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Lebanese International University

Pump Technology (MENG 570)Pump Technology (MENG 570)Spring 2014 (Lecture 3) 

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Instantaneous Discharge

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Instantaneous Discharge

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Constant Discharge Pump

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Variable Discharge Pump

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No Acc. No Acc.

Max Acc.

Or    Pmin > Pvap ‐ Patm

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Cavitation with Inertia

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Air Vessels

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Advantages of Air Vessels

• The advantages of installing air vessels are:

• The flow fluctuation is reduced and a uniform flow is obtained.

Th f i i k (h d) i d d• The friction work (head) is reduced.

• The acceleration head is reduced considerably.

• Enables the use of higher speeds.

• Avoid Cavitation

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No inerrtia h

ead

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Q instantaneous

I ti H dInertia Head

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Multi‐Cylinder Pumps

• single‐cylinder,

single‐acting pump

• Single‐cylinder• Single‐cylinder,

double‐acting pump

• Two‐cylinder, 

double acting pump

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Advantage of Multi‐Cylinders

WHY?? 

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Max Acc.

60o

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