I have a cyclone DC (Oneida Gorilla) and am looking for opinions for the best air flow to minimize the amount of very fine dust getting to the filter. In other words, which air flow would minimize the need to clean the filter?
If I open up all the gates in the shop to give maximum air flow, I would get the best cyclonic effect and centrifugal force but fine dust doesn’t have much mass and the increased airflow to the filter could suck more of the fine dust from the spinning material in the cyclone. On the other hand, having just the gate open to the fine dust producing tool would decrease the air flow to the filter but cause more turbulence in the cyclone which could result in more fine dust going to the filter. I’ve tried various combinations but I still have to clean the filter more than I would like when I am doing a lot of resawing with a bandsaw. If I had a drum sander, I am sure I would be facing the same issue.
Replies
have you checked out : http://www.clearvuecyclones.com/Bullentin/index.php
Problem with that site is, of course, that it's limited to one product.
I just figured that the cyclone concept is pretty much the same regardless of who makes it. Therefore any performance issuse would be similar. Just thought it would be another resource for info.
I don't own a cyclone myself, I have a Phil Thien design cyclone seperator lid on a 55 gallon drum. It works great but the fines still get to the DC filter. I'm pretty sure thats just physics at work.
I found the tech support people at Oneida to be very helpful. Have you tried calling them for specific suggestions?
Contacting Oneida was too obvious for me to think of it. Great suggestion. If they have a good answer I will post it.
That is a question for Oneida. They engineered the cyclone so should have that information readily available. From what I have heard they a re quite good at assisting with trouble shooting. You can also check the discussion forums at Oneida.
You should have minimal carry over to the discharge filter.
Bill Pentz has some information you might find useful. In particular, there is a static calculator which might hi lite some inefficiencies in your piping configuration.
http://billpentz.com/woodworking/cyclone/index.cfm
But first go to Oneida. The main benefit to a properly designed cyclone is have almost all of the dust going to the trash bin, not to the exhaust filters.
Don
I discussed the situation with the Oneida technical support. They felt there really wasn't much that could be done and it wouldn't matter much if I had maximum or minimum air flow. Very fine dust just doesn't have enough mass to completely make its way to the bin. Some of it gets sucked out of the cyclone to the filter. They explained that over time, more and more of the very fine dust will get trapped by the filter. Trying to clean the filter by by blowing compressed air on the outside will only be partially successful because the filter material is so dense that not enough air gets through to dislodge the finest of the fine dust. Periodically I need to hose the filter inside and out.
I have an airflow guage and with a clean filter, it sits just above 0. They say to not let it go above 3. At first it takes many weeks to get to 3. If I then clean the filter with compressed air, it only drops down to about 1. Eventually the time it takes to get back to 3 gets shorter and shorter as the filter holds more and more very fine dust. It is then time to hose it out. I did that this week and am back to just above 0 again.
I've looked at the Bill Pentz material in the past and looked at the ClearVue material recently but will take another look at Bill Pentz since he is sort of the DC guru.
Penn State Industries has a filter cleaning option which seems to pass the air flow out the bottom of the filter, thereby loosening the dust from the inside. I am not sure where the dust ultimately goes. Does anybody have any experience with this option? I may make an alternate pan for the bottom of the Oneida filter with a blast gate. I could attach flex tubing to that gate and route it out the window and turn on the DC to blow out the dust from the inside. As you can surmise, I hate cleaning DC filters!
Doesn't sound like a great situation Tom.
Maybe this is why Mr. Pentz went to the lengths he did to develop his design and to make it public domain.
This design is used by Clear Vue and they and Mr Pentz may have a business relationship.
To save any questions, I have no commercial affiliation with either Mr. Pentz or Clear Vue other than I sent Mr Pentz a small donation a few years ago and I do own a Clear Vue cyclone which is still in the box.
I would suggest you place you situation on the Clear Vue forum (don't say you have an Oneida) to see what those users experience. I seem to recall reports of teaspoons of dust being remove from the filter clean-out after considerable use. This is one reason I purchased their unit, and a friend of mine who built his own based on the Pentz design.
Bill says:"A good cyclone design will remove over 99% of all wood dust and chips by weight before they get to the filters."
If you are getting a significant carry over to the filters, then I would challenge the usefulness of the machine. If you are stuck with it, you might consider adding a baffled knockout drum between the cyclone and the filters. It will reduce the efficiency slightly, but a lot of the carry over will collect here.
By the way, you aren't overflowing your waste bin on a regular basis are you? If the debris cannot exit through the bottom of the cyclone, it has no where to go but through the blower and into the exhaust filters.Don
I considered ClearVue before I bought the Oneida. I think its design is superior because it directs the airflow downward as it enters the cyclone. I have considered retrofitting a spiral baffle into the Oneida like the Clear Vue has. With something to direct the airflow past the pipe that goes to the filter, it just seems that less of the fine dust would go to the filter. I will post the question there to compare experiences.
I didn't get the ClearVue for a few reasons; it was too tall for my location, I really didn't like the plastic materials, and I would rather be woodworking than building a DC. But those Clear Vue users sure are proud of their DC's!
I think the Oneida easily gets more than 99% of the dust before it gets to the filters. When I blow out the filter, I only get teaspoons of powder-like dust. The problem is that 1% that goes to the filters really impacts airflow and blowing the filters is very ineffective at getting the it out. With my tools, the only one that causes problems is heavy use of the band saw, especially when I am cutting lots of veneer. If I am not using it much then I can go months without cleaning the filters in any way. If I am using it a lot, then it will more like a week before I need to clean the filters. Like I said, the cleaning interval gets shorter and shorter as the filter slowly clogs. Considering that the Oneida was an upgrade from a Jet single stage DC, this is like heaven. With the Jet, I would have to clean the filter more than once a day when cutting veneer. I guess I am a malcontent.
