Adsorption (desiccant) dryer

The desiccant has to be dried again to keep working, so the medical air dryers described in HTM 02-01 (2026) have two columns: one dries the compressed air while the other is regenerated with dry air from the active column, and a second complete dryer assembly keeps the supply going. Dryness is stated as pressure dew point, the temperature at which water would start to condense at working pressure, and ISO 8573-1 classes compressed air by its water content among other contaminants.

The ULTRADRY adsorption dryer gives a pressure dew point of −40 °C to −70 °C, with a coalescing filter at the inlet, a dust filter at the outlet and the desiccant in replaceable cartridges. Its table values are given at −40 °C pressure dew point with inlet air at 35 °C and 7 bar g, and it works from 4 to 16 bar g. ULTRADRY is an option on ULTRAAR ME medical air plants, and the ACIH hospital industrial air system can take adsorption dryers for dew points of −20 °C or −40 °C.