The invention relates to an air flow screening device for micron-sized
powder materials, belonging to the screening technical field of
powder engineering. The device is formed by improving the existing boiling dryer as follows: a front exhaust main
pipe of the existing dryer is divided into a front exhaust main
pipe and a back exhaust main
pipe, a
sieve plate mesh box with a
sieve inside is added between the front exhaust main pipe and the back exhaust main pipe to increase the space dimensions of a fluid
bed so as to increase the area of the
sieve, so that the effective drift
diameter of the sieve is increased, and the
pore diameter of the sieve can be changed; a blowback device is added to prevent the sieve from being clogged; a circulating device is added to circulate the
powder back to the main cavity of the fluid
bed; and a pneumatic transmitting and discharging device is added on the basis of the original exhaust
system. The device overcomes the defects that the existing boiling dryer can be only used for
millimeter-sized particle materials due to the small sieve area and large meshes of the existing boiling dryer and powder materials are piled on the sieve and clog the sieve to block or even disable the air exhaust so as to affect the normal operation of the air jet screening when a small-pore sieve is used in the existing boiling drier. And the invention is applicable to the screening of powder materials.