{"id":3348,"date":"2020-12-09T10:00:29","date_gmt":"2020-12-09T18:00:29","guid":{"rendered":"https:\/\/www.linquip.com\/blog\/?p=3348"},"modified":"2022-06-12T08:25:41","modified_gmt":"2022-06-12T16:25:41","slug":"what-is-pump-curve","status":"publish","type":"post","link":"https:\/\/www.linquip.com\/blog\/what-is-pump-curve\/","title":{"rendered":"Pump Curve: All You Should Know About Definition and Read One"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_83 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.linquip.com\/blog\/what-is-pump-curve\/#Pump_Curve_Chart\" >Pump Curve Chart<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.linquip.com\/blog\/what-is-pump-curve\/#Reading_a_Centrifugal_Pump_Curve\" >Reading a Centrifugal Pump Curve<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.linquip.com\/blog\/what-is-pump-curve\/#Pump_Curve_Equation\" >Pump Curve Equation<\/a><\/li><\/ul><\/nav><\/div>\n<p>A fluid flow system is identified with a chart named the\u00a0<strong><span data-preserver-spaces=\"true\">System Curve<\/span><\/strong><span data-preserver-spaces=\"true\">. A system curve, here we focus on pump curves, is a graphical presentation of the\u00a0<\/span><a href=\"https:\/\/www.sciencedirect.com\/topics\/engineering\/energy-equation\" target=\"_blank\" rel=\"noopener\"><span data-preserver-spaces=\"true\">Energy Equation<\/span><\/a><span data-preserver-spaces=\"true\">. In the previous decades, selecting a pump involved sitting down with massive printed catalogs and flipping over them until you reached a pump curve that fit your desired application. Today this process is made much more accessible employing electronic pump curve catalogs. One of the most popular Engineered Software for pump selection is\u00a0<\/span><a href=\"http:\/\/www.pump-flo.com\/\" target=\"_blank\" rel=\"noopener\"><span data-preserver-spaces=\"true\">pump-flo<\/span><\/a><span data-preserver-spaces=\"true\">, and another one is\u00a0<\/span><a href=\"http:\/\/www.intelliquip.com\/products\/intelliquip-selector\" target=\"_blank\" rel=\"noopener\"><span data-preserver-spaces=\"true\">Intelliquip<\/span><\/a><span data-preserver-spaces=\"true\">. To access various types of pumps and select the proper one, visit <a href=\"https:\/\/www.linquip.com\/equipment\/265\/centrifugal-pumps?category_id=265\">here<\/a>.<\/span><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Pump_Curve_Chart\"><\/span><strong>Pump Curve Chart<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Before we talk about the pump curve chart, we have to describe two distinct curves: <strong>System Curve<\/strong> and <strong>Pump Performance Curve<\/strong>.<strong>\u00a0<\/strong><\/p>\n<h3><strong>System Curve<\/strong><\/h3>\n<p>A\u00a0<strong><span data-preserver-spaces=\"true\">System Curve<\/span><\/strong>\u00a0is a graphical presentation of the Energy Equation.<\/p>\n<figure id=\"attachment_3349\" aria-describedby=\"caption-attachment-3349\" style=\"width: 399px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" class=\"wp-image-3349 size-full\" src=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.1.png\" alt=\"pump curve\" width=\"399\" height=\"210\" title=\"\" srcset=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.1.png 399w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.1-300x158.png 300w\" sizes=\"(max-width: 399px) 100vw, 399px\" \/><figcaption id=\"caption-attachment-3349\" class=\"wp-caption-text\">A typical system curve (Reference: <strong>engineeringtoolbox.com<\/strong>)<\/figcaption><\/figure>\n<p>The system head described in the above System Curve is a function of elevation or the static head. The primary and secondary losses in the system then can be expressed as:<\/p>\n<p style=\"text-align: center;\"><span class=\"katex-eq\" data-katex-display=\"false\">h=dh+{ h }_{ l }<\/span>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center;\"><span class=\"katex-eq\" data-katex-display=\"false\">in\\quad which<\/span>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center;\"><span class=\"katex-eq\" data-katex-display=\"false\">h=system\\quad head (m)<\/span>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center;\"><span class=\"katex-eq\" data-katex-display=\"false\">and<\/span>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center;\"><span class=\"katex-eq\" data-katex-display=\"false\">dh= { h }_{ 2 }-{ h }_{ 1 }= static\\quad head\\quad among\\quad inlet\\quad and\\quad outlet\\quad in\\quad the\\quad system<\/span>\n<p>&nbsp;<\/p>\n<p>Also, <span class=\"katex-eq\" data-katex-display=\"false\">{ h }_{l} <\/span> represents major and minor losses in the system, which has a generic expression as the following:<\/p>\n<p style=\"text-align: center;\"><span class=\"katex-eq\" data-katex-display=\"false\">{ h }_{l}=k{ q }^{ 2 } <\/span>\n<p>&nbsp;<\/p>\n<p>where\u00a0 <span class=\"katex-eq\" data-katex-display=\"false\">q<\/span>\u00a0 is the flow rate, and\u00a0 <span class=\"katex-eq\" data-katex-display=\"false\">k<\/span>\u00a0 is a constant representing characteristics of the system, including major and minor losses.