PUMPS PUMPS Unit -IV Unit -IV CHE216: MOMENTUM CHE216: MOMENTUM TRANSFER TRANSFER
Nov 21, 2014
PUMPSPUMPSUnit -IVUnit -IV
CHE216: MOMENTUM CHE216: MOMENTUM TRANSFERTRANSFER
PRESENTATION OUTLINEPRESENTATION OUTLINE
Pump TerminologyPump Terminology Pump Classification:Pump Classification: - Reciprocating Pumps- Reciprocating Pumps - Rotary Pumps- Rotary Pumps - Centrifugal Pumps- Centrifugal Pumps Pumping ProblemsPumping Problems Power and Efficiency CalculationsPower and Efficiency Calculations Pump SelectionPump Selection
PUMP TERMINOLOGYPUMP TERMINOLOGY
PumpingPumping, , the addition of energy to athe addition of energy to a fluid fluid
Pumping action creates a partial vacuum while Pumping action creates a partial vacuum while atmospheric pressure forces liquid up.atmospheric pressure forces liquid up.
Pump performancePump performance, , specified in terms of Q and specified in terms of Q and HH::
)()
22()(/
22,,
sdsdgsgd ZZg
V
g
VPPtQH
DisplacementDisplacement,, the discharge of a fluid from a the discharge of a fluid from a vesselvessel
Centrifugal ForceCentrifugal Force,, used to produce kinetic used to produce kinetic energyenergy
PIST ON PUM PS
PLUNG ER PUM PS
DIAPHRAG M PUM PS
RE C IPRO C A T ING PUM PS
G EAR PUM PS
LOBE PUM PS
SCREW PUM PS
CAM PUM PS
VANE PUM PS
RO T A RY PUM PS
PO S IT IV E D IS PL A C E M E NT PUM PS C E NT RIF UG A L PUM PS
PUM PS
RECIPROCATING PUMPSRECIPROCATING PUMPS
Based on two stroke principleBased on two stroke principles:s:
√ √ High pressure, high efficiencyHigh pressure, high efficiency
√ √ Self-primingSelf-priming
XX Small quantity, vibration, physical dimension, Small quantity, vibration, physical dimension, uneven flowuneven flow
Used mainly for handling slurries inUsed mainly for handling slurries in plant processes plant processes and pipeline applicationsand pipeline applications
P IS TO N P U M P S
P L U N G E R P U M P S
D IA P H R A G M P U M P S
R E C IP R O C A TIN G P U M P S
P O S ITIV E D IS P L A C E M E N T P U M P S
Two valves and one stuffing boxTwo valves and one stuffing box AA rotating mechanism rotating mechanism for the for the
reciprocating pistonreciprocating piston UUses suction to raise ses suction to raise liquidliquid into into
the chamberthe chamber..
The principle of operation is same as that of the piston pump.The principle of operation is same as that of the piston pump. Two ball check valves on each sideTwo ball check valves on each side Low pressure on the upward part, high pressure on the downward Low pressure on the upward part, high pressure on the downward
partpart Used for high pressure applications and can discharge against a Used for high pressure applications and can discharge against a
pressure of 150 MPa or more.pressure of 150 MPa or more.
P IS TO N P U M P S
P L U N G E R P U M P S
D IA P H R A G M P U M P S
R E C IP R O C A TIN G P U M P S
P O S ITIV E D IS P L A C E M E N T P U M P S
For handling of corrosive liquids, toxic liquids, For handling of corrosive liquids, toxic liquids, suspensions of abrasive solids Diaphragm pumps suspensions of abrasive solids Diaphragm pumps are used.are used.
The pump is divided into two sections. In one The pump is divided into two sections. In one section of the pump, there is a liquid to be section of the pump, there is a liquid to be pumped and in other another section piston or pumped and in other another section piston or plunger working in oil, which actuates the plunger working in oil, which actuates the diaphragm.diaphragm.
RRod is od is mmoveoved tod to push push and pull and pull the diaphragm the diaphragm.. Can be used to make artificial hearts.Can be used to make artificial hearts.
