... cameron 3. According to :API Spec 16A Blow-out preventer(BOP) The BOP has a single gate and dual gate in two forms ... (which can be designed according to user requirements), mainly from the shell, side door, cylinder, cylinder head, piston, piston rod, lock ... between left and right gate, the gate assembly in the external force, the rubber seal was to play the role of extrusion to achieve ...