The effect of the screen blade turbine impeller on mixing was investigated by the droplet size measurements. The droplet size was measured by using the photographic method.
A dilute solution of sebacyl chloride in carbon tetrachloride was dispersed in water by stirring in a baffled mixing tank. After stirring for a few minutes to achieve dispersion, a small quantity of agueous （70 %） hexamethylene diamine was quickly added to the water phase.
Agitation was continued for a short time （less than a minute） and then terminated. Discrete droplets (Nylon 6-10) settled to the bottom. A photograph of a random sample of encapsulated drops was made.
Discrete droplets were not formed below 200 r. p. m（impeller rotational speed）. The diameter of the droplet formed for the screen blade turbine was less than that for the flat blade turbine. In other words, the mixing effect of the screen blade turbine was superior to that of the flat blade turbine. The droplet size was ranged from 0.3 ㎜ to 3.6 ㎜. The minmum droplet diameter was 0.3 ㎜ when the impeller rotational speed was 800 r. p. m. In unbaffled tank, the diameter range of droplets was from 0.56 ㎜ to 3.60 ㎜ for the 6-flat blade turbine and 0.45 ㎜ to 2.50 ㎜ to the 6-screen blade turbine. In 4-baffled tank, it was from 0.32 ㎜ to 3.25 ㎜ for the 6-flat blade turbine and 0.30 ㎜ to 2.45 ㎜ for the 6-screen blade turbine. The fine screen blade turbine was similar to the rough screen blade turbine in both the power requirements and the droplet size.