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To use a cyclone or not

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Forum topic by ChrisBarrett posted 09-23-2015 09:02 PM 1154 views 0 times favorited 20 replies Add to Favorites Watch
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ChrisBarrett

99 posts in 519 days


09-23-2015 09:02 PM

Topic tags/keywords: question

So I have been piecing together my dust collector for my garage shop. So far I have a Leeson 3hp motor with a dayton blower. It pulls 1040 cfm right at the inlet with no ducting. My plan is to run 6” ducting to all the machines. I also plan on venting it out the wall.

Given the fact that I am not using a filter inside the garage, does it even make sense to use a cyclone? i could build an enclosure on the outside of the wall with 3 hepa furnace filters and a box underneath to catch all the heavy stuff…

I suppose this could cause some wear on the impeller, which is aluminum, as it would be pulling all the debris through the blower as opposed to all the heavy particles being pulled down by the cyclone.

Anyone have opinions on this?


20 replies so far

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splintergroup

826 posts in 683 days


#1 posted 09-23-2015 09:19 PM

I have thought about directing the output air from my cyclone thorough the wall (no filter). The cyclone would catch the vast majority of the dust and chips and only the occasional stray flake would make it outside. Of course, this is greatly dependent upon where you live and how much you want to annoy your neighbors. My cyclone filter usually stays quite clean, but on the not so rare occasions I forget to dump the barrel, the filter gets a healthy coating of fine dust which really reduces the airflow. Eliminate that filter (and remember to empty the barrel), everything would be golden.

In your case I’m guessing two things. Either you don’t want to lose the space eaten up with the cyclone/filter in the garage, or you are considering just dumping the output from your blower directly to your filter box in the great outdoors (no cyclone).

The cyclone/filter outside would be good since you can regain the lost space and still collect/stop all the dust and chips. Of course you will be expelling a large volume of air from inside your garage which will require an open window and reheating/cooling of the fresh air introduced for replacement.

Skipping the cyclone seems to me would quickly saturate your filters and just make a mess.

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ChrisBarrett

99 posts in 519 days


#2 posted 09-23-2015 10:09 PM

The space isn’t too big of a deal, and I don’t care much about losing conditioned air because it’s not conditioned :-D I’m just wondering if my idea of building a “filter box” outside the garage that the DC empties into would even work. If I understand your reply you’re thinking that even those filters would fill up pretty quickly so I’d lose efficiency that way.

Really my goals are two fold: lower cost and keeping up the CFM of the collector.

edit regarding my neighbors, I don’t have any close enough that the random fine dust would bother – the noise might become annoying for them. The DC kind of drones, from the few times I’ve turned it on. I don’t know how much of that noise will be translated outside.

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joey502

487 posts in 979 days


#3 posted 09-23-2015 10:36 PM

If you add a cyclone then you do not need the filters or collection box outside. There will not be enough debris left after the cyclone to worry about collecting outside.

I added a super dust deputy to my dust collector over a year ago and have not yet needed to clean the filter.

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ChrisBarrett

99 posts in 519 days


#4 posted 09-23-2015 11:00 PM

Any ideas/numbers on how much a cyclone cuts down on efficiency and cfm?

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JeffP

573 posts in 853 days


#5 posted 09-23-2015 11:23 PM

I think if the exhaust is going to be outside a true “cyclone” is definitely overkill.

OTOH, a dirt-cheap separator is still a good idea to help you better coral the majority of the waste.

I made one last weekend out of a standard large metal trash can. Just cut a couple of 4” holes in the lid to insert a pvc elbow and a short straight pvc coupler. The elbow is positioned so as to spray the stuff coming in along the perimeter of the can, and then the exiting air comes out the center-mounted straight connector.

It works ridiculously well. Even gets the majority of the “fine but not invisible” dust. Good chance there is still a significant amount of too-small-to-be-seen dust at the exit, but I have no way to measure it.

Both my DC and its exhaust will be outside when I’m finished. Cheap, quiet, functional waste handling and dust reduction. The remainder of the dust remediation will be via a ceiling mounted air cleaner.

Anyway, my separator cost me all of $25 and a couple hours of work. Well worth it I think.

-- Last week I finally got my $*i# together. Unfortunately, it was in my shop, so I will probably never find it again.

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crank49

3980 posts in 2432 days


#6 posted 09-24-2015 12:45 AM



I think if the exhaust is going to be outside a true “cyclone” is definitely overkill.

OTOH, a dirt-cheap separator is still a good idea to help you better coral the majority of the waste.

I made one last weekend out of a standard large metal trash can. Just cut a couple of 4” holes in the lid to insert a pvc elbow and a short straight pvc coupler. The elbow is positioned so as to spray the stuff coming in along the perimeter of the can, and then the exiting air comes out the center-mounted straight connector.

