News Article

Frozen Gas Pellet Blasting Licensed
Date: Feb 05, 2008
Source: ORNL ( click here to go to the source)

Featured firm in this article: Cryogenic Applications F Inc of Clinton, TN

An ORNL scientist who developed a technology for refueling experimental fusion energy devices and then adapted it for cleaning surfaces has received the right to manufacture and sell it for profit.

Energy Systems has signed a licensing agreement with Cryogenic Applications F, Inc., of Clinton, Tennessee, whose president is ORNL's Christopher A. Foster. The Clinton company has been granted the right to further develop and market an environmentally safe ORNL technology for surface cleaning. Specifically, it will be used to remove paint and radioactive contamination from surfaces by blasting them with pellets of frozen gases. The cleaning technology may replace the practice of washing parts with chlorine-containing solvents, which pollute groundwater and destroy Earth's protective ozone layer.

ORNL scientists Foster and Paul Fisher developed the cryoblasting process in conjunction with the Y-12 Plant. They are conducting a project for the U.S. Air Force at the Warner Robins Air Logistics Center (at Robins Air Force Base in Georgia) to develop a robot-compatible cryoblaster for stripping paint from military aircraft. Paint is removed so metal parts can be inspected for cracks and corrosion to determine if they can be placed back into service. As staff scientists with ORNL's Fusion Energy Division, Foster and Fisher hope to demonstrate to the Air Force that their cryoblasting process for stripping paint from aircraft is potentially faster, more efficient, and cleaner than other techniques.

A nonexclusive patent license agreement has also been made with Alpheus Cleaning Technologies Corporation of Rancho Cucamonga, California, for commercial use of the cryoblasting process technologies.

The licensed technologies include a method of freezing carbon dioxide and argon gases into pellets and a pellet-blasting centrifugal accelerator with an improved rotor and housing. Foster originally developed a centrifugal accelerator to fire pellets of frozen hydrogen gases (deuterium and tritium) into hydrogen plasmas to refuel fusion devices. One such centrifugal injector, which uses a high-speed wheel to accelerate the frozen pellets before injecting them into the plasma center, is used to refuel the Tore Supra tokamak in France.

"The advantage of the cryoblasting technique over conventional techniques for cleaning surfaces is that it does not leave a waste stream requiring additional cleanup," Foster says. "In cryoblasting, the frozen pellets evaporate into harmless gases, and the contaminants freed from the surface can be sucked from the air by vacuum systems with high-efficiency particulate absorbent filters."

The usual procedure for removing aircraft paint has been to bathe the planes in methylene chloride. Because use of this solvent is being discouraged by the Environmental Protection Agency, ORNL-developed centrifugal technology for blasting carbon dioxide, or dry ice, pellets may be useful to the Air Force and similar customers.

"A paint-stripping technology that uses compressed air to propel dry ice pellets is on the market," Foster says. "But our technology strips paint at a higher rate."

Cryoblasting also may replace sandblasting because it doesn't leave a sand-contaminated waste stream. At the Y-12 Plant, cryoblasting using argon pellets is being developed as a replacement for iron-bead blasting for removing oxides from metal surfaces. Because it is inert, argon will not react with reactive metals. Unlike the iron beads, the argon pellets evaporate into the air and do not add to the solid waste stream.

Larry Dickens of Energy Systems' Office of Technology Transfer negotiated the nonexclusive patent license agreement with Cryogenic Applications F.