Development of Instrument in Order to Evaluating Weak Caking of State of Powder-Evaluation of caking of sodium bicarbonate-

摘要

Caking of powder-products in food, chemical and medical industries gives a serious economic loss if it happens during production, storage and transportation. For example, sodium bicarbonate easily forms cakes during the storage and distribution process after production due to the influence of the moisture in air, temperature, compaction and so on. Big burden is necessary in order to avoid this caking problem. Method for characterization of the weak caking is therefore required. Four types of equipment were made and examined for measuring powdering rate of clots and examined. An equipment consisting of a panting metal cylinder with lifters were finally developed. This device breaks the hardened cakes with the impact caused by rotating the cylinder for measuring the powdering rate. Strength of weak cakes can be evaluated with sufficient accuracy by using this method. Filling density of powder significantly affects on the hardening of the cakes. A new theoretical equation of powdering rate is proposed for evaluating the caking state and simulates very well the experimental process of powdering.