Abnormal noise from the stop valve

Check if the valve stem and valve core have fallen off

Is the connection between the valve core and the valve stem loose or detached?

What is the form of the abnormal noise sound? Is it the sound of metal? Is it fluid resonance again? Or some other sound? Because, under normal circumstances, when a globe valve is opened to a small degree, the flow velocity of the fluid at the constriction increases, which may lead to phenomena such as cavitation and flashing. Or at low opening degrees, the flow velocity is high, resulting in resonant noises from the valve internals and similar issues. All of them could be the unusual noises mentioned by the poster. . In my opinion, it is quite easy to identify and resolve the issue of loose valve internals. If it’s not a loosening issue, as a temporary solution, you can try removing the internal valve first and machining away a thin layer from the part responsible for its function, in order to change the resonance frequency and see if that helps. Or, if conditions permit, reverse the valve installation and see the effect. In the long run, it’s best to choose a different model. Choose an air erosion-resistant valve type, or a noise-reducing valve.