dust collection advice please.

[justinpeer]

Having just picked up a used 2hp dust collector, I now need to pipe it up. I want to keep it just outside the workshop to keep the noise down and save space inside so need to run pipe to the various machines. It's not a large workshop but it's a bit awkward to run pipe as there's benches along the walls and the roof is too low to run it along the tops of the walls.

I know that smooth pipe is preferable for efficiency but that would mean running 100mm drain pipe and fitting that with the various joints/fittings would be more awkward than running flexible pipe. The dust collector has a 125mm intake so the choice is either to run smooth 100mm pipe or 125mm flexible pipe. I could then just sleeve down to short lengths of 100mm flexi at the machines.

Does anyone know how much less efficient 125mm Flexi pipe would be than 100mm smooth pipe?

Photos of the shop. You can see the gutter downpipe dust collection I currently have running from the shop vac and cyclone, which isn't very efficient because of all the joints and diversions. I could replace it with larger pipe and just bring the feed in under the floor by the lathe but can't get any further than that under the floor.

 

[Inspector]

Here is a calculator you can play with. http://www.63alfred.com/freecalc/ductloss.htm

It will let you play with the duct size, length, elbows, etc. Then you can repeat the calculations with flex hose to compare the two. You'll have to convert to imperial as it hasn't got provisions for metric units. If you chose to mix the smooth and flex together you'll need to calculate each part separately and add them together to get the losses.

The flow numbers provided for DC's in the brochures or the data plate is with the motor and impeller only with extra to look better than a competitor. Add the filtration etc and realistically cut it in half for what it will do in the shop. Ducts, hoses, add on cyclone/separator lids if installed, flow losses through a machine come off it.

Flex hose can have up to three times the flow losses compared to smooth ducting. Best is to keep flex hose to a minimum.

With the DC outside you can get away with minimal filtration if any and that will improve the flow some.

Pete