Appendix 2-2
2-2-2 Oil Separator
Similarly to the case of single package, the oil separator type can be selected according to the
system and the application.
When the common separator is used, it is necessary to consider the separator size and adding of
secondary separator depending on the swept volume of the compressor and the target oil carry
amount. Therefore, selecting is possible from either one of cyclone type, demister type, and
coalescer type. In case of horizontal type oil separator, of which oil accumulates inside, it is also
possible to return oil to the suction side at the upstream side of the compressor.
2-2-3 Pressure Regulator for Differential Oil Supply Pressure
Because i-series compressor is the fully differential pressure oil supply type, it is necessary to
secure the minimum oil supply pressure (oil supply pressure – suction pressure).
Similarly to the case of single packages, install the pressure regulator at the outlet side of the oil
separator.
In case of Figure app.2-1 multi-package, instrument piping is attached from the suction side.
When the number of compressors to be controlled, connect the instrument piping for the pressure
regulator to the suction gas common header. If the instrument piping is connected to the suction
side of each compressor, the pressure condition becomes instable when the compressor is
stopped.
2-2-4 Oil Cooler
Similarly to the case of single package, selecting either one from the water cooled type,
high-pressure liquid type, and liquid injection type is possible for the oil cooler of multi-package.
When the water cooled type or the high pressure liquid type is used, the oil cooler can be shared.
However, if the liquid infection type is used, place the oil cooler at locations, at which each
supplying oil to the compressor can be cooled.
In cold districts, where the minimum temperature of supplying oil cannot be kept, install the oil
heater to the oil separator and mount the oil temperature control valve to the oil supply line (Refer
to Appendix 1 Section 1-3
"Oil Temperature Control").
2-2-5 Oil Filter and Oil Line
Be sure to install the oil filter less than 20 μm (β20≥150) filtration precision to each compressor in
order to protect the compressors (refer to Section 3.2.5.2 in this manual Chapter 3).
For the multi-package, each oil supply piping to the oil filter after oil cooler should be connected
from common oil header so as to be uniform lubrication.
The flow in Figure app.2-1 has drawn in prerequisite that number of compressors is to be
controlled. Therefore, the motor valve is provided after the oil filter, so the oil does not flow back
when the compressor is stopped. Do not select a valve that can be operated in a back pressure.
2-2-6 Stop Valve and Safety Valves
The flow in Figure app.2-1 is an example of multi-package. Install the stop valves for the
maintenance purpose according to the applicable regulations and as necessary. At that time,
install the safety valves appropriately to the piping, heat exchanger, and the tanks carefully
according to the applicable regulations.
Methods to select the appropriate safety valves are different depending on the local applicable
laws and design guidelines.
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