Weigh‐feeders are used to feed bulk solids at a controlled rate into the process. Rugged design makes them ideally suited for use under adverse conditions. As the variable speedpre‐feeder feeds product onto the synchronous speed weigh belt, the weight of this material is instantaneously sensed and transmitted to the feeder& controller. In turn, the controller modulates the variable speed drive of the pre‐feeder to maintain the precise feed rate as selected. A closed-loop PID control system ensures precise control over the rate of flow of material. The system consists of a Control Panel, Load Cells, and an Optical Encoder. The weigh‐feeder is a programmable electronic system, which interfaces to Load Cell and Encoder. It calculates the rate of the measured belt load and belt speed.