I. General Provisions

1. These specifications apply to the operation and management of rotary drum coating (rotary coating) equipment in fertilizer production workshops, covering the entire process of pre-production preparation, production operation, and maintenance.
2. Operators must pass training before taking up their posts. Before operation, they shall become familiar with the equipment structure and the contents of these specifications.
3. The rotary drum coating machine mainly consists of a drum, motor, reducer, support roller device, thrust roller device, transmission gears (pinion and girth gear), powder dusting or liquid spraying system, feeding device, discharging device, and sealing cover. The rotation of the drum causes the material to tumble; combined with powder dusting or liquid spraying, the coating agent is evenly wrapped around the particle surfaces, effectively preventing fertilizer caking and achieving a slow-release effect.

II. Pre-Production Preparation Stage

2.1 Pre-Startup Inspection

1. Equipment integrity inspection: Check whether all parts are installed securely and whether fasteners are loose. Check whether there are foreign objects or accumulated material in the drum; clean them promptly if present. Before restarting equipment that has been out of service for a long time (over 30 days), test the motor insulation with a megohmmeter to prevent motor burnout.
2. Lubrication system inspection: Check the lubrication condition of each bearing housing and the reducer. For first use, the reducer must be filled with gear oil (No. HJ40-50 mechanical oil or No. HL20-30 gear oil; oil level within the range indicated by the circular oil sight gauge) before production. Check whether the oil quantity at each lubrication point (gears, girth gear, riding ring, support rollers) is sufficient. Dry grease should be applied to gears and riding rings.
3. Drum and surrounding inspection: Confirm that there are no obstacles around the drum that would hinder operation, and that the sealing cover is intact. The drum is generally installed at an inclination of 2–5 degrees (adjustable as required). Check whether the riding ring and support rollers are in good contact.
4. Electrical inspection: Power connections should be firm and reliable, insulation should be good, and grounding should be correct. Do not start the coating machine without proper grounding. If current is detected on the equipment, stop immediately until the grounding wire is repaired.
5. Coating system inspection: Check whether nozzles are clogged and whether spray pipelines are unobstructed. For powder coating, check whether the powder dusting machine operates normally.
6. No-load trial run: For newly installed or overhauled equipment, after startup first check whether the rotation direction is correct (the pinion and girth gear should rotate in opposite directions; if the direction is wrong, swap any two motor terminals to change the rotation direction). Feed material only after confirming smooth operation and no abnormal noise. Newly installed equipment should undergo a no-load trial run to ensure that bearing temperatures rise steadily and gear noise is uniform.

2.2 Material Preparation

1. Confirm that the material to be coated (granular fertilizer) contains no hard foreign matter such as iron blocks or stones, so as to avoid damaging the drum or lifting structure.
2. Before the material enters the coating machine, ensure that the particle temperature is suitable (usually after cooling before entering the coating process) to ensure the coating effect.

III. During Production Operation

3.1 Startup Sequence

1. This machine must be started under no-load conditions. Startup with material is strictly prohibited.
2. After confirming that the rotation direction is correct, start the main motor of the coating machine.
3. After the equipment runs smoothly, start the upstream feeding equipment and the coating agent spraying (or powder dusting) system.

3.2 Operation Monitoring

1. Feeding operation: After the coating machine runs smoothly, start the feeding equipment for uniform feeding, and at the same time turn on the coating agent spraying or powder dusting device. After normal discharge, the sealing cover should always remain closed.
2. Bearing temperature monitoring: During operation, frequently check the temperature rise of each bearing. For long-term use, the bearing temperature must not exceed 50°C.
3. Operation status monitoring:
   • Closely monitor the operating sound. Gear noise should be uniform and should not fluctuate. If abnormal sound or severe vibration is found, stop immediately and inspect.
   • Check the drum for axial movement and vibration. The riding ring should not show obvious vibration.
   • If uneven coating or exposed substrate is found, immediately check whether the spray volume is sufficient and whether the nozzles are clogged; appropriately adjust the drum speed to ensure uniform particle tumbling.
   • If the coating layer easily falls off or powders, reduce the feed rate and extend the residence time, or appropriately increase the coating agent spray volume.
4. Discharge effect monitoring: Regularly check the discharge coating effect (coating uniformity and coating firmness) to confirm that the coating quality meets process requirements.

