Will a Boost Fan Step Up Dust Collector Capacity?

A woodworker adds a new piece of equipment, and wants to know whether adding a boost fan will enable his existing dust collection system to handle the increased requirement. April 17, 2009

I have a new 5 head moulder coming and my dust collector is not big enough. I was wondering if anyone has knowledge about using a separate fan at the moulder and connecting it to my present dust collector.

Forum Responses
(Dust Collection and Safety Equipment Forum)
From contributor S:
It will all depend on the type of system you have. All commercially sold systems are designed to certain performance curves. Whatever type of system you have is designed to handle a certain amount of air flow and dust removal. By adding more HP or air flow doesn't mean greater performance. You can certainly add an additional blower to pull the chips out of the moulder. But can your system handle it? You also have to look at the amount of suction the moulder needs and the size of the main duct. You will probably need somewhere around a 12" main to handle the CFM's and have enough velocity to carry the dust. If you are planning on running a lot of material through the machine then you need to consider what you plan to do with the dust. It can add up to a good amount of waste in a very short time.

From contributor O:
If your collector is an older / used one try changing the filter bags. I just got new ones and had them made as tall as possible and my collector now works 100 times better. You will not believe the difference.

From contributor C:
The only situations where I have seen the boost fans operate successfully is if the boost fan is minimal compared to the overall central collection fan. Example, a small wide belt sander with a 6" outlet is 75 feet from the main trunk which is at least 18" diameter. A small 2 hp blower at the sander would throw the dust most of the way to the trunk and when induced will not disrupt the overall performance. This is assuming that the central blower is a little over taxed and could not pull effectively 75 feet away.

That being said, a couple of options when a large moulder is purchased. Some moulders end up requiring the same volume as when the standard floor machines are operating. Therefore, run moulding and close off everything else and vice versa (assuming the collector is a two stage set up which is required for a moulder). Otherwise, get a dedicated two stage for the moulder with sufficient storage capacity, hopper or multi drums. You will probably need a 10 horse power for that moulder. Last option is a new two stage collector to handle moulder and simultaneously operating floor machines. A two stage collector is critical for a moulder. If a single stage is used and all of the chips hit the fan, the unit will not last that long.