Screw (Auger Shaft)

The screw — also called the auger or shaft — is the heart of the screw press. It rotates slowly (typically 0.5–5 rpm) inside the cylindrical filtration screen, transporting conditioned sludge from the inlet toward the discharge end while progressively increasing pressure. The shaft diameter increases and the flight pitch decreases along its length, reducing the internal volume. This gradual compression squeezes water out of the sludge through the surrounding screen, producing a progressively drier cake toward the outlet.