DIY: Dual Catch Cans with Air/Oil Separators... On the CHEAP!

SouthArk370Z

Not sure that what I learned about flow measuremnt applies here but it looks to me like the slots would accomplish two things:
1) create turbulence inside the tube to cause the oil droplets to come in contact with the tube wall and each other and coalesce.
2) bleed off some of the slower moving air along the pipe wall to reduce the velocity in the tube.

Edit: If the velocity inside the tube is low (say, inches/minute), then the slots won't do much but look pretty.

But I may be way off base.

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