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Example of an acceptable solution for dairy
applications and AISI 316 plates and NBR
gaskets:
• Oils and fats are removed with a water-
emulsifying oil solvent, e.g. BP-System
Cleaner.
• Organics and greasy coatings are removed
with Sodium hydroxide (NaOH) -max.
concentration 2.0% - max. temperature 85°C
(185°F). 2.0% concentration corresponds to
5.0 litre 30% NaOH per 100 litre water.
• Mineral scale deposits are removed with
Nitric acid (HN0
3
)-max. concentration 0.5% -
max. temperature 65°C (150°F). 0.5 %
concentration corresponds to 0.58 litre 62%
HN0
3
per 100 litres water.
• Ì! Excess Nitric acid can seriously damage
NBR and other types of rubber gaskets.
• Non-organic deposits can be removed by
special APV Clean.
• Several alternatives to Nitric acid can be
used, e.g.: Phosphoric acid up to 5% and
85°C.
9.3 Regular DuoSafety internal inspection
Regular internal DuoSafety plate pair
inspections must be made. APV recommends at
least an annual inspection for AISI316 heat
exchangers. The plate heat exchanger must be
opened and the DuoSafety plate pair separated.
Carefully check the inside surfaces for traces of
the product/ liquid processed in the heat
exchanger. If visual inspection of the surface is
difficult (e.g. because the product is transparent)
then it is recommended that indicator dye is
sprayed onto the inside surface of the plate pairs.
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