Ice blasting (cleaning)
| Ice Blasting | |
|---|---|
| Industry | Industrial cleaning |
| Application | Surface cleaning and preparation |
| Fuel source | Water and Electricity |
Ice blasting (or wet-ice blasting, frozen-ice blasting, water-ice blasting) is a form of non-abrasive blasting where frozen water particles are combined with compressed air and propelled towards a surface for cleaning purposes. Blasting can be performed in different mediums. An alternate method of non-abrasive blasting is dry ice blasting using frozen CO2. Other forms of abrasive blasting use mediums such as sand, plastic beads, and baking soda.
History
A “Blasting Machine Utilizing Sublimable Particles” was patented in 1955. The blast media were pelletized dry ice and hence the process became known as dry ice blasting or CO2 blasting. Interest in Ice Blast renewed in the late 80’s as evidenced by numerous patents filed on the subject. The technology was based on adding cryogenic features in a natural progression from sand blasting. Without proper understanding of the static and dynamic property of ice particles, such implementation invariably led to ice particle agglomeration and subsequent ice blockages.
In 1995 Universal Ice Blast, Inc. was incorporated for the purpose of developing and marketing ice blasting equipment for which it held patents. The company designed, assembled and sold its equipment as well as providing ice blasting services and equipment rentals. The company created environmentally-friendly solutions to industrial cleaning needs. UIB held four patents two of which were issued in 1999, one was issued in 2001 and one was issued in 2003. These patents cover the method and equipment for manufacturing, transport, and continuous delivery of ice particles to a nozzle to do continuous ice blast cleaning work on various surfaces.
In 2012, Coulson Group of Companies acquired Universal Ice Blast and began the reorganization and improvements to the UIB technology, which took several years. In March 2015, the company was re-launched and re-branded as Coulson Ice Blast. The Coulson Ice Blast team is a group of specialized industry experts to cater to the various industries and educate customers on the advantages of the refined ice blast technology.
Method
Abrasive blasting is the process of impacting projectiles like sand or plastic beads to erode surface materials. If the hardness of the abrasive medium is higher than the substrate, the substrate surface may be damaged. Ice blasting is a non-abrasive cleaning process that uses frozen water particles as a medium that sublimates upon impact to prevent damage to the substrate. The most effective ice blast cleaning applications use consistent-sized particles to provide an even cleaning effect. The ice particles are combined with compressed air and directed towards a surface.
The cleaning method used in ice blasting falls under three steps:
- Bulk Removal: The stage where major contamination is first removed. Typically this is a physical removal by displacement (ie. Momentum transfer). This step is therefore best achieved with a material that transfers its momentum efficiently to contamination. Solids have better momentum transfer than liquids as they do not flow around strongly adherent contamination.
- Detail Cleaning: The stage where some form of mechanical agitation such as scrubbing or polishing is provided to remove minute quantities of the remaining contamination from the surface. By definition, scrubbing means two solids moving relative to each other under applied pressure. Water as a blast-cleaning agent therefore cannot offer this property.
- Final Rinse: The removed contamination is rinsed away. Water is a universal solvent for this action. Many alternatives to ice blasting requires an additional rinse on top of the blasting action.
This leads to the natural conclusion that ice particles which change state from solid to liquid at normal working temperatures are ideally suited for cleaning applications where stringent cleanliness is required and at the same time the use of cleaning chemicals are not desirable. The ice particles provide impact cleaning before the phase change, which then scrubs and flushes away contaminants, which can be easily collected and disposed. Ice particles will melt into water and some of the water will undergo forced evaporation arising from the blast air movement. In warm climates, complete evaporation can take place, leaving only damp blast debris. This aspect of ice blast is of particular interest to those concerned with waste generation and disposal, especially in the cleaning of hazardous chemicals. Waste minimization is also important for the cleaning of industrial spaces where floor drains are not common.
