The Basics of Reciprocating vs. Centrifugal Pumps

engineering column PD pumps Understanding the differences between these types of pumps can mean avoiding difficulties and reliability problems.

The demand for the duties that fall within the performance range of reciprocating pumps is rising. Process flows are falling while the pressures required are increasing.

Engineers are generally familiar with operating principles, performance curves and selection criteria for centrifugal pumps, but the training and knowledge around the operating principles of reciprocating pumps is not as common.

Unlike centrifugal pumps, reciprocating pumps have a stronger interaction with the system within which they sit. This is due to the pressure pulsations they generate.

If we think about any linear reciprocating motion of a piston, at some point the velocity of the piston is zero as it changes direction at the top and bottom of its stroke. This means that the pressure pulsations are much larger in a reciprocating machine than in a centrifugal machine.

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Asset Monitoring Improves Reliability & Visibility

Hydro remote condition monitoring A major pipeline transmission company found itself reconsidering the effectiveness of its maintenance strategy. The company faced a challenge: optimizing asset visibility and implementing remote condition monitoring of equipment health while avoiding a high-cost investment and installation disruptions.

This particular pipeline transfers a variety of products, ranging from gasoline to jet fuel, serving customers via pump stations and storage tanks across the United States. For this customer, it is imperative to ensure that pumping assets are efficient, reliable and safely maintained consistently. The pipeline supports the needs of more than 50 cities, thus making the pumping assets critical to the availability and overall operation.

Technology plays a vital role in day-to-day operations in supporting end user activities, ensuring strict safety regulations, optimizing maintenance and providing data on equipment health. In this case, the pipeline company wanted to significantly improve and innovate upon its current maintenance approach in two ways: by monitoring asset visibility in real-time and trending data for their critical pumping equipment.

Read the full article at pumpsandsystems.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

HydroTex Deer Park Service Center Relocating to La Porte, TX

The new 33,000 square building in La Porte, Texas.

HydroTex, a subsidiary of Hydro, Inc., announces the move of its Deer Park operation to a new 33,000 square foot building in La Porte, TX.

The new service center will offer expanded capacity for analysis, engineering, rebuilding and repair services for pump systems and rotating equipment as well as climate controlled storage of pumps and parts.

Located near the busy Houston Ship Channel, the new facility is ideally situated to serve the needs of surrounding industries using pumping equipment of any capacity. To learn more about the new facility or to schedule a shop visit, please contact HydroTex.

 

Source: pumpsandsystems.com

Middle East Power Plant Demonstrates the Advantages of Pump Health Audits

With the help of a field evaluation, plant managers avoided unnecessary pump repairs.

Written by: Gary Dyson & Thomas Arakal
Publisher: Pumps & Systems / December 2016

 

A decade-old, 1,000-megawatt (MW) combined cycle power plant in the Middle East called an equipment repair and engineering company to conduct a pump health audit. Given the age of the plant and the fact that none of the pumps had undergone a major overhaul, plant personnel asked the engineering firm to determine which pumps should be pulled for repair at the next scheduled outage. The equipment consisted of six condensate extraction pumps and six boiler feed pumps.

Leaving the production process undisturbed, the field pump health evaluation team conducted a non-invasive pump study. Flow, pressure, vibration, power consumption, temperature and other data were collected for all the pumps in various regimes of operation. A team of engineers analyzed and compared the results of the measurements to the original design parameters. The study’s conclusions and engineering recommendations were published.

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