I. General Provisions

1. These specifications apply to the operation and management of rotary drum screening 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 fertilizer rotary drum screen mainly consists of a motor, reducer, drum device, frame, sealing cover, and feed/discharge ports. Material classification and screening are achieved through the rotation and inclination of the drum.

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. 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 whether transmission parts (such as chains, gears, bearings, etc.) are well lubricated; add lubricating oil when necessary.
3. Screen body and surrounding inspection: Confirm that there are no obstacles around the screen body that would hinder operation, that the screen mesh is not damaged or blocked, and that the sealing cover is intact.
4. Electrical inspection: Power connections should be firm and reliable, insulation should be good, and grounding should be correct.

2.2 Material Preparation

1. Confirm that the material to be screened contains no hard foreign matter such as iron blocks or stones, so as to avoid breaking the wheel shaft or damaging the screen mesh.
2. Before startup, apply grease to the gears.

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. The rotary drum screen must be started first. After the equipment runs normally, start the feeding equipment.
3. Jog the motor control button to confirm that the motor rotation direction is consistent with the direction marked on the rotary drum screen.

3.2 Operation Monitoring

1. Feeding operation: After the screening machine runs smoothly, start the feeding and discharging equipment for feeding. After normal discharge, the sealing isolation cover should always remain closed.
2. Bearing temperature monitoring: During operation, frequently check the temperature of the main shaft bearing. The maximum temperature must not exceed 75°C, and the temperature rise must not exceed 45°C.
3. Operation status monitoring: Closely monitor the operating sound. If abnormal sound or severe vibration is found, stop immediately and inspect. Regularly check the discharge particle size to confirm that the classification effect meets process requirements.

3.3 Shutdown Sequence

1. Normal shutdown steps:
   • Stop feeding: First stop the feed conveyor (or upstream equipment such as an elevator) and cut off the incoming material.
   • Empty material: Let the rotary drum screen continue running for 3–5 minutes until the residual material in the drum is completely discharged and no material flows out of the discharge outlet. This step is crucial and can prevent material caking and screen mesh blockage.
   • Shut down the main machine: After confirming that the drum is empty, shut down the rotary drum screen motor.
   • Shut down auxiliary equipment: After the main machine has completely stopped, shut down the discharge conveyor belt, dust removal system, and other related auxiliary equipment in sequence.
   • 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): If any of the following conditions occurs, 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.
3. Post-shutdown on-site handling (mandatory):
   • Internal cleaning: Open the observation door or inspection door and clean residual material adhering to the screen mesh surface and inside the drum. If the material is corrosive or easily caked, use a copper shovel or special tool for cleaning. It is strictly prohibited to strike the screen mesh forcefully with an iron hammer, so as to avoid deformation and damage of the screen mesh.
   • Anti-rust treatment: After cleaning, apply an appropriate amount of waste engine oil or anti-rust oil to the riding ring, support roller surfaces, and exposed transmission chains of the rotary drum screen 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 observation doors and 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, 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 the material inside the screen and apply machine oil to the riding ring for rust prevention.
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, sealing gaskets, 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. Regularly add grease to sprockets and other parts.

4.3 Long-Term Shutdown Maintenance

When the equipment is out of service for more than 30 days, in addition to daily cleaning and anti-rust work, the motor insulation must be tested with a megohmmeter before restarting. Power-on trial run may be carried out only after confirming that the insulation is good. For equipment out of service for more than 6 months, the main shaft bearing must be removed and cleaned before installation, and new grease must be injected.

4.4 Fault Handling Principles

1. If abnormal sound, 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 replacing the screen mesh or repairing transmission parts, cut off power and hang a “Do Not Close Switch” warning sign.

4.5 Special Maintenance

1. Riding ring and support rollers: Newly installed riding rings are prone to loosening and must be checked frequently. Check the contact between support rollers and supporting riding rings. If support rollers in the same group are not parallel or the line connecting two support rollers is not perpendicular to the drum axis, it will cause excessive force on the thrust rollers and abnormal wear of the support rollers.
2. Transmission gears: If the pinion and girth gear make abnormal noise during operation, check the gear meshing clearance. If the pinion is severely worn, replace it in time. The gear guard should be well sealed to prevent dust entry.
3. Bearings: If bearing oil temperature rises, stop immediately to inspect the cause and eliminate it. Dust and other debris should be removed from the base frame plane of the movable device.
4. Screen mesh: After stopping the machine and cutting off power, open the inspection door and enter the drum interior (confined space operation approval must be implemented), and check the tension and wear of the screen mesh section by section. If the screen mesh is partially damaged, it can be repaired by riveting a patch (mesh size must be identical). The patch overlap length is required to be ≥50 mm, and the overlap should be downstream along the material flow direction to prevent material from scraping and flipping the patch. If the damaged area exceeds 30% of the entire screen mesh, the entire screen mesh should be replaced. After replacing with a new screen mesh, it must be trial-run under no-load conditions for 30 minutes to confirm that the screen mesh has no looseness, abnormal noise, or scraping against the casing.
5. Motor and reducer: For maintenance, see the motor and reducer operation and maintenance manuals.

V. Common Faults and Remedies