The Airlift Pipe Conveyor (APC) is a disruptive bulk materials handling technology. Resource Flow has changed the way dry bulk materials will be conveyed across mines, ports and sensitive areas such as agricultural / pastoral land and suburban environments.
With an estimated 10,000km of operational conveyor belts transporting minerals, it is estimated that capital and operating expenditure in the global mineral conveying market is $5bn per annum. Conventional belt conveyors represent the largest component of this market, but they have a big problem – idlers. Idlers:
- Are a massive source of friction that compounds over distance with respect to power draw, belt tension and specification.
- Introduce pinch points along the full length of a conveyor and are less safe.
- Increase control requirements through the introduction of trip wires along the length of conveyors.
- Increase the amount of structural steel required for supports and essential maintenance walkways.
- Wear out and require continual replacement.
In short, idlers make conventional conveyors extremely capital and operational expenditure intensive.
A company providing a conveying solution that removes idlers, yet is low cost, safe and environmentally friendly will have significant competitive advantage.
Resource Flow’s Airlift Pipe Conveyor (APC) provides this advantage.
Air supported conveyors are not new. They have been around for over 40 years and use jets of air to support the conveyor belt in lieu of idlers. By removing the idlers, friction is reduced and power costs, wear and maintenance are driven lower.
But air supported conveyors are expensive to fabricate and can be two to three times the capital cost of conventional conveyors.
Resource Flow has developed the Airlift Pipe Conveyor to overcome these high fabrication costs. The integral design of the APC enables fabrication by the lowest cost methods, by extrusion from HDPE or fabricated from thin wall steel pipe.
Conventional air supported conveyors use separate steel or aluminium fabricated air chambers, each chamber with its own dedicated air supply, to lift the carry and return sides of a conveyor belt. The APC reuses and recycles the low pressure levitation air, from blowers located every 300m, to enable the air slides and plenums to be contained within a single pipe.
A single pipe allows the APC an integral design enabling quick, continuous and accurate extrusion of the conveyor structure and slides from low cost HDPE. The lengths of pipe are connected by joiners that accurately align the internal air slides.
The APC can be located on-ground, buried, elevated or submerged underwater, offering new possibilities and alternative routes for haulage that are totally contained, environmentally friendly and require little maintenance.
The extruded HDPE offers many advantages:
- Able to be buried in trenches on levelled bedding sands.
- Able to be laid on levelled ground either with expansion curves or expansion joiners.
- Can be coextruded with a solar reflecting outer polymer.
- Able to be suspended by catenary supports.
- Smoothest finish to the key perforated slide.
- Long minimum allowable bend radius matching the minimum conveyor bend radius.
- Low coefficient of friction if the belt touches the slide.
- Low thermal conductivity minimising condensation.
The conveyor belt within the pipe has no contact with moving parts resulting in zero maintenance between the pulleys at the head or tail end. As a result it does not require inspection, so there is no requirement for walkways, hose reels or safety protection. It is sealed so emits no dust or noise.
How the AirLift Pipe Conveyor Works
The patented integral design is the key to the low cost of the APC.
Air is introduced into lower plenum by a low pressure blower. A portion of the air is used to levitate the return belt. The expended air escapes at the sides of the belt and joins the remainder of the air bypassed to the carry belt plenum. The air is reused to levitate the carry belt and burden while the expended air escapes at the sides of the belt to the pipe above the burden. The expended air is recycled (and filtered) to the blower.
Air is contained in the carry belt plenum by using seals (not shown).
The APC is up to 50% lower capital cost, up to 50% lower operating cost and offers many environmental advantages over conventional conveyors. The APC also introduces new opportunities for alternative transport corridors in environmentally sensitive locations, or where traditional conveyors have been uneconomic.
The APC can be used to:
- Replace short haul (<30km) trucking of bulk materials.
- Replace rail lines or overland conveyors passing through sensitive locations.
- Enable remote stockpiles with buried conveying through suburbs.
- Enable submerged conveying to remote offshore ship loaders without dredging.
- Enable the uptake of alternative mining techniques including In-Pit Crushing and Conveying (IPCC) with in-spoil sacrificial conveyors.
- Replace mine haulage, product handing and rail loop interfaces.