TM 5-3895-374-24-2
SECTION VII
OPTIONAL EQUIPMENT AND ACCESSORIES
AIR-COOLED AFTERCOOLER
The purpose of an aftercooler is to reduce the
discharge temperature of the compressed air and to
facilitate removal of water vapor.
The cooler consists of finned tubing through which
compressed air passes on its way to the air receiver.
Cooling air drawn over these tubes by the fan-type
flywheel cools the compressed air and condenses
moisture. This moisture passes on to the receiver and is
drained either manually or by an automatic drain trap.
Figure 7-1. Typical Air-Cooled Aftercooler
Disassembled).
SERVICING - The air-cooled aftercooler will require
very little maintenance. The tubes should be blown
clean with compressed air monthly.
AUTOMATIC DRAIN TRAP
Figure 7-4. Inverted-Buckel, Automatic Condensate
Drain Trap.
When specified on the purchase order, units are
provided with an automatic condensate drain trap. The
purpose of the drain trap is to expel the condensate from the
receiver and/or the aftercooler.
WARNING
This machine contains high pressure air.
Can cause injury or death from flying
parts.
Always release pressure from compressor
and air receiver before removing caps,
plugs,
fittings,
covers,
priming
condensate trap; etc.
TO PRIME CONDENSATE TRAP
(See Figure 7-5)
Close manual shut-off valve installed in bottom side of
pipe tee. Remove pipe plug installed in top of pipe tee, and
pour water into top opening of pipe tee until trap and pipe tee
are filled with water. Open manual shut-off valve releasing
water in pipe tee into air receiver. Re-install pipe plug using
pipe thread lubricant and tighten to prevent air leak.
When the inverted-bucket-style, automatic condensate
drain trap is properly primed, and as pressure is built up in the
air receiver, condensate is forced into the trap and out the
trap outlet. However, if the trap is not properly primed, the
inverted bucket remains in its down position. This causes the
valve to remain open, allowing air pressure leakage to
atmosphere.
Where there is little or no condensate present in the air
receiver, the trap will continue to expel a small amount of air
pressure each time the inverted bucket loses buoyancy. The
amount of air pressure lost by the cycling of the inverted
bucked is negligible; however, it may present the appearance
of a faulty automatic condensate drain trap if this cycling is not
properly understood. It is very important to understand that
this small amount of intermittent air leakage is perfectly
normal and should not give cause for alarm. However, if air
leakage occurs on a continuous basis, it could be an
indication the trap has lost its prime through evaporation or
that the trap may be faulty.
TO PREVENT REPRIMING TRAP, CLOSE MANUAL SHUT-
OFF VALVE ON TRAP BEFORE COMPLETE AIR LOSS OF
RECEIVER.
Figure 7-5. Auto Drain Trap priming location.
page 3 - 843
