BENDIX BW1948 manual AIR Dryer Operation General, Turbo Cutoff Valve Safety Open Purge See

DESICCANT

BED

				OIL
				SEPARATOR
GOVERNOR	DELIVERY
	CHECK					PURGE
	VALVE						PURGE
						ORIFICE
	(OPEN)						RESERVOIR
UNLOADER
PORT
				PRESSURE PROTECTION
	PURGE			VALVES
INLET
	CONTROL
PORT	CHANNEL		A
(IN)
				B	C	D
	TURBO
	CUTOFF
	VALVE		SAFETY
	(OPEN) PURGE	SEE
			VALVE				SECONDARY
	VALVE	NOTE 1	PRIMARY	AUXILIARY PORTS
							RESERVOIR
	(CLOSED)		PORT
				(TO ACCESSORIES)
			(PRI)
						PURGE
						RESERVOIR
						DRAIN VALVE

ENGINE

TURBO

COMPRESSOR

PRIMARY

RESERVOIR

Note 1:

The AD-IS®air dryer purge piston has a purge control channel drain. This allows any condensation in this area to flow past a diaphragm in the top of the purge piston and out through a channel in the middle of the central bolt of the purge assembly to be drained. During the purge cycle this drain is closed.

FIGURE 2 - AD-IS®AIR DRYER CHARGE CYCLE. DIAGRAM SHOWS PRESSURE PROTECTION VALVES A AND B OPEN, C & D CLOSED.

The removable purge valve assembly incorporates the purge valve mechanism and a turbocharger cutoff feature that is designed to prevent loss of engine “turbo” boost pressure during the purge cycle of the AD-IS®air dryer. For ease of serviceability, all replaceable assemblies can be replaced without removal of the air dryer from its mounting on the vehicle. Refer to Preventive Maintenance section.

DRM™ DRYER MODULE OPERATION: GENERAL (Refer to Figure 2)

The DRM™ dryer module is designed to receive compressed air from the vehicle air compressor, clean and dry the air using the AD-IS®air dryer, deliver air to the vehicle’s primary

reservoir, secondary reservoir and accessories, and control the compressor/dryer charge cycle.

AIR DRYER OPERATION: GENERAL

The AD-IS®air dryer alternates between two operational modes or “cycles” during operation: the Charge Cycle and the Purge Cycle. The following descriptions are separated into these “cycles” of operation.

CHARGE CYCLE (Refer to Figure 2)

When the compressor is loaded (compressing air) compressed air, along with oil, oil vapor, water and water

2