For this kind of trunnion ball valve, Wosheng employs the piston-type fixed ball valve structure to enhance its resistance to pipe stress. The stem is designed with blow-out proof structure and replaceable stem sealing system. The bi-directional dual-seal mechanism ensures an excellent sealing effect, and the bi-directional quadruple structure has largely added to the reliability of the sealing system. With the sewage hole mounted on the valve bottom, the valve can run efficiently and safely. It is applied in underground pipelines, pipeline branches, water supply system, heating system, fluid shut-off control, etc.