Bridging Material

One of the major problems with dust collectors is bridging in the hopper. Bridging is when dust builds up above the dust discharge flange, forming a “bridge” that prevents dust from leaving the hopper. The phenomenon typically happens in applications with sticky, fibrous, and irregular shaped materials. If bridging isn’t caught and managed properly, it can cause dust to fill up the hopper and affect the removal efficiency of the attached dust collector. Dust collector hoppers are designed to collect dust rather than store it, and dust should be removed from the system when it travels through the airlock valve.

There are multiple ways to break up dust bridges, but vibrators and air cannons are two of the most popular reactive solutions. We recommend that if you know your material bridges, its best to be proactive and design the hopper and the airlock to prevent bridging before it starts.

Large rectangular openings in airlock valve designs are an ideal choice to help prevent bridging. Square and round openings in airlock valve design unfortunately create the best environment for material bridging to occur, but a rectangular opening doesn’t support the center of a bridge, thereby causing it to fail. In a dust collector hopper, this a good thing!

The Aerodyne Mighty Whopper rotary valve is a custom valve designed for rectangular hoppers. The Mighty Whopper has a robust construction for challenging applications such as fiberglass.