Advanced Pump Fundamentals
Agenda
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Introduction
Centrifugal and PD Pump Basic Fundamentals
Pump Construction Fundamentals
Bearing and Bearing Reliability
Pump Performance Curves
System Curves
Changing Pump Conditions
Pump Affinity Laws
Advanced Pump Fundamentals
Agenda (contd.)
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Parallel and Series Pump Operations
Fixed and Variable Speed Operations
Maintenance Checks
Why do pumps fail?
Troubleshooting Pumps
Final Exam and Course Critique
Centrifugal and PD Pumps Basics
Kinetic Pump Tree
Classification of Pumps
• Centrifugal or Kinetic Pumps
–Pressure creating device
–Converts velocity energy (Kinetic
Energy) to Pressure Energy (Flow
Work)
–Flow depends upon system
characteristics
Classifications of Pumps
• Positive Displacement Pumps
– Flow creating device
– Fixed volume of fluid delivered per
rotation
– Pressure developed dependent upon
system characteristics
PUMP TYPES
• CENTRIFUGAL OR KINETIC PUMPS
– VOLUTE PUMPS
• MIXED FLOW
• AXIAL FLOW
• RADIAL FLOW
PUMP TYPES
• CENTRIFUGAL OR KINETIC PUMPS
– DIFFUSER PUMPS
• VERTICAL TURBINE
• HORIZONTAL
PUMP TYPES
• CONCENTRIC VOLUTE PUMPS
– REGENERATED TURBINE
– HIGH SPEED
– RADIAL VANE
– RECESSED IMPELLER
PUMP TYPES
• POSITIVE DISPLACEMENT PUMPS
– RECIPROCATING PUMPS
• PLUNGER
• PISTON
• DIAPHRAGM
PUMP TYPES
• POSITIVE DISPLACEMENT PUMPS
– ROTARY PUMPS
• PROGRESSING CAVITY
• SLIDE VANE
• LOBE
• GEAR
• SCREW
• PERISTALTIC
http://www.coleparmer.com/techinfo/techinfo.asp?htmlfile=SelectingLiqPumps.htm
Positive Displacement Pump:
Progressing Cavity
Positive Displacement Pump:
Progressing Cavity
• Advantages
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Self-Priming/Suction Lift
Ability to Vary Capacity
Non-Pulsating Flow
Pressure
Solids Laden Fluids
Abrasive Fluids
Handles High Viscosity
Applications
Handles Shear Sensitive Fluids
Runs in Either Direction
Accurate Repeatable Flow
Open Throat
• Disadvantages
•Can’t Run Dry
•Length of Pump
Positive Displacement Pump: Vane
•Advantages:
•Self-Priming/Suction Lift
•Ability to Vary Capacity
•Run Dry Short Time
•Handles High Viscosities
•Handles Abrasive Fluids
•Handles Shear Sensitive Fluids
•Self Adjusting Vanes - For Performance
•Disadvantages:
•Solids
•Pressure Capabilities
•Material Limitations
Positive Displacement Pump: Lobe or Cam
•Advantages:
•Self-Priming/Suction Lift
•Ability to Vary Capacity
•Run in Either Direction
•Handles High Viscosities
•Accurate Repeatable Flow
•Run Dry for a Short Time
•Disadvantages:
•Abrasion Resistance
•Pressure Capabilities
•Stuffing Box
•Jamming
•Pump Efficiency
•Non-Pulsating Flow
Positive Displacement Pump: Gear
•Advantages
•Disadvantages
•Self-Priming/Suction Lift
•Pressure
•Ability to Vary Capacity
•Solids
•Non-Pulsating Flow
•Abrasion
•Run Dry for a Short Time
•High Shear
•High Temperature
•Viscosity
Positive Displacement Pump: Screw
Peristaltic Pumps
• Positive displacement type
• Pulse-type
•Advantages
•Self-Priming/Suction Lift
•Ability to Vary Capacity
•Handles “Difficult” Fluids
•Reversible
•Can Run Dry
•No Seals
•Disadvantages
•Pressure
•Abrasion
•Temperatures
•Short Hose Life
•Pulsation
•Drive Options
•High HP Requirement
http://www.animatedsoftware.com/pumpglos/peristal.htm
Diaphragm Pump Component Locations
How It Works
Air Diaphragm Pumps
• Advantages
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– Self-Priming/Suction Lift
– Ability to Vary Capacity
– Handles Abrasive and
Suspended solids
– Handles Viscous Fluids
– Run Dry
– Length of Pump
– No Seals or Packing
– Closes Discharge
– Submersible
– No Efficiency Loss Due to Wear
Disadvantages
– Pressure
– Noise
– Pulsation
– Icing
– Power Consumption
Short Quiz
• Name at least three positive displacement
pumps:__________, __________, _________.
