Counter-impact jet milling mechanism and jet mill using the same

A counter-impact jet milling mechanism, comprising:

• a substantially cylindrical housing having opposite sides, and an inner wall connecting the sides, a material inlet and a material outlet are formed in the housing;
• an impeller with a plurality of rotating members is mounted for rotation in the housing, each rotating member has multiple negative pressure blades formed thereon for producing multiple negative pressure zones between the negative pressure blades and multiple positive pressure blades formed thereon for producing multiple positive pressure zones between the positive pressure blades, the pressure blades define at least four grinding areas each distributed circumferentially about the rotating member;
• a channel is formed between each of the grinding areas and the inner wall of the housing;
• and
• a through path formed at opposite ends of each of the channels, connects respectively, a negative pressure zone and a positive pressure zone;
• wherein
• each of the negative pressure blades and each of the positive pressure blades has a straight portion and an arcuate portion, and upon rotation of the impeller, the arcuate portions of the pressure blades divert material-containing air to flow into and out of corresponding grinding areas sequentially in one direction by way of a corresponding negative pressure zone and in another direction by way of a corresponding positive pressure zone to define a two-phase flow.