Bead Blasting

Dry Ice Blasting - An Overview

The dry ice blasting (also known as CO2 blasting ) is a new cleaning process using relatively solid CO2 pellets (known as dry ice). It is mainly used for industrial applications in a variety of applications. The pellets sublimate (convert directly from a solid blast pellet to a vapor (CO2) leaving no residue. The process is superior to sandblasting, glass bead and other types of blast cleaning methods for many reasons (see table below).

Today, the dry ice method of cleaning is becoming a favorite for the environment as well as production reasons. Due to significant environmental regulations, industry needs to minimize waste. Also, there is a growing awareness that many are now placing on the overall environmental impact of their production practices. However, these benefits are accentuated due to performance gains through dry ice - little or no disruption to production, quality cleaning and minimize damage to equipment.

What is Dry Ice?

Dry ice pellets are made by taking liquid carbon dioxide (CO2) from a pressurized storage tank and spread to the ambient pressure to produce snow. The snow is then compressed through a die to make hard pellets.

Process

With the process of dry ice blasting, dry ice (CO2) particles are propelled at supersonic speed to impact and clean a surface. The particles are accelerated by compressed air, as with other blasting methods. Overall, there are three stages in dry ice. In addition, it can be viewed in chart form (see below).

Step # 1 - Transfer of Energy

Dry ice pellets are propelled out of the blasting gun at supersonic speed and impact of the surface. The transfer of energy hits out of the contaminant without abrasion. The strength of this impact is the primary means of cleaning.

Step # 2 - Micro-Thermal Shock

The cold temperature of dry ice hit the contaminant creates a micro-thermal shock (caused by the temperature of dry ice-109F) between surface contaminants and the substrate. Cracking and delamination of the contaminant to continue the process of elimination.

Step # 3 - Gas Pressure

The final phase has the dry ice pellet explode on impact, and the pellet warms converts it into a harmless gas CO2, which grows rapidly under the surface contaminants. This forces off the contamination behind. The contaminant is then transferred, usually falling to the ground. Since dry ice evaporates, the contaminant is left for disposal.

Operating Details

To use dry ice blasting equipment a few details need to be taken into consideration. Firstly, if the use of dry ice is extremely secure, the basic safety issues must be followed, including wearing hand, eye and ear protection. First, the process is noisy and hearing protection must be used. Secondly, the temperature of dry ice is -109 degrees Fahrenheit. Gloves should always be worn when working with her. Thirdly, in dusty, a mask is recommended to protect eyes and nose. Otherwise, the standard port eyes and ears that would be acceptable as with sandblasting or pressure washing. Fourthly, the weapon should never be made to another person or serious injury could occur.

In addition, blasting in a confined space is safe with adequate ventilation. Because CO2 is 40% heavier than air, placement of exhaust fans at or near ground Lev.