Originally Posted by oldred
It's to remove water from the air, if you just run a hose directly from the compressor tank you will have a LOT of water in your air supply! By using all that metal pipe you remove most of this water because it will condense on the pipe walls and drain into the collection drops instead of exiting the end of the air hose and into your tools, paint (water drops in paint!
), etc. As the air comes from the tank during heavy use it will still be hot from the compression process so the moisture it contains will be in vapor form which will mostly just pass right through a moisture separator. The metal piping then acts as a heat exchanger that cools the air and allows the vapor to condense into liquid water that can be collected and drained, without this you could almost water your lawn with your air hose on a humid day! Well not actually that bad but you do get a lot of liquid water mixed with your air as the water vapor condenses as it expands and cools.
Interesting. I've used portable compressors, for the most part, and haven't had any issues. Yes, there is moisture in the hose sometimes but it hasn't caused any problems yet. I don't paint though and don't intend to. My intention was too just mount hose reel right above the compressor and just use whatever I needed to connect it to the compressor. I could install some pipe though. What is the minimum generally needed?