Ball valves are widely used in industrial automation in the production of pipeline media fluid cutoff. It has a simple structure, small size, fast opening and closing, good sealing performance and other advantages. Ball valves are generally divided into two categories: floating ball valves and fixed ball valves.

Floating Ball Valve

Floating ball valve through the import and export of the two seats, clamping the middle ball core, rotating the valve stem to drive the ball core to rotate 90 ° to achieve the switching action of the ball valve. Ball core in the closing, the valve stem top semicircular and ball core semicircular groove direction, in the media pressure, the ball core can be moved to the export direction, so it is called floating ball. It is commonly used valve seat materials are PTFE, RPTFE, PPL nylon, PEEK, metal, etc.. Floating ball valve inlet and outlet seats have a certain sealing preload, wrapped around the ball core. When the valve is closed, the medium pushes the ball core to tighten the back seat, thus ensuring the sealing of the ball valve. However, this will greatly increase the valve's switching action load, if the valve front pressure is too high or large caliber, the load of the rear seat at this time is greater than the seat material allows the pressure. The rear seat may be damaged, or the sealing surface is crushed. So the floating ball valve is generally suitable for low temperature, low pressure and small diameter occasions.

Fixed ball valve

Fixed ball valves have two seats, one at the inlet and one at the outlet, and use springs or disc springs to provide preload for them so that the seats are tightly attached to the ball spool. The ball core is positioned by the upper and lower valve stems, and the valve opening and closing can be realized by turning the upper valve stem. When the valve is closed, the ball spool is held in place by the upper and lower stems so as not to increase the rear seat load. Before and after the valve seat in the media pressure so that the valve seat close to the ball core to achieve the effect of double sealing before and after the valve seat. It is commonly used in high temperature, high pressure and large diameter occasions.