<\/p>\n<h3><strong>Pump Performance Curve<\/strong><\/h3>\n<p>The basic pump curve is something similar to the following figure:<\/p>\n<figure id=\"attachment_3350\" aria-describedby=\"caption-attachment-3350\" style=\"width: 331px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" class=\"wp-image-3350 size-full\" src=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.2.jpg\" alt=\"pump curve\" width=\"331\" height=\"306\" title=\"\" srcset=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.2.jpg 331w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.2-300x277.jpg 300w\" sizes=\"(max-width: 331px) 100vw, 331px\" \/><figcaption id=\"caption-attachment-3350\" class=\"wp-caption-text\">A typical pump curve (Reference: <strong>rcworst.com<\/strong>)<\/figcaption><\/figure>\n<p>Each kind of pump has a distinct chart, and the data outlined on them also diversifies with the model.<\/p>\n<p>The first impression that should be noticed is that pressure, which represents the head, typically appears on the main vertical Y-axis. On the horizontal X-axis, we ordinarily have the flow rate, describing how much water a pump can transfer.<\/p>\n<figure id=\"attachment_3351\" aria-describedby=\"caption-attachment-3351\" style=\"width: 430px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" class=\"wp-image-3351 size-full\" src=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.3.jpg\" alt=\"pump curve\" width=\"430\" height=\"430\" title=\"\" srcset=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.3.jpg 430w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.3-300x300.jpg 300w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.3-150x150.jpg 150w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.3-420x420.jpg 420w\" sizes=\"(max-width: 430px) 100vw, 430px\" \/><figcaption id=\"caption-attachment-3351\" class=\"wp-caption-text\">A typical head-flow ratel pump curve (Reference: <strong>tsurumipump.com<\/strong>)<\/figcaption><\/figure>\n<p>Besides the typical head-flow rate pump curve, there are other curves with essential information for selecting a proper pump, such as\u00a0<a href=\"https:\/\/www.pumpsandsystems.com\/pumps\/reading-centrifugal-pump-curve#:~:text=Efficiency%20curve%3A%20The%20pump%20efficiency%20curve%20represents%20a,away%2C%20either%20right%20or%20left%2C%20from%20the%20BEP.\" target=\"_blank\" rel=\"noopener\"><span data-preserver-spaces=\"true\">efficiency curves<\/span><\/a><span data-preserver-spaces=\"true\">,\u00a0<\/span><a href=\"https:\/\/www.engineeringtoolbox.com\/affinity-laws-d_408.html\" target=\"_blank\" rel=\"noopener\"><span data-preserver-spaces=\"true\">pump curves for several impeller diameters and various speeds<\/span><\/a><span data-preserver-spaces=\"true\">,\u00a0<\/span><a href=\"https:\/\/www.pumpsandsystems.com\/performance-curves-and-npsh-tests\" target=\"_blank\" rel=\"noopener\"><span data-preserver-spaces=\"true\">NPSHr curve<\/span><\/a><span data-preserver-spaces=\"true\">, and\u00a0<\/span><a href=\"https:\/\/www.engineeringtoolbox.com\/horsepower-d_472.html\" target=\"_blank\" rel=\"noopener\"><span data-preserver-spaces=\"true\">power consumption<\/span><\/a><span data-preserver-spaces=\"true\">.<\/span><\/p>\n<p>Raising the impeller diameter or speed boosts the head and flow rate capacity, so the pump curve shifts upwards.<\/p>\n<p>The head capacity can be enhanced by joining two or more pumps in series, or the flow rate capacity can be improved by joining two or more pumps in parallel.