ZNV series screw press washer consists of press screw, discharge controller,filter drum, inlet hopper, vat, end bracket and driving device, etc. Pulp is fed into the screw press washer through the hopper. When the rotating roll revolves, the stock passes from feeding section to the pressing section and then to outlet. The stock, filter drum and rotating roll press and glide one another. Affected by screw thrust along the direction of the axis at a certain thickening ratio and counterpressure from the outlet controller, the stock is pressed and dewatered through the nearby filter drum. The water squeezed out of the stock flows into the save-all pan and discharges at water outlet. The thickened pulp is discharged at pulp outlet.With pneumatic discharging controller, the outlet consistency can be controlled by regulating the cylinder's pressure so as to thicken the inlet pulp with the consistency of 3~12% to 28~30%.As the screw roll is driven by the driving device consisting of reducer and V-belt, the process of pressing and thickening can be ensured stable and smooth.With its simple structure and anti-slip mechanism mounted on the filter drum, the press washer can work more reliably. It is easier and safer to operate and maintain.