| 摘要 |
A pressure diffuser includes in a liquid-tight pressurized vessel a vertical screen and which screen and vessel wall define first and second interior volumes for transmitting pulp from a pulp inlet to a pulp outlet and receiving displacement (e.g. wash or bleach) liquid transmitted from headers through the pulp. The screen ends have different cross-sectional areas, and quick movement of the screen effects backflushing. The volumes are segregated by a vertical, generally cylindrical, screen. A chamber is provided in communication on opposite sides of a piston therein with the pulp adjacent the pulp inlet and the extracted liquid. By displacing the piston immediately prior to rapidly moving the screen vertically to effect backflushing through the screen, the pulp pressure on the screen is being reduced and at the same time a volume is made available adjacent the pulp inlet in the chamber thus avoiding pressure shocks and compaction of the pulp adjacent the inlet caused by the movement of the screen. |
