Abstract: There is disclosed a method of and an apparatus for performing, using a sandblasting, a processing such as a chamfering of a workpiece which has a surface to be processed and a surface not to be processed located adjacent to each other. The workpiece (W) held by a holder (2) on a turntable (1) is transferred to a processing station (P.sub.1) by the rotation of the turntable (1). An injection nozzle (3) or (4) is directed toward the surface to be processed (f.sub.1) of the workpiece (W), while a jet nozzle (5) is directed toward the surface not to be processed (f.sub.2). The jet nozzle (5) is supplied with fluid such as air, and the nozzle (3) or (4) is supplied with air containing abrasive grains. The fluid discharged from the jet nozzle (5) prevents the abrasive grains from impinging against the surface not to be processed (f.sub.2).

Abstract: A method and apparatus for sandblasting a workpiece. The workpiece is placed at a machining position. Air is sucked around the workpiece at the machining position in a first direction to produce air streams. During sucking, abrasive grains are blown against a face of the workpiece in a second direction for sandblasting the work, the second direction crossing the first direction at an angle .theta. smaller than 90.degree.. Abrasive grains blown against peripheries of the workpiece are larger in velocity than abrasive grains blown against a central portion of the workpiece.

Abstract: An apparatus for producing well-fermented compost by achieving an aerobic fermentation of organic wastes, excretion, etc. The apparatus comprises a fermentation vessel of a rectangular configuration, a device for feeding slurry-like organic wastes within the base compost which has been piled in the vessel and for stirring the base compost and the slurry-like organic wastes, and a device for gathering an upper portion of the predetermined thickness of the fermented compost and for carrying the gathered compost out of the vessel. These devices are movably positioned on the top of the vessel.