refrigerated air dryer - how does it work?

[BrianE22]

Our refrigerated air dryer plugs up occasionally - no air flow. I'm guessing that moisture maybe freezes and plugs the line. It seems odd that water never drains from the automated drain line. So before I take it apart I was wondering how the heat transfer works. Do they just wrap the cold copper refrigerant lines around the compressed air lines? I saw some literature that talked about a demister? Any idea what that is?

 

[btrueblood]

Demister is a screen or series of them, intended to force very small condensation droplets to impinge on a surface, coalesce, and (eventually) drip to a sump.

 

[quark]

Condensation of vapor in compressed air occurs in a heat exchanger (heat exchange between refrigerant and compressed air)and then moisture removal is done by centrifugal separation. Demister pads can can be other option.

Drain trap problem can be cause as well as effect. If your demister pad is clogged, due to oil traces in compressed air or dust accumulation, air flow gets reduced and there won't be any air flow. If the drain trap started malfunctioning, may be some ice might have formed in the separator and heat exchanger.

Flush the dryer with compressed air (with dryer off) and see for improvement.