NOVEMBER/DECEMBER 2020 MAINTENANCE
AS COLD AS ICE
Dry ice can be used as an e ective – and waste-free – industrial cleaning method
BY DANIEL TOOK, HEAD OF PROFESSIONAL PRODUCTS, KÄRCHER UK
Manufacturing can only run smoothly
when every part of the process is
seamlessly linked, making wellmaintained
and clean machinery
imperative. On production lines,
cleaning not only ensures hygiene and
process safety, but also serves to maintain machines
and contribute to value retention. Every type of dirt
must be quickly and eff ectively removed without
interrupting the production process.
Dry-ice blasting as a mechanical
cleaning method
The cleaning of machinery and production
systems deserves special attention and dry-ice
blasting provides gentle and effi cient removal of
fats, oils, binders, adhesives and silicones from
various surfaces. This procedure is non-corrosive
and virtually non-abrasive, making it suitable for
cleaning, de-burring and removing paint from
delicate surfaces.
Dry-ice blasting is an excellent option when
conventional cleaning methods would be
unsuccessful or would require enormous extra
eff ort. It is also ideal when legislation prohibits
cleaning with water, chemicals, solvents or other
particle blasting methods.
The blasting medium is dry ice pellets: CO2
frozen to -79°C. When the pellets impinge on the
surface, the thermal eff ect causes brittleness and the
dirt cracks. This thermal eff ect is greatly assisted by
the speed of the pellets by an air compressor to over
150 m/s. The pellets penetrate the cracks created in
the dirt and revert to a gaseous state (CO2), escaping
into the air. The resulting increase in volume by a
factor of seven hundred causes dirt to be literally
blown from the surface.
Ice pellets are fed into a compressed air jet via
a dry ice blasting unit and hit the cleaning object
via a spray hose with gun and nozzle. Choosing the
appropriate device with the required performance
will depend on the cleaning task at hand. Things
to consider include ensuring a suffi cient amount
of air and enough air pressure, and the quality of
the dry ice pellets. Fresh dry ice should always be
used to ensure effi cient cleaning.
Within 24 hours, the density of
pellets reduces by 20%, aff ecting
the cleaning performance
signifi cantly and requiring much
more dry ice. Prompt delivery of
pellets shortly before cleaning
should be arranged or a pelletiser
is recommended in case of
constant or high demand.
The advantages of dry-ice
blasting are numerous. Dry
ice sublimes back into the
atmosphere as carbon dioxide,
so there is no waste-water and
no other spray agent residues.
Only the dirt falls to the ground,
which can be easily vacuumed or
swept away, incurring no waste
disposal costs for chemicals
or solvents. There is no risk of
damage to machinery and tools
and no disassembly is required,
resulting in little or no downtime
or production losses.
Cleaning industrial fl oors
Industrial fl oorings are usually
smooth, seamless, highly
compacted and heavy-duty
screeds upon which production
facilities stand or are bolted. They
are subject to traffi c and great
stress; as a result they must look
neat and be slip-proof.
When cleaning industrial
fl oors, the screed classifi cation
requires consideration, as
diff erent cleaning agents could
have a damaging eff ect. For
example, cement screeds are
sensitive to acidic and strong
alkalis, while calcium sulphate
screed cannot cope with lengthy
exposure to water, requiring a
one-step cleaning method. If
the fl oor has been treated with a
surface fi nish it may be hardened
and less susceptible to chemical
and mechanical stresses.
Maintenance cleaning
Red scrubbing brushes or pads
will remove light contamination
using a scrubbing and vacuum
machine set at low to medium
contact pressure and using the
one-step method. A cleaning
agent dosage of 0.5 to 3% –
depending on dirt entry – will
remove oil, grease, soot or
mineral contamination. Postwiping
is not required, and the
fl oor is immediately accessible.
Brake and skid marks are
usually found in turns and before
loading ramps and high-rise racks
and removal can be challenging.
A special, highly alkaline cleaner
agent (pH13) should be sprayed
undiluted onto the soiled areas
with a detergent sprayer and after
a contact time of fi ve minutes, a
scrubbing and vacuum machine
with green discs or roller pads
should clean and then rinse with
clean water (two-step method).
This method is not suitable
for polymer and wax coated
industrial fl oors as it would cause
them to dissolve.
Industrial cleaning is complex
and numerous considerations
will aff ect the results on fl oors,
machinery and equipment.
Working with an expert cleaning
partner is essential to ensure the
right procedures are in place to
safeguard the life of all facilities
and equipment.
Equipment must
be thoroughly
cleaned
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