A Hybrid Dust Collector Bag?

[Jeffrey Makiel]

Emptying the bottom bag of my 2hp single stage dust collector is a hassle at best. I'd like to use a plastic bag for the lower filter bag, but it will reduce my filtration area too much. Another option is install a cannister filter to increase filter area, but I've heard too much about clogging. So I was thinking...

I wonder if 4" tube filters will give me the best of both worlds: a non-clogging quality felt bag, and more filter area. Oneida once sold these filters, but I also believe that they can be made-to-order. Here is a comparison of standard filter bags and 4" tube filters.
20" dia x 33" high bag= 16.6 sqft
20" dia x 38" high bag= 18.7 sqft
4" tubes (qty=13)= 37.4 sqft

Using the tube filters, I would double my filter area thus allowing me to use a plastic bag. The only catch is finding somebody to make the tube filters. The rest is easy work as shown below.

Has anyone else done something like this? Any thoughts?

-Jeff

http://i3.photobucket.com/albums/y84/Beff2/1.jpg

http://i3.photobucket.com/albums/y84/Beff2/3.jpg

http://i3.photobucket.com/albums/y84/Beff2/DustCollector2.jpg

http://i3.photobucket.com/albums/y84/Beff2/DuctCollectorModexploded.jpg

[Julio Navarro]

Why not make a base that will hold both the filter unit and the blower unit?

You have them seperated and attached only by the outtake duct from the blower, not sure that is the best connection.


Would it not be easier and less expensive to manufacture paper bag liners that fit inside the drum and can be easily tied and disposed?

Your design looks like it would allow for a bag type of liner to be inserted into the cannister no unlike a vacuum bag.

You may also be able to use two 20" DIA bags in tandem. Using your disign as it is you have enough room for two large bags by shortning the outtake duct from the blower.

I am not sure what the effects on CFM restrictions multi filters would have.

[Jim Becker]

...And there is always American Fabric Filter for a larger, free flowing, low-micron filter bag for the top... ;)

[James Biddle]

Another vote for AFF. They'll custom make a larger bag to fit your space.

[Jeffrey Makiel]

I requested a quote from American Fabric Filter as recommended above. They can make simple open ended tubes (not like the ones shown above) for about $10 each. I think I'm going to try to give it a shot.
thanks...Jeff

[Bruce Page]

Jeff, what software are you using for those excellent models?
Pro-e? Solidworks?

[Jeffrey Makiel]

Bruce...AutoCAD, plain vanilla.
-Jeff

[Ken Belisle]

Jeff,

When I wanted to go to the plastic bottom bags on my 1 1/2 HP DC, the folks at Penn State told me that I had to also upgrade to the canister filter for greater filter area. Since doing it, I have had no problems with clogging at all. Only a weekender, so I can't speak for those that run their DC's all day, all week, but I've had less problems with clogged filters since going to the cannister, than I had with the 2 bags.

Just my opinion.........

[Per Swenson]

Hello Jeff,

I remember your arm for the tablesaw and that was elegant.

This project reflects the same attention to detail.

Very impressive.

However the JDS cannister has a cleaning arm attached to a

integral paddle which negates the clogging problem inherent in

this set up. We manufacture a lot of sawdust.


Don't let me stop you from building a alternatve,

That's great fun also, me I'd rather make saw dust.

Per

[Jeffrey Makiel]

Ken,
This seems to be a dilemma that I can not decode. I'm a weekend woodworker also. But I hear a lot of complaints about clogging of cannister filters, and the need to frequently knock them to unclear clogs between the pleats. Then there is the need for occassional blow down which my neighbors probably won't appreciate.

I don't own a drum sander, nor do I work much with MDF board. So massive amounts of fine dust should not be an issue. But I still read a lot of complaints when searching this forum, and other forums, about clogging with all sizes of dust particles.

I don't have a problem with the job that my quality bags do. The upper bag releases the dust cake automatically, and the performance remains pretty consistent. It's when I'm emptying the collector that becomes big hassle.
-Jeff :)

[Bart Leetch]

"I don't have a problem with the job that my quality bags do. The upper bag releases the dust cake automatically, and the performance remains pretty consistent. It's when I'm emptying the collector that becomes big hassle.
-Jeff "

I think you may have answered your own question. Just make the emptying easier & less of a mess.

