Heavy Duty Balanced Opposed Compressors

FOR MODELS: JG AND JGA SECTION 4 - LUBRICATION AND VENTING
Force Feed Lubrication System - Description
The force feed lubrication system provides oil to the compressor cylinders and the piston rod
packings. Refer to Figure 4-8: on page 4-18.
All cylinders have both top and bottom lubrication injection points available as an original
order option, except for the 1-3/4JG-HE and 13-1/2JG class cylinders where “both top and
bottom” is provided.
Oil is supplied to the 150 micron sintered bronze filter on the suction side of the force feed
lubricator pump directly from the pressure side of the frame lube oil system, or from an overhead
tank (see Figure 4-9: on page 4-20). The filter, that prevents large particles from entering
the pump, is mounted on the lubricator box using a bracket. The filter inlet is on the side
of the filter housing and is provided with a 1/4 inch tube fitting connection.
The lubricator box has its own oil reservoir to lubricate the worm gear and cam. The reservoir
is self-contained and is not directly fed by the lube oil system. Lubricator pump overflow
spills into the lubricator box reservoir. A drain prevents the reservoir from overflowing. A
sight glass on the lubricator will show the oil level in the lubicator reservoir. Refer to Figure
5-10: on page 5-17.
There are 1/4 inch tube fitting connections in the discharge line near the force feed lubricator
pump through which the force feed lubricator system may be primed. See “Priming/Purging
the Force Feed System” on page 3-9.
Next in the discharge line is a blow-out disc. If there is a blockage in the system, the pressure
build-up will fracture the disc. Venting the system through the blow-out disc causes the
no-flow shutdown switch to close.
The oil then travels to the distribution block. It is here that the lubricating oil is apportioned to
provide the exact amounts to the cylinders and packings. The pistons in the intermediate
sections of the distribution block move back and forth in a continuous cycle, forcing lubricant
successively through the several outlets as long as lubricant is supplied under pressure at
the inlet. Each outlet has a check valve to prevent oil from backing up in the block. An indicator
on the block shows the rate at which the block is cycling. A pressure gauge is provided at
each distribution block inlet to show system pressure.
From the distribution block, oil travels to the cylinders and packings.
Check valves are located at each injection point where 1 inch minimum (25mm) of head is
provided to ensure reliable check valve operation and to lengthen check valve life. At lube
points where 1 inch of head is not feasible, an oil trap fitting is installed (refer to Figure 4-7:
on page 4-18).
Some of the oil to the packing travels through to the cylinders, but the bulk of it is drained out
through the pressure vent/drain fitting on the bottom of the crosshead guide and through the
atmospheric drain also in the bottom of the guide.
An oil level control valve, supplied by the packager and mounted on the skid, maintains
proper level in the crankcase sump to replace oil used in cylinder lubrication.
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