Detailed Guide on Maintenance and Calibration of Bulk Material Conveying Equipment Belt Scales
Time:2025-04-25 17:47:14Number of Clicks:
In modern bulk material conveying systems, belt scales serve as the core dynamic weighing equipment, widely used in coal, mining, power, ports, and chemical industries. They are critical tools for achieving precise material measurement, cost control, and trade settlement. With the advancement of industrial automation, their collaboration with belt conveyors, mobile shiploaders, truck unloaders, and other equipment has become increasingly important:
Belt Conveyors: The primary carrier of belt scales, responsible for long-distance, high-capacity material transport.
Mobile Shiploaders: Key equipment for bulk cargo loading in ports, relying on belt scales for real-time flow monitoring to prevent overloading or underloading.
Truck Unloaders: In mining and logistics scenarios, belt scales provide accurate discharge measurement, enhancing efficiency and cost management.
Daily Maintenance of Belt Scales
Harsh conditions such as high dust, humidity, and vibration can lead to zero drift, sensor failure, and calibration errors, resulting in measurement deviations that directly impact production efficiency and economic benefits.
Environmental Protection and Equipment Management
Conveyor System Protection
Indoor/Outdoor Installation Differences:
Install wind and rain shelters covering ≥12m before and after the weighing area, with a height ≥1.7m.
Regularly inspect anti-rust coatings to prevent corrosion-induced accuracy loss.
Indoor Installation: Prefer enclosed environments to minimize external interference.
Outdoor Operation (e.g., Port Mobile Shiploaders):
Scale Frame Maintenance Key Points
Cleaning Standards:
Remove accumulated material after shutdown using compressed air to clean levers and roller gaps.
For sticky materials (e.g., wet coal, mineral powder), increase cleaning frequency to once daily.
Roller Maintenance:
Lubrication Cycle: Apply high-temperature lithium grease every 6 months, then run idle for 10 minutes before zeroing.
Replacement Criteria: Replace rollers with radial runout >0.5mm or axial movement >1mm immediately.
17A/B Belt Scale Balancing Adjustment
Imbalance Warning Signs
Flow fluctuation >5% on the display.
Continuous accumulation during no-load operation.
Voltage difference between two sensors >1mV.
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Power off → Disconnect sensor signal cables → Power on to measure voltage → Adjust suspension nuts → Re-measure voltage → Tighten nuts → Re-zero. Note: At least two material calibrations are required post-adjustment.
Instrument Maintenance and Lightning Protection
Anti-Interference Design
Use shielded twisted-pair signal cables with grounding resistance <4Ω.
Install away from strong interference sources like inverters and large motors.
Lightning Protection Measures
Three-Level Protection: SPD modules (power), isolators (signal), and lightning terminals (sensors).
Rainy Season Inspection: Weekly grounding checks and post-rain sensor insulation tests.
Precision Calibration Procedures
Zero Calibration for Industrial Scenarios
Multi-Equipment Calibration Challenges
Mobile Shiploaders:
Shorten zeroing cycles to once per shift due to wind and vessel movement.
Apply "dynamic zeroing + wave compensation algorithms" to reduce errors.
Truck Unloaders:
Run idle for 3 cycles post-discharge before zeroing to mitigate material impact.
Install buffer roller sets to minimize belt vibration.
Zero Tracking Configuration
Trade Settlement: Set tracking range to 0.5%~1% to avoid false triggers.
High-Humidity Environments (e.g., Coastal Ports): Disable auto-tracking; use manual zeroing.
Calibration Method Selection & Error Control
Method
Application Scenario
Accuracy
Time
Cost
Material
Trade settlement, annual checks
0.2%~0.5%
4~8h
High
Chain Code
Monthly checks, acceptance
0.5%~1%
2~3h
Medium
Hanging Code
Quick inspections, troubleshooting
1%~2%
0.5h
Low
Chain Code Calibration Example (Port Mobile Shiploader):
Use 20kg/m high-precision chain code, covering ≥8 idler sets.
Secure chain code along the belt centerline, run at rated speed (typically 2.5m/s).
After 3 cycles, input theoretical value:Testtonnage=(20×L×3)/1000, where L is belt circumference (laser-verified).
Calibration Data Management & Smart Upgrades
Data Traceability System
Maintain calibration logs with timestamps, operator, and environmental data (temperature, humidity).
Integrate 2105 weighing instruments with MES via RS485 for automated data uploads.
AI-Assisted Diagnostics
Train models on historical data to predict sensor aging or belt slippage.
Case Study: A power plant extended calibration intervals from 7 to 30 days using AI on truck unloaders, cutting annual costs by 42%.
Industry Innovations & Upgrade Trends
Next-Gen Belt Scale Technologies
Idler-Free Weighing: Measures belt tension directly, achieving 0.1% accuracy in mobile shiploaders.
5G + Edge Computing: Real-time cloud data transmission for multi-truck unloader coordination.
Key Equipment Selection Guide
Belt Conveyors: Prioritize frames with stiffness >150N/mm² to reduce deformation errors.
Mobile Shiploaders: Equip hydraulic auto-aligning systems (belt deviation <10mm).
Truck Unloaders: Adopt variable-frequency drives + soft-start to minimize material impact.
From 10,000-ton mobile shiploaders in ports to cost control in mining truck unloaders, belt scales remain the "gatekeepers of quality" in bulk material systems. Through scientific maintenance, scenario-based calibration, and smart upgrades, enterprises can significantly reduce costs and enhance competitiveness. As Industry 4.0 technologies mature, belt scales will unlock greater data value, empowering global logistics and energy sectors toward high-quality development.
