Blanking and weighing device in full-automatic sample preparation system

A discharging and weighing device in a full-automatic sample preparation system comprises a machine frame, a middle hopper and a bidirectional belt conveyor are installed on the machine frame, the bidirectional belt conveyor is connected with a driving motor, the middle hopper is a four-edge conical hopper, the bidirectional belt conveyor is fixedly installed below the four-edge conical hopper, the bidirectional belt conveyor comprises a bottom frame, and the bottom frame is connected with the driving motor. Four weighing sensors are installed between the bottom frame and the machine frame, the weighing sensors are connected to a controller, the front side face and the rear side face of the four-edge conical hopper are each provided with a pneumatic vibrator, stirring shafts are rotatably installed on the left side face and the right side face of the four-edge conical hopper, a plurality of stirring rods are fixedly connected to the stirring shafts, and the stirring rods are connected to the controller. And t