The balls of the floating ball valves are floating. Under the action of the medium pressure, the balls can produce a certain displacement and press tightly on the sealing surface of the outlet end to ensure that the outlet end is sealed. The floating ball valves have a simple structure and good sealing performance, but the load of the working medium on the sphere is all transmitted to the outlet sealing ring. Therefore, it is necessary to consider whether the material of the sealing ring can withstand the working load of the sphere medium. When subjected to a higher pressure impact, the sphere may shift. This structure is generally used for medium and low pressure ball valves. Floating ball valves are suitable for general industrial use.
The balls of the ball valves are fixed and do not move after being pressed. Fixed ball valves are equipped with a floating seat. After being pressured by the medium, the seat will move so that the sealing ring is pressed tightly on the sphere to ensure sealing. Bearings are usually installed on the upper and lower shafts of the sphere, 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 valves and increase the reliability of the seal, oil-sealed ball valves have appeared in recent years, that is, special lubricating oil is injected between the sealing surfaces to form an oil film, which not only enhances the sealing performance, but also reduces the operating torque. It is more suitable for high-pressure and large-caliber ball valves.
The balls of the orbital ball valves are elastic. Both the ball and the valve seat sealing ring are made of metal materials, and the sealing specific pressure is very large. The pressure of the medium itself cannot meet the sealing requirements, and external force must be applied. This valve is suitable for high temperature and high pressure media.
The elastic sphere is made by opening an elastic groove on the lower end of the inner wall of the sphere to obtain elasticity. When closing the passage, use the wedge-shaped head of the valve stem to expand the ball and press the valve seat to seal. Loosen the wedge-shaped head before rotating the sphere, and the sphere will return to its original shape, so that there is a small gap between the sphere and the valve seat, which can reduce the friction of the sealing surface and the operating torque.
The V ball valve is fixed ball valve and also single-seat sealed ball valve. The adjustment performance is the best among ball valves, the flow characteristics are equal percentages, and the adjustable ratio is up to 100:1. It has a shearing effect between its V-shaped incision and the metal valve seat, which is especially suitable for media containing fibers, small solid particles, slurry and other media.
Three-way ball valves have T type and L type. The T type can connect three orthogonal pipelines with each other and cut off the third channel, which can split and merge. The L-shape can only connect two orthogonal pipes, and cannot maintain the third pipe to communicate with each other at the same time. It only plays a distribution role.