Dosing equipment is the most mechanically abused asset on an alternative fuel line — rotary feeders, weigh belts, and metering screws run continuously against abrasive, inconsistent material that wears components far faster than the same equipment handling raw meal. Plants that treat dosing equipment with generic PM intervals borrowed from clean-service machinery consistently see premature feeder failure and dosing accuracy drift that throws off the entire fuel substitution ratio. Start free on OxMaint to run AFR-specific dosing PM schedules, or book a demo to see dosing accuracy tracking live.
Alternative Fuels · Preventive Maintenance
Alternative Fuel Dosing Equipment PM Checklist
Component-by-component preventive maintenance built for the abrasive, inconsistent material that standard PM intervals don't account for.
±2%Target Dosing Accuracy
3-5xFaster Wear vs. Clean Material Feeders
WeeklyRecommended Calibration Check
Why Standard PM Intervals Fail on Dosing Equipment
A weigh feeder calibrated for consistent, dry, free-flowing material behaves very differently when dosing shredded tyre chips, biomass fines, or RDF fluff. Particle size variation, moisture swings, and abrasive content all accelerate wear on load cells, screw flights, and seals at rates that generic OEM intervals were never designed around. The result is dosing accuracy that drifts silently until a fuel substitution audit catches the gap.
PM Checklist by Component
Rotary Feeder / Airlock
Rotor blade tip clearance measured against housing — replace blades once clearance exceeds manufacturer tolerance
Shaft seal inspected for material leakage or air ingress affecting downstream pressure
Drive motor amperage trended against baseline to catch developing mechanical resistance
Housing interior checked for material buildup reducing effective rotor pocket volume
Weigh Belt Feeder
Load cell calibration verified weekly using certified test weights
Belt tracking and tension checked — misalignment directly skews weight readings
Belt scraper and skirting inspected for wear allowing material spillage at edges
Speed sensor and encoder confirmed reading accurately against belt travel
Metering Screw Conveyor
Screw flight wear measured at outer edge — abrasive AFR materials erode flight diameter over time
Bearing temperature logged each shift, with trend comparison against baseline
Inlet hopper checked for bridging or rat-holing affecting consistent screw fill
Drive coupling and gearbox oil level and condition checked per OEM interval
Dosing Valve & Control System
Valve actuator stroke tested for full range of motion without sticking
Control loop response time verified against setpoint changes
Dosing accuracy cross-checked against manual sample weigh-off monthly
Alarm thresholds for under/over-dosing confirmed active and correctly set
Build Dosing-Specific PM Schedules in OxMaint
Set wear-based intervals per component instead of generic OEM defaults, with calibration checks scheduled automatically and accuracy trends tracked over time.
PM Frequency Reference
Signs Your Dosing Equipment Needs Off-Cycle Attention
Dosing Accuracy Drifting Beyond ±2%
When manual weigh-off checks consistently show drift beyond your target accuracy band, it almost always traces back to load cell calibration or worn screw flights rather than a control system fault.
Rising Motor Amperage Without Output Change
A creeping amperage trend at constant dosing rate signals developing mechanical resistance — typically bearing wear, material buildup, or seal drag — well before a hard failure occurs.
Inconsistent Material Flow at Hopper Inlet
Bridging or rat-holing at the inlet starves the metering device intermittently, producing dosing inconsistency that looks like an equipment fault but originates upstream in material handling.
Frequently Asked Questions
How often should AFR dosing equipment be calibrated?
Weigh feeders and dosing valves handling alternative fuels should be calibrated weekly given how much faster abrasive AFR material drifts calibration compared to clean meal feeders. Monthly manual weigh-off checks against the digital reading provide an independent accuracy verification beyond the automated calibration routine. Plants running high-substitution-rate fuel programs often move to twice-weekly checks during the first few months of a new fuel source. Track these checks against the asset record in
OxMaint so drift trends are visible over time.
Why does dosing accuracy matter for fuel substitution rate?
Cement plants target a specific thermal substitution rate from alternative fuels to manage clinker quality and kiln stability, and that target depends entirely on accurate dosing of the AFR stream relative to conventional fuel. A feeder drifting even a few percent off its setpoint can push the actual substitution rate outside the planned range without anyone noticing until a kiln chemistry or emissions report flags it. Regular accuracy verification is therefore a process control issue as much as a maintenance one.
What causes premature wear in AFR metering screws?
Abrasive content in shredded tyre, biomass, and RDF material erodes the outer edge of screw flights far faster than the smooth flow of conventional raw meal, gradually reducing the screw's effective conveying volume per rotation. This shows up first as a dosing accuracy issue rather than a visible mechanical fault, since the screw still rotates normally while delivering less material per turn. Measuring flight diameter on a fixed interval catches this wear pattern before it affects dosing consistency.
Can OxMaint track dosing equipment wear trends automatically?
Yes — OxMaint lets you log component-level readings like flight diameter, bearing temperature, and calibration results against each asset, building a trend history that flags gradual wear before it causes a dosing failure. Calibration and inspection schedules can be set per component rather than relying on a single generic PM interval for the whole feeder.
Book a demo to see wear trending configured for your specific dosing equipment.
Stop Losing Substitution Rate to Silent Dosing Drift
Component-level PM schedules, calibration tracking, and accuracy trends — all in one dashboard.
