Our Screw conveyors were used as low height lift pump to irrigate the lands. It comprises of an incline drotating casing with an internal helical screw thread, called flight. When sucha casing is rotated with its lower end submerged in water, the water entraine din the pockets, formed by the pitches, is raised. The performance of such screws is limited by the angle of inclination of the casing. A modified version of such screws have been tried wit a rotating shaft having helical screw thread moving inside a stationery casing for lifting fluids like sewage sludge.But due to various limitations the process achieved limited h success in the field of transportation of liquid. However when a rotating screw shaft in astationery casing is used to convey solids, it has commendable success.
Floor mill industry was probably the first to employ horizontal screw conveyor to convey corn and flour. These screws were made by fitted wood blades to a central shaft rotating inside a cylindrical casing. Even now such screw conveyors enjoy popularity in agro based industries, handling grains and flours, because of low friction,negligible cohesive strength of the material.