Working principle:

The centeral hopper loader has its own filter device, no need daily maintenance；When there is no material in the hopper loader, the material level indicator light which at the discharging port is on, and the material level switch sends the signals to the vacuum pump；
Plastic particles in the vacuum pump under the dynamic action will generate the negative pressure air flow, through the filter, so that the plastic particles in the pipeline will move and transport to the specified equipment；When plastic particles after high speed movement, arrived at the hopper loader, on the one hand, feeding port settins of the check valve under the action of negative pressure to keep open, make particles run into the hopper loader quickly, on the other hand, the check valve change feeding angle to suitable, dispersive material of high speed impact, and sharply reduce particle of the hopper loader inner wall collision sound; When the vacuum negative pressure stops(or the vacuum suction valve stops), the check valve is affected by gravity and closed the feeding port； The gravity valve at the diacharge port of the hopper loader opens quickly because there is no vacuum suction, and the raw material drops down from the hopper loader to the corresponding equipment.