Dimensionless curves of centrifugal pumps for water supply. Estimation of power consumption by centrifugal pump with. Pdf equations correct centrifugal pump curves for viscosity. Armstrong limited 23 bertrand avenue toronto, ontario canada, m1l 2p3 t. This is known as a non overloading motor selection. Compared to the original impeller with no cut, one can see that all cuts produce less pump head due to. The operating point of a centrifugal pump, also called its duty point, is given by the intersection of the pump characteristic curve with the system curve. Pump performance curves what is the pump performance curve used for. The performance of a centrifugal pump is shown by a set of performance curves. Reading and understanding centrifugal pump curves is key to proper pump selection, and to their reliable.
This set of four curves is known as the pump characteristic curves or pump performance curves. Lesson 28 characteristic curves of centrifugal pumps. Why does a centrifugal pump produce less flow at high pressure and more flow at low pressure. A pump curve provides a wealth of information regarding the performance capabilities of a pump.
A typical composite curve includes the pump performance curves, horsepower curves and npsh required. The programme predicts the overall headcapacity characteristic of the pump and also gives separately the losses occurring in the pump. The characteristic curves of centrifugal pumps plot the course of the following parameters against flow rate q. These four curves velocity head relate head, efficiency, power, and net positive sucvelocity head is the amount of energy required tion head required to pump capacity figure 3. Understanding centrifugal pump curves when selecting a centrifugal pump, one should match the performance of the pump to that needed by the system. The centrifugal pump performance curve consists of four set of curves. In addition, pump performance curves can be constructed from the experimental data obtained by savar et al. The affinity laws, or the pump laws, state how such changes influence the performance of the pump. Performance curves for different pumps can only be compared if they are stated with the same speed.
Taco 1600 series inline pumps combine the ultimate in reliability with ease of installation. Head versus capacity power versus capacity npsh versus capacity. To change the operating point either the system curve or the pump curve must be changed. Details about centrifugal pump characteristic curve. Understanding of centrifugal pump performance curve is very important for select a proper pump for the required application. The flow rate q and the developed head h are both determined by the intersection. Pump performance curves show this interrelation of pump head. Theory one way of illustrating pump characteristics is to construct contour lines of. Overal pump performance and unsteady pressure pulsation.
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. Flow, head, impeller trim diameter, efficiency, power, npshr, mcsf minimum continuous stable flow and rpm. Pump characteristic curves also offer the opportunity to establish the optimum solution to operate the pumppumps at or closest to the bep as well as ascertain the implication of operating away from the bep. Pump model page number pump model page number 32 2 65 16 32160 3 65160 17 32200 4 65200 18 32260 5 65260 19.
The yield of the motorpump set is directly related to the. On the centrifugal pumps performance curves estimation. Pump performance curve important points shutoff head is the maximum pressure or head the pump can produce no flow is produced pump flow rate head shutoff head. The conto if the right hand end of the heau capacity curves depends on the dynamic suction lift. Centrifugal pumps pump curves real pumps are never ideal and the performance of the pumps are determined experimentally by the manufacturer and typically given in terms of graphs or pump curves. Pump performance curves ef 04w2 ef 04w2 60hz 3480 rpm discharge frequency 2 reference curve curve number rated power hydraulic efficiency 62. Certrifugal pump reciprocating pump schematic diagram characteristic curve is essential. A comparative study on centrifugal pump designs and two. The characteristic curve s shape is primarily determined by the pump type i. The pump performance curve, also referred to as performance data, helps you in correctly advising customers. Pdf dimensionless characteristics of centrifugal pump. Curves relating total head, efficiency, power, and net positive suction head required npshr to discharge or pump capacity q are utilized to describe the operating properties characteristics of a pump.
Pump manufacturers use the terminology called head and pump users use pressure to measure the performance. Centrifugal pump performance curves part 2 youtube. Results and discussion the proposed methodology has been initially tested to estimate the performance of conventional pumps. Parallel and series pump application xylem applied water systems. A pump curve is a graphical representation of the performance characteristics of a pump. Centrifugal pump exercise b objective to create head, power and efficiency characteristic curves for a centrifugal pump.
