Click on the categories below to view the available tutorials
Basic Hydraulics - Centrifugal Pumps
Click on a topic below for a brief description of its contents.
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This
waterhammer
tutorial looks at the subject from a different
perspective than does my earlier one. Part 1
covers what? & why? while Part 2 looks the the
causes and variables. See my August &
September 2008 Pumps & Systems magazine articles
for additional reading.
When Bubbles Don't Burst - Why Cavitation is Damaging
This
tutorial
takes a look at cavitation from a different
perspective. It expands upon my original turoral
"Cavitation - A Largely Misunderstood Phenomenon.
Preservation of Efficiency - Affinity Revisited
In
"Centrifugal
Farce & Affinity" we took a look at the affinity
laws and showed how the predict pump performance when
its speed changes or its impeller is trimmed.
This tutorial goes a step further and describes the
effect of these changes on pump efficiency.
Net Positive Suction Head - NPSHa & NPSHr
This tutorial provides a simple yet detailed explaination of the components of NPSH. It also discusses their relationship to cavitation in a centrifugal pump. See my May 2008 Pumps & Systems magazine article for additional reading.
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Specific Gravity & Viscosity - Parts 1 & 2
Specific gravity and liquid viscosity affect centrifugal pump operation in very different ways. This two part tutorial discusses the impact of each. Part 1 covers SG while Part 2 looks at Viscosity. See my March & April 2009 Pumps & Systems magazine articles for additional reading.
Return to Titles Liquid
Friction - The Tarantino Effect
The
physics
of liquid friction is still pretty sketchy.
Unlike solid friction, velocity and surface area are
major considerations. This tutorial compares
these two forms of friction and goes into some detail
about each.
Centrifugal
force
is a farce! It is all about the velocity added
by a pump's impeller. This tutorial dispells
this myth and explains the relationship of velocity to
the three affinity laws.
Wire to
Water Energy Calculator
This Excel based calculator allows you to compare the energy consumption of two different pumps based upon hydraulic and motor efficiency. It computes annual operating costs for both and the payback period for the more efficient system. See my March 2001 Pumps & Systems magazine article for additional information.
Return to TitlesSystem Energy Calculator
This
Excel
based calculator allows you to compare the energy
consumption of two pumps operating under different
system conditions. It computes annual operating
costs for both and the payback period for the more
efficient system. The example included is for a
pump that is pumping 600 GPM through 600 feet of 6"
and 8" steel pipe.
Off BEP Energy Calculator
See
my January 2012 Pumps & Systems article for
information on this calculator.
Basic Hydraulics - Displacement Pumps
Click on a topic below for a brief description of its contents.
Positive Displacement Pumps - Part 1 Reciprocating Pumps
Positive Displacement Pumps - Part 2 Rotary Pumps
Viking Pump Company - PD Pump White Papers
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Other Pump Topics
Click on a topic below for a brief description of its contents.
Constant Pressure Booster Systems
The Self Priming Pump
How Curve Shape Can Influence Pump Selection
Siphons & the Siphon Effect - That Sucking Sound
Pascal's Principle - Paradox Lost
Parallel Pumping - Parts 1 & 2
Two Steps to Longer Pump Life - Parts 1 & 2
Centrifugal Pump Operation at Off Design Conditions - Igor Karassik
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Centrifugal Pump Operation at Off Design Conditions - Parts 1 - 3
In the mid eighties, Igor Karassik wrote a three part series that described the problems associated with off BEP operation. Part 1 explores radial thrust and temperature rise while Part 2 looks at internal recirculation and air binding. Part 3 discusses discharge recirculation and discharge bypasses. All are written in a very understandable manner which is the goal of Pump Ed 101. These are scanned files and the resolution is not very good. In your Acrobat tool bar, increase the page size to 130% for an easier read.
Download Part 1
Download Part 2
Download Part 3
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Two Steps to Longer Pump Life - Parts 1 & 2
This tutorial explores the two most important preventive maintenance steps that influence pump and motor life. Part 1 looks at off BEP operation and outlines how to determine the "as built" operating point. Part 2 investigates current unbalance and the corrective measures that should be taken.
Download Part 1
Download Part 2
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Parallel Pumping - Parts 1 & 2
Sometimes the flow and head of two pumps operating in paralle is not what we expect it to be. This tutorial takes a look at the performance of identical and dissimilar pumps and the effect of the system curve. Part 1 compares the pumps and Part 2 factors in the system curve.
Download Part 1
Download Part 2
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Pascal's Principle - Paradox Lost
The pressure exerted by a colum of water depends upon its density and hight - - it has absolutely nothing to do with the its volume. In this tutorial we take a close look at this paradox and provide various examples that support Pascal's Principle.
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Siphons & The Siphon Effect - That Sucking Sound
In this turorial we explain how a pipeline siphon works and provide several examples of how they can affect pump performance.
Download
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How Curve Shape Can Influence Pump Selection
Some pump curves are very steep while others are pretty flat. And, ofcourse there many inbetween. This turorial looks at how the shape of a performance curve can influence a pump's performance in a particular application.
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Sewage & Wastewater
Click on a topic below for a brief description of its contents.
Air vs Oil Filled Sewage Pump Motors
Sewage Pump Impeller Selection
Vortex Action - How Lower Efficiency Can Reduce Cost
Lower Flow Nonclogs - Solids Handling Options
Pressure Sewer Systems
Lift Station Maintenance
Pump Cycle Time Calculator
Wastewater Pump Draw Down Calculator
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Pump Start and Cycle Time Calculator
See my April 2010 Pumps & Systems article for a description of this calculator.
Download excel xlsx
Download excel xls
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Lower Flow Nonclogs - Solids Handling Options
There are times when pumps installed in lower flow applications need the ability to pass a full 3" spherical solid. Should you install a 4" pump and run to the left of the performance curve? Probably not. This tutoral provides several options that will enhance pump life.
