John K Jordan
>>>2. It conducts/dissipates heat and thus operates to cool the air stream that works to condense water and oil vapor out of the compressed airflow. With line drain legs and keeping your storage tank dry you get much drier/cleaner air...
Recommendations I've read are to run copper the first 20' or so from the compressor, the pipe sloped downward so condensate can run downhill and drip into the sump/drain leg. This is before the any dryers. If a centrifugal water trap is too near the compressor much of the hot moist air will pass right through and condense further down the line and perhaps get sprayed onto your project!