Difference between rising stem gate valve and Non

Hall of knowledge: the difference between rising stem gate valve and Non rising stem gate valve

gate valve can be divided into:

1 rising stem gate valve: the stem nut is on the bonnet or bracket. When opening and closing the gate valve, rotate the stem 3 Display abnormal information to realize the lifting and lowering of the valve rod. This structure is beneficial to the lubrication of the valve rod, and the opening and closing degree is obvious, so it is widely used

2 Non rising stem gate valve: the valve stem nut is in the valve body and is in direct contact with the medium. When opening and closing the ram, rotate the valve rod. The advantage of this structure is that the height of the gate valve always remains the same, so the installation space is small. It is suitable for gate valves with large diameter or limited installation space. This structure should be equipped with an opening and closing indicator to indicate the opening and closing degree. The disadvantage of this structure is that the valve rod thread is not only unable to be lubricated, but also easily damaged if it is directly eroded by the medium if the oil is improperly used

main differences:

1 The lifting screw of the Non rising stem flange gate valve only rotates without moving up and down. Only one rod is exposed, and its nut is fixed on the ram. The ram is lifted through the rotation of the screw, and there is no visible gantry; The lifting screw of the rising stem flange gate valve is exposed, and the nut is close to the handwheel and is fixed (neither rotating nor axially moving). You can independently seek its business goal to rotate the screw to lift the ram. The screw and the ram only have relative rotating movement without relative axial displacement, and the appearance is a gate shaped support

2 for the first time, the Non rising stem valve came into contact with some composite reports and databases in the United States, but the lead screw could not be seen, while the rising stem valve could see the lead screw

3. When the Non rising stem valve is opened and closed, the steering wheel and the valve rod are connected together and relatively immobile. It is through the rotation of the valve rod at the fixed point to drive the valve disc to lift up and lower to complete the opening and closing. The rising stem valve lifts or lowers the valve disc through the threaded transmission between the valve stem and the steering wheel

to put it simply, the rising stem valve moves up and down with the valve disc and the valve stem, and the steering wheel is always at the fixed point