| 摘要 |
Blast-processing apparatus (Figures 3 and 6) comprises turbine blower means (21) to provide blown air (241) as a vehicle for a blast-processing medium (201), conduit means (14), means (7, 8), to enable the blown air (241) to suck said medium (201) through the conduit means (14) from a reservoir (19, 27), and means (20, 145) to prevent the medium (201) from clogging an outlet (147) from the reservoir (19, 27) and/or from clogging the conduit means (14). Said prevention means (20, 145) comprise baffle means (20, 145), and are adapted to ensure that the ratio of the volume of the medium (201) in the conduit means (14) to the volume of the conduit means (14) is kept below substantially 20 % during the processing. Possibly, said conduit means (14) comprise a wander tube (144) with said prevention means (145) being located at its free end, which end is able to be placed into a free-standing reservoir (19) of said medium (201). Alternatively, the blast-processing apparatus comprises said reservoir (19), with said prevention means (20) being located within said reservoir (19). Said enabling means (7, 8) comprise Venturi means (7, 8) with an operative aperture (243) having a cross-sectional area (243) in the region of that size which will produce maximum suction. The blower means (21) comprise a plurality of turbine blowers (21) arranged to act side by side, and there is a reduced turbulence path (242) for air (241) blown from the blower means (21) as said vehicle. The apparatus comprises a hand tool (Figures 1 and 2) with an exit mouth (3) through which to apply said medium (201) to a workpiece (261), a brush (99) surrounding the exit mouth (3) to maintain substantially sealing contact with the workpiece (261) in order to contain the medium (201), and a return conduit (15) for the used medium (201) with an inlet mouth (4) adjacent to, and surrounding, said exit mouth (3). The hand tool (Figure 1) comprises a member (7) rotatable to vary the amount of the medium (201) able to be entrained by the blown air (241). The apparatus comprises variable air inlet means (262, 263) to the turbine blower means (21). There may be used a blast-processing medium (201) comprising pellets (270, 271) of non-woven fabric, preferably with some (271) of the particles being different from others, e.g. being impregnated with a substance which transfers to the workpiece (261) upon impact. |
