Cyclone filter - a better way???

[Ken Krawford]

I just spent 90 mins. with 2 compressors and a shop vac blowing out the filter cartridge from my cyclone and even then I didn't feel that it was very clean.
Is there any way to employ some sort of disposable pre-filter and spare the cartridge so much dust?
Does anyone else have a different method of dealing with this problem?
Thanks for your insight.

[Mark Beiting]

Ken,
This might not help much, but here's what I do. I don't have close neighbors, so when the breeze is blowing in the right direction I take the filter "out back", hook up the hose from my leaf vacuum to the filter, and while that is running I blow the filter thoroughly with my back pack blower. It takes about 5-10 minutes and makes a nice dust cloud, but the filters feel like they are 5 or 6 pounds lighter after. The frequency on cleaning is directly proportional to the amount of time that my drum sander is being used. That thing produces lots of fine, filter clogging dust!

Cheers,
Mark

[ian maybury]

Hi Ken. I can't resist asking which cyclone you have, and what sort of work you mostly do. Although all cyclones will pass some very fine dust, and power sanders tend to produce a lot of it. Do you have a single or a double cartridge set up?

I guess one way of making the cleaning of cartridges a bit easier may be to install them in a cabinet so that the airflow is in the originally intended outside to inside direction. Cleaning is still going to be a bit messy, but somewhat easier. The down side is that it takes up more space, and that since the cabinet is under positive pressure it's very important that it doesn't leak - or it will let dust escape. You can add a coarse over sock in that situation to prevent coarser chips getting caught in the filter, but it won't stop fine dust..

Somebody may have experience, but i've not hear of using a pre-filter per se. It's got to be fine enough tos top the dust, in which case it'll need cleaning or throwing out too. Something like a bag might be an option, but the trouble is that again it has to be very fine to stop the dust, may be rather large if it's to have enough area, and will likewise be a PIA to clean.

The secret to a good long filter life (apart from minimising the dust they see) is also to ensure there's plenty of filter area….

[Roy Harding]

I finally gave up trying to keep the filter clean, and now vent directly outside. This may not be an option for you if you live in the city and have neighbours close by.

I used to clean the filter with my air compressor - but as others have noted that's not necessarily a good option. I have a drum sander which is used a LOT, so clogging of the filter was a major pain. At one point, I thought of putting a second cyclone between the current one and the filter, the idea being to let even more particles drop out of the stream before hitting the filter - but I never got around to trying it, and I'm not sure how well it would work. As far as a "pre-filter" goes, I also contemplated putting some pantyhose, or something similar into the exhaust stream prior to it hitting the filter, but gave that idea up as such a "pre-filter" would clog up even faster than the regular filter.

In short - I don't have the precise answer you're looking for, but if at all possible, I'd encourage you to think about venting outside (I haven't experienced any catastrophic heat loss since doing this - some, to be sure, but not enough to worry me, and I live in northern Canada. My dust collector is on often, for 5 - 30 minutes at a time, but does not run all day).

[Peter Aeschliman]

I finally gave up trying to keep the filter clean, and now vent directly outside. This may not be an option for you if you live in the city and have neighbours close by.

I used to clean the filter with my air compressor - but as others have noted that's not necessarily a good option. I have a drum sander which is used a LOT, so clogging of the filter was a major pain. At one point, I thought of putting a second cyclone between the current one and the filter, the idea being to let even more particles drop out of the stream before hitting the filter - but I never got around to trying it, and I'm not sure how well it would work. As far as a "pre-filter" goes, I also contemplated putting some pantyhose, or something similar into the exhaust stream prior to it hitting the filter, but gave that idea up as such a "pre-filter" would clog up even faster than the regular filter.

In short - I don't have the precise answer you're looking for, but if at all possible, I'd encourage you to think about venting outside (I haven't experienced any catastrophic heat loss since doing this - some, to be sure, but not enough to worry me, and I live in northern Canada. My dust collector is on often, for 5 - 30 minutes at a time, but does not run all day).


I agree with Roy. Even the best cyclones will pass the super fine dust and clog filters. A pre-filter is also a filter, so it will also clog eventually.

If you can't vent outside, the best you can do is find a way to increase the time between cleanings and reconfigure your setup so that the cleaning process itself is easier.

To increase the time between cleanings, it's probably a simple matter of increasing your filter surface area via bigger or more filters.

To make cleaning easier, you could do something like Ian proposed, or change your technique (the leaf blower for example).

But ultimately, the simplest solution is to vent outside.

