Bearings

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The reliability of high-speed and high-pressure pumps is crucial to several industries in the Middle East and North Africa. Oil and refinery services and desalination operations, for example, depend heavily on pumps to perform consistently in demanding conditions.

Many industries use variable frequency drives (VFDs) with induction motors. Introduced in the 1960s, VFD technology has advanced considerably during the past 50 years. The engineering advancements have encouraged operators to consider other factors during particular applications, such as harmonics, energy efficiency, temperature, rise time, cable length and switching length.

Despite their simplicity, centrifugal pumps often experience repeat failures that even seasoned maintenance and reliability professionals have trouble preventing. This four-part series explains the reasons behind repeat pump failures and uses a real-world field example involving boiler feedwater pumps.

Minimizing pump downtime directly affects the bottom line. Sealless mag-drive and canned-motor pumps, commonplace in the petrochemical and power industries, enhance reliability and reduce emissions and leakage compared with more traditional “sealed” pumps. The choice between sealless and sealed pumps often involves savings in both time and money.

A multistage BB5 diffuser machine in oil transfer service in the Middle East had been in operation for many years without problems. After a routine maintenance strip down and rebuild, the pump experienced a high thrust bearing temperature of 105 C, which caused it to alarm and shut down. The temperature range had previously been 75 C to 85 C.

Within the oil and gas industry, the rotating shafts of equipment—such as pumps, motors, compressors, gearboxes and turbines—perform an essential function in both upstream and downstream applications. This rotating equipment ensures process flow and the safety of employees and the surrounding community.

Few industries can tolerate the unscheduled downtime of critical equipment. In refinery operations, it can have particularly serious implications. For an operation that runs 24 hours per day year-round, the losses—in both production and profitability—can be staggering.

Active magnetic bearing (AMB) reliability and availability levels have surpassed oil bearings after 10 years of technological advancements. These advances have made an impact on the industry, drawing attention from major original equipment manufacturers globally.

Bearing currents occur in specific motor and drive installations and can lead to motor fatigue and failure. While no system is inherently immune to bearing currents, few installations experience bearing currents during normal operation. While many installations have preventive measures installed, knowing that protection is in place is sometimes outside the owner or operator’s scope.

Misalignment is a frequent cause of rolling bearing failure. It can cause cage fracture, which will result in seizure of the bearing, pump failure and costly downtime. It can also cause edge loading, which will result in early bearing failure.

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Columns

I hope that my last column (Pumps & Systems, September 2014) provided a clearer definition of power factor and how it can be calculated.

Who determines where pressure gauges are located in a pump system? How close to the pump should they be, and what happens if these rules are not followed?

A reciprocating power pump, as depicted in Figure 1, is a displacement machine. It has characteristics that are different than a centrifugal pump.

Blogs

The global water crisis claims 5,500 lives each day—more than war, natural disasters, AIDS or hunger. It is a sobering problem but not an impossible one to solve.

ASTON, Pennsylvania (Sept. 18, 2014) – The Mid-Atlantic Pump & Process Equipment Symposium X was held Sept. 18, in Aston, Pennsylvania. Nearly 300 individuals representing 110 organizations that are customers of Geiger Pump and Equipment attended the single-day symposium.

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