Improved pressure screening system

The pressure screening system of the pulp containing impurities includes a pressure screen for purifying the pulp containing the impurities, and a high tank for generating the feed pressure head. There is a floatation section in the high tank, and the slurry and the air enter the section together. The air generates air bubbles, separates impurities and overflows from the pulp, so that good fibers in the slurry can be recovered, air enters the flotation section with the slurry, or air is mixed before entering the flotation section. High tank with flotation section can accept slurry discharged from multi-stage pressure screen, or a separate high tank only corresponds to a section of pressure screen, improved system to reduce fiber loss in pulp, reduce equipment investment, reduce traditional high tank and slurry treatment For the complexity of the distribution, the flotation part is preferably in the form of a riser connected to the upper tank, or a separate flotation cell, connected to the upper tank via a pump or valve.