Patent EP-2138463-A2 (EP)
Inventor: RUESE STEFFEN
IPC: B05B14/462
Filed: 2009-06-23
Abstract: The method for separating solids in a system basin (1) of a varnish system, comprises transferring air-water mixture, which contains roughly and/or finely dispersed solid portion with predetermined volume flow rate (V(E)), from a varnishing cabin into the system basin in which the physical separation of solid and liquid medium (2) takes place over floatation. Currents are produced in the system basin at the points (A n) and are adjusted, so that the ratio of the flow velocity (gamma 0) on the surface at the point in the basin to the theoretical average flow velocity (gamma m) is greater than 3:2. The method for separating solids in a system basin (1) of a varnish system, comprises transferring air-water mixture, which contains roughly and/or finely dispersed solid portion with predetermined volume flow rate (V(E)), from a varnishing cabin into the system basin in which the physical separation of solid and liquid medium (2) takes place over floatation. Currents are produced in the system basin at the points (A n) and are adjusted, so that the ratio of the flow velocity (gamma 0) on the surface at the point in the system basin, in which the liquid medium enriched to solid is continuously removed with the predetermined volume flow rate (V(K)), to the theoretical average flow velocity (gamma m) is greater than 3:2. The tapping point is arranged in a predominating flow direction behind the points (A n), at which the currents are produced, for the volume flow rate (V(K)) during the liquid medium enriched to solid is continuously fed back with a volume flow rate (V(A)) into the varnishing cabin, in which the liquid medium enriched to solid and optionally further part of water with the solid and air to be separated are mixed to the air-water mixture and then transferred into the system basin with the volume flow rate (V(E)). The partially opposing currents are produced at the points (A n) of the predominating flow direction for the adjustment of the ratio of the flow velocity (gamma 0) to the theoretical average flow velocity (gamma m) when the ratio of the flow velocity is greater than 5:1 without the influence of the produced currents at the points (A n), or the partially adjacent currents are produced at the points (A n) of the predominating flow direction when the ratio of the flow velocity is less than 3:2 without the influence of the produced currents at the points (A n). The tapping point for the volume flow rate (V(A)) of the liquid medium enriched to solid is arranged in the predominating flow direction behind the tapping point for volume flow rate (V(K)) for the removal of the liquid medium enriched to solid in the system basin and presents itself at the front surface of the system basin, which lies opposite to the tapping point at the inlet of the system basin. The currents at the points (A n) are not produced below the inlet point (5) of the volume flow rate (V(E)) in the system basin at the respective points (A n). The distance between the points at which the air-water mixture enters into the system basin and the respective points at which the flow direction of the partially opposing or adjacent current is produced, is less than three of the length of the system basin in the flow direction. The partially opposing or adjacent current is produced by a continuous-flow machine that receives a mechanical work and delivers in the form of flow energy to the liquid medium surrounding it. The agitators, propeller, impeller and/or centrifugal pumps (3, 4) are used as continuous-flow machine. The respective continuous-flow machine produces a current of the air-water mixture, which is partially opposed or adjacent to the flow direction in the system basin, in the respective point (A n) over an entrance to the outside air. The flow rates (V(E)), (V(A)) and (V(K)) are equal to zero and the currents of the air-water mixture are adjusted mixtures at the respective points (A n), so that the dissolved oxygen content in the system basin does not reduce below a predetermined value of 6 mg/l O 2.