When cement or other fine powdered materials are first conveyed into a storage silo or bin, it is actually a highly aerated mixture of air and particulate and in this state it flows quite readily.
However, as the cement or other powder settles the solid particulate and air separate resulting in a decrease in volume and an increase in bulk density. In this de-aerated state powders behave more like a single large solid structure rather than a fluid-like mixture. This can result in bridging and rat hole formation, both of which prevent smooth flow.
By replacing the naturally lost air through aeration, the air to particulate mixture ratio can be maintained, thus maintaining the fluid like characteristic of the aerated powder.
Monitor offers two alternative aeration devices.
- The Air Pad, a cost-effective solution to many material flow problems. These air pads are ideal for a variety of finely ground dry materials – such as flour or cement – or any material that tends to pack while in storage and then cling to the walls of the bin.
- The Evasser, bin aerator from Monitor Technologies is a device used to promote the flow of dry bulk powders from a storage vessel without the noise and damaging vibration caused by pneumatic or electric vibrators. The Evasser aerator is small, compact and capable of aerating many types of bulk powders and granular solids in bins, hoppers and silos. The Evasser can discharge air up to 80 psi (5.5 bar) to move settled materials. Once material is flowing the Evasser can be used to maintain flowability of material with a constant 2 to 5 psi (0.14 to 0.35 bar) supply of air.