Engineering manual - SMC/TSMC/HPC 100 Mk 4 LL & Mk 5 and HPX 700 Mk 4 LL & Mk 5
010294 en 2021.12 7/375
4.7 Oil return to the compressor........................................................ 74
4.7.1 Solenoid valve controlled oil return ....................................... 74
4.7.2 Oil return in connection with parallel operation ......................75
4.8 Capacity regulation of the compressor, SMC/HPC 100..................79
4.8.1 Capacity regulation and unloading of the compressor ............ 79
4.8.2 Mechanism of capacity regulation system .............................79
4.8.3 Unloaded compressor start.................................................. 81
4.8.4 Solenoid valves for capacity regulation .................................81
4.8.5 "Standard unloading" capacity regulation.............................. 82
4.8.6 "Total unloading" capacity regulation ....................................84
4.8.7 "Extended unloading" capacity regulation .............................85
4.8.8 Variable speed drive (VSD).................................................. 88
4.9 Capacity regulation of the compressor, HPX 700 .......................... 90
4.9.1 Capacity regulation and unloading of the compressor ............ 90
4.9.2 Mechanism of capacity regulation system .............................90
4.9.3 Unloaded compressor start.................................................. 91
4.9.4 Solenoid valves for capacity regulation .................................91
4.9.5 “Standard unloading” capacity regulation .............................. 92
4.9.6 “Total unloading” capacity regulation ....................................93
4.9.7 Variable speed drive (VSD).................................................. 94
4.10 Compressor unit ........................................................................95
4.11 Instrumentation.......................................................................... 97
4.11.1 Analogue reading and safety system ....................................97
4.11.2 UniSAB III reading, safety and capacity regulating
system ............................................................................. 100
4.12 Cooling of the intermediate discharge gas on TSMC
compressors............................................................................ 101
4.12.1 Intermediate cooling system with intermediate cooler type
DVEA, R717..................................................................... 101
4.12.2 Intermediate cooling system with liquid injection into the in-
termediate discharge gas, R22 and R717 ........................... 102
4.12.3 Automatic regulation of intermediate pressure IP................. 103
4.12.4 Determining the intermediate pressure, IP .......................... 104
4.13 Cooling systems for compressors.............................................. 105
4.13.1 Air-cooled top and side covers with refrigerant-cooled oil
cooler R717 (1a)............................................................... 105
4.13.2 Water-cooled top and side covers - R717 (1b)..................... 107
4.13.3 Cooling with thermopump - R717 (1c)................................. 115
4.13.4 Air-cooled top and side covers - R22, R134a, R404A,
R507 (2a)......................................................................... 124
4.13.5 Air-cooled top covers and water-cooled side covers -
R717, R22, R134a, R404A, R507 (1d + 2b) ........................ 124
4.13.6 Air-cooled top and side covers and refrigerant-cooled oil
cooler
R22, R134a, R404A, R507 (2c).......................................... 124