Exterior Cyclone Collector with Air Return to Shop

Thoughts on locating a dust collector's cyclone bin outside the building for easy waste collection and disposal, while arranging for filtered air return to the workspace for energy conservation. December 29, 2008

Question
I'm considering an Oneida Cyclone and was considering separating it from the shop (either placing it outside or in a closet of some kind) and venting it outside. This does mean I need a way to get fresh air back into the shop, and since I live in New England, it would be nice not to keep blowing all the heated air outside.

I was looking at HRVs (Heat Recovery Ventilation) which will capture 75-80% of the heat from the outgoing air and give it back to the incoming air. Problem is all the economical models I've managed to find claim to handle ~200 CFM and the Oneida is rated at 1349 CFM. Does anyone have experience with doing this?

Forum Responses
(Dust Collection and Safety Equipment Forum)
From contributor J:
The most common method is to place the cyclone outside the building with a return and the fine filters inside the building. If you want to be clever you can put a gate on it. In the warmer months the fine dust blows out instead of coming back inside the shop. Less fine dust in the shop and will prolong the life of your filters. In the winter months the warm air returns to the shop through your filters. Plus all year long the bulk of your dust and chips are outside, which should be easier to deal with.

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From contributor D:
I have done this with Oneida equipment in a 1,000 s/f one man shop. I built a phone booth sized exterior access closet and mounted the fan and cyclone in the upper area, and built an air-tight collection chamber below that would hold a large pickup load of shavings. The return air was filtered and went back into the shop. The access door was at pickup height, and my horse husbanding neighbors would come and clean the bin out as needed.

One warning: if you exhaust outside with closed doors and windows, but heat with wood, gas, propane or oil, your flue will not exhaust, but will send in enough carbon monoxide to kill you. Return your air to keep a balance, and your warm air.

Oneida is not much help on this design - they like that little 30 gallon drum. I'd fill it in 30 minutes. Air-tight collection chamber is the key. Any leakage and the shavings will blow past the cyclone and into the filter bags.