<\/p>\n<h3><strong>Selection of a Proper Pump<\/strong><\/h3>\n<p>The decent pump can be chosen by combining the System Curve and the Pump Curve:<\/p>\n<figure id=\"attachment_3352\" aria-describedby=\"caption-attachment-3352\" style=\"width: 410px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" class=\"wp-image-3352 size-full\" src=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.4.png\" alt=\"pump curve\" width=\"410\" height=\"214\" title=\"\" srcset=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.4.png 410w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.4-300x157.png 300w\" sizes=\"(max-width: 410px) 100vw, 410px\" \/><figcaption id=\"caption-attachment-3352\" class=\"wp-caption-text\">Combining a system curve with the pump curve (Reference: <strong>engineeringtoolbox.com<\/strong>)<\/figcaption><\/figure>\n<p>The operating point is wherever the system curve and the actual pump curve meets.<\/p>\n<p>There are some definitions of the points and operating conditions where a pump operates. Here are some definitions:<\/p>\n<h4><strong><em>Best Efficiency Point \u2013 BEP\u00a0<\/em><\/strong><\/h4>\n<p>The best-operating states will, in common, be close to the Best Efficiency Point (<em><span data-preserver-spaces=\"true\">BEP)<\/span><\/em>. Specific attention should be taken for applications where system conditions frequently fluctuate during operation, like applications for air conditioning and heating systems or water supply systems with changeable consumption and modulating valves.<\/p>\n<h4><span style=\"font-family: verdana, geneva, sans-serif;\"><strong><em>Carry Out<\/em><\/strong><\/span><\/h4>\n<p>When a pump operates in the far right of its curve with low efficiency, then the pumps Carry Out.<em>\u00a0<\/em><\/p>\n<h4><span style=\"font-family: verdana, geneva, sans-serif;\"><strong><em>Shutoff Head<\/em><\/strong><\/span><\/h4>\n<p>The Shutoff Head is the head provided when the pump works with fluid but with no flow rate.<\/p>\n<h4><span style=\"font-family: verdana, geneva, sans-serif;\"><strong><em>Churn<\/em><\/strong><\/span><\/h4>\n<p>A pump is in Churn when it runs at shutoff head or no flow.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Reading_a_Centrifugal_Pump_Curve\"><\/span><strong>Reading a Centrifugal Pump Curve<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Centrifugal Pump curves present eight critical factors that are crucial in selecting the right pump for a specific operating condition. These factors include Flow, Head, Efficiency, Impeller Trim Diameter, NPSHR, Power, MCSF (Minimum Continuous Stable Flow), and RPM. The Pump curve also represents the Pump model, the Pump size, and the number of stages for multi-stage pumps.<\/p>\n<p><span data-preserver-spaces=\"true\">The Pump curve displays the Flowrate range on the horizontal axis. As typical, the Flowrate range varies between zero flow to 20% past the Best Efficiency Flow. The point at zero flow is attributed to as \u201cShut Off\u201d, and the last point at maximum flow is designated as \u201cRun Out\u201d.<\/span><\/p>\n<p><span data-preserver-spaces=\"true\">The vertical scale on the primary curve is always a differential head. Differential Head, which is often mentioned as \u201cHead\u201d or \u201cTotal Dynamic Head\u201d, is a universal method of quantifying the pressure the pump can develop. Since pressure is relative to the working fluid density, all pump curves essentially present this metric in a length unit (FT or Meters). This causes the pump curve suitable for most liquid types. Exemptions are liquids with high viscosity or solid particles.<\/span><\/p>\n<p><span data-preserver-spaces=\"true\">Most<a href=\"https:\/\/www.youtube.com\/watch?v=lmjIQqo8mX4\" target=\"_blank\" rel=\"noopener\">\u00a0centrifugal pumps<\/a>\u00a0are identified by an elliptical head curve, which is at &#8220;Shut Off&#8221; and &#8220;Run Out&#8221; points.<\/span><\/p>\n<p><span data-preserver-spaces=\"true\">Once the Rated Flow is outlined vertically, and the Rated Head is plotted horizontally, where the two points coincide, Rated Duty Point is ordinarily given as a triangle. Here is a pump Curve demonstrating Flow, Head, HP, NPSHR, Efficiency, Impeller diameter, and the MCSF.