What is the difference between a rising stem gate valve and a non rising stem gate valve?
date:2023-10-23 14:21
1. The lead screw cannot be seen in the concealed valve, while the lead screw can be seen in the exposed valve.
2. The lifting screw of the non rising flange gate valve only rotates without moving up and down, and only one rod is exposed. Its nut is fixed on the gate plate, and the gate plate is lifted by the rotation of the screw, without a visible gate frame; The lifting screw of the rising stem flange gate valve is exposed, and the nut is tightly attached to the handwheel and fixed (not rotating or axially moving). The gate is lifted by rotating the screw. The screw and gate only have relative rotational motion without relative axial displacement, and the appearance is a door-shaped bracket.
3. When a non rising valve is opened or closed, the steering wheel and valve stem are connected together and relatively stationary. It is achieved by rotating the valve stem at a fixed point to drive the valve disc up and down to complete the opening and closing. Rising stem valves raise or lower the valve disc through a threaded transmission between the valve stem and steering wheel. Simply put, a rising stem valve is a valve disc that moves up and down together with the valve stem, and the steering wheel is always at a fixed point. Turn left | turn right
Difference between rising stem and non rising stem gate valves
The advantages of rising stem gate valves are:
The fluid resistance is small, and the sealing surface is less susceptible to medium erosion and erosion.
Opening and closing are more effortless.
The flow direction of the medium is unrestricted, does not disturb flow, and does not reduce pressure.
Simple form, short structural length, good manufacturing process, and wide application range.
The disadvantages of rising stem gate valves are:
The sealing surfaces are prone to erosion and scratches, making maintenance difficult.
The overall size is relatively large, requiring a certain amount of space for opening and closing, and the opening and closing time is long.
Complex structure
The advantages of a non rising stem gate valve are:
The height of the gate valve remains constant, so the installation space is small, 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.
4. The disadvantages of non rising stem gate valves are:
The valve stem thread not only cannot be lubricated, but also directly accepts medium erosion and is prone to damage
