Page 296 -

The Practical Pumping Handbook

16.2 Useful formulae
16.2.1 Head-pressure relationship

Head (in feet) x Specific Gravity
Pressure (in p.s.i.) =
2.31

Head (in meters) x Specific Gravity
Pressure (in Kg/Sq.Cm) =
10.2

16.2.2 Power calculation

USGPM x Head (in feet) x Specific Gravity
H.P. =
Efficiency x 3960
m3/hr, x Head (in meters) x Specific Gravity
kW =
Efficiency x 367.12

16.2.3 The affinity laws

Q2 = D2 or N2
Q1 D1 N1

~ ~

HP2 =/02/3 or IN2/3

HP, ~-~) ~NT)

16.2.4 Pressure in a static head system

Hs x s.g.
P
2.31

where P = Gauge pressure in pounds per square inch
Hs = Static Head of liquid in feet
s.g. = Specific Gravity of the liquid being pumped

! 268