Stem Deformation Causes:
Stem is mainly able to be compressed, can be well insulated, and is not easy to decay and rust, it has the sealing function of both sides, more durable to wear, and its service life is longer. Then there are several reasons why the stem will break or deform:
1. Area
The stem usually breaks at the bottom of its upper and lower threads, because the area is relatively small, which is prone to force concentration and beyond the standard.
2. Fracture occurs at opening
Generally speaking, the most likely rupture of the stem occurs at the moment of opening. The main reason is that the gate has not been separated from the seat and the stem is broken at the root of the upper or lower threads. Generally, it is considered that the gate is stuck. This is not the whole reason, nor is it the most important one.
3. Valve body
The abnormal temperature rise and pressure drop occur after the middle chamber of the valve body is closed, that is to say, when the valve is closed, the fluid pressure in the middle chamber between the upper and lower sealing surfaces is much higher than the upstream pressure. The reasons are as follows:
(1) Expansion
(2) The fluid pressure in the middle chamber between enclosures is much higher than that in the upstream. The reasons are as follows:
(1) Expansion
(2) Closure