[Ken Krawford]

Thanks everyone for taking the time to respond. This was one of those posts where is suspected that there was no "free lunch" but secretly hoped that someone had developed an ingenious way to solve my problem.
Venting outside is totally out of the question. I think from now on I'll set reminders to clean the filter more frequently. I do have a decent leaf blower. Next time I'll give that a try.

[Ken Krawford]

Ian, I have a cyclone based on the Bill Pentz design that I purchased as a kit many years ago and a single cartridge filter. I have all the typical stationary tools found in most shops but suspect that my Performax 16-32 is the culprit with the fine dust reaching the filter.


Hi Ken. I can't resist asking which cyclone you have, and what sort of work you mostly do. Although all cyclones will pass some very fine dust, and power sanders tend to produce a lot of it. Do you have a single or a double cartridge set up?

I guess one way of making the cleaning of cartridges a bit easier may be to install them in a cabinet so that the airflow is in the originally intended outside to inside direction. Cleaning is still going to be a bit messy, but somewhat easier. The down side is that it takes up more space, and that since the cabinet is under positive pressure it's very important that it doesn't leak - or it will let dust escape. You can add a coarse over sock in that situation to prevent coarser chips getting caught in the filter, but it won't stop fine dust..

Somebody may have experience, but i've not hear of using a pre-filter per se. It's got to be fine enough tos top the dust, in which case it'll need cleaning or throwing out too. Something like a bag might be an option, but the trouble is that again it has to be very fine to stop the dust, may be rather large if it's to have enough area, and will likewise be a PIA to clean.

The secret to a good long filter life (apart from minimising the dust they see) is also to ensure there's plenty of filter area….

[Steve Peterson]

All I can think of is a spare filter so you can swap them while you vacuum the dirty filter. Even if you assume a 90% effective cyclone, only 10% of the fine dust will transfer back to the new filter.

Steve

[ian maybury]

Ta Ken. The Pentz cyclone is normally pretty good, but they all pass some fine dust.

As before a dual filter cartridge set up would take a lot of the heat off i suspect - running a single cartridge with a drum sander doesn't sound ideal. (not enough filter area)

The other point is that exhausting outside (even if only for short periods while running the sander) may be less of an issue than you think if you keep the cyclone in line. In that the dust going outside should be fine to invisible, and in fairly small quantities.

I have my Pentz style system set up so that i can do this, but haven't yet tested it as i unthinkingly fitted an 8in aluminium blast gate on the fork in my fan exhaust (one leg goes outside, one to the filters) and the thing leaked dust like a sieve into the shop. (the gates fit very poorly on that type) So i had to temporarily seal it up with silicone pending a change to a proper sealed diverter valve.

Maybe somebody like Roy or Peter already venting outside can comment on how much dust they see outside?

[Peter Aeschliman]

I have a 16/32 drum sander and an ebay cyclone with a 3 hp grizzly motor and impeller. I'll bet my cyclone isn't nearly as efficient at separation as Ken's Pentz design. I can't see any dust outside at all. Surely there is dust blowing out of the shop, but I don't really see any traces of it.

[Roy Harding]

I don't see much dust at all with the naked eye. However, it's definitely there - the cement and siding near the exhaust is discoloured, and in the winter the snow in that area is noticeably dirty.

[William C Rogers]

I have the eBay cyclone with a 3hp Jet 1900 DC (14" impeller). I had just recently set it up venting outside. I ran my Supermax 19-38 for about 6 hours making 7 cutting boards. Very little dust outside. Here is the second drum that has one 8' board run through the jointer on the bottom with the rest being from the drum sander.
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Here is what I saw outside. The exhaust is right near my trailer fender. I ran my finger on the fender to give an idea of how much was there.

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The eBay cyclone does a darn good job.

[Martin Wasner]

How about a bag house with an auto shaker?

[Chris Parks]

Make sure you have no air leaks in and around the collection bin and its connection to the cyclone.

[Ken Krawford]

My problem with exhausting outside is that my cyclone sits in the corner of a poured concrete basement and the top of it is right at ground level. I'm not about to cut a 6" hole through the band of my house. We live in cluster homes and my neighbor is only 20 ft away.

[Mike Hollingsworth]

My first answer was to have an extra filter to get back to work quickly. Better answer was to vent outside. If anyone in So Cal can use an extra just let me know, it's yours.
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[Chris Parks]

My problem with exhausting outside is that my cyclone sits in the corner of a poured concrete basement and the top of it is right at ground level. I'm not about to cut a 6" hole through the band of my house. We live in cluster homes and my neighbor is only 20 ft away.

