Are you talking about desiccant based room air dryers or compressed
air dryers?

Compressed air dryer. Guess I should have said that in the begining.

A piece of 3" pipe with two threaded end caps. Drill and tap the end
caps for 1/4" NPT, fill the pipe with silica gel and a bit of angel
hair on the ends and you should be set.

Gerry,
I like your idea. Thanks.
Dan