Failure rotating equipment

A more sophisticated and increasingly popular method of on-condItion maintenance is to monitor the performance of equipment on-line. For example, a piece of rotating equipment such as a turbine may be monitored for vibration and mechanical performance (speed, inlet and outlet pressure, throughput). If a base-line performance is established, then deviations from this may indicate that the turbine has a mechanical problem which will reduce its performance or lead to failure. This would be used to alert the operators that some form of repair is required. 

Fatigue failure is likely to occur in equipment subject to cyclic loading for example, rotating equipment, such as pumps and compressors, and equipment subjected to pressure cycling. A comprehensive treatment of this subject is given by Harris (1976). 

Power failure The loss of power will shut down all motor-driven rotating equipment, including pumps, compressors, air coolers, and vessel agitators. 

The use of installed spares and rotating equipment out of service for periodic maintenance should reduce the impacts on production rate from failures in equipment. This conclusion assumes that the resulting complexity of piping layout and increased manipulation of piping connections does not negate the goal of assuring process reliability. 

When handling highly hazardous or flammable materials, it is obvious that the reliability of critical rotating equipment such as blowers, compressors, and pumps is of high importance. Rotating equipment with the highest consequence if a failure would occur (Class 1... 

Inspections of rotating equipment could be accomplished by Preventive Maintenance Programs, which assures that equipment and machine behavior follow some sort of statistical average based upon weeks of operation or throughput in the process stream. Preventive maintenance (PM) programs—the planned, periodic inspection of equipment—reduces the occurrence of unexpected problems. Preventive Maintenance Programs are much more efficient to conduct than the old-fashioned breakdown maintenance programs of previous years in which failures often occur at undesirable times, interfere with production, and may prove to be more costly to correct. [2]... 

Catastrophic electrical failures Unscheduled electrical outages or shutdowns Chronic electrical problems in a piece of equipment or process Excessive steam usage Frozen or plugged product transport lines An inability to predict failures accurately Inefficient use of downtime maintenance opportunities Friction failures in rotating equipment... 

In the design and evaluation of nuclear power plants, internally generated missiles arising from PIEs (such as the failure of pressure vessels and pipes, the failure of valves, the ejection of a control rod and the failure of high speed rotating equipment) should be considered. The potential for secondary missiles should also be evaluated. Measures to prevent the initiation of internally generated missiles should be undertaken if such measures are practicable. 

Typical missiles postulated to be caused by the failure of high speed rotating equipment include ... 

Note to paragraph (a)(2) Critical safety components of mechanical elevating and rotating equipment are components for which failure would result in free fall or free rotation of the boom. 

If a turbine is an alternative power source for rotating equipment, adequate controls should be designed to provide a satisfactory transition to turbine drive during a power failure, and an orderly return to the electric drive once power is restored. 

Equipment failure. Hardware problems occur most fi equently in rotating equipment - pumps and compressors. Fortunately, many problems can be detected in advance, allowing operators to schedule a brief shut-down for preventive maintenance. 

Seal failures are the most common type of failure associated with rotating equipment. Since seals are a barrier between the process and the atmosphere, such failures are often likely to lead to environmental problems, and potentially a safety problem depending on factors such as the flammabUity/toxicity of the process fluid, the size of the leak, and its proximity to personnel or ignition sources. Seal failures can be caused by problems with the bearings, couplings, and shaft vibration. 

Both Low Flow and No How are usually caused by the inadvertent closing of a valve or the failure of rotating equipment such as pumps and compressors. Because such events occur quite frequently, most facilities have plenty of instmmentation and safeguards to respond to these scenarios. 

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