You could duct the exhaust to a better exit point if that helps. I have seen exhaust ducting exit the building and go vertical to get it above the building line and this also dissipates some noise as well.

[ian maybury]

Chris' point about making sure the drum is well sealed and the cyclone working properly is important. Don't know how often it happens, and it seems unlikely - but too much CFM seemingly may also overdrive a cyclone so that it doesn't separate fines as well as it could.

It makes sense too that placing an exhaust where it spreads whatever dust it puts out over a larger area, and ideally into moving air (prevailing wind direction?) must greatly reduce any visible consequence...

[Rick Potter]

I don't get it. What is the difference between venting a small amount at a time outside, or cleaning your filter with a leaf blower outside all at once? Speaking in generalities here, I realize Kens situation with the neighbors is pretty tight, but since others mentioned they do the same thing...

My outside vent blows directly at a block wall about 8 feet away, and I see nothing on it.

Mike, I gave mine away also.

[Steve Peterson]

I don't get it. What is the difference between venting a small amount at a time outside, or cleaning your filter with a leaf blower outside all at once? Speaking in generalities here, I realize Kens situation with the neighbors is pretty tight, but since others mentioned they do the same thing...

My outside vent blows directly at a block wall about 8 feet away, and I see nothing on it.

Mike, I gave mine away also.

You are absolutely correct Rick. There is no difference in the amount of dust released into the air. The only difference is the perception of the neighbors.

Steve

[Bernie May]

Let's not forget that you have to make up that air you blow outside, which is not ideal when there is a large temperature difference inside versus outside.

[Charles R Johnson]

Fine dust from my drum sander clogged up my final filter on an Oneida 3 hp Gorilla in short order. After replacing the final filter with Wynn filters which greatly improved the operation because of the added filter surface area, I installed prefiltration right at the drum sander. It consists of a 35 gal trash can and a modified Wood Crafters separator with two shop vac filters in series inside . The dust is captured at the source and never makes it to the main DC. I can forward some pictures if interested.
Ducting outside is not an option for winter operation in a colder climate. The DC actually does a pretty good job of heating the shop when operating. Thankfully I live in a cooler climate and therefore don't need to direct it outside in the summer.

[Roy Harding]

Let's not forget that you have to make up that air you blow outside, which is not ideal when there is a large temperature difference inside versus outside.
That's what I thought too, until I tried it.

As I said in my original reply, I live in northern Canada (I can drive into Alaska in about 4 hours) and the heat loss I experience, while noticeable, is not enough to concern me. I originally thought I'd vent outside in the summer, and live with having to constantly clean my filter during the winter. And yet, when winter came, I found that I could continue to just vent outside.

I don't run my dust collector all day, but continuous usage of 1 - 3 hours on any given day is not unusual, and cumulative usage of short duration (say 5 minutes) over any given day can be over 4 hours (all of the preceeding usage estimations, of course, are dependant upon what I'm doing that day).

[Roy Harding]

Fine dust from my drum sander clogged up my final filter on an Oneida 3 hp Gorilla in short order. After replacing the final filter with Wynn filters which greatly improved the operation because of the added filter surface area, I installed prefiltration right at the drum sander. It consists of a 35 gal trash can and a modified Wood Crafters separator with two shop vac filters in series inside . The dust is captured at the source and never makes it to the main DC. I can forward some pictures if interested.
Ducting outside is not an option for winter operation in a colder climate. The DC actually does a pretty good job of heating the shop when operating. Thankfully I live in a cooler climate and therefore don't need to direct it outside in the summer.
That is ingenious - I'll keep it in mind should outside venting become problematic for any reason (the main culprit in my system is also my drum sander.)

[Chris Parks]

I don't live in a cold climate but one important detail gets lost in the venting outside debate and that is the heat or cold stored in the building itself. When the air temperature is held at the required level the building then absorbs heat or cold from the air and when air is replaced by running a dust extractor the air is quickly brought back to the required temperature by the heat held in the structure of the building. I forget where I read about it but it is a very significant factor in heat loss or gain in the air temperature. As for venting outside the dust fall out is insignificant and can be further dissipated by running the exhaust vertically above the building line or elsewhere if required.

[ian maybury]

Guess it makes a difference whether you are of the run the dust collector all the time to keep the air clear, or of the switch it off once each operation is finished schools. It'd also make a big difference what sort of work you do - i'm for example usually (but not always) in the spend ages getting set up and then take only minutes to make the cut scenario… High volume repetitive stuff might well result in a very different story....

