The phenomenon of sticking wall is a prominent problem that hinders the normal operation of the spray dryer, especially the spray drying process of solid preparations (especially traditional Chinese medicine)The material stick wall is not only not conducive to operation collection, but also over time, sensitive adhesive wall material will deteriorate into non-conforming materialFrom the process point of view, the solution includes the selection of suitable solvents, the addition of accessories, change of process parameters, but these methods can not adjust the room is not very large, so we must seek a fundamental solution from the point of view of equipmentThe researchers studied the problems of sticky walls and clumps in the drying process, and concluded that the main cause of the sticky walls was wall temperature.
Spray dryer sticky wall generally has the following three conditions: 1, semi-wet material sticky wall: the reason is that the sprayofe drops before not reaching the surface drying has been in contact with the machine wall, and therefore adhereto to the wall, the position of the sticky wall is generally sprayed against the nebulizer fog droplets movement The plane of the trajectory, and the structure of the nebulizer, the hot air in the tower's motion state is related; 2, the hot melting stick wall of the low melting point material: the reason is that the material reaches the melting point at a certain temperature to dissolve and stick, adhere to the wall of the device; 3, Dry powder surface adhesion: dry powder in the limited space movement there will always be some toucher wall, which is inevitable, but such a sticky wall is generally not thick, as long as the air blow or gently knock can shock down, zui simple solution is the inner wall polishing, can solve this problem to some extent. The following common methods to prevent sticky walls are: 1, the use of clamp-wall drying tower, during which air cooling, so that the wall temperature is kept below 50 degrees C; Install a row of nozzles composed of air brooms, and make it slowly rotate along the tower wall; 4, the tower wall to increase the air hammer, through the air hammer, force disengage the adhesive wall material; 5, increase the processing accuracy of equipment, the inner wall of the tower polishing can also reduce the sticky wall.
