DETERMINATION OF THE CARRYING CAPACITY OF GRAVITY FEEDERS

摘要

Granular-material feeders have come into widespread use in the chemical industry and its related branches. The flow rate of material and the velocity of its efflux are basic parameters characterizing the carrying capacity of the feeder. They depend on the physico-mechanical characteristics of the material and the geometric parameters of the feeder. A multitude of methods exist for determination of the flow rate of gravity feeders. Some of them are founded on empirical and semi-empirical relationships, require costly experimental investigations, and are based on the assumption of constancy of the upper level to which the feeder is filled, and a steady-state flow. Moreover, the major-ity of these relationships are acceptable for a limited group of materials. The pressure and discharge velocity of material under conditions whereby flow occurs at a low feeder-fill level will depend heavily on the variation in the height of the level. The common approach to analysis of the velocity of the gravity flow of granular materials is discussed in [8-10], which are based on use of the theory of plasticity. Use of the principle of normality (plastic potential) as a result of Druck-er's stability postulate is acceptable, however, when constructing the field of strain rates only for models of materials with strain hardening.