空気圧が作用した排出管付ホッパからの混合粉体の流量に関する実験的研究

Abstract

An experimental study was carried out in which an efflux tube is attached vertically to the efflux orifice of a hopper, and the flow rate of powders flowing out of the tube and the pressure in a tube are controlled. The air from a compressor is blown into the tube, and its position is fixed directly below the orifice. As samples, mixed powders, i. e., the same kinds of powders having different particle diameters (glass beads), different kinds of powders having the same particle diameters (glass beads and styrol resin) and additives of a flow-improving agent, talc to glass beads are used. A flow rate of powders and the pressure distribution in a tube are measured for various combinations with volumetric flow rates of air and mixing ratios of powders or additive rates of talc.It was found that a flow rate decreases if the volumetric flow rate of air increases, and their relationships become nearly a straight line both in the uniform down-flow state and in the discontinuous state for all samples and when tho gradients of those straight lines are affected by the mixing ratios and the additive rate of talc. The curve shapes of the pressure distribution differ with the volumetric flow rate of air, and its minimum values exist. The positions of these minimum values shift upward if the volumetric flow rate of air increases and differ with the kinds as well as with the mixing ratios of the powders and the additive rate of talc.