I would like to ask the experts: what causes the valve stem to bend?
Thread Content
I would like to ask the experts: what causes the valve stem to bend? Medium used: fire water, operating pressure 0.6 Mpa
The quality of the valve stem may not meet the pressure requirements; it could be due to the high impact force of fluid flow when the gate valve is opened to a small degree； After all, it has a working pressure of 0.6 MPa.
The quality of the valve is the main factor; working pressure plays a minor role
The diameter of the valve stem does not meet the requirements specified in the design standards, right?
Is it a problem with the material of the valve stem? Then an external force brought it there.
It may be that external forces caused the valve stem to bend, for example, when the valve was closed to its final position, an F wrench was used to apply additional force. Another suggestion: if the valve does not need to be opened and closed frequently, it is best to install it vertically.
This situation generally shouldn’t occur with valves in normal use. If it’s caused by the valve being closed too far, then what amount of force would be required! Someone must have used the valve stem as an anchor point to lift something.
It must be due to external forces; the quality of the valve is also a factor... There have been cases where a DN100 gate frame was broken using a wrench as well
It’s possible that too much force was applied; another reason is that the valve stem itself is too long, and due to lack of use over time it deforms under the effect of gravity. This is similar to the bending of the shafts in horizontal pump units, and it’s necessary to turn the shaft regularly
If valve opening and fluid flow changes do not occur when the valve is of good quality, another possibility is that debris has blocked the valve channel, and excessive force is applied when closing the valve, resulting in bending of the valve stem