Tag Archives: centrifugal

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Meet Dr. Gary Dyson, Hydro’s Pumps & Systems Columnist

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Dr. Gary Dyson received his Ph.D. from Cranfield University and has spent his entire career specializing in rotating equipment. He has used his hydraulic expertise to help many customers re-engineer their equipment to improve reliability, performance, and efficiency.

Dr. Gary Dyson is now a regular columnist for the industry magazine, Pumps & Systems. In the past, he has written many articles for the magazine and now shares his wealth of knowledge on a regular basis.

To check out Dr. Dyson’s contribution to the magazine, click here.

For more information on how Hydro can reduce downtime and costs, visit us online here.

Wear in Centrifugal Pumps

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Illustration of wear at the volute lip.

Centrifugal pumps are sometimes used in environments where the pumped product contains suspended solids. While some pumps are specifically designed for solid handling or slurry applications, normal centrifugal pumps do not contain features to prevent performance degradation from the impact of solids.

There are a few key signs that a conventional centrifugal pump is suffering from erosive and abrasive wear. Here are assessment and mitigation strategies to be considered and applied when this occurs.

Particles are a problem in a centrifugal pump due to the way the machine adds velocity to the liquid as it passes up the impeller channels. In general, the higher the speed at the tip of the impeller, the more energy that is imparted to any particle that is suspended within the liquid. This energy can then cause damage to anything it impacts.

Source: https://www.pumpsandsystems.com/wear-centrifugal-pumps 

The Basics of Reciprocating vs. Centrifugal Pumps

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Image 1. A reciprocating pump’s fixed volume. Flow is determined by stroke, area and speed. (Images courtesy of Hydro)

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.

Authored by Gary Dyson.
Source: pumpsandsystems.com

Build your skills: View Hydro’s upcoming pump training seminars

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Interested in pump training? Hydro’s got you covered. Providing aftermarket-focused training is an important part of our commitment to our customers. We offer training on a range of topics from pump fundamentals to more specialized hands-on programs for high pressure multistage pumps.

Hydro’s training helps you do what you do – better. Visit our training page to view our upcoming seminars!

Pump Training Seminars | Hydro, Inc. from Hydro, Inc. on Vimeo.

Pump Renovation Restores Balance

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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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