Bulk Equipment, Silos

How to solve bulk blockages

Material build-up is a common phenomenon in silos, reducing flow and creating a safety hazard. ESS Engineering has designed a solution.

Material build-up is a common phenomenon in silos, reducing flow and creating a safety hazard. ESS Engineering has designed a solution.

Silos, kilns and bunkers can have so much build-up that it can impede operations or even stop bulk material flow altogether. Build-ups can form as bottlenecks, bridges, arches, and rat holes. All of these result in reduced flow, storage capacity and dead material.

This material build-up becomes a safety hazard if it requires manual removal. Clearing the blockage from the outside may involve hitting the structure with a hammer, causing structural damage and presenting a manual handling risk.

In some cases, personnel may have to enter the structure to clear the build-up from the inside. This can pose several severe safety risks, including falls, engulfment, entanglement in machinery, exposure to high temperatures causing heat stress, and inhalation of gases and dust particles. In some instances, the dust in a silo may be explosive, which may limit methods of clearing blockages in bulk storage structures.

ESS Air Cannons are pneumatic bulk material flow aid systems that utilise the release of a volume of high-velocity, compressed air. This sudden release of energy is directed through a transition pipe into compacted material in a bulk storage structure to fracture blockages, restoring material flow and regaining storage capacity. In the bulk materials and handling sector, air cannons have numerous applications. They can quickly solve bulk flow problems in silos, hoppers, chutes and storage piles and are often used where vibration is not practical or other methods are too expensive.

Related stories:

While air cannons provide an effective method of dealing with bulk material blockages, the discharge of highly compressed, high-pressure air stored inside the vessel can cause severe injury or even death if not handled safely. Dealing with compressed air, in general, is hazardous, even when using smaller air compressors.

The ESS Engineering Services & Supplies air cannon system for bulk material removal is both safer and more effective than alternative arrangements. The system is available with both internal and external valves in four-inch and six-inch sizes. 

Air, which is stored in 40-litre, 70-litre, 150-litre or 250-litre receivers, escapes directly through valves into a discharge pipe to affect the area of influence during dispersal. ESS Air Cannons are designed to fill just before the air cannon is fired. This minimises the time the air cannon is charged, 

“We’ve taken out the biggest part of the risk, which is the time the vessel remains charged for,” Mick Hutton, ESS engineering manager, said. “For 90 per cent of the time, it lays dormant without charge, whereas traditionally, cannons are always charged with air and ready to go.

“In that scenario, it means you’ve got a pressurised vessel in an area where people frequent harbouring potential energy of 500 kilojoules that, if ruptured, could cause a catastrophe.

“With our air cannon system, we have developed a 150-litre cast vessel which effectively has an infinite life in terms of pressure cycles. It’s a more robust vessel than its rivals with no specific statutory inspection requirements as stipulated by AS3788.”

ESS valves have also been designed with only one moving part with no metal-on-metal contact. Fatigue-prone components that can cause premature failure have been engineered out. 

The air cannons can be remotely activated via a sequence controller that determines the fire time interval and the sequence of one or more Air Cannons, ensuring workers are not in the immediate vicinity when the tank is pressurised and firing.

ESS can help customers optimise air blasting outcomes through certain design features, such as tailored pipe designs or a chute mounting arrangement that will maximise the efficacy of a blast through proper design and firing sequence. 

ESS provides an end-to-end service for our products. The company will customise the air cannon design to a site’s application and install and service ESS air cannons. ESS also provides onsite safety inspection or hazard level assessments on pressure vessels. 

Send this to a friend