Thermal
Growth
Compressor
Centerline
HOT
Compressor
Centerline
COLD
FIGURE 2-5
Compressor
Thermal Growth
TABLE 2-4 Typical Thermal Growth Predictions
Frame Model
THERMAL GROWTH
Inches
(mm)
JGM:N:P:Q
0.006
(0.15)
JG:A:I
0.007
(0.18)
JGR:W:J
0.008
(0.20)
JGH:E:K:T
0.011
(0.28)
JGC:D
0.014
(0.36)
JGZ:U
0.016
(0.41)
KBB:V
0.018
(0.46)
JGB:V
0.020
(0.51)
F
OR
M
ODELS
: JGI, JGM, JGN, JGP
AND
JGQ
S
ECTION
2 - I
NSTALLATION
PAGE 2-10
Cold Alignment
Align the compressor to the
driver taking into account the
difference in thermal growth
between the compressor and
driver, so the face and rim TIR
measurements at the coupling
will be within the Figure 2-3 lim-
its when equipment warms to
the normal operating tempera-
tures. Reference Figure 2-5 and
Table 2-4 for the compressor
centerline height change, based
on 6.5 x 10
-6
/°F (11.7 x 10
-6
/°C)
and a typical differential temper-
ature increase of 100°F
(55.6°C). For other significantly
different predicted differential
temperature increases, the ther-
mal growth value may be calcu-
lated for the compressor. Refer
to the driver manufacturer’s
thermal growth prediction for
the driver differential tempera-
ture increase to normal operat-
ing temperature.
When larger compressors are
shipped with the crosshead
guides removed, it may be desirable to align the frame to the driver prior to installing the
guides and crossheads. Frames shipped without guides after July 13, 2007 are provided
with temporary plates, through bolts and protective sleeves at each connecting rod bushing.
This allows for the frame to be properly pre-lubed prior to turning the crankshaft for align-
ment. The temporary hardware at the connecting rods is then removed (and discarded) prior
to installing the crosshead guides and crossheads. When removing this temporary hard-
ware, oil may flow from the rod bushing cavity behind the plates. A catch basin to prevent oil
spillage is recommended.
Hot Alignment
After 24 to 48 hours of full load operation, or when entire skid and block mount is heat
soaked, TIR measurements at the rim of the coupling are not to exceed 0.005 inches
(0.13 mm) and on the face are to be within the Table 2-2 or Table 2-3 limits. If not within the
these limits, re-align the compressor.