The handwheel drives the valve stem nut to rotate. When the nut rotates, the valve stem moves up and down. The valve stem does not turn. There is a groove on the side of the gate, and a guide boss on the inner wall of the valve body. The two cooperate with each other to guide and restrict the gate. The gate is attached to the T-head at the end of the stem.
Gate valves are one of the most widely used valves on the market. According to the type, it can be divided into rising stem gate valve and non rising stem gate valve. Let's talk about the working principle, advantages and disadvantages of the two and the difference in use. Lifting rod gate valve, commonly used models are Z41H-10, Z41H-16 and so on. Working principle: The valve stem of the gate valve drives the gate to move up and down, the valve stem is outside the valve body, the driving thread of the valve stem can be seen, and the opening and closing and position of the gate can be seen. Judging intuitively according to the movement direction and position of the valve stem.
When the rising stem gate valve is opened, it can be seen that the valve stem gradually rises. The opening of the gate valve can be judged by the rise of the valve stem, and whether the valve is open or closed can be judged by the position of the valve stem. Therefore, in important occasions, rising stem gate valves are often used to prevent misjudgment when problems occur.
1.The lifting screw of the flange gate valve only rotates and does not move up and down. Only one rod is exposed, and its nut is attached to the door. The gate is lifted by the rotation of the screw, and the gantry cannot be seen. ;The lifting screw of the rising rod flange gate valve is exposed, and the nut is close to the handwheel and fixed (not rotating or moving axially). Lift the gate by rotating the screw. There is no relative axial displacement, and the appearance is a portal bracket.
2.The lead screw cannot be seen in the rising stem gate valve, and the lead screw can be seen in the rising stem valve.
3.When the gate valve is switched on and off, the steering wheel and the valve stem are connected together and are relatively static.
Through the fixed-point rotating valve stem, the valve disc lift gate is driven to complete the opening and closing. The rising stem gate valve raises or lowers the disc through the threaded transmission of the valve stem and the steering wheel. In simple terms, a rising stem gate valve is a valve disc, which is connected to the valve stem and moves up and down together, and the steering wheel is always at a fixed point. When the dark stem gate valve is opened, the valve stem only rotates and does not move up and down. The opening and closing state of the gate valve cannot be seen from the outside, because the appearance does not change during the opening and closing process, unlike the rising and falling process of the stem gate valve. Therefore, in important occasions, a valve stem indicator will be installed on its appearance to distinguish the valve switching state. Concealed stem gate valves are suitable for applications where space is limited because their height does not change when opened. The medium in the pipeline should be clean, and impurities will cause the valve stem and gate thread to be stuck, resulting in the failure of the switch. The stem and gate threads are corroded by the medium, and the service life is not as good as that of the open stem gate valve.