The crank-chain driving and long stroke pumping unit described in this papes is a new type of pumping unit.

曲柄链条动滑轮式长冲程抽油机是一种新型抽油机。

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The crank-chain driving and long stroke pumping unit described in this papes is a new type of pumping unit.

曲柄链条动滑轮式长冲程抽油机是一种新型抽油机。

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