Sims Pump Co. Reduces Energy Consumption by 20 Percent with Structural Graphite Composites
Pumps and Systems Success Story of the Year 2010 FinalistThe impeller of the Central Saltwater Cooling Pump on the USNS Lewis and Clark was demonstrating premature wear and efficiency from corrosive...
Slow Down and Think Causally to Solve Pump Problems
 Is it becoming harder to find time to think instead of react? The blistering pace of information bombarding us and being requested drives us farther into the abyss of reactivity. It is...
Public works officials who manage the nation's wastewater treatment plants (WWTPs) would universally agree that a "weak" link in any plant's process chain can cause big-and often expensive-problems....
Pump Challenge #1 - an impeller cut problem - is an application of the Affinity Laws to reduce the motor amps and solve a motor tripping problem. The full details of the challenge can be seen by...
Specialty Materials Help Improve Pump Reliability and Save Energy
Efficiency degradation in pumps can be related to three areas. Worn clearances between the wear rings of the impeller and the casing can increase leakage and drop the volumetric efficiency of the...
For many of us, water is the only liquid that flows through our centrifugal pumps. Consequently, specific gravity (SG) and viscosity are not factors when sizing them. But, if you work with other...
Last month we learned that the power required by a centrifugal pump is directly proportional to the specific gravity (SG) of the pumped liquid. We also learned that as long as the liquid has a...
Stable and Unstable Pump Curves
A “stable” curve is important for pump operation, especially for pumps in parallel operation. The higher the energy level and the more critical an installation, the more the pump curve could...
By lifting wastewater to a higher elevation, pump stations are installed either in the gravity system or at the headworks of the wastewater treatment plant. Areas not suitable for gravity systems may...
Success Story of the Year 2009
The International Paper plant in Courtland, Ala., had experienced problems with a white water pump on a paper machine since the plant installed the pump in the late 1970s. The problem pump experienced...
Fighting Falling Lake Levels with an On-Shore Centrifugal Pump Commerce, Texas, relies on nearby Lake Tawakoni for supplying water, but falling lake levels were creating problems for its vertical...
Suction Calculators
Last month I reviewed an Excel-based Radial Thrust Calculator and showed how it can predict the magnitude of unbalanced radial thrust when a centrifugal pump is operated to the left of BEP. This month...
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...
Suction Specific Speed (Part Three): Using Suction Specific Speed to Establish Adequate NPSHA, net positive suction head, NPSH
Tenth in a SeriesA number of technical papers (1, 4, 7, 8) have shown that the maximum damage rate to centrifugal pumps, at least in water services, typically occurs when the NPSHA is in the range of...
Suction Specific Speed (Part Two)
Graph of Minimum Continuous FlowsIn 1982, Richard Dubner of Chevron developed a graph for use in establishing minimum continuous flow rates for centrifugal pumps (see Figure 1). It allows a lower flow...
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...
Testing Centrifugal Pumps in the Field
The performance curves generated by many pump manufacturers are based on results obtained in their test facilities under tightly controlled conditions. The testing techniques used in the field can...
The Impact of the Area Ratio
In March 1980, I attended the ASME symposium on Predicting the Performance of Centrifugal Pumps and Compressors in New Orleans. I was about three rows from the podium, sitting next to a fellow who...
Recently I was involved in a discussion with some folks from Chevron about the effects of viscosity on centrifugal pump performance. Here are some excerpts from our discussion: "The Hydraulic...
Definition of NPSHThe margin of pressure over vapor pressure, at the pump suction nozzle, is Net Positive Suction Head (NPSH). NPSH is the difference between suction pressure (stagnation) and vapor...
Use Simple Pump Troubleshooting Methods Before Rushing to Fancy Analysis
When the motor amps are kicking a unit offline, the first question is whether the motor or the pump is the problem. Before any sophisticated troubleshooting methods are applied, most experienced...
This study establishes the relevant characteristics of sludge and how they affect the performance of pumps with a swept-back leading edge impeller and relief groove in the volute and head losses in...
Transporting large pre-fabricated modules to a remote, hostile and storm-ravaged environment is difficult and not without risk. For this reason, centrifugal pumps were chosen to play a key role in...
3-D laser scanning is a relatively new technology that yields a three dimensional virtual record of a real object. The concept is simple and similar to police radar, but requires the power of modern...
In the late 90s, I used Excel to develop a simple graphical system that showed the variable speed performance of a pump based upon its published 60-hz H/Q curve. I have modified it to model several...
Vibration Analysis Simplified
Last year in “Trending Revelations in Vibration Analysis,” (Pumps & Systems, June 2009), I discussed the importance of statistic trending in vibrations analysis. Usually, as most would expect,...
Vibration Analysis to Improve Pump Reliability and Save Energy
 Vibration analysis trending can be a helpful tool in predicting brewing problems, before they develop into a big issue. The Kemira/FinnChem plant (Kemira) in Augusta, Ga., started a vibration...
When we start the pump selection process for a particular application, one of our major concerns is efficiency. If several different models of similar quality meet our conditions, we will usually...
Proper installation and adjustment can make the difference between the success and failure of a packed pump. By keeping in mind the fine points of a few key principles, the chances of success are...
Consider a typical sewage collection system. At the initial point of discharge, water first flows (by gravity) into a network of (sloped down) drain pipes, which gradually intercept a larger main...