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The difference between rising stem and non-rising stem gate valve
- Apr 26, 2018 -

According to the structure of the stem, gate valve can be divided into:

1. Rising stem valve: When the valve stem nut is on the valve cover or bracket and the shutter is opened and closed, the valve stem can be raised and lowered by rotating the stem nut. This kind of structure is beneficial to the lubrication of the valve stem, and its opening and closing is obvious, so it is widely used.
2.Non-rising stem valve: The stem nut is in the valve body and is in direct contact with the medium. When opening and closing the gate, use a rotary valve stem. The advantage of this structure is that the height of the gate valve always remains the same, so the installation space is small and it is suitable for large diameter or gate valves with limited installation space. This structure should be equipped with open and close indicators to indicate the degree of opening and closing. The disadvantage of this structure is that the stem thread not only cannot be lubricated, but also directly accepts media erosion and is easily damaged.

The main difference between rising stem and non-rising stem gate valves:

1. The lifting rod of the non-rising gate valve is rotated only without moving up and down. The exposed stem is just a stem. The nut is fixed on the gate plate. The gate is lifted by the rotation of the screw. There is no visible mast. The lifting screw of the rising stem gate valve is exposed. The nut is close to the handwheel and is fixed (without rotation or axial movement). By rotating the screw to lift the gate, the screw and the gate only have relative rotational motion. No relative axial displacement, the appearance of a gate bracket.

2. The non-rising stem valve cannot see the screw, while the rising stem valve can see the screw.

3. When the non-rising stem valve is on and off, the steering wheel and the valve stem are connected and relatively unmovable. It is through the valve stem rotating at a fixed point to drive the valve flap to lift upwards and close the gate to complete the opening and closing. The rising stem valve is used to raise or lower the valve plate through the thread of the valve stem and the steering wheel. The simple point is that the valve is connected to the valve stem with the valve stem up and down movement, the steering wheel is always at a fixed point.