2" Old Plenum and Slide Valves	New 4 valve plenum
2" Plenum & Valves

Originally I used commercial 2" blast gates but, due to the solid slider, they were constantly getting packed with sawdust so they didn't close completely, thus leaking.   This was a maintenace problem and general headache!

Some time ago I built a plenum and updraft valves for my 4" DC.   I recently I tried the same thing for my 2" DC but, after time, fine dust built up on the flappers until they wouldn't seat correctly and I lost vacuum pressure at my tools.
  I decided to try slide valves and a 2" PVC plenum, mounted to the ceiling just as the earlier plenum had been.  
Originally, I had 3 tool positions that needed 2" vacuum, the router table, West (above workbench), and the 10" bandsaw / oscillating sander.
More recently (2018) I moved the workbench to the small East bay which required a 4th 2" port in the East bay.   I also converted the router table to a roll around table with 4" vacuum port (which works way better than the 2"), leaving one slide valve unused.    

PVC 2" waste tee and a short nipple sawed from 2" PVC.   These are what I made the new plenum from, the only alignment problems are from slider valve assembly.

The original plenum glued together.   The left end goes to the cylone's input, the right end will be capped (no glue).   Later I added a 4th valve on the left end.

Please see the Slide Valve page.

The plenum is strapped to the ceiling and the valves are inserted into the 3 ports (no glue).   You can see the center valve is open, the others are closed.   I use a small stick to open and close them.

A little different angle.   The flex pipe on the left connects the 2" manifold to the cyclone.   The cyclone's output is disconnected for a little better view of the valves and plenum.

The suction is very much improved.

Showing the 4th valve on the left.

Back side of the 4th valve and 2" duct over the workbench in the small bay.