Abstract: An annular preventer blowout preventer (BOP) that can seal off a wellbore for controlling and monitoring oil and gas wells. The BOP is a latch type annular preventer with a body, a inner, a piston, and a rubber packing element. The preventer seals around drill pipe and in some instances against an open well bore. A plurality of latches and inner screws secure the lid to the body and further prevent rotation.

Abstract: A detector that monitors the presence of halogenated agents and the presence of N2O includes a base to which a filter cannister is removably coupled. The cannister has an input for accepting exhalent from a patient or an anesthesia machine and an outlet for outputting the filtered exhalent as gases to the base. The filtered gases are routed a gas measurement or monitor cell housed in the base. The cell has a halogenated agents sensing system and a N2O sensing system. When the filter material in the filter cannister could no longer filter out the halogenated agents, the agents are passed from the filter to the measuring cell, which would detect the presence of the halogenated agents. An audible alarm sounds when halogenated agents are detected. This tells the user that it is time to replace the filter cannister.