The opening and closing member of the shut-off valve is a plug-shaped valve flap, the sealing surface is flat or tapered, and the valve flap moves linearly along the center line of the valve seat. The movement form of the valve stem (general name: dark rod), also has the lifting rotary rod type, (common name: bright rod) the stop valve refers to the valve that the closing member (valve) moves along the center line of the valve seat. Depending on the form of movement of the flap, the change in the seat opening is proportional to the flap travel. Due to the relatively short opening or closing stroke of the valve stem of this type of valve, and the very reliable cutting function, and because the change of the valve seat opening is proportional to the stroke of the valve flap, it is very suitable for the adjustment of the flow rate. Therefore, this type of shut-off globe valve is well suited for shut-off or regulation and throttling.
The shut-off valve, also called the door, is the most widely used type of valve. It is popular because it has a small friction between the sealing surfaces during the opening and closing process, is relatively durable, and has a small opening height and is easy to manufacture. Easy to maintain, not only for medium and low pressure, but also for high pressure.
The closing principle of the shut-off valve is that, relying on the pressure of the valve bar, the sealing surface of the valve disc and the sealing surface of the valve seat are closely fitted to prevent the medium from flowing.
The shut-off valve allows only one-way flow of the medium and is directional when installed. The structural length of the shut-off valve is larger than that of the gate valve, and the fluid resistance is large. When the machine is operated for a long time, the sealing reliability is not strong.