The addition of the head values of pumps operating in series is better suited to the steep. For two identical pumps in parallel the flowrate will double moving from 1 to 2 compared to a single pump if head is kept constant. The final example in this book combines parallel, series, and variable speed pumping for optimal energy savings. Practical centrifugal pumps is a comprehensive guide to pump construction, application, operation, maintenance and management issues. The flow system has the ability to test the pumps as a single unit or as a two pumps connected in series or parallel. Pumps are combined in series parallel to obtain an increase in head or flow rate. Hollander seriesparallel centrifugallpump filed april 26, 1938 6 sheetssheet 5 locaw hollander nventor a ttorvey. Publication date 1921 topics pumping machinery publisher london. When we say multiple pumps are in series, it means that. The experimental unit contains two identical centrifugal pumps and an intake tank with overflow. For fluid transfer applications, it is helpful to examine the energy required per million gallons of fluid pumped. It is the force performing on the liquid that makes to supply in the casing. Systems designed with several smaller pumps in parallel can use manual or automatic pump.
Series and parallel operation of centrifugal pumps free download as word doc. Apr 24, 20 by ron astall, united pumps australia centrifugal pumps are frequently operated in parallel to achieve higher system flows, to enhance system flexibility or to provide greater pump redundancy and hence better system availability. For those who want to do detail calculations, some examples have been included in the appendices. Centrifugal pumps fluid flow when the system characteristic curve is considered with the curve for pumps in parallel, the operating point at the intersection of the two curves represents a higher volumetric flow rate than for a single pump and a greater system head loss as shown in figure 12, a greater system head loss occurs with the increased fluid velocity resulting from the increased. A headcapacity curve of a centrifugal pump is said to be stable when the head curve rises steadily from high flow towards shutoff, i. For some piping system designs, it may be desirable to consider a multiple pump system to meet the design requirements. Characteristics of single pump and pumps in series and. Pumps operating in series pumps operating in parallel. The head, power input, and efficiency at constant speed n are plotted against the flow rate. For many young process engineers the concept of multiple centrifugal pumps in series or parallel is often confusing. Centrifugal pumps in series are used to overcome larger system head loss than one pump can handle alone. View and download ac fire pump 8100 series instruction manual online. How to select a centrifugal pump examples of total head calculations sizing a pump for a home owner application 14. How to operate centrifugal pumps in series or parallel.
Pumps can be arranged and connected in serial or parallel to provide additional head or flow rate capacity. Centrifugal pumps are used in series to overcome a larger system head loss than one pump can compensate for individually. Putting your centrifugal pumps in series, or connected along a single line, will let you add the head from each together and meet your high head, low flow system requirements. Lobanoff book aimed at the pump user, pump designer, rotatingequipment engineer, and student, this book bridges the gap between scholar texts and standard engineering design material. Pressures at inlet and outlet of the two pumps are displayed on manometers.
Centrifugal pumps, cavitation, impeller, npsh, cavitation. Pdf design, operation and refurbishment of centrifugal pumps are strongly related to. By ron astall, united pumps australia centrifugal pumps are frequently operated in parallel to achieve higher system flows, to enhance system flexibility or to provide greater pump redundancy and hence better system availability. First of all let us understand what it means by pumps in series and parallel. For very large projects, limited availability of sufficiently large pumps or limits on driver size or electrical starting current may dictate the use of multiple. Download practical centrifugal pumps design, operation. Smaller pumps may have a lower first cost and may also cost less to install, operate, and maintain. A compact, mobile and fully selfcontained centrifugal pump test set, that allows students to find the characteristics of centrifugal pumps working alone or in series or parallel. It also allows students to see and hear cavitation and understand the use of a venturi meter and differential pressure measurement to find flow rate. The objective of this experiment is to determine the operational characteristics of two centrifugal pumps when they are configured as a single pump, two pumps in series, and two pumps in parallel. B single operation, pumps a and b in parallel and series connections are illustrated in figures 2a, 2b, 2c and 2d respectively. Reliability of parallel and serial centrifugal pumps for dewatering in. Nov 12, 2012 centrifugal pumps in series and parallel 1.
As somebody has noted, the discharge capacities are to be matched. Although pumps run, most of the time, one at a time but sometimes two pumps are required to operate in parallel. Parallel pumping provides redundant capacity and the capabilityread more. The increase in pressure head can be used to carry water from one site to another site. We have expanded our energy efficient inline pump offering with 11 new close coupled and 11 new split coupled models.
Parallel pumping background pumps are described as operating in. When pumps are operating in series, the effects of pump failure is more serious than pumps which are set to operate in parallel. Effect of operating pumps in a series and b in parallel. The structure of a hydraulic machine, as a centrifugal pump, is evolved principally to satisfy the requirements of the fluid flow. One of these three pumps has different head than rest two pumps for same flow rate. Pumps operating in series pumps operating in parallel to connect two pumps in series means that the figure 15 presents a parallel configuration of discharge from the first pump is piped into the inlet two pumps. Centrifugal pumps pumps are machines that are used to transfer liquid from a location of low elevation to ahigher elevation. Parallel pumping background pumps are described as operating in parallel when they.
Hollander series parallel centrifugallpump filed april 26, 1938 6 sheetssheet 5 locaw hollander nventor a ttorvey. Series and parallel pumps free download as pdf file. Series and parallel operation of centrifugal pumps pump. For series connection, the discharge of one pump is connected to the suction side of the second pump, while for parallel connection both pumps are connected to a common discharge line. A centrifugal pump is a dynamic device that brings fluid into the center of the impeller the eye, the impeller slings it outward and forces it into a diverging section called a volute. Dec 14, 2012 for many young process engineers the concept of multiple centrifugal pumps in series or parallel is often confusing. Centrifugal pumps are often used together to enhance either the flow rate or the delivery pressure beyond that available from the single pump.
