Abstract: A pre-filtering apparatus for pre-filtering raw material to be pressed by a continuous screw press having a hopper includes a filtering screen arranged rotatably within the hopper about a shaft, so that the inside space of the hopper is divided into two portions. The raw material is supplied into the one of the two portions which communicates with the continuous screw press. Water, oils and fats extracted by the screen from the raw material are discharged out of the hopper through an outlet pipe provided to the hopper at a position above the shaft.

Abstract: In a continuous press of a screw blade type, a driving shaft is rotatably secured to a frame by means of thrust bearings at both ends of the driving shaft, a screw drum having an increasing diameter towards center is disposed around the driving shaft to rotate therewith, a pair of screw blades are helically arranged around the screw drum symmetrically with respect to the center of screw drum, and an outer drum having a number of small filtering holes is arranged around the screw blades. A pair of inlets for introducing raw materials to be pressed are provided at both ends of the outer drum and an outlet from which the pressed raw materials are discharged is also provided in the outer drum at its center. Since repelling forces applied to the screw blades are cancelled each other, no thrust force is applied to the driving shaft and the bearing.

Abstract: A continuous press of a screw press type for pressing water, oils and fats out of sludges of paper pulp, fish scraps, etc. comprises a rotatable screw shaft, a screw drum secured to said screw shaft, a screw blade spirally arranged on the outer surface of said screw drum, an outer drum having a number of filtering small holes, an inlet for introducing raw materials to be pressed into a space between the screw drum and outer drum and an outlet for discharging pressed materials. The continuous press further comprises means for heating the screw drum and blade from the inside of the screw drum through said screw shaft.