在这方面引擎蒸汽进入对一方一偏心转子，载有轧辊对密封的内套管。
In this engine the steam enters on one side of an eccentric rotor which carries rollers that seal against the inside of the casing.
套管偏心是影响顶替效率的关键因素。
The casing offcenter is a key factor to effect the displacing efficiency.
井架不正或井口偏心，会造成近井口套管（或套管防磨套）的磨损。
Both the derrick deviation and the wellhead's eccentricity will cause the serious wearing of the casing (or casing protecting tube) close to the wellhead.
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