1. System One Pumps S1-200 Centrifugal Hydraulics
Hydraulic Facts
Pump Operations
Advanced

2. System One Pumps
Hydraulic Facts

3. Absolute and Gage Pressure Atmospheric Pressure at Sea Level
SYSTEM ONE PUMPS
Absolute and Gage Pressure
Absolute Pressure
Gauge Pressure
14.7 psia
Atmospheric Pressure at Sea Level
0 psig
0 barg
1.01 bara
0“ of Hg Vacuum
30" of Hg Vacuum
0 psia
0 bara

4. SYSTEM ONE PUMPS
Weight of Water
2.31 Ft.
1 psi

5. SYSTEM ONE PUMPS
Weight of Water
10.2 m
1 bar

6. SYSTEM ONE PUMPS
Weight of Water
One Cubic Foot of Water
.433 psi

7. One Cubic Meter of Water
SYSTEM ONE PUMPS
Weight of Water
One Cubic Meter of Water
.098 bar

8. SYSTEM ONE PUMPS Specific Gravity
Specific gravity is the density of a liquid as compared to water at a give temperature.
Water is used as the standard at 14.7 psia (1.01 bar) at 60ºF (15.6°C).
Its specific gravity is 1.0 at this standard temperature.
Because it is a ratio of the same properties it has no units.
Water 1.0 spg
Caustic 1.5 spg
Caustic 1.5 spg
100 Ft.
30.5 m
Gasoline .85 spg
36.7 psi
2.53 bar
43.3 psi
2.99 bar
65 psi
4.48 bar

9. SYSTEM ONE PUMPS Vapor Pressure (PSIA)
Every fluid has its own unique vapor pressure curve where the vapor pressure is plotted in relation to temperature.
As temperature increases, the vapor pressure increases. This means that as a fluid’s temperature increases, it requires more pressure to keep it from boiling and remain liquid.

10. SYSTEM ONE PUMPS Viscosity
Viscosity is the measure of a fluid’s resistance to flow under an applied force at a given temperature.
Viscosity can be thought of as the “Thickness” of a fluid as it moves due to this force.

11. System One Pumps
Pump Operation

12. Centrifugal Pump Curve
SYSTEM ONE PUMPS
Centrifugal Pump Curve

13. Velocity / Pressure /Head
SYSTEM ONE PUMPS
Velocity / Pressure /Head
Head is a pump term often used to describe the mechanical energy added to the fluid by centrifugal force. Centrifugal pumps are constant energy devices. This means that for a given pump operating at a certain speed and handling a definite fluid volume, the energy transferred to the fluid (foot-lbs. per foot) is the same for any fluid regardless of density.
High Velocity Low Pressure
Low Velocity High Pressure
100 Ft.
30.5 m
Rotation

14. Suction Pressure (P1/ PSIG or barg)
SYSTEM ONE PUMPS
Suction Pressure (P1/ PSIG or barg) P1

15. Discharge Pressure (P2/ PSIG or barg)
SYSTEM ONE PUMPS
Discharge Pressure (P2/ PSIG or barg) P2

16. Differential Pressure (PSIG or barg)
SYSTEM ONE PUMPS
Differential Pressure (PSIG or barg)
∆ P = P2 – P1 P2 P1

17. SYSTEM ONE PUMPS Head and Pressure
Head (ft.) x Sp. Gr Diff. Pressure (psi) x 2.31
Diff. PSI = Head (ft.) =
Sp. Gr.
One psi of pressure equals 2.31 ft. of water and 2.31 ft. of water equals 1 psi of pressure
Absolute pressure (PSIA) = atmospheric pressure + gauge pressure
Gauge pressure (PSIG) = the gauge reading and does not include atmospheric pressure
Differential pressure (Diff. P) = the difference between discharge pressure and suction pressure
Total Dynamic Head (TDH) = Diff. h static + Diff. h pres + h friction + h velocity

18. SYSTEM ONE PUMPS Head and Pressure
Head (m) x Sp. Gr Diff. Pressure (bar) x 10.2
Diff. bar = Head (m) =
Sp. Gr.
One bar of pressure equals 10.2 m of water.
10.2 m of water equals 1 bar of pressure .
Absolute pressure (barA) = atmospheric pressure + gauge pressure
Gauge pressure (barG) = the gauge reading and does not include atmospheric pressure
Differential pressure (Diff. P) = the difference between discharge pressure and suction pressure
Total Dynamic Head (TDH) = Diff. h static + Diff. h pres + h friction + h velocity

19. SYSTEM ONE PUMPS Specific Gravity
Specific gravity is the density of a liquid as compared to water at a give temperature.
Water is used as the standard at 14.7 psia (1.01 bar) at 60ºF (15.6°C).
Its specific gravity is 1.0 at this standard temperature.
Because it is a ratio of the same properties it has no units.
Water 1.0 spg
Caustic 1.5 spg
Caustic 1.5 spg
100 Ft.
30.5 m
Gasoline .85 spg
36.7 psi
2.53 bar
43.3 psi
2.99 bar
65 psi
4.48 bar