• What are the three types of centrifugal
pumps? __________, _________, _________.
CENTRIFUGAL PUMP THEORY
Kinetic (Dynamic) Pumps
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Used for low-pressure, high flow rate applications
Little use in fluid power
Used to transfer fluids
Three main types:
– Centrifugal
– Axial
– Mixed flow
CENTRIFUGAL PUMP
THEORY
- Centrifugal pumps add pressure (energy) to a liquid by
increasing the liquid’s velocity through centrifugal force
- Liquid is drawn into pump through suction nozzle, A,
the impeller eye, B, is the lowest pressure point in the
pump. As fluid enters the eye it is moved towards the
pump perimeter by centrifugal force. The fluid is picked
up by the impeller vanes, C, and accelerated in the
direction of rotation. As fluid leaves the impeller its
velocity approaches that of the impeller vane tip.
CENTRIFUGAL PUMP
THEORY
- The casing, D, is expanding volute design. As
liquid moves from the impeller to the pump
case, the velocity energy is converted to
pressure energy. As the high pressure liquid
approaches the discharge nozzle, E, it is
directed through the discharge by the cutwater.
Kinetic Pumps: Centrifugal
Kinetic Pumps: Axial
Kinetic Pumps: Mixed Flow
Short Quiz
• What are the two physical components
mainly responsible for converting kinetic
(velocity) energy into pressure energy in a
centrifugal pump? __________, __________.
PRESSURE
• Force exerted per unit area
– Pressure:
P
Force F

Area
A
• When applied to a fluid, the pressure is
transmitted undiminished in all directions
• Usually expressed in pounds per square inch
(psi), or kiloNewton per square meter (kPa).
Atmospheric Pressure
• The force exerted on a unit area by the weight
of the atmosphere
• Atmospheric pressure at sea level is 14.7 psi,
at 60 °F
• Also expressed as 29.9 inches of mercury (Hg),
and 34 feet of water.
Gauge Pressure - PSIG
• The difference between a given pressure and
that of the atmosphere
– Absolute = Gage + Atmospheric*
– psia = psig + 14.7 psia
– *14.7 psia at sea level
Pressure Scale
Vacuum
• Pressure below atmospheric
• Usually expressed in inches of mercury, in Hg
Short Quiz
• Define gage pressure:__________________.
• True or False: Vacuum pressure is greater than
atmospheric pressure:__________________.
Pump Pressures
• Suction Pressure
– The actual pressure, positive or negative at the
pump suction nozzle as measured by a pressure
gauge
• Discharge Pressure
– The actual pressure at the pump discharge nozzle as
measured by a pressure gauge
– Equal to pump suction pressure plus the total
developed head of the pump (PD = PS + DP; where
DP = hA*g; hA  pump head)
Pump Pressures
• Stuffing Box Pressure:
– The pressure acting on the stuffing box which
must be sealed
– Function of pump impeller design and the
presence or condition of wear rings
Pump Pressures
Impeller Design and Stuffing Box
Pressure
• Open impeller with back pump out vanes
– Stuffing box pressure = suction + 25% developed*
– Enclosed impeller with balanced holes
• Stuffing box pressure = suction + 10% developed *
– Double suction impellers
• Stuffing box pressure = suction pressure
* Developed pressure = Discharge-Suction (Pressure)
Note: These equations are approximations, and are effected
by the physical conditions of the pump
Short Quiz
• Define stuffing box pressure:_____________.
• True or False: Suction pressure is always
greater than discharge pressure:___________.
Specific Gravity
• Ratio of a liquids density to that of water at
sea level, 60° F and 14.7 PSIA
– Water has a specific gravity of 1.0
• SG = r/rwater; r= density
– Specific gravity of a liquid affects pressure
relative to its height
• DP (pressure at low point – pressure at high point) = g*h
• r r*g; h=fluid height
– Specific gravity affects pump horsepower
requirements in direct relation to pressure and
capacity
• Denser fluids require greater pump horsepower
Pressure-Elevation Relationship
• Valid for homogeneous fluids at rest (static)
P2 = Patm + rgh
Free Surface
Free Surface
P2
P1
P1 > P2
Specific Gravity
PSI  2.31
Head _ in _ feet 
SG
Head _ in _ feet  SG
P( PSI ) 
2.31
Short Quiz
• If the density of water is 1,000 kg/m3 and
cooking oil’s is 800 kg/m3, find/determine:
– a) Specific gravity of cooking oil:______________.
– b) Will water be on top of cooking oil, or the other
way around? Why?________________________.
• True or False: Specific gravity has no impact on
pump horsepower:__________________.