Q. We recently purchased several magnetically driven rotary pumps for our process and want to know if we need to be aware of any special operational considerations. A. The operation of magnetically...
Q. What information is available regarding bearing minimum loads for pumps? A. All rolling element bearings require a minimum applied load. This ensures that normal elasto-hydrodynamic operation...
Q. What are some factors to consider when conducting a life-cycle cost evaluation for a sealless rotary pump? A. There is a substantial first-cost premium for sealless rotary pumps. Depending on...
Q. What information is available regarding NPIPA and NPIPR for rotary pumps? A. Net positive inlet pressure available (NPIPA) is the algebraic sum of the inlet and barometric pressure minus the...
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...
Outside- Versus Inside-Mounted Seals, Pump Input Power & Rotodynamic Pump Motor Cooling
Q. What are the advantages of single, outside-mounted seals versus that of single, inside-mounted seals?A. Single seals have one set of sealing surfaces. The lubricant for the seal faces is usually...
Boiler Feed Pumps, Residual Mechanical Unbalance & Process Pump Piping System
Q. What considerations should be made when selecting the proper boiler feed pumps for a typical 400-megawatt, combined-cycle power plant?A. The operating range of the plant compared to the operating...
Boiler Circulating Pumps, Auxiliary Cooling Water Pumps & Mounting Base for a Sealless Rotodynamic Pump
Q. What information is available regarding boiler circulating pumps for combined-cycle power plant service?A. Boiler circulating pumps circulate water within the boiler to enhance boiler operation....
Boiler Feed Pumps, Chemical Metering Pumps and Hydrostatic Pressure Tests
Q. How are chemical metering pumps used in combined-cycle power plant applications?A. Numerous applications in a combined-cycle power plant require the delivery of precisely metered quantities of...
Outdoor Installations, Rotodynamic Vertical Pumps & Drooping Head
Q. What is a rotodynamic vertical pump? What pumps are classified in this way?A. Rotodynamic pumps are kinetic machines in which energy is continuously imparted to the pumped fluid by using a rotating...
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...
Effects of Solids on Slurry Pumps, Corrosion & the Alignment of Flexible Couplings
Pumps & Systems, April 2013Q. What are some effects of solids on a rotodynamic slurry pump?A. The performance of a rotodynamic pump moving slurries will differ from one moving water, which is the...
Submersible Pump NPSH3, Trench-Type Wet Wells & Starting Torque Requirements
Pumps & Systems, March 2013Q. How do I determine the NPSH3 for a rotodynamic submersible pump?A.  NPSH3 is the net positive suction head required, in meters (feet) that will cause the total...
Axial Thrust, NPIPR & Hydraulic-Coupled Tubular Diaphragm
Pumps & Systems, February 2013 Q. How does axial thrust compare among different impeller types for a rotodynamic vertical pump?A.  The net axial downthrust force is carried by the pump shaft....
Q. When selecting wetted pump parts, how much consideration should be given to the temperature of the pumped liquid? A. Handling liquids at temperatures below 32 F (0 C) or above 250 F (120 C)...
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...
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 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...
Hydraulic Institute Pump FAQs December 2011
Q.  How is the axial thrust for an end suction 
impeller calculated?A.  In a horizontal pump, the axial thrust is a net force acting through the rotor on the thrust bearing, including...
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 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...
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 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...
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 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...
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)....
Hydraulic Pump FAQs April 2011
Q.  When monitoring power consumption by a pump, what measurement methods are normally used and for what purpose?A.  Monitoring the power consumed by a pump can give advanced indication of...