Dust collection pipe size change at inlet - Woodworking Talk

rmonzo · 12-19-2008, 08:34 PM

I just bought a new 2hp dust collector. It has one 5" inlet or two 4" inlets.
I'd like to run 6" lines to the machines and reduce the 6" to 5" at the inlet to the impeller housing.
Has anyone had any experience doing this and are there potential problems in doing so?
Thanks.

**Leo G** · 12-19-2008, 08:56 PM

Yes there will be problems. You will reduce the air velocity in the 6" pipe and in doing so you may get settling out problems and clogs in your pipe line. Your best bet is to use 5" in the trunk and 4" for your feeds to your machines.

rmonzo · 12-20-2008, 09:06 AM

Leo,
Would you also suggest that the drops be 5'' before a short 4" connecting to the machine?
Thanks,

**Leo G** · 12-20-2008, 10:37 AM

No, you want the air speed in the drops to be faster than the air speed in the trunk. Most of the time the drops are vertical and you are lifting the dust/chips which means you are going against gravity. Your DC might be to small to have all your machines connected at once and a whole DC network laid out. Make sure you use as much smoothed wall tubing (not flex tubing) in your system as possible. Flex tubing at the final last few feet to the pickup port at your machine.

daryl in nanoose · 12-20-2008, 11:09 AM

Just a little addition to Leo's post if I may, stay away from 90's as mush as you can and use 2 45's and a short piece of staight pipe instead and the longer the staight pipe is coming into the dc the better it will perform.