Date post: | 19-Jan-2015 |
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Dr. C. L. JonesBiosystems and Ag. Engineering
Pumps – Lectures 1• Outline:• Where are pumps used• Pumps, fans, compressor differences• General HP and mechanical efficiency• Types of Pumps
– Displacement– Dynamic
• Reading: – Handouts:
• ITT Goulds Pumps Centrifugal Pump Fundamentals (in class) read all • Fluide Design Inc. Centrifugal Pump Fundamentals (download)
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Dr. C. L. JonesBiosystems and Ag. Engineering
Pumps, Fans, Compressors--Turbomachines
• Turbomachines: change energy level of flowing fluid by means of momentum exchange
• 2nd only to electric motors in number• Wide spread in ALL industries
– Power units: cars/trucks, tractors– Computers– Grain elevators– Oilfield– Water supply/treatment– Food processing– And…….
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Dr. C. L. JonesBiosystems and Ag. Engineering
Pumps, Fans, Compressors--Turbomachines
• Differences between pumps, fans, compressors– Pumps: move liquids– Fans: move gases with little increase in
pressure– Compressors: move gases with greater
increase in pressure
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Dr. C. L. JonesBiosystems and Ag. Engineering
Mechanical Efficiency
• Ratio: • Power Output:
• English Units, HP:
• Efficiency
PowerOutput
PowerInput
oP WQ g
1714o
QPP
om
i
Pe
P
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Pump example 1
• A pump provides 0.009 m^3/s of water and total head of 10.6 m. Determine the power output of the pump. If the power input is 1310 W, determine the mechanical efficiency of the pump.
• Pump Example 2, English Units– Will be shown in class
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Dr. C. L. JonesBiosystems and Ag. Engineering
Pumps
• Two typesFlow rates Pressure Flow
characteristics
Displacement
- plunger
- piston
- rotary
Low High Pulsating
Dynamic
- centrifugal
- jet
- airlift
High Low Steady Flow
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Dr. C. L. JonesBiosystems and Ag. Engineering
Displacement Pumps
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Dr. C. L. JonesBiosystems and Ag. Engineering
Displacement Pumps
• Reciprocating and Piston Pumps– Crank– Connecting rods– Pistons or plungers– Vol. efficiencies > 97%, Mech. eff. approx. 90% – For more stable flow, increase number of
cylinders
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Dr. C. L. JonesBiosystems and Ag. Engineering
Displacement Pumps
• Rotary Pumps (gear, lobe, screw, vane)– Most popular: gear pumps– 90%+ mechanical eff.– Relatively constant output
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Dr. C. L. JonesBiosystems and Ag. Engineering
Dynamic Pumps
• Centrifugal– Relative simplicity– Mech. eff. as high as 90%– Can handle fluids containing suspended solids– Ease of maintenance…good for food products– 2 parts: impeller and casing– Radial, mixed, axial flow
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Dr. C. L. JonesBiosystems and Ag. Engineering
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Dr. C. L. JonesBiosystems and Ag. Engineering
Performance Curves