Q.We have recently installed several double suction between bearing pumps and would like to verify that their vibration levels are within acceptable limits. How should this be done, and what is an...
Q. What does the expression discharge recirculation signify in rotodynamic (centrifugal) pumps? When does it occur, and is it harmful to the pump?   A. Discharge recirculation is circulatory...
Q. What is the maximum pumped liquid temperature that an end suction centrifugal pump can handle, and what must be done to a pump for it to operate successfully at that temperature?A. Limits are...
Hydraulic Institute Pump FAQs August 2011
Q. Some slurry applications include froth in the liquid, which affects pump performance. What must be done when selecting centrifugal pumps for such applications?A. Froth is an aerated liquid medium...
Q.  When a centrifugal pump impeller is reduced in diameter to reduce total head and rate of flow, the affinity rules predict that the new rate of flow is equal to the original rate of flow times...
Q. We are expanding some of our buildings and need to replace the existing fire pumps. What are the technical requirements for such pumps?A. Pumps currently used for fire protection in buildings are...
Hydraulic Institute Pump FAQs January 2007
Q. I have been told that centrifugal pump impellers may still cavitate when operating with NPSH Available greater than NPSH Required. Is this true? If so, why do pump suppliers show NPSHR values when...
Q.  Most centrifugal pumps have a horsepower characteristic curve which rises as rate of flow increases to some level and then levels off or turns downward. However, other pumps have more level...
Hydraulic Institute Pump FAQs January 2010
Q. I understand the significance for properly configured suction piping, but what are the piping requirements on the discharge side of a rotodynamic (centrifugal) pump?A. The maximum velocity at any...
Q. When installing a horizontal pump, is it better to grout the pump baseplate or let it float free?   Different sources provide opposing views on this subject.A. Whether to grout...
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...
Hydraulic Institute Pump FAQs November 2011
Q.  What is a balanced mechanical seal, and when is it usually used? A. Balancing a mechanical seal involves reducing the effective forces on the seal faces. A general rule is to use a...
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...
Hydraulic Institute Pump FAQs October 2010
Bearings used in high-temperature applications, suction recirculation in pumps and Newtonian and non-Newtonian fluids Q. We are frequently replacing the ball bearings in an end suction pump that is...
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 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...
Hydraulic Institute Pump FAQs September 2010
Centrifugal pumps: do they handle slurries, and what is their maximum allowable working pressure?Q. How do rotodynamic (centrifugal) pumps perform when handling slurries?A. The performance of a...
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)....
Editor's Note: This is part two of a two part series about the 'commandments' of increasing pump reliability and life.Last month, we discussed Commandment 11, Thou shalt always operate...
 Pumps & Systems, March 2007What's hot and what's not with pumps in the water/wastewater industry.Born in the 3rd century BC, pumps are one of the most important mechanical devices in all...
The number of compressor and pump package orders in the energy sector has increased greatly over previous years' level due to increased activity in the oil & gas production, transmission and...
The "Ten States Standards" and other municipal and state codes require submersible wastewater pumps to pass a minimum 3-in spherical solid. This is not a difficult task for many 4-in and larger...
Centrifugal pumps need to be kept in tip-top condition to handle harsh liquid-terminal operations.Without question, liquid storage terminals play an integral role in the ongoing success and relevance...
In many cases, users rent pumps to help them meet specific project requirements. The user does not always want to purchase a pump because he may not have the knowledge, manpower or time to service and...
Maximizing Your Rental Experience
In many cases, users rent pumps to help them meet specific project requirements. The user does not always want to purchase a pump because he may not have the knowledge, manpower or time to service and...
Net Positive Suction Head: NPSHR and NPSHA
Addressing Net Positive Suction Head (NPSH) and its relationship to cavitation
Newtonian and Non-Newtonian Fluids
How viscosity affects centrifugal pumpsThe Hydraulic Institute published a standard to account for the effects of viscosity of centrifugal pump performance. Effects of Liquid Viscosity on Rotodynamic...
Not All ANSI Pumps Are Created Equal
OEM pumps and parts outperform replicated products, and can save thousands per year in operating costs. Industrial process managers who purchase and maintain pumps are familiar with a marketing...
NPSH: A Characteristic of All Pumps
Note from Terry Henshaw:This is the first in a year‑long series of articles called Understanding NPSH. These articles were originally prepared as class notes for the all‑day seminar on NPSH...
Vast tonnages of oil sands are now being transported as slurries in centrifugal slurry pumps as the first stage of the bitumen extraction process. Similarly sized pumps are also used to transport the...