I must admit I once overflowed the bin but that was big chips from a surface planer. I'll never do that again. That was my first experience with hosing out the filter.
For now, I will continue experimenting with open blast gates combinations looking for the best airflow. If I ever discover anything of significance, I will open a new thread.
Hello, Tom -- Just to compare notes with your experience, I've had a 1.5 HP Oneida for about 12 years and have been fairly happy with it, although I'd like to upgrade to the external filter type one day. My shop is air conditioned (I live near Orlando) and having good DC is really necessary. Most of the machines in the shop are ducted to the cyclone, but I also use a trash-can separator for the planer and jointer which is connected to the Oneida to catch the high volume of chips they create instead of filling up the 50-gallon cyclone drum. I've cleaned the filter several times by removing the dust from the pleats first, then blowing the remaining dust from the inside out. While I don't have a way to measure the passthrough, I'm convinced from a practical point of view that the filter continues to be adequately functional after cleaning it this way. I also have a new filter as a backup if needed (the one for the 1.5 HP model is on sale right now). Since I work with exotics a fair amount, it isn't too hard to look around at horizontal surfaces to see how much fine dust isn't being captured, especially with something like redheart or padauk. So far it's doing OK and I don't exhaust to the outside. The much larger external filter would seem to be a significant upgrade, but my cyclone is installed in a dedicated closet without enough room to make the switch. Just thought you might want to her my experience . . . . Jim
Jim, thanks for the info. I'm not sure which Oneida systems do not have external filters since all the current systems seem to have them. Their portable systems have the filter above the cyclone, rather than to the side, so maybe that is like yours. Otherwise, our situation is similar.
Like yours, my shop is heated and cooled due to living in Austin, TX. I would love to vent the system directly outside and forget about the filter but I have to pay a lot of money to condition the air and don't want to bring in unconditioned air to replace what I blow outside.
I have blown off my filter from the inside too. It is much better than just blowing it from the outside but still doesn't do as good of a job as a hose. It is also quite messy if the wind shifts at the wrong time. :-)
With the airflow gauge sold by Oneida, they warn to not let the reading get beyond 3 without cleaning the filter. They also caution that the airflow after cleaning will not be as good as a new filter. With a new filter, the gauge was just above 0 and I get close to that number after hosing the filter. The initial cleanings with air will return the airflow gauge to 1. The longer the time since hosing the filter, the higher the number after blowing the filter. Eventually it only drops to 2. At that point I hose it out again and get back to near 0. I think the filter does such a good job of trapping the very fine dust that it makes it difficult to dislodge it with air. Having two filters so I can switch to a dry one while the other dries is probably a good idea but so far I have been able to do without. If you can hose your filter, you might try it to see if you can notice a difference in airflow.
...tom
My Oneida cyclone is one of the first designs which came out with 1.5 HP and has the filter mounted inside and at the top of the cyclone cone, which makes it a bear to access. It's a permanent mount, not a portable, with permanent ducting mostly designed by Oneida. I wasn't aware of the airflow gauge offered by the company. I'll check it out. Are you saying you hose out the filter with water? Mine look like they're pleated paper filters. Maybe it isn't paper?
From your description and pictures, that doesn't look like a lot of fun. The airflow gauge might not work for you since the sensor sits in the duct between the blower and filter. My filter looks like paper but is washable with water. In fact the filter on my shop vac looks the same and is also washable. Since your filter is older, it might not be washable but it might be worth asking Oneida. If it isn't, maybe they have one that is. Periodic washing really helps my situation.
...tom
Thanks. Since I have a new spare, I'll try it out.
I am soooo spoiled. I also have the Oneida 1 1/2 HP unit, but I live in the country and my closest neighbor is miles away and my shop is several hundred feet from my house. I ducted my collection system through the wall and removed the filter. Not only did this increase the air flow but I don't get any dust exhausted inside my shop. I really haven't noticed that much heat loss in the winter either.
OK, just don't rub it in.
I live in Seattle.If I duct my dust collector outside, it would blast right into my neighbor's dining room.I'm pretty sure that would annoy them.He's just another Windows guy, but she's a lawyer, so I probably better not.
I really wish I could do that. It might work in the winter because the temperature will quickly jump 4 degrees in the shop when I have the DC and a couple other tools turned on. It is the summer that is the problem here in Austin, especially this summer. We are already over 50 days with 100+ degrees for the year, vs. a normal 11 days. I would be sucking out 80 degree air and replacing it with 100 degree air that my tools would try to heat to 104. You are really lucky!
So where do you live and what winter temperatures do you have. Seriously, I need to install a dust collector and would like to know if I should consider ducting the exhaust directly outside. We rarely have temperatures below zero Fahrenheit. My nearest neighbor is about a thousand feet away and I doubt if he would notice the difference.
A cyclone works like a centrifuge so that the big bits easily make it to the periphery and, conversely, the fine dust doesn't.Any dust handling system MUST end in filters, usually bags, to catch the fine stuff. You're probably on a hiding to nothing on this issue. If there were a solution it would be widely adopted.You might find that there is an optimum airflow to catch the most fines in the cyclone. You want the fastest possible rotation without turbulence. You could play with your gate openings and see if slowing down the flow gives you better results as long as chips don't settle out in the ducts.Please note that I do not have a cyclone but am speaking from a general standpoint. In my production days it cost me 4 man hours a week to clean out the wretched bags - usually on overtime rates. It cost a lot more NOT to do it :-(
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