Page 60 - Improving Machinery Reliability
P. 60
32 Improving Machinery Reliability
IGAS REFERENCE 1,
- PURGE GAS
TANK
4
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1 // /I TO LEVEL
/, N CONTROL VALVE
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Holes:
valve and provides bearing lubrication to the unit. The tank volume vacated by the
lube oil is now occupied by air entering through (5) the vent check valve.
Vent check valves are however notorious leak paths. A superior rundown tank is
used by European compressor manufacturers. Instead of a vent check valve, their
designs employ an oversized return line to the reservoir. During rundown, the dis-
placed oil volume is taken up by air or nitrogen flowing upward from the reservoir in
the tank overflow line.
The preceding explanatory information was intended to demonstrate two main
points:
