For fluid dynamics parameters, media properties of check valve performance relationship in China, in order to promote the drill string check valve research theory and technology progress.

寻求流体动力学参数、介质性质对止回阀性能的影响关系，以推进我国钻柱止回阀研究理论和技术进步。

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Inside the riser pipe is a space about half a meter in diameter, large enough to hold the spinning drill pipe and bit and to allow the return flow of drilling fluid.

FORBES: The delicate art of sucking up