How Root-Cause Analysis Solved a Vertical Turbine Pump Failure

A comprehensive approach to reverse engineering helped to establish the differences between the stainless steel and original bronze impellers.

Written by:  Hydro, Inc.
Publisher: Pumps & Systems / March 2016

 

When a severe pump failure involving one of three installed circulating water makeup pumps happened, facility personnel grew concerned about the root cause. The subject pump failed just 40 days after its commissioning.
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Image 1. A crack in the discharge head flange that involved fatigue failure of the weld of a pump.

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Image 2 (right). The pump’s impeller wear ring landing shows heavy scoring.

The equipment in question consisted of three-stage vertical turbine pumps running either in standalone or in parallel operation as required. The failure manifested itself through high vibration and caused severe scoring of the pump shaft and wear ring landings, leading to fatigue failure of the weld on the discharge head flange (see Images 1 and 2). The commissioned pump was refurbished and rebuilt by another company’s service center with spare impellers supplied by an original equipment manufacturer. No changes to the geometry had reportedly been made, although the impeller material had been upgraded from bronze to stainless steel.

The plant initiated its internal root-cause analysis process, and the failed pump required emergency repair. The station sought a company to conduct the repair, and the firm reviewed the customer-supplied documents and background providing the possible causes of the failure. Continue reading

Advanced Engineering Boosts Reliability in Boiler Feed Pump

This approach incorporated reverse engineering, design verification and casting simulation to address equipment failure.

Written by: Dr. Gary Dyson and Jesse Stinson (Hydro, Inc.)
Publisher: Pumps & Systems / December 2015

 

Pump technology requires the extensive use of castings to form the complex shapes needed to guide process fluids through the machine. The shape of these passages is crucial to the machine’s performance.

Pump designers spend extensive time designing and optimizing the shapes of these passages to optimize the machine’s efficiency. Unfortunately, casting processes cannot always represent the pump engineer’s true design intent, and the manufacturing processes have a direct impact on the machine’s reliability and design integrity. Designers take these processes into account when proposing their designs, but sometimes the deficiencies of the casting process become apparent after a major equipment failure.

One example involved determining the root cause behind the first-stage failure of a Worthington 12-WCND-166 six-stage boiler feed pump. The pump exhibited high vibration and performance degradation, and it was taken out of service. The inspection determined that a crack had resulted from a welded core plug. Continue reading

Hydro Inc. is Carving out their Niche in the Global Pump Aftermarket

Written by: Sarah Schroer
Publisher: Pump Engineer / June 2015

 

Pump Engineer spoke with George Harris, Hydro Inc.’s CEO and Founder, to learn more about what sets them apart from other pump aftermarket services. “Hydro has developed a unique niche where we have the capabilities, the engineering support, and the lab for testing purposes to provide comprehensive support for customers, while providing prompt capable service on a global basis,” says Harris. Hydro Inc. makes customers the cornerstone of their business. “Everything that we do is focused on the needs of the customer,” explains Brian Scorer who is the Executive VP at Hydro Inc. “We make sure we are entrepreneurial, fl exible, agile, and very quick in the way that we go about our business. We provide world class quality, world class delivery, and we wish to be competitive on cost. The foundation for what we do is built upon engineering excellence and technology. We also have some of the world’s best pump engineers.”

 

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Werner Barnard and Dr. Gary Dyson of Hydro, Inc.

Continue reading

Optimize High-Energy Pumps With Improved Impeller Design

As new design and manufacturing technologies are developed, end users can affordably upgrade their systems and verify better performance.

Written by: Bob Jennings & Dr. Gary Dyson (Hydro, Inc.)
Publisher: Pumps & Systems / August 2015

 

The rising cost of electrical power has caused many industrial plants to shift their focus to energy consumption. Plants often run pumping equipment continuously, and much research has pointed to opportunities for cost savings by optimizing pumping equipment.

When evaluating the potential for energy savings, end users cannot consider a pump in isolation. The suitability of the pump for the system within which it operates is vital. Even the best designed and most efficient equipment offers power-saving potential if it is run off its best efficiency point (BEP) in a system for which it is ill-applied.

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Image 1. Much research has pointed to opportunities for cost savings by optimizing pumping equipment. (Images and graphics courtesy of Hydro, Inc.)

Many plants have been in operation for more than 40 years, and their operating philosophies have changed over time. Plant improvements have enabled higher throughput, often increasing production by as much as 125-150 percent. Unfortunately, little is done to improve or increase the performance of the support-service pumping equipment, such as cooling water pumps.

As system flow demands increase, the duty point of the pumps is forced to shift far to the right of the BEP, well outside the acceptable operating range (AOR). This causes efficiency and pump reliability to decrease dramatically.

Casting tolerances, surface finishes, and impeller/volute or impeller/diffuser geometry have all dramatically improved during the last 40 years. But because many pumps were installed when the plants were commissioned, the existing pumps were manufactured using techniques that would be considered obsolete today. The result is higher energy costs and reduced reliability and availability, which often cause production delays. Continue reading

10 Key Facts About Reciprocating Pumps

This pump type’s unique system design requirements are often ignored or misapplied, which affects reliability and operation.

Written by: Gary Dyson and Herb Tackett Jr. (Hydro, Inc.)
Publisher: Pumps & Systems / July 2015

 

Because Centrifugal pumps are widely used, pump and rotating equipment engineers are generally familiar with this equipment’s operating principles, performance curves and selection criteria.

 

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Image 1. While centrifugal pumps are the subject of much training, the dwindling population of reciprocating pumps has led to a loss of understanding of this pump type’s unique system design requirements. (Images and graphics courtesy of Hydro, Inc.)

 

While Centrifugal pumps are the subject of much training, the dwindling population of reciprocating pumps has led to a loss of understanding of this pump type’s unique system design requirements. Centrifugal pump specifications are now commonly and incorrectly applied to reciprocating pumps, which can lead to significant reliability problems.

End users should consider these 10 key facts about reciprocating pumps that can influence reliability and operation. Continue reading