GRINDING CHARACTERISTICS OF TARGET TYPE FLUID-ENERGY MILL
1980 Volume 13 Issue 3 Pages 219-225
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1980 Volume 13 Issue 3 Pages 219-225
This paper deals with the grinding characteristics of a target type fluid-energy mill, in which flying particles are ground by repeated impact on a target. The increase of specific surface area ΔSw and the distribution of particle size were investigated with respect to the following parameters: the target distance from nozzle outlet to target surface L, the target angle between air flow axis and target surface, the mixing ratio m of particles to air by weight, and the initial air pressure.
It was found that there were optimum L and m values for grinding, estimated to be 70±10 mm for L and 0.7-1.0 for m over almost all the experimental range. The energy efficiency ΔSw/Ef, defined as ΔSw per energy Ef in adiabatic expansion of air, was proportional to 1.0-1.2 power of m to m=0.7.
On the other hand, the input energy per unit products was inversely proportional to the particle size of products in the region of fine particle size, while it was independent of the particle size of products in the region of large particle size.
