Here's my new conversion of a small dust collector.(//)
I'd be curious to hear how it performs. The small separator diameter has the potential to create waste by-pass. Also, I don't see an outlet pipe extending down into the separation chamber. That feature is part of all the builds I've seen. I'm not sure how this might effect performance.
The outlet pipe extends into the chamber according to Phil's rule of 1/2 the 4" pipe diameter.
Seems to work fine on test, but the real test will be my thicknesser.
Quote from: chrism3 on December 28, 2017, 03:44:11 PM
The outlet pipe extends into the chamber according to Phil's rule of 1/2 the 4" pipe diameter.
Seems to work fine on test, but the real test will be my thicknesser.
Sorry, I couldn't see the outlet pipe due to the glare on the plexiglass. You might be surprised at the performance with your thickness planer. The chips tend to be a little heavier and the centrifugal force keeps then to the outside wall where the separation occurs.
Fair comment, here's a better shot.(//)
Quote from: chrism3 on December 28, 2017, 03:44:11 PM
The outlet pipe extends into the chamber according to Phil's rule of 1/2 the 4" pipe diameter.
Seems to work fine on test, but the real test will be my thicknesser.
Planer shavings usually don't even make a full revolution around the tophat in my system. Fine dust is the hard stuff to separate, it can make a couple trips around the chamber.
Well I've given my collector a real workout over a couple of days, and it didn't pass!.
I was using my planer on macrocarpa (cypress), which doesn'r present as particularly difficult timber. The chips were narrow, light and a bit over 1 inch long, and clumped together like a lot of straw. They clogged the top hat fairly quickly, refusing to drop down the baffle slot, with the result that most passed into the lower bag of the collector. This happened even though I was only taking a small cut each pass.
looking at your picture of the outlet pipe. it looks like you have a piece of particle board (or mdf) under the Masonite drop slot piece. the masonite should be beveled on the bottom side and sand the edges really smooth and round off the back edge of the slot where it stops and i would get rid of that piece of particle board (or mdf) or really cut it back from the edge of the masonite. i think if you had a larger drum you'd be better off.
"dabullseye" offered you some good advice about the baffle plate, it should be thin and smooth. However, I would not waste your time fixing the baffle without increasing the chamber diameter.
In your second photo I can look into the inlet pipe and see quite a bit of the outlet pipe. That should not be. The diameter of the separator should be large enough so that the inlet pipe is well outside the diameter of the outlet. If not, you will have a lot of waste by-pass.
Thanks to both of you for your comments. I'll have a rethink. The masonite is in fact bevelled underneath, and the bevel continues onto the mdf base. But I could remove the mdf around the baffle edge as you suggest.
Here's a pic of the chips that did make it into the barrel -they are up to 3 inches long, not 1 inch as I previously stated.
(//)
For whatever it is worth, the only time I plugged my separator was when I was planing cypress. However, mine was very wet, water running ahead of the planer feed rollers. Shavings were six inches long. I wrote a post about the experience and the mess. But my situation was so extreme I don't think it would be wise to pin your problems on cypress. When I plane dry cypress there are no problems.
Quote from: retired2 on February 26, 2018, 08:19:21 PM
...... However, I would not waste your time fixing the baffle without increasing the chamber diameter.
In your second photo I can look into the inlet pipe and see quite a bit of the outlet pipe. That should not be. The diameter of the separator should be large enough so that the inlet pipe is well outside the diameter of the outlet. If not, you will have a lot of waste by-pass.
With less effort you could try a transition from round to rectangular inlet and in that way get the inlet outside the diameter of the outlet. That may also have effect on separation on coarse chips due to better "air rotation".
That is if you don't want to increase chamber diameter which I agree is the best solution....
The white fitting that you can see is a transition from round to rectangular .
I can see that, sorry...
I meant a much more narrower "slot" compared to that one. Of course you can't decrease the area too much but it seems that the area of the rectangular part of your intake is almost larger than the circular part?
OK, thanks. I'll see if I can make a narrower slot.
