F
OR
M
ODELS
: JGI, JGM, JGN, JGP
AND
JGQ
S
ECTION
4 L
UBRICATION
PAGE 4-19
order to protect the compressor cylinder, any piping or vessels downstream of the screen
must be thoroughly cleaned to be sure that no debris is present. Proper maintenance of the
inlet screens is required. Inlet debris strainers should be monitored by differential pressure
and cleaned before the differential pressure approaches the collapse pressure of the
screens.
High differential pressure alarm/shutdown switches can be used to protect against screen
collapse.
Injection Oil Inlet Filter
An in-line oil filter or fine screen is required between the oil supply or supply tank and the
force feed lubricator pumps. Ariel recommended filtration is 5 micron nominal. The compres-
sor filtration system is adequate for systems that use frame lube oil for the force-feed cylin-
der and packing injection. For separate force-feed lube oil supplies, a filter must be installed
by the packager.
Oil Dilution
Cylinder lubrication requirements will vary with the operating conditions and the composition
of the gas to be compressed. Careful consideration must be given to proper cylinder lubrica-
tion selection. The degree of cylinder oil lubrication dilution/saturation by the process gas
stream is influenced by the following factors:
1.
Process gas composition/Specific Gravity (SG) - usually the higher the SG, the
greater the oil dilution.
2.
Discharge gas pressure - the higher the pressure, the greater the oil dilution.
3.
Discharge gas temperature - the higher the cylinder discharge temperature, the
less the oil dilution.
4.
Lubricant selection - some types of oil are more prone to dilution than others.
Cylinder Oil Lubrication Examples
Refer to Table 4-9 for lubrication recommendations for various gas compositions and various
operating conditions. Note that lubrication rates can change with operating conditions. Lubri-
cating oil type will also vary with the composition of the gas which is to be compressed.
Independent force feed lube systems require oil with a viscosity below 5000 SUS (1100 cSt)
at the lubricator pump inlet. Measures which may be necessary to make sure that the force
feed pump is filled with oil during the suction stroke include; appropriate pipe and fitting size
from the tank to the force feed pump, heating the oil, and pressurizing the supply tank.
Under/Over Lube
Inadequate
- (under) lubrication. This condition results in extremely rapid breakdown of pis-
ton and packing ring materials. Black, gummy deposits which can be found in the distance
piece, packing case, cylinder and valves are indicators of under lubrication.