A cut-off valve merit A, simple structure, manufacture and maintenance more convenient. B, the working stroke is small, open and close a relatively short time (the height of the valve opening and closing is typically only 30% of its nominal diameter of). C, sealing, small friction force between the sealing surface, longer life expectancy (Figure). Second, the disadvantage A, a large fluid resistance, the larger the force required to open and close. B, does not apply with particles, viscosity, easy to crystallize the media. C, adjusted poor. Absolutely can not do with the regulation and control. Condition: gate valve sealing performance ratio better suited to the smaller diameter pipe, but the structure is longer than the length of the valve, the valve is slightly lower than the overall manufacturing costs. Third, the thermal insulation globe valve shut-off valve (BJ41W) is mainly used in petroleum, chemical, metallurgy, pharmaceutical and other types of systems to transport will be solidified at room temperature high viscosity media, the system of valves in the valve jacket welding between two flanges, the side of the valve, the bottom of the jacket provided by the connection port, due to the increased jacket, valve size than the connecting flange is connected to the two flanges freshman same specifications common specifications shut-off valve, but length of the structure is the same with the same specifications valves, the jacket can flow freely through the medium of steam or other thermal insulation, ensuring smooth viscous media can flow through the valve.