As the pressure a centrifugal pump has to overcome increases, the discharge flow decreases until, at a certain head, the output drops to zero. Some type of pumping equipment must be used to generate the pressure for. Pump sizing and selection made easy chemical engineering. Positive displacement pumps are those in which energy is imparted to the liquid in a fixed displacement volume, such as a casing or a cylinder, by the rotary motion of gears. A number of different sizes are available but the most common model offerings are in the 2 to 4inch range with flows from 142 to 500 gallons per minute gpm and heads in the range of 90 to 115 feet. Jet pump is used when the suction lift of the centrifugal pump exceeds the. There is no math, just simple explanations of how pump systems work and how to select a centrifugal pump. Most submersible pumps with 5hp or less are 230vsingle phase.
The difference lies on one hand in the principle of transporting the liquid and on the other hand in the pumping characteristic. Basics concepts of operation, maintenance, and troubleshooting, part i by. Understanding centrifugal pump curves when selecting a centrifugal pump, one should match the performance of the pump to that needed by the system. Pump purchasers enter their fluid properties and system requirements to obtain a listing of suitable pumps. Positive displacement pumps allow liquid to flow into an open cavity trap the liquid in the pump transport liquid from the suction to discharge port mechanically force liquid out of the pump. The operating characteristic of a pump at a speed of 1430 revmin and a rotor diameter of 125 mm is as follows. A water system needs to move the water produced from the source to its customers. One of the subclassifications of the kinetic pump branch is the centrifugal type. Examples of total head calculations sizing a pump for a home owner application. Rocky mountain ashrae chapter mcnevin company aurora, co. Standard centrifugal pumps standard centrifugal pumps provide an economical choice for general purpose dewatering. Centrifugal pump curves characteristics continued bhp brake horsepower and capacity for the centrifugal pump to deliver the capacity we want, we must supply the pump with a certain hp. Pro services includes, pumpsmart variable speed drive systems, and ialert2 equipment health sensors. The design of a centrifugal pump makes them useful for pumping sewage and slurries.
Centrifugal pump fundamentals pumps are broadly classified as kinetic or positive displacement. To achieve optimum centrifugal pump performance efficiency for liquid flow rates within the range of 4. Centrifugal pumps enjoy widespread application partly due to their ability to operate over a wide range of flow rates and pump heads. The following conditions are used for purposes of discussion only. Once we know the gpm and pump head, we can start the centrifugal pump selection. They are also used in fire protection systems and for heating and cooling applications.
All centrifugal pumps use an impeller and volute to create the partial vacuum and discharge pressure necessary to move water through the casing. A selection chart shows the typical operating region for the various pump sizes for a given manufacturers pump type at a given rotational speed. He runs the mcnally institute, which conducts courses on pumps and seals. Typical selection criteria for centrifugal pumps are their design data flow rate or capac ity q, discharge head h, speed of rotation n and npsh, the. In metric units water power is expressed in kilowatts, pump capacity in liters per minute, head in meters. Centrifugal pump selection michael smith engineers. The results of the pump selection analysis are given in table 2. Centrifugal pump problems 5 overview of pump problems typically found on centrifugal pumps. The selection chart is useful in developing a shortlist of pumps for consideration that meets the process requirements.
Pump division pump product catalog experience in motion. As one experienced with pipe selection might predict, one would choose the centrifugal pump with a rotor diameter of 7 cm and a speed of 45 rpm. Centrifugal pump handbook written by sulzer pumps is very useful for mechanical engineering mech students and also who are all having an interest to develop their knowledge in the field of design, automobile, production, thermal engineering as well as all the works related to mechanical field. The pumped liquid must be clean, free of suspended solids or abrasive substances and chemically neutral. Pump sizing, or centrifugal pump selection, or sim ply centrifugal pump hydraulics analysis. Centrifugal pumpparts, working principle, application. Example design problems two design problems are provided that students can use to explore the pump selection design process. Software tools that allow you to evaluate and compare operating costs are available from private vendors. Centrifugal dynamic pumps are used in a range of industrial applications to transfer liquids from one point to another. Pdf centrifugal pump handbook by sulzer pumps free. This fourpart series of articles is intended to explain and develop the basic principles of pump operation and, except for sizing, allow the optimum selection of centrifugal pumps. Pdf download sulzer pumps by centrifugal pump handbook. Centrifugal pumps are used in buildings for pumping the general water supply, as a booster and for domestic water supplies.
