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Paraflow Plate Heat Exchanger
Instruction Manual
Section 7.0 Issue 5
Page 30 of 36 June 13, 2008
reputable supplier of cleaning materials be consulted
for assistance. The capacities and resistance to
corrosion of plate heat exchangers depend on the
plate pack being kept clean.
Example of CIP-cleaning:
•
Drain off product residues and cooling and heating
media.
•
Rinse with cold or lukewarm water.
•
Circulate with warm cleaning fluid solution.
•
Rinse with warm water. Rinse with warm water
with softener added to it.
•
Rinse with cold or lukewarm water.
Cleaning can also be effected without circulation by
pouring a cleaning fluid solution into the system.
After some time of standing, wash out the detergent
with clean water.
7.3.1 Determination of correct CIP regime.
The plate heat exchanger must be opened for
inspection at regular intervals. This is necessary
especially during the running-in period, until
experience has been gained on the effectiveness of
the cleaning process.
With these inspections, it will gradually be possible to
determine circulation times, temperatures, and
chemical concentrations with great certainty!
Insufficient cleaning is most often due to:
•
too small circulation quantity
•
too short cleaning period.
•
too small chemical consumption in relation
•
to the fouling on the plates.
•
too long periods of operation.
If the plate heat exchanger is out of operation for a
long time, it is advisable to empty it, separate the
plates, and clean the unit.
Clamp the plate heat exchanger lightly together, and
leave it covered in order to protect the gaskets against
dirt and the effect of light!
7.3.2 Acceptable CIP solutions.
The definition of an acceptable CIP solution is brief
and to the point. Fouling on the plates must be
removed without damaging plates and gaskets or
reducing the inherent corrosion resistance. It is
important not to decompose the passive (protective)
film on stainless steel - the film contributes to
preserving the resistance of the steel to corrosion.
Do not use chlorine-containing agents such as
hydrochloric acid (HCI).
EXAMPLE OF AN ACCEPTABLE CIP SOLUTION:
(Basis Stainless 316 plates and Nitrile gaskets in Dairy
applications.)
•
OIL AND FATS are removed with a water
emulsifying oil solvent, e.g. BP-SYSTEM
CLEANER.
•
ORGANIC AND GREASY COATINGS are
removed with SODIUM HYDROXIDE (NaOH) –
Typical concentration 1.5% w/w max.
temperature 85°C (185-F). 1.5% w/w
concentration corresponds to 3.75 litre 30% NaOH
per 100 litre water.
•
MINERAL SCALE DEPOSITS are removed with
NITRIC ACID (HN0
3
)-max. concentration 1.0%
w/w - max. temperature 65°C (149°F).
1.0 % w/w concentration corresponds to 1.17 litre
62% HN0
3
per 100 litres water.
•
Excess Nitric acid can seriously damage Nitrile
rubber gaskets.
Several alternative acids to Nitric can be used,
Phosphoric acid can be used at up to 5% and 85°C.
Consult APV to find all the alternative CIP regimes
possible.
7.3.3 Measurement of solution concentration.
SODIUM HYDROXIDE (NaOH) solution is titrated with
0.1 n HYDROCHLORIC ACID (HCI) with methyl
orange or methyl red as indicator.
NITRIC ACID (HN0
3
) solution is titrated with 0.1 n
SODIUM HYDROXIDE (NaOH) with phenolphthalein
as indicator.
Caution
The heat exchanger must be thoroughly
drained and rinsed immediately following
CIP. Residue from CIP may cause
corrosion if left in the heat exchanger.
Kemper County MM218132 Approved