インペラによる気泡の破砕

抄録

The comminutive function for the open-air bubbles on the impeller of Fahrenwald flotator is considered due to the hydraulic action of the pulp stream and the frother is said to be effective against the coalescence of reproduced air bubbles, but the comminuting strength and reduction ratio of air bubbles are not yet known- and the details of the effect of frothers are still unkown.
From this point of view the author made are exprimental studies on the above items by making use of the vertical type flowing channel consisted of cylindrical tubes, through the application of single air bubbles to water flow in the apparatus, and he obtained the following results:
1) The relationship of the equivalent diameter dmm of single air bubbles with the critical circling velocity U_ccm/sec of the impeller comminuting air bubbles can be represented by U_c=K/d^mwhere K and m stand for coefficients.
2) The ratio R of the diameter of the reproduced bubble to the original bubble can be represented by the following formula: R=d^-0.500-(2430-123d)(U-U_c) ^0.794·10^-6, where U>U_c, with a given circling velocity of the impeller.
3) The form of the bubble will not only influence on the degree of comminuting strength, but will vary the size of the reproduced air bubbles.
4) Along with the increase of the frother, the comminuting strength of the bubbles with the same diameter will be lowered (though the lowering rate is small) and simultaneously the size of the reproduced air bubbles will become smaller.
5) Accordingly high efficiency of the impeller as a pump will not essentially be great in comminutive function for air bubbles.