Curtis OL 512 - Manual (Page 22)

CAP-215
9
Instruction Manual Oil-Less Compressors
2-stage compressor
The position stated refer to Fig. 3.
The two first stages (5) of the oil-less compressor draw in the outside air via the intake filter (14) and the crankcase and
compressed to an intermediate pressure of approx. 60 to 70 psi. The compressed air is cooled back to the original
temperature in the intermediate coolers (3) and is then lead to a manifold (10). The intermediate pressure safety valve (2)
mounted at this manifold is adjusted to a pressure of 120 psi. The condensate is filtered out in the intermediate separator
(7) and is lead to the condensate drain valve (15)(option),The 2nd stage compresses the air now to a final pressure of
max. 210 psi. (Dependent on adjusted operation pressure).
A non-return valve (Fig. 6) is built into the condensate
drain line of the intermediate separator.
It prevents an equalization of pressure between
1st and 2nd stage during the condensate drain.
After opening the solenoid valve the separator of
the 2nd stage is drained. The separator of the 1st
stage is drained after an equalization of pressure
between 1st and 2nd stage.
Fig 8: Function of non-return valve