In addition to the comments above I would look at a different transition piece. Your current transition piece looks more like an adapter in that it mates a round fitting with a square fitting and has no real transition between the two. I would look at the transition fitting on Retired2's build (link below) as an example. Since you have a small diameter you will want to move as much of the flow to the outer wall of the separator as possible to keep it away from the outlet pipe. I would consider a transition piece with the rectangle being the height of your separator with a width that would have an area equal to the round inlet area. Good luck.
http://www.jpthien.com/smf/index.php?topic=563.msg3024#msg3024
Thanks. Looks like I am in for a re-build. We live to learn.
I've mostly fixed the problem. I had left a sharp edge on the end of the slot, and once a piece of cypress got caught on it other pieces would build up on it. It now works beautifully - only gets stuck when I send a heavier than normal (cypress) load to it.
I recently commented in this thread and another about how I plugged my separator with wet cypress. The most recent comment was when someone expressed concern about a threaded rod used to support the baffle being a source of potential birds nests. My response described exactly what you are experience. When a plug occurs, it usually starts at the end of the drop slot and then rapidly backs up until the entire slot closes off entirely
So, you are exactly correct, the end of a drop slot should be very smooth well rounded and no knife edges.
I have been reading posts on this site for the last couple of days and don't see anywhere that anyone has looked into the orientation of the inlet in relation to the DC inlet. This design as well as retired2's show the inlet on the right side. That would seem to match the rotation of the DC impeller. There are many examples of the inlet to the separator on the left. Am I making something out of nothing?
Quote from: psilun on May 15, 2018, 05:01:51 PM
I have been reading posts on this site for the last couple of days and don't see anywhere that anyone has looked into the orientation of the inlet in relation to the DC inlet. This design as well as retired2's show the inlet on the right side. That would seem to match the rotation of the DC impeller. There are many examples of the inlet to the separator on the left. Am I making something out of nothing?
This subject has been discussed countless times. I have posted Cincinnati Fans information on air rotation and the effect on blower performance several times. Use the search function and you will find what you need.
Quote from: retired2 on May 16, 2018, 03:03:57 PM
Quote from: psilun on May 15, 2018, 05:01:51 PM
I have been reading posts on this site for the last couple of days and don't see anywhere that anyone has looked into the orientation of the inlet in relation to the DC inlet. This design as well as retired2's show the inlet on the right side. That would seem to match the rotation of the DC impeller. There are many examples of the inlet to the separator on the left. Am I making something out of nothing?
This subject has been discussed countless times. I have posted Cincinnati Fans information on air rotation and the effect on blower performance several times. Use the search function and you will find what you need.
The search function has seemed a little off the past couple days. Or my memory of what terms were used in threads I wanted to go back to.
psilun you should check out this thread: http://www.jpthien.com/smf/index.php?topic=550
Short answer is any air rotation going into the impeller is a negative effect on performance. A longer straight pipe between the chamber and the impeller or a straightener is the best way to deal with those losses.
This link took about a minute to find. Search for "rotation" and filter results to "Retired2" posts.
http://www.jpthien.com/smf/index.php?topic=828.0
I"m sure if you repeat the process using other words or phrases you will find more threads because in the thread above it is clear from my comments that I had previously discussed the subject.
As stated, pre-rotation of air in either direction produces undesired results. Rotation opposing the vane rotation increases the hp power requirements, while rotation in the same direction as the vane rotation lowers the CFM's produced.
Glad you posted that as I now see what I was doing wrong with my searches. The quick search in the upper right corner must only show recent results. If I search "rotation" there I get 5 results, 4 of them are this thread. If I use the advanced search I get many results.
Quote from: RobHannon on May 17, 2018, 07:58:32 AM
Glad you posted that as I now see what I was doing wrong with my searches. The quick search in the upper right corner must only show recent results. If I search "rotation" there I get 5 results, 4 of them are this thread. If I use the advanced search I get many results.
Good point. The simple search is so prominent I suspect others may be using it exclusively as well. I stopped using it so long ago so I forgot its limitations. Ironically, the advanced search function is far less conspicuous, but far more useful.