Ice blasting (cleaning)
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. Ice is one of several different medias commonly used for blast cleaning. Another common method of non-abrasive blasting is dry ice blasting, which uses the solid form of CO2 as a blast media. Forms of abrasive blasting use mediums such as sand, plastic beads, and baking soda.
| Ice Blasting | |
|---|---|
| Industry | Industrial cleaning |
| Application | Surface cleaning and preparation |
| Fuel source | Water and Electricity |
History
The first ice blasting patent was filed in 1952, as a “means and methods for cleaning and polishing automobiles ” (US patent 2699403) [1].
In 1959, Unilever filed a patent for using ice blasting to remove meat from bone[2].
The first company to attempt to commercialize ice blasting technology was Universal Ice Blast Inc., established in the early 1990s based on a grant from the Navy, who were interested in using the technology to clean inside ship engine rooms and other such enclosed spaces on marine vessels.
The machines created by Universal Ice Blast made ice continuously. The blast media was in flake ice form. When a supply of water and electricity where connected into the machine, a cold drum would rotate continuously through a bath of water. A thin sheet of ice would form on the drum, before hitting a blade, which would shatter the ice sheet into small flakes. These flakes would then be sucked up into a fast-moving air-stream and ejected out of a nozzle.[3]
The machines made by Universal Ice Blast used a "two-hose" system. Two-hose blasting systems use separate hoses for air and for the blast media (which is ice, in this case). The air hose is pressurized and ends in a converging-diverging nozzle. The air accelerates through the nozzle and reaches supersonic speeds. As the air becomes supersonic, its pressure drops drastically, creating a suction effect. This acts to suck the blast media up through a second hose, which is connected into the air-stream after the converging-diverging nozzle. The blast media is sucked up through the hose and merges with the supersonic air-stream, which acts to accelerate it. The mixture of ice and air is then ejected out the end of the nozzle.
Two-hose systems cannot accelerate the ice particles to very high speeds, since the ice is not in contact with the fast-moving air for very long and the suction system results in large losses in air velocity. In comparison, "one-hose" systems, where the blast media is combined with the air before the converging-diverging nozzle, tends to be much more powerful and reliable.
Universal Ice Blast was purchased in 2012 by the Coulson Group of Companies. In 2015, the company was rebranded as Coulson Ice Blast.[4] Coulson Ice Blast redesigned the technology, focusing around the more powerful and reliable one-hose system.
In 2017, Coulson Ice Blast came out with the IceStorm90 ice blasting machine. This was the first one-hose ice blasting machine. Ice cubes are loaded into its hopper. A crusher mechanism crushes the ice into smaller particles, more suitable for blasting. A rotary airlock then transfers the particles into the high pressure air-stream. The ice particles are transported, suspended in the compressed air-stream, towards a converging-diverging nozzle. As the air passes through the nozzle, it accelerates to supersonic speeds. The ice particles are pulled along by drag force and are accelerated to high speed as well.
The IceStorm90 is significantly more compact than previous ice blasting machines. The one-hose system also makes it very reliable and much more powerful. Ice cubes can be pre-made and brought to the worksite, or they can be produced continuously by ice cube machines.
Coulson Ice Blast is currently the only company to manufacture ice blasting equipment.
Method
Ice blasting is a method of industrial cleaning that uses a continuous supply of compressed air to convey and accelerate suspended ice particles to high speeds. The ice particles are ejected from a nozzle toward the surface to be cleaned. The ice particles impact the contaminant covering the surface, breaking it apart and knocking it off.
Ice blasting uses significantly less water than pressure washing (around 10% of the water). As a result, one of its main advantages is easier containment compared to other industrial cleaning technologies. A wet spray forms around the surface during blasting, helping to capture airborne particulates and drag them downwards. Blasted off contaminants collect in a slushy pile beneath the blast zone. This means that, compared to other cleaning technologies, a more minimal containment setup can be used. In addition, much less waste is produced, since the minimal leftover slush melts and evaporates, leaving behind only the blasted off contaminant for disposal.
Since ice blasting results in less airborne contaminants than other blasting medias and requires simpler containment setups, it is often used for removing hazardous substances, such as lead paint or asbestos, or for blasting in enclosed/indoor environments. It is also often used in areas where water is scarce, since it requires much less water than pressure washing.
Ice blasting cleans in three main stages:
- Bulk Removal: The stage where major contamination is first removed. Speeding particles of ice impact the surface, breaking apart the layer of contaminant and knocking it off. Since ice is a solid, it can deliver a much higher impulse force on impact than liquid water.
- Detail Cleaning: The stage where ice slides along the surfaces of the part. This provides a mechanical agitation that scrubs and polishes the surface, removing 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. Some of the ice melts on impact to form water, which washes over the surface. Water is considered the universal solvent and so dissolves and washes away remaining contaminants.
These cleaning mechanisms often leave metal surfaces much shinier than other cleaning methods.
Equipment
Coulson Ice Blast is the only manufacturer of ice blasting equipment. They sell the IceStorm90 and the IceStorm90+. The IceStorm90+ is capable of blasting with either ice or dry ice.
Ice cubes, made with any standard ice cube machine or purchased in bags, can be loaded into the IceStorm90. The machine has a crusher mechanism inside it, which crushes these ice cubes into smaller ice particles, suitable for blasting (the particles are around the size of a grain of rice). The ice particles drop into a rotary airlock, which transfers them into a high pressure air-stream. The ice particles become suspended in the air-stream and are conveyed through a blast hose towards a nozzle. The air accelerates through the nozzle and the suspended ice particles are accelerated along with it. The ice particles are then ejected out the end of the nozzle towards the surface to be cleaned.
The operator holds onto the nozzle and controls whether the machine is blasting or not by operating a trigger.
Like all blasting equipment, the IceStorm90 requires a continuous supply of compressed air from a compressor.
The IceStorm90's operating pressure range is from 80-200 PSI. It can blast at 0-5 pounds of ice per minute.
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
- Abrasive blasting
- Dry-ice blasting
- Sand-blasting
- Pressure washer
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.[5]
- "What is Ice Blasting?". Cyrogenic Blasting - Precision Ice Blasting. 2009.[6]
- "Coulson Ice Blast- How It Works". Coulson Ice Blast. 2015.[7]
Notes
- Means and methods for cleaning and polishing automobiles, 1952-05-24, retrieved 2018-09-24
- Method of removing meat from bone, 1960-01-21, retrieved 2018-09-24
- Method for ice blasting, 1996-06-07, retrieved 2018-09-24
- "Welcome". Coulson Ice Blast. Retrieved 2018-09-24.
- http://integrita.zcu.cz/download/skola2/magdeburg_prez.pdf
- http://www.cryogenicblasting.com/page2/page2.html
- "Archived copy" (PDF). Archived from the original (PDF) on 2016-03-04. Retrieved 2015-10-05.CS1 maint: archived copy as title (link)