Download
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Vortex Action - How Lower Efficiency Can Reduce Cost
Vortex pumps have a bad reputation in the engineering community because of their low hydraulic efficiency. It turns out that their lower maintenance will often substantially reduce overall operating costs even though electrical costs may be slightly higher. This tutorial explains vortex action and provides several examples that show why this type of pump may be a better choice.
Download
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Variable Speed Pumping Systems
Click on a topic below for a brief description of its contents.
Variable Speed Pump Selection - Parts 1 - 3
This tutorial takes a different approach to pump selection for VFD operation. Part 1 addresses constant pressure / variable flow while Part 2 addresses variable pressure / variable flow. Part 3 adds an elevation or constant pressure component to variable pressure / variable flow.
Download Part 1
Download Part 2
Download Part 3
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Lift Station Level Control - Almost Utopia
Back in the old days level control had nothing to do with saving energy. In fact it was often a necessary evil. With the advent of the VFD you may be able to achieve relatively constant flows and reduce the energy required. This tutorial investigates the possibilities.
Download
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Comparing Energy Consumption - To VFD or Not to VFD
If the goal of your VFD application is to reduce energy consumption, you have to do a careful comparison between VFD and constant speed operation. This tutorial uses a constant pressure application to show you the proper way to do that comparison.
Download
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Variable Frequency Control - Other Advantages
VFD's can reduce energy consumption by allowing a pump to run at the duty point required by the system and it can change that duty point in real time. But they offer several other advantages that can often justify their use even if pump speed is not varied. This tutorial explores those other advantages.
Download
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Balancing Voltage & Frequency - Fluxuating Flux
We all know that a VFD varies the frequency seen by an electric motor. That is how it varies the motor speed. But, did you know that it must also vary the voltage? If it did not, the magnetic field produced by the stator would become saturated and torque would become unreliable. This tutorial explains the volts / hertz relationship that must be maintained by the VFD.
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Resonant Frequency & Critical Speed
The vibration that occurs in a pumping system due to resonance is not a good thing. Resonance arrises when a variable speed pump reaches a critical speed. It turns out that the first or lowest critical speed can be easily calculated from simple data provided by the manufacturer. This tutorial explores resonant frequency and shows how to calculate the speed that causes it.
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Pump Evaluation, Selection & Testing Tools
Click on a topic below for a brief description of its contents.
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Parallel Pump Performance Analyzer (12/13)
PPPA provides both across the line and variable speed analysis of up to eight pumps running in parallel. See my December, 2013 Pumps & Systems article for a full description of its capabilities.
Download excel xlsx
Download 50 Hz Version excel xlsx
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Pump Field Test Calculator
The 2013 version of my field test calculator allows detailed testing of pumps in the field. There are four different tabs that directly address testing of above ground centrifugals (suction & discharge gauge method), submersible wastewater (discharge gauge method) and lineshaft turbines (discharge gauge method). After entering the required data the calculator will calculate velocity, velocity head, TDH, average voltage, average current, unbalanced voltage and current, water HP, test point HP, pump efficiency and the cost per 1000 gallons pumped. If multiple points are tested an H/Q test curve is generated automatically on page 3. All equations used for calculations are shown on the spreadsheet. Complete instructions are included. See my Jan 2011 and May 2014 Pumps & Systems articles for more information.
Download excel xlsx
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Submersible Motor Flow Velocity Calculator
This simple calculator allows you to enter the motor OD and casing ID for a submersible well pump application. It then calculates the flow velocity past the motor, the effective flow ID and the friction per motor foot.
Download excel xlsx
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Wastewater Pump Draw Down Calculator
Draw Down is a common technique for evaluating wastewater pump performance. This simple, Excel program standardizes the measurement process and also calculates TDH. Both flow and TDH are required to evaluate pump performance and locate the operating point on the pump H/Q curve. Discharge velocity head is also calculated and included in the TDH calculation. See my December 2011 Pumps & Systems article for more information. The Drawdown combo calculator is designed for older wells that use a partition to accommodate both wet and dry pits in the same well. A drawing on the sheet explains their use.
Drawdown excel xlsx updated 12/13
Drawdown combo excel xlsx updated 12/13
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Pump RPM, Hertz, Impeller Trim & Pulley Calculators
These four calculators use the affinity laws to calculate changes in pump flow, head & BHP based upon changes in pump speed or impeller diameter. Follow the directions for data entry and then click on the tabs to view the H/Q curves. (These calculators were updated on 11/17/12. The origional versions were test versions that were uploaded accidentally. If you downloaded the calculators prior to 11/17/12, you should replace them with the current ones.)
RPM Calculator excel xlsx
Hertz Calculator excel xlsx
Trim Calculator excel xlsx
Pulley Calculator excel xlsx
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Pump Start and Cycle Time Calculator
See my April 2010 Pumps & Systems article for a description of this calculator
Download excel xlsx
Download excel xls
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Pump & Motor HP At Lower Frequencies
When pump speed is reduced, the required HP reduces as the cube of the change in speed. When a VFD reduces motor speed the available HP is also reduced. In cases where lower HP motors are used to run a pump at some maximum frequency, it is important to make sure that the HP available at that frequency is sufficienct. This calculator will show you the required vs available HP. See my January 2013 Pumps & Systems article for more information.
Download excel xlsx
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Pipe & Fitting Friction Calculator
There are many online friction calculators available but, there are times when you cannot go online to use them. Although not as comprehensive as some of the online versions, this calculator allows you to compute the friction for up to three piping segments. It also allows you to select the valves and fittings for each segment.
