Abstract: A slit-tube filter has a hollow cylindrical filter element of bent wires which are attached to vertical retaining supports and form horizontal slits between themselves through which the liquid to be filtered passes, the cylindrical inner wall of the filter elements forming the filter surface adjacent the flow of liquid. The liquid flows from the inside of the filter element to the outside. A stripping device passes over the filter surface adjacent the flow of liquid, and bears against the inner wall of the cylinder. The stripping device is a coaxial helix of brushes which rotates in relation to the filter element in a direction such that the suspended and settleable solids disposed on and in front of the filter surface are conveyed downwards.

Abstract: The present invention relates to a filter cleaning device, preferably for the cleaning of gases, such as welding fumes. To provide a filter cleaning device which efficiently cleans the filter without need for dismounting it, the filter cleaning device comprises at least one rotary filter (10) with outwardly directed projections (17), and at least one impeding device (12) which upon rotation of the filter (10) causes the projections (17) to give way and permits them to revert, whereby a shaking movement is imparted to the projections (17) to make them shake off the impurities adhering to them and toss the impurities aside by the action of the rotation of the filter (10).

Abstract: In an extraction method and apparatus for extracting low biomass solid materials from a pneumatic transport line, the stream of gas having the solids entrained therein is caused to flow over a toothed extractor wheel. The toothed wheel picks out of the stream the solid materials which are then doffed from the tooth extractor wheel by the vanes of a rotating valve which seals the pressure of the pneumatic transport line from the ambient. The material doffed from the extractor wheel falls into the region between the vanes of the rotary valve and is then removed from the system as the vanes of the valve rotate. The air stream which is inducted into the extractor is first caused to pass through a diffuser which slows the velocity of the air stream and then the air stream is cause to flow along a curved duct section toward the extractor wheel causing the solid materials to flow to the outside of the curved duct section and into the extractor wheel to facilitate extraction.

Abstract: A self-cleaning paper trap for use within a dust control system and mounted in the duct to trap sheet materials. The paper trap includes a housing which carries a plurality of spaced grid bars to trap the sheet materials and a wiper bar which is vertically reciprocal relative to the grid bars to wipe trapped sheet materials from the bars. An automatic cable control apparatus is operatively engaged with the wiper bar to permit remote wiper bar actuation without the need for system shut-down.

Abstract: A filter medium for use in a vacuum cleaner is shown with external brush means which is movable across the filter face for cleaning the soil therefrom. The brush means may either be moved manually, by automatic controls, by time switches, by pressure differentials operating in a piston-cylinder arrangement, or by a pressure indicator unit which monitors the clogging condition of the filter. Moreover, control means are provided for protecting the vacuum cleaner drive motor from damage from liquids when liquids may be drawn into the vacuum cleaner.

Abstract: A filtering apparatus for filtering a fluid comprises two coaxial walls which are provided with openings for the radially-outward passage of the fluid to be filtered, granular filtering material being disposed between the walls. The fluid to be filtered is fed into the space bounded by the inner wall and the filtered fluid is abstracted from an annular chamber disposed about the outer wall. The inner wall is formed from a series of annular inclined vanes. A rotary shaft disposed coaxially within the inner wall carries blades which project between the vanes. The blades scrape deposited matter from the vanes and also scrape the radially innermost parts of the granular filter material from between the vanes. In accordance with the method of the invention, the filter material is emptied periodically from between the walls and this emptied material and the material removed by the blades is carried to a treating station for regeneration and re-cycling to the upper end of the space between the walls.