Hydraulic Institute Pump FAQs March 2011
Q. I am aware that there are requirements for the inlet piping of rotodynamic pumps. What are the requirements for the discharge piping of a pump?A. The maximum velocity at any point in the outlet...
Hydraulic Institute Pump FAQs September 2011
Q. What are bearing isolators and how are they used?A. Bearing isolators are composed of both a stationary and a rotating component that act in concert to retain lubricant and exclude contaminants...
HI Pump FAQS
Q. How carefully must pump impellers be balanced to avoid unacceptable vibration levels when the pump is running?A. Pump impellers are typically balanced in accordance with ISO 1940 balance quality...
Hydraulic Institute Pump FAQs June 2011
Q. When purchasing rotodynamic (centrifugal or vertical) pumps, how can we estimate if the efficiency of the proposed design is the best to be expected for our application?A. The Hydraulic Institute...
What is a Safe NPSH Margin for a Centrifugal Pump? Can You Provide Too Much NPSH?
Editor's Note: This is the fifth article in the year-long series, Understanding NPSH. To read the previous article, click here. To read the next article, click here.What is a Safe NPSH Margin for a...
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...
Pumps & Systems, July 2008Plastic is one of the most widely used materials in the manufacturing of everyday products, including food containers, toys, computers, medical equipment, building...
Suction Specific Speed (Part One)
The Eighth in a SeriesNormalizing NPSHOur attempts to normalize or classify water turbine hydraulic performance culminated in 1915 with the development of the specific speed concept, which was later...
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...
Pump Curve Accuracy
Digitization methods are critical when using pump selection software.First of Two PartsMore than 150 pump manufacturers present their pump performance data electronically. These digital pump catalogs...
Suction Specific Speed and Wastewater Pumps
In the February 2010 issue of Pumps & Systems, I wrote an article on my Excel-based Suction Specific Speed and Suction Energy calculators and how they can be used to predict the onset of suction...
Pumps & Systems, October 2008Q.What is a free standing baseplate and when should it be used? Are there any special design requirements?A.A free standing baseplate is designed to properly support a...
Hydraulic Institute Pump FAQs March 2009
Q. How can we tell if a pumping system is designed and operated properly? Some problems such as leaking seals are obvious, but should we watch for any other symptoms?A. A few symptoms in pumping...
Pumps & Systems, March 2008It is common practice for the designer of a new centrifugal pump to model the new pump from an existing pump. Each dimension of the existing pump (except the shaft...
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...
Hydraulic Institute Pumps FAQs June 2010
Balancing Pump Impellers; High Efficiency Pumps; Boiler Feed Booster PumpsA. Pump impellers are typically balanced in accordance with ISO 1940 balance quality grade G6.3 or better (see Figure B.2)....
How Does Pump Suction Limit the Flow?
One of the advantages of centrifugal pumps over positive displacement pumps is an ability to operate with a wide flow range. Since a centrifugal pump operates at the intersection of a pump curve and a...
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...
Suction-Side System Design; If You Do Not Have Enough NPSHA; Resistance of Materials to Cavitation Damage
Final Article in a 14-Part SeriesSuction-Side System DesignCentrifugal PumpsFigure 1 shows most of the features discussed below.  Straight Run Into Suction For satisfactory operation, a...
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...
Hydraulic Institute Pump FAQs September 2007
Q. What are the most probable causes of insufficient discharge flow or pressure in centrifugal pumps?A. Before looking at the pump, check the measurement of total head and rate of flow. The proper...
Hydraulic Institute Pump FAQs 2008
Q. I have heard that the rate of flow through centrifugal pumps can be regulated by submergence control instead of by throttling the pump discharge. How does this work, and does it damage the pump?A....
Hydraulic Institute Pump FAQs July 2011
Q. I see that many pumps for pumping slurries are made of either hard metals or elastomers. Why is this and which is better?A. A large variety of metals and elastomers are used for slurry pumps...
Hydraulic Institute Pump FAQs September 2008
Q. When operating centrifugal pumps on corrosive or erosive applications, how can the user determine when the casing wall is worn too thin for safe operation? What is the minimum safe operating wall...
 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...
Oil Sands Pump Performance Testing and Limitations
Many millions are spent in the oil sands industry providing new plants for the production of oil from tar sands. Oil sands pumps are a key component in these expansions.The cost of non-conformance can...
Due to high specific gravity, viscosity and particle size of mining materials, centrifugal pumps are continuously challenged in mining applications. New pump technology was created to efficiently move...
There are two largely accepted facts about mining: 1) A mine's landscape is dynamic, and 2) Within that landscape, water is a mine's worst enemy. Navigating a mine's landscape with pumps designed to...
Q. Is it true that centrifugal pumps should be built with ball bearings that have greater than normal internal clearance?A. It depends on the pump type and the conditions of service for the...
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...