Heavy Duty Balanced Opposed Compressors - Ariel Corporation

For Models: JGH:E:K:T Section 3 - Maintenance
Checking Lubrication
Oil Pump
The oil pump constantly
supplies oil to all journal
bearings, bushings, and
crosshead sliding surfaces. It
directly couples to the
crankshaft by a chain and
sprocket and provides
adequate oil flow to bearings
when the compressor
operates at the minimum
speed rating (typically half of
maximum rated speed).
Discharge
Suction
Remove Dust Cap
to expose Safety
Relief Valve
Adjustment Screw. FIGURE 3-1 Lube Oil Pump - Typical
Crankshaft driven oil pumps maintain oil pressure with a spring-loaded safety relief within the pump
head (some models use a separate pressure regulator). To raise or lower lube system pressure,
adjust the spring compression on this valve.
With a separate oil pressure regulating valve, Ariel sets the spring-loaded safety relief within the
pump head to approximately 75 psig (5.2 barg ) to prevent high oil pump discharge pressures that
could damage the pump. In this case, do not adjust the pump safety relief valve except with a new
pump installation.
Oil Pressure Regulating Valve
Without a separate oil pressure regulating valve, Ariel sets the oil pump safety relief valve to regulate
pressure at 60 psig (4.1 barg ) into the compressor when crankshaft speed equals or exceeds
minimum normal operating speed. If oil pressure into the compressor at minimum operating speed
and normal operating temperature does not read about 60 psig (4.1 barg ), adjust the oil pump safety
relief valve. With compressor running at minimum rated speed, remove dust cap and turn the
adjustment screw clockwise to increase oil pressure, or counter-clockwise to decrease it.
With a separate lube oil pressure regulating valve, Ariel sets normal oil pressure into the compressor
at the regulating valve to 60 psig (4.1 barg ) when crankshaft speed equals or exceeds minimum
normal operating speed.
NOTE: If oil pressure drops below 50 PSIG (3.5 barg ) when crankshaft speed equals or
exceeds minimum rated operating speed, find the cause and correct it.
Low Oil Pressure Shutdown
The packager normally mounts a customer specified low oil pressure shutdown. Ariel provides an oil
pressure pickup fitting on the oil gallery located after the filter. Set the electric or pneumatic oil
pressure switch to actuate when oil pressure falls below 45 psig (3.1 barg). An alarm set to actuate
when oil pressure falls below 50 psig (3.4 barg) is desirable. Please note:
1. The compressor requires a working low oil pressure shutdown. When shut down as a result of
low oil pressure, DO NOT re-start until fault is found and corrected.
2. Do not add oil to the crankcase through the breather hole while the unit runs. This causes oil
foaming and unnecessary no-flow shutdowns in the force feed lubrication system.
3. When the force feed lubrication system has a common supply (from the crankcase), it constantly
uses oil from the crankcase. This requires an oil sump level controller designed to allow oil to flow
into the crankcase from an overhead tank at all ambient temperatures.
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