Gate jet preventing device for drilling well

The utility model relates to a flashboard blowout preventer used for a well drilling, relating to a control device used for a petroleum well drilling, which belongs to an appurtenance used for the petroleum well drilling. The board blowout preventer mainly solves the problems that the sealing is not reliable and the operation is not convenient, the weight of the flashboard blowout preventer is lighter, and the bearing capacity is bigger. The flashboard blowout preventer consists mainly of a casing, a flashboard, a side gate, liquid cylinders, and cylinder covers. The utility model is characterized in that the cross section of the flashboard cavity in the casing is of a long-round shape, an arc sealing strip and a front sealing strip are arranged on the flashboard, the end parts of the curved sealing strip and the front sealing strip are overlapped, through holes are arranged in the open and the close piston rods arranged in the two cylinders, an oil valve is arranged in the hydraulic oil channel in the cylinder cover, a sealing rack is arranged between the side gate and the casing, a through groove is arranged on the sealing rack, three seal rings are arranged on the sealing rack, the hydraulic pressure is utilized to open or close the side gate, the operation is convenient, the flashboard blowout preventer is mainly used for the petroleum well drilling project.