Screw conveyor systems are materials handling machines that transport materials through a conveyance channel by using a rotating screw. When the screw is turned by a motor, the material loaded into the channel is moved through the channel until it is discharged through an outlet.
Screw conveyor systems are designed to transport small grained materials, such as grain and plastic pellets used in injection molding. Screw conveyors are better suited to the transportation of small, powdered or granulated materials because they can completely enclose the materials they convey. Belted conveyors, on the other hand, are often not as appropriate for the transportation of such materials; powdered substances can become ground into conveyor belting, and they can also escape the conveyor belt and accumulate in conveyor components, such as rollers and gears. Screw conveyors are also valuable because they are capable of conveying materials to higher levels. Vertical screw conveyors, for example, convey materials straight up, while inclined screw conveyors raise materials at an angle. Some screw conveyors are modular or portable; in many cases, these portable conveyors are also flexible, which allows them to be used for the movement and deposit of materials in many different contexts.
Depending on the application, screw conveyors may be fitted with a variable rate feeder to control the amount of product distributed while in use. Unlike traditional belt conveyors, screw conveyors are capable of transporting liquid products. However, they are not as efficient as other fluid moving methods. They are more commonly used for the transportation of dry and semi-dry materials. Screw conveyor systems are widely used in agricultural applications. Industrial users of screw conveyors refer to the equipment as auger conveyors, helix conveyors and many other names. All screw conveyors feature a conveyance channel, a rotating screw and an inlet and outlet. The material to be conveyed is drawn in through the inlet, forced upward by the turning screw and discharged through the outlet. The outlet can be positioned over a storage silo, shipping vehicle, hopper or other appropriate receptacle. In the case of plastic thermoforming processes, for example, screw conveyors can be used to deposit plastic pellets into hoppers suspended above extruders or injection molders. Screw conveyors are so widely used because they are versatile and reliable.