Equipment
Ice particles as a medium for blasting can be created from a solid mass of ice, or through creation of individual ice pellets. In a rotating ice drum, a sheet of ice would have enough internal stress to self-fracture and provide even particles for blasting. Individual ice particles can also be created through a super cooling a mist of water by adding liquid nitrogen for a cooling effect. The cost of ice blasting is relatively low compared to alternatives because the medium (frozen water) is cheaper than dry ice or other abrasive media. Ice blast technology was patented by Universal Ice Blast and purchased by Coulson Ice Blast, Inc. The patent covers a method and apparatus for substantially continuously producing a stream of ice particulates for use in performing ice blasting work on a work object.
Applications
Ice blasting can be used to effectively clean many different surfaces and has applications across multiple industries. It has an appeal because of its minimal water usage and the absence of chemical ingredients to provide an eco-friendly cleaning solution. In addition, ice blasting does not damage the surfaces being cleaned.
Lead paint/Abestos Removal
In paint-stripping, ice blasting is used to overcome the cohesive bond of the coating. Depending on the paint or makeup of the bond, some coatings cannot be cleaned. Ice blasting is especially useful in removing lead paint, as it poses the least danger. Ice blasting has the lowest level of airborne contaminants for blasting technology in removing lead paint. Ice particles produce a blast mist, which helps to suppress dust or airborne particulates to minimize unintended dispersion. This characteristic of ice blast is of particular interest in terms of worker health and safety in the abatement process of asbestos and lead-based paint.
Molds
Ice blasting technology allows for thorough and efficient cleaning for molds in a wide range of industries, including tire manufacturing, automotive production, and packaging plants. Since the method is non-abrasive, the cleanings will not damage molding surfaces. Ice blasting can be used on hot or cold molds, reducing the downtime in production facilities. Ice sublimates on impact, so entrapment of the blasting media is not a concern. Grit entrapment is the reason abrasive media such as sand cannot be used to clean online.
Deburring
In some applications, material removal is achieved without abrasion. This is particularly common in the removal of fine burrs arising from machined aluminum such as automatic transmission components, and small flashings from castings. In these situations, the metal is loosely attached to the parent metal and hence can be readily displaced by the momentum of the blast agent. No abrasive erosion takes place as the remaining metal does not exhibit a smooth or rounded edge.
Oil/Grease
The scrubbing pressure of ice particles can be up to 300 bar. In many applications in oil and grease removal, ice blasting can produce essentially oil-free surfaces. In some metal finishing operations, ice blast has been shown to be superior to conventional acid pickling.
Rust
Ice blast is not abrasive. It does not remove strongly adherent tough coatings like abrasive media would. However, ice blast can remove coatings with weakened adhesion resulting from coating defects or corrosion. As an ice particle impacts on a coating, it causes a compressive stress on the coating and target system. On impact, the ice particle melts. The coating and target system under compressive stress will react in the opposite direction, producing a tensile stress. When the tensile stress exceeds the coating adhesion force, coating lifting takes place. The lifted coating is in the force of chips and would be carried by the residual water.
Other Uses
Ice blasting has applications in many other industries and is a solution for companies that value effective use of water, a low environmental impact, and low cost. The technology has been used for aerospace, chemical removal, nuclear decontamination, and municipal cleaning.
Safety
As with all blasting technology, proper eyewear and ear protection is recommended, as blasting machines reach levels of 115 db. Depending on the contaminants being cleaned, the level of protection varies. Ice blasting is the safest method of blasting technology because of the lack of air pollutants consistent with other blasting technology. Generally, light rain gear is sufficient protection. If ice blasting is used to clean hazardous materials, heavier protective clothing is recommended.
See also
References
- Ing, Habil and Karpuschewski, Bernhard. "Cyrogenic wet-ice blasting - process conditions and possibilities" Institute of Manufacturing Technology and Quality Management (IFQ), Otto-von-Guericke-University of Magdeburg, Germany. 2013.[1]
- "What is Ice Blasting?". Cyrogenic Blasting - Precision Ice Blasting. 2009.[2]
- "Coulson Ice Blast- How It Works". Coulson Ice Blast. 2015.[3]