System for feeding granulated substance and feeding method used therein

A feeding system of a granulated substance, comprising:

• a feeding path configured to feed, toward a use machine that uses a granulated substance, the granulated substance together with a carrying airflow;
• a separation device configured to, in a feeding process of the granulated substance, separate the granulated substance into a good product and a sub-standard product heavier than the good product by separation through winnowing, and discharge only the sub-standard product from the feeding path;
• an adjustment device capable of adjusting a flow velocity of a sorting airflow to be used for the separation through winnowing;
• a transfer path configured to receive and transfer a sub-standard product discharged from the feeding path;
• a weighing device configured to sample the sub-standard product transferred through the transfer path at a predetermined timing and for a predetermined period, perform weighing of a sampling weight of the sub-standard product and output of a weighing result of the weighing, and then return the sampled sub-standard product to the transfer path;
• and
• a controller configured to receive the weighing result from the weighing device, and, based on the weighing result, control an operation of the adjustment device to bring the sampling weight equal to a target value of a management standard,
• wherein the adjustment device is capable of adjusting the flow velocity of the sorting airflow by changing the opening degree of the feeding path.