Dust Collection - How much might this change help?

[Glen Blanchard]

I have a 3 hp Oneida dust collector that has served me very well for seven years with no signs of trouble. I'm not really having difficulty with dust collection, but realize that I am violating one of the rules of dust collection - don't put an elbow within 6' (give or take) of the dust collector. I have violated that rule of thumb, and am wondering what kind of impact corrective surgery might have. I realize there are lots of variables here but am hoping to get the opinion of others who have greater knowledge than I in this area.

The image below shows what I have now. On the other side of that wall is my Oneida cyclone (in a closet with the air compressor). You can see that I have placed an elbow within the first 12" or so of the dust collector with another elbow another 5' away. I have the vertical headroom in the closet to raise the dust collector enough to eliminate both elbows and provide a straight run before the first 'Y', although due to the weight, it will be a sizable hassle.

I am hoping someone with some knowledge and/or experience might be able to comment on the performance improvement such an alteration might provide. I am not really expecting a quantitative response. I would be happy with hearing if this change would provide a noticeable improvement or if I am likely not to notice any improvement at all.

Thanks in advance.

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[Jim Becker]

Straight run benefits include less turbulence in addition to not having the "loss" caused by the two 90º elbows like you do now. You're also shortening your duct work by a few feet for further improvement of performance. It might not be a huge difference, but it would improve performance to some extent, even if it's not noticeable in a big way. Raising up the cyclone also gives you more headroom for the bin...which might mean either a larger single bin or even a double if space allows and that increases the time intervals between dumping the bin.

[Andy Giddings]

+1 on Jim's comments. I think the only way you're going to find out if it's worth the change or not is to try it out. You can run the Excel calc from Bill Pentz's web site to see what the theoretical difference is in pressure drop with different duct configurations. Having said that, it sounds as if you are happy with your DC so if it ain't broke ....?

[Hoang N Nguyen]

I'm no expert but I've had my DC set up both ways and noticed a slight difference between the 2.

I have a 3hp V3000 DC and I have a straight 5' run from the DC inlet before making a 45* turn where it runs for another 5' before entering the first wye fitting. At the old shop where space was limited, I had a 90* elbow directly on the DC inlet, straight up a few feet into another 90* from there it runs a few feet and slips into wyes.

I had great pick up with both setup but I do notice my jointer is pulling a bit more air with the new duct runs. Part of it may be due to the fact it's closer to the DC (in terms of duct run not distance of tool), the other part may be due to how I have less turns. Before, it went through (3) 90* elbows and some flex pipe, now it's just a wye and a 45* elbow and some flex pipe.

From what I've gathered with my own experience and from what research I've done. Dust pick up doesn't change so much but separation is the bigger concern. Like Jim mentioned, the turbulence will effect on how well your cyclone separates the dust.

[Larry Frank]

While theoretically, it might make a difference. I do not believe that you could find a measurable difference. The only way to know is to get some very accurate measurement devices..hot wire anemometer(?).

I do not think the change is worth the effort. But if you have lots of extra time, it might be scientifically interesting

[Glen Blanchard]

While I do have plenty of time (I'm retired) I would rather be standing at the lathe. The lack of overwhelming responses claiming that I am drastically limiting my DC system has helped me decide to leave things as they are.

Thanks all for the posts.