How profile construction differs from sheet construction
In a sheet-metal silo, sheets or shell courses form the load-bearing shell. In a profile design, the wall consists of extruded aluminium elements shaped by an extrusion die. The cross-section may include ribs and cavities that contribute to shell performance.
The main advantage is the ability to design both the silo’s external form and the wall cross-section itself. Profile geometry can be tailored to stiffness, connections between adjacent elements and additional functions.
Profile technology does not eliminate structural calculation. Bulk material pressure, vacuum, wind, snow, seismic effects, supports and local equipment loads must be assessed for each project.
Why aluminium is used for profiles
Key aluminium profile properties include corrosion resistance, low weight, machinability, complex cross-section capability and recyclability. For silos, low structural weight combined with natural atmospheric corrosion resistance is particularly valuable.
Extrusion produces long elements with repeatable cross-sections. Sespel’s materials list profile lengths up to 30 m, circumscribed diameters up to 540 mm and cross-sectional areas from 0.43 to 700 mm². These figures describe stated production capabilities and are selected for each product.
Storage applications also require assessment of alloy compatibility with the contents, hygiene requirements, product abrasiveness and protective surface treatment needs.
Forming the silo tower shell
Vertical profiles form a cylindrical shell. At the top and bottom, it connects to the roof, discharge cone and support ring. These transitions create local loads, so joints are designed together with the profile rather than as separate additions.
A profile cross-section can serve as both shell and stiffening ribs, allowing wall stability to be controlled without simply increasing material thickness.
The design must also include access hatches, filling and dust extraction connections, level sensors, ladders, service platforms and process equipment mountings. Every opening or additional component affects local shell strength.
Additional uses for internal profile cavities
An interesting feature of a profile wall is the structural use of its internal cavities. Openings through profile elements can provide air purging and agitation of bulk material.
Empty cavities may also be filled with materials that modify the wall’s physical and mechanical properties. The filler and filling arrangement must be designed for the required stiffness, insulation or other structural performance.
Profile construction may reduce deformation risk under vacuum compared with a sheet-aluminium silo. In a real project, this advantage must be verified by stability calculations for the specific cross-section and shell.
Diameter, height and useful capacity
Silo capacity cannot be selected independently of diameter and height. Different proportions can provide the same volume, but change wall pressure, footprint, filling height and transport and installation arrangements.
Profile silos can cover a wide size range. The combinations below illustrate the scale of the concept rather than a fixed range applicable to every project.
| Diameter | Example capacity | Cylindrical section height A |
|---|---|---|
| 2,400 mm | 23 m³ | 4,500 mm |
| 3,000 mm | 100 m³ | 13,250 mm |
| 3,500 mm | 220 m³ | 22,000 mm |
| 4,200 mm | 355 m³ | 24,500 mm |
| 4,900 mm | 380 m³ | 22,000 mm |
| 8,050 mm | 960 m³ | 22,000 mm |
| 11,000 mm | 2,050 m³ | 22,000 mm |
| 16,500 mm | 4,700 m³ | 22,000 mm |
Define the product before the silo geometry
Correct silo selection requires both the desired stock volume and bulk material properties: density, particle size distribution, moisture, caking tendency, abrasiveness, flowability and compatibility with aluminium.
These parameters determine cone angle and geometry, outlet size, aeration or vibration needs, design shell loads and discharge rate.
The same volume of light polymer granules and dense mineral powder produces very different product masses and load-bearing requirements. Capacity alone is therefore insufficient for selection.
Data required for silo design
The specification normally includes useful capacity, product properties, daily throughput, filling and discharge methods, temperature, pressure or vacuum, site climate and dimensional constraints.
Additional equipment is defined: filters or dust extraction, level gauges, aeration, safety devices, ladders, platforms, hatches, piping and automation.
For profile construction, this stage also selects profile cross-section and orientation, joining method, roof and cone connections and use of internal channels. This integrates extrusion advantages into the engineered system rather than merely replacing a sheet wall.
Industrial implementation and place in the silo range
Our website presents aluminium silos for industrial bulk storage. Special extruded-element construction develops this concept and offers a different way to form the load-bearing shell.
Profile construction is particularly attractive where substantial height, low shell weight, functional internal channels and custom geometry are needed together. Economic feasibility depends on production volume, extrusion tooling cost and installation requirements.
The best manufacturing method may differ between a one-off project and a production range. Profile and conventional sheet-metal silos should therefore be compared over the full project life cycle.
Sources and technical materials
- “Aluminium Profile Silo Towers” presentation, Sespel, 2024
- Product materials in the Sespel website’s Aluminium and Stainless Steel Silos section
The applicable regulatory requirements depend on the product’s intended use, industry, jurisdiction and project specification.