Bolted Silo
Application Tips
Utilizing prefabricated silos for steel construction means that projects can be completed quickly; construction time can be reduced by 70% through the use of factory-standardized designs and bolt-on assembly.
Prefabricated steel construction means that the construction of silos is a cost-effective solution for grain and bulk storage. A steel silo is a lighter construction option for bulk storage than reinforced concrete. This means a reduced substructure and smaller foundation.
Flexibility and adaptability are the hallmarks of bolted steel construction. Modular silos can be fully disassembled, relocated, and easily expanded in capacity.
Spiral Silo Design Guidelines for 8 Major Industries
Considerations for silo design specifications and performance criteria for the cement, power, grain, feed, chemicals, food processing, construction, and mining industries. Spiral silos are silo designs which are aimed at flexible bulk storage of the various industries and incorporate the necessary range of sealing and structural performance.
- Fluidized Homogenization Discharge Angle
Short cone slope ≥ 55° with fluidization systems ensuring ≥ 85% discharge homogenization. - High-Abrasiveness Part Liner Thickness
Impact zones and hoppers lined with ≥ 8mm Mn13 steel or ≥ 20mm wear-resistant ceramics. - Eccentric Discharge & Settlement Control
Structures rated for 5,000–20,000 t loads; differential foundation settlement capped at 0.002L.
- Drop Velocity & Degradation Control
Multi-stage spiral chutes limiting material velocity to ≤ 1.5 m/s and crushing rate to ≤ 0.5%. - High-Temperature Thermal Stress & Special Sealing
FKM seals rated for 250°C to handle 80–130°C feed, with a 2mm/m expansion gap. - Low-Oxygen Anti-Combustion & Moisture Control
N2 blanket maintaining 200–500 Pa micro-positive pressure and ≤ 8% O2 volume concentration.
- Explosion Relief Venting Area Ratio
Roof explosion vents configured to a venting area-to-volume ratio (A/V) of ≥ 0.03 m¹. - High-Grade Anti-Corrosion Selection
Double-sided HDG sheets (≥ 450 g/m²) for walls; 316L stainless steel for severe corrosion zones. - Rotary Paddle Level Indicator Pressure Rating
Instrument process interfaces rated at ≥ 1.0 MPa with Ex d IIC T4 Gb explosion-proofing.
- Temperature Monitoring Spacing & Density
Cables spaced horizontally at ≤ 5m; sensors (accuracy ±0.5°C) spaced vertically every 1.5–2m. - Gas-Tightness & Fumigation Pressure Half-Life
Two-component polysulfide sealing; pressure decay half-life from 500 to 250 Pa must be ≥ 60s. - Ventilation Duct Cross-Sectional Velocity
Main duct air velocity at 8–12 m/s; branch duct outlet velocity restricted to ≤ 4 m/s.
- Zero-Iron Impurity Contamination Control
Full-surface ≥ 0.3mm WC or PTFE coating, limiting magnetic iron pickup to ≤ 10 ppb. - Ultra-Fine Powder Efficient Dust Collection & Micro-Positive Pressure
PTFE-membrane filters ensuring ≥ 99.97% efficiency for 10–20 μm graphite dust (>1 μm). - High-Fluidity Material Leak-Proof Design
Bolt holes fitted with ≥ 2mm microcellular EPDM gaskets to eliminate micron-grade powder leakage.
- Super-Large Load Cross-Section Optimization
Lower wall plates thickened to 6–8mm to withstand high material densities (1.8–2.8 t/m³). - Extreme Mechanical Impact Protection
Dead-bed boxes installed at inlets to restrict the effective free-fall drop of heavy bulk items to ≤ 2m. - Resistant Ore Discharge Hopper Angle
Discharge cone angle set at 60–65° with ≥ 50mm rock wool insulation to prevent thermal warping.
- High Dynamic Load & Seismic Design
Seismic design rated for ≥ 7 degrees; material dynamic load coefficient Cd fixed at 1.2–1.3. - High-Moisture Material Anti-Sticking
Hoppers lined with 12mm UHMW-PE sheets to prevent bridging of concentrates with 8%–12% moisture. - Severe Outdoor Anti-Corrosion Environment Adaptation
≥ Class 10.9 high-strength fasteners with Dacromet coating surviving a >1,000h salt spray test.
- Hazardous Solid Waste Leak-Proof & Odor Anti-Diffusion
Silos and conveyors designed for continuous negative pressure operation at -50 to -200 Pa. - Anti-Corrosion & Anti-Caking
Electric heat tracing with ≥ 70% coverage to maintain hopper inner walls at ≥ 85°C against fly ash caking. - SRF/RDF Large Bulk Material Flat-Bottom Mechanical Discharge
Flat-bottom design utilizing 3–6m diameter hydraulic sliding frames to prevent fibrous jamming.
Thickness Advices
With depth, the lateral pressure applied by bulk materials on a silo wall grows nonlinearly. As such, the wall plates must be progressively thicker towards the base of the silo and thinner towards the top.
(Layer 4–7)
(Layer 8–10)