| 摘要 |
A ram-type blowout preventer having a housing with a vertical bore, aligned ram guideways extending outward from opposite sides of the bore, a ram in each guideway, means for moving the rams inward and outward in the guideways to open and close on a drill or pipe string in the bore, a packer in each ram having a packing with an upper slotted plate thereon and a lower slotted plate therebelow, the plates being sufficiently flexible to move into close proximity to a string when the rams are closed thereon to support the packing against extrusion.
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