Abstract: Method and apparatus for controlling the exit velocity of solid/gas carbon dioxide spray cleaning systems. By increasing the pressure of liquid carbon dioxide in the supply line, typically in the range of 800-875 psi, to greater than 875 psi, preferably 2,000-5,000 psi and above, the velocity of the spray stream exiting the nozzle is increased enabling removal of contamination (oils, fingerprints, particles, graffiti, etc.) not removable with a spray stream using conventional carbon dioxide pressures. The apparatus includes the incorporation of a high-pressure pump in the liquid carbon dioxide supply line in combination with a nozzle having a first or inlet orifice smaller in diameter than the supply line and a second or exit orifice larger in diameter than the inlet orifice.

Abstract: An improved apparatus and method for removing trace contaminants from the surface of a chosen substrate, such as delicate surfaces or precision parts, wherein the improvement consists of heating a portion of a chosen substrate surface immediately before, during and/or after application of a stream of cleaning snow to the same portion of the substrate surface.