# pump efficiency affinity law

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• ### Centrifugal Pump Affinity Laws Calculation - Chemical ...

The affinity laws are a set of forumlas that predict the impact of a change in rotational speed or impeller diameter on the head and flow produced by a pump and power demanded by a pump. If you know the shape of a pump performance curve at a certain speed or with a certain impeller diameter, you can use the affinity laws to predict the performance ...

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• ### Pump Affinity Laws - Engineering ToolBox

2021-5-6 · The Pump affinity laws are basically a set of formulas that predict the impact of Change in Pump impeller Diameter and its Rotational Speed on the Pump Head (h), Pump Flow (Q), and Power Demand of the Pump (P). Pump affinity laws or Pump Laws are used during hydraulic design to calculate the volume, capacity, head, or power consumption of the centrifugal pumps with changing speed or …

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• ### Affinity Laws | Intro to Pumps

This research is a continuation of efforts aimed at establishing the modified affinity laws for viscosity to predict the pump performance directly from a plot in terms of dimensionless numbers i.e....

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• ### How To Use Affinity Laws to Calculate A New Best ...

2013-5-31 · The Affinity Laws govern the performance of your pumps. The laws will help you extrapolate and predict pump performance at different velocities. They are also useful to modify your pumps for new and different required duties.

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• ### What Are The Pump Affinity Laws? Explanation with a

2006-11-6 · This recirculation or “repumping”, as it could be called, reduces the hydraulic efficiency of the pump. The accuracy of the affinity laws is also sacrificed with this reduction in efficiency. According to the affinity laws, the 6-in impeller should produce a BEP flow of 466-GPM at a head of 111-ft; however, as you can see, its flow is just 400- GPM @ 84-ft.

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• ### (PDF) Efficiency Prediction of Centrifugal Pump Using

2018-7-12 · Affinity Laws to predict the performance of a single stage pump or the stage by stage performance of a multi stage pump operating with gas and varying viscosity. INTRODUCTION . The performance of a pump changes significantly with pump speed, fluid density, fluid viscosity, and the presence of gas.

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• ### Cheat Sheets: The Affinity Laws - Empowering Pumps

Pump Curve Speed Calculator This centrifugal pump curve calculator is meant to quickly calculate the different operating conditions when a centrifugal pump is sped up or slowed down. Using affinity laws, we can accurately calculate the pressure, flow and required speed and power of a pump from a specific known set point.

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• ### Pump Affinity Laws - Crest Pumps

This law is expressed with the following formula: P 1 /P 2 = (N 1 /N 2) 3 or (D 1 /D 2) 3. Where P is equal to power, N is equal to shaft speed, and D is equal to impeller diameter. Use of the Affinity Laws. The affinity laws will produce highly accurate results when predicting the impact of changes in speed.

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• ### Pump affinity laws | KSB

The affinity laws for centrifugal pumps state that the H/Q curves at various rotational speeds can be derived from the following relationship as conventionally represented:. Q Flow rate H Head Y Specific energy n Rotational speed. If P Q = ρ · g · Q · H (see Pump power output) and P = PQ η (see Pump power input), and assuming a constant density (ρ) of the fluid handled and a constant ...

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• ### Pump Affinity Law Calculator - Pipeng Toolbox

Pump Affinity Or Similarity Law Calculation Module . ... Pump efficiency scaling should be combined with flowrate scaling. Pump efficiency varies with flowrate. A known pump can be scaled to operate at the best efficiency point (BEP) with a required design flow rate and delta pressure using the affinity laws. The pump curve is calculated using ...

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• ### Affinity laws | KSB

The relationships established between the physical quantity of the original and that of the model by means of the characteristic coefficients are called affinity laws. Using characteristic pump parameters such as the impeller diameter (D), rotational speed (n ), acceleration due to gravity (g) and the density of the fluid handled (ρ), various ...

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• ### Affinity Laws for Pumps and Fans - Vortarus

The affinity law calculations assume that each pump operates at the same efficiency and that the pumped fluid does not change (constant density). Affinity Law Terminology. Before we cover the laws, we'll define the following terms: N is shaft rotational speed. D is impeller diameter.

