Bendix Commercial Vehicle Systems AD-IS AIR DRYER AND RESERVOIR SYSTM User Manual

Bendix® AD-IS® and AD-IS® PuraGuard® (Oil Coalescing) Air Dryer and Reservoir Systems

RES

GOVERNOR

RESERVOIR (2)

SD-08-2418

PRESSURE

PROTECTION

VALVES (4)

PURGE

RESERVOIR

UNL

GOVERNOR

UNLOADER (2)

SEC

DELIVERY TO

SECONDARY

RESERVOIR

PRI

DELIVERY TO PRIMARY

RESERVOIR

GOVERNOR

EXH

GOVERNOR

EXHAUST

PURGE VALVE

DESICCANT CARTRIDGE

(STANDARD SHOWN)

AIR DRYER

PART NUMBER

STAMPED HERE

SAFETY VALVE

MOUNTING

BOLTS (3)

SUPPLY FROM COMPRESSOR

DESICCANT CARTRIDGE

(PURAGUARD®

OIL COALESCING

SHOWN)

HEATER /

THERMOSTAT

PRESSURE PROTECTION

VALVES (4)

MOUNTING

HOLES (4)

AUX2

AUXILIARY DELIVERY

PORT

AUX1

AUXILIARY

DELIVERY PORTS

(4)

FIGURE 1 - BENDIX® AD-IS® AND AD-IS® PURAGUARD® OIL COALESCING AIR DRYER AND RESERVOIR SYSTEMS

DESCRIPTION

The function of both the Bendix® AD-IS® (Integrated Solution Air Dryer) air dryer and reservoir system and the Bendix®

AD-IS® PuraGuard® oil coalescing air dryer and reservoir system is to collect and remove air system contaminants in solid, liquid and aerosol form before they enter the brake system and to provide—as a module—heavy vehicles with an integrated vehicle air dryer, purge reservoir, governor and a number of the charging valve components in a module. These components have been designed as an integrated air supply system.

Both air dryer and reservoir systems provide clean, dry air to the components of the brake system which increases the life of the system and reduces maintenance costs. The necessity for daily manual draining of the reservoirs is eliminated.

Air Connection

Port ID

IN 21

PRI

SEC

AUX 1

AUX 2

UNL Unloader Control Air (D-2A

RES Common Reservoir Pressure (D-2A™ Governor) 2

EXH Governor Exhaust 1

Inlet Port (air in) 1

Delivery Port Out (to Primary Reservoir) 1

Delivery Port out (to Secondary Reservoir) 1

Auxiliary Delivery Port (air out) 4

Auxiliary Delivery Port (air out) 1

Function/

Connection

TABLE 1 - PORT DESIGNATIONS

™

Governor) 2

QTY

DESICCANT

BED

OIL COALESCING FILTER

(BENDIX® AD-IS® PURAGUARD®

OIL COALESCING AIR DRYER)

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 ﬂ ow 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.

UNLOADER

PORT

SUPPLY

PORT

PURGE CONTROL CHANNEL

GOVERNOR

PURGE VALVE

(CLOSED)

COMPRESSOR

DELIVERY

CHECK VALVE

(OPEN)

ENGINE

TURBO

CUT-OFF

VALVE

(OPEN)

SEE

NOTE 1

SAFETY

VALVE

SECONDARY

PORT (SEC)

PRIMARY

PORT (PRI)

PRIMARY

RESERVOIR

AUXILIARY PORTS

(TO ACCESSORIES)

PRESSURE

PROTECTION

VALVES

DRAIN VALVE

PURGE

ORIFICE

PURGE

RESERVOIR

PURGE

RESERVOIR

SECONDARY

RESERVOIR

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

The Bendix® AD-IS® PuraGuard® oil coalescing air dryer has an identical appearance to the standard AD-IS® air dryer, but contains a coalescing media at the inlet of the

Note: Unless otherwise stated in this manual, AD-IS air dryer and reservoir systems refers to both the standard and

PuraGuard oil coalescing air dryer and reservoir systems. desiccant bed. The coalescing media provides a higher level of oil removal over the standard AD-IS air dryer. The AD-IS PuraGuard oil coalescing air dryer has all of the same functions as the standard AD-IS air dryer and is used in applications where lower oil concentration levels are required.

The function of the pressure protection valves is to protect

each reservoir from a pressure loss in the other reservoir or

a pressure loss in an air accessory . Each of the pressure

protection valves in the AD-IS air dryer and reservoir

systems may have different pressure settings. These are

factory set and must not be changed or adjusted. Important! When servicing, note that standard AD-IS

air dryers or air dryer cartridges may be serviced with PuraGuard oil coalescing air dryers or cartridges, however, PuraGuard oil coalescing air dryers or cartridges must only

The air dryer and reservoir system consists of a “spin on”

desiccant cartridge secured to a base assembly. The

base assembly contains a delivery check valve assembly , be serviced with like replacements.

