Pre-Operation Comprehensive Preparation
Equipment Check: Before starting the equipment, carefully inspect key components such as the refrigeration system, vacuum system, and heating system. Check the refrigeration compressor lubricating oil level within normal range, inspect vacuum piping for damage and connection tightness, and confirm heating plate surfaces are free of foreign objects with temperature sensors working properly.
Material Preparation: Pre-process materials according to material characteristics and freeze-drying process requirements. For liquid materials, adjust appropriate concentration and filling volumes. For solid materials, ensure uniform particle size. Dispense materials into freeze-drying trays, ensuring uniform distribution to avoid excessive thickness affecting freeze-drying efficiency.
Parameter Setting: Based on the material freeze-drying process curve, accurately set pre-freezing temperature and time, heating plate temperature during sublimation drying, vacuum level, desorption drying temperature and time, and other parameters. For first-time freeze-dried materials, reference the process parameters of similar materials and optimize through small-scale experiments.
Critical Steps During Operation
Pre-Freezing Stage: Place trays loaded with materials into the drying chamber, close the door, and start the refrigeration system. Cool materials to the pre-freezing temperature at the set cooling rate and maintain for a sufficient time to ensure complete freezing of moisture in the materials. Monitor material temperature changes in real time through temperature sensors to ensure pre-freezing effectiveness.
Sublimation Drying Stage: After pre-freezing is complete, start the vacuum system to achieve the specified vacuum level in the drying chamber. Simultaneously start the heating system, slowly increasing the heating plate temperature at the set heating rate to provide heat for ice sublimation. Closely monitor vacuum level and material temperature changes during this stage to avoid abnormal phenomena such as product ejection or collapse. If vacuum level suddenly increases, the heating temperature may be too high causing localized overheating. If material temperature rises slowly, heating power may be insufficient or vacuum level inadequate.
Desorption Drying Stage: After sublimation drying is complete, appropriately increase heating plate temperature to further remove residual moisture from materials. Continuously monitor material moisture content during desorption drying. When the specified moisture content standard is reached, stop heating, close the vacuum system, slowly fill the drying chamber with sterile air or inert gas to atmospheric pressure, then remove the freeze-dried product.
Daily Maintenance
Cleaning: After each freeze-drying cycle, promptly clean the drying chamber, freeze-drying trays, and water trap components. Use a soft cloth and neutral cleaner to wipe the drying chamber inner walls and heating plate surfaces, removing residual materials and dirt. Clean frost from the water trap to prevent excessive frost buildup affecting water capture efficiency.
Seal Inspection: Regularly inspect the sealing performance of the drying chamber door, vacuum pipeline interfaces, and other parts. Ensure good sealing by applying vacuum sealing grease or replacing sealing rings to prevent outside air from entering and affecting vacuum level.
Lubrication: For equipment transmission components such as vacuum pump bearings and refrigeration compressor moving parts, regularly add lubricating oil or grease according to equipment manual requirements to ensure normal component operation and reduce wear.
Periodic Maintenance
Performance Testing: Quarterly, conduct comprehensive testing of the freeze dryer's refrigeration, vacuum, and heating performance. Use testing instruments to measure the accuracy and stability of refrigeration temperature, vacuum level, and heating plate temperature to ensure equipment performance meets requirements.
Filter Replacement: Replace air filters and vacuum pump oil mist filters in a timely manner. Air filters prevent external dust and impurities from entering the equipment and affecting freeze-dried product quality. Generally, air filters should be replaced every 6 to 12 months, and vacuum pump oil mist filters should be replaced every 3 to 6 months based on usage frequency.
System Calibration: Annually calibrate temperature sensors, vacuum sensors, and other key sensors to ensure measurement data accuracy. Conduct comprehensive performance evaluation and adjustment of the refrigeration, vacuum, and heating systems to ensure long-term stable equipment operation.