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Lots of Pump & Motor Stuff Calculator
This calculator allows you to compute lots of pump and motor stuff from catalog and field test data. On the pump side it computes specific speed, suction specific speed, min & max acceptable flow, actual pump efficiency and cost per 1000 gallons pumped just name a few. On the motor side it computes HP, torque, kVA, power cost per hour, voltage unbalance and current unbalance just to name a few. It also includes a simple pipe friction calculator. You will have to check it out to see the rest.
Download excel xlsx
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Confusing Units of Measure - Work, Power, & Torque
This tutorial could be located under other categories because it applies to all rotating machinery. It compares the units of measure, used in a rotational environment, with their linear cousins. Hopefully it makes them a little more understandable.
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Inertia - Confusing Units Revisited
Rotational inertia is quite different than its linear cousin but there are times when we need to understand its relationship with torque. This tutorial investigates rotational inertia, compares it with linear inertia, and uses some simple examples to show the effects of its contributors.
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Process Control - Parts 1 & 2
This two part tutorial attempts to make process control understandable. Part 1 takes a look at very simple control algorithms while Part 2 investigates the more complex PID control used in VFD applications. Also see "PID Control" under the Variable Speed section for another approach.
Download Part 1
Download Part 2
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Power Factor - Parts 1 & 2
This tutorial takes a detailed look at the cause and effects of PF. Part 1 (Electricity Behaving Badly) explains PF and it causes. Part 2 (Electricity Behaving Better) investigates potential fixes and shows their effect.
Download Part 1
Download Part 2
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VAST (Various And Sundry Things)
Click on a topic below for a brief description of its contents.
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The tutorials and topics presented
here were developed over the past twenty years. Several
were written for my own employees in an effort to further
their understanding of the equipment and applications that
were our life's blood. Others were written specifically
for specifying engineers so that they could gain an unbiased
understanding of different options. But, most were
developed to provide information for the overall pump
community. So far, they have been well received and I
have shared them via one web site or another since 1997.
Many emails from around the world have offered
compliments, corrections, and suggestions. Please keep
them coming.
Some are short and simple -- "The
Self Priming Pump", for example, gives a brief overview of
self priming pumps and the applications for which they are
intended. These will usually reference another tutorial
for more detailed study. Others, like "AC Power", are
far more detailed and present a thorough overview from
generation to consumption. "Hertz" and "HPSA", on the
other hand, are designed to be interactive learning and sizing
tools. "Centrifugal Pump Dynamics" is html based and
uses animations to get its points across. My "Pumps
& Systems" magazine articles offer a short review of a
broad range of pump, motor and control topics. Some of
the "two part" articles, such as "Power Factor" provide an in
depth review.
The "Puzzler" is a totally different
animal. It uses the findings of simple Physics to help
explain some of the every day and, even more complex phenomena
that we encounter in pumping applications. I
developed the Puzzler as the basis for my weekly "lunch &
learn" seminars that I presented to my employees. The
beauty of the "Puzzler" is that it promotes learning rather
than memorization. For example, why memorize a fact such
as -- the head produced by a centrifugal pump changes as the
square of a change in speed -- when the "falling body"
equation shows you why?
If you have questions or
suggestions, please drop me an email.
Joe Evans
Have you ever wondered why the pressure of a fluid flowing in a pipe decreases as its velocity increases? Could it have something to do with why airplane's fly? Why does 115 volts plus 115 volts equal 230 volts in some cases, but only 208 volts in others? Doesn't the pressure that a liquid exerts have anything to do with its volume? When is a watt not a volt-amp? Is centrifugal force really a farce? How come liquid friction, but not solid friction, is affected by velocity and surface area?
If you find these and other questions relating to pumps, motors, and electricity especially titillating, you are going to love the Puzzler. The Puzzler poses a pointed question, but that question is just the tip of the iceberg! The discussion that follows explores not only the question but also the physics surrounding it.
The current Puzzler Series consists
of more than forty brain teasers designed to expand your
knowledge of mechanics, hydraulics, and electricity. The
dowload button is below the titles.
|
Basic Puzzlers The Restricted Pipe Puzzler (Bernoulli Principle) The Water Column Puzzler (Hydrostatic Paradox) The Sinking Float Puzzler (Buoyancy) The Barrel Burst Puzzler (Pascal’s Experiment) The False Force Puzzler (Centrifugal Force) The My Shaft’s Bigger Than Yours Puzzler (Torque) The WK2 Puzzler (Inertia) The Belt Tightening Puzzler (Mechanical Friction) The Warranty Puzzler (Time Dilatation) The Water Supply Puzzler (Exponential Function) Hydraulic Puzzlers The Affinity Puzzler
(The Affinity Laws) |
The Worn Pump Puzzler ( Axial & Radial Thrust) The Differing Pressure Puzzler (Eductors) The Corrupted Curve Puzzler (Positive Displacement Pumps I & II) The Leaking Pump Puzzler (Hydraulic Ram) The Air Lock Puzzler (Siphon) The Drawdown Puzzler (Hydropneumatic Tanks) The Priming Puzzler (Centrifugal Pump Priming) The Suction Air Puzzler (Pipeline & System Air) Electrical Puzzlers The Mumbo-Jumbo Puzzler (Motor Insulation) The Right Motor Puzzler (Service Factor) The Kill A Watt Puzzler (Reactance) The Starting Puzzler (Motor Starting Techniques) The Changing Voltage Puzzler (Three Phase Connections) The Distorted Wave Puzzler (Harmonics) The Syntax Puzzler (Boolean Logic) The Grounded Pump Puzzler (Corrosion Protection) The Country Boy Puzzler (Phase Generator) The 4” Motor Puzzler (Tesla Meets Newton) |
Download The Complete Puzzler Series (918 K Acrobat Document)
A BRIEF
INTRODUCTION TO CENTRIFUGAL PUMPS - Joe Evans, Ph.D
Download ( 1001 K Acrobat Document)
CONSTANT
PRESSURE
BOOSTER SYSTEMS -
Joe Evans, Ph.D
This
tutorial will allow you to enter the realm of constant
pressure and the booster systems that support it.
