Carbon dioxide pellet blast and carrier gas system

Abstract

An improved blast cleaning system and an improved method of blast cleaning using solid carbon dioxide pellets is provided. A compressed air source--preferably an air compressor--is used to produce a compressed air or carrier gas stream which is cooled to the desired temperature by injection of a cryogen--preferably liquid nitrogen--before the solid carbon dioxide pellets are introduced into the carrier gas stream. Solid carbon dioxide pellets are then added to the cooled compressed air stream and then propelled towards the surface to be cleaned. Using a compressed air stream which is precooled to the desired operating temperature helps to minimize the sublimation of the carbon dioxide pellets. The use of the precooled compressed air stream also allows greater control of the hardness, size, density, impact forces, stripping rates, and stripping efficiencies of the carbon dioxide pellets. An improved method of transporting solid carbon dioxide pellets which can be used for nonblasting applications (e.g., charging shipping containers for frozen or chilled foods) is also provided.

Dependencies are inferred from the claim text.