| 摘要 |
The appliance for lowering and cementation of drive pipe comprises a body, throttle and shutoff assembles. The body comprises two branch pipes and muff, those fix the shutoff assembly as conical pair, and the throttle assembly has openings placed in the plate of the back valve, coaxiality of those with the openings of the saddle of the valve is provided by installation of the pin in the saddle of the valve and in the opening in the plate of the valve.
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