Patent GB-1489154-A (GB)
Title: Treatment of polluted gaseous or liquid fluids
IPC: B01D29/62
Filed: 1975-05-30
Abstract: 1489154 Centrifugal separators; electrostatic separators SOC LAB 30 May 1975 [7 June 1974] 23537/75 Headings B2J and B2P A fluid containing solid particles is whirled in an apparatus 1 about an electrode 9 having a predetermined potential in order to agglomerate the particles, fluid containing the agglomerated particles is supplied to a concentrator 17 inside which it is rotated to produce centrifugal concentration of the particles in a fraction of the fluid, a substantially particle-free fraction of fluid is extracted from the concentrator while the fraction containing the concentrated particles is diverted to a filter 30 associated with the concentrator, and fluid which has passed through the filter is recycled in the concentrator while fluid retained by the filter and containing a high concentration of particles is delivered to a collecting device. In an apparatus for treating water which comes from a washing or dust removal installation and which contains polluting solid particles, e.g. separated from, combustion gases, the water is delivered at 4 to the interior of the cylindrical body 2 of the apparatus 1 through a tangential inlet 3 to create a hollow vortex about the electrode 9 which is supported by an insulator 8 in a hollow shaft 7 at the upper end 6 of the body 2. The polarising action of the electrode causes the particles to agglomerate and they are concentrated by centrifugal force towards the wall of the body 2. Light foam moves to the free surface 5 of the vortex where it liberates gas which is discharged through a pipe 11. A water-overflow pipe is shown at 10. Water with a low concentration of particles is discharged at 14 and may either be recycled as shown by arrow 16, to the installation or it may partly or wholly be fed, with water discharged at 13 and having a high concentration of particles, to the concentrator 17. The latter consists of outer and inner coaxial cylinders 18, 19 defining an annular space in which inlet pipes 21, 22 connected respectively to outlets 13, 14 open. the pipe 21 being tangential to the wall of the cylinder 18 and the pipe 22 projecting through that wall and being tangential to the exterior of the cylinder 19. The filter 30 is mounted within the cylinder 19 and its interior is connected to a vessel 29 supported by the upper end 25 of the cylinders 18, 19 and to a central pipe 31 at the base of cylinder 18. Substantially particle free fraction is extracted from the concentrator at 26 for re-use in the installation and/or for discharge into drains. Water containing concentrated particles is discharged at 24 and is directed by a pipe 28 to the vessel 29 where it descends down the interior of the filter towards the tube 31. Water passing through the filter and flowing down the cylinder 19 is recycled in the annular space 20 via the space 32 between the lower ends of cylinders 18 and 19. The water with a high concentration of particles passes as sludge from the filter 30 and via pipes 31, 34 to a pneumatic lock chamber 33 having valves 35, 36, 38, 40, the latter being a flap valve. At the beginning of the operating cycle valves 36, 37, 38 are closed and valve 35 opened and sludge accumulates in chamber 33 raising the air pressure therein. When sufficient sludge has accumulated, valve 35 is closed and valve 37 is opened whereby sludge empties therethrough into a collecting tank. Once the chamber is empty, with entry of air through valve 40, the cycle may be repeated. If the sludge in chamber 33 is too liquid, valve 37 is kept closed and valves 36 and 38 are opened whereby compressed air introduced through valve 38 forces the sludge via valve 36 and pipe 41 to the inlet 3 of the apparatus 1 for re-cycling. The bodies 2 and 18 may be frusto-conical instead of cylindrical. In a modification the filter is provided externally of the concentrator 17 and in connection with outlet pipe 24 and inlet pipe 34.