The discharge plug screw is used to isolate the pressure refining system from the atmospheric dilution screw at the back end and the high-concentration bleaching tower.
The discharge plug screw is similar to the side feed plug screw. The spiral of the discharge plug screw is conical, and the pulp is compressed in the conical area to form a material plug when the material plug is conveyed by the screw, which isolates the pressure area from the normal pressure area and prevents the steam from being discharged with the pulp.
The plug is continuously pushed into the T-tube. Located at the outlet of the material plug screw, a pneumatic anti-reverse injection valve is installed in the axial direction to withstand the material plug and provide back pressure to seal the system. The function of the pneumatic anti-reverse injection valve is to provide reliable sealing performance, and its control is controlled by the feedback control of the screw torque of the discharge plug.