Posted on June 15th, 2018 by Carrier Vibrating
Storage silos are used in almost every industry to store materials safely until they are needed for use, but all materials and all silo designs are prone to some sort of silo blockage, preventing the material from flowing freely when needed. Keeping silo material moving freely and preventing blockages improves the quality of the product being stored and prevents dangerous environments for workers. Carrier Vibrating Equipment offers a line of vibrating bin dischargers to help with this common problem and keep material flowing at a first in first out rate.
There are three main ways that a storage silo can become blocked from the materials in it: rathole, bridging, and classification.
Rathole
This is caused when the material packs in along the outer edges of the silo, clumping together and refusing to flow, with only a thin tunnel along the middle emptying product out. The pressure continues to build when this happens, packing down the walls tighter and making the problem worse as time goes on. Depending on the material and environmental conditions inside the silo, it is possible for it to solidify into a hard mass that requires manual cleaning.
Bridging
When material is dumped into the storage silo it exerts pressure on the material under and around it, and with some materials, this surrounding pressure can cause a structural bond. This bond results in a bridging effect where the bottom of the bridge empties but a dome arch remains, preventing any further material from flowing. As more material is dumped on top of the bridge the pressure exerted increases and the bonds holding the bridge together will actually become stronger.
Classification
When material is initially poured into the storage bin it has the natural tendency to separate by particle size, with larger particles collecting around the outside rim and the smaller particles clustering around the center. This results in the flow being made up of unevenly sized particles, as the small material flows first and the larger pieces flow last, instead of a plug flow system. This uneven mixing can create quality control or manufacturing issues if the final product was designed for the evenly mixed particle sizes.
A Carrier vibrating bin discharger attaches to the storage silo outlet and provides pulse vibrations on a timer, which regularly mixes and agitates the material inside. This helps keep it evenly mixed and prevents it from settling and compacting. The vibrations ensure that the stored material moves in a first in first out flow, keeping quality intact and reducing the need for workers to perform dangerous cleaning.
Having issues with material flow in your storage silos? Contact a Carrier Vibrating Equipment engineer today to see how we can help you prevent these common problems.
