machinery health

Enveloping is a tool that can give more information about the life and health of important plant assets. It is primarily used for early detection of faults in rolling element bearings and gearboxes. Enveloped acceleration is an especially valuable parameter to trend, as the progression of machine condition can be evaluated. Armed with good information and assisted by service experts, plant engineers can be confident in the proper operation and management of the important assets in their care.
Last month, we looked at adjustable frequency AC drive system, induction motor speed control and motor application and performance. This month we will explore specific operation conditions, applications and performance.
On July 16 last year, a high-speed centrifugal pump failed catastrophically at a large refinery in South America, causing production losses and costing a substantial amount of money for repairs. The inboard bearing of the pump lost lubrication, overheated, and seized up.
Regular care and inspections help prevent costly downtime.
This article explores the use of condition monitoring at the UPM-Kymmene's Wisaforest pulp and paper mill in Finland. Production capacity is 800,000 air dried tons per annum (ADt/a) of pulp and 180,000 ADt/a of kraft and sack papers.
Beating occurs when two dynamic excitation sources (forces) are close together in frequency, and a pathway allows the two excitation forces to transfer to each other. The beating effect results because the frequencies are so close to each other that the waveforms alternately reinforce each other at some times and cancel each other at other times. When the vibration from each source adds constructively, the vibration increases. When the vibration adds destructively, the vibration decreases.
A new technology provides operating personnel with frequent information for those situations when maintaining pump operation is critical to process integrity.
Analytical methodology and autocorrelation can be very effective for monitoring and evaluating the state of lubrication in rotating machinery.
Why integrating vibration monitors with process controls provides fast response to pump faults, adds predictability and avoids unexpected shutdowns.
Vibration monitoring of rotating equipment and analysis of the resulting data are effective ways to evaluate the health of production machinery in order to achieve best maintenance practices, extend equipment longevity, and avoid unplanned shutdowns. Plant equipment seldom fails without giving signals well in advance, so breakdowns can normally be predicted by listening for the warnings and passing that knowledge on to those in a position to prevent such problems.
Your pumps benefit from regular checkups to ensure no underlying problems exist.
Monitoring motor-pump combinations for signs of impending problems provides useful information to prevent pump failure and minimize costly downtime. Since rotating machines exhibit recognizable failure modes that are revealed by their vibrations, analysis of vibration data can identify changing conditions and diagnose an evolving problem. This can be the difference between a plant or mill continuing to operate or having to shut down for unscheduled repairs.
Even when a redundant pumping system is in place, it can be advisable to monitor the condition of the operating units in critical applications where maintaining production depends on motor-pump reliability.
If pump cavitation is not detected and quickly eliminated, significant damage can occur to the impeller and other internal components. Since cavitation (the formation and collapse of vapor bubbles in the pumped fluid as it passes through the pump impeller) is often temporary or even induced by the process, timely knowledge of the condition is extremely important so operators can act to alleviate the problem and prevent damage.
Potential to Failure (P-F) curves graphically display the failure time cycle and measurement techniques that can be used to detect asset failures prior to reaching the asset incurring functional failure. Proactive strategies should focus on managing assets high on the P-F curve, or early (P1 to P5) in the failure cycle (Figure 1). The ability to detect failures early in development allows top quartile performers to proactively manage their maintenance programs by understanding the health of their assets. Many companies, however, find it difficult to operate proactively and continually react to assets that reach functional failure with little or no warning.
It has been 54 years since Tracy Hall invented the first manmade diamond at the General Electric (GE) laboratories in Schenectady, New York.
Of the technologies available for condition monitoring of rotating equipment, the quickest return on investment is from vibration analysis. For the novice, vibration data seems complex and is generally difficult to assess compared to other techniques. Once trained, however, the novice can recognize the patterns and diagnose a machine problem.
Third in a series. Advances in wireless technologies can help address many common failure modes in mid- to low-level criticality assets and eliminate wiring costs for a range of asset types.

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