, first port 53 can be
welded, as the case may be, to inlet line 12 of heat exchanger
11.
[0152] A second port 54 is arranged on an opposite end of a first
conduit 58, having a joint element 16a for the releasable
connection with a connecting element 8a of a heat exchanger
cleaning system 10. For reasons of clarity, only connecting element
8a of cleaning system 10 is shown. Joint element 16a is also
configured as a flange in the present case, wherein, again,
different embodiments, such as a quick-release coupling or a
quick-release lock are also conceivable.
[0153] A third port 55 is connected with a cooling circuit (not
shown). A fourth port 56 enables the optional connection of adapter
50 with further heat exchangers 11 or further adapters 50 (not
shown), which is advantageous, in particular, with larger cooling
plants. Adapter 50 can of course also be configured without fourth
port 56. As shown, third port 55 and fourth port 56 are connected
via a second conduit 59 vertical to first conduit 58.
[0154] Two valves 57 are arranged to control the flow within
adapter 50. In normal operation, valves 57 are open, whereby heat
exchanger 11 is connected to the cooling circuit. Joint element 16a
is closed by means of a blind cover (not shown).
[0155] Valves 57 are closed for the cleaning operation, which
corresponds to the position as shown in FIG. 8a. Heat exchanger 11
is now separated from the cooling circuit and is connected to
cleaning system 10 after connection of connecting element 8a. After
the completion of the cleaning process, connecting element 8a is
separated from adapter 50 and joint element 16a is closed by the
blind cover. After opening valves 57, heat exchanger 11 is
connected with the cooling circuit again.
[0156] A corresponding adapter 50 can, of course, also be provided
at outlet line 13 of heat exchanger 11, as can be seen, in
particular, from FIG. 8b, which is a second sectional view along
line A-A'. As shown in FIG. 8b, an adapter 50 is arranged both at
inlet line 12 and at outlet line 13 of heat exchanger 11.
[0157] FIGS. 9a and 9b show an alternative exemplary embodiment of
an adapter 50' corresponding to the views of FIGS. 8a and 8b.
[0158] Adapter 50' largely corresponds to adapter 50 discussed with
reference to FIGS. 8a and 8b, wherein, in the present case, valve
57 is dispensed with. As explained above with reference to FIGS. 8a
and 8b, connecting element 8a' is also connected with joint element
16a of adapter 50' in the present case. A connecting tube 52
extends axially from the flange of connecting element 8a', in the
usage position shown, into a tube section 51 of adapter 50'.
Connecting tube 52 covers second conduit 59 and thus bridges third
port 55 and fourth port 56.
[0159] In the present case, heat exchanger 11 is separated from the
cooling circuit by the cooperation of tube section 51 of adapter
50' with connecting tube 52 of connecting element 8a' of cleaning
system 10 for the cleaning operation. The inner diameter of tube
section 51 in the present case corresponds essentially to the outer
diameter of connecting tube 52.
[0160] For example a suitable sealing element (not shown) or a
sealing ring can be used in the present case, to achieve complete
separation of the cleaning circuit from the cooling circuit.
Complete sealing can be dispensed with, as the case may be,
however, as long as it is ensured that no cleaning bodies are
introduced into the cooling circuit. FIG. 9b shows two adapters 50'
connecting inlet line 12 of heat exchanger 11 with connecting
element 8a' and, similarly, outlet line 13 with connecting element
8b' of cleaning system 10.
[0161] The heat exchanger cleaning system according to the present
invention, a heat exchanger, and an adapter for connecting a heat
exchanger cleaning system have been described above with reference
to exemplary embodiments. It is of course easily possible to
combine the exemplary embodiments shown or individual aspects of
the respective exemplary embodiments with each other.
* * * * *