Selection of centrifugal pumping equipment citeseerx. The first step on the way to the optimal pump is the selection between a centrifugal pump or a positive displacement pump. General components of centrifugal pumps a centrifugal pump has two main components. The efficiency of a centrifugal pump can be defined as the ratio of the output power water to the input power shaft. Reading and understanding centrifugal pump curves is key to proper pump selection, and to their reliable and efficient operation. Pump selection guide brown brothers engineers australia. And for other applications consult dab technical department. The choice of pump for a given application depends largely on how the pump headflow characteristics match the requirement of the system downstream of the pump. Pump specifications related to pump construction and performance selection of the appropriate type of metal e. Pdf exceltm in centrifugal pump selection researchgate. Water piping and pumps distribution systems 4 the change in water temperature as the water moves through the system the water gets colder after each successive terminal because of mixing creates the possible need of larger units at the end of the main, which will complicate the selection of the zone terminal units and add cost. Pump headflow curves are typically given for clear water. A spreadsheet program for the calculation of piping.
In choosing a pump, you firstly need to select a pump appropriate for your application. To use software intelligently, it is first necessary to understand the manual selection procedures. In almost all cases in minnesota, the source is at a lower elevation than the user so the water must be raised to a higher level. A typical composite curve includes the pump performance curves, horsepower curves and npsh required.
A coverage chart see figure 42 makes it possible to do a preliminary pump selection by looking at a. If theres no power on site, you need to spec a generator. It is the force performing on the liquid that makes to supply in the casing. Ft mtd foot mounted, flg mtd flange mounted automatic reversing gear pumps pgs. The increase in pressure head can be used to carry water from one site to another site. Goulds pumps and rheinhutte pumpen presents this centrifugal pump selection guide to assist users in making an easy initial selection of the best pump for a particular service. For those who want to do detail calculations, some examples have.
B foot mounted pump connected to motor with vbelt and pulleys mounted on baseplate mounting options. A nu mber of software p ackages are available as offtheshelf packages to carry out these tasks. Labour pump company 901 ravenwood drive, selma, alabama 36701 ph. Centrifugal pumps are the most common type of pumps found in doe facilities. Pump selection guidelines october 20 process industry practices page 4 of 58. This tech brief examines how pump curves can provide data about a pump s ability to produce flow against certain head, shows how to read a typical centrifugal pump curve, and provides. This tutorial is intended for anyone that has an interest in centrifugal pumps. Pump types typical selection criteria for centrifugal pumps are their design data flow rate or capac ity q, discharge head h, speed of rotation n and npsh, the properties of the fluid pumped, the application, the place of installation and the applicable regulations, specifications, laws and codes. Generally, the hp increases as we increase the capacity. Mukesh sahdev, associate content writer presented at the chemical engineers resource page.
A centrifugal pump is required to produce a flow of water at a rate of 0. The selection of a propeller pump is done based on the characteristic curves compared with the well discharge and head. You are told to purchase a pump for your manufacturing facility that will carry water to the top of a tower at your facility. They do this by converting mechanical energy from a rotating impeller into pressure energy head that moves liquid through the pump casing and through the system pipework, valves and process equipment. In some cases the pump selection is determined by some stringent requirements for a number of design or process parameters. The wet end consists of a rotating impeller within a casing with inlet and outlet connections. Water is spun outwardly through the impeller vanes and into a volute casing resulting in increased pressure. Reference centrifugal vertical npsh margin ansihi 9. Consist of a combination of a centrifugal pump and a jet mechanism or ejector. Volume rate of flow of liquid, expressed in cubic metershr m. Conversely, with no head to work against, a pump can achieve the maximum possible output allowed by its design, impeller selection and rotational speed. The following is a pump sizing problem to illustrate the calculations in this article. William mcnally has more than 45 years of experience with pumps and seals.