DIAGRAM SHOWS ALL PRESSURE

PROTECTION VALVES OPEN.

DESICCANT

BED

OIL COALESCING FILTER

(BENDIX® AD-IS® PURAGUARD®

OIL COALESCING AIR DRYER)

UNLOADER

PORT

SUPPLY

PORT

PURGE CONTROL CHANNEL

GOVERNOR

PURGE VALVE

(OPEN)

COMPRESSOR

DELIVERY

CHECK VALVE

(CLOSED)

ENGINE

TURBO

CUT-OFF

VALVE

(CLOSED)

EXHAUST

SAFETY

VALVE

SECONDARY

PORT (SEC)

PRIMARY

PORT (PRI)

PRIMARY

RESERVOIR

AUXILIARY PORTS

(TO ACCESSORIES)

PRESSURE

PROTECTION

VALVES

PURGE

ORIFICE

PURGE

RESERVOIR

DRAIN VALVE

PURGE

RESERVOIR

SECONDARY

RESERVOIR

FIGURE 3 - BENDIX® AD-IS® AIR DRYER AND RESERVOIR SYSTEM PURGE CYCLE

safety valve, heater and thermostat assembly, pressure protection valves, threaded air connections and the purge valve assembly.

The removable purge valve assembly incorporates the purge valve mechanism and a turbocharger cut-off feature that is designed to prevent loss of engine “turbo” boost pressure during the purge cycle of the Bendix® AD-IS® air dryer and reservoir system. For ease of maintenance, all

BENDIX® AD-IS® AIR DRYER AND RESERVOIR SYSTEM OPERATION: GENERAL

(Refer to Figure 2.)

The AD-IS air dryer and reservoir systems are designed to receive compressed air from the vehicle air compressor, clean and dry the air, deliver air to the vehicle’s primary reservoir, secondary reservoir and accessories, and control the compressor/dryer charge cycle.

replaceable assemblies can be serviced without removal of the air dryer and reservoir system from its mounting on the vehicle. Refer to Preventive Maintenance section.

DIAGRAM SHOWS ALL PRESSURE

PROTECTION VALVES OPEN.

AIR DRYER AND RESERVOIR SYSTEM OPERATION: GENERAL

The Bendix® AD-IS® air dryer and reservoir system alternates between two modes or “cycles” during operation: the Charge Cycle and the Purge Cycle. The following describes these “cycles” of operation.

CHARGE CYCLE (Refer to Figure 2.)

When the compressor is running loaded (compressing air), compressed air ﬂ ows 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 ﬂ ows into the desiccant cartridge, where it ﬂ ows through an oil separator—or coalescing ﬁ lter if equipped with a PuraGuard® oil coalescing cartridge— which removes water in liquid form as well as liquid oil and solid contaminants.

Air then ﬂ ows 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 ﬂ ows to the delivery check valve and through an oriﬁ ce 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 ﬁ lls, 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 accessories. If the pressure protection valves are preset to different values the valves will open—in order of lowest setting to highest setting—when charging a ﬂ at system.

The air dryer and purge reservoir will remain in the charge cycle until the air brake system pressure builds to the governor cut-out setting of approximately 130 psi.

PURGE CYCLE (Refer to Figure 3.)

When air brake system pressure reaches the cut-out setting of the governor, the governor unloads the compressor activating the purge cycle of the air dryer and reservoir.

The governor unloads the compressor by allowing air pressure to ﬁ ll the line leading to the compressor unloader mechanism. This suspends the delivery of compressed air to the AD-IS

air dryer and reservoir system.

Similarly , the governor also supplies air pressure to the air dryer. The pressure also moves the air dryer purge piston down, opening the purge valve to atmosphere and closing off the compressor air supply to the turbo cut-off valve (covered in the Turbo Cut-of f Feature section of this piece). Water and contaminants captured are expelled immediately when the purge valve opens. In addition, air—which was ﬂ owing through the desiccant cartridge—changes direction and begins to ﬂ ow toward the open purge valve. Contaminants collected by the air dryer are removed by air ﬂ owing from the purge reservoir through the desiccant drying bed to the open purge valve.

The initial purge and desiccant cartridge decompression lasts only a few seconds, evidenced by an audible burst of air at the air dryer exhaust.

