Dry Ice Blasting

Dry Ice Blasting Explained

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Dry ice blasting removes contaminants and coatings such as surface rust, dirt, and paint with a high-velocity stream of dry ice pellets. Dry ice cleaning, as this process is also known, is effectively media-less because dry ice, the solid form of carbon dioxide (CO2), sublimates. During dry ice sublimation, solid carbon dioxide turns directly into a gas with no intermediate liquid state. This change occurs at -78.5° C (-109.3° F) under normal atmospheric pressure of 1 atm. The equipment used for dry ice cleaning is portable or moveable and consists of a dry ice storage container, air compressor, hose, nozzle, and blast pot.

Abrasive ice blasting, a related process, mixes a high-velocity stream of dry ice pellets with an abrasive that provides added aggression for surface cleaning and contaminant removal. During abrasive ice blasting, the dry ice and abrasive feed together simultaneously and in a prescribed dosage. Some dust is produced, but it’s significantly less (up to 97%) than with sand blasting. With both dry ice cleaning and abrasive ice blasting, dry ice pellets can be cut into user-defined sizes of diamond-shaped particles to support application-specific requirements.

What are the advantages of dry ice blasting?

Dry ice blasting is a safe, clean process that is approved by the FDA, USDA, and EPA. It won’t harm surfaces, eliminates the need for harsh chemicals and extensive cleanups, and doesn’t require time-consuming scraping. Dry ice is a food grade material that is safe for commercial use and does not produce secondary waste streams, residues, or moisture. Because they sublimate, dry ice pellets can clean cracks and crevices without becoming lodged in challenging geometries.

The advantages of dry ice blasting are many. The media is non-abrasive, non-toxic, non-flammable and food-industry safe. The process is non-destructive and, compared to other methods, reduces equipment and facility downtime. For parts cleaning and surface finishing, dry ice blasting is suitable for holes and cavities with less than a 0.015” (.0381 mm) opening. Although dry ice sublimates too quickly for reliable measurements at smaller sizes, it is possible to clean cavities as small as 0.003” (0.0762mm).

How does dry ice blasting work?

Dry ice blasting spans three stages of shock and impact, all of which occur in milliseconds. Abrasive ice blasting adds a mixing step to the entire process, which is described below.

The first stage is thermal shock, a transient mechanical load caused by a rapid change in temperature. During dry ice blasting, thermal shock occurs because the surface contaminants or coatings freeze so rapidly that they become brittle and fracture. In more technical terms, the temperature-induced stresses and strains of such a rapid thermal change are greater than the ultimate strength of the material. This causes the surface coatings or contaminants to crack, which is necessary for their removal.

The second stage is impact, which occurs when the dry ice pellets strike the target surface at a high rate of speed.  During this collision, the energy and momentum of the dry ice particles is transferred to the surface material, which is already brittle and fractured because of the thermal shock from stage one. The result of this second-stage impact is the deformation and movement of the unwanted materials so that they begin to detach from the surface.

The third and final stage of dry ice blasting is expansion shock, which actually removes the surface contaminants or coatings. Expansion shock occurs because the heat transfer and rapid sublimation of the dry ice pellets produces an instant expansion of gas. When combined with the impact of the CO2 pellets colliding with the target surface, dry ice cleaning physically removes the surface contaminants or coatings. The sublimation of the dry ice also means that there is no media to cleanup.

Where to buy or rent dry ice blasting equipment

Nitrofreeze® of Worcester, Massachusetts (USA) provides Cold Jet® dry ice blasting equipment for sale or rent to companies across the Northeast and mid-Atlantic region. There’s a solution for every application, including:

  • smart dry ice blasters where you can digitally fine-tune parameters
  • pellet dry ice blasters for applications where more aggressive cleaning is required
  • microparticle dry ice blasters for more delicate cleaning
  • specialty blasters that use abrasive particles with dry ice for added aggression

With our Cold Jet New England Performance Evaluation Program (PEP), you can “try before you buy” and evaluate the success that dry ice technology has on your business over a set period of time through a trial rental. Upon purchase, the rental fee that you’ve paid can be applied toward the cost of your machine.

To learn more, contact Nitrofreeze® at the phone number and email listed below.

(508) 459-7447 x109 | info@nitrofreeze.com