Powder classifying apparatus

A powder classifying apparatus for classifying powder having a particle size distribution to collect fine powder having a size not larger than a predetermined particle size, comprising:

• a casing including two disk members arranged to be spaced apart at a predetermined interval and a peripheral wall member attached on outer peripheral sides of the two disk members, the casing having therein a disk cavity formed between the two disk members and at an inner side of the peripheral wall member, the disk cavity being a place where the powder is classified by a whirling gas stream generated therein;
• one or more powder supply ports disposed at an outside of at least one of the two disk members of the casing so as to communicate with an inner side of an outer edge portion of the disk cavity, and configured to supply the powder conveyed by air flow into the disk cavity;
• a discharge section formed at at least one of the two disk members of the casing so as to communicate with a central portion, in a radial direction, of the disk cavity, and configured to discharge air containing the fine powder to be discharged from the disk cavity;
• a collecting section formed at a middle portion, in a thickness direction, of the peripheral wall member of the casing so as to communicate with the outer edge portion of the disk cavity, and including a slit-type opening provided to collect coarse powder having a size larger than the predetermined particle size to be discharged from the disk cavity;
• and
• two air introducing sections separately provided at opposite sides, in the thickness direction, of the slit-type opening of the peripheral wall member of the casing, each including a plurality of air introducing devices arranged at the peripheral wall member of the casing at the outer edge portion of the disk cavity to extend along tangential directions of the outer edge portion, the plurality of air introducing devices being configured to introduce air into the disk cavity to generate the whirling gas stream in the disk cavity.