P IS TO N P U M P S
P L U N G E R P U M P S
D IA P H R A G M P U M P S
R E C IP R O C A TIN G P U M P S
P O S ITIV E D IS P L A C E M E N T P U M P S
ROTARY PUMPSROTARY PUMPS Positive displacement typePositive displacement type
High pressure, high efficiencyHigh pressure, high efficiency
Liquids must be free of solidsLiquids must be free of solids
Handle viscous fluidsHandle viscous fluids Used mainly in, oil burners, soaps and Used mainly in, oil burners, soaps and
cosmetics, sugars, syrup, and molasses, cosmetics, sugars, syrup, and molasses, dyes, ink, bleaches, vegetable and dyes, ink, bleaches, vegetable and mineral oilsmineral oils
G E A R P U M P S
L O B E P U M P S
S C R E W P U M P S
C A M P U M P S
V A N E P U M P S
R O TA R Y P U M P S
Gears create voids as Gears create voids as they come out they come out of mesh and liquid flows into the of mesh and liquid flows into the cavitiescavities
As the gears come back into mesh, As the gears come back into mesh, the volume is reduced and the liquid the volume is reduced and the liquid is forced out of the discharge portis forced out of the discharge port
G E A R P U M P S
L O B E P U M P S
S C R E W P U M P S
C A M P U M P S
V A N E P U M P S
R O TA R Y P U M P S
As the teeth come out of mesh, As the teeth come out of mesh, liquid flows into the pump and liquid flows into the pump and is carried between the teeth is carried between the teeth and the casing to the discharge and the casing to the discharge side of the pump side of the pump
The teeth come back into mesh The teeth come back into mesh and the liquid is forced out the and the liquid is forced out the discharge portdischarge port
Fluid is carried between the rotor Fluid is carried between the rotor teeth and the pumping chamber teeth and the pumping chamber
The rotor surfaces create The rotor surfaces create continuous sealingcontinuous sealing
Rotors include bi-wing, tri-lobe, Rotors include bi-wing, tri-lobe, and multi-lobe configurationsand multi-lobe configurations
G E A R P U M P S
L O B E P U M P S
S C R E W P U M P S
C A M P U M P S
V A N E P U M P S
R O TA R Y P U M P S
Screw pumps carry fluid in the Screw pumps carry fluid in the spaces between the screw threads. spaces between the screw threads.
The fluid is displaced axially as the The fluid is displaced axially as the screws mesh. screws mesh.
G E A R P U M P S
L O B E P U M P S
S C R E W P U M P S
C A M P U M P S
V A N E P U M P S
R O TA R Y P U M P S
PPiston slide arm moves iston slide arm moves around inside a slot in the around inside a slot in the casing. casing.
AAn eccentric cam rotates the n eccentric cam rotates the circular plunger (shown in circular plunger (shown in gray) around the edge of the gray) around the edge of the casing, fluid is swirled around casing, fluid is swirled around the edge to the outlet port. the edge to the outlet port.
It is not in use now and is It is not in use now and is mainly of historical curiositymainly of historical curiosity. .
G E A R P U M P S
L O B E P U M P S
S C R E W P U M P S
C A M P U M P S
V A N E P U M P S
R O TA R Y P U M P S
G E A R P U M P S
L O B E P U M P S
S C R E W P U M P S
C A M P U M P S
V A N E P U M P S
R O TA R Y P U M P S
TThe vanes are in slots in the rotor. he vanes are in slots in the rotor. RRotor spins, centrifugal force pushes otor spins, centrifugal force pushes
the vanes out to touch the casing, the vanes out to touch the casing, where they trap and propel fluid. where they trap and propel fluid.
CENTRIFUGAL PUMPSCENTRIFUGAL PUMPS
WHAT IS CENTRIFUGAL PUMP?WHAT IS CENTRIFUGAL PUMP? WORKING MECHANISM OF A CENTRIFUGAL WORKING MECHANISM OF A CENTRIFUGAL
PUMPPUMP ADVANTEGAES AND DISADVANTAGES OF ADVANTEGAES AND DISADVANTAGES OF
CENTRIFUGAL PUMPSCENTRIFUGAL PUMPS
WHAT IS CENTRIFUGAL PUMP?WHAT IS CENTRIFUGAL PUMP?
