Patent ID: 6357552
Filing Date: 2002-03-19
Classification: E21B,F04B,F04C

Abstract:
A submersible pump assembly for downhole use, comprising a gear transmission (10) which comprises a transmission housing (12) filled with lubricating fluid, an input shaft (14) adapted to be driven, at least one transmission step (22) to reduce the rotational speed of the input shaft (14, 102, 120), an output shaft (16) for driving a pump, and at least one equalizer (24) for adaptation of the lubricating fluid pressure in the transmission housing (12) to ambient pressure, wherein the equalizer (24) is arranged within the transmission housing (12) next to the transmission step (22) and incorporated in a lubricating fluid circuit and at least one pump means (60, 62; 156, 158) causes the lubricating fluid in the transmission step (22) and in the equalizer (24) to flow in axial direction of the transmission step (22), a first pump means (60, 62) and a second pump means (156, 158) each are arranged in axially outer end regions (81, 163) of the input (14) and output (16) shafts, respectively, to each convey the lubricating fluid axially inwardly towards the middle so that two opposed flows (A, B) will result.