The BOP has a single gate and dual gate in two forms, usually on the plant silk, under the flange forms (which can be designed according to user requirements), mainly from the shell, side door, cylinder, cylinder head, piston, piston rod, lock shaft, sealing parts, ram, etc., and its working principle is: high-pressure oil into the cylinder closed cavity around, the push piston, piston rod, so that left and right gate assembly along the guide bar gate to the wellhead interior Centre mobile. When contact between left and right gate, the gate assembly in the external force, the rubber seal was to play the role of extrusion to achieve the purpose of pumping wells; when the high pressure oil into the cylinder about to open chamber, the left and right gate assembly to move the center from wellhead to achieve the purpose of opening.