Pipe shearing ram assembly for blowout preventer

Claim 2

A blowout preventer comprising a body having a pipe opening therethrough, ram guideways extending laterally from opposite sides of the pipe opening, a ram assembly comprising fIrst and second rams, each located in one of the ram guideways, and means for moving the rams together to close off the pipe opening and for moving the rams apart to open the pipe opening, each ram having a knife blade attached thereto in position for the cutting edge of the blade on one ram to pass just below the cutting edge of the blade on the other to shear any pipe positioned in the pipe opening when the rams are moved together to close off the opening, and seal means on each ram positioned to engage and be compressed by the knife blade on the other ram when the rams engage to form a separate and independent seal between the knife blade on each ram and the seal means on the other.

Claim 3

The blowout preventer of claim 1 in which the cutting edge of each knife blade is generally concave, tapering inwardly from each side toward the center, to cause the blades to tend to center the pipe between the blades as the rams are moved together and to shear the pipe progressively from the sides toward the middle of the blades as the rams are moved together.

Claim 4

A ram assembly for positioning in ram guideways that extend laterally from opposite sides of a pipe opening in the body of a blowout preventer, comprising two rams for movement between an engaged position closing off such pipe opening to a spaced apart position opening such pipe opening to receive pipe, said rams having oppositely facing surfaces that engage when the rams close off the pipe opening, each said ram having a knife blade extending laterally across said surface with its cutting edge projecting therefrom, said blades being positioned on the rams for the cutting edge of one blade to pass just below the cutting edge of the other blade, when the rams are moved together through their respective ram guideways, to shear pipe positioned in the pipe opening, and seal means on the rams to seal off the pipe opening when the rams are in engagement, said seal means including a seal member extending laterally across the facing side surface of each ram to be compressed by the knife blade on the other ram as the rams move into engagement.

Claim 5

A ram assembly for positioning in ram guideways that extend laterally from opposite sides of a pipe opening in the body of a blowout preventer, comprising two rams for movement between an engaged position closing off such pipe opening to a spaced apart position opening such pipe opening to receive pipe, said rams having oppositely facing surfaces that engage when the rams close off the pipe opening, each said ram having a knife blade extending laterally across said surface with its cutting edge projecting therefrom, said blades being positioned on the rams for the cutting edge of one blade to pass just below the cutting edge of the other blade, when the rams are moved together through their respective ram guideways, to shear pipe positioned in the pipe opening, and seal means on the rams to seal off the pipe opening when the rams are in engagement, said seal means including a seal member extending laterally across the facing side surface of each ram to be compressed by the knife blade on the other ram as the rams move into engagement.

Claim 6

The ram assembly of claim 3 in which the knife blades taper inwardly toward the center thereof to tend to center pipe positioned between them and to shear the pipe progressively inwardly toward the center of the cutting edge as the rams are moved together.