Screw Press, also named Fold Screw Sludge dehydrator.which uses the screw extrusion principle is to realize solid liquid separation .The main body is made of multiple fixed annular plates and moveable annular plates with the screw shaft running through it,The front part is thickening department and the ending part is dewatering department. Sludge will be transported to the dewatering department after being thickened in the thickening department. In the advancing process, great pressure has been produced because of the gradually decreasing filter spacing and screw distance, and the back platen clogging. Then the volume decreases continuously, and the purpose of fully dewatering will be achieved.filtrate will be discharged from joint of fixed annular plates and moveable annular plates and cake discharged from the end of dewatering department.

Screw Press is mainly used in wastewater treatment industries，such as ：municipal wastewater，wastewater from food,beverage，chemical，leather industries etc., especially for the sludge contain oil.