Q. What is the estimated time between repairs for common wastewater pumps? A. The optimal performance or life of pumping equipment will be achieved when the equipment is correctly designed, sized...
Q. What is NPSH3, and what are the methods for determining the NPSH3 of a rotodynamic submersible pump? A. NPSH3 is the net positive suction head available to a pump under test at a constant rate...
Q. What are the advantages and limitations of a sealless pump design? A. A sealless pump is used when there is a need to contain toxic, dangerous and/or valuable fluids. Application may be...
Q. What are some effects of a gas and liquid mixture being carried through a rotodynamic pump? A. The most dramatic effect of gas or vapor on rotodynamic pump performance is the blocking of the...
Q. What specifications are required for series and parallel pump operations? A. Pumps intended to operate in series must be close in size because of the rate of flow. Pumps operating in series...
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...
Q. When dealing with wastewater treatment pumps, what concerns pertaining to site conditions are relevant? A. The type of pump that can be used depends on the location of installation. These...
Q. How can we determine the proper size for the intake sump to accommodate several vertical turbine pumps taking input from a river? A. The basic design requirements include adequate depth of flow...
Q. What dynamic analysis considerations are recommended for the petroleum market? A. End users should evaluate their need for dynamic analysis by considering the level of proven field experience...
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,...
HI Pump FAQs is produced by the Hydraulic Institute as a service to pump users, contractors, distributors, reps and OEMs.
Q. How does a liquid’s viscosity affect the performance of rotary sealless pumps? A. The viscosity of a pumped fluid affects the input power and magnetic coupling torque required in a rotary...
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....
Q. What is a string test, and when should one be specified? A. Generating a pump curve requires the measurement of head, capacity and power. From this information, the efficiency of the pump can be...
Q. What are some typical indicators of an inefficient pumping system? A. Many pumping system components are not dynamic. These components allow fluid or heat transfer, but aside from thermal...
Q. What is a regenerative turbine pump? A. Regenerative turbine pumps are characterized by a low flow rate and high head. They use peripheral or side channel vanes or buckets that are manufactured...
Q. What are the effects of viscosity on rotary pump and system performance? A. The viscosity of a pumped fluid typically affects pump ratings in the following ways: The net positive inlet...
Q. What are some differences between specific speed and suction specific speed for a rotodynamic pump? A. The Hydraulic Institute defines specific speed as an index of pump performance (developed...
Q.What are “nonclog pumps,” and in what applications are they used? Figure 1. Dry pit pump – overhung flexibly coupled vertical end suction A. “Nonclog pumps” are rotodynamic...
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 ways to monitor the power used by a rotary pump? A. Instrumentation and systems can be used, such as: Torque meter—The most direct way to monitor power is a torque meter with...
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. 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)...
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....