To provide an inexpensive pneumatic classifier capable of mechanically classifying a heavy material and a middle light material in waste, prevented from incorporating the light material into a heavy material settling chamber due to turning back wind or turbulence and high is classification efficiency. 廃棄物中の重量物と中軽量物とを機械的に選別するとともに、巻き戻りの風や乱流により軽量物が重量物沈降室内に取り込まれるのを防止し、選別効率が高く、かつ安価な風力選別機を提供する。 - 特許庁