A process fluid lubricated pump for conveying a process fluid, having a common housing, a pump unit arranged in the common housing, and a drive unit arranged in the common housing, wherein the common housing comprises a low pressure inlet and a high pressure outlet for the process fluid, wherein the pump unit comprises a pump shaft extending from a drive end to a non-drive end of the pump shaft and configured for rotating about an axial direction, the pump unit further comprising a first pump section having a first set of impellers fixedly mounted on the pump shaft and configured for increasing the pressure of the process fluid, wherein the drive unit is configured to exert a torque on the drive end of the pump shaft for driving the rotation of the pump shaft, wherein a first balance drum is fixedly connected to the pump shaft between the pump unit and the drive end of the pump shaft, the first balance drum defining a first front side facing the pump unit and a first back side, wherein a first relief passage is provided between the first balance drum and a first stationary part configured to be stationary with respect to the common housing, the first relief passage extending from the first front side to the first back side, characterized in that a second balance drum is fixedly connected to the pump shaft between the pump unit and the non-drive end of the pump shaft, the second balance drum defining a second front side facing the pump unit and a second back side, wherein a second relief passage is provided between the second balance drum and a second stationary part configured to be stationary with respect to the common housing, the second relief passage extending from the second front side to the second back side, and wherein a balance line is provided connecting the first back side and the second back side. wherein the common housing comprises a low pressure inlet and a high pressure outlet for the process fluid, wherein the pump unit comprises a pump shaft extending from a drive end to a non-drive end of the pump shaft and configured for rotating about an axial direction, the pump unit further comprising a first pump section having a first set of impellers fixedly mounted on the pump shaft and configured for increasing the pressure of the process fluid, wherein the drive unit is configured to exert a torque on the drive end of the pump shaft for driving the rotation of the pump shaft, wherein a first balance drum is fixedly connected to the pump shaft between the pump unit and the drive end of the pump shaft, the first balance drum defining a first front side facing the pump unit and a first back side, wherein a first relief passage is provided between the first balance drum and a first stationary part configured to be stationary with respect to the common housing, the first relief passage extending from the first front side to the first back side, characterized in that a second balance drum is fixedly connected to the pump shaft between the pump unit and the non-drive end of the pump shaft, the second balance drum defining a second front side facing the pump unit and a second back side, wherein a second relief passage is provided between the second balance drum and a second stationary part configured to be stationary with respect to the common housing, the second relief passage extending from the second front side to the second back side, and wherein a balance line is provided connecting the first back side and the second back side.