spring, pin, oil seal, front seal, and the attaching
the crankshaft. On the upward stroke the third stage
hardware.
plunger compresses the air in the third stage cylinder
bore, as the inlet valve seats on the third stage 'valve
plate. As the pressure within the third stage cylinder
29. Functioning
starts to exceed the pressure on the outlet side of the
The compressor sections are joined together to form a
discharge valve the discharge valve unseats permitting
single working unit. The first, second, and third stage
the high pressure compressed air to pass to the
sections are assembled to the crankcase section. The
aftercooler and the water separator.
keystone-crankshaft section is located within the
crankcase section.
a. Keystote-Crankcase Section.
The keystone-
30. Maintenance
crankcase section, when powered by the gasoline
Fourth echelon maintenance personnel are authorized to
engine, provides oil pressure to the unit by the use of the
test and overhaul the compressor group. Overhaul of
gerotor and also activates the first, second, and third
the compressor group is accomplished by replacement
stage sections.
and overhaul of detail components and attaching
b. First Stage Section.
The first stage section
hardware in each section, using repair part kits for each
filters and draws air into the first stage cylinder bore on
section.
the downward stroke of the first stage piston. On the
a. ThIrd Stage Section.
Third stage section
upward stroke of the first stage piston, the inlet valve
overhaul is accomplished by replacing the elbow fitting,
seats on the valve plate and the discharge valve unseats
second stage relief valve, head assembly, valve plate,
permitting the compressed air to flow through the first
plunger and cylinder, and spacer.
stage intercooler to the inlet port of the second stage
Caution: The plunger and- cylinder are matched
section.
parts and are not replaceable separately.
c. Second Stage Section.
The second stage
Repair parts for the third stage section are included in
section accepts the low pressure compressed air, which
the third stage repair kit.
unseats the inlet valve in the second stage. The low
b. Second Stage Section. Second stage section
pressure air forces the second stage plunger downward
overhaul is accomplished by replacing the inlet elbow,
to follow the key-stone on the crankshaft. The rotation
outlet elbow, head assembly, second stage valve plate,
of the crankshaft moves the keystone in a circulatory
washers, and second stage plunger assembly. Repair
manner so that at the bottom of the downward stroke,
parts are included in the second stage repair kit.
the second stage plunger is forced in the reverse
c. First Stage Section.
First stage section
direction.
On the upward stroke, the second stage
overhaul is accomplished by replacing the outlet elbow,
plunger starts to compress the air in the second stage
cap, head assembly, discharge seat, valve plate, spacer,
cylinder bore. As soon as the air pressure in the second
piston plug, piston pin assembly, and first stage piston.
stage is greater than the incoming air from the first stage
Repair parts are included in the first stage repair kit.
section, the second stage inlet valve seats on the valve
d. Keystone-crankshaft Section.
Keystone-
plate.
The discharge valve is unseated permitting
crankshaft section overhaul is accomplished by
passage of the intermediate pressure from the second
replacement of the connector, adapter assembly, back-
stage section to the second stage intercooler, second
up plate, keystone assembly, front bearing, rear bearing,
stage relief valve and the inlet port of the third stage
crankshaft assembly, gerotor assembly, and retaining
section.
ring.
d. Third Stage, Section. The third stage section
Caution: The keystone assembly consists of
accepts the intermediate pressure which unseats the
matched parts and is not interchangeable with
inlet valve in the third stage. The intermediate pressure
similar parts of other keystone assemblies.
forces the third stage plunger downward to follow the
e. Crankcase Section. Crankcase section over-
keystone on
haul is accomplished by the replacement of
AGO 5548A
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