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 subclass covers only cleaning, which is usually classified according to one (or more) of the aspects mentioned below, if it is not fully classifiable in a subclass providing for any of the following aspects: the articles cleaned, e.g. bed-pans, urinal or other sanitary devices for bed-ridden persons , filters, semi-permeable membranes , castings and moulds , vehicles , coke ovens , building forms , boilers , combustion apparatus , furnaces ; the general nature of the cleaning, e.g. preparing for sugar manufacture , domestic cleaning , treatment of textiles , laundry , air-conditioning ; the particular operation performed, e.g. filtering , separating of solids , , sand-blasting ; the particular apparatus or device, e.g. brushes , mops , centrifuges , hand tools ; the substance cleaned, e.g. metals , , water , glass , leather , textile fibres ; the substance removed (or prevented from depositing or forming), e.g. implements or apparatus for removing dry paint from surfaces , chemical paint-removers , preventing rust ; the substance used, e.g. macromolecular compounds or compositions , anti-icing materials , detergents ; the operation in connection with which cleaning is done, e.g. metal rolling , metal boring , soldering , textile fabrication , , , ; the surroundings of a surface to be cleaned or kept clean, e.g. water in a boiler , air in a room . Processes using enzymes or micro-organisms in order to: liberate, separate or purify a pre-existing compound or composition, or to treat textiles or clean solid surfaces of materials are further classified in subclass . CLEANING CHARACTERISED BY THE MEANS USED , , , , CLEANING HOLLOW, FLEXIBLE OR DELICATE ARTICLES , ACCESSORIES OR DETAILS OF MACHINES PREVENTING FOULING OR ESCAPE OF DIRT OR FUMES ,