Metering Systems For Solids

The lost weight scale is a weighing device that intermittently feeds materials while continuously discharging them. Since weight loss control occurs within the hopper, it achieves higher precision and easier sealing, representing a significant improvement over screw scales in controlling fine powders like cement, lime powder, and coal powder. It is suitable for precise batching of micro-materials. Composition of the Lost Weight Scale Batching System The system consists of a weighing hopper, feeders (screw feeders, electro-vibrators, or belts), measuring instruments, electrical control components, and computer monitoring systems. Working Principle The system controls the discharge screw or electro-vibrator based on the material weight loss rate in the hopper to achieve precise batching. When the hopper reaches the lower weighing limit, the discharge screw maintains a fixed output rate while rapidly transferring material from the hopper into the weighing hopper. Loading stops when reaching the upper limit, with rapid loading shortening feeding time and improving weighing accuracy. Product Description The system measures complete feeding units (hoppers, feeders, and bulk materials) using static scales, while controlling bulk material discharge flow through variable-speed motors or electro-vibrators. Materials discharged through screws, vibrating tubes, or troughs are compared against preset "lost weight" values (measured in dv/dt) and required feed rates. The controller generates correction signals based on discrepancies between actual and expected flow rates, automatically adjusting feeding speed to maintain precise quantities without process lag. When the measured weight in the hopper reaches the low material level (triggering refilling), the controller initiates volumetric feeding control for the feeding system, enabling rapid hopper refilling (manual or automatic) and reactivating the weight loss controller. While the batch weighing weight loss system shares similar design principles with continuous weight loss systems, its feeding cycle's final weight accuracy surpasses actual feeding quantity control. The controller first provides high-feeding signals to the variable-speed drive for rapid feeding, then switches to low-feeding control signals to ensure precise control at batch completion.