DRY ICE BLASTING FREQUENTLY ASKED QUESTIONS

In this section you will find answers to your questions about
dry ice cleaning

What is dry ice blasting?

Dry ice blasting

is an innovative and environmentally friendly cleaning technology that uses solid carbon dioxide (CO2) particles, commonly known as dry ice

or dry ice, as a cleaning agent. These particles are propelled at high speed onto the surfaces to be cleaned thanks to a pneumatic spraying system. Upon impact, dry ice undergoes instant sublimation, going directly from a solid to a gaseous state, without passing through a liquid state. This creates a thermal shock to the contaminated surface, which allows particles or layers of dirt to be loosened without damaging the substrate.

This process is extremely effective in removing various types of contaminants, such as greases, oils, waxes, production residues, and even some coatings without requiring the use of chemical solvents, water, or abrasive methods. It is therefore particularly suitable for cleaning sensitive parts or in environments where the use of water is prohibited or undesirable.

The speed at which dry ice particles are propelled depends largely on the system used, as well as several adjustable parameters, such as pressure, air volume, and nozzle type. In general, dry ice blasting systems can be classified into two main categories based on their design and the speed of projection:

  • Twin-tube or venturi system: These systems allow for projection speeds of between 60 and 120 meters per second (m/s). They are often used for general cleaning applications where effective dirt removal is required without specific spray speed requirements. See
    twin-tube cryogenic machine
  • Single-tube system with supersonic nozzle : These systems are capable of propelling dry ice particles at speeds in excess of 290 m/s, providing increased cleaning capacity for more demanding tasks or for particularly difficult-to-clean surfaces. View
    Single-Tube Dry Ice Blasting Machine

In addition to its efficiency and environmental benefits, dry ice blasting is also valued for its ability to significantly reduce the downtime of industrial equipment, since it can often be carried out without dismantling machinery or equipment. This method also helps to extend the life of assets by avoiding premature wear and tear from more abrasive cleaning methods.

What is the origin of the technique?

The origin of dry ice blasting cleaning, also known as “dry ice blasting”, dates back to the 1950s. However, it was not developed and marketed as an industrial cleaning technique until the 1980s. This method was invented and explored as an alternative to traditional cleaning techniques, which used chemical solvents, pressurized water, or abrasive methods that could damage surfaces or be harmful to the environment.

The fundamental discovery behind dry ice blasting cleaning is the ability of dry ice to sublimate, i.e. to go directly from the solid state to the gaseous state without passing through a liquid state, in contact with the surfaces to be cleaned. This unique property allows contaminants to be effectively removedwithout leaving any residue, unlike traditional cleaning methods that may leave secondary waste or require additional cleaning.

The introduction of this technique has revolutionized many industries by offering a non-abrasive, waterless, and environmentally friendly cleaning solution. Dry ice blasting cleaning has proven to be particularly useful in sectors such as aerospace, automotive, food and beverage, plastics, foundry, and electronics, where the cleanliness of equipment and components is crucial and where the use of water or solvents can pose safety, quality, or environmental issues.

Since its introduction, dry ice blasting technology and equipment have evolved significantly, providing increased efficiency, better ergonomics for operators, and greater adaptability to a wide range of industrial cleaning applications.

How does it work?

Dry ice blasting works in three main steps, based on the use of dry ice in the form of pellets or particles:

  1. Spraying : Dry ice particles are placed inside a

    dry ice blasting machine

    and then accelerated to high speed using a jet of compressed air through a specially designed blasting nozzle. This acceleration allows the particles to hit the surface to be cleaned with a high kinetic energy (Ec=1/2 mV²)
  2. Thermal shock : The impact of dry ice particles on the surface creates a thermal shock that weakens the bond between the dirt and the surface. The temperature difference between the dry ice (about -78.5°C) and the surface causes the dirt layer to shrink rapidly, making it easier to peel off.
  3. Sublimation : At the moment of impact, dry ice goes directly from the solid state to the gaseous state (sublimation), considerably increasing its volume, in a ratio of 1 to 400 or 1 to 700 (depends on the ambient temperature). This change in state causes a rapid expansion that helps to “blow” dirt from the surface without abrasion or damage, while leaving the surface clean and dry, free of water or solvent residue.

This process allows for efficient cleaning without the use of chemicals, without generating secondary waste and without damaging surfaces, making it an environmentally friendly and safe cleaning method for many industrial applications.

What is the difference with sandblasting?

