Pump Ed 101

The tutorials and topics presented here were developed over the past twelve 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.

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. 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?

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.

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.

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.

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".

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.

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.

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.

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)

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.

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.

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.

During the past twenty-five 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.

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.

Hertz VHS is similar to Hertz except that it is customized for use with Pentair Water's PPC drive. It plots both 30-60hz and 30-80hz performance curves and allows you to properly size a 4" submersible or above ground pump to a constant pressure application.

Directions for its use and an explanation of the examples included 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 for the 60hz data entered. It also plots the 80, 70, 60, 50, 40, and 30hz curves for high speed operation. Curves are plotted in both feet and PSI. You can also enter "pumping level" (static level + drawdown + elevation) and obtain plots that show performance at the application point rather than the pump discharge. An optional, constant pressure curve allows you to compare a pump's output to the sytem requirements.

The PPSA 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.

Convert is a Windows based, desktop, conversion utility that is one of the most comprehensive I have run across. It allows you to convert just about any unit of measure to dozens of others. It also allows you to set up your own custom conversions. It was eveloped by Josh Madison ( http://www.joshmadison.com/software/convert/ )

Download (156k WinZip file - unzips to a 548k exe file)

Return to Titles

VFD Pump Selection - Constant Pressure - Joe Evans, Ph.D

This tutorial goes into a fair amount of detail concerning the proper selection of booster pumps for VFD applications. It starts by comparing a PRV controlled booster with one under VFD control and then outlines five rules that should be followed during pump selection. It ends with examples of good and poor selections.

Download (215K Acrobat Document)

Return to Titles

VFD Pump Selection - Variable Flow / Variable Pressure - Circulation - Joe Evans, Ph.D

With this tutorial, we begin our discussion of applications that require varying flows but do not require constant pressure. Circulation is one of the more popular variable speed applications for many reasons. We begin with a discussion of closed loop applications, show a typical system curve, and then illustrate the pump curves used for single and variable speed operation. We then move on to open loop systems and provide similar information.

Download (183K Acrobat Document)

Return to Titles

VFD Pump Selection - Level Control - Joe Evans, Ph.D

In this tutorial, we take a close look at waste water pump down applications and show how they can often benefit from conversion to level control. We begin with a discussion of wet and dry pit installations and show an example of the pumps used in pump down applications. We then show the same pump operating in a level control environment. We end with some guidelines on pump selection.

Download (232K Acrobat Document)

Return to Titles

Pumping Level Calculator - Joe Evans, Ph.D

PLC is a very simple visual that allows easy calculation of the TDH required for submersible well pump applications. It breaks down TDH into six, individual components and illustrates their relationship both above and below ground.

Download (54K Acrobat Document)

Return to Titles

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. Steve can be reached at: encosw@earthlink.net

Download (1120K Acrobat Document)

Return to Titles

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)

Return to Titles

HPSA A Variable Frequency Sizing Tool - Level Control - Joe Evans, Ph.D

The Hydromatic Pump Selection Assistant is an excel program that allows you to evaluate a submersible or dry pit pump that will be used in a level control application. You can enter up to eight flow and head points from a 60 hz performance curve and then view its operating curves from 30 to 60 hz. If you enter a system curve and the "pump down" elevation you can also view the same pump operating in a pump down environment. Finally, if you enter the hydraulic efficiencies for each point, brake horsepower will be calculated automatically and displayed as "data labels" on each of the curves. Scroll down to the bottom of the spreadsheet for complete directions and notes on the example that is included.

Download (128K Excel Document)

Return to Titles

Cavitation - A Largely Misunderstood Phenomenon - Joe Evans, Ph.D

The goal of this tutorial is to help you gain a intuitive understanding of the cavitation process and its causes. I will leave its prevention to the many articles that already exist. Since boiling is the precursor to cavitation, we begin by taking a look at some of the properties of water and their role in the cavitation process. We then put NPSH into perspective and review some of the dynamics of centrifugal pump operation that also directly affect the process. We conclude with a discussion of the different types of centrifugal pump cavitation and the conditions that can cause them to occur.

