KAESER CSD 75, Service Manual, Page: 17 / 81

Construction and Operation
5 --- 12
5 Construction and Operation
5.1 Principle of Compression
The stationary compressor package is fitted with a single stage, oil---injected airend. The
two rotors, the driven male rotor and the female rotor, both mounted in antifriction bear-
ings, are fitted into the airend. As the rotors rotate, air is drawn into the upper side through
the inlet port and is compressed on the lower side. The oil that is injected into the lower
side absorbs heat generated by compression, prevents metal to metal contact between
the rotors, seals the rotors and the housing from each other and also lubricates the antifric-
tion bearings. The compressed air and oil mixture leaves the airend via the discharge port.
1 2 3
6
4 5
1 Drive shaft 4 Male rotor
2 Oil injection 5 Female rotor
3 Discharge port 6 Air inlet port
5.2 Brief Description
The compressor block is driven by an electric motor via a coupling.
An oil separator cartridge is fitted into the oil separator tank allowing practically oil free
compressed air supply.
The control system of the compressor unit ensures that compressed air is generated within
the set pressure limits.
Safety devices protect the compressor unit against failure of important systems through
automatic shut ---down.
The fan ensures sufficient cooling air flow to the air ---cooled oil cooler and air aftercooler.