    Dry ice blasting and sandblasting are two methods of industrial cleaning, but they differ in their principles, media used, and impacts on the treated surfaces:

    Cleaning Media:

    • Dry ice cleaning: Uses solid dry ice particles that sublimate on contact with surfaces.
    • Sanding: Uses solid abrasive particles such as corundum, glass, roughness, etc.

    Mechanism of action:

    • Sanding: Works by abrasive mechanical action, where solid particles hit the surface and physically erode or remove dirt, paint, rust, etc.
    • Dry ice cleaning: Works by thermal shock and sublimation, where the cold contact of dry ice particles with the surface creates a thermal shock that weakens contaminants before sublimation expels them from the surface.

    Surface effects:

    • Dry ice cleaning: Non-abrasive, does not deteriorate the treated surface and leaves no secondary residues, as sublimated dry ice disperses into the atmosphere.
    • Sanding: Potentially abrasive, may alter surface texture or cause damage if improperly applied. Generates secondary waste (worn abrasive particles and removed materials) that must be collected and disposed of.

     

    Applications:

    • Dry ice cleaning: Ideal for precision cleaning, sensitive equipment, environments where water or residue is an issue.
    • Sanding: More suitable for removing thick coatings, rust, or for surface preparation prior to painting or coating, where abrasion is required.

     

    Environmental and safety considerations:

    • Dry ice cleaning: More environmentally friendly, reduces the risk of chemical contamination and minimizes operator exposure to hazardous chemicals.
    • Sanding: Can generate harmful dust and waste, requiring strict control measures for operator safety and environmental protection.

    In summary, the choice between dry ice blasting and blasting depends on the nature of the dirt to be removed, the type of surface to be cleaned, environmental considerations, and the specific cleaning goals. In addition, sandblasting generates a lot of dust and it is usually not possible to clean on site.

    What happens to dry ice when it impacts the surface?

    Upon impact with a surface, dry ice undergoes sublimation, changing from a solid to a gaseous state without becoming liquid. This process releases carbon dioxide (CO₂), a natural component of the air, which participates in essential ecological cycles such as photosynthesis. Although CO₂ is a greenhouse gas, its release in this context does not introduce chemical pollutants into the environment, integrating into natural cycles without directly contributing to global warming.

    What happens to the contaminant?

    During dry ice blasting, contaminants are removed from the surface in an efficient and controlled manner. Here is a precise and concise explanation of what happens to contaminants:

    • Dry contaminants : After detachment from the surface by dry ice blasting, these particles fall by gravity. They can be collected on a surface prepared for this purpose, such as a plastic sheet, making them easier to collect. Removal is then done simply using an industrial vacuum cleaner, or by direct collection for reprocessing or proper disposal.
    • Viscous contaminants : For more adherent substances, such as grease or oils, the cryogenic method also loosens them, but their collection requires specific planning. The process is achieved by guiding these contaminants from their initial location (point A) to a predefined collection point (point B), where they can then be treated or cleaned further, for example, using high-pressure cleaning or other appropriate methods to ensure complete removal.

    This strategic approach to contaminant pickup ensures that dry ice blasting is not limited to moving dirt from one point to another, but contributes to efficient and environmentally friendly waste management.

    Does dry ice cleaning damage the surface?

    The decohesion or detachment of the contaminant takes place at a certain energy threshold. When the decohesion threshold is below the damage threshold, it’s safe to clean. When it is higher, you could damage the surface.

    The hardness of dry ice is comparable to that of chalk.

    Since the majority of CO₂ cleaned parts are production equipment (cast iron, steel, stainless steel, aluminum) there is no damage. You can also clean more fragile substrates (surfaces) such as plastics, electronic boards, monuments, copper, fabrics, etc.

    A preliminary test will define the feasibility of the cryogenic cleaning project.

    Example of an application not recommended:

    Stripping a marine-grade varnish on softwood (pine, fir): thepressure required to loosen the varnish defibers the wood.

    Can hot equipment be cleaned on site?

    You can clean up to three or five times faster when the equipment is hot.

    The adhesion of the majority of contaminants is lower at higher temperatures.

    Dry ice sublimates at the moment of impact, unlike sandblasting which leaves abrasive media trapped in the gaps.

    Abrasive cleaning methods are generally prohibited in situ in industries.

    Does CO2 cool the surface?

    The level of cooling of the surface depends on three primary factors:

    a) the mass of the target surface

    (b) the duration of the application

    (c) dry ice consumption per hour

    A tire mold could typically drop by 175 to 162 °C during the application of dry ice cleaning.

    With a very thin mold, the temperature drop can be greater.

