The sealing performance is good, but the load of the working medium borne by the sphere is all transferred to the outlet sealing ring. Therefore, it is necessary to consider whether the sealing ring material can withstand the working load of the sphere medium. When impacted by high pressure, the sphere may shift. This structure is generally used for medium and low pressure ball valves.
The ball of the ball valve is fixed and does not move under pressure. All fixed ball valves are equipped with floating valve seats. After the medium pressure, the valve seats will move, making the seal ring tightly pressed on the ball to ensure sealing. Generally, the upper and lower shafts of the ball are equipped with bearings, and the operating torque is small, which is suitable for high-pressure and large-diameter valves.
In order to reduce the operating torque of the ball valve and increase the reliability of sealing, an oil sealed ball valve has also appeared. It not only injects special lubricating oil between the sealing surfaces to form an oil film, which not only enhances the sealing performance, but also reduces the operating torque, and is more suitable for high pressure and large caliber ball valves.
