This paper is concerned with the interfacing of a rotary valve to mass-flow axi-symmetric bins with conical hoppers. A model feeder and hopper system, constructed from perspex, is described, the rotary valve having six vanes and being driven by a variable speed motor. Two hopper half angles are examined in the mass-flow bins, namely 15 deg and 20 deg. The experiments involve the application of an 'impulse' layer of marked particles on the surface of the solids in the bin and determination of the 'volumetric weighting function h(V)' of the bin and rotary valve system for a range of valve speeds. From the shape of the h(V) distribution, the blending performance on the one hand, and anti-segregation characteristics on the other, can be determined. The results identify the range of valve speeds over which non-mixing and anti-segregation occurs, and the range of speeds necessary if mixing and blending are to be effected. Procedures for optimising the design of hoppers and rotary valves to achieve desired flow patterns, and blending or anti-segregation, are outlined.
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