Engineering manual - SAB 193-233-283 S A-frame (including ATEX)
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008831 en 2020.10
Easy to operate
UniSAB III has a systematic and easily accessible user interface which does not require any spe-
cial knowledge or education.
Operational data and status appear from the distinct display which features four lines with twenty
characters each. The user interface has arrow keys for menu selection, set key for parameter
changing and keys for selection of start/stop and resetting. Manual/automatic operation and
manual capacity regulation is performed with function keys.
Safety monitoring and control
UniSAB III provides safe monitoring by means of shutdown and alarm values/settings for all
measuring points. If a set value is exceeded, a red diode will flash slowly in alarm situations with-
out stopping the compressor and quickly in shutdown situations. A display text will show the
cause of the alarm or shutdown. In both alarm and shutdown situations separate relays are acti-
vated for connection of a remote lamp, bell or alarm panel.
It is easy to find all the set values and their alarm and shutdown values through the straightfor-
ward menu system.
Besides monitoring the compressor pressures and temperatures, UniSAB III also calculates the
suction pressure vapour overheating, monitors the capacity slide position and oil flow and calcu-
lates the oil filter differential pressure on screw compressors and SMC reciprocating compressors.
For correct fault diagnosis in case of compressor shutdown, UniSAB III immediately stores all
shutdown situations in its memory which can be displayed and analysed on the display at any
time.
Instrumentation
Depending on the compressor type, UniSAB III is equipped with a number of pressure and tem-
perature transducers as well as position transmitters on the compressor.
Screw compressors are fitted with four pressure transducers and three temperature transducers
as well as one or two slide position transmitters.
Furthermore, a thermistor input is available for motor protection.
Factory test
Every UniSAB III is tested during the production process and when it is mounted on the compres-
sor. A computer test is performed before the compressor leaves the factory.
For further information, see separate UniSAB III manual.
4.5
Compressor
The compressor is equipped with an integral suction strainer placed in the transversely suction
side “cylinder like cavity” with access from the side on top of the compressor block. The filter pre-
vents impurities in the gas from entering and damaging the compressor.
The suction stop valve, 101, is bolted to the suction side flange with a non-return valve, 129, in
between. The non-return valve prevents the compressor from rotating backwards during a stand-
still period or shutdown.
The discharge gas is sent via the discharge line to the oil separator (193). Gas on the discharge
side of the compressor is mixed with a relatively large amount of oil injected into the compressor
for lubrication, cooling and tightening. The oil and the gas must be separated before the discharge
gas proceeds into the refrigeration plant.
Summary of Contents for Sabroe SAB 193 L
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