"The accumulation of water in the vessel caused severe corrosion ..."
Every working compressor tank has water in the bottom all the time, drain
or no drain. The drain just keeps it from taking up a significant volume.
But you're wrong , Dick . A well-maintained tank will have very little
water in the bottom . Our tanks at work (cabinet shop) all have automatic
drains , in addition to dryers between the tank and compressor .
"Very little", eh?
Some liquid will always be there, and the atmosphere is at 100 percent
So from a corrosion standpoint, draining has no effect. There is always
some standing liquid water.
Which always leave some liquid in the tank, and do absolutely nothing to
the condensing ambient atmosphere in the tank.
Which has nothing to do with conditions inside the tank itself.
Now, a dryer between the compressor pump and the tank, that could be
putting dry air in the tank, which is the only way around this problem.
Don't be ignorant and think that draining a tank has anything to do with
corrosion protection. You drain tanks to minimize the buildup of volume
So, seeing that it really wouldn't add much to the production
costs of a tank, why don't they slosh some epoxy around inside it
after manufacture? They line gasoline storage tanks with epoxy to
prevent corrosion. It wouldn't be a big deal to have a device that
randomly tumbles a rack of clamped-in air tanks to move the stuff
around (like the PVC molding technology used to make big plastic water
tanks and dumpsters and the like) and then remove the plugs and tap
out the hardened epoxy from the pipe ports. If it's stuck good the air
won't get behind it and blow it off if the tank is drained.