20. Differential Head (ft. or m)
SYSTEM ONE PUMPS
Differential Head (ft. or m)
If P1 = 50 psig, P2 = 150 psig, SPG. = 1, Diff. Head = ?
If P1 = 50 psig, P2 = 150psig, SPG. = .5, Diff. Head = ?
If P1 = 50 psig, P2 = 150psig, SPG. = 2, Diff. Head = ?
If P1 = 3 barg, P2 = 9 barg, SPG. = 1, Diff. Head = ?
If P1 = 3 barg, P2 = 9 barg, SPG. = .5, Diff. Head = ?
If P1 = 3 barg, P2 = 9 barg, SPG. = 2, Diff. Head = ?

21. Differential Head (ft.)
SYSTEM ONE PUMPS
Differential Head (ft.)
If P1 = 50psig, P2 = 150 psig, SPG. = 1, Diff. Head = 231 ft.
If P1 = 50psig, P2 = 150psig, SPG. = .5, Diff. Head = 462 ft.
If P1 = 50psig, P2 = 150psig, SPG. = 2, Diff. Head = 116 ft.
Diff. Pressure x 2.31
Diff. Head =
SPG
(150 – 50 ) x 2.31
Diff. Head = = 462 ft. .5

22. SYSTEM ONE PUMPS Differential Head (m)
If P1 = 3 barg, P2 = 9 barg, SPG. = 1, Diff. Head = 61.2 m
If P1 = 3 barg, P2 = 9 barg, SPG. = .5, Diff. Head = m
If P1 = 3 barg, P2 = 9 barg, SPG. = 2, Diff. Head = 30.6 m
Diff. Pressure x 10.2
Diff. Head =
SPG
( 9-3 ) x 10.2
Diff. Head = = m .5

23. Differential Pressure (psi or bar)
SYSTEM ONE PUMPS
Differential Pressure (psi or bar)
If a pump is designed for 231 ft. of Differential Head.
And P1 = 50psig, SPG. = 1, Diff. P = ?
And P1 = 50psig, SPG. = .5, Diff. P = ?
And P1 = 50psig, SPG. = 2, Diff. P = ?
If a pump is designed for 61.2 m of Differential Head.
And P1 = 3 barg, SPG. = 1, Diff. P = ?
And P1 = 3 barg, SPG. = .5, Diff. P = ?
And P1 = 3 barg, SPG. = 2, Diff. P = ?

24. Differential Pressure (psi)
SYSTEM ONE PUMPS
Differential Pressure (psi)
If a pump is designed for 231 ft. of Differential Head.
And P1 = 50psig, SPG. = 1, Diff. P = 100 psig
And P1 = 50psig, SPG. = .5, Diff. P = 50 psig
And P1 = 50psig, SPG. = 2, Diff. P = 200 psig
Diff. Head x SPG.
Diff. Pressure =
2.31
231 x .5
Diff. Pressure = = 50 psig

25. Differential Pressure (bar)
SYSTEM ONE PUMPS
Differential Pressure (bar)
If a pump is designed for 61.2 m of Differential Head.
And P1 = 3 barg, SPG. = 1, Diff. P = 6 barg
And P1 = 3 barg, SPG. = .5, Diff. P = 3 barg
And P1 = 3 barg, SPG. = 2, Diff. P = 12 barg
Diff. Head x SPG.
Diff. Pressure =
10.2
61.2 x .5
Diff. Pressure = = 3 barg

26. SYSTEM ONE PUMPS Brake Horsepower (BHP) Head (ft.) x Sp. Gr. x GPM
3960 x Pump efficiency
@ 460 V, BHP = Amps x ,
@230 V, BHP = Amps x
Head (m) x Sp. Gr. x m³/hr
BKW =
367 x Pump efficiency

27. Brake Horsepower (BHP)
SYSTEM ONE PUMPS
Brake Horsepower (BHP)
If Diff. Head = 231 ft., SPG. = 1, Q = 100 gpm, Eff. = 50%,
BHP = ?
If Diff. Head = 231 ft., SPG. = 2, Q = 100 gpm, Eff. = 50%,
BHP = ?

28. SYSTEM ONE PUMPS Brake Horsepower (BHP) Head (ft.) x Sp. Gr. x GPM
3960 x Pump efficiency
231 x 1 x 100
BHP = = 11.66
3960 x .50
231 x 2 x 100
BHP = = 23.34
3960 x .50

29. Net Positive Suction Head (NPSH)
SYSTEM ONE PUMPS
Net Positive Suction Head (NPSH)
NPSH available equals h static + h pressure − h friction − h vapor pressure
NPSH required Is the point at which a centrifugal pump starts to cavitate (3% head drop). These values are shown on the individual pump curve.
It is recommended that NPSHa is greater than NPSHr by 3 ft (1 m)
NPSH is always calculated in PSIA (BARA).
Open system “Flooded Suction”
Closed System “liquid at boiling point”
Total Static Head
Discharge Static Head
Suction Static Head

30. Net Positive Suction Head (NPSH)
SYSTEM ONE PUMPS
Net Positive Suction Head (NPSH)
NPSH available equals h static + h pressure − h friction − h vapor pressure
14.7 PSIA
NPSHA =
10 ft. H Static head
+ 34 ft. H pressure (14.7 x 2.31)
– 0.5 ft. H friction (line loses)
– 1.2 ft. H vapor pressure
= ft.
Water at 80 deg. F
Liquid Level
10 ft.

