Dust Collection Cyclones?

[Keith Outten]

After reading all of the posts here concerning cyclones I was wondering if a cyclone would be beneficial to those of us who do not use bags with our dust collection systems. The problems of very fine dust particles in the air is lessened when you exhaust directly to the outside. Most woodworkers don't have this luxury, neighbors who are in close proximity to your shop would definitely kill the option.

For those of us who can dump directly to the outside would a cyclone improve this type of system? I think I already know the answer to this question but have to ask...you never know. Would an exterior cyclone provide any performance improvement or capability?

I have visited Terry Hatfields web site and recently read Bill Penz's article concerning the hazards of dust in the workshop. I have to admit that Bill's article got me in gear and I have spent the last three days doing a massive cleanup and removal of all unnecessary lumber and equipment from my shop, thus enabling me to keep it clean. I even relocated both of my lumber racks to another building and of course reaped the added benefit of reclaiming shop space along with sore muscles from moving 6000 pounds of lumber and plywood.

[Mac McAtee]

I have a DC system with cyclone. The cyclone is on the second floor of my workshop (two story garage). The discharge of the cyclone is about 4' long and goes directly outside into a small grove of cedar trees. I have never seen any sign of dust on the trees. I figure that if there is any dust it is so small that the trees catch it and when it rains it gets washed off of the trees to the ground under them.

If you do this, you need a flapper on the end of the discharge pipe or birds will build nests in your cyclone pipe. I made a simple sheet metal flapper with a hinge and a counter weight on the end of a piece of all thread rod. I "tuned" the counter weight so that the flapper stays closed when the system is off and tips open very easily when it is running. I wanted to consume as little of my airflow as I could to push the flapper open. I would be happy to take a picture and post here if you are interested in seeing it.

The only drawback that I see from this is that the whine of the DC system is blasted out with the air. One day I have to come up with a way to cut the sound a little. I would guess that a curved blade impeller would do that but can't afford to buy one just to see what happens.

[Jim Becker]

The chief benefit to adding a good cyclone to your system, even though you are venting to the outside, is that you will be controlling the discharge of the larger chips and dust. You can more easily use or dispose of them, rather than developing a large pile of material outside of your shop that can attract various forms of vermin with anywhere from 4 to 8 legs. The bottom line is putting the cyclone inline will make the air stream you're ejecting to the great outdoors "cleaner".

The downside is that it potentially will slightly reduce the performance of your blower, but this would be minimal if things are designed correctly.

I like the idea of locating the cyclone completely outside of the building...and would do so if I could. If the blower is also located outside, the noise reduction can also be substantial.

One other thing that needs to be said for the benefit of the general audience...exhausting outdoors can be dangerious if you are heating your shop with any type of flame unless you have an equal or greater fresh air flow into the shop at the same time. Backdrafts of heater vents, etc., can kill you!

[Scott Coffelt]

Add to the fact that it is not very environmentally friendly to just exhaust out into the air. granted it is a very condensed verison of what was ther in the first place.

[Ken Frantz]

"The discharge of the cyclone is about 4' long and goes directly outside into a small grove of cedar trees."

Instead of discharging into the trees, would it help to discharge into an open 55 gal drum with water setting in the bottom and just letting the air from the cyclone just blowing on top of the water to catch most of the fine dust?????

[Dennis Peacock]

Is the amp load on the motor. Some restriction on the outlet side helps to keep the motor amp draw at a lower rate. So unrestricted outlet pressure can inflate the amp load on the motor.

[Mac McAtee]

Let us try this again. The discharge from my cyclone goes out the shop wall and blows into a grove of cedar trees. Cedar trees are green, wood dust is usually a lighter color. I have never seen anything coming out of that discharge pipe nor have I ever seen any sign of any white or light colored dust on the cedar trees. The point is that the cyclone gets most of the stuff and if there is anything that makes it through the cyclone, you can't see it.

As far as a barrel of water goes, beyond the cedar trees is a 12 acre mill pond.

[Dennis Peacock]

< As far as a barrel of water goes, beyond the cedar trees is a 12 acre mill pond. >

That orta do just fine for a small water barrel....!!! :-)

The point you are <b>really</b> making is that a cyclone is usually effecient enough to capture almost every little bit of "stuff" from each machine.....I will whole heartedly agree..!!

[Mac McAtee]

Dennis,

By George I think he's got it!

That is my point. What ever is making it through the cyclone, I wouldn't want blowing back into my workshop. I know there must be something, very small particles, and I wouldn't want to be breathing them in an enclosed area. That is why I put in a DC system.

There seemed to be some concern about the effect on the environment by discharging to the great outdoors. This past winter we had two very good ice/snow storms. On my property there was and are 20-30 trees down, plus what would amount to several dump truck loads of limbs. Those limbs and trees will sit in the woods until they rot into ground litter. I don't see a teacup or two per month of some invisible wood powder as having any effect at all on the environment. If I were living in a large city that had been paved over with concrete, I doubt that anyone would be able to find a trace of what ever is coming out of my DC system on the ground.

My only concern with the system I have is the whine from the blower being ejected out of the building in the air-stream. A neighbor that lives 500 yards away, that possibly could be sensitive to high pitch sound, could possibly be uncomfortable with the sound. I just don't want to find out when they complain and I do not run the system at odd hours of the night or early on weekend mornings. The cedar trees limbs and foliage do help block the sound from traveling and that may be a sufficient muffler.

[Scott Coffelt]

Why don't you build a muffler. Terry put plans of one I designed on his web site at Dust Eliminator. You could add it in line before you go outside depending on spacing or put it outside but make sure you angle it downword to avoid water getting into it. The longer you make it, I bet the more it will damping the sound. Terry tested the design and it lowered the sound by 11db. Also if you do put it outside, I would install a screen ont he end to keep the birds and other things from making a home... or at least temporary home until the DC gets turned on.

Could you imagine the poor bird who thought he had find the ideal place to build a nest.... swoosh, he is sent into the ground at mach speed... thump!!!!!

[Paul Kunkel]

I can't hear it at home (150ft away) and have a light that goes on with the cyclone so I know it's running. The roof of the shop is dark brown propanel and if there were any wood dust being exausted it would show. When I use the dual drum i do get some though. When in heating season, I run it through the filter to save heat. Never thought about the bird thing......don't think they'd have time to build a nest without it being blown to the next county.

[Mac McAtee]

Scott,
Just what I was looking for. Went to Terry's web site and printed out the article. Great and clear instructions. Next time I start tampering with my DC system I'll build it and give it a shot.

Do I understand correctly that you feel this will cut down on the whine that comes from the blower? I don't mind the air or motor noise just the slight siren sound that comes from the impeller pushing air.

[Jim Becker]

Originally posted by Mac McAtee
Do I understand correctly that you feel this will cut down on the whine that comes from the blower? I don't mind the air or motor noise just the slight siren sound that comes from the impeller pushing air.

In my experience, the muffle will help to reduce the "roar" of the air moving to your filters (or external outlet). I found that I had to put my cyclone in it's own closet to reduce the actual blower noise. Having both the blower and filters in my closet reduced the sound level the most. Unfortunately, when I had my electrical upgrades done, the location of the panel in the same closet required that I move the filters outside of it to pass inspection. (Code for access to the panel) Now that is all over and done with, I may move the filters back inside...hee hee