It starts with a brief overview of the
differential pressure booster and then takes a look at
PRV controlled simplex, duplex, and triplex constant
pressure systems. From there it moves on to VFD
control and the advantages it can offer. Topics
covered include tank vs tankless systems, sequencing,
pressure vs flow control, and pump selection. If
you are unfamiliar with the VFD, download "Variable
Frequency 101" as you will need an understanding
of their operation for the second half of this
discussion.
Download
( 263 K Acrobat Document)
This brief overview discusses the advantages and limitations of self priming centrifugal pumps. It also references a "Puzzler" for a more detailed understanding of centrifugal pump priming.
Download ( 108 K Acrobat Document)
THE AC
INDUCTION MOTOR - Joe Evans, Ph.D
This
introduction is intended for those with little or no
background in electric motors. It begins with the very
basics including magnetism, direct current, and the
operation of a simple DC motor. From there it moves on
to alternating current, induction, and the operation of
a simple AC motor. It concludes with a discussion of
work, torque, and horsepower. It is an excellent primer
for some of the electrical "Puzzlers". For a more
comprehensive review of induction motors, see my five
part series (March - July 2011) on the "Pumps &
Systems Magazine Columns" page of PumpEd101.
Download ( 422 K Acrobat Document)
THE
SINGLE PHASE
INDUCTION MOTOR - Joe Evans,
Ph.D
The major difference in single and three phase motors is that the single phase motor requires some sort of starting mechanism to get it rotating. This overview looks at four of the most popular starting (and two running) techniques and the pros and cons of each. It also includes a discussion of single and three phase rotational fields. It is aimed at the pump professional who works with single phase submersible wastewater pumps, well pumps, and small centrifugals. For a more comprehensive review of induction motors, see my five part series (March - July 2011) on the "Pumps & Systems Magazine Columns" page of PumpEd101.
Download ( 547 K Acrobat Document)
Why is AC power the
standard in the US? What is the difference between
single phase and three phase sine waves? Why does a
voltmeter read 115V, 230V, or 460V when the actual voltage
is quite a bit higher? How does a transformer work?
What is the difference between Wye & Delta versions?
Do resistive and inductive circuits behave
differently? What is power factor and what does it
have to do with reactance? How can capacitive
reactance be used to correct the problems caused by
inductive reactance? This short course is designed for the
pump professional who wants to gain a basic understanding of
AC power and its application to electric motors. See my
June through September 2010 Pumps & Systems magazine
articles for additional reading.
Download ( 397K
Acrobat Document)
VARIABLE FREQUENCY 101 -
Joe Evans, Ph.D
Why not debunk some of those myths surrounding VFD's and learn how simple they really are. Did you know that they have been around, in one form or another, since the invention of the AC induction motor? This short introduction will help the pump professional gain an understanding of their inner workings, potential problems, and some of the applications for which they are well suited. Topics include: the relationship between frequency and motor windings (poles), Pulse Width Modulation (PWM) output, effective voltage, insulation stress, harmonics, bearing damage, and typical applications in the pumping environment.
Download (368 K Acrobat Document)
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CENTRIFUGAL PUMP MOTOR SELECTION,
INSTALLATION, & START UP - Joe Evans, Ph.D
The vast
majority of failures of new electric motors can be
attributed to improper selection, installation, and start
up. Although factory defects do occur, they are rare and
are quite apparent upon tear down and inspection. This short
publication is a guide to the proper selection,
installation, and start up of new and replacement
centrifugal pump motors. (This tutorial was updated on
2/12/06)
Download ( 35 K Acrobat Document)
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RESONANT FREQUENCY
The
resonant frequency of and object is the frequency at which
it begins to vibrate of its own accord. In this
demonstration, by the University of Michigan Physics
Laboratory, sound waves are porduced at various
frequencies and projected upon a wine glass. A
strobe light allows us to view its vibrations and eventual
shattering. Download "Variable Frequency 101" for a
detailed explaination of resonant frequency and its
potentially damaging effect upon pumps.
Download ( 3.48M Quick Time Movie)
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AIR VS OIL
FILLED SEWAGE PUMP MOTORS - Joe Evans, Ph.D
Some manufacturers believe that filling a motor with oil is the only way to go while others think air to be a better solution (pun intended). This paper takes an honest look at these two popular submersible sewage pump motor designs and compares the advantages and disadvantages of each. Topics covered include motor efficiency, heat transfer, bearing lubrication, maintenance, and environmental concerns.
Download (235K Acrobat Document)Return to Titles
SEWAGE
PUMP IMPELLER
SELECTION -
Joe Evans, Ph.D
This overview discusses the various impeller designs used in raw sewage pumping applications. Designs covered include the major members of the radial vane family, the vortex impeller, and the centrifugal screw. Topics include centrifugal impeller basics, design pros & cons, operational characteristics, and application selection criteria.
Download
(339K Acrobat Document)
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PRESSURE SEWER SYSTEMS: CENTRIFUGAL
VS POSITIVE DISPLACEMENT - Joe Evans, Ph.D
During the past thirty years, low pressure grinder pump sewer systems have become a popular alternative to traditional gravity systems. The two basic pump designs, centrifugal and positive displacement, used in these systems are as different as night and day. This short article discusses the operating characteristics of centrifugal and positive displacement grinder pumps when installed in a pressure sewer system. Topics covered include pipeline velocity, unvarying vs dynamic flow, self limiting system pressure, operating power, and impeller / cutter design.
Download
(115K Acrobat Document)
HERTZ: A VARIABLE FREQUENCY / SPEED
CALCULATOR AND PLOTTING TOOL - Joe Evans, Ph.D
Hertz is an Excel program that allows you to illustrate the laws of affinity, perform a design point calculation, and plot centrifugal pump performance curves as a function of frequency or RPM. It is named for the German physicist, Heinrich Hertz, who discovered the very low frequency electromagnetic radiation we now call radio waves. After many decades of cps (cycles per second) we are finally giving him credit.
