According to the structure of the valve stem, the gate valve can be divided into Rising Stem Gate Valve and Non Rising Stem Gate Valve.

1. Rising Stem Gate Valve: The valve stem nut is on the bonnet or bracket. When opening and closing the wedge, you can rotate the valve rod nut to realize the lifting and lowering of the valve rod. This structure is beneficial to the lubrication of the valve rod, it has obvious opening and closing degree, and is widely used.

2. Non Rising Stem Gate Valve: The valve stem nut is in direct contact with the medium in the valve body. Rotate the valve rod to open and close the wedge. The advantages of this structure are: the height of the gate valve remains unchanged and the installation space is small. The disadvantages are: the valve rod thread cannot be lubricated, and it is directly eroded by the medium, which is easy to be damaged.

Difference between the TWO:

1. The lifting screw of the Non rising stem gate valve only rotates without moving up and down. Only the valve stem head is exposed, its nut is fixed on the wedge. The wedge is lifted by rotating the screw;

    The lifting screw of the rising stem gate valve is exposed. The nut is close to the hand wheel and fixed. The wedge is lifted by rotating the screw. The screw and the wedge only have relative rotary motion without relative axial displacement.

2. The Non rising stem gate valve can’t see the lead screw;

    The rising stem gate valve can see the lead screw.

3. When the Non rising stem gate valve is opened and closed, the steering wheel and the valve stem are connected together and relatively immobile. It completes the opening and closing by the rotation of the valve rod at the fixed point drives the valve disc to lift and lower;

    The rising stem gate valve lifts or lowers the disc through the threaded drive between the valve stem and the steering wheel.