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• ### Basic Pump Parameters and the Affinity Laws

2020-4-10 · efficiency, and (3) drive efficiency. The overall pump operational efficiency (4) is the product of the three preceding efficiencies. A complete discussion of hydraulic efficiency will be provided when the subject of power is undertaken. In the context of this course, efficiency means hydraulic efficiency and it will be denoted with the symbol E.

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• ### Pump Affinity Laws and Energy Savings | Pool Side

2021-5-3 · And according to Affinity laws, when you reduce the pump speed in half, you cut consumption by 87%. Besides cutting back your energy bill, using an energy-efficient pool pump is crucial for supporting the environment and there are currently available rebates on select variable speed pumps !

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• ### PUMP AFFINITY LAWS MODIFIED TO INCLUDE VISCOSITY

2018-7-12 · The pump Affinity Laws have been modified to include the effects of viscosity. The results are simple 2D curves that represent the head-flow rate and efficiency-flow rate relationships for a specific pump. The new Modified Affinity Laws were

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• ### Cheat Sheets: The Affinity Laws - Empowering Pumps

2013-5-31 · Just last week, a staff engineer at a chemical plant wrote to me to inform me that his company had purchased the wrong pump for a boiler. The boiler needed a feedwater pump rated at 950 ft. @ 30 GPM. Through some error, they took delivery on a pump rated at 950 ft. @ 60 GPM. The pump was delivering twice the required flow to the boiler.

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• ### Affinity Laws - researchgate.net

Applying the affinity law, if speed of a motor driving a pump is reduced to 80% of its speed, the work needed to overcome friction is the cube of 80%, or 51.2% of the work needed at full speed.

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• ### Pump Affinity Laws - Made in Britain

This law is expressed with the following formula: P1/P2 = (N1/N2)3 or (D1/D2)3. Where P is equal to power, N is equal to shaft speed, and D is equal to impeller diameter. Use of the Affinity Laws The affinity laws will produce highly accurate results when …

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• ### Affinity Laws for Pumps and Fans - Vortarus

The affinity law calculations assume that each pump operates at the same efficiency and that the pumped fluid does not change (constant density). Affinity Law Terminology. Before we cover the laws, we'll define the following terms: N is shaft rotational speed. D is impeller diameter.

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• ### Pump affinity laws | KSB

The affinity laws for centrifugal pumps state that the H/Q curves at various rotational speeds can be derived from the following relationship as conventionally represented:. Q Flow rate H Head Y Specific energy n Rotational speed. If P Q = ρ · g · Q · H (see Pump power output) and P = PQ η (see Pump power input), and assuming a constant density (ρ) of the fluid handled and a …

Get Price
• ### Pump Affinity Law Calculator - Pipeng Toolbox

Pump Affinity Or Similarity Law Calculation Module . ... Pump efficiency scaling should be combined with flowrate scaling. Pump efficiency varies with flowrate. A known pump can be scaled to operate at the best efficiency point (BEP) with a required design flow rate and delta pressure using the affinity laws. The pump curve is calculated using ...

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• ### - Affinity Laws - Beckwith & Kuffel

2021-5-15 · The affinity laws express the mathematical relationship between the several variables involved in pump performance. They apply to all types of centrifugal and axial flow pumps. They are as follows: With impeller diameter D held constant: Where: Q = Capacity, GPM. H = Total Head, Feet. BHP = Brake Horsepower. N = Pump Speed, RPM. With speed N ...

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• ### What is The Affinity Law - Pump Law - Definition

2019-5-22 · The Affinity Laws – Pump Laws. The centrifugal pump is a very capable and flexible machine. It is not necessary to design specific pump for each specific system. The performance of centrifugal pump can be changed by the change in impeller diameter or its rotational speed. The affinity laws, or the pump laws, state how such changes influence the performance of the pump.

Get Price
• ### Basic Pump Parameters and the Affinity Laws

2020-4-10 · efficiency, and (3) drive efficiency. The overall pump operational efficiency (4) is the product of the three preceding efficiencies. A complete discussion of hydraulic efficiency will be provided when the subject of power is undertaken. In the context of this course, efficiency means hydraulic efficiency and it will be denoted with the symbol E.

