The Basics of Reciprocating vs. Centrifugal Pumps

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

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.

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Engineering is at the Heart of Hydro Inc.’s Aftermarket Services

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.

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diagram, engineering drawing

Setting the New Pump Testing Standard

The pump industry faces a challenge in keeping up with changing efficiency regulations. Programs such as the Hydraulic Institute (HI) Pump Test Lab Approval (PTLA) are helping companies adhere to these standards. Here, we see how Hydro, Inc. made history with the first HI PTLA certification.

Written by: Michelle Segrest
Publisher: World Pumps / June 2016

 

With an engineering first approach, Chicago’s Hydro, Inc., proves the impact of redesigned and engineered pumps by testing their real-time hydraulic and mechanical performance at its state-of-the-art Test Lab. It is in the 46,000-square-foot- facility that Hydro develops and implements engineering modifications for improving the performance of critical pumps and then verifies that performance in the lab.

Thanks to high-quality capabilities in testing vertical, horizontal, and submersible pumps, Hydro made history in September 2015 by becoming the first recipient of full certification of the new Hydraulic Institute Pump Test Lab Approval program.

This new industry standard is designed to assist pump OEMs and other pump test laboratories to improve their current laboratory procedures and policies by working with a third-party auditor to develop and maintain accurate, uniform and repeatable pump testing protocols. The program also helps participating organizations adhere to the requirements of the international test laboratory accreditation standard (ISO 17025) concerning test measurement equipment.

“Hydro’s test lab is unique because it was designed to support the aftermarket by having the flexibility to test a wide range and variety of custom engineered pumps,” said George Harris, Hydro CEO and Founder. “Since it is not incorporated in a plant which manufactures new pump production, as is the case with many large OEMs, it is possible to test a customer’s pump in 1-to-3 weeks lead time. This is very important because customers who need a certified test, need the pump tested quickly.”

Since it opened in 2010, Hydro’s 5,000-Horsepower Test Lab has helped to troubleshoot problems with pumps in the field by isolating the pump from its system in a controlled environment to simulate field conditions in a safe manner.

“Hydro remains independent of the constraints that can be imposed by relying on existing hydraulic designs and manufacturers’ predicted performance curves,” said Jeff Johnson, Vice President, Hydro, Inc., a 41-year industry veteran who was instrumental in the design and construction of Hydro’s Test Lab. “All of these efforts ultimately lead to a more reliable and well understood pump performance.”

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Single-stage horizontal split case (BB1) pump test with customer motor – test loop.

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