[Roy Harding]

Guess it makes a difference whether you are of the run the dust collector all the time to keep the air clear, or of the switch it off once each operation is finished schools. It'd also make a big difference what sort of work you do - i'm for example usually (but not always) in the spend ages getting set up and then take only minutes to make the cut scenario… High volume repetitive stuff might well result in a very different story....

You're right - my dust collector has a remote control fob which is fastened to my shop apron. I do all the set up, and then push the button on the fob as I reach for the machine's on button - and the reverse when finished. I don't run it all the time - I have air cleaners which keep the air clear.

[Allan Speers]

Ken,

I just remembered a "crazy" idea I once had about cutting down the dust from a filter-less, outside-vented cyclone system.
It may not work, and in moist cases it's not necessary as can be seen from many posts in this thread, but FWIW:

I thought about adding a "water filter" on the outside. Basically, just a bucket of water. The DC's output would first get channelled to a number of smaller tubes, then those tubes would be inserted into a bucket full of water.

That's pretty much it. The dust would collect in the water, as the air bubbled out. Every once in while you'd just dump the bucket in the back yard. Maybe a safety valve could be rigged so that if the water got too thick with dust, back pressure would open the valve and everything would go out into the air. Also, you'd need a way to keep the bucket full of water, and mosquitos out.

Heck, you could probably even do this indoors, if you have a slop sink, or a way to pump the bucket outside.

It probably would work, and could solve the "really close neighbor" problem.

[Mike Chalmers]

Ken,

I just remembered a "crazy" idea I once had about cutting down the dust from a filter-less, outside-vented cyclone system.
It may not work, and in moist cases it's not necessary as can be seen from many posts in this thread, but FWIW:

I thought about adding a "water filter" on the outside. Basically, just a bucket of water. The DC's output would first get channelled to a number of smaller tubes, then those tubes would be inserted into a bucket full of water.

That's pretty much it. The dust would collect in the water, as the air bubbled out. Every once in while you'd just dump the bucket in the back yard. Maybe a safety valve could be rigged so that if the water got too thick with dust, back pressure would open the valve and everything would go out into the air. Also, you'd need a way to keep the bucket full of water, and mosquitos out.

Heck, you could probably even do this indoors, if you have a slop sink, or a way to pump the bucket outside.

It probably would work, and could solve the "really close neighbor" problem.
I believe that this would kill your CFM. I do not think dust collectors have the power to overcome the pressure a column of water would exert.

[Allan Speers]

I believe that this would kill your CFM. I do not think dust collectors have the power to overcome the pressure a column of water would exert.

Not if all the tubes only get inserted a few inches. The silt would then settle to the bottom.

Well, maybe. It's certainly worth a try, if the "neighbor" situation is that bad.

[Kevin Jenness]

My impression is that cartridge filters are not that well suited to quantities of fine dust. If outdoor venting is not an option and space is available, tube or bag filters of sufficient area are easier to clean by occasional whacking on the outside.

[Wade Lippman]

That's what I thought too, until I tried it.

As I said in my original reply, I live in northern Canada (I can drive into Alaska in about 4 hours) and the heat loss I experience, while noticeable, is not enough to concern me. I originally thought I'd vent outside in the summer, and live with having to constantly clean my filter during the winter. And yet, when winter came, I found that I could continue to just vent outside.

I don't run my dust collector all day, but continuous usage of 1 - 3 hours on any given day is not unusual, and cumulative usage of short duration (say 5 minutes) over any given day can be over 4 hours (all of the preceeding usage estimations, of course, are dependant upon what I'm doing that day).

It would be fun to have a HVAC type calculate what it would cost to run a 2000cfm DC for an hour with a 70 degree difference. I suspect it is not trivial, but don't really know.

OP... I think you are making too much out of this. Unless your situation is really marginal, a little dust in your filter won't hurt anything.

[Wade Lippman]

Not if all the tubes only get inserted a few inches. The silt would then settle to the bottom.


Unless you took care to really mix the air into the water, the air bubbling out would take most of the dust with it. And if you did really mix them, the air flow would go to nothing.

I wonder if you could run the exhaust to a second cyclone.
I have a Dyson canister vacuum on a Dust Deputy. I can fill the can with ROS dust and nothing gets through to the Dyson filters; about 95% is captured by the Dust Deputy and all the other 5% by the Dyson cyclone.

Mind you, I am happy with how my Grizzly 3hp cyclone works out of the box.