A nuclear utility had a large circulating water pump with severe vibration issues that required refurbishment in an emergency time frame. Hydro’s Aston, PA service center, which has a 50-ton crane and a history of providing quality repair for nuclear non-safety related equipment, was chosen for this work. Despite the unique challenges in machining and maneuverability presented by large pumps, the DCI and refurbishment were performed in under 2 weeks.
This pump model is an obsolete design with very few existing installations. During the refurbishment process, Hydro’s reverse engineering team captured the data necessary to create a verified model of the pump components. Developing a reverse engineered model was a crucial step in establishing a reliable source to manufacture these large components. With the verified model and Hydro’s casting and machining capabilities, the plant can plan ahead to ensure all critical components are available for future refurbishments.
Hydro was called on to reverse engineer a large circulating water pump in the Caribbean to supply parts for refurbishment. The lead times for receiving parts from the original equipment manufacturer (OEM) were excessive. More concerning, the suction bell provided by the OEM had failed during service. All internal ribs were lost, and the bearing holder was found loose within the assembly.
When Hydro reviewed the design of the suction bell, it was clear that low manufacturing cost was prioritized over reliability. Instead of providing a cast component, the suction bell was fabricated and had an excessively thin wall thickness.
Hydro reverse engineered the suction bell and created a model for a cast component, establishing the rib design and bearing holder location based on design experience. Exterior ribs were added to strengthen the bell and the wall thickness at the suction bell skirt was increased from 3/8” to 2”. The part was scanned on-site within 1 day, with the engineering analysis, modified casting design, and quote for manufacture being
completed within about 3 weeks.
A major county in California found itself in a crisis when its irrigation pumps could not produce the required performance, cutting off critical water supply to the reservoirs and aqueducts. These pumps suffered from high vibration and repeated failures characterized by extreme wear to the propellers, shafts, and bearings.
The OEM had extended their abilities as far as they could but were unable to resolve the problems. Hydro’s engineering team was called on to provide a failure analysis and design an effective solution. Hydro found that deflection induced by high radial forces, excitation of the rotor critical speed at running speed, and faulty protection from sediment all contributed to the failures.
Evans Hydro redesigned the bearing span to counteract the deflection and critical speed issues. The pump-out vanes were also redesigned to provide better lubricating flow to the guide bearings. Finally, the protection rings were redesigned to keep sediment from the propeller and provide better overall dynamic balance.
The solution provided by Hydro significantly increased the life of the pump. Not only were the changes effective, but they were executed efficiently. The modifications were completed in an expedited time frame, allowing the county to resume reliable water service to the agricultural industry that depends on it.
State of the Art Parts: A Gulf Coast refinery had the primary pump for a critical system at the HydroTex Golden Triangle facility for refurbishment. While the primary pump was in the shop, the backup pump operating on-site began to show signs of failure. The impeller of the pump being repaired had extreme wear and was unable to be reused. The shop needed to source an impeller in an expedited timeframe to complete the repair ahead of schedule and get the primary pump back in service before the backup pump failed. Continue reading →
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.