Air diffusion device

An air diffusion device comprising:

• a base coupled to an air supply pipe for supply of air, the base having an air discharge hole for discharge of air supplied from the air supply pipe;
• a perforated cover in the form of a multi-layered stepped plate, the height of which is reduced stepwise from the center to the edge, the perforated cover having a plurality of through-holes for discharge of air, the perforated cover being coupled to an upper surface of the base to cover the air discharge hole, thus defining an air guide chamber between the perforated cover and the base;
• and
• a securing mechanism configured to secure the perforated cover to the base,
• wherein the base is provided at an upper edge thereof with a cover bonding portion coming into close contact with the perforated cover, and the perforated cover is provided at a lower edge thereof with a base bonding portion coming into close contact with the cover bonding portion, and
• wherein the securing mechanism includes a securing ring coupled to the upper edge of the base to cover both the upper edge of the base and the lower edge of the perforated cover, and a cover pressure portion protruding downward from the securing ring to push the lower edge of the perforated cover to the upper edge of the base.