摘要 |
A progressive cavity pump is used as part of the production string in an oil well. A pump stator is coupled to the production tubing string, while the rotor is driven by a sucker rod. To ensure proper placement of the rotor in the stator, the rotor is driven by a drive shaft with two universal joints with the upper end of the drive shaft held in position by a thrust bearing on the drive shaft and engaging a bearing seat connected to the production tubing. This ensures proper vertical placement of rotor in the stator. It also prevents eccentric motion of the upper end of the drive shaft, so that the sucker rod is no longer subject to whipping action that may damage the production tubing and the sucker rod string.
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