For some processes, it is necessary to measure the different solid materials transportation flow rate involved in the process, and control them in accordance with pre- set proportion. 
Normally, LIW ( loss in weight ) method ( based on the weight loss of the material storage container ) is used to calculate the loss amount weight per unit time for determining and testing solid materials transportation flow rate. 
The key components of this special weighing and distribution control system made in our Co. are imported from foreign advanced 

countries. The instrument F850-RC controller is a kind of multiple function, wide application range intelligent weighing controller. High speed sampling by using of micro-processor, digital technology and logic calculation etc. advanced technology are used for the weight sensor signal treatment to achieve flow rate measuring, accumulation and controlling function. 
Chart No.1 indicates the system process flow chart. The independent adjustment and control for feed flow rate can be carried out individually by each set of feed facility,( the system can also be expanded for a number of materials proportional distribution ). It is also possible to form main-subordinate related operation ratio control system. 
The sensor (4) signals are continuously sampled by F850-RC (A,B,C) intelligent weighing controller. The weight loss per unit time is obtained through digital treatment and calculation, and compared with flow rate set value, to export correction signal and control screw feeder motor (7), adjust feeding materials quantities to approach intended zero deviation with set value so as to achieve quantitatively control target. 
While the materials weight in the weighing container dropped to set value, the controller will maintain some parameters no change such as feed speed no change. Through controlling actuator (8) to open the discharge gate of materials silo, the materials in the silo are quickly filled into the weighing container. While the materials in the weighing container reach the set value weight, the discharge gate is closed. The whole feed time only spends several sampling circle time, therefore, little effect exerts to the flow rate. After that, the controller is back to normal working procedure again. 
Follow customer's requirements, the whole engineering project including design, fabrication, and adjustment of solid materials continuous proportional distribution can be done by our company.