抄録
The gravitationl size classification of particles was carried out under reduced pressure using an air elutriator. This method was attemped to improve the performance paying attention to see if the effect of the slip factor in the ‘Cunningham correction’ increased with decreasing pressure.
The performance under reduced pressure was much better that that under atmospheric pressure. It was found that the cut size varied according to the operating pressure. The cut size under reduced pressure could by estimated from the equation of the terminal velocity of a particle, including the Cunningham correction. The partial separation efficiency under reduced pressure agreed well with the calculated values.
