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The Difference Between Rising Stem Gate Valve and Non-rising Stem Gate Valve?

16 Aug.,2023

Gate valve has the characteristics of small fluid resistance, wide range of applicable pressure and temperature, and is the most commonly used cut-off valve, used for cutting off or connecting the medium in the pipeline.

Rising stem gate valve

Rising stem gate valve: the valve stem nut is on the valve cover or support, when opening and closing the gate, use the rotating valve stem nut to realize the up and down movement of the valve stem. This structure is beneficial to the lubrication of the valve stem, and the opening and closing degree is obvious, so it is widely used.

Usually there is a trapezoidal thread on the lifting rod, through the nut at the top of the valve and the guide groove on the valve body, the rotating motion is converted into linear motion, that is, the operating torque is converted into operating thrust. The opening and closing part of the rising stem gate valve is the gate, and the direction of gate movement is perpendicular to the direction of fluid flow. The rising stem gate valve can only be fully opened or fully closed, and cannot be adjusted or throttled.

Non-rising stem gate valve

The non-rising stemindustrial gate valve is also called the rotating stem gate valve (also called non-rising stem wedge gate valve). The valve stem nut is inside the valve body and is directly in contact with the medium. The rotation of the valve stem is used to open and close the gate. The opening and closing part of the non-rising stem gate valve is the gate, and the direction of gate movement is perpendicular to the direction of fluid flow. The gate valve can only be fully opened or fully closed, and cannot be adjusted or throttled. The valve stem nut is located on the gate, and the handwheel drives the valve stem to rotate, and the gate is lifted. Usually there is a trapezoidal thread at the bottom of the valve stem, which converts the rotating motion into linear motion through the thread at the bottom of the valve and the guide groove on the valve disc, that is, the operating torque is converted into operating thrust.

Main differences between rising stem gate valve and non-rising stem gate valve

The lifting screw of the non-rising stem gate valve only rotates without upward and downward movement. The only visible thing is a rod, and the nut is fixed on the gate to lift the gate by rotating the screw. There is no visible gate frame; the lifting screw of the rising stem gate valve is exposed, and the nut is tightly attached to the handwheel and is fixed (neither rotating nor axially moving). The gate is lifted by rotating the screw. The screw and the gate have only relative rotational motion and no relative axial displacement, and the appearance is a gate-shaped support.
The screw of the non-rising stem gate valve is not visible, while that of the rising stem gate valve is visible.
The non-rising stem gate valve connects the steering wheel and the valve stem together without relative motion when opening and closing. It is driven by the rotation of the valve stem at a fixed point to lift and lower the valve disc to complete the opening and closing. The rising stem gate valve lifts or lowers the valve disc through the threaded transmission between the valve stem and the steering wheel. To put it simply, the gate and the valve stem of the rising stem gate valve move up and down together, and the steering wheel is always fixed at a fixed point.