The core of the negative pressure conveying system is the suction machine with the suction hopper. Its control center is equipped with a microcomputer, which controls the suction and discharge time, and is equipped with high material level alarm and material discontinuous time. An optional rear-mounted cyclone filter is suitable for processing brittle or heavily powdery materials to ensure smooth conveying without material clogging. For systems that start frequently, a motor non-stop valve can be incorporated to extend the service life of the motor.