Oil-injected multi-stage compressor system and procedure for controlling such a compressor system

A procedure controlling an oil-injected multi-stage compressor system (1) comprising at least a low-pressure stage compressor element (2) with an inlet (4a) and an outlet (5a) and a high-pressure stage compressor element (3) with an inlet (4b) and an outlet (5b), whereby the outlet (5a) of the low-pressure stage compressor element (2) is connected to the inlet (4b) of the high-pressure stage compressor element (3) through a pipeline (6), wherein the compressor elements (2, 3) are provided with their own drive in the form of an electric motor (2a, 3a), whereby the compressor elements (2, 3) are connected either directly or by a gearbox to the electric motor (2a, 3a) and that an intercooler (9) is installed in the above pipeline (6) between the low-pressure stage compressor element (2) and the high-pressure stage compressor element (3), whereby this intercooler (9) is adjustable, whereby the compressor system (1) is also provided with a control unit or regulator (11) for controlling or regulating the intercooler (9) so that the temperature at the inlet (4b) of the high-pressure stage compressor element (3) is above the dew point, and that the procedure comprises the following steps:

• calculating or determining the dew point at the inlet (4b) of the high-pressure stage compressor element (3);
• and
• additionally regulating the intercooler (9) so that the temperature at the inlet (4b) of the high-pressure stage compressor element (3) is above the dew point by at least partly bypassing the intercooler (9).