Blowout preventers are commonly used in oil fields to close the wellhead during operations such as well testing, workover, and completion to prevent blowout accidents. They integrate the functions of full sealing and semi sealing, and have the characteristics of simple structure, easy operation, and high pressure resistance. They are a safe sealing wellhead device commonly used to prevent blowout. A blowout device installed on the wellhead casing head during oil drilling to control high-pressure oil, gas, and water. When the oil and gas pressure in the well is very high, the blowout preventer can seal the wellhead (shut it down). When heavy mud is pressed into the drill pipe, there is a four way joint under the ram, which can replace the mud that has been invaded by gas and increase the pressure of the liquid column in the well to suppress the high-pressure oil and gas injection.