Precautions for the use of spray fluidized bed granulator should be combined with equipment characteristics and process requirements, focusing on operation specifications, safety protection and exception handling:
1、 Preparation before operation
1. Material pretreatment: When there is a significant difference in the specific gravity or particle size between the main drug and auxiliary materials, they need to be mixed in advance to avoid fluidized stratification that affects particle uniformity. The loading capacity needs to be adjusted according to the bulk density of the material. If it is too much, the bed may collapse, while if it is too little, effective annular fluidization cannot be formed.
2. Equipment inspection: confirm that the spray system is not blocked and the atomization status of the nozzle is normal; The holes in the fluidized bed distribution plate need to be cleaned to prevent uneven airflow. Electrical system parameters (such as temperature sensors, pressure instruments) should be calibrated to the required process range.
2、 Operation control
1. Parameter adjustment: the spray speed needs to be comprehensively controlled by the rotational speed of the peristaltic pump, the caliber of the spray gun, etc. If it is too fast, it is easy to cause particles to agglomerate, and if it is too slow, fine powder will increase. The inlet air temperature needs to be adjusted according to the characteristics of the material (such as low-temperature operation for thermosensitive materials).
2. Fluidization status monitoring: In case of channeling, agglomeration or bed collapse, spray shall be stopped immediately and the fluidization status shall be restored through the blowing function.
3、 Safety and Maintenance
1. Treatment of corrosive materials: materials containing acid and alkali components shall be immediately flushed inside the spray system and fluidized bed after use to prevent corrosion.
2. Shutdown protection: Long term shutdown requires emptying the liquid supply pipeline, spraying anti rust oil, and cutting off the power supply. Before maintenance, residual pressure on the equipment must be released, and high-temperature components must be cooled to room temperature when disassembled.
4、 Special working conditions
1. Organic solvent operation: If flammable solvents are involved, it is necessary to verify the explosion-proof system interlock (such as oxygen content ≤ 8% VOL) and maintain a slight negative pressure state.
2. Laboratory equipment: For small fluidized beds, attention should be paid to the sample size (such as 50 grams for experiments), and parameters should be dynamically monitored using a touch screen.
The above measures can ensure stable operation of the equipment and improve the quality of granulation.