I. General Provisions

1. These specifications apply to the operation and management of electronic belt scale (including batching system) 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. The batching system is key equipment for ensuring the nutrient content of fertilizer products, and its metering accuracy directly affects product quality.
3. The electronic belt scale mainly consists of a weighing belt, drive pulley, bend pulley, weighing idlers, weighing bridge, load cells, speed sensor, weighing indicator (integrator), tensioning device, cleaner, and frame. Its working principle is as follows: the load cell detects the material load on the belt, the speed sensor continuously measures the belt speed, and the two signals are sent simultaneously to the weighing indicator. After calculation, the instantaneous flow rate and cumulative weight are displayed, thereby achieving continuous, automatic quantitative feeding and batching.

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 the belt for abnormalities such as fuzzing, cracking, and joint damage. Belt thickness should be uniform, and bonded areas should be smooth. Remove debris and accumulated material from the belt and scale body area (especially near the weighing bridge, weighing idlers, and sensors). Before restarting equipment that has been out of service for a long time (over 30 days), test the motor insulation with a megohmmeter.
2. Belt tension inspection: Check whether the belt tension is appropriate. Belt tension should always remain constant. Too loose easily causes slipping; too tight aggravates wear. Adjust to an appropriate level before startup.
3. Idler and pulley inspection: Check whether all idlers rotate flexibly, have no adhered material, and are not damaged (such as bearing seizure or deformation). Weighing idlers must not be eccentric; otherwise, measurement values will fluctuate. Check whether the drive pulley and bend pulley surfaces are clean and check the wear condition of rubber lagging (if any).
4. Cleaner inspection: Check the contact between the belt cleaner and the belt. If severely worn, adjust or replace it in time. Cleaning the belt surface is important for maintaining accuracy.
5. Electrical inspection: Power connections should be firm and reliable, insulation should be good, and grounding should be correct. All enclosures and conduits must be grounded. Check whether sensor wiring is intact and whether there is short circuit or open circuit. Cable protective sleeves must be intact to prevent moisture from entering the wire cores.
6. Weighing system inspection: Check whether the appearance of the load cells and speed sensor is intact, and whether the connecting cables are damaged, pulled, or loose. The speed sensor measuring wheel should remain clean and free of adhered material, and should maintain rolling contact with the belt without slipping or separation. Check whether terminals are tight, free of looseness and corrosion.
7. No-load trial run: For newly installed or overhauled equipment, connect power and preheat for more than 15 minutes. Let the belt scale run without load for a period of time and check the belt forward/reverse rotation and whether the belt deviates. Feed material only after confirming smooth operation and no abnormal noise.

2.2 Material Preparation

1. Confirm that the material to be batched contains no hard foreign matter such as iron blocks, stones, or broken packaging, so as to avoid scratching the belt or damaging the equipment.
2. Check whether the silo discharge outlet is unobstructed and not blocked. Check whether the material particle size meets process requirements.
3. The belt load should be adjusted within the indicator range. The instantaneous load should not exceed 125% of the range. It is recommended that the belt scale load be about 50%–80% of the range; too high or too low a flow rate will affect metering accuracy.

III. During Production Operation

3.1 Startup Sequence

1. When several feeders operate in series, start from the discharge end and start in sequence.
2. First start the batching system control power. After the indicator warms up and stabilizes, start each electronic belt scale and raw material belt conveyor in sequence.
3. After the equipment runs normally, begin feeding. All positions must maintain close contact, strictly follow formula requirements, input proportions into the system, quantitatively and uniformly add the pre-metered materials into the hopper, and keep the hopper supplied with material. Never let the hopper run empty.

3.2 Operation Monitoring

1. Belt status monitoring:
   • Continuously observe whether the belt deviates, slips, or vibrates abnormally. When belt deviation occurs, use anti-deviation idlers to correct it, especially within the scale area. Anti-deviation idlers should be installed in the scale area to ensure normal belt operation in the weighing zone.
   • Check the belt for damage, delamination, or breakage. Stop immediately if any problem is found.
2. Weighing system monitoring:
   • Observe whether the weighing display readings are normal and whether there is abnormal fluctuation. Check field instrument indications and calibrate with central control.
   • Frequently use the indicator zero adjustment function. Zero calibration should be performed under no-load and clean belt conditions, generally once every 1–2 days.
   • Observe whether the material distribution on the belt is uniform, avoiding severe offset load.
3. Sound and vibration monitoring: Check whether all rotating parts operate normally and whether there is abnormal noise. Stop immediately if any abnormality occurs.
4. Material flow monitoring:
   • Observe whether the discharge outlet is blocked and whether feeding is uniform.
   • Check whether material adheres to the belt or pulleys and whether idlers accumulate material. Clean promptly.
   • Keep the hopper supplied with material. Never let the hopper run empty; otherwise, batching accuracy will be affected.
5. Safety discipline: During operation, it is strictly prohibited for anyone to pass through, step over, sit, lie on, or crawl under the belt. It is not allowed to use the belt to transport other items. It is not allowed to use sticks, shovels, etc. to remove debris from running belts or pulleys. Guards for transmission parts must always remain installed.

