Pan coating apparatus with louvered air supply guide

An apparatus for applying coating to a powdery or granular material, comprising:

• a rotary drum supported rotatably about a substantially horizontal axis, a coating chamber being defined inside the rotary drum;
• a plurality of air ducts provided on an outer periphery of said rotary drum in an axial direction and communicating with said coating chamber through air holes formed in said rotary drum, respectively;
• a liquid spraying means disposed within said rotary drum for spraying a liquid onto a layer of the powdery or granular material accumulated on a bottom portion of said rotary drum;
• an air supply duct connected to said rotary drum for supplying a gas into said rotary drum, the air supply duct being provided with an outlet opening positioned at an end portion of said coating chamber;
• an air exhaust duct disposed at a lower portion of said rotary drum for exhausting the gas in the rotary drum through said air holes, the air exhaust duct communicating with an air duct positioned at an under side of an accumulated layer of the powdery or granulated material in accordance with the rotating position of said rotary drum out of the plurality of air ducts;
• and
• a guide member formed of louvers or a plurality of plate members provided at said outlet opening, for guiding the gas supplied from said air supply duct toward the bottom portion of said rotary drum toward said accumulated layer of the powder or granulated material.