The pipeline fixed ball valve Q347F of Product Overview: pipeline valve for ANSI Class 150 ~ 900, -28 ~ 300 ℃ working temperature piping of various conditions such as petroleum, chemical, fire station, cut off or connected media. Applicable medium: oil, natural gas purification, acid gas, gas, water and coal slurry, etc. medium. The mode of operation: manual, worm gear, pneumatic, electric, gas-liquid interaction. Product structural features: a stagnant medium of the valve in the cavity due to temperature changes and abnormal pressure, medium pressure to promote seat out of the sphere, to achieve the effect of automatic pressure relief, pressure relief valve seat is automatically reset. When the event of a fire or the seat ring burning or softening due to abnormal temperature rise, the valve operation is still reliable, the same time, the valve seat and ball to form a metal-to-metal contact, and temporarily sealed to prevent the fire further expand line with APIFA provisions. Unscrew the excretion of device check valve seat leak occurs, also can be discharged media in cavity retentate reduce pollution to the valve. In working condition, the valve is fully open or fully closed, replace the stuffing box of the valve stem. 4 seat in addition to general sealing, special settings the auxiliary for sealing structure, can play emergency ambulance role leak due to damage to the seal ring. The stem parts sealed using of PTFR filler and 0-ring, particularly applicable to the gas medium. The stem moving parts using high-quality SF smaller self-lubricating bearings, the friction system to reduce operating torque.