摘要 |
A multi-stage pressure diffuser (10) is provided for treating paper pulp or similar comminuted cellulosic fibrous material. Two different subvolumes (16, 17) are defined within the annular screen (15) of the pressure diffuser by a tubular baffle (40) hung from adjacent the top of the vessel, and a transverse wall (43) near the middle of the vessel. Wash liquid is introduced into the top stage (through 22, 23), extracted liquid passes through the bottom of the baffle, and is removed through a liquid outlet (18) at the top of the vessel. The removed liquid is then reintroduced into the bottom stage as wash liquid (through 24, 25), and the extracted liquid from the bottom stage is discharged from the vessel at the bottom (through 19). The screen assembly may be blanked at the area (15 min ) of the transverse wall (43) dividing the subvolumes from each other, in order to minimize the possibility of mixing of the extraction flows in the different stages. <IMAGE> |