LIQUID/LIQUID, LIQUID/GAS OR GAS/GAS SEPARATION Method General operations by centrifugal force, using centrifuges or free-vortex apparatus using magnetic or electrostatic effect Apparatus General operations by centrifugal force, using centrifuges or free-vortex apparatus , using magnetic or electrostatic effect SOLID/LIQUID OR SOLID/GAS SEPARATION Method General operations by centrifugal force using centrifuges or free-vortex apparatus using magnetic or electrostatic effect Apparatus General operations by centrifugal force using centrifuges or free-vortex apparatus , using magnetic or electrostatic effect SOLID/SOLID SEPARATION Method Dry methods material in bulk Individual sorting Screening, sifting, pneumatic sorting using pneumatic tables or jigs by magnetic or electrostatic effect by centrifugal force using centrifuges or free-vortex apparatus Wet methods General operations flotation, differential sedimentation screening Combinations Dry methods - wet methods Apparatus Dry methods material in bulk Individual sorting Screening, sifting, pneumatic sorting using pneumatic tables or jigs by magnetic or electrostatic effect by centrifugal force using centrifuges or free-vortex apparatus , Wet methods General operations flotation, differential sedimentation screening Combinations Dry methods - wet methods In this class, the following term is used with the meaning indicated: "grinding" is used in its most general sense to mean machining and covers, in particular, "corrective" operations. In this subclass, the following term is used with the meaning indicated: "polishing" means the smoothing of a surface, i.e. a surface improvement but no improvement of the dimensional accuracy as would occur in a "grinding" operation. Attention is drawn to Notes (1) and (2) following the title of subclass . GRINDING OR POLISHING PROCESSES NOT PARTICULAR TO SPECIFIC MACHINES, DEVICES OR WORK GRINDING; GENERAL FEATURES OF GRINDING, POLISHING, OR FINISHING Grinding of surfaces with simple shapes , , , Grinding of surfaces of special shape , Grinding or polishing using abrasive belts Portable machines Other machines , Component parts Measuring, indicating, controlling; Safety , ; Dressing or conditioning of grinding tools; Feeding or applying grinding, polishing or lapping agents ; POLISHING OR FINISHING Polishing, burnishing , by tumbling Honing, superfinishing , Lapping This subclass covers: the use of a blast of any particles or pellets dispersed in air, gas, or liquid for the treatment of surfaces or cutting of materials, the particles usually being of abrasive material; the equivalent use of a jet of particles or pellets projected or energised by means other than a stream of air. In this subclass, the following terms are used with the meanings indicated: "abrasive" covers any material used in the manner mentioned in Note (1) above; "blast" covers any equivalent jet of material mentioned in Note (1) above. This subclass covers grinding tools for working on any material. Tools for grinding, buffing or sharpening, specially designed for a particular purpose, which purpose is provided for in a single other place, are classified in that place, e.g. . PHYSICAL FEATURES OR CONSTITUENTS OF ABRASIVE BODIES OR SHEETS ABRASIVE WHEELS , , , FLEXIBLE ABRASIVE MATERIALS HAND TOOLS OTHER TOOLS MANUFACTURE