Hydraulic Rerates & Pump Efficiency

During a mechanical seal replacement at a major gas plant, a reliability engineer identified that their API OH2 centrifugal pump was operating below the Minimum Continuous Stable Flow (MCSF).

In this case, Hydro Rocky Mountain partnered with HydroTex Deer Park‘s engineering team to provide the customer with an innovative solution by utilizing the existing casing and providing a redesigned impeller to optimize the overall efficiency and life cycle of the unit.

Watch as Ares Panagoulias and Glen Powell, of Hydro’s test lab, examine the historic operating conditions in regard to the pump’s best efficiency point (BEP) and provide a performance test to validate the upgrades and modifications.

Case Study: Hydraulic Rerates & Pump Efficiency from Hydro, Inc. on Vimeo.

Read the full article on World Pumps: worldpumps.com/ancillary-products/features/seal-replacement-reveals-causes-of-vibration/

Maximizing Efficiency in Descaling Pumps

descale pump impeller damage

Damaged impeller showcasing severe corrosion.

A major steel plant on the East Coast had been experiencing catastrophic failures with its five-stage descaling pumps. The plant operated using three multistage axially split (BB3) pumps with two spares. All five of the pumps had a mean time between repair (MTBR) of two years. In this case, the plant water quality was considered to be less than ideal, and the entrained abrasives were a factor contributing to the repeated failures.

Poor water quality can lead to a number of pump reliability issues. When pumping fluids with abrasive material, pumps experience erosion and corrosion, and the effects can rapidly degrade both the casings and critical inner elements. While erosion and corrosion alone are not always a difficult problem to solve, it is important to have a firm understanding of the relationship between various types of erosion and corrosion and the metallurgy used in designing the pumps.

Further analysis showcased excessive clearances and inconsistencies with component fits that also contributed to pump performance degradation outside the abrasion. In order to increase the MTBR of the pumps at the plant, the aftermarket pump service provider recommended several engineered upgrades including new impellers to be manufactured using advanced mold technology, specifically addressing the surface finish and dimensional consistency.

Read the full article at pumpsandsystems.com

Optimizing Reliability Through Material Upgrades

centrifugal pump test

The 14-stage boiler feedwater pump installed for testing to ensure that the performance achieves desired operating conditions.

At a combined cycle power plant, a boiler feedwater pump was experiencing problems. Dr. Gary Dyson of Hydro, Inc. and Larry White of HydroTex discuss how major cost savings were provided through engineering analysis, material upgrades and testing for validation.

A combined cycle power plant in the Pan Handle region of Texas found themselves experiencing repeated failure on one of their 14 stage boiler feedwater (BB3) pumps. The pump had recently been modified by the supplier to provide a short-term solution. This in turn reduced the mean time between failure (MTBF) of the pump, requiring continued support and further analysis.

Combined cycle plants are comprised of both gas and steam power production technologies, capable of producing up to 50% more electricity than traditional simple-cycle plants. With the ever-increasing demand for energy, this technology is becoming increasingly relevant in throughout the pump industry. As such, it is highly important that these plants operate at peak efficiency.

Originally, the stationary inserts at several locations in the pump assembly were modified in such a way that increased the likelihood of friction and galling of the stationary and rotating parts of the pump assembly. The consecutive failures experienced on site were repeatedly of the same failure mode, which strongly points toward a pump design problem.

Read the full article at worldpumps.com

An Engineered Battle Against Cavitation

Impeller Cavitation

With inlet backflow recirculation present, the impellers were experiencing horrific vane breakage and cavitation.

A power station’s cooling water pumps were constantly being repaired, costing the plant millions of dollars in costs and service time due to the severe operational disruption and logistics required to remove and transport such large equipment. Previous attempts made by the station to improve the reliability of the impellers through upgraded material selections had little impact on reliability.

It was clear that something had to change as the station’s pump reliability was now a major financial focus. The many vane cracks, cavitation and broken vane sections that were weld-repaired during inspections throughout the pumps’ life cycles prompted the station to investigate a more permanent solution to the issue.

During the last repair, the reliability engineer inspected the impellers and found the cavitation was similar to those reported during prior repairs. An engineering repair company that specializes in fluid dynamics was asked to investigate the root cause of the continuing pump issues. The team conducted an investigation on the system layout and operation parameters.

The results of the forensic analysis showed that the impeller blades were suffering cavitation to the low-pressure side of the vanes. Additionally, the cavitation and cracked vanes toward the eye also indicated that the sizing of the inlet and its associated blade angles may be active factors in the repeated failures.

Read the full article at www.pumpsandsystems.com

Pump Renovation Restores Balance

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.

Weights added to impellers

Adding weights to impellers is generally not standard practice.

Where not to position the weights.

Where not to position the weights.

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