Chapter 2
Compressor Specifications and Structure
UD-series Screw Compressors
2.3
Compressor Specifications
2-5
2.3.2 Operation Limits
Table 2-4 Operation Limits of UD-series Screw Compressors
I t e m
O p e r a t i o n L i m i t
Maximum discharge pressure
MPa
1.96 (Other than 320LL, 400LL, 400XL)
1.37
（
320LL,400LL,
）
0.60
（
400XL
）
Maximum suction pressure
MPa
0.59
Minimum suction pressure
MPa
-0.080
Minimum differential pressure
between discharge pressure and
suction pressure
MPa
0.49
Maximum oil supply pressure
MPa
Forced oil supply
Pd + 0.39
Minimum oil supply pressure
MPa
Forced oil supply
Pd + 0.049
Maximum suction temperature
°C
85
Minimum suction temperature
°C
-60
Maximum discharge temperature
°C
90
Maximum oil supply temperature
°C
60
Minimum oil supply temperature
°C
30
Maximum M rotor rotation speed
min
-1
4500 (320*UD, 400*UD are 3600)
Minimum M rotor rotation speed
min
-1
1450
Applications
NH
3
, R134a, R404A, R507A
Propane, propylene, CO2
R407C, R407F, R410A, as same as J and gas
compressor for other gases
Note 1: Unless otherwise noted, the pressure unit MPa represents the gauge pressure in this manual.
Note 2: The oil supply pressure of the capacity control part (control hydraulic pressure of the unloader
slide valve), the value of the forced oil supply pressure is applied.
Note 3: When it is required that pressure difference between Pd (discharge pressure) and Ps (suction
pressure) should be not greater than 0.49 MPa, oil pump needs to be installed.
If a combination of "NH
3
+ compatible oil (PN46)" is used for working fluid (refrigerant) and
lubricating oil, oil pump must be installed.
Note 4: Please contact us when using it for gas pressure.
