发明授权
US3589667A Combination well blowout preventer 失效
组合良好的防喷器

Combination well blowout preventer
摘要:
The disclosure concerns unusually advantageous apparatus used in controlling and preventing well blowouts, and utilizing novel plug-valve sealing and operating structure, and further as related to the location and housing of an inwardly constrictable packer annulus.
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