<\/span><\/p>\n<figure id=\"attachment_3353\" aria-describedby=\"caption-attachment-3353\" style=\"width: 700px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" class=\"wp-image-3353 size-full\" src=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.5.png\" alt=\"pump curve\" width=\"700\" height=\"488\" title=\"\" srcset=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.5.png 700w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.5-300x209.png 300w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.5-696x485.png 696w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.5-602x420.png 602w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.5-100x70.png 100w\" sizes=\"(max-width: 700px) 100vw, 700px\" \/><figcaption id=\"caption-attachment-3353\" class=\"wp-caption-text\">Single speed curve of a pump and demonstrating various parameters (Reference: <strong>pumpsandsystems.com<\/strong>)<\/figcaption><\/figure>\n<h3><strong>A Centrifugal Pump Curve Elements<\/strong><\/h3>\n<p>To explain, consider the subsequent example and refer to the single-speed curve displayed in the above figure:<\/p>\n<ul>\n<li><span data-preserver-spaces=\"true\">A flow of 9,000 GPM<\/span><\/li>\n<li><span data-preserver-spaces=\"true\">A head of 180 feet<\/span><\/li>\n<\/ul>\n<p><span data-preserver-spaces=\"true\">Find 9,000 GPM on the horizontal axis, and follow it up until it meets with 180 feet of head on the vertical axis. The intersection point will fall toward the middle of the curve and probably within the <a href=\"https:\/\/www.introtopumps.com\/pump-terms\/por-preferred-operating-range\/#:~:text=The%20preferred%20operating%20range%2C%20or%20POR%2C%20is%20a,continuous%20operating%20conditions%20should%20be%20located%20if%20possible.\" target=\"_blank\" rel=\"noopener\">preferred operating region (POR)<\/a>, causing the pump the right option for this sample application.<\/span><\/p>\n<p><span data-preserver-spaces=\"true\">It would be essential to prove that it does, in fact, fall inside the POR by examining the manufacturer\u2019s guidelines.<\/span><\/p>\n<p><span data-preserver-spaces=\"true\">The same graph can describe how the pump\u2019s performance will vary if the impeller diameter is diminished or expanded. The diameter is shown in inches neighboring its corresponding curve. A shift in impeller diameter does not alter the system curve, which only shifts if a system head changes, such as a closed valve. The intersection points are where the pump operates at each diameter.<\/span><\/p>\n<p><span data-preserver-spaces=\"true\">Note that it is possible to change the impeller diameter and system conditions, so long as the pump performance still comes within the POR. There is a wider range of the pump curve recognized as the allowed operating region (AOR), in which it may be authorized and profitable to operate the pump. It usually lies between the minimum continuous stable flow (MCSF) line and the runout line. If pump performance falls outside that zone, then another pump should be selected.<\/span><\/p>\n<h3><strong>Other Pump Curve Elements<\/strong><\/h3>\n<p>A pump curve graph presents other elements necessary for determining the correct product for a specific operating condition.<\/p>\n<h4><em>Efficiency curve<\/em><\/h4>\n<p><span data-preserver-spaces=\"true\">The pump efficiency curve describes a pump\u2019s efficiency over its whole operating range. Efficiency is represented in percentages on the right side of the curve graph. The efficiency curve\u2019s peak characterizes the BEP, with efficiency diminishing as the curve arcs away, either right or left, from the BEP. Understanding the efficiency percentage will also help estimate the horsepower needed for an application.<\/span><\/p>\n<h4><em>ISO efficiency lines<\/em><\/h4>\n<p><a href=\"https:\/\/www.iso.org\/home.html\" target=\"_blank\" rel=\"noopener\"><span data-preserver-spaces=\"true\">International Organization for Standardization (ISO)<\/span><\/a><span data-preserver-spaces=\"true\">\u00a0lines are elliptical curves designating identical efficiency on a pump curve graph. They are used to represent how efficiency levels vary along a pump curve as it goes away from the BEP or if the impeller diameter is decreased.<\/span><\/p>\n<h4><em>Power curve<\/em><\/h4>\n<p><span data-preserver-spaces=\"true\">The power curve depicts the load the pump forces on the driver at a provided point on the pump curve and assists with proper motor sizing. It is designated as a separate curve graph and progressively rises toward its peak load, typically close to the BEP with most rotodynamic pump models. Thereafter, it diminishes as it approaches the runout point.<\/span><\/p>\n<h4><em>Net positive suction head curve<\/em><\/h4>\n<p><span data-preserver-spaces=\"true\">The net positive suction head required (NPSHr) shows how much force is required to force liquid into the pump impeller&#8217;s eye. It is presented in feet below the main pump curve graph. Understanding the correct amount of NPSHr will restrict the pump from\u00a0<a href=\"https:\/\/www.rodelta.com\/pump-cavitation\/#:~:text=Pump%20cavitation%20is%20the%20phenomenon%20that%20in%20a,Liquids%20in%20impellers%20can%20flow%20at%20high%20speeds.