Directions
for
its use can be found at the bottom of the spread sheet.
"Auto Plot" automatically plots the 60, 55, 50, 45,
40, 35 and 30hz performance curves (in feet and PSI)
for the data you entered. You can also enter a
system curve so that you can evaluate your selection.
Instructions for custom plots are also included.
Download
(115K Excel Document)
Variable Speed Pump Analysis - Joe Evans, Ph.D
Variable Speed Parallel Pump Control Analysis - Joe Evans, Ph.D
CPSA: Centrifugal Pump Selection Assistant - Joe Evans, Ph.D
CPSA
is
an abbreviated and simpler version of Hertz but, also has
some additional features. It plots a system curve
and the 60 - 30 hz curves (in feet and PSI) for the
pump selected. There is nothing else to muddle the
picture and there is no need to scroll side to side or up
and down. It also asks for the hydraulic
efficiencies for each of the flow points and, in return,
prints the HP required as "data lables" on each of the
frequency curves. This allows you to quickly
determine the power savings for an application using a
given pump.
Download (121K
Excel
Document)
VSPA-50: Variable Speed Pump Analyzer 50hz - Joe Evans, Ph.D
VSPA-50 is an international version of CPSA. It plots a system curve and the 50 - 25 hz performance curves (in any unit of measure). It can accomodate up to eight H/Q points. If you enter the power requirement for each of the flow points for the 50hz curve, it will generate "power data lables" on each of the frequency curves. This allows you to quickly determine the power savings for an application using a given pump. See my May 2009 Pumps & Systems magazine article for additional information.
Download
(116K Excel Document)
VSPA-60: Variable Speed Pump Analyzer 60hz - Joe Evans, Ph.D
VSPA-60 is an international version of CPSA. It plots a system curve and the 60 - 30 hz performance curves (in any unit of measure). It can accomodate up to eight H/Q points. If you enter the power requirement for each of the flow points for the 60hz curve, it will generate "power data lables" on each of the frequency curves. This allows you to quickly determine the power savings for an application using a given pump. See my May 2009 Pumps & Systems magazine article for additional information.
Download
(116K Excel Document)
Radial Thrust Calculator - Joe Evans, Ph.D
The unbalanced radial thrust that arises in a single volute pump is lowest at or near BEP depending upon the Pump's Specific Speed (Ns). But as operation moves away from BEP (especially to the left) the net radial thrust increses quickly. Unbalanced radial thrust can cause increased shaft deflection which can lead to increased seal, bearing, and wear ring wear. In some cases it can cause the shaft to break. This calculator allows you to quickly calculate the radial thrust in PSI at any point on a pump's H/Q curve. See my Jan 2010 Pumps & Systems magazine article for additional information.
Download
(58K Excel Document .xlsx)
Download (58K Excel Document .xls)
Return to TitlesSuction Calculators - Joe Evans, Ph.D
Two useful pieces of information that can be used to identify pumps that are prone to cavitation due to suction recirculation are Suction Specific Speed (S) and Suction Energy (SE). This calculator will allow you to calculate both. For more information on S see Terry Henshaw's Oct - Dec 2009 Pumps & Systemsarticles on NPSH and Suction Specific Speed. You can read them at www.pump-zone.com. See my Feb 2010 Pumps & Systems magazine article for additional information. The calculators were updated on 3/31/11.
Download (2.4M Excel Document .xlsx)
Download (480K Excel Document .xls)
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CONVERT: A DESKTOP CONVERSION UTILITY
It was eveloped by Josh Madison ( http://www.joshmadison.com/software/convert/ )
Download (156k WinZip file - unzips to a 548k exe file)
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VFD Pump Selection - Constant Pressure - Joe Evans, Ph.D
Download (215K Acrobat Document)
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VFD Pump Selection - Variable Flow / Variable Pressure - Circulation - Joe Evans, Ph.D
Download (183K Acrobat Document)
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VFD Pump Selection - Level Control - Joe Evans, Ph.D
Download (232K Acrobat Document)
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TDH Calculator - Domestic Submersible Well Pumps - Joe Evans, Ph.D
Download (54K Acrobat Document)
Download (Excel Spreadsheet)
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Lift Station Maintenance for the Complete Idiot - Steve Cottrell, Enco Southwest Inc.
Don't let the title offend you (Dummies was already taken). Steve's guide is written for that building maintenance guy who wakes up one morning and finds that he now has responsibility for a submersible lift station! It is simple, straight forward and will keep that station up and running.
Download (1120K Acrobat Document)
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Centrifugal Pump Intro for PP (Part 1 Elementary Mechanics & Hydraulics) - Joe Evans, Ph.D
This Power Point presentation is designed for audiences with a "limited" knowledge of centrifugal pumps. It can be presented in as little as an hour or as a morning or afternoon class if you go into more detail. Use the script to guide you through the slide show. Don't have Power Point on your PC? No problem - - download the pdf version and show it as slides on a PP projector or TV monitor.
As the title implies, this tutorial presents the basic mechanics and hydraulics of centrifugal pump operation. It begins by dispelling the myth of "centrifugal force" and shows that acceleration of a fluid is its sole purpose. It then moves on to a discussion of the pump "curve" and shows examples of series and parallel operation. It touches on specific gravity and why we typically rate pump performance in feet of head. We review the laws of affinity and illustrate them with a pump operating under VFD control. We finish with a discussion of suction conditions and liquid friction.
