Help Fine Tuning

[JoeGuitar]

Hi,

I built one of these collectors a couple of weeks ago.  It's connected to a steel city 1.5hp dc.  Previously had a lid from Lee Vally for the trash can that did hardly anything.  I upgraded th dust bag on the top of the collector to a filter from Wynn & wanted to keep as much dust and dubris out of the filter & bag.

I find that this does a great job of keeping the bigger stuff out but when I hook it up to my drum sander, the fine sawdust finds it's way past the trash can & into the bag/filter area.

So I was wondering if anyone can give me any pointers on making it a bit more efficient.

Here's some pics so you can see how my seperator is currently set up.


Lid on the trash can.


Bottom with reference to the inlet.  Also shows the 3/8" grove that the trash can lip fits into - no air leaks.


Side view showing the outlet port.


Showing the inlet & bottom of the separator with respect to the edge of the trash can.

[phil (admin)]

Looks like you've got the mechanics right.

A couple of things to consider:

(1) Leaks around the rim will greatly reduce separation.  At least for testing, I'd use some masking tape between the top and the can.  I'd also tape the seams of the can from the outside.

(2) Sanding dust is tough.  Even large cyclones struggle w/ sanding dust.

[Joes Username]

If you find there is leakage around the rim of the can, another suggestion would be to put a bead of non-harding silicone in the groove of the lid and thin it out to around 1/16 - 3/32 thick and let it dry. Did that to a lid i just made and it worked great.

Also maybe use the handles of the trash can and some bungy cables to really secure the lid to the rim, kind of like this:
http://www.jpthien.com/smf/index.php?topic=383.0

_

[JoeGuitar]

Hi everyone - thanks for the input!

The can was already sealed with silicon & I held a smoke around the lid with the dc turned on & no leaks.  I did put a strip of 3/8" weather strip into the dado for the can - just in case it ever decided to leak.

Guess I'll live with the dust in the bag until I spring for a clearvue.

Phil - thanks for putting this out on the net for us  to build.  It's a nice affordable solution to get good separation.

Joe

[Vodkaman]

Just a thought, though I may be way off base. The inlet pipe is angled slightly down onto the baffle plate. This may cause the airstream to deflect upwards, from which the lighter particles might not recover and make it to the exhaust vent. Something to think about.

Dave

[phil (admin)]

Just a thought, though I may be way off base. The inlet pipe is angled slightly down onto the baffle plate. This may cause the airstream to deflect upwards, from which the lighter particles might not recover and make it to the exhaust vent. Something to think about.

Dave

Good catch, I missed that.  The incoming dust needs to be parallel to the baffle/lid for optimum results.  You do not want it bouncing off either the baffle or top.

[JoeGuitar]

Thanks Dave.

I'll redo the inlet port & see how that goes.

Joe

[bruegf]

The other thing I noticed that's different from mine is that you have the inlet positioned more or less center on the major diameter of the baffle whereas I have my inlet positioned right at the start of the major diameter.   So far, I see no larger sawdust and very, very little of the fine dust getting past the separator into my dust collector.

Fred

[JoeGuitar]

Hi Fred,

So what you're saying is that I should have the 120 degree portion of the baffle starting at the rear of the inlet port as shown in this picture.




Ok,  one more thing.  Should there be any space below the inlet port and the baffle?  I don't see any in this pic but some of the builds I've seen here do have a space............



Joe

[phil (admin)]

No Joe, you've got that part of the alignment right.

[bruegf]

I started the 120 degree part of the baffle an inch or two before the inlet, i.e. the air flow coming from the inlet sweeps over almost all of the 120 degree part of the baffle.   Don't know it that's how its supposed to be, but its what I did and I get virtually no dust, coarse or fine, into the plastic bag of my harbor freight dust collector (maybe a cup or two for every 10 gallons of dust in the separator), and rarely need to blow out the canister filter.   I made my separator as a side inlet, don't know if that alters the tuning at all either.

Fred

[phil (admin)]

I started the 120 degree part of the baffle an inch or two before the inlet, i.e. the air flow coming from the inlet sweeps over almost all of the 120 degree part of the baffle...I made my separator as a side inlet, don't know if that alters the tuning at all either.

Fred

The side inlet does help separation rates because the dust has been heading straight before it is directed into a spin.

As far as where to place the inlet pipe over the larger radius, what we're trying to avoid is a siphoning effect where the incoming airstream couples with air under the baffle, which will grab already separated dust and start it revolving again.  There is always going to be some siphoning, but the closer to the edge of the larger radius, the more you'll get.

[bruegf]

Interesting, so you're saying I'd be better off locating the major diameter more centered over the inlet?   I'll have to try that before starting the next big project.   Haven't tried any other location - worked so well as I first set it up that I haven't played with it all yet.

Thx

Fred

[phil (admin)]

I'd say about 1/3 onto the larger radius is a pretty decent rule.

[bruegf]

Thanks Phil,

I'll give that a try.

Fred