    The cooling of the tool is in the vast majority of cases minimal.

    Can the drop in temperature damage a hot mold?

    It’s unlikely, but it depends on the mass of the target object.

    Heavy molds, for example, will not be damaged at all because the drop in temperature is insignificant compared to the mass of the mold.

    With thin substrates with critical tolerances, you may need to test to determine if the drop in temperature will affect the surface structure.

    Will the process create condensation?

    Condensation can only occur if you cool the substrate (surface) below the dew point which varies according to the local climate.

    If you clean a hot mold, you are unlikely to cool the mold below the dew point. It is therefore rare to cause condensation.

    How is dry ice made?

    From liquid CO₂ under high pressure. When the pressure of liquid CO₂ drops at atmospheric pressure, 50% is transformed into gas and 50% into dry ice.

    The dry ice is then compressed into blocks, sticks or 3 mm pellets. This ice cream will then have to be placed in a suitable container. Find out how to store solid CO2 by clicking on the following link.

    How are dry ice pellets made?

    The pressurized liquid CO₂ is brought back to atmospheric pressure: dry ice is obtained.

    This snow is compressed and pushed through a die or matrix to form pellets.

    The machine capable of accomplishing this work is a pelletizer. There are 2 versions:

    hydraulic version,

    mechanical version

    The first version (hydraulic) offers a higher density of ice, therefore an increased stripping power.

    However, it is easy to work with mechanical glass.

    How much air do I need for dry ice blasting?

    Normally, a minimum of 4,000 l/min (4 m3/min) and a pressure of at least 6 bar is required, but this depends entirely on the application and the type of blaster (dry ice blasting machine).

    85% of applications are carried out at pressures of 6-7 bar 4,000-5,000 l/min, but many applications require much less air:

    • Example 1 : Electrical cabinet cleaning with ATX nano – Air volume required 800 to 1500 l/min (pressure see Instruction Manual)
    • Example 2 : Car seat cleaning with ATX nano – Air volume required 1200 to 3100 l/min (pressure see Instruction Manual)
    • Example 3 : Machine tool degreasing with ATX25-E – Air volume required 4000 l/min (pressure see Instruction Manual)
    What are the possible cleaning pressures?

    Dry ice blasting pressures range from 0.3 to 15 bar (ATX25-E).

    Some competing pickers, however, are set at maximum pressures of 7 or even 10 bar.

    Prefer strippers, which can work up to a minimum pressure of
    12 bar
    .

    Cryoblaster ATX Working Pressures:

    • ATX nano : 3 to 12 bar
    • ATX25-E : 0.3 to 15 bar
    • ATX25 : 3 to 15 bar
    Can the dry ice feed rate be changed?

    It all depends on the hardware manufacturer. Some machines are rated to a certain consumption.

    It is preferable to be able to increase or decrease the consumption of dry ice depending on the contaminant and pressure.

    The Cryoblaster ATX series includes a dry ice consumption regulator as standard:

    • ATX nano : 0 to 35 kg/h
    • ATX25-E : 0 to 75 kg/h
    • ATX25 : 0 to 65 kg/h
    Do you need an air dryer?

    The Cryoblaster ATX equipment is designed for a cleaning operation with dry and clean air (available in the majority of factories).

    Although the ATX series includes an internal micron filter as standard, an additional air dryer will be required in exceptional circumstances:

    absence of compressed air treatment at the customer’s premises,
    Rental of a compressor without a compressed air treatment system

    You should always bleed compressed air lines before connecting them to your ATX unit. This will remove any water and dirt that may be in it (see methodology Instructions for use of your ATX).

    Regarding the maintenance...

    Cryoblaster® cleaning units are designed to give you years of trouble-free operation with minimal maintenance:

    100% pneumatic dry ice cleaners : check the pneumatic oil level and filters from time to time.

    – Cryoblaster electro-pneumatic dry ice cleaners: no maintenance

    What are the best applications of dry ice blasting?

    The range of dry ice blasting applications is incredible.

    A small sample of our customers easily highlights this: Révillon (chocolate factory), Renault Trucks (trucks), ITW (electronic boards), Pyxidis (medical), SAB Group (aluminium foundry)…

    Dry ice blasting is excellent for cleaning in-line production tools because masking, or caulking, cooling, and disassembling are not required. We have achieved exceptional results by cleaning production equipment in foundries, plastics, food processing, printing, etc.

    Dry ice blasting

    is also

    common in the nuclear industry for decontamination.

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    Location: www.cryoblaster.com
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