---
title: "Discharge cone"
description: "The discharge cone is the converging lower section of a hopper or silo that funnels stored material to the outlet. The cone's geometry — angle from vertical, surface finish, outlet diameter — is the single most important design variable controlling whether the vessel delivers mass flow or funnel flow."
canonical_url: "https://sylio.co/glossary/discharge-cone"
last_updated: "2026-06-28T02:29:32.775Z"
---

The **discharge cone** is the converging lower section of a [hopper](/glossary/hopper) or [silo](/glossary/silo) that funnels stored material to the outlet. The cone's geometry — angle from vertical, surface finish, outlet diameter — is the single most important design variable controlling whether the vessel delivers [mass flow](/glossary/mass-flow-vs-funnel-flow) or [funnel flow](/glossary/mass-flow-vs-funnel-flow).

## Design rules of thumb

- **Steeper cone** (smaller angle from vertical) — more likely to deliver mass flow
- **Smoother wall finish** — less friction at the wall — more likely mass flow
- **Larger outlet diameter** — greater margin against [bridging](/glossary/bridging)
- **Outlet at least 6× the largest particle dimension** — minimum to avoid interlocking

For cohesive powders, the cone needs to be steeper than 70° from horizontal and the wall finish must be smoother than the material's wall-friction angle to achieve mass flow.

## Acoustic-cleaning duty

[Sonic horns](/glossary/sonic-horn) are most commonly mounted on the cone wall — either through a side flange just below the vessel cylinder or at the cone-to-cylinder transition. This positions the horn close to the most arching-prone zone while keeping it accessible for maintenance.

## Related terms

- [Hopper](/glossary/hopper)
- [Silo](/glossary/silo)
- [Mass flow vs funnel flow](/glossary/mass-flow-vs-funnel-flow)
- [Bridging](/glossary/bridging)
- [Sonic horn](/glossary/sonic-horn)