The Dry Ice Blasting Process
What is dry ice?
Dry ice is carbon dioxide in solid form. It is made from CO2 gas, which is derived from natural sources, and as a byproduct of many industrial processes. Dry ice is very cold (minus 109.3 degrees Fahrenheit), but is proven to be a safe cleaning agent/blast media, when handled properly. Most dry ice blast machines use a form of dry ice called pellets. Our PHX-150 and PHX-200 machines use this common pellet form of dry ice, but also are capable of creating smaller, gentler ice particles, for blasting electrical windings and other sensitive substrates. Call us to discuss your specific needs.
How does the process work?
Dry ice blasting is much like pressure washing, or sandblasting, since there is a media being moved at high speed, under pressure, to clean a specific target surface. But this is where the similarities end. Dry ice is dry, so there is no danger of short circuiting electrical equipment or rusting bearings. It is non-conductive, so it can even be used on energized circuits1. It is non-abrasive2, so it will not damage most surfaces. Think of dry ice blasting as being like a spatula, lifting the contaminant from the surface, rather than an ice pick, chiseling away from the top down. And the best part is that it disappears, leaving absolutely no residues or secondary waste stream. Dry ice is a “food grade” product, meaning it can be used in food manufacturing, food preparation facilities and is FDA approved. There is no grit entrapment to cause damage to your expensive machinery or hazards associated with dust migration.
Because there is no secondary waste stream, dry ice blasting is ideal for in-plant maintenance and production cleaning. Equipment that once had to be disassembled, transported to a cleaning booth, either sand blasted or tediously hand cleaned, then transported back and reassembled and calibrated, can now be cleaned in place, with little or no disassembly, greatly reducing costly downtime. The only waste to clean up afterward is the grime, ink, mold release, oil, loose paint or whatever contaminant was removed. Likewise, in the restoration applications (mold, fire, etc.) total job time is greatly reduced due to the fact there is very little post-blast cleanup required.
There are several mechanical processes happening when dry ice particles strike a surface. Depending on the type of blasting system being used, air pressure and nozzle selected, the ice particles travel at speeds between 600 and 800 feet per second. Upon impact they sublimate into CO2 gas. There is an expansion factor of 8 X as this happens, so assuming the particles are able to initially penetrate the contaminant, this expansion occurs at the underlying substrate, thus lifting the contaminant off. There is also a thermal shock effect, as the particles are at sub zero temperatures (-109.3 F). Many applications are able to clean faster because of this effect, most notably hot tooling, such as tire molds.
1. Special air treatment equipment and nozzles required. Live electrical cleaning
should be done only by qualified technicians
2. Relative to other blast media