| 摘要 |
Process for filtration of liqs. uses disc type filter elements mounted on a rotatable shaft. It has the following features:- i) the filter elements are slowly rotated during filtration, ii) at the end of the filtration cycle the residual slurry in the filter chamber is removed by the primary filter pump and fed to an auxiliary filter. iii) the solids which collect as a cake on the filter elements in a semidry state are removed by rapid rotation of the shaft, iv) finally after this mechanical removal, the residues are washed out by clean liquid. This liquid is finally filtered through the auxiliary filter by means of the primary filter pump. The elements consist of circular discs mounted inside a chamber which can be taken back. The collection shaft is coupled to a motor and the unit has a pump to meter in an auxiliary fluid contg. filter aid and a vessel to contain this. Process is useful for filtration processes where generally filter aids are used. Filter aids improve the filtration properties of a slurry. However when the cake is ultimately removed by a back flushing operation, the liquor is heavily contaminated and if discharged to an effluent stream causes blockages, contamination, respiratory dangers etc. A further problem is that cake growth is not uniform and the process does not permit the recovery of the cake in a reasonably dry condition. The filter described overcomes these problems. |
