Storage of fragile products: the innovative chute silo for salt pellets

Background

The challenge of the project was to design a storage solution for fragile products capable of breaking this reliance on just-in-time supply without compromising the physical integrity of the salt pellets. The technical solution took the form of a novel flexible silo, fitted with an internal slow-release mechanism.

By incorporating a chute designed to the client’s specifications, Syvrac enabled the client to stabilise its production line. This system protects the material from attrition throughout its descent, ensuring consistent finished product quality and a new level of logistical flexibility for the site.

The problem of breakage of friable products in silos

The limitations of conventional vertical storage for salt

In a standard silo, filling is generally carried out from the top, allowing the product to fall freely to the bottom or onto the existing pile. For compressed salt pellets, this free fall is destructive. The impact on the floor or against the walls shatters the edges of the pellets, creating salt dust (fine particles) which detracts from the product’s appearance.

Before Syvrac stepped in, the client had no solution for accumulating these pellets without damaging them, which made their entire production line vulnerable to even the slightest stoppage of the boxing machines.

The Syvrac innovation: the flexible silo fitted with a stainless steel chute!

Design of a bespoke, fabricated chute

To meet this specific requirement, Syvrac has developed a discharge chute made of stainless steel, 30 cm wide and fitted with guide flanges. This spiral-shaped, fabricated chute was made to measure to suit the height of the silo (3.50 m for this project) .

Its internal design allows the pellets to descend by gravity, but without sudden acceleration, thereby preserving their integrity. This technical innovation demonstrates the adaptability of flexible silos to complex industrial products that were previously confined to much more space-consuming flat storage systems.

Performance and adaptability of the buffer storage solution

From just-in-time to the peace of mind of buffer stock

The installation of this flexible silo has enabled the customer to move away from a permanent just-in-time system. By having secure intermediate storage capacity, the factory can now continue production even if the packaging line is undergoing minor maintenance.

The complete elimination of breakages during filling ensures that the stock built up remains 100% saleable. This new flexibility reduces operational stress and optimises the site’s overall equipment effectiveness (OEE).

FAQ

How can fragile products be stored in a silo without breaking them?

To store friable materials, the kinetic energy associated with free fall must be eliminated. The solution is to guide the product along a gentle slope, such as a spiral chute, in order to limit the speed of descent and guide the material to the filling point without any sudden impact.

Storing fragile products such as salt pellets requires a rethink of the internal dynamics of the silo. Rather than allowing gravity to act unchecked, an inclined chute is installed to reduce the vertical trajectory. By sliding down a smooth stainless steel wall, the product maintains a constant, low speed. This not only reduces direct breakage upon final impact, but also minimises attrition — the friction between particles — which is often responsible for the formation of unwanted dust in tall silos.

How do you install a guide chute in a flexible silo?

The installation relies on an independent support structure fixed to the silo’s steel framework. To allow this rigid structure to be inserted into a flexible shell, the silo fabric is fitted with a technical Velcro fastening, ensuring a watertight seal after installation.

Inserting a stainless steel chute several metres long into a bespoke fabric silo requires a high degree of precision during installation. The chute is secured to the external supporting structure, thereby avoiding any through-fixings that could create retention zones. The Velcro system on the fabric allows the silo to be opened easily for installation or maintenance. Finally, the system provides airtight protection against ambient humidity, a critical factor in salt preservation.

What are the advantages of a flexible silo with an internal chute?

This process combines the economic advantages of a fabric silo with the mechanical protection of a slow-release system. It is a scalable solution, capable of adapting to all types of silos, up to heights of 5.50 m, for a variety of sensitive products.

In addition to the benefits for product integrity, this solution is particularly versatile. The principle of the bespoke chute can be applied to other sectors such as the food industry for the storage of coffee beans or fragile confectionery. The flexible silo also has the advantage of being easily installed in existing buildings without requiring heavy foundations, thus offering a very favourable cost-performance ratio compared to rigid silos.

Which transfer system should be chosen for brittle products?

For fragile products, the combination of a belt conveyor for horizontal transport and a chute for vertical filling is ideal. These complementary passive methods preserve the structure of the material, unlike pneumatic systems.

The choice of transfer method upstream of the silo is crucial. At our client’s site, the chute is fed by a belt conveyor. This system transports the pellets without any friction or compression. Once they reach the top of the silo, they are gently deposited onto the chute. This ‘conveyor + chute’ combination constitutes the logistics chain that is the gentlest for preserving the physical characteristics of sensitive products.