Movement of bulk material is an essential feature in modern industrial processes. The simplest and fastest mode of transportation of such material is to convey them over a moving belt. In this operation the precise weighing of material, as it moves, has assumed a key role in process industries. Hence weigh feeder is a closed loop control system in which a precise control can be had over the flow of materials, which has indicating, totalizing and controlling instruments and circuits.

Every process industry be it steel, pharmaceuticals, food, chemicals etc would need to do batch production in certain processes. This would be due to processes like mixing, reactions etc. It is then so desired that certain quantities of different ingredients are put together as a batch and the recepie is critical for the process. The system should ensure that only the right quantity of the ingredient is discharged to make the batch. The system would comprise of loadcells, gates, control desk which houses a PLC and the SCADA software. The sequence of operation can be customized for the process. Batching systems ensure that there is efficient process control in terms of the quality of end product, reduction of physical labor and the error arising due to the same, improved productivity and a cleaner factory.

Loss in-Weigh Feeders operate on the principle of controlled loss-in-weight. The proposed system comprises of a Weigh Hopper, Loadcells, Screw Conveyor with motor and associated control electronics. The Weigh Hopper and Screw Conveyor are mounted on 3 Nos. of Loadcells. The Loadcells are connected to a controller through a junction box.

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.

These metering devices are used to measure the flow rate of very fine particles like fly ash, cement etc. The material flows by gravity through an air slide and flows over a plate which measures the impact which is proportional to the density of the material and the flow rate. The impact on the plate is measured by two high precision loadcells that give a very linear output proportional to the flow rate. The output of the loadcells are fed into the micro controller based flow rate indicator which gives the rate and totalized quantity of material.

The system finds extensive use in process industries where monitoring the quantity of materials coming out after completion of a process, especially where materials like powder, granules etc. are used, which comes out at a very low rate, say in the order of under 5T per day or lesser. It is extensively used in the tea industry.