\" target=\"_blank\" rel=\"noopener\">cavitating<\/a>, vibrating, and failing prematurely.<\/span><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Pump_Curve_Equation\"><\/span><strong>Pump Curve Equation<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Engineers commonly use the Hazen-Williams equation for major losses to design and analyze piping systems carrying water at normal temperatures of city water supplies (40 to 75 <sup>o<\/sup>F; 4 to 25 <sup>o<\/sup>C). A pump curve is included in the calculation to simulate flows comprising centrifugal pumps or other pumps with a pump curve. Two points are typically required on the pump curve, including flow at zero head and head at zero flow and also information particularly about the pipe on the suction side of the pump to compute the net positive suction head available (NPSHA). For a pump to function correctly, the NPSHA must be larger than the NPSH needed by the pump (obtained from the pump manufacturer).<\/p>\n<h3><strong>Equations and Methodology<\/strong><\/h3>\n<p>The calculation on this page utilizes the steady-state energy equation. Major losses (as a result of pipe friction) and minor losses (due to valves, pipe bends, etc.) are included in this calculation. The Hazen-Williams equation for friction losses is employed. The equations are conventional equations that can be discovered in most fluid mechanics textbooks. A pump curve is involved in the calculation. The procedure of pump determination in a typical pump selection software is as the following:<\/p>\n<ol>\n<li>The user must enter the two extreme points on the curve: head when capacity is zero and capacity when the head is zero.<\/li>\n<li>Then, a parabola with a negative curvature is fit within the two points. This parabola is applied since it is a proper approximation of a standard pump curve and does not want users to enter a multitude of data points. Note that, often, pump catalogs only give the two extreme points on the curve rather than a graph showing the complete curve.<\/li>\n<\/ol>\n<figure id=\"attachment_3354\" aria-describedby=\"caption-attachment-3354\" style=\"width: 569px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" class=\"wp-image-3354 size-full\" src=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.-6.jpg\" alt=\"pump curve\" width=\"569\" height=\"419\" title=\"\" srcset=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.-6.jpg 569w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.-6-300x221.jpg 300w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2020\/11\/Fig.-6-80x60.jpg 80w\" sizes=\"(max-width: 569px) 100vw, 569px\" \/><figcaption id=\"caption-attachment-3354\" class=\"wp-caption-text\">Schematic view of a pipe and pump system (Reference: <strong>lmnoeng.com<\/strong>)<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>At what follows, some basic equations regarding pump selection is provided:<\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center;\"><span class=\"katex-eq\" data-katex-display=\"false\">H+{ Z }_{ 1 }-{ Z }_{ 3 }+\\frac { { P }_{ 1 }-{ P }_{ 3 } }{ S } +\\frac { { { V }_{ 1 } }^{ 2 }-{ { V }_{ 3 } }^{ 2 } }{ 2g } ={ h }_{ f }+{ h }_{ m }<\/span>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center;\"><span class=\"katex-eq\" data-katex-display=\"false\">Where<\/span>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center;\"><span class=\"katex-eq\" data-katex-display=\"false\">{ h }_{ f }=L{ \\left[ \\frac { V }{ kC } { (\\frac { 4 }{ D } ) }^{ 0.63 } \\right] }^{ 1\/0.54 }\\quad \\quad \\quad \\quad \\quad { h }_{ m }=k\\frac { { V }^{ 2 } }{ 2g } ,\\quad Q=VA,\\quad A=\\frac { \\pi }{ 4 } { D }^{ 2 }<\/span>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center;\"><span class=\"katex-eq\" data-katex-display=\"false\"> H={ H }_{ max }\\left[ 1-{ \\left( \\frac { Q }{ { Q }_{ max } } \\right) }^{ 2 } \\right] ,\\quad Equation\\quad used\\quad for\\quad pump\\quad curve<\/span>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center;\"><span class=\"katex-eq\" data-katex-display=\"false\">NPSH={ Z }_{ 1 }-{ Z }_{ 2 }+\\frac { P_{ 1 }+P_{ atm }-P_{ v } }{ S } +\\frac { { { V }_{ 1 } }^{ 2 } }{ 2g } -{ h }_{ fA }-{ h }_{ mA }<\/span>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center;\"><span