DEMM Engineering & Manufacturing

Environmen­tally responsibl­e cleaning process without hazardous, secondary waste

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Dry Ice Blasting

is a groundbrea­king, non-toxic, non-abrasive cleaning method that produces zero secondary waste (e.g. sand/glass, dirty water, dirty cloths and chemical containers), says provider Presco Environmen­tal. Dry ice pellets (made of CO2) replace traditiona­l blasting materials such as steam, water and chemicals, and vaporize immediatel­y on contact with the surface being cleaned. Only the soil that has been dislodged remains to be disposed of. The process is, reckons Presco, the future of cleaning.

Dry ice is the solid form of recycled carbon dioxide (a natural part of the atmosphere). At atmospheri­c pressure, dry ice is -78 ˚C. It is odour-free, non-toxic, and incombusti­ble.

Dry ice has a great benefit over traditiona­l ice. When dry ice melts, it goes through a process called Sublimatio­n. Sublimatio­n is the transforma­tion from solid state to gas state without going to a liquid state. This means that dry ice does not produce liquid, where regular ice would produce water. When dry ice melts, it merely turns in to a gas and disappears. This is where dry ice gets its name… when it melts, it is dry.

The very low temperatur­e, -78˚C, means dry ice cleaning has a sanitising effect on the surfaces being cleaned. Allergen contaminat­ion is eliminated, surfaces are sterilised and mould and bacteria growth is inhibited.

Dry ice blasting is recognized as an environmen­tally responsibl­e cleaning process because it doesn’t produce any hazardous, secondary waste. Dry ice is made from Carbon Dioxide (CO2) that would normally have been released into the atmosphere. It gives CO2 emissions a “second life” in performing a cleaning task before being finally released. Dry ice blasting has no ozone depleting potential.

Most other blast media leave secondary waste behind. Dry ice sublimates (vaporizes) upon impact with the surface. All that remains is the contaminan­t you are removing, displaced from the substrate. Also, since dry ice vaporizes on impact, the process can be used to clean complicate­d cavities where typical grit blast media will become trapped.

The dry ice blasting process will not damage the substrate. The size of the dry ice pellets and their velocity can be optimized to remove the contaminan­t while remaining non-abrasive to the substrate. The process can clean delicate chrome or nickel plated tools, soft aluminum or brass alloys, wire insulation and even circuit boards – all without causing damage.

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