GEA Grasso V Series Installation And Maintenance Instructions Manual

General limits and fields of operationREFRIGERANT NH3Design pressure PSs *19 Grasso V(T) -26.5 bar(a)This pressure deviates from the socalled max. dischargepressure=condensing pressure(allowed during operation) as statedin the table.Discharge temperature teGrasso V max.+170 °CThis is the actual dischargetemperature, measured directly inthe gas flow just before thedischarge connection. The givenvalue also applies to the LP stageof two-stage compressors.Discharge temperature LP Grasso VTPressure ratio per stage (pc/poor pc/pm or pm/po)Pressure ratio limits are notabsolute but arbitrary valuesbased on practicalconsiderationsj -min. 1.5max. 10Pressure difference delta-pGrasso V300(T) .. 600(T) max.(pc - po) <= 25.5 barThe standard built-in overflowsafety valve(s)(pc - pambient) <= 25.5 barGrasso V700(T) ..1800(T)max.(pc - po) <= 19.0 barThe standard built-in overflowsafety valve(s)(pc - pambient) <= 25.5 barOil temperature in crankcase toil °Cmin.>10oC and > Tsaturated crankcasepressure at stand still + 15 KIndicated minimum value is thelowest oil temperature at which thecompressor is allowed to be started.max.< 70 oC, depending on type of oilThe maximum oil temperaturedepends on the operatingconditions of the compressor andthe oil type used.A minimum actual oil viscosity of 10cSt in the bearings is alwaysrequired.4.3 STARTING UP OF TWO-STAGE COMPRESSORSProcedure for starting from compressor standstillIn the case of two-stage compressors it is very important that immediately afterthe period of automatic fully unloaded start (ensured by the corresponding three-way solenoid valve in the control pressure supply line from the oil pump; only oneor more H.P. cylinders become operative, viz. only those cylinders of which thesuction valve lifting mechanism is directly and permanently connected to the19 “PSs“ is mentioned on type plate of the compressor (Possibly "Pd" is mentioned for compressorsdelivered before 1-Mar-2013)APPENDIX; Product Information (PI)STARTING UP OF TWO-STAGE COMPRESSORS0089288gbr_1152 30.10.2017