Hi,

For Control valve,

whether, a Axial stop should be provided at the exit of the control valve. Is it mandatory ?.

regards,
bvk

No, why would you ask this question, it's an odd question.

bvk,

The typical size control valve with 10% pressure drop would not have a significant thrust load from the pressure drop across the valve. Usually the thrust forces are in equilibrium from the other ends of piping (elbows, tees, closures). It would be an over-simplification to compare it to the thrust unbalance of a piping reducer - do you ever see an axial stop at reducers?

There are exceptions. The high pressure steam line to a turbine could have a trip & throttle valve. A sudden shutdown from 'trip' event could result in a 'steam hammer' impulse load which has been observed to move the piping more than a few inches. An axial stop (perhaps with small gap for normal expansion movement) would be recommended. Other control valves with potential high thrust should also be evaluated for impulse loads. A pressure relief valve is the more common example of impulse loads.

The question disconnects unbalnced forces (hammer) types of loads from their source, and asks about (ALL) control valves alone.... This is why this is an oddity. Its as though EVERY control valve should be given a stop???? There must be some very interesting design in some parts of the world!

Some Control valves can cause turbulence in the downstream piping which can lead to piping vibration. So some clients/companies recommend "anchors" . But this is usually prudent for large pressure reductions and/or high flow rates.

For folks who have been to the field, the majority of control valves require nothing extra, but we have all been by the noisy ones and I have put my hand on these and they do shake. Food for thought.