Patent ID: 9561988
Date: 2017-02-07
CPC Classifications: B05B,C05G,Y02P

Claim:
1. A method for preparing controlled release fertilizer in a large closed numerically controlled fluidized bed coating machine, comprising the following steps, (1) sieving and collecting a granular fertilizer with a predetermined granule size range into a barrel; (2) sucking said granular fertilizer into a coating cavity via an automatic feeding system with a feeding port in said coating machine; (3) closing said feeding port so that an open system is changed to a closed system, and turning on an ID fan to make said granular fertilizer into a spouting fluidized state in said coating cavity; (4) setting coating parameters including air inlet temperature, air outlet temperature, nebulizing pressure, fluidizing pressure and coating time; (5) after said coating cavity's temperature reaches a preset air inlet temperature, feeding the coating liquid, which is under constant agitating, via a peristaltic pump into spray guns at the bottom of a main tower of said fluidized bed coating machine; (6) Turning on a circulating condensate water of the spray gun, so that said coating liquid, after being nebulized by compressed air, is spray coated on the surface of said granular fertilizer; (7) flowing the air from said coating cavity first into a cyclone separator to remove impurities; (8) flowing the air from said cyclone separator into a drying tower for dehumidifying so as to result in dehumidified air, which then flows, via said ID fan, into said coating cavity again so as to carry away more moisture from the coating liquid and form a closed circulating drying system to realize the cyclic utilization of hot air and reduce thermal energy consumption; (9) turning off said machine upon coating completion; and (10) opening a discharge port to collect coated controlled release fertilizer.