Get Price
• ### The Affinity Laws - Pump Laws - Centrifugal Pumps

2021-5-10 · The Affinity Laws – Pump Laws. The centrifugal pump is a very capable and flexible machine. It is not necessary to design specific pump for each specific system. The performance of centrifugal pump can be changed by the change in impeller diameter or its rotational speed. The affinity laws, or the pump laws, state how such changes influence the performance of the pump.

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• ### Affinity Laws | Pump Corrosion & Technology

Many pumping applications require a pump to be operated at speeds that are different from the published performance curves. The affinity laws are mathematical relationships that allow the performance of a pump to be determined at these different speeds. The affinity laws are applied to a specific point on a performance curve.

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• ### Affinity Law - Pump engineering - Eng-Tips

2017-11-4 · I now have the understanding of affinity law, that it applies to centrifugal pumps & fans, but not to PD pumps. We are improving the efficiency of our tanks (5 units) cleaning (with different volume) via single PD pump by varying the speed with VFD, and the variables are flow rate and power (kW). While the parameter we want constant is Pressure.

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• ### What is The Affinity Law - Pump Law - Definition

2019-5-22 · The Affinity Laws – Pump Laws. The centrifugal pump is a very capable and flexible machine. It is not necessary to design specific pump for each specific system. The performance of centrifugal pump can be changed by the change in impeller diameter or its rotational speed. The affinity laws, or the pump laws, state how such changes influence the performance of the pump.

Get Price
• ### The Affinity Laws - Pump Laws - Centrifugal Pumps

2021-5-10 · The Affinity Laws – Pump Laws. The centrifugal pump is a very capable and flexible machine. It is not necessary to design specific pump for each specific system. The performance of centrifugal pump can be changed by the change in impeller diameter or its rotational speed. The affinity laws, or the pump laws, state how such changes influence the performance of the pump.

Get Price
• ### Affinity Law and Efficiency of a Pump Curve | Physics

2019-4-30 · Homework Statement (Pump Curve given as attachment) [/B] Find the point where the pump is delivering 1,200 gpm at 45 ft of head. I. What is the pump efficiency (read from the pump curve data)? ii. What is the hp delivered to the water? iii. What is the shaft hp required to drive the pump...

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• ### Evaluating the Approximation of the Affinity Laws and ...

The affinity laws, however, contain approximations because they do not take into account factors that do not scale with velocity. In particular, the approximation inherent in the affinity law that computes power and efficiency can produce a misleading result, especially for small-size pumps.

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• ### Peerless Pump Company Indianapolis IN, 46207-7026 ...

2006-1-23 · Peerless Pump Company Indianapolis IN, 46207-7026 TECHNICAL INFORMATION Bulletin NUMBER FOURTEEN THE AFFINITY LAWS & SPECIFIC SPEED IN CENTRIFUGAL PUMPS By R.P. Horwitz Project Engineer AFFINITY LAWS The performance of a given pump at various speeds and the performance of geometrically similar pumps is governed by a set of …

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• ### Pump Basics - INSCO Group

2015-1-8 · THE GOOD NEWS - Affinity law theory helps us understand the principle of flow, head, and power dynamics. In practical application, Grundfos provides all the information you need to easily determine your energy savings with E-Pumps and BoosterpaQs. All you need to know is the system head and flow requirements to determine the right pump for the job.

Get Price
• ### Affinity Law - Pump engineering - Eng-Tips

2017-11-4 · I now have the understanding of affinity law, that it applies to centrifugal pumps & fans, but not to PD pumps. We are improving the efficiency of our tanks (5 units) cleaning (with different volume) via single PD pump by varying the speed with VFD, and the variables are flow rate and power (kW). While the parameter we want constant is Pressure.

Get Price
• ### Centrifugal Pump Minute | Griswold

In this Centrifugal Pump Minute, James Farley, Griswold Product Manager, discusses the Affinity Law formula that can be used to predict pump performance when changing speeds. Using the Griswold test lab, James provides a real-world example of the accuracy of the Affinity Law.