Pump performance curves generally show performance for various impeller diameters or trims. Whats the significance of pump characteristic curves. Pump performance curves are generated by conducting water tests on pump and impeller combinations. Effect of blade exit shape on performance and vibration of. A curve is defined for a specific operating speed rpm and. To do that, an engineer would refer to a pumps composite curve. A pump performance curve indicates how a pump will perform in regards to pressure head and flow. It shows the relationship between the flowrate q and the delivery head h of a pump. Reading centrifugal pump curves national environmental. Head, power consumption, efficiency and npsh are shown as a function of the flow. Pump performance curves at different impeller blade exit cuts.
It is not necessary to design specific pump for each specific system. The curves in both figures showchanges in agiven parameter as afunction ofcapacity. The pump curve also displays the pump model, the pump size and number of stages for multistage pumps. It is good practice to select a pump with an impeller. On xy plot, head is plotted in y axis and the flow is plotted in x axis. Lets first go through the characteristic curves of centrifugal and reciprocating pump so that the ones referring it for the first time also get the idea of it.
Ese01061en 1507 alfa laval reserves the right to change specifications without prior. Pump curves and other product data in this bulletin are for illustration only. Pump curves for hydronic circulators always show the head energy added along the vertical axis and the flow rate through the circulator on the horizontal axis. For systems pump manufacturers normally publish a set of with a high total head this. Pump performance curves ef 05w2 ef 05w2 60hz 3480 rpm discharge frequency 2 reference curve curve number rated power hydraulic efficiency 62. Performance curve book din24255 pumps 1450rpm pump model page number pump model page number 32 2 80260 23 32160 3 80320 24 32200 4 80400 25 32260 5 100160 26 40 6 100200 27 40160 7 100260 28. A centrifugal pump performance curve is produced by a pump manufacturer from actual tests performed and shows the relationship between flow and total dynamic head, the efficiency, the npsh required, and the bhp required. In centrifugal pumps the delivery head h depends on the flow rate q. The centrifugal pump is a very capable and flexible machine. If clear flow impeller is mounted the performance can be up to 10% lower than on the curves shown. The pump manufacturer decides to design a new, larger pump for other applications, e. This paper describes the technique of determining the complete operating characteristics of a hydraulic machine such as a centrifugal pump or a turbine, together with a. The performance curves for a centrifugal pump are shown in figure 1. Manufacturers will put several different trim curves on a pump performance curve to make pump specification easier, although this sometimes makes the pump performance curve more difficult to read.
Shut off head is the head developed by the pump at zero flow. Pump curves are a diagnostic tool, for establishing pump performance in an operating system. Every pump curve has a best efficiency point bep at any given impeller trim. Selecting a centrifugal pump by system analysis 2012 instructor. General examples ofthese curves are shown in figure 1. The performance of centrifugal pump can be changed by the change in impeller diameter or its rotational speed. The curves can be converted to the same speed by the formulas of affinity laws, which will also be explained later. Centrifugal pump performance curves and technical information 0 20 40 60 80 100 120 140 0 10 20 30 40 50 60 70 80 0 100 110 capacity ead ft nps in feet 10 20 30 40 50 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000 160 npsh req u i r e d 2 5 0 m i mp e l r dia t r 9 16 45 h e a d c a p a c i t y 0 5 10 15 20 25 30 35 40 gpm lbs. To read pump system curve and operating points click here. When selecting a pump, use a pump curve to ensure that its primary operating range falls within or near its best efficiency range. To select a proper pump for a particular application it is necessary to utilize the system curve and the pump performance curve. Prediction of performance characteristics of a centrifugal. Equations correct centrifugal pump curves for viscosity article pdf available in oil and gas journal 9822. Pump performance curves and matching a pump to a piping.
Centrifugal pump curves show 8 important factors that are critical in selecting the right pump for your application. During a bench test, the pump is operated at constant speed and the values q and h are. Other information presented in the manufacturers curves are the yield, the ratio between the energy supplied to the duty fluid net power and the energy supplied to the axis of its rotor motor power gomes, 2009. Ashrae recommends pump selection between 66% to 115% of flow at bep, though 85% to 105% of flow is the preferred range. Pump performance curves oxygen, nitrogen, argon, carbon dioxide, methane lng liquids pumped cp 1804. The pump curves start at a high point on the left side of the graph called the shut off head. Before we start first we will understand the basics of centrifugal pump performance curve. Information is plotted on an xy graph where the xaxis is measured in units of flow and the yaxis is measured in units of head, power, and npshr. Reading centrifugal pump curves environmental finance center. This relationship, also called pump performance, is illustrated by curves. Centrifugal pump performance curves and technical information. Determining the operating point example the pump should displace water 1 m.
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