Pump Renovation Restores Balance

Posted on December 27, 2017

Vibration issues with a two-stage pump forced a major steel manufacturer to remove the pump from service. Due to incorrect weights welded on an impeller, a steel manufacturer called upon Hydro to repair and balance a two-stage pump.

Written by: Ken Babusiak (Hydro, Inc.)
Published by: World Pumps

The pump was experiencing the vibration during the spring and summer months of 2016. The steel company sent the pump to HydroAire’s Chicago, IL facility in September of that year. HydroAire was able to determine the cause of the vibration and created a solution that got the pump back in operating condition. The pump was installed and back in service by February, 2017.

The initial testing and analysis deter-mined that the impeller had large weights welded onto it. The steel company was concerned for many reasons, especially because the staﬀ knew that using weights was not the correct way to balance an impeller. This caused the steel manufacturer to question the manner in which the pump had previously been repaired.

Adding weights to impellers is generally not standard practice.

Where not to position the weights.

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Using Latest Technology to Refurbish a 50-year-old Pump Element

Posted on December 26, 2017

Power pump performance improved with redesign of the first-stage, double-suction impeller and twin volute.

This project has been divided into two articles. The first, published in the June 2017 Pumps & Systems; the second, published in September 2017 Pumps & Systems.

Written by: Dave Allard & Dr. Gary Dyson
Published by: Pumps & Systems

In the aftermarket business, part replication is not enough. Precision engineering combined with the latest technology are essential for manufacturing high-quality parts. A main boiler feed pump at a Midwestern United States power plant was built in 1967 using sand casting and wooden patterns, now considered outdated technology. Even though the pumps received refurbishment every six to eight years, the pumps continued to have low performance as well as vibration issues.

Using all its resources—including casting simulations, 3-D models, up-to-date foundry casting techniques and considerable engineering data—Hydro fully manufactured a complete element, performed sophisticated testing in the Pumps Test Lab Approved Program (PTLA) certified test lab, and returned the pump to operation within just 12 weeks.

This project involved the manufacture of a complete first stage twin volute and a description of the latent defects.

The pump suffered from ongoing vibration issues which were caused by pressure pulsations at vane frequency. To improve the vibration levels, hydraulic analysis and redesign were required to develop a new, improved design.

This project has been divided into two articles. The first is the manufacturing of the twin volute and the second is the design of a new impeller.

Image 1. A received bundle showing failure in the twin volute stage piece. Hydro received the internal element and casing (pump bundle, or element) of the pump. (Images and graphics courtesy of Hydro, Inc.)

The first-stage twin volute is a complicated casting, which failed during operation as a result of poor design.

Hydro re-engineered the casting by using sophisticated engineering and 3-D modeling, along with simulation software and 3-D sand printing.

In addition, Hydro identified the opportunity to improve the performance of the pump by redesigning the first-stage double-suction impeller. To improve vane passing frequency, the first-stage double suction impeller was redesigned with staggered and split vanes.

Hydro’s aftermarket services capability provided a completely new replacement element for this high-energy boiler feed pump and also redesigned the castings to eliminate the original latent defect in the casting design.

Hydro provided sophisticated hydraulic engineering improvements to increase the mean time between repairs (MTBR) of the newly manufactured element.

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Hydro Middle East performs swift re-build on fire-damaged circulating pumps

Posted on December 26, 2017

Hydro Middle East, specialists in pump rebuilding, particularly in the oil and gas industry and other industrial markets was called in to assess the damage and redesign and rebuild the fire-damaged pumps. Hydro’s engineers first evaluate the causes of any pump damage or failure and then provide expert engineering analysis and a responsive field service.

Written by: Thomas Arakal (Hydro Middle East)
Published by: World Pumps

Two fire damaged pumps arrive at the Hydro Middle East Service Centre.

Analysis & recommendations

In the case of the fire-damaged pumps, once the fire was under control, Hydro immediately sent a field engineer to the site to conduct a root cause analysis and make recommendations to ensure that the equipment would be restored within the very fast turnaround that the company required.

The engineers discovered that the fire had been so severe it had completely burned out all of the oil in the bearing housing. In addition, the baseplate was also warped because of the excessive heat. A turnaround of between two and three weeks for redesign and rebuild was proposed, subject to mechanical seal availability and the two hot oil circulating pumps, along with the baseplate and the motors were shipped to Hydro Middle East’s facility in Dubai, U.A.E.

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Emergency Nuclear Pump Rebuild

Posted on July 7, 2017

Faisal Salman and Nick Dagres of Hydro, Inc report how performing new design modifications on two critical safety-related charging pumps have extended their lifespan and reduced maintenance.

Written by: Faisal Salman & Nick Dagres
Published by: World Pumps

Setting up the pump at Hydro’s Hydraulic Institute Certified Test Lab.

A Western European nuclear power plant was having difficulty meeting the necessary hydraulic performance at runout for two centrifugal charging pumps. The system needed 30 ft of Net Positive Suction Head required (NPSHr).

The pumps are safety-related pumps, which pump bore-rated water (water mixed with boric acid) into the reactor to kill nuclear fission. What water is to fire, bore-rated water is to nuclear fission. Bore-rated water kills nuclear reaction.

The two pumps are each about 15 ins in diameter and about 100 ins in length. They were shipped from the Western European site to Hydro, Inc.’s Chicago, IL facility to conduct analysis, redesign, manufacturing, and testing.

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Quality Nuclear Performance Testing in Urgent Conditions

Posted on July 7, 2017

A 5-day emergency testing turnaround for a nuclear pump proved no problem for this world-class testing facility.

Written by: Nick Dagres & Faisal Salman
Published by: Nuclear Plant Journal

When a vertical safety-related residual heat-removal pump failed its required surveillance performance test at a nuclear power plant, it created the need for emergency hydraulic performance and vibration testing. The plant required the pump back in operation within one week, to prevent shutdowns that could cost the facility up to $1 million per day.

The plant contacted Chicago based Hydro, Inc., which has Hydraulic Institute (HI) Pump Test Lab Approval (PTLA) – certified testing facilities and the ability to perform crucial testing on an urgent basis.

Background
During a routine check by the regulator, a safety-related heat removal pump failed its required in-house surveillance pump performance test. With a safe shutdown of the unit, the plant entered an LCO (Limited Conditions of Operation) period. The power station shut down the unit but wanted to avoid a full shutdown of the facility. This created an emergency situation for the plant.

According to the regulator’s strict standards, if performance requirements are not fulfilled immediately, the plant can be shut down completely. The LCO allows the plant to continue to operate as long as the problem is being resolved in a limited time frame. In this case, the time frame was seven days. To allow for shipping to and from the facility, Hydro had only five of those days to complete the project. The plant was concerned that the repair time might exceed the LCO. Other similar pumps remained in operation performing the same function, however the unit was shut down because there were no spare pump store place it while testing was being
performed. The original equipment manufacturer could not schedule the required tests in the abbreviated time span; therefore the Chicago service company was commissioned. Under normal conditions the scope of work would generally take about six to eight weeks to complete.

Pump as received

Identifying the Problem
In such cases, the regulator requires that a third party inspect the equipment to discover whether the issues were with the instrumentation or with the pump itself. As a result, immediate testing was required to determine whether the pump was functional.

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