class=\"katex-eq\" data-katex-display=\"false\">{ h }_{ fA }={ L }_{ A }{ \\left[ \\frac { V }{ kC } { \\left( \\frac { 4 }{ D } \\right) }^{ 0.63 } \\right] }^{ 1\/0.54 },\\quad \\quad \\quad \\quad { h }_{ mA }={ k }_{ A }\\frac { { V }^{ 2 } }{ 2g } <\/span>\n<p>&nbsp;<\/p>\n<div class=\"su-box su-box-style-default\" id=\"\" style=\"border-color:#0f0f0f;border-radius:3px;max-width:none\"><div class=\"su-box-title\" style=\"background-color:#424242;color:#f2b225;border-top-left-radius:1px;border-top-right-radius:1px\">Variable Equations<\/div><div class=\"su-box-content su-u-clearfix su-u-trim\" style=\"border-bottom-left-radius:1px;border-bottom-right-radius:1px\">\n<p><strong>The variables utilized in the above equations are as the following:<\/strong><\/p>\n<p><em>A<\/em><span data-preserver-spaces=\"true\">\u00a0= Pipe area.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">C<\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Hazen-Williams coefficient.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">D<\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Pipe inside diameter.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">D<sub>H<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Driving Head.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">g<\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Gravitational acceleration.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">h<sub>f<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Major losses for the entire pipe.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">h<sub>fA<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Major losses for pipe upstream of the pump.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">h<sub>m<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Minor losses for the entire pipe.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">h<sub>mA<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Minor losses for pipe upstream of the pump.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">H<\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Total dynamic head.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">H<sub>max<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Maximum head that the pump can provide.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">k<\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Unit conversion factor = 0.85 for Metric units.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">K<\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Sum of minor loss coefficients for the entire pipe.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">K<sub>A<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Sum of minor loss coefficients for pipe upstream of the pump.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">L<\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Total pipe length.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">L<sub>A<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Length of pipe upstream of the pump.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">NPSH<sub>A<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Net positive suction head available.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">P<sub>atm<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Atmospheric (or barometric) pressure [P].<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">P<sub>v<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Vapor pressure of the fluid.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">P<sub>1<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Gage pressure at the surface of a reservoir open to the atmosphere, or the pressure in a supply main like a tank under pressure.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">P<sub>1<\/sub>-P<sub>3<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Pressure difference between points 1 and 3.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">Q<\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Flowrate.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">Q<sub>max<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Maximum flow rate on the pump curve.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">S<\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Specific Weight of Water.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">V<sub>1<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Velocity of fluid at location 1.