Silo Reclaim Systems

Reclaim begins inside the stored material. As the feeder removes solids, stresses redistribute and a flow channel develops. The geometry and wall surface determine whether most material moves or a narrow channel empties while material remains stationary around it.

Process purpose

The design can aim for first in first out residence, consistent composition, controlled rate or maximum live capacity. These objectives may require mass flow, expanded flow or another engineered pattern rather than a generic cone and outlet.

Bulk solids behavior

Stored powder can form a cone, an inverted cone, an asymmetric surface or several peaks and valleys. The shape changes with filling location, withdrawal pattern, segregation and wall friction. A height at one point is therefore not automatically equal to average level, volume or mass.

Jenike based storage design links measured flow properties, hopper geometry and feeder drawdown. The flow pattern affects live capacity, residence time, segregation and the relationship between surface shape and inventory.

How the technology works

A screw, belt, rotary arm, vibrating device or other reclaimer activates part of the silo floor or hopper outlet. Uniform drawdown requires the device to increase extraction appropriately along an elongated opening instead of taking most material at one end.

Moisture, storage time, fine content and temperature can increase cohesive strength. A system that works with fresh dry material may fail after consolidation. Scale models and flow testing can reduce uncertainty for difficult duties.

Engineering inputs

• Cohesive strength and wall friction across conditions.
• Required flow pattern and live capacity.
• Outlet size and geometry.
• Feeder load, starting torque and extraction profile.
• Residence time and segregation limits.
• Access for inspection without entry.

Inventory, control and safety are different duties

A continuous inventory signal supports planning and process control. An independent high level switch may protect against overfill. A low level switch can protect downstream equipment or indicate loss of feed. The required reliability and proof testing can differ for each function.

Remote measurement can reduce the perceived need to inspect material manually, but it does not make silo entry safe. OSHA identifies engulfment, moving equipment and hazardous atmosphere controls for grain storage entry. Similar hazards require assessment wherever people could enter stored bulk solids.

Commissioning and validation

1. Confirm the vessel geometry and internal obstructions.
2. Map filling and withdrawal points.
3. Define whether the output is level, volume, mass or alarm state.
4. Set realistic uncertainty across expected surface shapes.
5. Compare readings with an independent reference over several cycles.
6. Test alarms, signal loss and implausible values.
7. Repeat validation after material or process change.

Maintenance and diagnostics

Monitor rate, motor load, vibration and remaining inventory. A growing difference between measured inventory and expected discharge can indicate stagnant material. Clearing should never rely on personnel walking on or entering moving bulk solids.

Trend review is useful because a sudden change in indicated surface, fill rate or reclaim rate can reveal buildup, a blocked outlet, a changed material or a sensor problem. Automated values should be checked against process knowledge rather than accepted without plausibility review.

Sources and further reading

• AIME, Selection and Sizing of Feeders, Bins and Stockpiles
• CIM, Principles of Flow of Bulk Solids
• Radar simulation for bulk material level measurement
• IEEE, Radar Sensors for Industrial Level Measurement
• OSHA, Grain Handling Facilities

Define the material, process objective, capacity, operating conditions, cleaning needs, safety duties and evidence required before comparing equipment.