How to centering reflux?

[TheMechwarrior]

I see a lot of talk about condensate running down the column and the need to center the flow to within the vapour path for best results.

I'm interested in hearing about successful methods people have used, particularly pictures.
I've heard of people using a concentric reducer welded to the inside of the pipe, is this the most common method?

Cheers,

Mech