توپ ثابت استشیر توپی is fixed and is supported by two fixed shafts connected with the ball. When closed, the ball will not be displaced under the action of the medium pressure. Usually, the upper and lower shafts connected with the ball are equipped with rolling bearings or sliding bearings. In order to reduce the friction of the journal when opening and closing. Reduce the operating torque. This fixed شیر توپی is suitable for large-caliber شیر توپیs. The ball of the hard-seal fixed شیر توپی is fixed by two upper and lower stems. When working, the fluid pressure will not make the ball move to the valve seat, and the valve seat will not be deformed due to excessive pressure. The valve stem part is equipped with self-lubricating bearings to reduce friction, the switch torque is small, and the two valve seats are pre-tightened by springs. The seal is made of PTFE inlaid into the steel, and the back of the steel ring is equipped with a spring to ensure that the valve seat is close to the sphere. When the pressure in the valve cavity rises abnormally and exceeds the spring tightening force, the valve seat retreats from the sphere to achieve the effect of automatic pressure relief, and the valve seat automatically resets after pressure. The advanced structure of the fixed شیر توپی makes the sealing performance of the fixed شیر توپیپایدار ، صرفه جویی در کار و عمر طولانی ، که برای خطوط لوله از راه دور و خطوط لوله عمومی بسیار مناسب است.