Download (519K Acrobat Document)

Return to Titles

About the Author

Joe Evans is the Western Regional Manager for the Hydromatic Engineered Products division of Pentair Water and lives in beautiful Rhododendron Oregon,near the pass at Mt Hood. Since entering graduate school, a continuing interest has been one of computer control of mechanical and electronic systems. It began with the introduction of the minicomputer, in the late sixties, and continued with the advent of the PC and PLC in the eighties and nineties. He accidentally entered the pump industry in 1986, and has been trapped there since. He is passionate about the sharing of knowledge and its ability to replace memorization with understanding. Click below if you would like to view a resume of his academic and professional experience. For a little history, click on the "Publications From a Previous Life" link which can be found in the VAST section of my home page.

Download (Resume Acrobat Document)

Return to Titles

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.

Download (1 MB Acrobat Document)

Return to Titles

Web Site Development & Hosting

Pueo Advanced Media offers web site development & hosting and is the brain child of my son Jamie. Whether you need a "plain Jane" site like mine (well maybe not quite as plain as mine) or something much more sophisticated, he can provide it at a reasonable cost. Hosting is also inexpensive and starts at under $ 7.00 per month. Click below and take a look at some of his work. And, I am sure that he would want to make it perfectly clear that he did not do mine (but he does host it). I have to take full responsibility for its "no frills" look.

Pueo Advanced Media

Return to Titles

Why Newton Invented Calclus - Joe Evans, Ph.D

Math -- one of those four letter words that can bring on anxiety attacks. It is sad that such a useful science has gotten such a bad rap. But, quite frankly, you can blame it on the teachers for it is they who have missed this great opportunity. This short tutorial provides a brief history of calculus and gives some every day examples of why is still needed today -- even in the pump industry. It also takes a few jabs at our educational system for not doing a better job of presenting math in high school and college. But, most importantly, it promotes less complex math (algebra) as a component that can help us better understand basic hydraulics and mechanics.

Download (122K Acrobat Document)

Return to Titles

Three Phase Motor Starting Techniques - Joe Evans, Ph.D

New comers to the pump industry are often unfamiliar with many of the three phase motor starting techniques that employed “pre-semiconductor” technology. Surprise - - most of them are still in use and will probably be here for some time to come. The primary purpose of alternative starting techniques is to reduce the system loading during starting. The typical AC induction motor has an inrush current, during starting, that is about five to seven times that of run current. Today, the VFD can provide a soft start and stop automatically just by ramping the input frequency. In the past it was not always that easy. This tutorial will review the most common methods of motor starting.

Download (282K Acrobat Document)

Return to Titles

Positive Displacement Pumps - Parts 1 & 2 - Joe Evans, Ph.D

There are many pump designs that fall into the positive displacement category but, for the most part, they can be nicely divided into two basic groups. The reciprocating group operates via pistons, plungers, or diaphragms while rotary pumps use gears, lobes, screws, vanes, and peristaltic action. Their common design thread is that energy is added to the pumped fluid only periodically where, in dynamic pumps, it is added continuously.

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)

Return to Titles

Sizing Pumps After Sunset - Joe Evans, Ph.D

I really had to think long and hard about putting this up on my web site. Hopefully you will never have to use it but, it can allow you to size a replacement end suction, centrifugal pump with a minimal amount of information. It uses something I call BEP sizing and includes several "family" curves that are made up of average BEP flows and heads from almost 400 individual pumps. If you decide to download this tutorial, use it carefully.

Download (79k Acrobat Document)

Return to Titles

Background Image - Mt. Hood

The birds eye view of Mt. Hood, that is the background to my title page, shows the winter version of the mountain the American Indians called Wy' East. At 11,235' it is the tallest peak in Oregon and is home to 11 glaciers and 5 ski areas. 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.

Return to Titles

Series / Parallel Pumping Calculator with Autoplot - Joe Evans, Ph.D

The resulting pressure and flows obtained when identical pumps are operated in series or parallel can be intuitively obvious. But, when those pumps are not identical, our analog brains often need to see a graphical presentation of those results. The Series / Parallel Calculator is an Excel program that allows you to view the combined performance curves of identical and similar pumps when running in series and parallel installations. It also allows you to enter a system curve so that you can evaluate their performance. After you download and start the program, scroll down for detailed instructions and a description of the example that is included.

