ARTICLES AND OTHER INFO

THE INFLUENCE OF SPECIFIC GRAVITY ON TOTAL HEAD

In response to some questions raised by centrifugal pump Forum members on the use of pump performance curves with fluids other than water, I have written this short article that explains why specific gravity does not affect total head and the influence of viscosity.

UNUSUAL ASPECTS OF PUMP SYSTEMS

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There are many aspects of pump systems that have intrigued me over the years. Three such aspects are covered in this article.

The first is the attitude of the pump suppliers. Many purchasers require assurance that the pump they are about to buy will satisfy their requirements. This assurance is hard to come by.

A second aspect that has long fascinated me is the bizarre behavior of fluids. For example, the ability of a fluid to move upwards ( siphon) without a pump or any external source of energy is remarkable. Another interesting aspect is the large variation in pressure that can be seen throughout certain systems.

The third aspect is the effect of fluid properties (density, viscosity and vapor pressure) on the pump’s performance. The effect of these properties on the proper operation of the pump is considerable. This article has 26 pages and is a 1.4 Meg FREE download.

CENTRIFUGAL PUMP TROUBLE-SHOOTING CHART

The origin of this chart is unknown, however it is possible that it may have come from the Worthington pump company which no longer exists. It's a good chart with lots of information that fits on 1-page and I thank whomever contributed to it. Download or view in pdf format.

A COMPLETE EXAMPLE ON HOW TO CALCULATE PUMP TOTAL HEAD, N.P.S.H. AVAILABLE AND PRESSURE AT THE INLET OF A CONTROL VALVE

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This is a complete example using a real system which will take the reader through all the steps required to calculate the total head of a pump, the N.P.S.H. available and as a bonus the pressure at the inlet of a control valve. I have recently added calculations for the specific spped, the suction specific speed and the temperature rise. You will be able to compare the efficiency of the pump selected with the efficiency predicted based on the specific speed. All the charts, data and formulas required are included.

There are two files in the download, one is the exercise completely filled out with all the results, the other is the same exercise but with all the results left blank for you to fill in if you want to do the exercise on your own, good luck. The article contains 2 pdf files compressed into 1 ZIP file and is a 6.5 Meg download. Both documents are 36 pages long.

HOW TO CALCULATE PRESSURE ANYWHERE WITHIN A PUMP SYSTEM

Download an article on how to calculate the pressure anywhere within a system

Calculating the total head of the pump is not the only task of the pump system designer. Often we need to know the pressure at a specific point in the system. Suppose we have a system that transports a hot liquid, we know that hot liquids vaporize very easily under conditions of low pressure. There is a high point in our system where we know the pressure will be low but exactly how low? The techniques in this article will show you how to do this calculation for any point in the system.

This is an 8-page article and a 400 Kbytes download.

HOW TO DO PUMP PERFORMANCE MEASUREMENTS

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This article examines how to take flow and pressure measurement and then how to calculate the total head of a pump. How to do motor power measurements and where to get efficiency, power factor and other data for typical induction motors. What is power factor anyway? Find out here. This is an 18-page article and a 1Meg download.

PIPE ROUGHNESS VALUES

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Values for pipe roughness can sometimes be hard to find. I have been meaning to put a list together of values for absolute pipe roughness, so here it is. These values will typically be used with the Colebrook equation to calculate the friction parameter and then the pressure head loss due to friction in pipes. This is a 1 page article and a FREE 55 kByte download.

EFFICIENCY AND POWER FACTOR VALUES FOR ELECTRIC INDUCTION MOTORS

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This article is the compilation of efficiency and power factor data that was obtained from 6 major motor manufacturers in year 2000 by Fluide Design for industrial electric induction motors ranging from 10 to 200 hp. There is a short primer on power factor and also a comparison between manufacturers for the costs associated with low efficiency. This is a 19- page article and a 200 Kbytes download.

CENTRIFUGAL PUMP SPECIFIC SPEED AND THE AFFINITY LAWS

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Ever see this cool image and wonder what its about? I know I have. This is a chart showing the specific speed of a pump and what type of pump corresponds to which specific speed range. This short article will give you the gist of it. Check it out! Find out how your pump compares in terms of efficiency with the average in the industry. Oh yeah and I also added a few words on the mysterious suction specific speed number. Yahoo!!! I couldn't leave it alone so I added information on the AFFINITY LAWS, how they were developed, how to use them and what the limitations are, YOU NEED TO KNOW THIS!. This is an 10-page article and 4.6 Megabytes download.

SPECIALTY PUMPS

This page lists a number of specialty pumps that are unusual and helpful in particular situations.

WHAT IS CAVITATION, AND WHAT CAN YOU DO ABOUT IT?

This is a short 4-page article and 1Meg download on cavitation, a nice simple explanation with no formulas, I swear. You can download the article from here in pdf format. If you have never heard the sound of cavitation here's a recording of it in WAV format, courtesy of my friend Normand Chabot, water hammer specialist here in Montreal.

MORE ON WHAT IS CAVITATION

This next article follows the above and deals with the relationship between N.P.S.H. required and cavitation. You can download and view this article in pdf format. There is a couple of formulas, so just breeze through those parts if you are not so inclined. You will find how you can affect N.P.S.H. and how you can measure it among many other facts. This is an 11-page article and 750 Kbyte download.

WHAT TYPE OF CENTRIFUGAL PUMP DO YOU HAVE?

Finding the right centrifugal pump for the job or identifying the pump that you have amidst the large quantity of available pump types can be a challenge. This flow chart based on the nomenclature proposed by the Hydraulic Institute www.pumps.org will help you identify your pump.

THE INNER WORKINGS OF A SIPHON

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The objective of this article is to explain how a siphon works. The difference between low pressure, atmospheric pressure and pressure is explained. The different pressure measurement units are discussed as well as the variation in atmospheric pressure depending on location or elevation with respect to sea level. The readers will be able to perform many experiments helping explain these concepts with easily available materials. Seems like allot to explain the behavior of a simple siphon, that is because all is not as it appears. This is a 22-page article and a 1.3 Meg download.

ARTICLE ON A VISCOUS DRAG PUMP

CALCULATE THE MAXIMUM PRESSURE ALOWABLE AS PER ASME PROCESS PIPING CODE B31.3

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A method for calculating the pressure level corresponding to the allowable stress in a pipe as recommended by the ASME Piping code. This is an 8-page article and a 800 Kbyte download.

PROGRESSIVE CAVITY PUMP PROTECTION

VALUES FOR EFFICIENCY AND POWER FACTOR FOR INDUCTION MOTORS FOR DIFFERENT MANUFACTURERS