Predictive maintenance meaning

The use of vibration analysis is not restricted to predictive maintenance. This technique is useful for diagnostic applications as well. Vibration monitoring and analysis are the primary diagnostic tools for most mechanical systems that are used to manufacture products. When used properly, vibration data provide the means to maintain optimum operating conditions and efficiency of critical plant systems. Vibration analysis can be used to evaluate fluid flow through pipes or vessels, to detect leaks, and to perform a variety of non-destmctive testing functions that improve the reliability and performance of critical plant systems. 

Predictive maintenance was shown to reduce the actual time required to repair or rebuild plant equipment. The average improvement in mean-time-to-repair, MTTR, was a reduction of 60 per cent. To determine the average improvement, actual repair times before the predictive maintenance program were compared to the actual time... 

A side benefit of predictive maintenance is the automatic ability to monitor the mean-time-between-failures, MTBF. This data provides the means to determine the most cost-effective time to replace machinery rather than continue to absorb high maintenance costs. The MTBF of plant equipment is reduced each time a major repair or rebuild occurs. Predictive maintenance will automatically display the reduction of MTBF over the life of the machine. When the MTBF reaches the point that continued operation and maintenance costs exceed replacement cost, the machine should be replaced. 

Recent advancements in microprocessor technology coupled with the expertise of companies that specialize in machinery diagnostics and analysis technology, have evolved the means to provide vibration-based predictive maintenance that can be cost-effectively used in most manufacturing and process applications. These microprocessor-based systems simplify data acquisition, automate data management, and minimize the need for... 

Experience shows that some machines have more frequent failures than do others. Obviously, different failure modes have different frequencies of occurrence. This is usually described as mean-time-between-failure (MTBF) and expresses the probability of machinery failure and breakdown events as a function of time. This is of particular interest to the maintenance failure analyst and troubleshooter who have to grapple with the realization that some machinery failure modes appear slowly and predictably whilst others occur randomly and unpredictably. In most cases, both types of failures have been encountered. 

This means that, under conditions of catabolite limitation, Eqn. 70 will give the most easily interpretable relation. Conversely, under anabolite limitation, Eqn. 71 will be the most practical. Both equations predict a linear relation between rate of substrate utilization and biomass formation. Furthermore, the relation between catabolism and anabolism has a positive intersection point with the ordinate. This positive catabolism at (extrapolated) zero growth rate has been interpreted as maintenance energy requirement [52]. It follows naturally from the simple description of bacterial metabolism as we have used it here. 

The stability of proteins refers to the maintenance of a defined three-dimensional structure with specific thermodynamic and functional properties. High-resolution structures in the crystalline state and in solution have reached a stage at which the atomic coordinates of proteins can be compared with an accuracy down to root mean square deviation (r.m.s.d.) values less than 1 A. However, even this precision does not allow the fi ee energy of stabilization to be calculated from the coordinates, nor does it allow predictions with respect to the dynamics of functionally relevant local interactions in active or regulatory sites of homologous proteins. The fluctuations between preferred conformations of native proteins involved in such functionally important motions may very well show amplitudes and angles of up to 50 A and 20°, respectively. ... 

For workers at the facility (including contractors and visitors), it is legitimate to take credit if the normal pattern of work associated with the job role means that they would only reasonably be expected to be in the hazardous area for part of their time at work. For example, a worker may have a patrol route that means that they are outside the predicted hazardous area for part of their shift. Maintenance crews may work over a whole facility and may only be present in the hazardous area for a portion of the time they spend at work. 

Predictable and regular basis means employee functions such as, but not limited to, inspections, service, repair, and maintenance which are performed ... 

Improved regulatory control can reduce maintenance costs. It is self-evident, if pumps and compressors are subject to fewer pressure surges, temperature deviations and so on, then bearings, seals and gearboxes are less likely to fail. While virtually impossible to predict these savings there have been cases where the mean time between failures (MTBF) for machines in difficult services have increased by a factor of three. If the equipment is critical, in that its failure requires a process shutdown or turndown, then not only are maintenance costs reduced but process capacity is increased. 

In our model, we assume that the monitored equipment now have a normally distributed failure time (instead of exponential) with an unchanged mean value, thus reflecting the results of the condition monitoring and prediction analysis. The previously defined inspections for the 3 items are cancelled and the Preventive Maintenance Optimization module is now used to find the best schedule to perform preventive replacement. 

Software diversity has been advocated as a means of improving the reliability of safety related software and in particular safety systems that react to a demand, where a 1 out of 2 or a 2 out of 3 voting scheme can be used to ensure that some safety action is performed. This approach is used in industry (e.g. for railway interlocking), but development and maintenance is costlier than for a non-diverse system and it is not easy to predict in advance the likely safety improvement that can be achieved. 

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