Download (707K Power Point) DownLoad (177K pdf Version) Download (92K pdf Script)
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WWPSA A Variable Frequency Sizing Tool - Level Control - Joe Evans, Ph.D
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Cavitation - A Largely Misunderstood Phenomenon - Joe Evans, Ph.D
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About the Author
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The Cowern Papers
Ed Cowern received his BS in Electrical Engineering from MIT and is a district manager for Baldor. His clear and understandable technical papers on electricity and electric motors make them a very useful reference.
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Web Site Development & Hosting
Pueo Advanced Media
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Why Newton Invented Calclus - Joe Evans, Ph.D
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Three Phase Motor Starting Techniques - Joe Evans, Ph.D
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Positive Displacement Pumps - Parts 1 & 2 - Joe Evans, Ph.D
Part 1 of this tutorial covers reciprocating designs while Part 2 deals with rotary units.
Download (Part 1 - 187k Acrobat Document) Download (Part 2 - 138k Acrobat Document)
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Viking Pump PD Pump White Papers
In the mid 80's Viking Pump Company published a couple of very useful white papers for positive displacement pump users. AD-19 was all about NPSH while AD-6 covered pressure and vacuum. Both are available below in pdf format.
Download AD-19 2 mb pdf
Download AD-6 2 mb pdf
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Sizing Pumps After Sunset - Joe Evans, Ph.D
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Background Image - Impellers
The background on my home page is one I developed for my first web site in the mid 90's. It provides a bit of pump based art work without detracting from the content. Below are a couple of images of the area where I live. Mt. Hood is a dormant volcano that last erupted in 1907 and is the second most climbed mountain in the world. It is surrounded by the 1.2 million acre Mt. Hood National Forest which has over 1200 miles of hiking trails. Most importantly, it is in my back yard! The image on the left is the North side as seen from Lost Lake. The one on the right is the Sandy river which originates in
the glaciers and runs through our community.
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Series / Parallel Pumping Analyzer with Autoplot - Joe Evans, Ph.D
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Centrifugal Pump Efficiency - What, How, Why, When ? - Joe Evans, Ph.D
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Waterhammer - Its All About Conserving Energy - Joe Evans, Ph.D
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Educational Seminars & Training
The seminars shown below have been presented to a wide range of audiences over the past twenty years. They are updated continuously and the current Power Point versions include lots of Java based animations that can often clarify many of those, otherwise, subtle points. My audiences include engineering firms, refineries, utilities, AWWA, WEF, MEA, NGWA, RWA, and other pump oriented organizations. Drop me an email if you are interested in an on site seminar or have questions.
Click below to download the pdf that describes the seminars that are approved for CEU credits in Oregon, Washington & Idaho. Depending upon the acrediting agency, presentations must be a minimum of one or three hours. Half day seminars can be a mix of various one hour presentations. Seminars are sponsored by PumpTech and can be presented in Washington, Oregon, Idaho and parts of Montana.
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Centrifugal Pump Dynamics - Joe Evans, Ph.D
Dynamics Html Version Dynamics Acrobat Version (98k pdf file)
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Anti VFD (Beware of the Nazi's)
As you search the web for more information on variable frequency applications you might get the feeling that we have reentered the era of pre WWII. Some of the sites out there profess that VFD's have no rightful place in our society and that there is no pump application worthy of their use. Most of these opinions come from those who offer competing products and they will show a pump curve or power analysis that proves that their product can always do a better job. I have even read some tax payer sponsored research that goes way over the line. One concluded that magnetic coupling systems offer power savings similar to that of VFD's. This certainly may be true in some instances but, the data used in this particular study was so skewed even Enron would have been concerned !
The same thing can happen on the other side of the aisle - - but it is usually due to a lack of knowledge rather than deceit. Many of the VFD articles in the trade press tend to be written by VFD manufacturers. And, although they have some pretty smart people, most have a limited knowledge of pump applications. Therefore the examples given tend to be more theoretical than practical.
Here is a good rule of thumb: no single application control technique will always be the best choice for a given application. If someone tells you that theirs is always best - - take them off your "favorites" list. In my variable frequency tutorials, I try to use pump curves that are more typical rather than one that is "perfect". This allows you to compare application results in a more realistic light.
PID Control - What, Why, How ? - Joe Evans, Ph.D
The P (proportional) in PID is not too frightening but, what about those other two letters? Are not the integral and derivative parts of that mathematics known as calculus? And, isn't calculus frightening? Well fear no more because this "layman's" discussion of PID control will help you understand what it is, why we use it, and how it works. We start with a discussion of open and closed loop control and give examples of each. We then move on to proportional control and the applications it supports. We end with a discussion of the integral and derivative functions and how they can temper the, sometimes, unruly nature of the proportional controller. Another discussion of this topic can be found in the "Pumps & Systems" section of this site.
Variable Fixed Speed Control - Float Switch Activation - Joe Evans, Ph.D
So, your waste water application will not lend itself to level control operation. Or, maybe you just prefer float switches over transducers and ultrasonic devices. Whatever the reason, VFS or variable fixed speed control might be a viable alternative to that pump down application. Today you can combine an inexpensive VFD with standard float switch technology and get a multispeed pumping system that can increase application flexibility and efficiency. This short tutorial takes a look at VFS control and how it compares to standard pump down applications.
SDSCA - Simplex / Duplex System Curve Analyzer - Joe Evans, Ph.D
There can be times when we over estimate the flow expected during parallel operation of two non-clogs. SDSCA is an excel spread sheet that allows you to analyze the operation of the same non-clog running under simplex and duplex (parallel) operation. It will generate a system curve based upon the information entered and give you the head required at design flow. You can then enter the curve data for a selected pump and the simplex and duplex operational curves will be plotted against the system curve. Scroll down for detailed instructions. The data used in the example can be found under the "Notes" tab.
