by Lev Nelik, P.E., APICS, Pumping Machinery, LLC
Lev Nelik, or Dr Pump as he is also known, is an international pump industry stalwart with over 30 years of industry experience and over fifty publications about pumps to his name. In addition to his consulting work, he currently teaches pump training courses worldwide and publishes pump tips, advice and troubleshooting on his website. Much of his advice focuses on preventative maintenance methods to improve reliability, reduce energy consumption and optimise the operation of pump systems. In this article, we look at some of his top tips to ensure pump reliability.
There are a number of reasonably straightforward but highly effective things you can do to ensure efficient and reliable pump operation and realise substantial savings in the long term. Whether you’re new to the industry or just need a refresher after years working with pumps, these four tips are worth keeping in mind.
Tip 1: make sure your pump is running efficiently
By making sure pumps operate as efficiently as possible, we can make substantial energy savings and reduce running costs. While we often take pump efficiency for granted, many pumps actually operate inefficiently. Where a pump operates on its head-capacity curve, with regard to Best Efficiency Point flow (BEP), has a very significant impact on the pump energy consumption.
Many plant pumps no longer operate at BEP, for various reasons including changes in plant operation or wear on internal components.
But what is the best solution? Replacing an existing pump with one sized for the proper flow may work, but is often very expensive. Changing piping, if possible, is often even more costly.
A much more economical, expedient, and practical solution is to modify the internal hydraulics, by fitting the existing casing with a new impeller, specifically designed for the new required flow.
Tip 2: make sure your operators receive regular, hands-on training
For staff working on pumps to complete their jobs as effectively as possible they need to know pumps, not just theoretically, but on a practical, hands-on level. Pumps on the plant floor often don’t look exactly like those in a text book.
Even long-time staff may need training to keep on top of the latest technical advances in the field.
The hands-on experience of taking a pump apart, touching and feeling its internals, coupled with basic pump theory often achieves the best results.
It’s also a good idea to train staff from different areas of the company, rather than just maintenance. This helps operators and engineers better understand the consequences of their actions, such as pump flow control, energy consumption and reliability issues, which are not normally apparent sitting at the control room.
Tip 3: select a specialty material to help improve the efficiency and reliability of a multistage pump
When designing a multistage pump system, the materials used for various components can have dramatic impacts on the reliability and efficiency of the systems in the long term.
For instance, a huge variety of different materials can be used for pump bushings, including metals (bronze, hardened steels), hard coatings (which can be applied by many methods – fused deposition (cold or hot methods), laser treatment, nitriding, carburising, etc.), non-metals (thermoplastics, thermosets, composites), ceramics. All of them have benefits and shortcomings, such as resistance to temperature, thermal or mechanical shock, machinability, galling resistance, dimensional stability, swelling, chemical resistance, abrasive resistance and, of course, cost.
It is important to do your research and match the material used to the pump system application and the fluid being pumped. Desktop research alone may not be enough, it is worth talking to a range of interested parties in the field (such as material manufacturers, pump suppliers, and end users) and collecting feedback on their experiences.
Tip 4: check the fits and clearances of centrifugal pumps and drives
I recommend creating a robust schedule of preventative maintenance checks to keep centrifugal pumps and drives operating efficiently and to prevent faults before they occur.
These tasks can be divided by those that need to be checked daily (e.g. flushing pumps, checking for leaks, noisy cavitation, discolouration and temperature), monthly (e.g. refilling oil in bearing reservoirs, cleaning oiler bulbs, cleaning, replacing guards), six monthly (e.g. service standby pumps, apply rust preventative coating), yearly (e.g. inspect disc coupling for signs of wear and cracks, check coupling alignment, check axial float) and seasonally.
The exact schedule for your equipment will depend on factors such as your pump system, application and the nature of the substance being pumped.
Pump efficiency and reliability are too important to neglect until something is obviously wrong and should be in the minds of all those working with pumps. More articles about pumps and their maintenance can be found on Dr Pump’s website www.pumpingmachinery.com.
About Dr Pump
Dr Nelik has 30 years of experience with pumps and pumping equipment. He is a Registered Professional Engineer, has a Ph.D. in Mechanical Engineering and a Masters in Manufacturing Systems and is the author of articles, chapters and books about pumps. He is a President of Pumping Machinery, specialising in pump consulting, training, and equipment troubleshooting.
His experience in engineering, manufacturing, sales, field and management includes: Ingersoll-Rand (Engineering), Goulds Pumps (Technology), Roper Pump (Vice President of Engineering, and Repair/Overhaul) and Liquiflo Equipment (South-East Regional Sales Manager, and later a President). Dr Nelik is a Full Member of the ASME, and a Certified APICS. He teaches pump training courses and consults in the US and worldwide.