Re-build

[RCOX]

I hope these pictures come through.

Thought I had a new idea for a tophat but after looking through older posts, I find the sandwich idea already done. Sorry, had no plans on stealing someones idea. It turned out ok. Seems to work well except I have a little more bypass. May need to play with the outlet a little. Removed all but one of the sharp 90 degree ells. Have an idea to eliminate it also.Will have to give it a try, later. Let me know what you think.

[retired2]

Raymond,

You don't need to apologize for using someone else's idea.  That's what this forum is about - sharing ideas and techniques.  Steal shamelessly!

Your long radius ell's should help a lot, too bad the one that remains is right at the fan inlet.  It would be good if you can figure out a way to eliminate that one.  And of course longer term, you should replace the 4" pipe with 6".

Here's something to keep in mind if your are tight on space.  Long radius ell's follow the law of diminishing returns.  Anything over 2xD provides only a small additional benefit, and after 2.5xD the line goes almost flat, i.e. no benefit. 

I did not count how many ells you pieced together, but I find it easier to just buy 1.75xD ell's from Oneida Air.  They are 24 gage, 5 segment, and fully adjustable.  Also, I silicone caulk the joints rather than tape them.  It makes a cleaner looking installation.  The cost of a 6" ell is $15.79.  Of course, shipping is an issue, but I finally accepted the fact that I was going to use quite a few of these and I just ordered enough parts to get to $200.  At that level shipping is free.

[RCOX]

Retired2: That "U" took 6 ells. I had to buy 2 more than I had on hand. At Lowes they are $4.98 each for 6".  I think I can move the "U" towards the front of the separator and put 3 ells together for a 90 and put about 18" of straight pipe to the dc from there. This will eliminate the last sharp 90. I will continue to change out to 6" pipe as money allows. It takes 3 ells to make a 90 the way I have done it for a cost of $14.94. Lowes is only 4 miles from my house. This may look funny but is a lot cheaper than Oneida, Pennstate etc for basically the same results, plus I don't have to wait for it to get here when I want to make a quick change. This does seem to have more suction than my original design but I seem to have a little more bypass than I did with the original Thein Baffle setup. I am thinking it may have to do with the outlet pipe. Will have to play with that and see.

[retired2]

This does seem to have more suction than my original design but I seem to have a little more bypass than I did with the original Thein Baffle setup. I am thinking it may have to do with the outlet pipe. Will have to play with that and see.

Raymond,

I'm not sure how your new separator differs from your previous one, but for sure the outlet pipe position is one thing you should experiment with.  However, the diameter of the separation chamber may also be an issue, especially since you have 6" pipes.

I am building a 5" separator, and I reluctantly decided to use a 33 gal Brute garbage can simply so that I could build the separator to a larger diameter.  Phil expressed concern that a 20 gallon can and the resulting smaller diameter might cause some by-pass problems with my 5" pipes.  Just for comparison, the 33 gal Brute results in a separator I.D. of 19-5/8", while the smaller 20 gal can would only provide for a 16-7/8" I.D. separator.

Another thing that may be contributing to the bypass problem is low air velocity.  You currently have a 4" system until just upstream of the separator, then you increase to 6".  For a given load condition, the air velocity in the 4" pipe will drop by half when it hits the 6" pipe, and of course the separator works best with higher velocities.  As you continue to replace 4" pipe with 6" this should increase the velocity in the separator and improve its performance.  To test this possibility, open both of your 4" headers while feeding sawdust to the system.

[RCOX]

The "old" design was a side inlet/standard baffle setup on a 30 gallon brute plastic trash can. The "new" design is a tophat on a 30 gallon metal trash can which is  20" i.d.

I have tried opening another line as you suggest and yes it does increase velocity in the separator BUT it decreases (by +/- 1/2) the suction on either line. My point being, you may/may not get better separation but you definitely lose suction at the tool where you are working. In my opinion, this has the possibility for dust/chips to fall out of the airstream and build up in the duct. I just need to continue to replace the 4" with 6" as money allows.

In regards to the bypass, I may have stumbled on my problem. I was jamming the duct into a bucket of chips to see how the system sucked them up. It did a great job of picking up fine dust and chips but because I was jamming the system the separator didn't have realistic time to do it's job. When I was running my table saw and a drum sander today the system worked great. Letting it do it's job instead of forcing it to do more than it was designed for made a drastic change.

I am also looking for a local distributor for some 1.5Xd ells as suggested. For the record, I have used 26 gauge duct and if I turn on the dc without having a gate open it WILL collapse the duct as long as 1 gate is open all is ok. I know I have a larger dc than most people on here have described but I just have to remember to have a gate open, so I always leave the 1 on the tablesaw open as a reminder.

Tahnks,

Raymond

[retired2]

I am also looking for a local distributor for some 1.5Xd ells as suggested. For the record, I have used 26 gauge duct and if I turn on the dc without having a gate open it WILL collapse the duct as long as 1 gate is open all is ok. I know I have a larger dc than most people on here have described but I just have to remember to have a gate open, so I always leave the 1 on the tablesaw open as a reminder.

Tahnks,

Raymond

I know some dust collectors can collapse 30 gauge pipe, but I've never heard of anyone collapsing 26 gauge. 

One of the reason's I never puchased my fittings at Lowe's is because the store closest to me only carried the 30 gauge.  Home Depot sometimes had both.     

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The Lowes I go to carries both.

My dc definitely will collapse the 26 gauge in a long run, the fittings and short runs seem to hold up well. I have a 10' run that I noticed about half flat before I opened a gate. That is with a 2" open pipe on the same line (it doesn't have a gate on it, kind of a safety) it goes to my overblade hood. Don't remember if the picture I posted show it or not. The new 6" main line to my tablesaw and drum sander only goes 10' for now. I put a wye for the 4" to the saw and drum sander and the other leg goes to the 2". I placed the seam on top and taped it as I recall reading was proper.

Any feedback or ideas on my thoughts as to the possible cause for bypass? Overloading the system, maybe?

Thanks,

Raymond