\u00a0<em>V<sub>1<\/sub><\/em>\u00a0is automatically computed as\u00a0<em>Q\/A<\/em>.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">V<sub>3<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Velocity of fluid at location 3.\u00a0<em>V<sub>3<\/sub><\/em>\u00a0is automatically calculated as\u00a0<em>Q\/A<\/em>.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">Z<sub>1<\/sub>-Z<sub>2<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Deiffernece among elevation of location 1 and elevation of the pump.<\/span><\/p>\n<p><em><span data-preserver-spaces=\"true\">Z<sub>1<\/sub>-Z<sub>3<\/sub><\/span><\/em><span data-preserver-spaces=\"true\">\u00a0= Differnece between elevation of location 1 and elevation of location 3.<\/div><\/div><\/span><\/p>\n<h3><b>Buy Equipment or Ask for a Service<\/b><\/h3>\n<p>By using Linquip RFQ Service, you can expect\u00a0to receive quotations from various suppliers across multiple industries and regions.<\/p>\n<p style=\"text-align: center;\"><strong><a href=\"http:\/\/linquip.com\/get-quote?utm_source=blog&amp;utm_medium=content&amp;utm_campaign=product_list&amp;utm_term=product_list&amp;utm_content=rfq\" target=\"_blank\" rel=\"noopener\">Click Here to Request a Quotation From Suppliers and Service Providers<\/a><\/strong><\/p>\n<p><em><strong>Read More on Linquip<\/strong><\/em><\/p>\n<ul>\n<li><span style=\"text-decoration: underline;\"><strong><span style=\"font-size: 10pt;\"><a title=\"Types of Pump Casings (In Centrifugal Pumps &amp; Others) + Pros &amp; Cons\" href=\"https:\/\/www.linquip.com\/blog\/types-of-pump-casings\/\" target=\"_blank\" rel=\"noopener\">Types of Pump Casings (In Centrifugal Pumps &amp; Others) + Pros &amp; Cons<\/a><\/span><\/strong><\/span><\/li>\n<li><span style=\"text-decoration: underline;\"><strong><span style=\"font-size: 10pt;\"><a title=\"What Is Pump Cavitation\" href=\"https:\/\/www.linquip.com\/blog\/what-is-pump-cavitation\/\" target=\"_blank\" rel=\"noopener\" data-schema-attribute=\"\">What Is Pump Cavitation<\/a><\/span><\/strong><\/span><\/li>\n<li><span style=\"text-decoration: underline;\"><strong><span style=\"font-size: 10pt;\"><a title=\"What is Hydraulic Pump: Learn The Basics, Boost Your Knowledge\" href=\"https:\/\/www.linquip.com\/blog\/what-is-hydraulic-pump\/\" target=\"_blank\" rel=\"noopener\">What is Hydraulic Pump: Learn The Basics, Boost Your Knowledge<\/a><\/span><\/strong><\/span><\/li>\n<li><span style=\"text-decoration: underline;\"><strong><span style=\"font-size: 10pt;\"><a title=\"How Does a Hydraulic Pump Work? A Definitive Guide\" href=\"https:\/\/www.linquip.com\/blog\/hydraulic-pump-working-principles\/\" target=\"_blank\" rel=\"noopener\">How Does a Hydraulic Pump Work? A Definitive Guide<\/a><\/span><\/strong><\/span><\/li>\n<li><span style=\"text-decoration: underline;\"><strong><span style=\"font-size: 10pt;\"><a title=\"Different Types of Hydraulic Pumps: a Complete Guide\" href=\"https:\/\/www.linquip.com\/blog\/different-types-of-hydraulic-pumps\/\" target=\"_blank\" rel=\"noopener\">Different Types of Hydraulic Pumps: a Complete Guide<\/a><\/span><\/strong><\/span><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>A fluid flow system is identified with a chart named the\u00a0System Curve. A system curve, here we focus on pump curves, is a graphical presentation of the\u00a0Energy Equation. In the previous decades, selecting a pump involved sitting down with massive printed catalogs and flipping over them until you reached a pump curve that fit your &#8230;<\/p>\n","protected":false},"author":11,"featured_media":3355,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","footnotes":""},"categories":[23],"tags":[],"class_list":["post-3348","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-pump"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/posts\/3348","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/comments?post=3348"}],"version-history":[{"count":2,"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/posts\/3348\/revisions"}],"predecessor-version":[{"id":18213,"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/posts\/3348\/revisions\/18213"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/media\/3355"}],"wp:attachment":[{"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/media?parent=3348"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/categories?post=3348"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/tags?post=3348"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}