Spray dryer

An improved spray dryer for transforming a liquid feed solution into a dry powder comprising:

• means for supplying a continuous flow of the air required for drying;
• means for heating the flow of drying air to a desired, relatively high temperature;
• a drying chamber for receiving dispersed, small droplets of the feed solution and wherein the droplets are transformed into dry particles;
• an air distribution system which is connected with the air supply means and which directs the flow of drying air into the drying chamber so that the air flowing into the drying chamber has substantially uniform temperature and velocity profiles;
• an atomizing system which forms and introduces the dispersed droplets of feed solution into the flow of drying air as the drying air is introduced into the drying chamber;
• a powder recovery system which collects the particles dried in the drying chamber and which removes the air from the spray dryer after it has passed through the drying chamber;
• the air distribution system including a first distribution chamber having a first air flow path defined therein between a first point and a second point;
• means for connecting the air supply means with the first chamber adjacent to the first point so that air may flow in the first chamber along the first defined air flow path from the first point to the second point;
• the air heating means being disposed in the first chamber in the first defined air flow path and between the first and second points;
• a diffuser member having a first and second end portions, with at least the first end portion being disposed in the first chamber adjacent to the second point of the first defined air flow path, the first end portion of the diffuser including a wall having a plurality of relatively small holes therein which permit heated air flowing along the first defined air path to flow through the small holes and into the interior of the diffuser member, with the plane of the wall being disposed at an angle with respect to the first defined air flow path;
• and means defining a second air flow path and extending between the interior of the diffuser member and the interior of the drying chamber, with the second defined air flow path being substantially perpendicular to the first defined air flow path.