Capsule hoist system for vertical transport of coal and other mineral solids

A capsule hoist system for the vertical transport of solids in pipelines is studied. For this system a cylindrical capsule loaded with cargo is inserted into the lower end of a vertical liquid filled tube. The capsule which is of lower average density than the liquid is lifted due to natural buoyant forces. A theoretical analysis of capsule speed and system transport efficiency is carried out. The predicted results are in good agreement with a substantial number of experimental results. Of particular interest was the effect of the ratios of capsule diameter to tube diameter, capsule diameter to capsule length and average capsule density to liquid density. The principal goal of the study is to determine design factors which will maximize the rate of hoisting cargo for a particular system. It was concluded that the best ratios for capsule diameter to tube diameter and capsule density to liquid density are both approximately 2/3. It was further concluded that capsule length and the shape of the capsule nose has little influence on the efficiency of this transport system.