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 This class covers: operations not provided for in any other class; combinations of operations covered by different subclasses of classes , which combinations are covered by subclass , with the exception of subsidiary operations performed in conjunction with main operations covered by a single subclass; features, specific to machine tools, which relate to a requirement or problem of a nature which is not peculiar to a particular kind of machine tool, e.g. feeding work, which are covered by subclass , although the realisation of these features may differ according to the kind of machine tool concerned. The said subclass covers such features, in general, even if the feature or a specific function, in any particular case, is to some extent peculiar to, or is claimed only for, machine tools designed for one particular operation; only in exceptional cases are such features classified in the subclass for the machine tool concerned. Certain features of this general nature are, however, referred to subclasses relating to particular metal-working operations, especially , in which case the subclasses in question are not restricted, in respect of those features, to the kind of machine tool with which they are primarily concerned. In this class, the following terms or expressions are used with the meanings indicated: "metal-working" covers the working of other materials unless the context requires otherwise; "kind of operations" and similar expressions relate to such metal-working operations as boring, drilling, milling and grinding; "kind of machine" means a machine designed for a particular kind of metal-working operation (e.g. a lathe); "form of machine" means a machine of a particular kind adapted or arranged for a particular way of working or for particular work, e.g. face-plate lathe, tailstock lathe, turret lathe; "different machines" covers different forms of machines for performing the same type of metal-working operation, e.g. vertical and horizontal boring machines. If details, components, or accessories have no essential feature specific to machine tools, the more general class, e.g. , takes precedence. This subclass does not cover non-mechanical operations on non-metallic materials unless such operations are specially mentioned in this subclass. In this subclass, the following expressions are used with the meanings indicated: "combined operations" excludes the assembling of parts if it is an essential feature of the next metal-working operation, since it is not regarded as an operation per se; "working of metal" and equivalent expressions include non-mechanical treatment of metal so far as it is not provided for in any other class or subclass, for example, in , , , . Thus, combinations of such non-mechanical treatment with other metal-working are classified in this subclass. Attention is drawn to the Notes following the title of class . METAL-WORKING PROCESSES Setting of diamonds Reconditioning; finishing ; Connecting or disconnecting , , Other processes , , , Auxiliary treatments COMBINED PROCESSES; MULTI-PURPOSE MACHINES Reconditioning; finishing ; Other combined operations , Auxiliary treatments