Skip to main content
A reliable and controlled silo discharge system


Rotoflo was devised at Portasilo more than two decades ago as a market-leading silo-discharge unit.

Now an exciting addition to Severfield’s product solutions, this exceptional silo discharge system has been continuously developed and improved to ensure it remains the leader in silo discharge and material handling solutions technology. It’s purpose as a discharge solution for silos and hoppers is to prevent powder flow problems and bridging of materials in storage, providing a reliable, consistent and controlled rate of discharge.

Silo discharge solutions for powder bridging

Rotoflo is designed to help with material handling ensuring that silo discharge is free-flowing and controlled, when handling a number of diverse materials. Rotoflo is designed to help prevent powder bridging in silos and hoppers.

What are silo discharge systems?

Silos are generally used for the storage and discharge of powdered or granular bulk solids and a silo discharge system is designed to aid discharge of materials quickly and efficiently, eliminating the risk of powder bridging or blockage.

Rotoflo silo discharge units can be built in or retro-fit to existing vessels and allow materials to be safely and efficiently discharged from a silo or hopper. With multiple configurable outlets, a Rotoflo silo discharge unit can uniquely both reduce the risk of material flow problems within a vessel and provide a controlled rate of discharge to multiple downstream processes.

What is powder bridging?

Powder bridging is when the materials in a silo or hooper become interlocked and forms a stable arch or rat-hole over the designated outlet. When powder bridging occurs, the materials stored in the silo become trapped. Silos should be fitted with an appropriate discharge aid to avoid this and ensure correct and efficient discharge.

What causes powder bridging in silos and hoppers?

The common causes of powder bridging include:

  • Vessel geometry including hopper angle and outlet size.
  • Wall friction – friction between the material being stored and the vessel wall material.
  • Internal friction – friction within the material being stored.
  • Consolidation of the material within the vessel due to materials self-weight.
  • Consolidation with time of the material within the vessel.
  • Attraction of the material particles (electrostatic or Van-der-Waals forces)
  • Liquid bridges due to moisture within the stored material or adsorbed from atmosphere.
Severfield Rotoflo

How can you prevent powder bridging in silos and hoppers?

With Rotoflo, you can simply and effectively prevent power bridging and discharge problems in silo systems without the need for vibration or aeration. Rotoflo can help prevent powder bridging by offering:

  • Large diameter active silo outlet
  • Elimination of dead space where contents may consolidate.
  • Low headroom design maximising silo contents
  • Control of discharge rate
  • Consistent feeding over a wide range of throughputs
  • Up to four feed points providing a flexible solution without additional equipment
  • Designed to process a wide range of materials
Severfield Rotoflo

To contact our Rotoflo team, you can email and our order form is available to download below.