Automatic Cryogenic Cleaning Dry Ice CO2

Automation Technologies Ltd
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Automatic Cryogenic (Dry Ice CO2) Cleaning Booth

Automatic cryogenic dry ice CO2 blast cleaning

Industrial and Factory Automation

Cleaning Booth

Embedded PC type with touch panel display

Control screen

cleaning engine block

Automated Cleaning Robotic System

Our cryogenic (dry ice) cleaning blast booth is something new - a practical and flexible application of the ultimate in precision cleaning technology.

The unit is based around the cryogenic cleaning process which to date has only been found in crude single function manually operated machinery. Our system takes this technology and presents it in a format whereby it can be easily adapted to meet a wide range of industrial requirements.

Cryogenic cleaning involves a jet of solid CO2 particles being fired at supersonic velocity and with great precision onto the area to be cleaned.

The various forces which are brought into play in the process are sufficient to totally remove all contaminate from the substrate leaving absolutely no effect on the cleaned surface area. As a safe, non-toxic gas, the CO2 is simply taken back into the atmosphere after the cleaning process.

The unit brings a wider practicality to cryogenic cleaning by combining the delivery jet with a six-axis robotic manipulator and co-ordinating them both from a fully integrated PC- based control centre. The unit is self-contained extremely easy to use and can cater for both special "one-off" cleaning requirements and programmed multiple repeated tasks.

Benefits

  • No residue
  • No costly waste disposal
  • Completely automated process
  • Dramatically reduced cleaning time
  • Very minimal surface abrasion
  • Simple operation
  • Compact unit
  • Completely self-contained

Applications

Applications for the unit are wide and are growing all of the time as more and more companies see the advantages over their existing methods of cleaning and indeed consider broader uses.

  • De-carbonising and removing contaminates from high performance automotive components. Currently being used by Cosworth Racing.
  • Cleaning of commercial aerospace components, currently in use with Rolls Royce
  • Removing chrome from plastics and metals for resurfacing
  • Removing and recovering precious metal coatings
  • Reclaiming contaminated electronics
  • Flash removal from plastic lenses

Machine Detail

The cryogenic cleaning booth is a completely self contained system. It integrates the ice delivery system, compressor, extraction and filtering, multi axis manipulator and powerful control system into an ergonomic sound attenuated booth. This integration makes the automated cleaning of parts a practical reality.

Dry ice, in the form of pellets is loaded into an integral hopper. The ice is precisely metered into a pre-heated high pressure air stream, which is then directed at the surface to be cleaned, via a specially designed blast head, driven by the servo-manipulator. Surface contaminants disrupted by the CO2 are driven from the surface into the interior of the booth, where they are extracted and trapped by particle filters. Exhaust air and CO2 are extracted from the booth chamber by the integrated extraction system.

The cleaning efficiency is such that in the case of combustion product removal, a small cylinder head, as pictured here, can be completely cleaned in less than 10 minutes.

Operation Detail

The built in 'fly by wire' manipulator is extremely easy to use and requires no programming experience. The blast head tool path is created by driving the blast head over the surfaces to be cleaned, using a plug-in joystick. The resulting path is recorded and can be stored and edited at will. Many different tool paths can be stored and used over again when cleaning identical parts. The tool paths can be named and retrieved using a Windows type HMI user interface, which is simple and intuitive.

The unit has a built in touch panel display from which all necessary functions can be easily accessed. The unit can be operated by a single operator.

Dry ice can be manually loaded in convenient pellet form into the integral hopper reservoir, which can hold 50 kg of ice, giving sufficient supply for up to 1 hour's continuous use. The system automatically delivers a precisely metered amount of ice into the compressed air stream and this is under total programme control and can be varied according to the surface to be cleaned. The resulting ice flow rate is automatically stored by the control system and retrieved whenever the particular programme is used in future.

The ice hopper continuously monitors the quantity of ice remaining and displays this on the HMI unit. The cleaning process is automatically interrupted to allow the operator to replenish the supply when it falls below a pre-determined level. The ice hopper is constructed from a highly insulating thermoplastic material, which prevents condensation occurring and the subsequent production of water ice, which can freeze and disrupt normal operations.

Principles of Dry Ice CO2 Blasting

Dry ice pellets cannot remain solid when exposed to atmospheric pressures and temperatures. When the dry ice pellets penetrate the contaminant and hit the substrates the friction slows them down and they begin to warm up. As the pellets warm up, they sublimate (turn from solid to gas) very rapidly. The expansion forces the contaminant which is no longer solidly bonded to be removed from the substrate.

As the dry ice sublimes, there is theoretically a liquid phase of CO2 formed during the impact process. As both the temperature and pressure rise rapidly, such a liquid phase would provide very rapid heat transfer from the coating (far faster than to a solid phase) and would allow its rapid percolation into cracks and pores, which would then suffer disruption during gasification.

Cost Reduction

The natural sublimation of dry ice particles eliminates the cost of collecting the cleaning media for disposal. In addition, contaminate and collection costs associated with water/grit blasting or solvent immersion are also eliminated.

Environmental Safety

Carbon dioxide is a non-toxic compound, which meets EPA, FDA and USDA industry guidelines. By replacing toxic chemical processes with CO2 blast systems, employee exposure and corporate liability stemming from the use of dangerous chemical cleaning agents can be materially reduced or eliminated completely.

Specifications

Typical size 2m x 3m x 1.7m (depending on variant)
Weight 2,600 kg
Power consumption 46 KVA
External sound pressure level less than 80 dba at 1m
Ice reservoir 50kg
Blast delivery pressure 10 Bar
Ice delivery Rotary air lock with flow control
Blast head Single hose - expansion chamber type
Waste extraction Negative pressure fan with integral
particle filter cartridge
Manipulator 6 axis cartesian servo driven
Controller Embedded PC type with touch panel display
Programming Simple joystick type (move and teach)

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