My cyclone dust control system clogged up. Why?

Frank Pellow

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Location
Toronto, Ontario, CANADA
Earlier this week, I was preparing a lot of rough lumber with a jointer and planer. Usually after a couple of hours of this, I need to empty the 35 gallon barrel beneath the cyclone (an Oneida 2hp Commercial). So I checked and, to my surprise, the barrel had not reached the ¾ full mark. It turns out that I should have checked more completely because, if I had, I would have observed that the barrel was almost empty.

After about another hour, the pick up on the jointer stopped working:

Dust control jamb 01 -no pickup on jointer -small.JPG

My first thought was that there was a jamb somewhere in the jointer or the drop to same. There wasn’t and I was confused.

I finally got around to really checking the barrel and found this:

Dust control jamb 02 -almost empty barrel -small.JPG

Now, I was really confused.

Next, I took the elbow off the end of the main pipe coming out of the dust control unit. There were chips sitting within the pipe:

Dust control jamb 03 -chips remaining in pipe -small.JPG

OK this stuff must be gathering somewhere and I am running out of places to check. How do things look in the funnel about the barrel? Here is photo looking up into the mouth of the funnel:

Dust control jamb 04 -chips inside funnel above the barrel -small.JPG

The funnel was completely filled and the material was really jammed in. I thought that probably a piece of larger material had been sucked up and wedged in somewhere thus causing the problem. But, there was no such thing. I stuck a broom handle up into the funnel loosening the material and getting it to fall down and I found no large pieces of anything. I still have no idea what caused the material to gather in the funnel rather than dropping into the barrel. :huh: :doh: :confused:

Also, there was about a barrel full of material in the funnel, but I was pretty sure that I had generated more chips and dust than that. Where was the rest?

I took the tray off the bottom of the filter and found this:

Dust control jamb 05 -chips in bottom of filter tray -small.JPG

And, in the filter, I found this:

Dust control jamb 06 -chips clogged in filter -small.JPG Dust control jamb 07-another photo of the clogged filter -small.JPG

The filter was completely filled and, if anything, it was jammed tighter than it was in the funnel.

Here is (a small) part of the mess on the floor that I created in emptying the filter and the funnel:

Dust control jamb 08 -the mess on the floor as I unclogged things -small.JPG

Once the chips were out of the filter, cleaning out the rest was quite a chore. I don’t have a compressed air machine and I expect that would have made the job easier. What I ended up doing was banging the end on the floor about 10 times, vacuum up the residue, bang it another 10 times, vacuum up the residue, etc. etc. etc. Stuff kept falling out. The following picture shows the result of 10 thumps after having already thumped the filter about 500 times:

Dust control jamb 09 -filter still depositing dust on floor after more than 500 bangs -small.JPG

After about 1,000 thumps stuff stopped falling out and I cleaned out the interior with a vacuum. I guess that I am going to have to break down one of these days and purchase a compressor.

To wrap this up, here is a photo of the totally disrupted shop part way through the investigation and clean up:

Dust control jamb 10 -view of the centre of the shop during clean up -small.JPG

By the time I completely cleaned up everything, I had gathered 2 and half barrels of chips and sawdust.

I am happy to report that, once I put everything back in place, things worked well and, in about an hour of woodworking, I have already filled the barrel to the ¾ point.

I am very interested in hearing theories about how the system got clogged up in the first place. It remains a total mystery to me.

The trouble shooting part of my manual is no help. I plan write to Oneida soon and ask if they have any ideas about what may have happened.
 
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Any chance that the temp and humidity in the air in your shop was at or near dewpoint levels and the sawdust just glued itself to the inside of the filter system after it passed thru' the venturi that the cyclone creates? That compression/decompression of the air thru' the cylone could possibly cause a serious lowering of temperature and cause the moisture in the sawdust to condense and stick to the insides of the unit?
 
I also posted a similar thread on the Canadian Woodworking forum and just received a very plausible suggestion there from someone who goes by the handle "Maintenance". That person said:
Well Frank, from what I have, recently read ( I have no experience with this), when the barrel becomes too full, the blower begins to draw chips out of the barrel. Then the filter becomes totally clogged, then the airflow is insufficient to work at all, and the dust just packs in. It sounds like what I read is true. Hope that explains it.​
I think that this could very well be it.

I have now written both to Oneida and to Welbeck Sawmill (where I bought the system) describing the situation. Let's hope that they clear up the msytery soon. By the way, I could find nothing like thsi described on the Oneida web site.
 
Steve's on to something. Most likely an air leak in the barrel,lid and or the hose leading down will cause an updraft in the cyclone. After that the chips have nowhere to go but out the impeller and in to the filter. Or a clogged filter will cause this also. I feel for you It's a mess, especially the filter. The Oneida unit I had before did the same thing. Another reason I like my clearvue. (you can see the the chips moving down into the bin):thumb:
 
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Air leak in the barrel?

That would certainly be my First guess.

