Detecting Valve Seat Leaks

The devices that touch your process such as control valves, measurement instrumentation, and analyzers have tremendous impact on the ability to control the process efficiently. Even the best control and advanced control strategies can’t do what they are designed to do if the input measurements are inaccurate or the control valves are not responding as they should.

One example is leaky valve seats. A leaky valve, depending on where it located in the process, can impact reliability, efficiency, and quality. I caught up with Emerson’s Damon Meadows, a member of the Instrument & Valve Services team. Damon shared with me that their team has been working with a leading researcher and manufacturer of acoustic emission technologies as a technology provider for a Valve Seat Leak Detection service offering in North America.

This diagnostic service is non-intrusive and non-disruptive to valve operation and works with the other diagnostic applications including ValveLink, FlowScanner, and AMS Device Manager software.

Control valve seat leakThe valve seat leak diagnostics can check pressurized valves, which are required to remain closed during inspection. The technology is based upon Valve-Squeak acoustical emissions technology for qualitative through-valve loss detection and the VPAC II for leak rate quantification. The Instrument & Valve Services’ technicians use these diagnostic tools to measure internal valve seat leaks to detect a leak’s acoustic emission. This method of “listening” to the sounds of valve seat leakage permits separation of leakage signals from high ambient background noise, increasing leak rate quantification accuracy.

These diagnostics provide estimated valve seat leakage to aid in making better decisions in prioritizing maintenance, repair or replacement of valves during plant turnaround planning. This service is performed typically during pre-turnaround walk-downs and for post-turnaround verification. Other valve lifecycle services include diagnostics, open inspect and OEM certified repair, and replacement of Fisher control valves.

As we’ve highlighted in prior posts, detailed turnaround planning is critical to the effectiveness of the time the plant is shutdown.

Having this critical diagnostic information available during the planning stages of a turnaround is an important tool that gives plant staff greater flexibility to narrow or expand turnaround scopes. Additional testing is underway in the Emerson Innovation Center Flowlab, the world’s largest valve test facility, to enhance this technology when applied to advanced Fisher valve geometries.

Damon noted that the Valve Seat Leak Detection service helps to focus maintenance attention on the valves that have the greatest impact on plant reliability, efficiency, quality, and profitability.

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4 comments

  1. Anand Radhakrishnan says:

    Jim, very interesting article. Control valve diagnostic testing should be a must for every downstream manufacturing industry’s Preventive maintenance program. Early leak detection in the control valve seat trim can help process operations make the right decisions. I use to document, control valve diagnostice testing procedures for Ontario Power Generations nuclear facility at Pickering. We use to use Crane Nuclear’s MOVATS diagnostic testing.

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