A wide range of different feeding screw designs are used to feed bulk materials. Further adaptations are possible by varying the screw length and geometry.
Also refer to the operating principle of the screw feeder: Based on the principle of a screw, the product is conveyed through rotation in an axial direction. The designs differ to suit the application and bulk material. Slow-running mechanisms are also often used to break up and supply the material and we would recommend their use with bridging materials in particular.
There are two basic designs:
Single-shaft feeding screws: have an insignificant barrier effect. They are not suited to bulk materials which can become fluid, but are ideal for e.g. powder.
Twin-shaft feeding screws: provide a good barrier effect, making them suited to bulk materials which can become fluid and products which cling and are sticky.
Screw shapes and applications:
Full-blade screws: are particularly well suited to fine-grain to dust-grain, non-sticky bulk materials.
Belt screws: are used for fragmented and ductile bulk materials which don’t tend to stick.
Paddle screws: are perfectly suited to instances where the bulk material needs mixing as well as conveying.
Discharge screws: are ideal for discharge from e.g. silos. The screw geometry (progressive, regressive or e.g. conical) can be changed by adapting the screw length.