Have you all used bidirectionally sealed trunnion ball valves?

　　Ball valves come in two types: floating ball valves and fixed ball valves. The so-called double-port ball valve is another name for a fixed ball valve. 　　In the closed position of a floating ball valve, the valve core is pushed, by the pressure of the medium upstream, against the seal that is located downstream; the greater the pressure, the tighter the seal ； 　　The valve core of a fixed ball valve is equipped with a shaft (ear); in the closed position, the position of the valve core remains unchanged, and the seal element presses against the valve core through elasticity to achieve sealing – which places certain demands on the design and material of the seal element. 　　Floating ball valves are easy to seal, but they may experience high resistance when opening and closing ； Fixed ball valves operate smoothly, but require high standards for sealing. 　　For two-way ball valves, the floating structure imposes higher requirements on seals due to the need for a specific gap between the floats ； The fixed structure does not impose significant increases in technical requirements. 　　It’s hard to say which type of structure is better; however, most ones available on the market are floating ball valves, while fixed ball valves are usually found in high-end products.