Centrifugal pumps designs and application by robert r. Centrifugal pumps in series allows for operation at lower speeds. H83 twostage series and parallel pumps a selfcontained. The results show that connecting the pumps in parallel gave a better.
Isbn 9789535100515, pdf isbn 9789535155720, published 20120224. Pumps are smaller, easier to maintain, and more manageable, versus a larger centrifugal pump. Download practical centrifugal pumps design, operation and. This resistance might be caused by the system or by the stationary pump b. The characteristic curves indicate the behavior of a pump under changing operating conditions. A typical example of this arrangement side of the second pump figure. A compact and mobile centrifugal pump test set for students to effectively see and hear cavitation and understanding the use of venturi meter. In order to illustrate the concept of parallel pumping, well use two pumps, each sized for onehalf of full system flow. It is a common industrial practice to run pumps in series whenever, the system head demands can not be met by a single pump. Pdf analysis on centrifugal pump performance in single. What is the harm of connecting two centrifugal pumps in. Fundamentals of fluid mechanics chapter 12 pumps and turbines. There is no math, just simple explanations of how pump systems work and how to select a centrifugal pump.
Centrifugal pumps in parallel are used to overcome larger volume flows than one pump can handle alone. Centrifugal pump problems 5 overview of pump problems typically found on centrifugal pumps. When a single pump is operating, the energy intensity ei is as follows. If, for example, there are three curves that are known for three centrifugal pumps and the resultant characteristic is required, the individual abscissae are added in the case of parallel connection, or the individual ordinates in the case of series connection. Download centrifugal pumps design and application by robert r.
The performance or characteristic curve of the pump. Parallel operation, or parallel pumping, of two centrifugal pumps is a mode which allows pump operation to be controlled by starting or stopping one of the two pumps. The following safety and common symbols may be used in this manual and on the equipment. Visit industrial site case studies downloads about us contact us work with us events videos blog.
The pumps are stainless steel fitted, matching the hydraulics and the flange to flange dimensions of the current pumps, with double the power in a compact footprint. Todays blog entry tries to explain the concept of centrifugal pumps in series and parallel. This is because the fluid pressure increases as the continuous flow passes through each pump, much like how a multistage pump works. 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. Use of existing equipment including possibility of using. The efficiency of a centrifugal pump can be defined as the ratio of the output power water to the input power shaft. When two or more pumps are arranged in serial their resulting pump performance curve is obtained by adding their heads at the same flow rate as indicated in the figure below centrifugal pumps in series are used to overcome larger system head loss than. Parallel pump details basic parallel pump installation figure 1 a simple example of two parallel pumps is shown in figure 1. The overflow ensures a constant suction head in the tank. Feb 20, 2014 c repeat the procedures as exercise b. Benefits of pumping in series with centrifugal pumps. What is total head 10 what is the relationship between head and total head 11.
A simple example of two parallel pumps is shown in figure 1. Centrifugal pumps fluid flow when the system characteristic curve is considered with the curve for pumps in parallel, the operating point at the intersection of the two curves represents a higher volumetric flow rate than for a single pump and a greater system head loss. Coverage includes pump classifications, types and criteria for selection, as well as practical information on the use of pumps, such as how to. Ball valves in the pipes allow easy switching between series and parallel operation.
This tutorial is intended for anyone that has an interest in centrifugal pumps. The series and parallel offer following advantages. When the pump cannot meet the required capacity it can use series and parallel pump circuits to. The impeller has a uniform blade length, b, of 2 in. Pumps and pumping system bureau of energy efficiency 118 figure 6. Series operation means that pumps are connected and started one after another, i. Pipe network characteristics 1 system with low resistance, 2 system with medium resistance, 3 system with large resistance operating behaviour and operating points of centrifugal pumps at the operating point the delivery pressure generated by the pump is in equilibrium with the. A compact, benchtop and fully selfcontained centrifugal pump test set, that allows students to find the characteristics of centrifugal pumps, working alone or in series or parallel. Each configuration single pump, two pumps in series, and two pumps in parallel will be tested at pump speeds of 60, 70, and 80 revsec.
The addition of the head values of pumps operating in series is better suited to the steep system characteristic curve than the addition of the flow rates in parallel operation. In practice the combined head and volume flow moves along the system curve. It also allows students to see and hear cavitation and understand the use of a venturi meter. However taking into account the strong interaction between the pump and the pumping. Centrifugal pumps an overview sciencedirect topics. The overflow ensures a constant suction head in the tank, regardless of the water supply. The connection of centrifugal pumps in series and parallel system assists in. This, in and of itself, has additional ancillary benefits. Fundamentals of fluid mechanics chapter 12 pumps and.
Practical centrifugal pumps design, operation and maintenance by the authors paresh girdhar, moni is a comprehensive guide to pump construction, application, working, maintenance and management issues. We have a set of three parallel centrifugal between bearing pumps for transfer of diesel. There are various types of pumps and they are classified in two major categories. Note that for two identical pumps in parallel, the. Ac fire pump 8100 series instruction manual pdf download. Important details like suction diffusers and isolation valves are not shown. If the failed pump is pump b, then pump a would suddenly have a serious system resistance causing its flowrate to be very low or even zero. Pumps operating in series p umps operating in parallel to connect two pumps in series means that the figure 15 presents a parallel configuration of discharge from the first pump is piped into the inlet two pumps. As illustrated in figure, two identical centrifugal pumps operating at the same speed with the same volumetric flow rate contribute the same pump head. Parallel and series pump application xylem applied water.