Patent ID: 7484670

Claim:
Blasting method for cleaning surfaces, wherein liquid CO 2 is supplied via a feed line ( 32 ) into an expansion volume ( 34 ) having an enlarged cross section, is transformed into dry snow by expansion, and is fed under pressure, together with a carrier gas to a blasting nozzle ( 14 ), wherein the volume V of the expansion volume and the internal cross-sectional area A of the feed line ( 32 ) fulfill the relation V 1/3 /A 1/2 >3, and the mixture of carrier gas and dry snow is accelerated in the blasting nozzle ( 14 ) to at least approximately sonic speed, characterised in that the carrier gas is supplied under pressure through a blasting line ( 10 ) to the blasting nozzle ( 14 ), the liquid CO 2 is transformed into dry snow in the expansion volume ( 34 ) apart from the carrier gas in the blasting line ( 10 ) and the dry snow is introduced from the expansion volume ( 34 ) into the blasting line ( 10 ) upstream of the blasting nozzle ( 14 ).