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.
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.
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.
The phenomenon occurs when a system experiences extreme vibration caused by excessive pump pressure and pulsation.
Written by: Greg Matteson & Jeff Johnson Published by: Pumps & Systems
A North American natural gas liquids pipeline company was experiencing an acoustic resonance issue that cost up to $35,000 a month in maintenance and repair. A six-week project resulted in rerating three American Petroleum Institute (API) designation between-bearing (BB3) horizontal multistage split-case mainline pumps and performing extensive and specific vibration analyses to identify the problem. The project involved designing and manufacturing new impellers using exclusive milled vane technology, conducting API hydraulic performance tests, and returning the pumps into service.
This midcontinent pipeline gathers, processes, stores and transports natural gas—in this case, propane. Because of its geographic location, extreme temperatures and conditions are a factor in the selection of major equipment and components. The pumps operate at 2,917 gallons per minute with 2,926 feet at 1,500 horsepower and 3,560 revolutions per minute (rpm).
The pipeline company was experiencing an acoustic resonance vibration problem at the pump crossover, causing major maintenance and repair issues. Acoustic resonance occurs when a system experiences extreme vibration due to excessive pump pressure and pulsation, with frequencies loud enough for humans to hear. This can happen with the use of variable speed drives.
The pulsations are caused by a non-uniform flow from turbulence, sudden change of flow structure, direction or cross-section.
The acoustic resonance had existed since the pumps were installed more than five years ago. Rather than repairing or replacing them, the company performed continuous unscheduled maintenance that cost as much as $35,000 in a single month.
Hydro Inc. has a strong engineering capability and an expansive global reach in the pump industry, especially in aftermarket services. Pump Engineer had the pleasure of speaking with George Harris, Chief Executive Officer and Founder of Hydro Inc., where he discussed the company’s recent research initiatives, reliability support for customers, customized designs and the significance of upgrades and health audits.
Written by: Deirdre Morgan Publisher: Pump Engineer / December 2016
“We were very fortunate that early in the company’s development we had the good fortune to work closely with Dr. Elemer Makay, a foremost consultant to the power generation industry and a specialist in troubleshooting multi-stage, high energy pumps”, states Harris. “Engineering combined with meticulous observation and analysis in the field were key to his troubleshooting process. As a result of his training over a twenty year period, engineering became the focus and strength of Hydro Inc.’s aftermarket services”.
According to Hydraulic Institute statistics, 85% of the critical pumps in industries, such as power, refineries and pipelines, are custom designed for the specific application intended. In order to properly rebuild, upgrade or troubleshoot these installations requires a solid aftermarket engineering capability and experience. Not only must the engineer understand pump fundamentals, but also the application and system in which the pump is being used, as well as the changes that may have occurred in plant operating conditions since the pump was originally installed.
Written by: Greg James Publisher: Pump Industry / November 2016
Rebuilding a typical boiler feed pump cartridge and returning the running clearances to specification is a critical process for effective and efficient plant operation. The cost to rebuild a cartridge – supply new mechanical seals, bearings and consumables, the lost production, down time and the labour costs – is a significant investment.
After rebuilding a cartridge and returning all operating clearances to specification, the good work can be greatly affected by installing the cartridge into a distorted barrel and/or discharge head combination.
Join instructor, Robert Piotrowski of Turvac, Inc., as he discusses the key ingredients to successfully align machinery, the symptoms you will see if machinery is subjected to run under a misalignment condition, and more.