Johnson Controls SABROE ComPAC, Operating Manual

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Operating manual - ComPAC
011769 en 2020.03
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Design and function
3.2.8 Automatic oil recovery system from evaporator
The relatively small amount of oil leaving the compressor and oil separator with the discharge gas
is gradually collected at the bottom of the evaporator.
An oil recovery pot, Fig. 16, is connected to the evaporator by a pipe. From the recovery pot, the
oil is automatically returned to the compressor.
A float is fitted in the oil recovery pot, pos. 9, Fig. 15. It has the exact density which allows it to
float on the collected oil and sink in R717.
The float has a built-in reed switch which activates the solenoid valve, pos. 8 in Fig. 15, in the oil
return line to the compressor and the solenoid valve, pos. 7 in Fig. 15, on the hot gas line. The oil
is led directly to the compressor suction side, driven by the pressure difference between the LP
and HP sides.
The oil pot has an integrated piston which is driven by the discharge gas. The piston closes the
connection to the evaporator during the oil recovery cycle.
Fig. 15: System for screw compressor
Pos. no. Component
1 Compressor
2 Evaporator
3 Level float switch
4
Stop valve
5 Stop valve
6 Stop valve
7
Solenoid valve combined with filter and stop function
8 Solenoid valve combined with filter and stop function
9
Oil recovery pot
10 Discharge gas line