It works ridiculously well. Even gets the majority of the “fine but not invisible” dust. Good chance there is still a significant amount of too-small-to-be-seen dust at the exit, but I have no way to measure it.

Both my DC and its exhaust will be outside when I m finished. Cheap, quiet, functional waste handling and dust reduction. The remainder of the dust remediation will be via a ceiling mounted air cleaner.

Anyway, my separator cost me all of $25 and a couple hours of work. Well worth it I think.

- JeffP


You made it as good as it needs to be.
This setup would only reduce the available static pressure about 1 1/2” to 2”.
A true, high efficiency cyclone could reduce your available pressure by 6” to 12” or more.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

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ChrisBarrett

99 posts in 519 days


#7 posted 09-24-2015 03:32 AM

Okay can someone explain to me the static pressure measurement? Is more static pressure good, bad?

View Fred Hargis's profile

Fred Hargis

3930 posts in 1954 days


#8 posted 09-24-2015 11:13 AM

SP is a measure of drag (resistance to air flow) on the system. As the number grows, so does the resistance.

-- Our village hasn't lost it's idiot, he was elected to congress.

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ChrisBarrett

99 posts in 519 days


#9 posted 09-24-2015 12:47 PM

So a Thien baffle, for example would add less static pressure than a cyclone but also allow more dust to go through? So you’d have a more efficient DC in terms of air flow but less efficient pre-filtration.

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Fred Hargis

3930 posts in 1954 days


#10 posted 09-24-2015 01:12 PM

I’m not sure what the difference is between the 2. Crank may have something, I’m sure there is a difference, but there are so many variables I’d think it would be a little hard to quantify.

-- Our village hasn't lost it's idiot, he was elected to congress.

View toddbeaulieu's profile

toddbeaulieu

780 posts in 2465 days


#11 posted 09-24-2015 01:15 PM

I ultimately plan to vent outside. My barn is heated in the winter so my plan for that is vent it back into the barn during the winter. For that I will need filters outside and a simple “window” for the filtered air to be forced back inside. For the summer I could eliminate the filters and close the window.

As for cyclone, I think it makes a lot of sense to shield the impeller from large debris. Sooner or later you’re going to have to deal with the pile outside and the cyclone helps with that, as well (bin).

Not smart enough to get into the scientific debate. A while back I read through all the Pentz material and simply got overwhelmed. When it comes time to upgrade my DC I hope to avoid getting hung up on splitting theoretical hairs. 3HP is a good amount of power and I question the value of stressing about these (assuming) minor factors. This is, of course, my own unscientific opinion. My crappy Reliant just barely meets my needs and I can only imagine what doubling the HP would give me.

View Bill7255's profile

Bill7255

354 posts in 1746 days


#12 posted 09-24-2015 01:56 PM

I will give my opinion based on my experience. Nothing scientific, just based on what I have done. Comparing a Thien baffle to a cyclone the Thien does very well, but falls short if you have a drum sander. A cyclone far exceeds the Thien in this area. I can’t really compare the loss as I have never run a back to back text to see what the effect is. I do believe going to a 6” main keeping the 4” drops as short as possible is significant. The other big factor is how well you collect the dust at the source. I am very happy with my setup. I went from a Thien baffle to a cyclone, and I am able to vent outside. It is a big plus not having to clean filters after using the drum sander. Here is a link to my setup.

http://lumberjocks.com/topics/117834

-- Bill R

View splintergroup's profile

splintergroup

826 posts in 683 days


#13 posted 09-24-2015 02:03 PM


Really my goals are two fold: lower cost and keeping up the CFM of the collector.

- ChrisBarrett

I wouldn’t worry then about a cyclone if you send the air outside. 3HP should move plenty of air, even for several wood chip producers running at the same time. Outside, you probably could get away with some form of a large box/bin around the vent to generally contain the dust, but beyond that any filtering would be overkill.

Inside, the cyclone helps keep the filter clean, which helps keep the airflow up.

View Shawn Masterson's profile

Shawn Masterson

1297 posts in 1409 days


#14 posted 09-24-2015 03:37 PM

this is my setup. You could make a barel like the first one on my setup. as to venting it outside, I see you are in WI so you don’t work out there in the winter?? because if you use wood heat then venting outside is never going to happen in the winter. you will back draft the stove and smoke out your shop.

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ChrisBarrett

99 posts in 519 days


#15 posted 09-24-2015 04:10 PM

I’ll work in the winter, but not a whole lot. I use infrared and a propane convection heater. Heating the air has proven to be ineffective so far, so I just heat me and whatever i’m working on.

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