| 摘要 |
996,717. Adding filter aid; filter presses. U. PASSAVANT, and P. SCHRAMM, [trading as PASSAVANT-WERKE]. Aug. 6, 1963 [Aug. 4, 1962], No. 31010/63. Heading B1D. Filter aid such as ash from a bunker 2 is first dosed at 1 into a water tank 3. Filtrate from the reservoir 5 of a filter press 22 is pumped (4) into the tank via conduit 6 after ash feed has ceased. Eventually the rising liquid acts on floats 10 to close ash pipe 9 by flap 8. Thereafter, liquid flowing out at 11 into a vessel 15 contacts an electrode 13 to effect switching off of pump 4 and closure of valve 12. These stages occur during a filtration stage in the press 22. When a new filtration stage is about to start, and a manometer in the press closure hydraulic circuit indicates that the closure pressure has been reached, a control elements effects opening of a valve 17 in a conduit 20 leading from a compressed air reservoir 27 to jets 19 in tank 3. Filter aid suspension is thereby forced up a conduit 23 past a check valve 24 and into the sludge inlet conduit 21 of the press, so as to be discharged on to the filter medium at a speed of flow corresponding to a multiple of the sedimentation speed of the filter aid. Valve 17 is then closed and sludge is fed to the press. |
