Centrifugal Pump Basics Terms commonly used in the pumping industry

Centrifugal Pump Basics zCentrifugal, (Sen-trif’-u-gal) zTending to fly from a center zThrown from a center zCentrifugal pump impeller does just that zWater drawn into impeller eye, accelerated down the blades and thrown against pump casing that directs flow out of discharge

Centrifugal Pump Basics Centrifugal Pump Liquid into impeller eye from pump suction Impeller Rotation

Centrifugal Pump Basics Centrifugal Pump Curve

Centrifugal Pump Basics Centrifugal Pump Curve

Centrifugal Pump Basics z1 Gallon of water 60DegF) weighs 8.33 lbs z1 cubic foot of water contains 7.48 gallons zSpecific Gravity (Sp Gr) of a fluid is the relationship of the density (lbs/ft3) to that of water (62.3 lbs/ft3) WATER COLUMN 1 psig 2.31 ft 1”1” 1”1” Basic Fluid Facts

Centrifugal Pump Basics WATER 1.0 sp gr GASOLINE 0.8 sp gr BRINE 1.2 sp gr hp = gpm*hd*sp gr* *Pump Eff Pump head (ft) = psig*2.31 sp gr 231 ft 120 psig80 psig100 psig Pump Shut-off Head 231ft Specific Gravity

Centrifugal Pump Basics 1 inch square column of air, the height of the earth’s atmosphere (From Sea Level) weights 14.7 lbs Air Column 14.7 psia 0 psig 1”1” 1”1” BASIC FLUID FACTS

Centrifugal Pump Basics Basic Centrifugal Pump Equations For variations in impeller diameter, at constant speed: D1 = Q1 = H1BHP1 = D1 3 D2 Q2 H2BHP2 D2 3 For variations in speed, with constant impeller diameter: S1 = Q1 = H1BHP1 = S1 3 S2 = Q2 H2BHP2 S2 3 Where:D = Impeller Diameter (Ins / mm) H = Pump Head (Ft / m) Q = Pump Capacity (gpm / lps) S = Speed (rpm / rps) BHP = Brake Horsepower (Shaft Power - hp / kW)  

Centrifugal Pump Basics Friction Loss for Water in Commercial Steel Pipe (Schedule 40) System Resistance

Centrifugal Pump Basics zA “Closed” hydronic system is one that has only one interface with air or flexible membrane zAn “Open” hydronic system is one that has more than one interface with air or a flexible membrane Open & Closed Systems

Centrifugal Pump Basics LOAD SOURCE EXPANSION BUILDING HEIGHT Balancing Valve 3-Way Control Valve Isolating Valve LOAD “Closed” System

Centrifugal Pump Basics System Resistance Curve CAPACITY Friction Losses “Closed” System Resistance Curve

Centrifugal Pump Basics Static Suction Head CONDENSER Static Head “Open” System

Centrifugal Pump Basics HEAD System Head Curve CAPACITY Friction Losses Total Static Head “Open” System Resistance Curve

Centrifugal Pump Basics LOAD SOURCE EXPANSION BUILDING HEIGHT BALANCING VALVE 2 WAY CONTROL VALVE ISOLATING VALVE LOAD “Closed” System with Minimum Maintained Pressure

Centrifugal Pump Basics HEAD System Head Curve CAPACITY Friction Losses Minimum Maintained Pressure “Closed” System Resistance Curve with Minimum Maintained Pressure

Centrifugal Pump Basics Terms commonly used in the pumping industry