Acoustical Valve Leak Detector for Fluid System Maintenance

Abstract

A portable, passive, non‐destructive, non‐intrusive instrument is currently in use by the U.S. Navy to detect fluid leakage through shipboard steam, water, hydraulic, and high‐pressure air valves. The Acoustic Valve Leak Detector (AVLD) was developed by the David W. Taylor Naval Ship RID Center (DTNSRDC) under the financial sponsorship and technical direction of the Nuclear Powered Fleet Ballistic Missile Submarine (SSBN) Ship Systems Maintenance Monitoring and Support Office (SMMSO) of the Naval Ship Engineering Center. The instrument is used to identify more precisely internal leakage points which may require opening and visual inspection of Submarine piping system. “Open‐and‐inspect” routines generate both risk of system damage and high man‐hour expenditure. The degree to which such procedures are necessary to achieve confidence in the material condition of systems is dependent on the availability and performance of non‐intrusive test equipment which can detect and assess the nature and degree of malfunctions. The development, design, operations, limitations, and successful applications of the existing AVLD are described. The AVLD is currently being used for troubleshooting, for overhaul planning, and in a systematic preventive maintenance program for seawater valves. Plans for future development and progress achieved in current work are described. The AVLD listens for the ultrasonic acoustic emissions characteristic of internal valve leakage and uses transducers attached temporarily to the valve or adjacent piping. The background spectra of structureborne noise can be subtracted automatically by the AVLD when a second transducer is attached to the piping system at a point far enough away from the valve in question that it picks up no leakage noise. Since the transducers are attached to the outside of the valves, the time and expense of dismantling the valves or of removing them from the systems are avoided.

Smart portable noninvasive instrument for detection of internal air leakage of a valve using acoustic emission signals

“…For the prediction of gas leakage rate through a valve, we used a regression model to estimate the function f in Eq. (1).…”

“…Therefore, it is not convenient to use in applications where mobility is demanding. Some commercially available portable AE systems at present are costly and the leakage rate are calculated offline [1]. Moreover, the precision of the leakage rate measurement is still rather low.…”

Nondestructive Detection of Valves Using Acoustic Emission Technique

“…Through the analysis of amplitude, counts, hits, and time of AE signals from corrosion, different types of corrosion could be identified [17]. The acoustic valve leak detector (AVLD), developed by the David Taylor Naval Ship RID Center (DTNSRDC), was currently being used for troubleshooting, overhaul planning, and a systematic preventive maintenance program for seawater valves [65]. Noipitak et al presented a relative calibration method for an internal valve leakage rate measurement system based on the microcontroller and AE methods.…”

Quantification of valve leakage rates

“…The focus in this article are methods that can be applied remotely and with minimal intrusion and downtime required to the system. The instrumentation that has been the most thoroughly investigated for automated leak detection includes: Acoustic Emission (AE),3–10 vibration monitoring,11, 12 and cavity Dynamic Pressure (DP) monitoring 13…”