blind ram

1. n. [Drilling]
A thick, heavy steel component of a conventional ram blowout preventer. In a normal pipe ram, the two blocks of steel that meet in the center of the wellbore to seal the well have a hole (one-half of the hole on each piece) through which the pipe fits. The blind ram has no space for pipe and is instead blanked off in order to be able to close over a well that does not contain a drillstring. It may be loosely thought of as the sliding gate on a gate valve.