aparelho, método para a manutenção de uma pressão e sistema

Systems and methods for maintaining a desired differential pressure between a cooling oil of an electric motor and a process gas working fluid of a compressor connected axially to the electric motor. The cooling oil acts as a coolant for the motor compartment of the electric motor and the gas working fluid acts as a coolant for the rotor compartment of the electric motor. At least one bellow is configured to provide two sealed compartments in a pressure equalizer and a spring means is configured to add a differential pressure to the cooling oil, assuring no leaks between the two fluids flows from the cooling oil to the process gas working fluid and no contact of the process gas working fluid with the electric motor stator, in particular electric motor laminations and electric motor windings.