Operation Procedures of Low-Speed Agitating Dryer

 英文详细介绍一下低速搅拌干燥机的操作方法，低速干燥机

# Operation Procedures of Low-Speed Agitating Dryer ## 1. Pre-Operation Inspection Before Startup 1.1 Mechanical inspection - Check the stirring motor, reducer and transmission components for abnormal noise, oil leakage or loose bolts; confirm the gear oil level of the reducer is within the standard range. - Inspect the inner tank, stirring paddles and cone-bottom scrapers to ensure no residual PET flakes, foreign hard objects or material caking inside the tank. - Verify all doors, inspection hatches and air ducts are tightly sealed without air leakage. 1.2 Air circulation & dehumidification system inspection - Check the molecular sieve dehumidifier, heating tubes, cyclone dust collector and HEPA filter for blockage or damage. - Confirm the hot air pipeline connection is intact, and the waste heat recovery channel is unobstructed. 1.3 Electrical & control system inspection - Switch on the main power supply, activate the PLC touch screen, and check if all sensors (temperature, dew point, material level, torque) display normal real-time data without alarm codes. - Test alarm functions including over-temperature, low material level, motor overload and high dew point to guarantee interlock protection works normally. 1.4 Auxiliary equipment check - Inspect the vacuum loader connected to the dryer for smooth feeding, and clean the filter bag of the feeding cyclone to remove accumulated dust. ## 2. Parameter Setting on PLC Touch Screen 2.1 Select material process curve - Choose the corresponding preset program according to raw material types: recycled rPET flakes, semi-dull PET chips or mixed PET materials. - If processing special materials, manually input customized parameters as below: - Stirring speed: 5–20 RPM (8–15 RPM for rPET flakes) - Crystallization zone temperature: 140–150℃ - Constant drying temperature: 160–175℃ - Target hot air dew point: ≤ -50℃ - Total material residence time: 120–240 min - High & low material level alarm limits 2.2 Set safety protection values - Set over-temperature protection threshold (max 180℃), overload torque limit for stirring motor, automatic stop parameter for material shortage. ## 3. Machine Startup Sequence 3.1 Start the dehumidifying hot air system first - Tap the “Air System Start” button; the molecular sieve dehumidifier and circulating fan run first. - Wait 5–10 minutes until the hot air dew point drops below -50℃ before activating heating. 3.2 Activate heating system - Turn on electric heating or thermal oil heating; the system heats the tank following the preheating-crystallization-drying segmented temperature curve automatically. 3.3 Start the stirring system - After the tank preheats to 120℃, press the “Stirrer Start” button. The agitator runs at set low speed to avoid local overheating and material adhesion. 3.4 Launch automatic feeding - When the temperature reaches the crystallization preset value, start the vacuum loader for automatic feeding. - Stop feeding once the material fills 60%–75% of the tank effective volume, controlled by high-level sensor signal. ## 4. Normal Running Monitoring During Production 4.1 Real-time data observation - Regularly check touch screen data: tank temperature, hot air dew point, stirring rotation speed, motor torque, material residence countdown and material level height. - Maintain stable dew point below -50℃ at all times; if dew point rises abnormally, clean or replace the molecular sieve filter in time. 4.2 Material status inspection - Open the small observation window periodically to check material condition: PET flakes should be loose, dry and non-sticky without agglomeration. - If bridging or caking appears, slightly increase stirring speed and lower heating temperature temporarily. 4.3 Troubleshoot real-time alarms - Over-temperature alarm: Cut off heating, check heating tube damage and air circulation blockage. - Motor overload alarm: Stop feeding, run the stirrer continuously to break material lumps, clean accumulated dead-corner flakes. - High dew point alarm: Check filter clogging or molecular sieve aging. 4.4 Continuous discharging coordination - The bottom discharge paddle discharges dried PET synchronously with feeding to maintain stable material volume inside the tank. Match discharging speed with the follow-up extruder or pelletizer to avoid material backlog. ## 5. Normal Shutdown Procedure 5.1 Short-term temporary stop (production pause within 2 hours) - Stop feeding first; keep stirrer and hot air system running to prevent residual materials from melting and sticking. - Lower the heating temperature to 130℃ for heat preservation standby. 5.2 Full production line shutdown (end of daily work) 1. Stop vacuum feeding, run the machine continuously to discharge all materials inside the tank completely. 2. Cut off heating power, keep the fan and stirrer running to cool down the tank naturally below 80℃. 3. Stop the stirring motor and circulating fan after cooling finished. 4. Turn off the main power supply of the whole equipment. ## 6. Post-Shutdown Cleaning & Maintenance 6.1 Tank cleaning - Open the access door after full cooling; use compressed air and soft brushes to clean residual PET powder and fine flakes on the tank wall and paddles. - For food-grade material switching, wipe the tank with food-safe alcohol and dry thoroughly. 6.2 Filter & dust collector maintenance - Dismantle cyclone dust collector and HEPA filter, remove accumulated dust and replace damaged filter elements regularly. 6.3 Lubrication inspection - Check reducer oil level and stirring bearing grease; replenish or replace lubricating oil according to maintenance cycle.