In the case of conveying of bulk materials which has material characteristics like free flowing by nature, which packs under pressure, which are very light and fluffy i.e., may be windswept and materials with very high temperature, in such cases belt feeders are not suitable ; only Screw Feeder are recommended. The Gravimetric Screw Feeder is custom engineered compact, enclosed and eco-friendly equipment that finds applications in continuous bulk proportioning of solids. This gravimetric feeder operated by a closed loop control system enables feeding at a controlled rate and exercises precise control over rate of flow.

The system is capable of accepting external signals from other controllers or from the process computer, depending on the extent of plant instrumentation. These gravimetric feeders are in operation in cement, fertilizers and chemical industries. Each system consists of control panel, local panel, loadcell to measure the instantaneous load, tacho to sense the speed of the screw which is mounted inside closed trough. The screw shaft is driven by a constant speed AC motor coupled through a gear box.