Valve stem buckling 1

[theminimalist00]

Hi all!

Does anyone know how to prevent knife gate valves stems from buckling ?

Thanks

 

[btrueblood]

Make them thicker.

 

[bcd]

Make them shorter.
Reduce the force.
Make them bigger in diameter.
Install a guide bearing in the middle.

 

[gerhardl]

?????
See the answers above, valid under all conditions.

When does the problem occur? At valve construction stage? In operating? At the valve stem itself or for extended/prolonged stems? Motor or hand operated?

A normal knifegate stem at the valve itself will not buckle unless you use forces far above normal closing force. This might occur if you try to force the valve shut if something is hindering a full closure. This is usually debris, clogging, or for a badly constructed valve also dirt or dry stuff collecting in corners or edges not constructed self-cleaning. A highly weared valve might also give problems.

A knifegatevalve is also sometimes used for very difficult 'fluids' with a high content of dry stuff, or at high temperatures, and will get stuck by debris sticking on the blade. Problems will increase by valve used or mounted wrongly, for instance horizontally in stead of vertical, bearing weight of pipeline or other skew forces.

All problems will increase if the valve is operated by an extended stem.

Forces might be controlled by instructions for correct hand operating forces or by el. actuators with correctly adjusted torque and endstop devices.