| 摘要 |
In contrast with the known method of cleansing surfaces by the projection of sand particles in an air stream against the surface, the present invention proposes to project particles of ice or other frozen liquid at the surface with the result that the spent particles will thereafter melt at the ambient temperature and be readily removed from the site and separated, if necessary, from contaminants dislodged from the surface. Apparatus according to the invention comprises means for the introduction of ice particles continuously into a stream of pressurised air, preferably mixed with water. The means may comprise a plurality of containers, each successively passing between a position where they receive ice particles from a supply and a position where they release the particles to the stream. |