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• ### BEWARE THE AFFINITY POLICE - Bachus Inc

2006-6-20 · The second affinity law is more interesting. Head changes by the square of the speed change. In this case, head means all pump heads, including the shut-off head, best efficiency head, net positive suction head, friction head, discharge pressure, seal chamber pressure and all elevation changes. A pump previously generating 100 psi

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• ### Fan Affinity Laws - Engineering ToolBox

2021-5-7 · The Affinity Laws for centrifugal pumps and fans are used to express the influence on volume capacity, head (pressure) and/or power consumption due to. change in wheel speed - revolutions per minute (rpm), and/or; geometrically similarity by change in impeller diameter; Note that the affinity laws for pumps are not identical with fans.. Fan Affinity Laws ...

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• ### Affinity Law and Efficiency of a Pump Curve | Physics

2019-4-30 · Homework Statement (Pump Curve given as attachment) [/B] Find the point where the pump is delivering 1,200 gpm at 45 ft of head. I. What is the pump efficiency (read from the pump curve data)? ii. What is the hp delivered to the water? iii. What is the shaft hp required to drive the pump...

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• ### Affinity Laws for Pumping Systems (ALPS) - Part One ...

2011-12-17 · At speeds higher and lower than 3400-rpm, the 'affinity law' curve and pumping system curve diverge from one another.) I want to stress that there is nothing wrong with using the affinity laws. They are perfectly capable of helping you create modified pump curves at different speeds and impeller diameters.

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• ### Pump Affinity Laws by CENTRIFUGALPUMP.COM and

2019-8-15 · Pump Affinity Laws are equations of proportionality that indicate how a change in impeller diameter [D], or rotative speed [N], affects the capacity [Q], the differential head [H], and the required brake horsepower [HP] of a centrifugal pump. Affinity Laws are also known as Affinity Equations. According to Affinity Laws:

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• ### 6 Centrifugal Pump Affinity Laws and Performance

Centrifugal Pump Performance Curves • Pump Performance Curves – A pump’s capacity I.e. flow rate is plotted against its developed head – Also shows its efficiency (BEP), required input power, NPSHr, speed (RPMs), and other information such as pump size and type, impeller size, etc. – Generated by tests performed by the manufacturer ...

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• ### Pump Basics - INSCO Group

2015-1-8 · THE GOOD NEWS - Affinity law theory helps us understand the principle of flow, head, and power dynamics. In practical application, Grundfos provides all the information you need to easily determine your energy savings with E-Pumps and BoosterpaQs. All you need to know is the system head and flow requirements to determine the right pump for the job.

Get Price
• ### M4A1 Affinity Law Model.docx - M4A1 Affinity Law

M4A1: Affinity Law Model Affinity law’s for pumps are use to express the relationship between flow rate (m), pressure (P), power (Hp), speed(N), and impeller diameter. That is, for a given speed or impeller diameter the flow rate, pressure, and power of the pump can be calculated using these laws: ´ m 2 = ´ m 1 (N 2 N 1) P 2 = P 1 (N 2 N 1) 2 Hp 2 = Hp 1 (N 2 N 1) 3 Only …

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• ### BEWARE THE AFFINITY POLICE - Bachus Inc

2006-6-20 · The second affinity law is more interesting. Head changes by the square of the speed change. In this case, head means all pump heads, including the shut-off head, best efficiency head, net positive suction head, friction head, discharge pressure, seal chamber pressure and all elevation changes. A pump previously generating 100 psi

Get Price
• ### Multi-stage pumps can deliver efficiency gains

The Affinity Laws show how a pump’s performance changes with changing pump speed (RPM). When a pump has a flat curve as shown in Figure 2, a relatively small change in pressure produces a large change in flow, making control via pressure difficult, and limiting the amount of speed reduction available.

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• ### Centrifugal Pump Minute | Griswold

In this Centrifugal Pump Minute, James Farley, Griswold Product Manager, discusses the Affinity Law formula that can be used to predict pump performance when changing speeds. Using the Griswold test lab, James provides a real-world example of the accuracy of the Affinity Law.

Get Price
• ### Energy Tips – Pumping Systems

2014-5-22 · with the system curve can help you calculate pump shaft horsepower requirements at each flow-rate point. (Affinity laws are valid for circulating water pumping applications or fluid transfer applications with little static head.) Factor in motor and drive efficiency at each operating point to calculate weighted input power (see Table 3).

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