Engineering manual - SAB 193-233-283 S A-frame (including ATEX)
008831 en 2020.10
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Fig. 34: System with open valve
4.27
Oil cooling system and general piping layout
General:
Min. oil temperature before start-up: 4°C (+40°F)
Min. oil temperature in running condition: 20°C (+68°F)
Liquid injection oil cooling:
The compressor oil is cooled by direct contact with the refrigerant
injected through an optimised port location prior to the compressor discharge. Liquid feed ar-
rangements include isolation valves, strainer, solenoid valve, sight glass, a thermal expansion
temperature control valve and a pressure differential control valve. The temperature control
valve will maintain the temperature of the oil returning to the compressor between 54.4°C [130°
F] and 76.7°C [170°F].
Water-cooled oil cooling:
The optional water-cooled oil cooler is either a plate and shell design
(Vahterus) with oil on the plate side or a plate type oil cooler (AlfaNova). The coolers are designed
for design pressure 28 bar on both sides. The oil temperature is maintained between 50°C [120°
F] and 60°C [140°F] for ammonia and halocarbons with a thermally controlled valve. The oil cool-
er is mounted on the unit with the oil piping connected. Water connections and controls are field
installed.
Thermosyphon oil cooling:
The optional thermosyphon cooler is a plate and shell design (Vah-
terus) or a plate type oil cooler (AlfaNova). It is designed for design pressure 28 bar on the shell
side and 28 bar on the plate side. The oil coolers are mounted on the unit with the oil piping con-
nected. Refrigerant connections and controls are field installed. The oil temperature is maintained
between 50°C [120°F] and 60°C [140°F].
4.28
Liquid injection oil cooling
High-stage compressor units may be supplied with single-port (low Vi) or dual-port (low Vi and
high Vi) liquid injection oil cooling. Single port will be furnished for low compression ratio opera-
tion and dual port for high compression ratio operation. Booster compressor units use single-port
liquid injection oil cooling due to the typically lower compression ratios.
The control system on high-stage units with dual-port liquid injection oil cooling automatically
switches the liquid refrigerant supply to the high port when the compressor is operating at higher
compression ratios (above 3.5 Vi) for best efficiency.
Where low compression ratios are anticipated, thermosyphon or water-cooled oil cooling should
be used.
Oil separator, condenser
Condensing pressure
Compressor
Evaporating
pressure
P
0
1
P
2
”
P
1
P
1
P
1
P
2
Summary of Contents for Sabroe SAB 193 L
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