Patent ID: 7530391
Filing Date: 2009-05-12
Classification: E21B,F04D

Abstract:
1. A seal section for a submersible well pump assembly, comprising: a housing for connection between a pump and a motor of a submersible well pump assembly; a rotatable shaft extending through housing for transmitting rotational motion from the motor to the pump; a central radial bearing support that rotatably supports the shaft and which defines upper and lower chambers in the housing; a well fluid passageway leading from an exterior portion of the housing to the upper chamber; upper and lower isolation tubes extending around the shaft within the upper and lower chambers, respectively, each of the isolation tubes having an inner diameter larger than the shaft, defining an annular passage for fluid communication with lubricant contained in the motor; a bladder surrounding the upper isolation tube in the upper chamber for separating lubricant within the bladder from well fluid in the upper chamber on the exterior of the bladder; and a labyrinth tube within the bladder and having an upper end in fluid communication with a labyrinth port leading through the upper isolation tube near its upper end to the annular passage, the labyrinth tube having a lower end in fluid communication with the lower chamber.