Precision screw conveyor is also known as dual screw conveyor. It consists of main conveyor and bottom screw conveyor. The structure and performance parameters of the main conveyor are the same as for the general series. Its function is to provide fast feeding and shorten the weighing period in the early weighing period. In the late weighing period, the subcarrier works alone and is fed lightly. Its reservoir can store 40kg of material, the pipe diameter is 140mm, the material handling amount can reach 0.7kg / sec.