Process fluid lubricated pump and pumping system

A process fluid lubricated pump for conveying a process fluid, comprising:

• a pump housing with an inlet configured to receive the process fluid having a suction pressure, and an outlet configured to discharge the process fluid having a discharge pressure;
• a pump shaft extending from a drive end to a non-drive end of the pump shaft and configured to rotate about an axial direction, the drive end of the pump shaft arranged outside the pump housing;
• a hydraulic unit with a plurality of impellers fixedly mounted on the pump shaft;
• a collection chamber configured to be at ambient pressure and to collect leaking process fluid, the collection chamber comprising a shaft exit, through which the pump shaft passes from the inside to the outside of the pump housing, and a fluid exit configured to discharge the process fluid from the collection chamber,
• the pump being a seal-less pump without a mechanical seal, and a throttle device arranged with respect to the axial direction between the hydraulic unit and the collection chamber, the throttle device comprising a stationary throttle part having a first axial face and a second axial face delimiting the stationary throttle part with respect to the axial direction, the first axial face facing the collection chamber, and the throttle device comprising a throttle gap surrounding the pump shaft and extending from the first axial face to the second axial face to enable a leakage of the process fluid along the pump shaft into the collection chamber.