Convert the mechanical energy into Convert the mechanical energy into hydraulic energy by centrifugal force hydraulic energy by centrifugal force on the liquidon the liquid
Constitute the most common type of Constitute the most common type of pumping machinerypumping machinery
Used to move liquids through a piping Used to move liquids through a piping systemsystem
Has two main components:Has two main components: 1. Stationary componets, casing, 1. Stationary componets, casing,
casing cover and bearingscasing cover and bearings2. Rotating components, impeller and 2. Rotating components, impeller and shaftshaft
Classified into three categories ; Classified into three categories ; Radial Flow, Mixed Flow, Axial FlowRadial Flow, Mixed Flow, Axial Flow
WORKING MECHANISM OF A WORKING MECHANISM OF A CENTRIFUGAL PUMPCENTRIFUGAL PUMP
Simplest piece of equipment Simplest piece of equipment in any process plantin any process plant
Energy changes occur by Energy changes occur by virtue of impeller and volutevirtue of impeller and volute
Liquid is fed into the pump at Liquid is fed into the pump at the center of a rotating the center of a rotating impeller and thrown outward impeller and thrown outward by centrifugal forceby centrifugal force
The conversion of kinetic The conversion of kinetic energy into pressure energy energy into pressure energy supplies the pressure supplies the pressure difference between the difference between the suction side and delivery side suction side and delivery side of the pumpof the pump
Liquid flow path inside a centrifugal pump
ADVANTAGES OF CENTRIGUGAL ADVANTAGES OF CENTRIGUGAL PUMPSPUMPS
AdvantagesAdvantages
Simple in construction and cheapSimple in construction and cheap Handle liquid with large amounts of solidsHandle liquid with large amounts of solids No metal to metal fitsNo metal to metal fits No valves involved in pump operationNo valves involved in pump operation Maintenance costs are lowerMaintenance costs are lower
DISADVANTAGES OF DISADVANTAGES OF CENTRIFUGAL PUMPSCENTRIFUGAL PUMPS
DisadvantagesDisadvantages
Cannot handle highly viscous fluids efficientlyCannot handle highly viscous fluids efficiently Cannot be operated at high headsCannot be operated at high heads Maximum efficiency holds over a narrow range of Maximum efficiency holds over a narrow range of
conditionsconditions
PUMPING PROBLEMSPUMPING PROBLEMSCavitation
Reduces the pump capacityReduces the pump capacity
CausesCauses metal removalmetal removal
reduced flowreduced flow
loss in efficiencyloss in efficiency
and noiseand noise
To avoid cavitation To avoid cavitation NPSH
POWER AND EFFICIENCY POWER AND EFFICIENCY CALCULATIONSCALCULATIONS
•The power supplied to the pump:
Where m=mass flow rate, kg/s H= total discharge head, N.m/kg =efficiency
…………(1)
•The power delivered to the fluid:
……………(2)
•From equations (1) and (2) efficiency:
PUMP SELECTIONPUMP SELECTION
The amount of fluidThe amount of fluid
The properties of the fluid The properties of the fluid
Type of power supplyType of power supply
Cost and mechanical efficiency of the pumpCost and mechanical efficiency of the pump
CAPACITY
LOW HIGH
GEAR LOBE CENTRIFUGAL
PRESSURE
SMALL OR MODERATE
MODERATEOR HIGH
ROTARY PLUNGER
or
ROTARY PISTON
RECIPROCATING or
RIGID SCREW
HIGHER
REFERENCES
1.1. http://en.wikipedia.org/wiki/Pumphttp://en.wikipedia.org/wiki/Pump
2.2. www.cheresources.comwww.cheresources.com
3.3. www.pumpworld.com/contents.htmwww.pumpworld.com/contents.htm
4.4. www.rpi.edu./dept/chem-eng/ www.rpi.edu./dept/chem-eng/ Biotech-Environ/PUMPS/intro.htmlBiotech-Environ/PUMPS/intro.html
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