What is Cryogenics
Cryogenics is the science of low temperatures. At low temperatures, Carbon Dioxide can be used as an effective cleaning agent.
Carbon Dioxide or CO2 (See-Oh-Two) is an odourless, inert gas approximately 1½ times heavier than air and 0.03% is normally present in Earth's atmosphere.
It is also found in great quantities in volcanoes, earth cracks, in the metabolism of plants, animals, human beings and various other sources.
Commercially, CO2 can be recovered as a by-product from various chemical industries and is usually stored in a tank after recovery.
Carbon dioxide can exist in three forms:
- in gaseous form (for the beverage and food industries)
- in liquid form (in a storage tank under pressure)
- in solid form (called dry ice, for blasting, cooling etc.)
What is dry ice?
Dry ice is the solid form of CO2 and is produced from liquid carbon dioxide. Inside a dry ice pelletiser, the liquid carbon dioxide is expanded under
controlled conditions to form dry ice snow. This snow is then pressed through an extruder plate into round, hard pellets for dry ice blasting purposes
or into larger pellets/dry ice slices/blocks for cooling purposes. Dry ice has a temperature of approx. -79 °C.
How does dry ice clean?
The Dry Ice Blasting machine accelerates the dry ice pellets using compressed air to reach a speed of approximately 300 metres per second.
The pellets hit the object to be cleaned. The surface is shock-frozen in a fraction of a second. Due to the sudden thermo shock generated on the surface
to be cleaned, the coating/dirt contracts, becomes brittle and cracks. Due to the cracking of the surface, the pellets can reach under the dirt and remove it.
The additional kinetic energy removes the coating/dirt from the surface. Immediately after impact, the pellet sublimates and goes back to atmosphere as a
pure gas (CO2) without leaving any moisture behind. The only thing left is the coating/dirt removed from the surface and no blasting media has to be disposed of.
Since the hardness of the pellets is only approx. 2 Mohs, the cleaning is virtually non-abrasive, and the surface quality is maintained.
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Shock
As a result of the sudden and intense temperature shock on the surface, the coating or impurity contracts.
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Crack
As a result of the contraction the coating cracks and the material becomes brittle due to the cold.
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Clean
The dry ice pellets hit the surface with great speed and remove the detached coating and clean the surface material.
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Dry ice blasting basically removes all material which reacts strongly to differences in temperature. Paint, varnish, adhesive, oil, wax, residues in
bakeries, bitumen, synthetic residues and foams (e.g. PU) etc. are removed easily without damaging or altering the surface in any way. Even delicate parts
like switch boards and other electric components can be cleaned safely. As dry ice blasting is virtually non-abrasive, this technology is especially highly
recommended for gentle and effective cleaning of moulds of any type and material in all industries (e.g. ingot moulds, core boxes, injection moulds, high
pressure die casting moulds, moulds for PU-products, waffle irons etc.).
CO2 Blasting Benefits
| Decreased Downtime through Cleaning In-Place |
Many procedures require equipment to be cooled, disassembled and moved for cleaning. With dry ice blasting, equipment
can be cleaned in-situ and without cooling in most situations. Many time-consuming, labour-intensive steps can be eliminated.
Dry ice blasting reduces downtime from days to hours. |
| Fast and Thorough Cleaning |
Dry ice blast cleaning gives a superior clean when compared to scrubbing with abrasive pads or wire brushes. The CO2 blast
method cleans in crevices that cannot be reached by hand therefore achieving tremendous labour savings. |
| Elimination of Equipment Damage |
Cleaning methods such as sandblasting have an aggressive and abrasive effect on the surface, and can actually remove part
of the surface. Dry ice is non-abrasive and does not change a surface's structure. As mentioned, equipment can be cleaned in
place, eliminating potential damage when moving equipment. |
| Reduction or Elimination of Solvents |
Dry ice blasting uses no solvents. This can be a critical need for certain companies in order to comply with environmental
regulations or to improve worker safety. There are no issues pertaining to toxicity. |
| Reductions in Waste Disposal |
With other cleaning methods, the cleaning agent becomes a secondary contaminant and must be disposed of as toxic waste along
with the primary contaminant. However, with dry ice blast cleaning the CO2 pellet sublimates upon contact, meaning the only waste
created is the contaminant itself. |
| Increased Safety |
No secondary waste, non-toxic, safe for the environment, safe for employees, safe for equipment. |