31. SYSTEM ONE PUMPS Net Positive Suction Head (NPSH) Closed System
NPSH available = h static + h pressure − h friction − h vapor pressure
25.3 psig
NPSHA =
10 ft. H static
+ 40 psia H pressure
(25.3 psig psia)
– 1 ft. H friction
– 40 psia H vapor pressure
= 9 ft.
Methyl Alcohol at 200ºF
Vapor Pressure 40 psia
Liquid Level
10 ft.

32. SYSTEM ONE PUMPS Pressure Profile E D C Increasing Pressure
Inlet Piping Losses
Friction
Impeller Turbulence
Impeller Pressure E D C
Increasing Pressure
Dropping Pressure B A
A B C D E
Liquid Path
Vaporization Point

33. SYSTEM ONE PUMPS Pump Cavitation Rotation Increasing pressure
Vapor bubble
Impeller surface
Cavitation damage

34. SYSTEM ONE PUMPS
Suction Piping
L (min.) = 10 x D in. D L

35. SYSTEM ONE PUMPS Affinity Laws
Affinity laws predict the pump performance changes due to speed or impeller diameter changes.
Q = capacity, N = rpm, BHP = horsepower, D = impeller diameter
Q2 = Q1 ( N2 / N1 ) Q2 = Q1 ( D2 / D1 )
H2 = H1 ( N2/ N1 ) H2 = H1 ( D2 / D1 )2
BHP2 = BHP1 ( N2 / N1 ) BHP2 = BHP1 (D2 / D1)3

36. Effects Caused by Viscosity
SYSTEM ONE PUMPS
Effects Caused by Viscosity
BHP Higher
Head Lower
Efficiency Lower

37. System One pumps
Advanced

38. ( lbs. / min. ) x Specific Heat
SYSTEM ONE PUMPS
Pump Temperature Rise
Temperature rise is power being converted to heat. The heat goes to the directly into the fluid.
(BHP – WHP) x 42.41
Temperature rise deg. F =
( lbs. / min. ) x Specific Heat
BHP= brake horse power, WHP=horse power at 100% eff., 42.41= conversion of hp to Btu./ min., lbs./ min = gpm x 8.33 x sp. gr.

39. SYSTEM ONE PUMPS Shaft Stiffness Ratio L3/D4 L3/D4
Higher equals increased vibration and decreased seal life
L3/D4
L is the distance from the impeller centerline to the centerline of the first bearing (usually radial bearing) in inches.
D is the smallest diameter of this shaft in inches.
The number should be as small as possible.

40. Impeller Radial Force At Any Flow
SYSTEM ONE PUMPS
F lbs.
Impeller Radial Force At Any Flow
F = K x H x S x D x B
2.31 D
K = THRUST FACTOR
H = HEAD (ft.)
S = SPECIFIC GRAVITY
D= IMPELLER DIAMETER (in.)
B = IMPELLER WIDTH (in.) B

41. SYSTEM ONE PUMPS
RADIAL LOAD Operation of a pump away from the BEP results in higher radial loads creating vibration and shaft deflection

42. RADIAL FORCES ON IMPELLER
SYSTEM ONE PUMPS
RADIAL FORCES ON IMPELLER
CUTWATER
SHUTOFF 0%
50%
100%
% CAPACITY of BEP
125%
150%
Length of Line = Force

43. SYSTEM ONE PUMPS Specific Speed and Suction Specific Speed
Specific speed ( Ns ) is an index number that determines the shape and physical proportions of an impeller.
Suction Specific Speed ( SSS ) is a rating number which indicates the relative ability to operate with low NPSHA. In general the SSS should be less than 12,500. Ideal would be 8,000.
RPM x ( GPM ) ½ RPM x ( GPM ) ½
Ns = SSS =
( HEAD max BEP)¾ ( NPSHR max BEP ) ¾
Ns Impeller Type
< Centrifugal / Radial
4000 to Mixed flow
> Axial Flow

44. System Head Calculations
SYSTEM ONE PUMPS
System Head Calculations
System Head Pipe
Velocity Head
H v = V 2 / 2g
V = Velocity of Liquid in Pipe
G= Gravitational Constant (32.2 ft/sec2 )
System Head Valves & Fittings
H f = K ( V 2 /2 g)

45. SYSTEM ONE PUMPS
System Curve
Design Point

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