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Abstract

A detailed experimental study was conducted to determine the lowest detectable compressed air leakage rate through an industrial control valve that can be reliably detected using an acoustic emission (AE) technique. Through-valve leakage was deliberately introduced into a 25.4 mm (1 in.) hard-seat globe type control valve under controlled conditions. This was achieved by carefully adjusting the control signal, 4-20 mA d.c., to the valve positioner which, in turn, varied the clearance between the valve plug and seat. Two AE sensors together with the state-of-the-art data acquisition and processing systems were used to monitor a wide range of leakage rates under different working conditions. The effects of the background noise on the measured AE signal were considerably reduced by using the real-time programmable filters that were part of the AE measurement system. This was carried out to produce more reliable and consistent results. The sensitivity of the AE sensors was improved by using line amplifiers with variable gain. The frequency spectrum analysis of the AE signal indicated that leak-related frequency components can be clearly distinguished from those produced due to background noise. Furthermore, it was evident that the selected leak-related frequency components increased in their amplitude as the leakage rate was increased. The paper concludes by illustrating that AE can be used reliably to detect the onset of air leakage through control valves at a differential pressure that could be as low as 110.3 kPa (1.103 bar) and in a noisy industrial environment.

Keywords

Control valves leak detection acoustic emission techniques frequency spectrum analysis.

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References

Badinier, C. , and Dimmick, J.G. 1984. 'Nuclear valve leak detection by passive acoustic spectrum analysis', Proceedings of the 6th International Conference on NDE in the Nuclear Industry, Zurich, pp. 367-372.

Delarue, V. 1996. 'Leak detection and location for gas transmission pipelines' , Proceedings of the 1st International Conference on Pipelines (IPC), Calgary, Vol. 2, pp. 1109-1115.

Dickey, J. , Dimmick, J. , and Moore, P.M. 1978. 'Acoustic measurement of valve leakage rates', Materials Evaluation, 36, 67-77.

Dimmick, J. , Nicholas, J. , Dickey, J. , and Moore, P.M. 1979. 'Acoustical valve leak detector for fluid system maintenance', Naval Engineering Journal, 91(2), 71-83.

Drouillard, T.F. 1996. 'A history of acoustic emission', Journal of Acoustic Emission, 14(1), 1-33 .

Ellingson, W.A. , and Sullivan, J.W. 1981. 'Acoustic valve leak detection', Proceedings of 6th Annual Conference on Materials for Coal Conversion and Utilization, IL, USA, pp. 24-48.

Germain, J.L. , Granal, L. , Provost, D. , and Touiliez, M. 1996. 'Inspection systems for valves monitoring at EDF', Proceedings of the International Conference on Condition Monitoring and Diagnostic Management (COMADEM), Sheffield, pp. 411-420.

Lord, A.E. , Deisher, J.N. , and Koerner, R.M. 1977. ''Attenuation of elastic in pipelines as to acoustic emission leak detection', Materials Evaluation, 49-54.

Rajtar, J.M. , and Muthiah, R. 1997. 'Pipeline leak detection system for oil and gas flow lines' , Journal of Manufacturing Science and Engineering, Transaction of the ASME, 119(1), 105-109.

10.

Sharif, M.A. , and Grosvenor, R.I. 1998a. 'Process plant condition monitoring and fault diagnosis' , Proceedings of the Institute of Mechanical Engineering, Part E, Journal of Process Mechanical Engineering, 212(E1), 13-30.

11.

Sharif, M.A. , and Grosvenor, R.I. 1998b. 'Fault diagnosis in industrial control valves and actuators ', Proceedings of the IEEE International Conference on Instrumentation and Measurement Technology (IMTC/98 ), Minnesota, USA, pp. 770-778.

12.

Smith, T.R. 1993. 'Development and use of an effective acoustic valve leak detection system', Proceedings of the American Power Conference , 55(1), 899-904.

13.

Thompson, G. , and Zolkiewski, G. 1997. 'An experimental investigation into the detection of internal leakage of gases through valves by vibration analysis', Proceedings of the Institute of Mechanical Engineering, Part E, Journal of Process Mechanical Engineering, 211(E3), 195-207.

14.

Williams, R.V. 1980. Acoustic Emission, Adam Hilger Ltd , Bristol, pp. 52-70.

Internal valve leakage detection using an acoustic emission measurement system

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