Q. What methods are recommended for measuring a controlled-volume metering pump's flow rate, and what should be taken into account to ensure an accurate measurement? A. The following methods can be...
Understanding this complex topic can help end users avoid common pitfalls.
Q. What are the best materials to use in pump construction to minimize part corrosion? A. Factors to consider in the selection of materials for wetted pump components include user's experience,...
Lev Nelik answers a reader's question on thermodynamic sub-processes that are highly time dependent
Q. Can rotary type pumps be used to pump slurries? If so, should users be aware of any special precautions? A. Rotary pumps may be used to transfer slurries when the application dictates....
Correct equipment selection and application saved an aluminum producer $36,000.
Reconstruction and infrastructure upgrades require pumps made from durable materials.
This is the first article in a four-part series. Four part 2, click here. Second only to electric motors, centrifugal pumps are usually the simplest machines in a typical process plant. Pumps...
One of the supposed advantages of centrifugal pumps when compared to positive displacement pumps is their ability to operate across a wide flow range. Because a centrifugal pump operates at the...
Pressure gauges are inexpensive components that can predict the causes of poor reliability in centrifugal pumps and prevent costly repairs and downtime.
Many options are available to meet industry and application requirements.
Q. What is NPSH3, and how does it relate to the NPSHR for a rotodynamic pump? A. The Hydraulic Institute defines the required net positive suction head (NPSHR) of a pump as the net positive suction...
Q. What are some adverse effects that can occur from mechanical processes during pumping operations? A. Numerous mechanical processes during pumping operations are not typically duplicated in...
Magnetic Couplings, NPSH Margin &  Reverse Runaway Speed
Q. What are the effects of increasing temperature on the magnetic couplings in a rotary sealless pump?A. Eddy currents in the containment shell are one source of heat in a sealless pump. Heat is also...
The Hydraulic Institute’s New Test Standard
ANSI/HI 14.6 gives the pump community a globally accepted test standard 
for rotodynamic pumps.
After reading two of my articles on power pump valves, valve springs and net positive suction head required (NPSHR), Brazilian engineer Ricardo Martuscelli emailed me to suggest that I create graphs...
I have a pump that was used to pump natural gas condensate with a specific gravity of 0.7599 and now is used to pump water with a specific gravity of 1.005. I would be very happy if you helped me...
Centrifugal Pump Axial Thrust
The late Charlie Jackson, vibration expert at Monsanto, once told me that he was unaware of any centrifugal pump manufacturer that knew how to calculate the hydraulic axial thrust produced within the...
The concept of “suction energy” was developed to enhance the evaluation of the NPSH characteristics of centrifugal pumps, but I fear that it misses the mark. Suction energy is defined as the...
HI Pump FAQS January 2012
Answers to the industry's pressing technical and management questionsQ.  When purchasing new rotodynamic pumps, what type of acceptance testing is recommended?A.  Purchasers of rotodynamic...
1)  Only select pumps with suction specific speeds less than 11,000-less than 9,000 is even better.2)  Select your pump so it never operates below 70 percent to 80 percent of its best...
 Solution to Pump Challenge #2: Moving a Pump from the Bottom of a Dry Pit
In the August 2009 issue, we considered the following challenge: From the available data tables, the vapor pressure of 150 deg F water is about 4 psia, or (x 2.31) = 9 psia.Initially, when the...
Pumps & Systems, July and August 2007  A review of traditional metering pump designs, along with a look at some of the new technologies that are being introduced. The metering pump is a...
Acceleration Head
The Thirteenth in a SeriesIf a centrifugal pump is started with the discharge valve open too far and with a low discharge pressure, the liquid in the suction line may accelerate at a rate that causes...
As energy costs rise and energy efficiency becomes more important in operating pumping systems, equipment suppliers, system designers and operators will maximize the efficiency of system components to...
Analyzing the Impeller Eye
This is a follow-up to my column on predicting centrifugal pump performance (Pump & Systems, May 2011), and offers equations that will enable the engineer to perform a partial analysis of the...
April-Wise Pump Quiz: NPSH and Developed Head
In this installment of “Pumping Prescriptions,” I have a quiz for our readers. A typical pump system is shown in Figure 1. A centrifugal pump delivers 200 gallons per minute of water from an open...
An OEM and an end user had installed a number of large, double-suction pumps for a water pumping station project (Figure 1). Soon after, they began to suspect that the pumps were a significant...