Centrifugal Pump Basics Terms commonly used in Terms commonly used in the pumping industry the pumping industry
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Centrifugal Pump Basics
Terms commonly used in the Terms commonly used in the pumping industrypumping industry
Centrifugal Pump Basics
Centrifugal, (Sen-trif’-u-gal)
Tending to fly from a center
Thrown from a center
Centrifugal pump impeller does just that
Water 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 frompump suction
Impeller Rotation
Centrifugal Pump Basics
Centrifugal Pump Curve
Centrifugal Pump Basics
Centrifugal Pump Curve
Centrifugal Pump Basics
1 Gallon of water (U.S. @ 60DegF) weighs 8.33 lbs
1 cubic foot of water contains 7.48 gallons
Specific 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”
Basic Fluid Facts
Centrifugal Pump Basics
WATER1.0 sp gr
GASOLINE0.8 sp gr
BRINE1.2 sp gr
hp = gpm*hd*sp gr*100 3960*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”
BASIC FLUID FACTS
Centrifugal Pump Basics
Basic Centrifugal Pump EquationsFor variations in impeller diameter, at constant speed:
D1 = Q1 = H1 BHP1 = D13
D2 Q2 H2 BHP2 D23
For variations in speed, with constant impeller diameter:
S1 = Q1 = H1 BHP1 = S13
S2 = Q2 H2 BHP2 S23
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
A “Closed” hydronic system is one that has only one interface with air or flexible membrane
An “Open” hydronic system is one that has more than one interface with air or a flexible membrane
Open & Closed Systems
Centrifugal Pump Basics
LOAD
LOAD
LOAD
SOURCE
EXPANSION
BUILDINGHEIGHT
BalancingValve
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
HEA
D
System Head Curve
CAPACITY
Friction Losses
Total Static Head
“Open” System Resistance Curve
Centrifugal Pump Basics
LOAD
LOAD
LOAD
SOURCE
EXPANSION
BUILDINGHEIGHT
BALANCINGVALVE
2 WAY CONTROL VALVE
ISOLATINGVALVE
LOAD
“Closed” System with Minimum Maintained Pressure
Centrifugal Pump Basics
HEA
D
System Head Curve
CAPACITY
Friction Losses
MinimumMaintainedPressure
“Closed” System Resistance Curve with Minimum Maintained Pressure
Centrifugal Pump Basics
Terms commonly used in the Terms commonly used in the pumping industrypumping industry
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