Pumps & Systems Magazine Columns - Joe Evans, Ph.D
In September of 2006 I began contributing a monthly educational column to Pumps & Systems Magazine. The unedited versions will be available here in pdf format as they are published. Some of these columns are also listed under the proper category on the home page and include a short description. Most, however, are not so be sure to browse through all of the titles below. If you do not already subscribe to P & S you can do so online at http://www.pump-zone.com/
Nov 2006 - Preservation of Efficiency - Affinity Revisited Dec 2006 - Liquid Friction - The Tarantino Effect
Jan 2007 - When Bubbles Don't Burst - Why Cavitation is Damaging Feb 2007 - Pascal's Principle - Paradox Lost
Mar 2007 - Balancing Voltage & Frequency - Fluxuating Flux Apr 2007 - Comparing Energy Consumption - To VFD or Not to VFD
May 2007 - How Curve Shape Can Influence Pump Selection Jun 2007 - Power Factor Part 1 - Electricity Behaving Badly
July 2007 - Power Factor Part 2 - Electricity Behaving Better Aug 2007 - Vortex Action - How Lower Efficiency Can Reduce Cost
Sept 2007 - Lift Station Level Control - Almost Utopia Oct 2007 - Confusing Units of Measure - Work, Power, & Torque
Nov 2007 - Siphons and the Siphon Effect - That Sucking Sound Dec 2007 - Variable Frequency Control - Other Advantages
Jan 2008 - Process Control Part 1 - Smart and Not So Smart Control Feb 2008 - Process Control Part 2 - Even Smarter Control
Mar 2008 - Parallel Pumping Part 1 - Parallel and Not So Parallel April 2008 - Parallel Pumping Part 2 - Other Considerations
May 2008 - Net Positive Suction Head - NPSHa & NPSHr June 2008 - Two Steps to Longer Pump Life - Part 1
July 2008 - Two Steps to Longer Pump Life - Part 2 Aug 2008 - Waterhammer - Part 1 What & Why
Sept 2008 - Waterhammer - Part 2 Causes & Variables Oct 2008 - Lower Flow Nonclogs - Solids Handling Options
Nov 2008 - Variable Speed Pump Selection - Part 1 Cp-Vf Dec 2008 - Variable Speed Pump Selection - Part 2 Vp-Vf
Jan 2009 - Variable Speed Pump Selection - Part 3 Vp-Vf (+Cp) Feb 2009 - Resonant Frequency & Critical Speed
Mar 2009 - Specific Gravity & Viscosity - Part 1 April 2009 - Specific Gravity & Viscosity - Part 2
May 2009 - Variable Speed Performance Analyzer - 50hz June 2009 - Inertia - Confusing Units Revisited
July 2009 - Why The Left Can Be Dangerous Aug 2009 - Planning for System Growth
Sept 2009 - PD Pump Hydraulics - Part 1 Reciprocating Oct 2009 - PD Pump Hydraulics - Part 2 Rotary
Nov 2009 - Corrosion - A Natural Process Dec 2009 - Magnetic Couplings - Extra Benefits
Jan 2010 - Radial Thrust Calculator Feb 2010 - Suction Calculators
Mar 2010 - Energy Calculator April 2010 - Cycle Time
May 2010 - BEBOP June 2010 - AC Power - Part 1
July 2010 - AC Power - Part 2 Aug 2010 - AC Power - Part 3
Sept 2010 - AC Power - Part 4 Oct 2010 - VFD Parallel Pump Analyzer
Nov 2010 - Coating & Restoration - Part 1 Dec 2010 - Coating & Restoration - Part 2
Jan 2011 - Variable Speed Pump Analysis Feb 2011 - Testing Pumps in the Field
Mar 2011 - AC Motors Part 1 April 2011 - AC Motors Part 2
May 2011 - AC Motors Part 3 June 2011 - AC Motors Part 4
July 2011 - AC Motors Part 5 Aug 2011 - AC Motor Torque
Sept 2011 - Switched Reluctance Motors Oct 2011 - Modeling & Design Software
Nov 2011 - Suction Specific Speed Revisited Dec 2011 - Wastewater Drawdown Calculator
Jan 2012 - Off BEP Energy Calculator Feb 2012 - Centrifugal Pump Efficiency Part 1
Mar 2012 - Centrifugal Pump Efficiency Part 2 April 2012 - Centrifugal Pump Efficiency Part 3
May 2012 - Centrifugal Pump Efficiency Part 4 June 2012 - Centrifugal Pump Efficiency Part 5
July 2012 - Centrifugal Pump Efficiency Part 6 Aug 2012 - Bernoulli - Part 1
Sept 2012 - Bernoulli - Part 2 Oct 2012 - Velocity Head
Nov 2012 - Affinity Calculators Dec 2012 - Learning
Jan 2013 - Volts per Hertz & VFD HP Feb 2013 - Branch Line Pumping Options Part 1
Mar 2013 - Branch Line Pumping Options Part 2 April 2013 - Three False Forces & One Real Force
May 2013 - Motor HP & Torque Versus VFD Frequency June 2013 - Wye / Delta Part 1
July 2013 - Wye / Delta Part 2 Aug 2013 - Wye / Delta Part 3
Sept 2013 - Breadth of Efficiency Oct 2013 - Dezincification
Nov 2013 - Wastewater Pump S Values Dec 2013 - Parallel Analyzer
Jan 2014 - Hydraulic Rams Feb 2014 - The Cost of Pumping
Mar 2014 - AC Motor Efficiency April 2014 - Igor Karassik
May 2014 - Submersible WW Pump Testing Part 1 June 2014 - Submersible WW Pump Testing Part 2
July 2014 - Voltage Variation & Unbalance Part 1 Aug 2014 - Voltage Variation & Unbalance Part 2
Sept 2014 - Power Factor A Tale of Two Currents Part 1 Oct 2014 - Power Factor A Tale of Two Currents Part 2
Nov 2014 - Power Factor A Tale of Two Currents Part 3 Dec 2014 - Goodbye!!