And for FRANK, I don't know about that "high dollar" Vac you have,:rolleyes: :D , but on most shop type vacs, you can take the vacuum hose and plug it into the outlet side, and that would give you plenty air to blow out your filter pretty good, especially if you lightly tap on the filter as you blow on it. That is how I always clean my vacuum's filter.
 
Any chance that the temp and humidity in the air in your shop was at or near dewpoint levels and the sawdust just glued itself to the inside of the filter system after it passed thru' the venturi that the cyclone creates? That compression/decompression of the air thru' the cylone could possibly cause a serious lowering of temperature and cause the moisture in the sawdust to condense and stick to the insides of the unit?
Good theory, but I doubt it very much in my case. The shop is relatively dry and I never let the temperature get below 10 degrees (I think that's about 50 farenheit).
 
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..And for FRANK, I don't know about that "high dollar" Vac you have,:rolleyes: :D , but on most shop type vacs, you can take the vacuum hose and plug it into the outlet side, and that would give you plenty air to blow out your filter pretty good, especially if you lightly tap on the filter as you blow on it. That is how I always clean my vacuum's filter.
I did think of that but my "high dollar" Vac (as you put it) does not seem to have any such output connection.

posted later: OK, I checked again and I found the ooutflow opening hidden away down near the floor. The "air blast" produced is not bad and I will test it tomorrow and see how it does blowing upon the pleats in the filter.
 
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I doubt there is a leak anywhere

For all you folks suggesting an air leak, I am almost certain that this is not the case. This evidenced by the fact that, when the barrel is near empty, there is so much suction in the system that the barrel gets pulled of the ground. Also, after cleanup, everything works OK again and I suspect that it would not if there were a leak somewhere.
 
After you had said that you had check the fittings and the drum. I would have to say the filter was clogging up slowing down the air moving in the cyclone. That has been My personal opinion of the problem with the Onieda design. The blower doesn't move enough air to allow the cyclone to do it's job. Thus more dust ends up in the the filters. MAKE THIS PERFECTLY CLEAR. I'M NOT WANTING TO START A CYCLONE WAR HERE. Just stating my personal experience with there product.
 
... when the barrel becomes too full, the blower begins to draw chips out of the barrel. Then the filter becomes totally clogged, then the airflow is insufficient to work at all, and the dust just packs in. It sounds like what I read is true. Hope that explains it.​


It's happened to me twice, both times when I wasn't paying attention... I do my best to monitor barrel level, but when you're on a roll planing, sometimes it just gets away from you, and the jointer or planer will fill it quick. The one time, the cylone & filter were both completely jammed... What a mess. I think you can get sensors that will warn you when the barrel is near full.
 
... when the barrel becomes too full, the blower begins to draw chips out of the barrel. Then the filter becomes totally clogged, then the airflow is insufficient to work at all, and the dust just packs in. It sounds like what I read is true. Hope that explains it.​


It's happened to me twice, both times when I wasn't paying attention... I do my best to monitor barrel level, but when you're on a roll planing, sometimes it just gets away from you, and the jointer or planer will fill it quick. The one time, the cylone & filter were both completely jammed... What a mess. I think you can get sensors that will warn you when the barrel is near full.
Sam, thanks for confirming that this is the likely cause. As well as the person that was quoted above, another person has told me that it happened to them. So, you are now the second person who has told me that it experienced the problem. So, this appears to be a common situation.

I wish that Oneida would put something about it under 'trouble shooting' in their manual and say something about it on their web site. Better still, their barrels should come with sensors.
 
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OK, here's my theory...:rolleyes:

Once (or maybe twice:rolleyes: ) I filled the barrel up to the top and dust started accumulating in the filter. I cleaned out the filter.

Once I filled the barrel almost to the top, and didn't clean the filter till I thought about it the next day, and sure enough, it had some dust in it.

Could be that the filter got clogged and decreased the airflow sufficiently to throw the cycle out of whack.:dunno:

I think I'll go check my filter:D .
 
Steve Kraus of Welbeck Sawmill called me early this morning (great service -thanks Steve :) ). He had already talked to someone at Oneida and their theory about what happened is the same as one that ‘Bryan @ Woodstock’ on the Canadian Woodworking forum had posted yesterday.

Bryan said: "What I am thinking is, that the barrel was full, and the cone blocked, you replaced the barrel and proceeded to use the DC. All the chips then will go to the filter causing the mess you have now. I know cause I have done it a few times. If the barrel is right full I have to reach up in and clean out the cone."
 
Yes, a couple of times.

Then I would submit this is the source of the problem as it just happened to me too. If the bin backs up, you have to make sure the cyclone is clear too. I know have a 2'-3' piece of one by two sitting next to the cyclone. If it clogs up, I will stick it up the cyclone after the drum has been removed to loosen any clog just like I did to clean it this time.

That said, I am going to have a go at that photo-electric solution as well although I have to get a mag switch for the cyclone too as it currently just uses a 220 'light' switch. :rolleyes:
 
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