A process fluid lubricated pump for conveying a process fluid is proposed, comprising a pump housing (2) with an inlet (21) for receiving the process fluid having a suction pressure, and an outlet (22) for discharging the process fluid having a discharge pressure, a pump shaft (5) extending from a drive end (51) to a non-drive end (52) of the pump shaft (5) and configured for rotating about an axial direction (A), wherein the drive end (51) of the pump shaft (5) is arranged outside the pump housing (2), the pump further comprising a hydraulic unit (3) with a plurality of impellers (31, 32, 33) fixedly mounted on the pump shaft (5), a collection chamber (23) for collecting leaking process fluid, wherein the collection chamber (23) comprises a shaft exit (24), through which the pump shaft (5) passes from the inside to the outside of the pump housing (2), and a fluid exit (25) for discharging the process fluid from the collection chamber (23), wherein the pump is designed as a seal-less pump without a mechanical seal, wherein a throttle device (6) is arranged with respect to the axial direction (A) between the hydraulic unit (3) and the collection chamber (23), wherein the throttle device (6) comprises a stationary throttle part(61) having a first axial face (611) and a second axial face (612) delimiting the stationary part (61) with respect to the axial direction (A), wherein the first axial face (611) faces the collection chamber (23), and wherein the throttle device (6) comprises a throttle gap (62) surrounding the pump shaft (5) and extending from the first axial face (611) to the second axial face (612) for allowing a leakage of the process fluid along the pump shaft (5) into the collection chamber (23). Furthermore, a pump system comprising such a pump (1) is proposed,