Ariel JGJ Series, Technical Manual

Page: 49 / 141

F
OR
M
ODELS
: JGW, JGR
AND
JGJ S
ECTION
4 - L
UBRICATION AND
V
ENTING
1/01 PAGE 4 - 5
Oil sampling should be performed on a regular basis to verify suitability of oil for continued
service. Degradation to the next lower viscosity grade below the original viscosity or an
increase in viscosity to the next higher grade requires a complete oil change. Viscosity test-
ing should be performed at 212°F (100°C).
Cylinder And Packing Lubrication Requirements
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.
Please refer to Table 4-1 on page 4-8 for lubrication recommendations for various gas com-
positions and various operating conditions. Note that lubrication rates can change with oper-
ating conditions. Lubricating oil type will also vary with the composition of the gas which is to
be compressed.
Common Oil Supply - When process gas composition and cylinder operating conditions
allow compressor frame lubricating oil to be used for cylinder and packing lubrication, the
resulting force feed lube systems are installed as shown in Figure 4-7: on page 4-17.
Independent Oil Supply - When process gas composition and cylinder operating conditions
require an independent cylinder oil supply, the resulting separate force feed lube systems
require an oil supply as shown in Figure 4-8: on page 4-19. Lubricator oil is supplied under
pressure from an elevated tank. To ensure that the compressor frame oil is not contami-
nated, be sure that the force feed lubricator box over flow does not drain into the crankcase.
This over flow tubing must be disconnected from the compressor frame and directed to an
appropriate drain system.
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. An in-
line oil filter or fine screen is required between the supply tank and the force feed lubricator
pumps. Recommended filtration is 20 micron nominal.
Inadequate (under) lubrication results in a “mini-lube” condition. This condition results in
extremely rapid breakdown of Teflon and PEEK piston 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.
Excessive (over) lubrication can result in excessive oil carryover into the gas stream, and
increased quantities of deposits in the valves and gas passages. Valve plate breakage and
packing failure are also symptoms of over lubrication. The packing case will “hydraulic”,