... cost. Heat-less,twin-tower,regenerative,desiccant air dryers,refrigerated air dryer,air cooled chillers KC DRYERS DELIVER-PERFORMANCE,RELIABILITY, ... 4-way sliding spool valves which allow purge air containing abrasive desiccant dust to be channeled back through ... poppet-style purge exhaust valves,designed to handle purge air containing abrasive desiccant dust. ο Epoxy encapsulated, tamper-proof ...