Vibration surveillance

Effective predictive maintenance programs incorporate multiple features. However, the key to rotating equipment predictive maintenance is a comprehensive vibration surveillance and analysis program. A change in a machines health or operation nearly always causes an easily detectable vibration change long before the machine fails. 

Postponing maintenance when it can be delayed safely. Certain costly steam turbine/gen-erator units outages were scheduled every six years. With the data obtained through vibration surveillance and analysis methods, the intervals between overhauls were extended with the concurrence of the property insurance carrier. 

Ronnie W. LeBlanc, Loss Prevention through Machinery Vibration Surveillance and Analysis, Plant/Operation Progress 5 no. 3, July 1985 pp. 179—82. 

The Vibration Inspectors at PPG-Lake Charles collect data on 27,000 data points from 2,100 equipment sets. The vast amount of data requires a Pentium computer with a 2-gigabyte hard disk to manage it. R. W. LeBlanc described the benefits of a proactive vibration program by citing a number of case histories (1985). His list of success stories [10] of a vibration surveillance and analysis includes ... 

Monitoring should include the usual parameters worthy of surveillance in high-speed turbo machinery the temperature of journal bearings, vibration and axial position of the pinions, inlet and discharge temperatures combined with discharge pressure from the individual compressor stages, and various lube oil system devices. Competent manufacturers make sure all measurement locations are completely prewired on the machine and made available at predefined interfaces or in terminal boxes for connection at the plant site. 

Surveillance. Vibration and magnetic sensors can detect vehicle and personnel movement. 

Three well-trained, full-time, energetic analysts comprise the surveillance crew of the PPG Industries Vibration Group. The technicians develop their skills through self-study, peer support, periodic out-of-plant training, years of experience and participation in the Vibration Institute. The program has three fundamental components Surveillance, Analysis, and Correction. 

After the initial programming of the state-of-the-art data collector units, a display window on the module provides a description of each piece of equipment on the surveillance route in sequence. The vibration inspector, prompted by the instrument readout, walks up to the operating equipment described on the display and thrusts a probe on the indicated bearing or other data point. When the analyst presses a button, the module captures the vibration level and any required analysis data. The data collector automatically identifies troubled sets based upon preset alarm values and collects spectrum data. Once the data col-... 

Technicians require minimal effort to generate surveillance and summary reports, once the vibration data is collected. The vibration signals from the operating equipment is computer classified using proprietary computer programs into three levels of operation (1) Smooth, (2) Marginal, and (3) Rough. 

The team generates reports for two management reports. Vibration inspectors generate and distribute detailed surveillance reports to the equipment owners and the area maintenance supervisor so that corrective action can be planned. The inspectors also provide a summary report for middle management. 

Smydi, A. W., Masri, S. F., Caughey, T. K. and Hunter, N. F. Surveillance of intricate mechanical systems on the basis of vibration signature analysis. Journal of Applied Mechanics (ASME) 67(3) (2000), 540-551. 

The exposure limit value (ELV) is the maximum amount of vibration an employee may be exposed to on any single day. It represents a high risk above which employees should not be exposed. Daily ELV is 5m/s Health and safety surveillance, information and training must be provided by the employers. 

HUMS (Health and Usage Monitoring System) is a system for technical condition surveillance (e.g. vibration monitoring) that has continuously improved during the study period. Analysis of HUMS-data may give early warnings of anomalies and deviation not easily detectable by other means. The use of HUMS is widely considered as an important improvement to helicopter safety. 

For primary or secondary piping without qualification for leak before break or for break preclusion, the probability of a pipe break can be reduced significantly if additional safety orientated measures are applied, such as surveillance measures (increased in-service inspections or monitoring for leakage, vibration and fatigue, water chemistry, loose parts, displacements, and erosion and corrosion). 

Service air Air compressor foundation Foundation failure Special surveillance Cracking of concrete Vibration —... 

Corrosion of vessel internals, vibration and failure, the possibility of which should be detectable by suitable surveillance means ... 

Various methods of on-line reactor surveillance have been used, including neutron noise monitoring in boiling water reactors (BWRs) to detect internals vibration, and pressure noise surveillance at TMI-2 to monitor primary loop degasification. On-line surveillance data has been used in the assessment of loose thermal shields. 

The acceptance criteria for the resolution of GSI I.D.5 (3) for internals vibration monitoring are provided in ANSI/ASME OM-5-1981, (Reference 2). This standard provides non-mandatory recommendations on the use of ex-core neutron detector signals for monitoring of core barrel axial preload loss. This standard also documents a program containing baseline, surveillance and diagnostic phases and provides recommendations for data acquisition frequency and analysis. 

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