Advanced Engineering Boosts Reliability in Boiler Feed Pump

Posted on September 15, 2016

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 →

Close Inspection Solves High Thrust Bearing Temperature Problem

Posted on September 15, 2016

Careful analysis identified the issue with this multistage, oil transfer pump.

Written by: Gary Dyson (Hydro, Inc.)
Publisher: Pumps & Systems / August 2014

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.

This case study describes the method used to solve the high bearing temperature problem and outlines the flow physics that contributed to the high thrust bearing temperature. The customer contacted an engineering services company after the original pump manufacturer failed to remedy the problem.

The company’s forensic approach to this problem involved two distinct methodologies:

Diligent and in-depth analysis of site data relating to  the problem
Rigorous scrutiny and analysis of the pump geometry and build against the background

The engineering services company identified several scenarios that could cause this temperature rise, then narrowed down the list to establish a root cause.

Site Data Analysis

The behavior of thrust bearing pads during startup is seldom investigated. The temperature rise of the pads can be attributed to two distinct causes—thrust developed during startup and environmental and oil conditions (see Figure 1).

Figure 1. Behavior of thrust bearing pads based on thrust and environmental conditions (Article images and graphics courtesy of Hydro Inc.)

The significant finding from this data was the temperature rise associated with thrust. The pump could not achieve the temperatures measured prior to maintenance in its current condition. The total thrust bearing temperature includes the oil temperature and environmental conditions.

Based on comparisons with previous site data, both the thrust and oil cooling had altered. Analysis of the temperature data at the motor bearings, which were experiencing oil temperature increases of 10 to 15 C, further supported the conclusion. Continue reading →

Optimize High-Energy Pumps With Improved Impeller Design

Posted on September 15, 2016

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.

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

Posted on September 15, 2016

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.

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 →

Hydro’s Test Lab is the first to be certified by the Hydraulic Institute (HI) Pump Test Lab Approval Program

Posted on September 10, 2015

screen-shot-2016-09-23-at-4-49-50-pm We are very pleased to announce that Hydro’s Test Lab is the first test lab to be certified by the Hydraulic Institute in their new pump test approval program.

The Hydraulic Institute which will celebrate 100 years of industry leadership in 2016 is a prestigious organization which develops and delivers comprehensive industry standards and educational programs.

Special thanks to Hydro’s Jeff Johnson, General Manager of the Test Lab and Ares Panagoulias Test Lab Engineer whose dedicated efforts in working with the accreditation team were critical to the approval of our test lab.

Learn more via Pumps & Systems