What is Ortech dry ice pellet blast cleaning?
It is a process in which dry ice (solid CO2) pellets are propelled
at supersonic speed, to impact the surface that is to be cleaned
or prepared. The pellets are accelerated by a stream of compressed
air in a controlled manner through a blasting machine, just as
with other traditional blasting systems (sand, bead, soda, solvent
and other blasting). The unique feature of dry ice is its ability
to vaporize upon impact leaving no secondary waste. Today, most
applications are able to be cleaned by the use of standard shop
air, in the 30-¬90 psi range.
2. How to store the dry ice pellets?
Dry ice pellets should be stored in an ruggedly built insulated
container. The thicker the insulation, the slower will be the
sublimation rate. Depending upon the atmospheric condition, the
quality of the container and the insulation thickness, usual dry
ice sublimation is approximately 2% to 8% per day.
3. What is dry ice and how dry ice pellets are prepared?
Solid CO2 is commonly referred to as Dry Ice. It is produced by
allowing liquid CO2 to expand to atmospheric pressure which forms
dry ice snow. This snow is then compressed and extruded through
dies to form pellets and nuggets. Pellets are cylindrical in shape
with a diameter of 3.0 mm and length varying from 8.0 to 16.0
mm. At atmospheric pressure, the temperature of dry ice is -78.5�C.
4. How does the Ortech dry ice blast cleaning process
Dry ice blast cleaning 3-step cleaning process: 1. Pellet Kinetic
Energy: This effect triggers fracture in the layer of the contaminant.
2. Thermal Shock Effect: The rapid temperature difference between
the pellets and the layers of the contaminant produces localized
high shear stresses between the successive layers of the contaminant
which results in speedy micro crack propagation leading to final
bond failure at the surface of the substrate. 3. Sublimation (Micro-Explosion):
The sublimation acts as micro-explosion that removes completely
the layer of contaminant from the substrate. Important to note
here that while removing a brittle contaminant the process literally
pill off the contaminant from the surface and for removing a malleable
or viscous coating the process flushes the contaminant from the
5. How does Ortech dry ice blast cleaning differs from
Sandblasting is a harsh cleaning technique since it scrapes /scratches
/ cuts / chisel the contaminant from the surface. Whereas Ortech
dry ice blast cleaning is a aggressive but gentle cleaning technique
that leaves no abrasive effect on the surface since it lifts the
contaminant from the surface.
6. Why one should use dry ice pellet instead of a traditional
blast media for cleaning?
The hardness of the dry ice pellets is only 2 Mohs, thus the cleaning
is completely non-abrasive however traditional blast media, like
sand, glass beads, plastic beads, walnut shell, etc are bound
to leave an abrasive effect on the surface irrespective of their
type, size, nature. Further dry ice pellet after impact sublimates
and goes back to atmosphere without leaving any waste of its own,
the only waste created is the contaminant itself, whereas all
traditional blast media leaves secondary waste behind. Also during
cleaning the intricate portion or interior parts the entrapment
of the grit media in the voids is a major problem. However since
dry ice sublimates on impact, the entrapment of the dry ice pellet
is not an issue.
7. What is the size of dry ice pellets desired for dry
ice blast cleaning applications?
By and large dry ice pellets with a diameter of 3 mm are used
for majority of the cleaning applications. However for some specific
applications, e.g. for very delicate surfaces, dry ice pellets
with a diameter of 1.5 to 1.8 mm can also be used. If the same
is not available then, another option is to use a pellet cutter
which cuts the standard dry ice pellets into crystal form and
reduces their impact on the surface.
8. Does the Ortech dry ice blast cleaning process useful
for complicated cavities?
Yes, since dry ice vaporizes upon impact, the process can be definitely
used for cleaning complicated cavities where conventional grit
blast media may get trapped.
9. What happens to the dry ice once it strikes the surface?
It does the work of removal of the contaminant from the surface.
Thereafter instantly sublimates and returns to the atmosphere
as carbon dioxide (CO2) gas without leaving any secondary waste.
10. What happens to the contaminant?
If the contaminant is dry and hard then it will break into small
parts/chips that can be swept away or vacuumed. However if it
is a wet substance like grease or oil deposit then we have to
take a systematic approach for cleaning like start at one end
and guide the contaminant to the other end from where it can be
11. Does the dry ice pellets or contaminates ricochet?
As dry ice pellets, upon impact sublimates and goes back to atmosphere
as CO2 gas practically they do not ricochet. As for the contaminant,
they are usually washed away by the stream of compressed air and
thus do not come directly back into the blast gun vicinity. However
safety glasses for eye protection is recommended at all times
during the cleaning operation.
