1. Non rising stem gate valve: The stem nut is located inside the valve body and in direct contact with the medium. When opening and closing the gate, rotate the valve stem to achieve this. The advantage of this structure is that the height of the gate valve remains constant, so the installation space is small, making it suitable for gate valves with large diameters or limited installation space. This structure should be equipped with an opening and closing indicator to indicate the degree of opening and closing. The disadvantage of this structure is that the valve stem thread not only cannot be lubricated, but also directly accepts medium erosion, which is easy to damage.

2. Rising stem gate valve: The valve stem nut is located on the valve cover or bracket. When opening and closing the gate, rotate the valve stem nut to achieve the lifting and lowering of the valve stem. This structure is beneficial for the lubrication of the valve stem and has a clear degree of opening and closing, so it is widely used.

3. The lifting screw of the non-rising stem gate valve only rotates without moving up and down. What is exposed is only a rod, and its nut is fixed on the gate, which is lifted by the rotation of the screw, without a visible gantry. The lifting screw of the rising stem gate valve is exposed, and the nut is tightly attached to the handwheel and fixed (not rotating or axially moving). Lift the gate by rotating the screw. The screw and the gate only have relative rotational motion without relative axial displacement, and have a door shaped support in appearance.

4. The non-rising stem gate valve cannot see the screw, while the exposed valve can see the screw.

The steering wheel and valve stem are connected together and remain relatively stationary when the non-rising stem gate valve is opened and closed. It is achieved by rotating the valve stem at a fixed point to drive the valve disc up and down to complete opening and closing.

The rising stem gate valve is lifted or lowered by the threaded transmission between the valve stem and the steering wheel.