Port Grain Silo Level Measurement and Inventory Management

Port grain terminals receive and dispatch material at high rates through conveyors, elevators and multiple silo routes. Dust, uneven piles, grade changes and large quantities in transit complicate level and inventory. Radar provides a useful continuous surface measurement, but routing records, weighing and independent high-level protection remain essential. Define whether each value supports routing, available-capacity planning, reconciliation or commercial stock reporting, because these duties have different uncertainty requirements. Use a common cut-off time and account for belt loads, elevator contents, delayed route changes and settling. Otherwise a technically correct surface reading can still produce a misleading inventory variance. Record the stated uncertainty with every calculated stock figure and investigate changes before applying new correction factors.

Characterize grain and operations

Record grain types, moisture, bulk density, fines, temperature and angle of repose. Include seasonal grades, fumigation and cleaning conditions. A configuration established for dense wheat may not represent light or dusty products.

Document ship unloading, truck or rail receipts, transfer routes, reclaim rates and maximum throughput. Material in conveyors and elevators can be significant compared with the remaining headspace.

Map pile and routing geometry

Locate each inlet, distributor, spout and outlet. Filling creates peaks that move with routing; discharge produces valleys or rat holes. Select the radar point for its actual duty and state the uncertainty when one point cannot represent average inventory.

Use routing status and weigh scales to confirm which silo receives material. A valid level trend cannot correct a wrong diverter position or material identity error.

Protect the radar from dust and impact

Keep the antenna outside the falling stream and rebound zone. Plot the complete beam against roof structures and expected pile slopes. Verify antenna aperture, nozzle projection and signal margin during maximum-rate filling.

Dust and condensation can create deposits. Establish safe inspection under terminal dust-control procedures. Any purge must comply with classified-area and food-safety requirements.

Address combustible dust and food safety

Use the site's dust classification, temperature limits and exact equipment certificate. Verify cable entries, bonding, grounding and special conditions of use. An IP rating alone does not establish dust-explosion suitability.

Choose cleanable materials and prevent contamination between grain grades. Record instrument opening or cleaning where it affects fumigation, hygiene or traceability.

Separate level from mass inventory

Radar measures a local surface. Volume requires silo and pile geometry; mass also requires bulk density that varies with moisture, variety and compaction. Present an uncertainty appropriate to the method.

Reconcile opening stock, certified receipts, dispatch weights and transfers using synchronized timestamps. Keep material in transit and route changes separate before modifying density factors.

Design and test high-level protection

High-level shutdown must include sensor response, filtering, PLC action, conveyor and elevator stopping time and grain already moving. Independent protection may be required where overfill creates structural, dust or product-loss hazards.

Commission low, normal and high levels during filling and reclaim. Verify local display, PLC, inventory model, alarms, lost echo and route interlocks, then retain curves by grain type.

Engineering checklist

Record grain, moisture and density by grade.
Map moving inlet peaks and outlet valleys.
Keep radar outside impact and dust traps.
Verify dust certification and food safety.
Reconcile weights, routes and material in transit.
Test complete conveyor stopping response.

Frequently asked questions

Can radar replace terminal weighing?

No. Radar supports level and estimated inventory; commercial mass requires the appropriate weighing system.

Why can inventory change after filling stops?

Material still in conveyors enters the silo, and the pile may settle or bulk density may change.

Can one setting cover all grains?

Only if representative evidence shows adequate performance across their density, moisture and dust ranges.

Need a project-specific review? Send process data, drawings, photographs and acceptance criteria through our contact page.