3.3 Shutdown Operation

1. Normal shutdown:
   • Stop feeding: First stop the upstream feed conveyor, stop adding raw material into the coating machine, and close the coating agent spraying system.
   • Empty material: Let the coating machine continue running until the material in the drum is completely discharged and no material flows out of the discharge outlet. This step is crucial. If the machine is stopped before the material is fully discharged, residual material will adhere to the drum inner wall and lifting structure; after hardening, the next startup will be difficult.
   • Shut down the main machine: After confirming that the drum is empty, shut down the main motor of the coating machine.
   • Power isolation and tagging: Disconnect the main power of the equipment control cabinet and hang a “Stopped / Do Not Operate” warning sign.
2. Emergency shutdown (abnormal shutdown):
   • Immediately press the emergency stop button or cut off power to perform emergency shutdown.
   • Handling after emergency shutdown: The cause of the fault must be identified and eliminated before restarting according to the “Startup Sequence.” It is strictly prohibited to force startup before the fault is eliminated. At the same time, the emergency shutdown time, cause, and handling process should be recorded in detail in the Equipment Operation Record.
3. Post-shutdown site handling (mandatory):
   • Internal inspection and cleaning: Open the inspection door and check whether material adheres to the drum inner wall and lifting structure surface. Clean promptly if any. Clean the nozzles to prevent the coating agent from solidifying and clogging.
   • Anti-rust treatment: After cleaning, apply an appropriate amount of waste engine oil or anti-rust oil to the girth gear surface, riding ring surface, support roller surface, and exposed gears to prevent rust in open-air or humid environments.
   • Close sealing doors: After confirming that no tools or debris are left inside, close and lock all inspection doors to prevent dust entry or rain ingress (outdoor models).
4. Shift-change shutdown requirements:
   • Before handover, the equipment must be stopped and cleaned, and the Equipment Operation Record and Shift Handover Record must be truthfully filled in, noting the equipment operation status during the shift (key parameters such as bearing temperature, coating effect, and current), abnormalities, and countermeasures.
   • Before startup, incoming shift personnel must re-confirm the equipment status against the inspection requirements in the “Pre-Production Preparation Stage.”

IV. Maintenance and Care

4.1 Daily Maintenance (Each Shift)

1. Cleaning: After each shift, clean residual material inside and outside the equipment to prevent caking and corrosion of the equipment and next blockage. Clean residual material inside the drum and check the wear degree of the lifting plates.
2. Inspection: Check whether all parts operate normally. Pay attention to checking the wear degree of wearing parts.
3. Lubrication: Check whether transmission parts (such as chains, gears, bearings, etc.) are well lubricated; add lubricating oil when necessary.

4.2 Regular Maintenance

1. Lubrication maintenance cycle:
   • Regularly lubricate support rollers, thrust rollers, and transmission gears.
   • The injected lubricating oil must be clean, and seals must be good.
   • (Note: For detailed lubrication guidance, see the equipment lubrication nameplate.)
2. Wearing parts inspection and replacement: Regularly inspect support rollers, seals, bearings, V-belts, nozzles, and other wearing parts, and replace them in time. Severely worn V-belt transmission parts should be replaced in time.
3. Electrical system: Check motor insulation performance every six months; inspect circuits to eliminate leakage and short-circuit hazards.
4. Rotating parts inspection: Regularly check rotating parts for flexibility and whether there is jamming; check gear and girth gear meshing and tooth surface contact status (the meshing surface should have no pitting, scars, marks, etc.); check the contact between the riding ring and support rollers.

4.3 Long-Term Shutdown Maintenance

When the equipment is out of service for more than 30 days, the material in the drum must be completely discharged and cleaned, and anti-rust grease should be applied to exposed parts such as gears, girth gear, riding rings, and support rollers. During long shutdown, remove the transmission belts to prevent belt damage. Before restarting, perform a motor insulation test with a megohmmeter, trial run according to the no-load trial run requirements, and only feed production after confirming normal operation.

4.4 Fault Handling Principles

1. If abnormal noise, excessive bearing temperature, severe vibration, etc. are found, stop immediately; restart only after the cause is identified and the fault is eliminated.
2. It is strictly prohibited to run equipment with faults, and strictly prohibited to perform maintenance or cleaning while the equipment is running.
3. When repairing transmission parts or entering the drum interior, cut off power and hang a “Do Not Close Switch” warning sign. Entering the drum interior also requires the confined space operation procedure of “ventilate first, test second, work last.”

V. Common Faults and Remedies