The feeder is a key component of a pneumatic conveying system, and it is the largest component that causes pressure loss. In this paper, a negative-pressure auto-feeding system was designed. Using the orthogonal design method, the effects of the airflow velocity, particle size, and feeding mass on the pick-up mass of an auto-feeding system were investigated experimentally. Based on a range analysis, the serial number for the importance of each factor to the pick-up mass was determined. The pressure in the horizontal pipeline was obtained from pressure transmitters, and the effects of the airflow velocity, particle size, and feeding mass on the airflow pressure of the auto-feeding system were investigated. By normalizing the maximum pressure signal and the material pick-up masses, the relationship between the flow field pressure signal and the crushed stone particle pick-up mass was obtained. (C) 2020 Elsevier B.V. All rights reserved.