The parameters of impact sound due to collision between a circular plate and a particle are investigate in order to apply it to monitoring for a powder industrial process.
The waveform of the impact force between a circular plate and a particle is calculated on the basis of the Hertzian theory. The maximum impact force is proportional to the impact velocity of a particle. Furthermore, it is shown that the component more than characteristic frequency decreased in frequency spectrum of the impact force, and the characteristic frequency depends on the diameter of the impact particle. The vibration equation of circular plate is linear, and the parameters of impact sound are also related to the impact velocity and particle diameter.
These results show that the diameter and impact velocity of a particle can be measured by the analysis of impact sound from the collision wall of equipment and particles.

View full abstract

The application of the 3-parametric adsorption equation to N₂-adsorption isotherms on non-porous powders, two kinds of TiO₂ and Al₂O₃ which were confirmed to be a non-existent micropore due to α_s-plots was investigated in comparison with the adaptability of the BET equation to these isotherms and by the comparison of the surface areas due to respective adsorption equation, outerplane surface areas due to α_s-plots, surface areas using the SEM method and the flow method with those due to the adsorption method. The surface areas due to each adsorption equation agreed with each other within 20%, irrespective of its derivation on different bases. The outerplane surface areas and surface areas due to the SEM and flow methods agreed with those from the adsorption method within 20% too. Thus, it is undecided which is a reasonable adsorption equation to obtain the reasonable surface areas. However, the BET equation agreed with the experimental adsorption isotherms in the range of relative pressure from 0.05 to 0.3 at which the monolayer was completed and in the upper range of the relative pressure of 0.3, the equation predicts a steep increase in the amount adsorbed more than that of the experimental isotherms. The 3-parametric adsorption equation agreed with experimental ones in a wider range of from 0.05 to 0.6 or 0.7 more than that of the BET equation. Since the latter equation showed an agreement in the relative pressure range higher than 0.3 in which the monolayer was completed, the upper adphase over the monolayer was conceived to be formed not by a stacked layer as in the BET model but rather by the mobile adphase on the basis of a 3-parametric adsorption equation.

View full abstract