F
OR
M
ODELS
: JGI, JGM, JGN, JGP
AND
JGQ
S
ECTION
5 - M
AINTENANCE
PAGE 5-3
Compressor Components
Positioning a Throw for Maintenance
Compressor maintenance often requires manually turning the crankshaft to locate a particu-
lar throw in one of two positions: the inner dead center or the outer dead center. During nor-
mal operation, the crossheads slide back and forth in the crosshead guides. In the inner
dead center position, the crossheads slide in toward the crankcase as far as possible. In the
outer dead center position, the crossheads slide out away from the crank case as far as pos-
sible (see figures below). Some procedures, such as setting piston clearances, require a dial
indicator with magnetic base to locate the precise inner or outer dead center.
F
IGURE
5-1 C
OMPRESSOR
C
OMPONENTS
- T
YPICAL
JGM:N:P:Q
Compressor
Piston
Crankshaft
Connecting
Rod
Crosshead
Crosshead/Balance Nut
Eye Bolt
Lube Oil Filter
Piston Integral
w/Piston Rod
Compressor
Cylinder
Breather
FF Oil Distribution Block
Crosshead
Guide Cover
Valve Cap
VVCP
Compressor
Piston
Rod
Packing
Piston Rod
Rod
Packing
Connecting
Rod
Eye Bolt
Crosshead/
Balance Nut
VVCP
Valve Cap
Valve Cap
Valve
Cap
Compressor
Cylinder
Compressor Frame
w/Integral Crosshead
Guides
FF Oil Flow Monitoring Device
Eccentric
Chain Drive
Adjustment
Lube Oil
Pressure
Gauges
FF Blowout Disc
FF Lube Filter
FF Lubricator Box
Lube Oil
Pump
Lube Oil
Strarainer
Rod
Packing