The actual regeneration of the desiccant drying bed begins as dry air from the purge reservoir ﬂ ows through the purge oriﬁ ce into the desiccant bed. Pressurized air from the purge reservoir expands after passing through the purge oriﬁ ce; its pressure lowers and its volume increases. The ﬂ ow of dry air through the drying bed regenerates the desiccant material by removing any water vapor adhering to it. Approximately 30 seconds are required for the entire contents of the purge reservoir of an AD-IS air dryer and reservoir system to ﬂ ow through the desiccant drying bed.

The delivery check valve assembly prevents air pressure in the brake system from returning to the air dryer during the purge cycle. After the purge cycle is complete, the air dryer and reservoir system is ready for the next charge cycle to begin.

TURBO CUT-OFF FEATURE (Refer to Figure 3.)

The primary function of the turbo cut-off valve is to prevent loss of engine turbocharger air pressure through the AD-IS air dryer when the dryer is in the purge mode.

At the onset of the purge cycle, the downward travel of the purge piston is stopped when the turbo cut-off valve (the tapered portion of purge piston) contacts its mating metal seat in the purge valve housing. With the turbo cut-off valve seated (in the closed position), air in the compressor discharge line—as well as the AD-IS air dryer inlet port— cannot enter the air dryer. By completing these actions, the turbo cut-off effectively maintains turbo charger boost pressure to the engine.

PREVENTIVE MAINTENANCE

Important: Review the warranty policy before performing

any intrusive maintenance procedures. An extended warranty may be voided if intrusive maintenance is performed during this period. Purge valve maintenance is permissible during the warranty period only when using a genuine Bendix

Because no two vehicles operate under identical conditions, maintenance and maintenance intervals will vary . Experience is a valuable guide in determining the best maintenance interval for any one particular operation.

purge valve kit.

Every 900 operating hours, or 25,000 miles, or three (3) months:

1. Check for moisture in the air brake system by opening reservoir drain valves and checking for the presence of water. If moisture is present, the desiccant cartridge may require replacement; however, the following conditions can also cause water accumulation and should be considered before replacing the desiccant:

A. An outside air source has been used to charge the

system. This air did not pass through the drying bed.

B. Air usage is exceptionally high and not normal for

a highway vehicle.

This may be due to accessory air demands or some

unusual air requirement that does not allow the compressor to load and unload (compressing and non-compressing cycle) in a normal fashion. Check for high air system leakage. If the vehicle vocation has changed, it may be necessary to upgrade the compressor size. Refer to Bendix Speciﬁ cation BW-100-A / Appendix D, to determine if any changes are necessary . Speciﬁ cation BW-100-A is available from the Bendix TechTeam at 1-800-247-2725 or www.bendix.com.

C. The location of the air dryer and reservoir system

is too close to the air compressor. Refer to Bendix Speciﬁ cation BW-1 10-A / Appendix B, for discharge line lengths.

D. In areas where more than a 30 degree range of

temperature occurs in one day, small amounts of water can temporarily accumulate in the air brake system due to condensation. Under these conditions, the presence of small amounts of moisture is normal.

For Bendix® AD-IS® PuraGuard® oil coalescing

air dryers only - every 3,600 operating hours, or 100,000 miles, or 12 months:

Oil removal requirements for air brake quality vary

by vehicle manufacturer. Because vehicle vocation

HEATER & THERMOSTAT

CONNECTOR

FIGURE 4 - HEATER AND THERMOSTAT CONNECTOR

and maintenance can inﬂ uence when the Bendix® AD-IS® PuraGuard® oil coalescing air dryer cartridge requires replacement, each ﬂ eet should modify their replacement schedule based on experience. The change out interval will be extended if the compressor passes a low level of particles. The interval will be reduced if excessive carbon particles are delivered to the dryer inlet. Higher compressor build up times at idle, as well as water or oil in downstream reservoirs indicate an AD-IS PuraGuard oil coalescing air dryer desiccant cartridge may need to be replaced.

Note: A small amount of oil in the system is normal and

should not be considered as a reason to replace the desiccant cartridge. Some oil at the dryer exhaust is also normal.

2. Visually check for physical damage, such as chaffed or broken air and electrical lines, and broken or missing parts.

3. Check the AD-IS® air dryer and purge reservoir bolts for tightness. See Figure 1. Re-torque the three air dryer bolts to 360–420 in-lbs and the four purge reservoir bolts to 300–360 in-lbs.

4. Perform the Operation & Leakage Tests listed in this publication.

WARNING!

This air dryer is intended to remove moisture and other contaminants normally found in the air brake system. Do not inject alcohol, anti-freeze, or other de-icing substances into—or upstream of—the air dryer and reservoir system. Alcohol is removed by the dryer, but reduces the effectiveness of the device to dry air. Use of these or other substances can damage the air dryer and may void the warranty.

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