粉粒体の凝集性(第4報)流動性と凝集性

概要

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The six methods generally believed to be capable of estimating the flowing ability of a powder, were tested and results obtained were compared with cohesiveness (α_c), whose measurement was reported previously. Correlation was recognized between the angle of repose (θ_p, θ_d) and α_c. The values of h_o were obtained by extrapolation of height of the powder cone heap (h) to h axis, using the Train's method. Correlation between h_o and α_c seemed to exist when α_c exceeded 3. There were no relations between packed porosity (ε_p) and α_c, but a correlation was observed between Δε and α_c. In the range of α_c smaller than 2,all samples were judged as freely drainable and at α_c above 3.2,all samples was undrainable. It is concluded that the free flowing of a powder is one of the forms of flowing which can be done only by migration of the surface particle of the bed by gravitational force and, in connection with this, the definition of ability to flow freely is given as easiness to remove the particles sitting on the surface of the loosely packed powder bed. As was defined earlier, cohesiveness (α_c) is also the easiness to remove the particles sitting on the surface of the powder bed so that, in the case of the loosely packed powder bed, the ability to flow freely and cohesiveness are different manifestation of the same property of a powder bed.
公益社団法人日本薬学会の論文
1975-07-25