Advanced Pump Fundamentals Agenda 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.) 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 Disadvantages Can’t Run Dry Length of Pump Advantages 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

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 Self-Priming/Suction Lift Ability to Vary Capacity Non-Pulsating Flow Run Dry for a Short Time High Temperature Disadvantages Pressure Solids Abrasion High Shear 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 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 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 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 Discharge 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

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:__________________.