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USAGE OF DRY ICE IN DRY ICE BLASTING

dry ice blasting

Dry ice blasting is a relatively new cleaning process using solid pellets (known as dry ice). It is primarily used for industrial use in a variety of applications. The pellets sublimate (convert directly from a solid blast pellet to a vapor) leaving no residue, hazardous waste or toxic fumes. Today, the dry ice method of cleaning is quickly becoming favored for environmental as well as production reasons. Because of tremendous environmental regulations, industry has needed to minimize wastes. Further, there is a growing consciousness that many are placing now on the global environmental impact of their production practices. However, these benefits are accentuated due to the tremendous performance gains through dry ice blasting -- little or no production downtime, quality of clean and minimized damaged to equipment.

Dry ice blasting is similar to conventional shot blasting except that the shot is replaced by pellets of dry ice which literally disappear as soon as the cleaning cycle is complete. The dry ice particles are propelled to supersonic speed, to impact and clean a surface. The particles are accelerated by compressed air, available from standard industrial compressors. When the pellets impact on a substrate with a tightly bonded layer of surface contamination, or unwanted coating, the dry ice creates a layer between the substrate and the surface layer. Once between the surface layer and the substrate, the pellets complete their sublimation creating a large volume of Co2 gas which rapidly expands. The process provides a dry and abrasion free clean, and because the pellet media sublimates immediately upon impact (turns from a solid to a gas), there is no secondary waste disposal necessary.

Why is Dry Ice Blast cleaning so effective?

Kinetic Energy: As with traditional methods, the velocity and mass of the media upon impact transfers the required energy to the surface being cleaned. Whilst this principle is, traditionally, responsible for the majority of work in blast cleaning, it only reflects one aspect of Dry Ice Blast Cleaning.

Thermal Differential: The surface temperature of Dry Ice upon impacting the substrate surface is -78.6oC. The temperature differential established promotes contraction and expansion, which aids the removal process.

Reverse Fracturing: The Dry Ice particles sublimate immediately upon impact and enter through the spaces behind the contaminant at more than 550 times their original volume, pushing it cleanly away from the surface being cleaned.

Dry Ice Blasting Compared to Traditional Methods

The following two charts give a helpful perspective of how dry ice blasting compares with the traditional cleaning methods -- sand, blasting, solvents, and others:.

Dry Ice Blast Cleaning Comparison Chart
Blasting Cleaning Technique
Waste for Disposal
Abrasive
Toxic
Electrically Conductive
Performance Comparison
Dry Ice
No
No
No
No
Excellent
Sand
Yes
Yes
No
No
OK
Glass Beads
Yes
Yes
No
No
OK
Walnut Shells
Yes
Yes
No
No
Limited
Steam
No
No
No
Yes
Poor
Solvents
Yes
No
Yes
Yes
Limited

*Each of these blast cleaning materials becomes contaminated upon contact if used to clean hazardous objects. When that happens, these materials are then classified as toxic waste requiring safe disposal.

The above chart compares the various methods of cleaning with the dry Ice blasting. Each type of cleaning finds usage in specific industries.

CLEANING METHOD COMPARISION
Issue
Traditional
Dry Ice Blasting
Equipment Downtime Cleaned in dedicated cleaning area;Disassembly/reassembly; Drying time required Equipment can be cleaned in place; Dry process - equipment restart immediately after cleaning
Hazardous waste Cleaner becomes and treated as a secondary contaminant No additional contaminant .Dry ice sublimates with contact with targeted surface
Labor Hours Intensive hand scrubbing; Lengthy cleanings; Follow-up cleaning-up can be lengthy Dramatically reduced - often completed in a quarter of time or better
Quality of Cleaning Poor to average Excellent
Potential Equipment Damage Grit abrasions; Grit contamination; Movement of equipment to and from cleaning area No equipment damage; Preventive maintenance very realistic as labor hours are significantly less
Safety Health threats from solvents; Water-based cleaning pose hazards around electrical equipment; Standard safety precautions; Dry process - safe around electrical equipment
Cost Cleaner becomes additional hazardous waste; expensive solvents; Minimal - cost of dry ice
APPLICATIONS:

Dry ice blast cleaning applications are available to a multitude of industries offering tremendous value. In addition to the general benefits mentioned, dry ice blasting has specific benefits to some of the following industries:

Airlines/Aerospace
Utilities
Automotive
Electrical
Foundries
Food Processing
General Maintenance
Mass Transit
Marine
Pharmaceuticals
Plastics
Printing/Plating
Pulp and paper
Rubber
Benefits Of DRY ICE BLASTING :

1 - Decreased Downtime through Cleaning In-Place
2 - Faster and More Thorough Cleaning
3 - Elimination of Equipment Damage
4 - Reduction or Elimination of Solvents
5 - Reductions in Waste Disposal
6 - Increased Safety