Abstract: There is disclosed a ram type blowout preventer in which the chambers in which the rams are received and for movement between opened and closed positions are automatically vented to the bore of the preventer housing above the closed rams, as the rams are moved to open position, in order to equalize pressure across the ram and thus facilitate its opening. When the rams are moved to closed position, this vent is closed so that well pressure beneath the closed rams has access through a groove between the ram and the ram chamber to the chamber behind the closed rams so as to assist operating fluid in maintaining them closed. The stem which connects a piston of a hydraulic system for operating the rams is hollow and so arranged as to be pressure balanced whereby there is substantially no force due to well fluid pressure resisting closing movement of the rams due to the extension of the rod sealably through an opening in a wall separating the ram chamber from the cylinder of the hydraulic system.

Abstract: There is disclosed a ram type blowout preventer in which the chambers in which the rams are received and for movement between opened and closed positions are automatically vented to the bore of the preventer housing above the closed rams, as the rams are moved to open position, in order to equalize pressure across the ram and thus facilitate its opening. When the rams are moved to closed position, this vent is closed so that well pressure beneath the closed rams has access through a groove between the ram and the ram chamber to the chamber behind the closed rams so as to assist operating fluid in maintaining them closed. The stem which connects a piston of a hydraulic system for operating the rams is hollow and so arranged as to be pressure balanced whereby there is substantially no force due to well fluid pressure resisting closing movement of the rams due to the extension of the rod sealably through an opening in a wall separating the ram chamber from the cylinder of the hydraulic system.

Abstract: There is disclosed a blowout preventer having rams with cutting edges for shearing a pipe within the vertical bore through the preventer housing which rams carry means for gripping opposite sides of the pipe above the cutting edges of the rams, as the rams move toward one another to shear the pipe, and lifting the upper sheared end of the gripped pipe out of the path of means for sealing between the inner ends of the rams, as the rams continue to move toward one another.

Abstract: There is disclosed a ram-type blowout preventer having shear rams and fluid operated actuators for the shear rams which are of such construction as to move the rams inwardly to shear a pipe with a first, relatively large force, and then further inwardly to close the rams with a second, relatively small force, and which also includes locking elements adapted to be moved into positions locking the rams in closed positions automatically in response to inward movement of the rams to closed positions following shearing of the pipe.

Abstract: There is disclosed a blowout preventer having rams with cutting edges for shearing a pipe within the vertical bore through the preventer housing which rams carry means for gripping opposite sides of the pipe above the cutting edges of the rams, as the rams move toward one another to shear the pipe, and lifting the upper sheared end of the gripped pipe out of the path of means for sealing between the inner ends of the rams, as the rams continue to move toward one another.

Abstract: There is disclosed a blowout preventer having rams each of which is moved between opened and closed positions by a fluid-operated actuator having a rod adapted to be axially reciprocated by piston means within a cylinder and extending from the cylinder for connection to the ram, means for locking the rams in closed position including locking elements carried by the rod for movement into locking position within the cylinder automatically in response to movement of the ram with the rod into closed position.

Abstract: There is disclosed a blowout preventer having rams with cutting edges for shearing a pipe within which carry means for gripping opposite sides of the pipe above the cutting edges of the rams, as the rams move toward one another to shear the pipe, and lifting the upper sheared end of the gripped pipe out of the path of means for sealing between the inner ends of the rams, as the rams continue to move toward one another.