Although generally considered as simple, slow moving mechanical dewatering devices, screw presses can come in a variety of designs for many agricultural based applications. In its simplest form, the unit consists of an inner screw that conveys product forward through the machine and an outer basket or cylinder that allows the passage of fluid for dewatering - all enclosed in a housing. Different applications will have different styles of screws and there may also be internal extraction plates within the unit.
Over time these units do require rebuilding as the transfer screw and screen surfaces will wear, resulting in a wetter output or the passing of too many solids into the liquid filtrate stream. A rebuild may include elements such as: