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The Air Prep System is a Pressurized Vessel. Propelled objects will cause serious injury or
death. Depressurize vessel before performing any maintenance. See Section 6.2.
Figure 5.1 – Typical AirPrep Dryer System
5.11 Depressurize
(Blowdown)
The drain ball valve (#19) is used to release all the compressed air (depressurize) from inside the
AirPrep System separator tank (#20). The AirPrep System must be depressurized for filling with
deliquescent /desiccant tablets, or to perform any maintenance.
To depressurize the separator
tank pressure turn off the air compressor and/or close the compressor’s outlet valve, then slowly
open the drain ball valve (#19) located at the bottom of the tank (see Section 6.2). The drain ball
valve should be left closed anytime the unit in not in use. If the drain ball valve is left open, the
deliquescent/desiccant tablets will remove moisture from air entering from the outside the tank.
Airborne particles and loud noise hazards from blowdown exhaust air can cause serious injury
and loss of hearing. Wear approved eye and ear protection. Stay clear of blowdown air path. DO
NOT place hands or other body parts in the blowdown air path. Make sure no personnel are in
the blowdown air path.
5.12 After-Filter
The particulate after-filter (#5) removes particles of deliquescent or desiccant material that may
have been carried over from the separator tank. The after-filter also is the air source for the
aftercooler air motor (except on ADS 250). Any debris that is removed by the after-filter can be
drained through the drain valve (#7) located at the bottom of the after-filter. The drain ball valve
(#7) should be left closed anytime the AirPrep System is not in use.
