The sealing is good, but the load of the working medium on the sphere is transmitted to the outlet sealing ring, so it is necessary to consider whether the material of the sealing ring can withstand the working load of the sphere medium, and the sphere may shift when subjected to high pressure impact. This structure is generally used for medium and low pressure ball valves.

The ball of the ball valve is fixed and does not move after being pressurized. Fixed ball and ball valves are equipped with floating valve seats. After being subjected to medium pressure, the valve seat moves, so that the sealing ring is pressed tightly on the ball to ensure the sealing. Usually, bearings are installed on the upper and lower shafts with the ball, 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 the seal, an oil-sealed ball valve has appeared, which not only injects special lubricating oil between the sealing surfaces to form an oil film, which enhances the sealing performance, but also reduces the operating torque. Suitable for high pressure and large diameter ball valves.