3.3 Shutdown Operation

1. Normal shutdown:
   • After receiving the shutdown instruction, stop feeding first (close the silo gate).
   • Let the belt continue running until all material on the belt is discharged, then empty the material in the automatic batching hopper.
   • Shut down the electronic belt scale and belt conveyor in sequence.
   • Cut off the main power of the control cabinet and hang a “Stopped / Do Not Operate” warning sign.
2. Emergency shutdown (abnormal shutdown): Press the emergency stop button or cut off power for 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 on-site handling (mandatory):
   • After shutdown, maintain the mechanical equipment, clean the automatic batching scale, and clean the environment. Especially clean dirty material lumps on the weighing bridge, weighing zone idlers, and speed sensor.
   • Check the wear condition of the belt, idlers, cleaner, etc., and prepare for maintenance or replacement if necessary.
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 belt deviation, batching accuracy, and cumulative total), 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: Remove dust, adhered material, and debris from the scale body frame, belt surface, weighing idlers and near sensors, and speed measuring wheel (must be done after shutdown and power disconnection). Generally, thoroughly clean once every 5–7 days. Use clean water, a broom, or a belt cleaner. After cleaning, let the belt run idle until completely dry.
2. Belt inspection: Check whether the belt deviates, is damaged (tearing, edge wear, joint cracking), or is excessively slack.
3. Idler inspection: Visually inspect whether idlers rotate flexibly, have no adhered material, and are not damaged.
4. Zero point inspection: Check whether the indicator zero point is normal under no-load; perform zero adjustment if necessary.
5. Component inspection: Check whether the discharge outlet is blocked and whether bolts are loose.
6. Inspection record: Record operating temperature, belt status, cumulative total, etc.

4.2 Regular Maintenance

1. Lubrication maintenance:
   • Lubrication maintenance cycle:
     • Regularly lubricate transmission parts.
     • The injected lubricating oil must be clean, and seals must be good.
     • (Note: For detailed lubrication guidance, see the equipment lubrication nameplate.)
2. Belt tension and deviation correction:
   • Regularly check and adjust belt tension to the specified range. It is important to keep belt tension constant. Gravity take-up or screw take-up tensioning devices are recommended.
   • Check and adjust self-aligning idlers, head and tail pulley positions, or the tensioning device to ensure the belt runs centered in the weighing area.
3. Idler and pulley maintenance:
   • Manually rotate idlers in and near the weighing area and check whether rotation is flexible and noise-free. Replace idlers that rotate poorly, are damaged, or have abnormal noise.
   • Check the rubber lagging wear of the drive pulley and bend pulley, and remove adhered material.
4. Cleaner maintenance: Check the wear condition of the cleaner and adjust the contact between the cleaner and the belt.
5. Electrical system: Regularly inspect power and cable lines to ensure electrical safety. Protect load cells and signal cables. Cable protective sleeves must be intact to prevent moisture from entering the wire cores. The main signal cable should preferably have no joints. If joints are necessary, the wire cores and shielding wires must be welded separately and tightly wrapped with waterproof tape. Check motor insulation performance every six months.
6. Weighing system maintenance:
   • Zero calibration: Perform zero calibration regularly under no-load, clean, normal operating speed conditions. The zero point should be checked once a day. Dust and material accumulation on the weighing bridge is one of the main causes of zero drift.
   • Span calibration: Use standard chain weights, hanging weights, or actual material of known precise weight for calibration. Analog calibration should be performed once a month, and actual material verification once every three months.
   • Professional personnel should check whether the load cell force is vertical and free of lateral force interference. Use professional equipment to test electrical performance and sensitivity when necessary.

4.3 Long-Term Shutdown Maintenance

When the equipment is out of service for more than 30 days, thoroughly clean the belt and frame, and apply anti-rust grease to exposed rotating parts. If installed outdoors, cover the motor with a rain cover. Before restarting, test the motor insulation with a megohmmeter, trial run according to the no-load trial run requirements, and re-perform zero calibration. Feed production only after confirming normal operation.

4.4 Fault Handling Principles

1. If belt deviation, slipping, abnormal noise, abnormal metering, 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 replacing idlers and cleaners, cut off power and hang a “Do Not Close Switch” warning sign.

V. Common Faults and Remedies