BENDIX SD-08-2418 manual Charge Cycle Refer to Figure

DESICCANT

BED

OIL COALESCING FILTER

(BENDIX® AD-IS®PURAGUARD®

OIL COALESCING AIR DRYER)

DELIVERY

PURGE CHECK VALVE

CONTROL (OPEN)

CHANNEL

GOVERNOR

UNLOADER

PORT

Note 1:

The Bendix® AD-IS®air dryer and reservoir system 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.

PURGE

PURGE RESERVOIR

ORIFICE

PRESSURE

PROTECTION

VALVES

SUPPLY	PURGE VALVE	A	B	C	D
PORT
	(CLOSED)	PRIMARY
	TURBO
		SAFETY PORT (PRI)
	CUT-OFF				PURGE
		VALVE
	VALVE
		SECONDARY			RESERVOIR
	ENGINE (OPEN)
					DRAIN VALVE
	TURBO	PORT (SEC)		PRIMARY
	COMPRESSOR	SEE	RESERVOIR		SECONDARY
		NOTE 1
					RESERVOIR
				AUXILIARY PORTS
				(TO ACCESSORIES)

DIAGRAM SHOWS ALL PRESSURE

PROTECTION VALVES OPEN.

FIGURE 2 - BENDIX® AD-IS®AIR DRYER AND RESERVOIR SYSTEM CHARGE CYCLE

CHARGE CYCLE (Refer to Figure 2.)

When the compressor is running loaded (compressing air), compressed air flows through the compressor discharge line to the inlet (1/IN) port of the air dryer body. The compressed air often includes contaminates such as oil, oil vapor, water, and water vapor.

Traveling through the discharge line and into the air dryer, the temperature of the compressed air falls, causing some of the contaminants to condense and drop to the bottom of the air dryer and purge valve assembly. These contaminants are ready to be expelled at the next purge cycle. The air then flows into the desiccant cartridge, where it flows through an oil separator—or coalescing filter if equipped with a Bendix® PuraGuard® oil coalescing cartridge—which removes water in liquid form as well as liquid oil and solid contaminants.

Air then flows into the desiccant drying bed and becomes progressively more dry as water vapor adheres to the desiccant material in a process known as adsorption.

Dry air exits the desiccant cartridge, through the center of the base assembly, then flows to the delivery check valve and through an orifice and into the purge reservoir. The delivery check valve opens, supplying air to the pressure protection valves (A) through (D) simultaneously, the safety valve, and also to the reservoir port of the attached governor. The purge reservoir fills, storing air that will be used to regenerate the desiccant during the purge cycle. This air is available to supply downstream components during the charge mode.

When the air pressure reaches approximately 106 psi, the four pressure protection valves will open and air will be supplied to the primary reservoir, secondary reservoir, and

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