Cyclone confusion

[Grant Wilkinson]

Help, please!

I'm looking to upgrade my dust collection system and have been reading all I can about makes and models. I am confused by some of the statements made in various threads on the Creek. Specifically, people say that not much dust reaches the filters of this unit or that. I thought one of the major advantages of a cyclone was that it separates the heavier material from the dust. The heavier falls into the bin below the cyclone and the dust is pushed through the filters. This was, we don't need huge collection bins that serve only to collect dust.
If that is the case, there must be considerable dust from, say the operation of a table saw, and most or all of it is going to the filters.
If I'm wrong about how the cyclone works, it seems to me that all we need is a large vacuum cleaner that sucks up everything and dumps it into a drum of some sort. Why have a cyclone if it doesn't do anything but suck shavings and dust?
Am I missing something?

[Eric Gustafson]

The cyclones are designed to force the air and dust down towards the holding can below and separate as much of the dust as possible from the air, which carries on, up to the impeller and on to the filters. A perfect cyclone would separate the dust from the air 100% and no dust would make it to the filters. There is nothing perfect under the sun, of course, but they do a very good job.

[Tom Veatch]

... it seems to me that all we need is a large vacuum cleaner that sucks up everything and dumps it into a drum of some sort.


That's a pretty good description of the operation of a single stage dust collector.



Why have a cyclone if it doesn't do anything but suck shavings and dust?
Am I missing something?

Maybe I'm missing something also, but what else would you want it to do?

One benefit of separating out as much of the fines as possible before it gets to the filter is that the filter cleaning job is needed much less frequently. In the ideal case, you would need no filters at all.

For me, a cyclone would have no appeal if all it did was separate out the chips and pass the fines. Then I'd have two buckets to empty instead of just one.

[Bill Wyko]

I'd like to add that the cyclonic action creates inertia to the particles which makes even the smallest pieces heavy enough to end up at the bottom of the canister. The only dust to make it to the filters is so small that it follows the air up to the fan and to the filter, A very fine particle. A dyson on steroids.:D

[Dale Lesak]

The air flow is what makes the cyclone type DC work. The in coming air /sawdust are spun inside of the housing. centrifugal force makes all the sawdust go to the outside and then fall down into the holding tank. the air is pulled from the cyclone from the center and there for should be free of most sawdust / Dust. The faster the air flow the faster the spinning action the more centrifugal force and if everything else is right the cleaner the air going to the filter. :)

[glenn bradley]

A single stage pushes everything to the bag/filters. Frequent bag emptying.

A trashcan separator catches most of the heavy stuff through a cyclone-like action; the spinning slows the airspeed and the heavy stuff falls down. Infrequent bag emptying.

A cyclone also uses the spinning pathway to slow the air enough for the heavy stuff and a lot of the light stuff to fall out with a lesser impact on the airflow. The small amount of fines that do make it through get caught in your filter which needs to be cleaned very seldom as very little gets to it. Occasional filter cleanings based on use.

[Bill Wyko]

Keep this in mind. Less material getting to your filter means less volume of material trying to pass through your filter. The cyclone filters will filter I think .02 microns. If you had a lot of fine dust getting to a filter like that, it would plug up in no time. But because the inertia:p makes most of the material end up in the can and not trying to get through your filter, it makes it a very effecient system. You have all that filter surface area and very little material reaching it. IMHO it's the best filtration system in the biz at this point in time. BTW I don't even have a cyclone. I have a jet with a canister filter. I hope this helps.:D

[Eric Gustafson]

We really need a physics proffessor to understand how a cyclone really separates the air from the dust! :confused:

The only problem is, the professor would be the only one who understands what is said! Sufficient to state that the cyclone uses newton's law, acceleration, mass, inertia, vortex and other mumbo jumbo! But it works!

Thank goodness I do not have to understand why the sky is blue to enjoy it.:rolleyes:

[Grant Wilkinson]

Thanks to you all for this education. Now, all I need to do is settle on make and model.

[Troy Cleckler]

Thanks to you all for this education. Now, all I need to do is settle on make and model.

Why not build your own. I did and it works great. Got the plans from WOOD mag and bought a 2hp DC from Harbor Freight for about 120.00 and only used the motor to run my system. Works Great! Only having blast gate problems and I'm looking into making my own. Here's a pic of mine.
http://i167.photobucket.com/albums/u154/tcleckler/WoodProjects002.jpg

[Paul Johnstone]

OP:
Check out Bill Pentz website.

Here's the short answer, you want as much fine dust as possible to end up in the bin. The filters are very efficent, but don't get 100% of the dust. Also, excessive dust particles also damage the filters.

The big benefit of a good cyclone is that almost all of the unhealthy fine dust ends up in the trash can/bin, and not in the air. This protects your health.

It's really amazing. After I switched to a cyclone, I didn't even have the "sawdust" smell in my shop anymore. Although I must warn you that there's also some work to be done at the dust hoods/collection points of the tools to get full benefits.