Cleaning
of porous metal filter elements can be
accomplished in two ways: in situ (in place) cleaning or
removal of
elements from their housings for cleaning.
In situ cleaning
in liquid/solids systems can be accomplished
Do
not mechanically clean porous metal elements.
Wire
brushing, scraping, sand or glass bead blasting can
smear the pores and close off the
porous media.
Chemical cleaning of porous
elements:
Chemical cleaning follows a
logical sequence: First, determine
what contaminants are present in
the filter. Next,
determine the chemical agents that
will dissolve these
contaminants (without dissolving
or attacking the porous
metal). The chemical agents
compatible with 316L stainless
steel porous media include, but
are not limited to:
•
Water at any temperature
• 15% nitric acid at up to 150°F
• 20% caustic up to 212°F
• Alcohols
• Acetic acid
• Acetone
• Ammonia
• Organic solvents
• Methylene chloride
• Industrial cleaners such as Oakite 31 or Sonicor #103
(to remove grease)
• Solvents and detergents
Soak
the elements in the chemical agent as required,
flush with clean, filtered water
or other compatible fluid,
blow out with clean air or steam.
Two chemical agents
may be required, such as 15%
nitric acid to remove iron
oxide and 20% caustic to remove
aluminum particulate,
with a water flush between soaks.
Back
to porous filter cartridges.