10
ITEM
A-03-343
DATED
NOVEMBER 2012
SUPERCEDES
MARCH 2011
CLEANING THE HEAT EXCHANGER.
CLEANING THE PLATES OF THE CLOSED PLATE HEAT
EXCHANGER. Deposits on the heat exchanger plates impair
the heat transfer between the media, increase the pressure
loss and can cause or accelerate heat exchanger plate corrosion.
Exactly whether it needs to be done, how often it needs to be
done, and how it is done depends on the individual application.
Following are notes regarding the various standard cleaning
practices.
CIP (Clean-In-Place) Process. In the case of CIP, a
cleaning agent instead of the flow media flows through the
heat exchanger. Contaminants are removed by the cleaning
solution’s dissolving function, supported by the mechanical
action of the turbulence.
Danger to persons and environment!
The use of aggressive cleaning agents introduces risks to the
operator of poisoning, chemical burns, and burning. Make sure
that:
• Before the CIP process, you have been instructed in the use
and have a good understanding of all work steps.
• During work with aggressive cleaning agents you always
wear suitable protective clothing.
• The cleaning agent you use is completely removed from the
heat exchanger after cleaning.
Backflushing. This process is used if the flow media contain
coarse particles of contamination and thus block the inlet
channels. By briefly reversing the direction of flow, the
clogging particles are removed from the heat exchanger.
The direction of flow is reversed by using a suitable pipe
configuration with the appropriate valves. If there is a risk of
the released particles of contamination causing damage to the
heat exchanger, preference should be given to manual cleaning
of the heat exchanger plates.
CLEANING THE PLATES OF THE OPENED PLATE
HEAT EXCHANGER. Cleaning the heat exchanger plates
manually. This process is more labor-intensive than CIP or
backflushing, but works very well with buildup that is relatively
easy to remove, and gives the operator an opportunity to
visually inspect all plates.
Carry out the following work steps:
1. For severe buildup, use a high pressure cleaner nozzle first
to remove the particles.
2. Wash each plate from both sides with flowing, warm water
and a soft brush.
Cleaning the heat exchanger plates chemically. This process
works best for buildup that resists manual removal, and also
gives the operator an opportunity to visually examine all plates.
Observe the following points:
1. Always follow the safety instructions and recommendations
of the cleaning agent manufacturer. Use only chloride-free
or low-chloride water with a low hardness value for the
cleaning liquid.
2. Chlorides in the cleaning agent reduce the corrosion
resistance of chrome-nickel steels and chrome-nickel-
molybdenum steels (including Hastelloy
®
, Incoloy
®
and
Inconel
®
). The intensity of the effect of the chlorides
depends on the temperature, concentration and pH of the
medium.
3. Stubborn contamination, such as coatings on the plate
surface, which are not released by the above-described
processes, can be loosened by soaking in an open chemical
bath.
4. Choose a cleaning agent suitable for the type of buildup and
for the properties of the heat exchanger plates and gasket
materials.
a. A confirmation by the manufacturer of the cleaning agent
should be available, stating that the agent does not affect
the plate and gasket materials used in the heat exchanger.
b. Clean the heat exchanger plates according to the work
instructions of the cleaning product manufacturer.
5. Before reassembling the cleaned heat exchanger plates,
always rinse them with sufficient clean water. Remove
foreign matter on the gaskets with a soft brush.
CAUTION
Danger:
Damage to the Heat Exchanger!
The improper use of CIP can damage the heat exchanger.
• Observe the notes for chemically cleaning the heat
exchanger plates in the section “Cleaning the Plates of
the Opened Plate Heat Exchanger”.
Danger:
Leakage
Hard cleaning tools (e.g. brushes with metal bristles) can
damage the surface of the heat exchanger plates and the
surface of the gaskets. Damaged metal surfaces can lead
to rapid corrosion of the heat exchanger plates. Damaged
gasket surfaces can cause leaks when it is recommissioned.
1. Never use hard cleaning tools.
2. At every cleaning, ensure that no particles can settle on
or under the gaskets, because this leads to leaks.
3. Ensure that the stream of a high-pressure jet always
directs face-on at the gaskets in order to avoid loosening
them.
Danger:
Leakage
Chemical cleaning processes can attack the gasket material
and create leaks.
1. Always use cleaning agents that do not attack the gasket
material.
2. Choose a suitable temperature and do not expose the
gaskets to the cleaning agent for an unnecessarily long
time.
