Lab #4 Pumps and Pipe Friction - Nc State UniversityGoals of Lab • Familiarization with different...

Lab #4Pumps and Pipe Friction

Outline• Goals of lab• Experimental setup• Manometer• Types of pumps

– Positive displacement (piston, gear, lobe), centrifugal• Types of valves

– Plug, ball, gate, globe, butterfly• Types of bends

– Short radius, long radius, elbow bend, mitre bend• Other fittings

– Tee, Y, expander/reducer 2

Goals of Lab

• Familiarization with different types of pumps, valves, and fittings in a pipeline

• Determine the coefficient of friction, 'Cff ', for different fittings (long bend, short bend, elbow bend, mitre bend, and gate valve), Cfc (for contraction), and Cfe (for expansion) in the pipes

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Experimental Setup

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Manometer

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Types of Pumps• Centrifugal pump

– Product enters impeller of pump at center and exits tangentially (energy is applied constantly)

– Generally used for high flow rates and low viscosity products– Flow rate depends not only on speed of rotation of impeller, but also on

viscosity of product and pressure downstream– Requires priming (pump casing must be filled with product before

starting pump; otherwise pump cannot work)– Simple, light, low wear & tear, low maintenance

• Positive displacement (PD) pump– Product entry point and exit point vary depending on type of PD pump

(energy is applied intermittently)– Generally used for low flow rates and high viscosity products– Flow rate depends only on speed of moving part in pump– Does not require priming– More complicated, heavy, higher wear & tear, higher maintenance 6

Centrifugal Pump

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Positive Displacement Pump(Piston Pump)

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Reservoir Reservoir

Intake Open Intake Closed

DischargeClosed

DischargeOpen

Suction Stroke Discharge Stroke

Positive Displacement Pump(External Gear Pump)

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Positive Displacement Pump(Lobe Pump)

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Plug Valve

Rubber plugMetal plug 11

Ball Valve

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Open Closed

Gate Valve

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Globe Valve

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Butterfly Valve

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Elbow• Used to change direction of flow/piping• They may be flanged or threaded• They are usually 45 or 90° bends• Types of elbows

– Curved• Short radius (radius = pipe diameter)• Long radius (radius = 1.5 * pipe diameter)

– Mitre

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1.5D

3D5D

Tee and Y• These are used to combine or split flow• Friction and pressure drop in a Y will be less than

that in a tee

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Reducer/Expander• Used to connect pipes of different diameters• Types of reducers

– Concentric• The levels of the two pipes will be different

– Eccentric• Top or bottom level of pipes can be maintained at same level

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