Actually I think your idea does make more surface area but having the air channel its self into each tube getting from point A to point B maybe counter productive.

[Jeffrey Makiel]

Bart,
You read my mind. With my existing upper bag, the pressure gradiant across the bag's surface is probably more uniform than using 13 individual tube filters. Although the tube filters will double the surface area of the upper bag, I'm not sure if there will be an overall performance drop from the swirling air that will now be forced to make a sharp turn into each tube. Usually these tube arrangements are used in linear flow bag houses.

I'm beginning to lean towards Per's comment on using a canister filter. A cyclone is out of the question for me.
Jeff :)

[Bob Dodge]

Jeff,

Beautiful job on your drawing, and excellant design on the filter-stage by the way. The tube-filter approach is far more compact than over-sized filter-bags, and is an approach I've heartily recommended in the past.

While tube filters are a rarity on consumer-model dc's, they've been around for a long time on industrial systems. I'd contact an industrial dc manufacturer, or filter vendor.

You can add even more filter-tubes, if you use a slighly over-sized square plenum, mounted to the top of your dc.

Nice job, good luck.

Bob


http://www.belfab.net/jNBM-OP.html

[tod evans]

jeffery, although not exactly compact i`ve done kinda what you`re talking about and it works well..02 tod

41734

[Jeremy Gibson]

Jeffrey,

I have a similar DC from Harbor Freight. I've added a Wynn canister top and plastic bag bottom. I must admit that I'm still running duct so I haven't used it yet.

My question is to the orientation of the blower outlet and the filter inlet in your drawing. On my unit, if I elevate and rotate the motor as you have drawn the outlet and inlet are on opposite sides of the unit. So the hose from blower to filter would make a 45 degree turn, run at an angle, and make another 45 degree turn. Does your unit have the input on the side illustrated? I think I would have to offset the two pieces to get the hose to run straight.

[Jeffrey Makiel]

Jeremy,
I think I understand what you are saying. Your fan discharch is a mirror opposite and you need to add 45 degree elbows as shown below...
http://i3.photobucket.com/albums/y84/Beff2/45degree800x640.jpg
Although this is not optimum, it will still allow you to have a nice straight duct into the inlet side of your fan. As far as the outlet side, the double 45 degree elbows will be a small compromise.

When I use to design commercial and military HVAC systems for a living, we always avoided abrupt elbows before and after the fan. Elbows at these locations wreak havoc on fan performance more than just the loss due to the elbow. It's like having a kink in your aortic artery!

Perhaps rotating the fan 45 degrees one way, and rotate the bagtree 45 degrees the other way as shown below...

http://i3.photobucket.com/albums/y84/Beff2/temp2800x640.jpg

[Jeremy Gibson]

That's exactly what I had pictured as I stood in my garage corner and mentally moved things around. I even thought of just twisting the bag tree on a rectangular platform and adding a 45 degree angle to the motor mount stand. It would make the overall footprint a little larger but keep both halves together on one rolling platform.

I think for now I'll mount the motor to the wall and live with a bend to the bag tree. Do you think there is any minimum distance to keep between the discharge port and the bag tree? With both rotated 45 degrees I could theoretically get them inches appart.

[Allan Johanson]

If you're going to that effort then you may as well take it a step further. As long as you have the motor amp draw overhead to spare.

Toss that flex hose going from the blower to the filter housing and replace it with metal like what some friends and I did. We wanted to get rid of the 5" flex hose from the blower to the filter housing to boost airflow. The performance increase was amazing. From 860 cfm (before) to 1180cfm (after) through 10' of 6" pipe.

*** Warning: before doing any mods to a DC that results in less resistance, you should check the amp draw with an ammeter to make sure you aren't going to make your motor sad by drawing too much current.

I'll see about making a new thread for this when I have more time. In the meantime, here's a pic:

http://i41.photobucket.com/albums/e254/allansouthsurrey/shop/dcbacktogether.jpg

Cheers,

Allan

P.S. Jeff, I think you may be losing some of the benefit of going to all that filter area by having all those little pathways for the air to try and go up. Too much turbulence, methinks. I haven't tested a thing like this except for splitting the airflow before the fan in a cyclone. That test wasn't positive. Slight decrease in airflow and a 17% increase in amp draw.