12. Does the dry ice pellets cool the substrate?
Generally no. This is because the Ortech dry ice blast cleaning
process is very rapid and the dwell period is too short to cause
any significant change in temperature of the substrate. However
if the contaminant is too hard to remove in that case we will
have to increase the dry ice usage rate and in that case the mass
per targeted area will be more which will result in a marginal
drop in temperature only.
13. Does the process or the dry ice pellets damage the
substrate/surface that is to be prepared or clean?
Absolutely no. Because most of our application involves production/process
equipments, tooling and components that are made of cast iron,
stainless steel, mild steel, aluminium, and the various alloy
metals. Also the damage can never occur since the contaminant
that is to be removed from these surfaces has very less bonding
threshold than the damage threshold. However, when removing contaminant
from softer substrates like soft wood and some softer plastics
and fabrics, there level of deposition, nature, etc. must be examined
on a case-by-case basis and then and then only decision of cleaning
must be taken.
14. Can the Ortech dry ice blast cleaning process be used
to clean hot mold / surface online?
Yes certainly. The process cleans best when the surface is hot.
Most contaminants have much weaker adhesive strength when they
are in hot condition. Further the temperature change of the surface
being cleaned is negligible compared with the mass of mold and
the corresponding tensile stress will be well below the point
of what most mold/surface will encounter during normal heat treatment.
However with very thin molds where tolerances are critical, some
testing may be required to determine if the drop in temperature
would alter the structure of the mold.
15. Will the process create condensation?
The cleaning agent i.e. dry ice pellets does not produce any moisture
or does not exists in liquid state at any point of time during
the cleaning process. However the condensation of the moisture
from the air surrounding the surface to be cleaned depends upon
the dry ice usage rate, the dwell time and the local climatic
conditions. Also the condensation occurs when the temperature
of the substrate fall below the dew point temperature. This condition
happens very rarely. When cleaning hot surfaces it is rare to
have condensation because we seldom cool them below the dew point
temperature. Even if condensation forms it can be dealt quite
easily using appropriate methods.
16. What equipments shall I need for the cleaning applications?
The Ortech dry ice blast cleaning system will come completely
with the dry ice blast and air hose, blast gun and nozzles best
suited for the cleaning applications and user friendly manual
to reference and train the staff. The other things needed for
the operation of the Ortech dry ice blast cleaning system is the
plant air, an electric power connection and the Ortech dry ice
17. How much air will be needed for effective cleaning?
The distinctive Ortech dry ice blast cleaning systems operates
at a pressure range between 4 to 6 bars with a volume flow rate
of 140 to 170 cfm for most of the applications. However your needs
will depend on the applications. OES has wide variety of nozzles
suitable for wide rage of flow rates and pressures.
18. Does one need an air dryer?
For dry ice blast cleaning applications the carrier fluid used
is compressed air. This has to be dry to ensure free flow of the
pellets till they make an impact on the contaminant. Ortech dry
ice blast cleaning systems operates with maximum efficiency when
the air is dry and majority of the plants are able to provide
clean and dry air. However where there is any doubt about the
quality of air then in that case it is always advisable to use
chillers or dryers. Moreover one should always blow down in plant
air lines before hooking them up to the dry ice blast cleaning
unit. This will eliminate water and sediment that may be present
and prevent these impurities from entering the equipment.
19. How much dry ice pellets are needed to clean effectively?
The amount of dry ice pellets needed to clean effectively can
vary significantly depending on the blast cleaning equipments
and the applications. The typical Ortech dry ice blast cleaning
system consumes approximately 26 to 52 kg of dry ice pellets per
20. Can one vary the dry ice pellet consumption rate?
Yes, one can easily vary and control the effective dry ice pellet
consumption rate by simply rotating the feed control knob located
on the control panel of the Ortech dry ice blast cleaning systems.
21. How portable are the Ortech dry ice blast cleaning
Ortech dry ice blast cleaning machines being very compact and
versatile one person can easily move any of the machines around
the plant at ease without the aid any special equipment.
22. Is it all right to use Ortech dry ice blast cleaning
process in an enclosed area?
Yes, but with proper ventilation. Because CO2 is 40% heavier than
air, we must have exhaust vents at or near ground level when blasting
in an enclosed area.
