... ,2FZ2835,2FZ 2870, 2FZ3535, ZFZ3570 and 2FZ5414 ram blowout preventer: double ram blowout preventerstype:2FZ1835, 2FZ1870,2FZ2835,2FZ 2870, ... 35CrMo OR 25CrNiMo3)working pressure: 2000PSI--15000PSI A blowout preventer is a large, specialized valve used to seal, control ... to cope with extreme erratic pressures and uncontrolled flow emanating from a well reservoir during drilling ram blowout preventer