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Other Publications - Joe Evans, Ph.D
The work I did prior to 1986 was quite different than what I do today. I attended grad school (69 - 73) during an interesting era. The advent of the minicomputer in the late 60's and early 70's allowed us to accomplish things that were impossible for those before us. All of a sudden, data generated by scientific instruments (especially the gas chromatograph - mass spectrometer (GC-MS)) that used to take months to analyze provided results within days. Back then the typical minicomputer was the size of a filing cabinet and had 2 - 4 K of memory. Data storage was on paper tape or maybe mag tape if you were lucky. It was still the time of the slide rule and analog recorders and just comparing the area under two plotted curves could take hours. Much of our work on instrument automation was sponsored by NASA and the Robert A Welch Foundation. We were also chosen as one of the few labs to analyze the soil samples gathered by the first NASA Lunar Lander project.
In 1973 I entered the army as captain and chief of the Air Chemistry Branch of the Army Environmental Hygiene Agency. This agency was the army's version of the EPA/NIH and its research was designed to protect our troops and reduce our impact on the environment. One of our major projects at the time was monitoring the detoxification and disposal of our WWII nerve gas stock pile at Rocky Mountain Arsenal (which, by the way, was stored for decades right at the end of the main runway of the old Denver airport). During my stay I continued my work on instrument automation and also the miniaturization of those instruments for use in the field.
After leaving the army in 1975 I joined Finnigan Corporation, a major GC-MS developer and manufacturer of the era. I was in charge of the East Coast applications lab in Washington DC and later moved into the position of product manager. By the mid 70's the minicomputer had advanced substantially and this technology gave us the ability analyze the data provided by a GC-MS in real time - - not days.
In 1977 I made the decision to move to Hawaii and, except for the University of Hawaii, there were no job opportunities that could make use of my past experience. Hawaii is a major union state and unfortunately this spilled over to the university and I doubted that I would fit in well in that environment. So, on a lark, I changed directions and took a position with IBM. Oddly enough, my minicomputer experience paid off and over the next five years I worked in industrial automation as well as distributed processing in the business community. One of our major accomplishments was the implementation of a on line directory assistance system at Hawaiian Telephone. It was a distributed processing system that consisted of three layers of minicomputers and fixed head disk drives that could perform searches as deep as nine levels of indent in seconds. The result was a directory assistance operator reduction of about two thirds which the union, of course, did not see this as a useful technological advance. Although it was nowhere near the speed of Google, it was lightning fast for its day.
In 1983, the Queen's Medical Center (Hawaii's largest healthcare organization) offered me the position of VP of Information Services. I learned early on that accepting this job was a mistake as I was unaware of the politics and in fighting that went on in these "non-profit" organizations. Still, in less than three years we were able to take them to the forefront of the information age. We were the first company in Hawaii to employ personal computers instead of dumb terminals and we had our own "intranet" email system in early '84. Unfortunately continuing confrontations with the CEO (a psychiatrist who was having an affair with the head of nursing who had a striking resembalance to "Miss Piggy") led to my demise in late '85.
In 1986 I accidentally fell into the pump industry. And, as most of you know, once you are in this industry it is hard to escape! Below are several papers that I published or took part in prior to that fall.
Isolation and Partial Characterization of Supernatant and Mitochondrial Shrimp Muscle Malate Dehydrogenases
This paper, published in Comparative Biochemistry & Physiology (Pergamon Press), was a result of the research performed for my masters thesis. It is co-authored by my advisor and two of my associates. The work was sponsored by the National Institutes of Health and the Robert A Welch Foundation.
Program ELAL: An Interactive Minicomputer Based Elemental Analysis of Low & Medium Resolution Mass Spectra
This paper, published in Analytical Chemistry (American Chemical Society), was a result of some of my doctorial research and follow on work done at the U.S. Army Environmental Hygene Agency. The program was the first to computerize the manual elemental analysis methods developed by Dr. Fred McLafferty at Cornell University.
Monitoring Organic Vapors
This paper, published in Environmental Science & Technology (American Chemical Society), was a result of my continuing work at the U.S. Army Environmental Hygene Agency. It discusses the ongoing micro-computerization and miniaturization of environmental monitoring instruments. It was co-authored by Jim Arnold of Varian Associates, a physicist and major contributor to technology advances in mass spectrometry and nuclear magnetic resonance (NMR) spectrometry (now known as magnetic resonance imaging (MRI) due to our ignorance and fear of that other "n" word). The mass spectrometer described in this paper was the predecessor of the one that was aboard the Mars Lander.
User Written Software Extends the Use of GC-MS Data Systems
Published in Finnigan Spectra (Finnigan Corporation), this article revisits the use of Program ELAL and introduces a new program known as FINL (fragment ion and neutral loss analysis). FINL automated another manual elemental analysis methodology that was developed by McLafferty at Cornell University.
INFO
In 1983 I left IBM and assumed the position of VP of Information Services at The Queen's Medical Center in Honolulu. One of the first things that we did was to initiate a news letter to keep the employees of our almost 150 departments up to date on what we were doing. This is the first issue.
The Queen's Medical Center - - A Royal Link to the Past and the Future
In late '83 we entered into an agreement with Management Science America (MSA) to install their GL, AP, and Payroll/Personnel systems and their "Peachpak" interactive PC products. This article highlights our accomplishments over a period of just one year.
OA Reigns Supreme at Queen's Medical Center
In 1985, "Today's Office" (Hearst Business Publications) selected Queen's as one of the nation's leader's in office automation and asked me to write an article outlining what we had done to get there. This was my last non-pump article!
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Education Links
Intro To Pumps - Basic Pump Training & Weekly Pump Industry News
http://www.introtopumps.
FreeCalc.Com - Lots of Good Online Calculators
http://www.allaboutcircuits.com/vol_2/index.html
Pump School - A Rotary Pump Course
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