Process for spraying the bits and/or the facing with pressurized liquid

Abstract

For reducing the risk of any overheating when cutting or crushing rock by means of a partial cut cutting machine and for facilitating crushing or, respectively, cutting of the material, a pressurized liquid, for example water, is intermittently sprayed within an area facing the area to be excavated. Said mentioned area facing the area to be excavated is realized in connection with a cutting head by providing within a range of center angle of the rotating movement of the cutting head a plurality of radial perforations (18) adjoining an axial bore (8) for the supply of pressurized fluid, noting that this range of central area corresponds to that area which faces the area to be excavated or, respectively, the mine face. Radial channels (22) of the cutting head coincide during rotation of the cutting head (1) with the radial perforations (18), said channels feeding the pressurized liquid to the exit openings provided on the periphery of the cutting head (1). The radial perforations (18) are arranged within a center angle of less than 180.degree., preferably 120.degree. to 150.degree., and with predetermined rotating speed of the cutting head (1) this provides the possibility to realize preferred ejection frequencies between 10 and 20 Hz.