Page 303 - Reciprocating Compressors Operation Maintenance

288 Reciprocating Compressors: Operation and Maintenance

the piston is causing the piston rod to bend. Remove piston from
piston rod and repeat checks described earlier under Inspection of
Compressor Pistons.

This problem must be corrected before use, or a broken piston rod will
almost certainly result.

Whenever the piston rod has been removed or even turned in or out of
the crosshead, it is necessary to check the piston end clearance and make
any adjustments necessary to restore it to the proper amount. If the piston
has not been removed from the rod, the original clearance can easily be
maintained by center punching both the rod and the crosshead and mak-
ing a suitable scribing tool, as shown in Figure 4-39, before removing the
rod from the crosshead.
Note: The length of the scribing tool will vary depending on the size of
the crosshead nut, and care must be taken to locate scribe marks so that

TOP
CROSSHEAD SHOE

CROSSHEAD
PM
LOCK NUT

CROSSHEAD
SHOE STUD

FIGURE 4-39. Tramming tool used to verify location of piston rod relative to
crosshead.