Bendix Commercial Vehicle Systems AD-IP INTEGRAL PURGE AIR DRYER 5/07 - Manual (Page 2)

2
OPERATION
GENERAL
The AD-IP ™ air dryer alternates between two operational
modes or “cycles” during operation: the Charge Cycle and
the Purge Cycle. The following description of operation is
separated into these “cycles” of operation.
CHARGE CYCLE (refer to Figure 4)
When the compressor is loaded (compressing air)
compressed air, along with oil, oil vapor, water and water
vapor flows through the compressor discharge line to the
supply port of the air dryer body.
As air travels through the end cover assembly, its direction
of flow changes several times, reducing the temperature,
causing contaminants to condense and drop to the bottom
or sump of the air dryer end cover.
After exiting the end cover, the air flows into the desiccant
cartridge. Once in the desiccant cartridge air first flows
through an oil separator located between the outer and inner
shells of the cartridge. The separator removes water in liquid
form as well as liquid oil and solid contaminants.
FEEDBACK
LINE
SPECIAL DISCHARGE
PORT FTG. W/
FEEDBACK LINE
CONNECTION CHECK
VALVE
DISCHARGE
PORT
SPECIAL DISCHARGE
PORT FTG. W/
FEEDBACK LINE
CONNECTION
END COVER
BOTTOM VIEW
LOWER
MTG. BRKT.
(PARTIAL) FEEDBACK
LINE
DISCHARGE LINE
HOLSET COMPRESSOR
SUPPLY
RES.
FIGURE A
HOLSET TYPE E & QE COMPRESSORS - NO AIR DRYER
FIGURE C
AD-IP ™ DI DROP IN AIR DRYER AND
HOLSET TYPE E & QE COMPRESSORS
AD-IP ™ DI DROP IN AIR
DRYER W/FEEDBACK
LINE & CHECK VALVE
SUPPLY
RES.
HOLSET
COMPRESSOR
FIGURE B
STANDARD AD-IP ™ AIR DRYER AND
HOLSET TYPE E & QE COMPRESSORS
FEEDBACK LINE
W/CHECK VALVE
SUPPLY
RES.
STANDARD AD-IP ™ AIR
DRYER
AD-IP ™ DI “DROP IN” AIR DRYER MODEL
In addition to the standard AD-IP ™ air dryer, the Bendix ®
AD-IP ™ DI (Drop In) air dryer is also offered. It is a specialized
version designed especially for air systems that use either
the Holset (Cummins) Type E or QE air compressor. These
Holset compressors utilize an unusual unloading system
that requires that air pressure remain in the discharge line
during the entire unloaded cycle of the compressor. To
accomplish this, Holset compressors rely on air “feedback”
from the supply reservoir as shown in Figure 3B. When an
air dryer is installed the direct “feedback” from the supply
reservoir is interrupted and an alternate source for “feedback”
pressure must be provided. A standard AD-IP
™ air dryer can
be installed, however a separate “feedback” line with a single
check must be installed as shown in Figure 3C.
The AD-IP ™ DI drop in air dryer model incorporates the
feedback line and single check as an integral part of the
dryer and eliminates the need for these components as shown
in Figures 2 & 3C.
FIGURE 2 - AD-IP ™ DI DROP IN AIR DRYER FOR HOLSET
COMPRESSORS
FIGURE 3 - AD-IP ™ AIR DRYER AND HOLSET TYPE E & QE
COMPRESSORS
HOLSET
COMPRESSOR