Method of collecting dust during rock drilling and a dust collecting suction system for a rock drilling apparatus

Claim 1

Dust collecting suction system for a rock drilling apparatus comprising a hood (11) arranged to collect the dust loaded flushing air that flows out of the borehole, a coarse dust separator (13) having at least one inlet (22,23) coupled to the suction hood, a filter unit (14) coupled to the coarse dust separator (13), and a suction unit (15) coupled to the filter unit (14) to suck the flushing air through the coarse dust separator and through the filter unit, the coarse dust separator (13) comprising: a separator chamber coupled to said at least one inlet (22,23) for receiving said flushing air, said separator chamber including passage means defining a sharp bend in which said flushing air is diverted, a collector (32,33) in communication with the separator chamber adjacent said sharp bend for collecting coarse dust from the flushing air flowing through the separator chamber, the coarse dust, because of its inertia, not going with the air through said sharp bend, the flushing air from which the coarse dust has been separated being fed to the filter unit (14) for filtrating, a closed container (26) for the collected coarse dust, cleaning means (37, 38, 39) for cleaning the collected coarse dust from remaining fine dust by an air current, said cleaning means (37, 38, 39) including a substantially vertical elongated tube (37) coupled between the collector (32,33) and the closed container (26), the length of the elongated vertical tube (37) being several times the diameter thereof, and means (38, 39) coupled to the elongated vertical tube (37) for providing a current of air up through the tube (37) to clean the coarse dust that falls through the tube (37), the upward current of air from the tube (37) being fed to the filter unit (14) for filtration, and means (27) coupled to the closed container (26) to permit the coarse dust collected in the closed container (26) to be dumped on the ground.