Heavy Duty Balanced Opposed Compressors - Ariel Corporation

FOR MODELS: JGZ AND JGU SECTION 5 - MAINTENANCE
Positioning a Throw for Maintenance
Compressor maintenance often requires manually rotating the crankshaft to locate a particular
throw in one of two positions: the inner dead center or the outer dead center. During normal
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 crankcase as far as possible
(see figures below). Some procedures, such as setting piston end-clearances, require
a dial indicator with magnetic base to locate the precise inner or outer dead center.
Connecting Rod
!
CAUTION
AFTER PERFORMING ANY MAINTENANCE, THE ENTIRE SYS-
TEM MUST BE PURGED WITH GAS PRIOR TO OPERATION, TO
AVOID A POTENTIALLY EXPLOSIVE AIR/GAS MIXTURE.
Inner Dead Center Position Outer Dead Center Position
In the figure to the right,
the throw on the left is in
its highest position and
the throw on the right is
in its lowest position.
Highest and Lowest Throw Position
FIGURE 5-1 THROW POSITIONING
The connecting rod has a tri-metal (steel, bronze, and babbitt with a tin flash coat) precision
split (2-piece shell) bearing. There are notches in the rod and rod cap for the bearing tabs in
order to position and maintain the position of the bearing halves.
Do not remove the connecting rod cap to check for bearing wear, if a cap is removed it is
recommended that a new bearing is installed, i.e. DO NOT REUSE BEARING SHELLS.
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