Download (130k Excel File Revised 5/20/06)

Return to Titles

VFD Pump Selection - Frequency vs RPM ? - Joe Evans, Ph.D

I receive several emails each month asking why my VFD sizing programs (Hertz, Hertz VHF, HPSA, & PPSA) show the resulting curves in hz rather than RPM. This short paper explains my reasoning.

Download (55k Acrobat File)

Return to Titles

Centrifugal Pump Efficiency - What, How, Why, When ? - Joe Evans, Ph.D

In this tutorial, we will investigate several aspects of centrifugal pump efficiency. First I will define efficiency and give some examples. Next we will examine some of the design criteria that ultimately dictate the efficiency exhibited by a particular pump. We will also try to make that somewhat nebulas quantity, known as specific speed, more meaningful. I will also show its effect on the shape of a pump’s performance and power curves. Finally, we will discuss the importance of (or, sometimes, unimportance) of efficiency as it relates to a particular application or process. We will also illustrate the relationship of efficiency, head, and flow as they apply to both steep and flat performance curves and their roles in constant and variable speed applications. We will end with a brief look at the combined efficiency of a pump and its driver.

Download (461k Acrobat File)

Return to Titles

Waterhammer - Its All About Conserving Energy - Joe Evans, Ph.D

Most of us are familiar with the phenomenon known as waterhammer (water hammer) but few realize how destructive its force can be. Neither can we visualize some of the events that lead to its inception and those that occur afterwards. Did you know that waterhammer is a real life example of one of Physics' most fundamental laws? In this tutorial we will investigate both the cause and effect of waterhammer. We will also look at several methods of mitigating its damage and inception.

Download (233k Acrobat File)

Return to Titles

Educational Seminars & Training

The recipie for Pump Ed 101's educational seminars and training is a simple one. Combine the subject matter with many years of hands on experience, a dash of simple physics, a bit of history, and a generous portion of practical examples. Stir well and sprinkle with interaction. The result is a learning experience for everyone involved, regardless of their prior knowledge of the subject.

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, NGWA, RWA, and other pump oriented organizations. Drop me an email if you are interested in an on site seminar or have questions.

Click on the seminar catagories below to download the pdf that describes the seminars available for that catagory. Depending upon the subject, presentations will be a half or full day. Half day seminars can be mixed and matched for a full day of education.

Centrifugal Pump Training AC Power & Induction Motors Motor Control Centrifugal Pump Applications

Return to Titles

Centrifugal Pump Dynamics - Joe Evans, Ph.D

"Dynamics - the branch of mechanics that deals with the motion and equilibrium of systems under the action of forces related to motion." Well, no wonder you have never investigated this before - - it sounds pretty boring! But, believe or not, dynamics is actually quite interesting (and simple) and it is the key to understanding how centrifugal pumps work. This short tutorial will allow you to fully appreciate what goes on inside those pumps - - all the way from the inlet to the discharge. I have chosen the html format for this one so that I can take advantage of some imbedded animations and links to several other sites that will help us visualize what is going on. Make sure that Java and Flash are enabled. It is also available as a pdf document but you will not be able to take advantage of the animations. Enjoy!

Dynamics Html Version Dynamics Acrobat Version (98k pdf file)

Return to Titles

Hydromatic Stuff

The purpose of my web site is purely educational and I try to keep its contents neutral. That said, if you are interested in learning more about Hydromatic (my employer) and the products it offers, check out the links below. Hydromatic is a member of the Pentair family of companies.

Hydromatic Pumps H Series 4" Submersible Non-Clogs Novus Controls H2O Optimize Pentair Water

Return to Titles

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.

Return to Titles

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.

Download (75k Acrobat File)

Return to Titles

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.

Download (92k Acrobat File)

Return to Titles

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.

Download (80k excel file)

Return to Titles

Pumps & Systems Magazine Columns - Joe Evans, Ph.D

In September of 2006 I began contributing a monthly educational column to Pumps & Systems Magazine. I will make the unedited versions available here in pdf format as they are published. If you do not already subscribe to P & S you can do so online at http://www.pump-zone.com/

Sept 2006 - Centrifugal Farce & Affinity                                       Oct 2006 - Why Pump Curves Slope Down

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

Return to Titles

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 and the microprocessor 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