3.13
[en] 02/2014
Installation and operating manual - NK 31
A
Minimum pressure valve closed
B
Minimum pressure valve opened
C
Minimum pressure valve opened, non-return
valve closed
1. Non-return valve plate
2. Non-return valve spring
3. O-ring
4. Pressure holding valve piston
5. Pressure holding valve spring
6. Pressure holding valve housing
7. Spacing washer
A
B
C
2
3
4
5
6
7
1
Figure 3-12
The minimum pressure valve is located on the
outlet of the compressor before the air recooler
and serves as:
A Pressure holding valve
It prevents the pressure drop, in case of a lack
of counter-pressure, under a minimum pressure
of approx. 5.5 bar. This pressure is necessary to
ensure the oil supply of the compressor. At the
same time this is the condition for good oil sepa-
ration.
C Non-return valve
It prevents compressed air from flowing back out
of the system or the compressed-air reservoir
into the screw compressor system. As a result,
the system can be completely discharged when
the separator reservoir is switched off.
This valve operates automatically.
3.11.3 Minimum pressure valve