23. Is it okay to use Ortech dry ice blast cleaning outside?
Yes, the dry ice blast cleaning is safe to use in an open area
because there the existing ventilation is sufficient to prevent
undue CO2 buildup.
24. How much regular maintenance is required to keep the
system in perfect condition?
Very modest. Ortech dry ice blast cleaning systems are designed,
developed and manufactured in a way to provide a trouble-free
use and service with least amount of maintenance. The systems
are supplied with an operator manual which has in it the maintenance
schedule for each unit. With routine maintenance, one can expect
continuous service for many years.
25. What are the primary safety issues related with the
use of dry ice blast cleaning systems?
Ortech dry ice blast cleaning systems are designed in such a way
that the operator does not have the access to any moving parts
without switching off the unit. This invariably protects them
from the moving parts. Further the temperature of the dry ice
is very low (- 78.50C) hence the operator must wear gloves when
coming in contact with it. Likewise eye and ear protection should
be worn at cleaning times to prevent from any untoward accidents.
In addition to this the blasting gun should be pointed only on
the work piece than at anyone to ensure safe cleaning.
26. Does the system or the cleaning process creates noise?
Yes. Noise is a function of air volume and air velocity. Within
the nozzle, the stationary air is sheared by the high velocity
air causing turbulence which creates noise. With proper hearing
protection the operator can safely operate the system all day.
27. Does the process generate static electricity?
Yes. Any dry air process will generate static electricity and
Ortech dry ice blast cleaning is no exception. If both the blasting
system and the work piece that is to be cleaned is properly grounded,
then there won�t be any static discharge problems.
28. Does the dry ice blast cleaning techniques replace
the conventional cleaning methods like sandblasting / bead blasting
/ water blasting, etc.?
However consider that there is toll box containing different types
of pliers viz. gripping plier, special purpose plier, adjustable
pliers, cutting pliers, crimping pliers, rotational pliers, etc.
Could each do the job of the other? Obviously no, thus the ideal
toolbox would include each, because each has specific capabilities
that it does better than any of the others. Like wise although
Ortech dry ice blast cleaning has enormous advantages compared
with the traditional cleaning methods we recommend this technique
to those industries and organizations that are concerned predominantly
with downtime, entrapment, waste disposal volume, quality of cleaning,
abrasive effect, equipment life, toxicity, hazardousness, corrosively,
conductivity, etc. and moreover employee�s health, safety and
the environmental impact of the business.
29. What sort of contaminant can be removed effectively
by Ortech dry ice blast cleaning?
Ortech dry ice blast cleaning remove contaminants such as oil,
grease, adhesives, ink, dirt, dust, rust, carbon, soot, pulp,
paint, cadmium/cardium deposits, tar, food particles, water lines,
mold, cellulose, insulation, etc.
30. What cannot be removed?
Thick coatings of very hard material that have a strong bond with
the underground, examples are baked-on enamel on cast iron, primers
in car parts, silicate deposited on the blades of the steam turbine
rotor and diaphragms blades etc. Likewise it is difficult to remove
strong bonding contaminant from the base material that is too
soft, examples soft wood, plastic, etc.
31. What are the industries where dry ice blast cleaning
technique finds its applications?
The dry ice blast cleaning applications are as wide and diverse
as industries itself. The subsequently mentioned industries are
the ones where it predominantly finds its applications; airlines,
automotive, casting, chemical, dairies, electrical, electronics,
food, beverage, foundries, locomotive both diesel and electric,
moulding, packaging, paper, printing, pharmaceutical, power generation,
rubber, wood, etc.
32. How the Ortech dry ice blast cleaning system stands
apart in terms of reliability than other systems in the market?
The Ortech dry ice blast cleaning system stands apart in terms
of reliability than other systems in the market mainly because
of the following distinct features. It is a dependable single
hose system ensuring most aggressive, efficient and gentle cleaning.
It has a very operator friendly and precise control panel having
a safety instruction sheet with symbols and textual explanation
that are self explanatory. It is compact, versatile, light, durable,
reliable requiring very minimum maintenance because of specially
and masterly designed components. It is provided with a blasting
gun and a set of nozzles for substantiating the most perfect cleaning.
The gun provided with our system is so scrupulously designed that
by operating the controls on it the operator can control the systems
electric and pneumatic operation. Convince yourself by requesting
a demonstration. We will be happy to organize it for you.