How much dust do you see in your DC filters?

[Larry Fox]

I am in the (seemingly endless) process of installing a cyclone DC in my shop. I picked up a used 2hp Oenida blower unit and cyclone that had a giant plenum with 5 bag-type filters. I am replacing this with 2 Wynn cartridge filters which will give me about 600 sq/ft of filter area (as opposed to about 130 with the bags and less wasted space). I am placing the filters in an enclosure as I want to filter from the outside-in to make them easier to clean.

I had a “temporary” setup going where I had a long piece of 6” flex coming from the cyclone inlet directly to my table-saw so I could use the saw to make some cuts (some in ply, some in MDF). I had the plenum and the filter bags attached to the outlet side of the blower. I had a fiber bin attached to the bottom of the cone with a 2’ piece if 10” (I think) flex attached with some band clamps.

The blower is attached to the cyclone with an 8” rubber “plumbing boot”. Picture attached for reference on the install (shop doesn’t normally look as bad as it does in the pic). The plenum and filter bags are not attached in the picture.

Last night, in anticipation of installing my filter housing, I removed the filter bags and catch buckets and noticed that the filters and buckets had a surprising amount of dust in them. While it is good that they ended up being caught by the system, I am wondering if too much of the dust is making it to the filters and my concern is that my new filters will clog very quickly at this rate – and they were not cheap so I want them to last. This is my only exposure to “real” dust collection so I don’t really know what to expect.

My question, how much dust do others typically see making it to their filters? If the answer is “very little”, any idea why I am seeing so much? Could it be due to a leak somewhere?

Thanks in advance for your time.

Larry

dc_small.jpg

[Rod Sheridan]

Hi Larry, I have an Oneida cyclone with the external cartridge filter.

It has a dust pan at the bottom to catch the dust, which is inside the filter.

To clean the filter, you blow it with compressed air from the outside inwards, leave it for 10 minutes, and the dust has settled in the pan. Unclip the pan, empty it out.

No mess, no dust in the shop.

I don't understand how having the dust on the outside of the filter is better?

In answer to your other question, the pan is about 10 or 12 inches in diameter, and a few inches deep, it's normally about half full when I clean my filter, which is about every third or fourth barrel of chips.

Regards, Rod.

[Roy Wall]

Larry -

Same setup as Ron.....Oneida Super Gorilla 2hp.....and I get maybe a half inch deep pan of dust after (what seems like) at least 6-8 barrels of chips. I just use the small 35 gallon bin. I don't use a compressor; rather just tap the ribbing of the filter from top to bottom and let the dust inside filter down. I try and remember to take the filter out to the yard and clean once or twice a year too.

The connection to the bin is only about a foot long - I think this makes for a more efficient DC. I haven't cut a bunch of MDF either though.........as this would seem to be the worst of dust producers.

Oh, BTW - when I've cleaned the bin out, it will LIFT off the stand due to the suction when its fired back up again. Only when the chips build up enough will it sit flat and not lift. I was told by Oneida that is a sign of a good, sealed system.

[Larry Fox]

Hummm - I think I must have a leak somewhere which is not surprising given the temporary setup.

Rod, not saying it is better - it just seems easier given my setup.

[Chris Rosenberger]

Larry,
The amount of dust you get in the filters depends lot on the cfm of the filters you use. The more air that flows through the filters, the more fine dust that is going to get blown into the filters. The upside to using high cfm filters is that you will get better suction at the machines.

[Jamie Buxton]

I have a Woodsucker cyclone (2hp). I need to clean the filter about every ten or fifteen bins of chips. The bin holds 32 gallons.

[Jim Becker]

I generally only clean the filter on my Oneida setup about once per year and even then, there is almost nothing in it. The only exceptions have been when I, umm...overfilled the bin. But that's not the fault of the system....

[Greg Funk]

Larry,

It is quite possible that, given you have an older generation of Oneida, the cyclone is not as efficient at separating dust from the airstream as the more modern versions. I seem to recall Wood magazine conducting a test of cyclone dust collectors a few years back and there was a wide variation in the amount of dust that made it through the cyclone.

It might be worth a call to Oneida to see if there are any modifications you might be able to make that would improve the overall efficiency.

Greg

[Steve Roxberg]

Larry -

Oh, BTW - when I've cleaned the bin out, it will LIFT off the stand due to the suction when its fired back up again. Only when the chips build up enough will it sit flat and not lift. I was told by Oneida that is a sign of a good, sealed system.

It's good to hear that lifting the barrel is a good thing. My new install the Barrel lifts up and I was going to ask that question.

I also made sure that the first four feet of 7" pipe into my cyclone is a straight shot as recommended by Oneida.

[Jon Todd]

It seems like you would have to empty the barrel every 30 minutes.

[Jim Becker]

If there is anything outside of fines in the filter...you have a leak...probably at the connection to the barrel or with the barrel top.

[Mike Spanbauer]

I've run about 25 or so 50gal barrels through my Cyclone and I've accumulated no dust below my filter so far... not even enough to wipe on my finger.

However, realize that I've one of the largest units you can purchase and it SUCKS something fierce (upwards of 1650cfm / 13"sp.)

The dust collection at my tools is excellent, which is what I was driving for when I purchased this unit.

You might be able to add a neutral vane or perhaps a longer inlet (reducing the turbulence as the air enters the cyclone, which in turn will force more to cyclone down into the catch barrel vs. being blown into the filters)

g'luck and congrats on the new Cyclone!

mike

[Roy Wall]

It's good to hear that lifting the barrel is a good thing. My new install the Barrel lifts up and I was going to ask that question.

I also made sure that the first four feet of 7" pipe into my cyclone is a straight shot as recommended by Oneida.

Steve -

Yes -- 4 ft minimum I believe.......I'm able to go 10' straight with the 7" dia. pipe before it hits a 7"-6" reducer.

[J.R. Rutter]

Dust in the filter depends on a few different things:
velocity in the cyclone - higher = less dust in the filter
type of dust created - a sander makes lots of fine dust, saws etc. don't
leaks (as mentioned) - can pull dust from cyclone to filters

I liked the cartridge filters until I started running a 2-head sander with mineral dense hardwoods. Then I started blowing them up because no amount of compressed air cleaning would "unbind" the tiny pores...