---
title: "Silo"
description: "A silo is a large vertical vessel for storing bulk solids — cement, fly ash, lime, biomass pellets, fertilizer granules, food powders, mining concentrate. Silos range from a few cubic metres to tens of thousands of cubic metres and are typically cylindrical with a conical discharge bottom feeding into a single outlet or a cluster of outlets."
canonical_url: "https://sylio.co/glossary/silo"
last_updated: "2026-06-28T02:29:33.203Z"
---

A **silo** is a large vertical vessel for storing bulk solids — cement, fly ash, lime, [biomass](/glossary/waste-to-energy) pellets, fertilizer granules, food powders, mining concentrate. Silos range from a few cubic metres to tens of thousands of cubic metres and are typically cylindrical with a conical discharge bottom feeding into a single outlet or a cluster of outlets.

## Why silos bridge

Most bulk solids show some degree of cohesion. Under the gravitational load of metres of stored material, the cohesive bond is enough to form a stable arch above the discharge outlet ([bridging](/glossary/bridging)) or a narrow flow channel surrounded by a hardened mass ([rat-holing](/glossary/rat-holing)). The longer material sits in the silo, the more it consolidates and the harder it is to restart flow.

## Sonic horns as flow aids

[Sonic horns](/glossary/sonic-horn) installed at the silo discharge cone provide continuous low-amplitude vibration that prevents cohesive structures from forming. A single horn typically covers the discharge cone and the lower 2–5 metres of the silo wall. Multiple horns address larger silos or persistent rat-holing zones.

Compared with [air cannons](/glossary/air-cannon-air-blaster) and [bin vibrators](/glossary/bin-vibrator):

- No structural impact on the silo
- No discrete blast moments that introduce air pockets into the discharge
- Lower total air consumption per unit cleaning effort
- Single mounting versus arrays of cannons

## Related terms

- [Hopper](/glossary/hopper)
- [Bunker / coal bunker](/glossary/bunker-coal-bunker)
- [Bridging](/glossary/bridging)
- [Rat-holing](/glossary/rat-holing)
- [Sonic horn](/glossary/sonic-horn)