The Screw Conveyors are also known as Auger conveyors, which works on the principle of moving the materials from one place to another. They are the basic equipment for bulk material handling. A screw conveyor works on the mechanism that uses a rotating helical screw, called “flighting”, that is installed within a tube or trough, to move liquid or granular materials. They usually consist of a trough or tube containing either a spiral blade coiled around a shaft, driven at one end and held at the other called a solid shaft screw. Other types are open helix or shaftless screws driven at one end and free at the other. The rate of volume transfer is proportional to the rotation rate of the shaft. In industrial control applications the device is often used as a variable rate feeder by varying the rotation rate of the shaft to deliver a measured rate or quantity of material into a process.
The first type of screw conveyor was the Archimedes’ screw, used since ancient times to pump irrigation water, but nowadays, our industries are becoming more and more productive and advance with the help of latest machines. The positive push has improved the industrial sector. These machines carry out major operations in the industries and have helped greatly in reducing the manual workforce. They are great of help in many bulk handling industries. Nowadays, Screw conveyors are often used horizontally or at a slight incline, providing movement. They are capable of moving semi-solid materials, including food waste, wood chips, aggregates, cereal grains, animal feed, boiler ash, meat and bone meal, municipal solid waste, etc. The screw conveyors are economical as well as, it can be accommodated in small space, allows, utilizing an inclined screw conveyor for elevating or say conveying material. The angle of inclination as per rule of thumb is 45 degrees or less, otherwise the material will end up falling backwards over the flighting and not conveying to the desired destination.
Screw conveyors are versatile and one of the most reliable cost-effective to convey wide variety range of bulk material from dry free flowing to wet sluggish dewatered biosolids.
The Screw conveyors can be designed to be operative in any of the position, whether horizontal or vertical. If properly designed, it can be economical as well as, serve the purpose for many years to come uninterrupted, increasing the productivity