Control valves
Figure 6. Severe buffeting in an LNG application was limiting site production and damaging the valve. The condition was resolved by adding an inlet grid seat ring to break up the flow eddies and strengthening the valve stem and actuator. Courtesy of Emerson.
shortening valve service life, and requiring more frequent maintenance. After studying and modeling the application, the valve vendor identified the condition and suggested a number of changes to the existing control valve( Figure 6). A grid seat ring was installed on the trim inlet to eliminate the flow eddy and straighten flow through the valve. The valve stem and actuator were also strengthened to minimise resonance and damp any remaining vibrations. The results were immediate and significant. Despite the slight obstruction, the grid ring actually increased valve capacity by eliminating the flow recirculation and smoothing fluid flow. Additionally, the reduced FIV and stiffer valve components dramatically improved valve positioning performance since the erratic pressure fluctuations and stem movement of the original valve were virtually eliminated( Figure 7). The net result was a multimillion-dollar cost avoidance for the customer by avoiding modifications to existing piping systems, with site production increased and maintenance outages eliminated.
Conclusion
Noise and vibration associated with a control valve installation can have a variety of causes. If left untreated, these conditions can create valve damage, and they can even crack pipe welds in extreme situations. The first step to address the problem is careful investigation of the valve installation and adjacent piping to fully
understand the source of the vibration. Often the frequency of the vibration can provide a clue, and advanced fluid dynamic modeling techniques can be utilized to fully identify the cause and investigate potential solutions. When faced with a vexing valve noise or vibration problem, it may be helpful to engage your control valve vendor. With ready access to advanced modeling tools and laboratory fluid labs, which can study and replicate the condition, the vendor can help end users understand the situation and identify the cause. Armed with that knowledge, the solution is usually straightforward, and it may involve simple piping modifications or changes to the control valve internal components. Extreme vibration and noise associated with control valves can be problematic, but elimination is possible once the source is identified.
About the authors Thirumalai Karthik( TK) Arasu is a global industry sales manager for severe service with Emerson. He has 17 years of application experience, specialising in anti-cavitation, anti-noise, and highperformance engineered control valves. Arasu holds a Bachelor of Engineering degree in Electronics and Instrumentation from the National Engineering College in India.
Chris Vergos is a severe service sales engineer with Emerson. He has 12 years of experience providing application support for various industrial markets such as oil and gas and power generation. Chris holds a Bachelor’ s degree in Chemical Engineering from the University of Pittsburgh.
Figure 7. Erratic actuator pressure fluctuations( left) were virtually eliminated once the LNG valve modifications were installed. Valve positioning precision was dramatically improved, and site capacity was increased. Courtesy of Emerson.
28 Valve World February 2026 www. valve-world. net