19 20 21 from these containers the air is then conveyed further to various parts of the vehicle for being used for different needs as illustrated in fig1 two of the containers 19 and 21 are intended for compressed air to be used in the brake system of the vehicle two wheel brakes 22 and 23 are disclosed schematically if so desired the suspension emulsion which leaves the centrifugal separator 8 may be supplied to a special liquid separator not disclosed which is arranged to separate the oil from the water and possible solid particles if the oil is of the same kind as the lubrication oil in the combustion engine 2 it may continuously or batchwise be supplied to the lubricating system of the combustion engine while the water and possible particles are collected in the container 11 the oil separation proper may be performed intermittently or continuously during the operation of the compressor for the oil separation a so called static lamella separator for instance located in the container 11 or a small centrifugal separator of any kind may be used the centrifugal separator 8 mentioned above for relieving compressed air from particles is schematically disclosed in a longitudinal section in fig2 the centrifugal separator 8 includes a stationary non rotatable housing 24 the above mentioned conduit 6 via which compressed and cooled air is supplied from the cooler.