Successful feeding is critical to biomass utilization processes such as pyrolysis liquefaction or gasification. The biomass particles in hopper frequently become bridge or adhere to the wall to prevent the feeding system from providing the required uniform and continuous flow of feedstocks. To solve the problem, an automatic shake mechanism was devised which was set in the hopper and driven by the rotation of screw. Experiments were done using the automatic shake mechanism to feed three kinds of sawdust; the total torque requirement of the screw feeder with the automatic shake mechanism in the hopper was predicted and compared with experiment results. The results showed that the biomass particles could be delivered uniformly and the feeding rate had a significant increase with 7% extra power consumption. (C) 2010 Elsevier B.V. All rights reserved.