This paper presents the study of the flow patterns inside a granular moving bed in a quasi-two-dimensional (2D) model of a granular moving bed filter (GMBF) vessel with vertical walls and a mass flow hopper. Fine quartz sand was chosen as the granular filter media in experiments. The related flow properties were measured by a Jenike Shear Tester. According to the flow properties of fine silica sand and Johanson's theory, a 2D moving-bed apparatus was built, with transparent walls and the flow-corrective insert to diminish the quasi-stagnant zones along the side walls. The flow patterns and velocity profiles of silica sand in the system with flow-corrective insert were studied experimentally, and the effect of the location of the flow-corrective insert on the internal flow patterns was investigated. The optimal placement of flow-corrective insert according to Johansson's theory was demonstrated to efficiently diminish the quasi-stagnant zones near the side walls. Little vertical shift of the flow-corrective insert from optimal position changed the stable and uniform mass flow pattern of moving bed into the funnel flow. (C) 2013 Elsevier B.V. All rights reserved.