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Pumps

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Pumps

Displacement

pumps

Centrifugal

pumps

Reciprocating

pumpsRotary pumps

Flexible impeller pumps

Single stagepumps

Multi-stage pumps

Depends on principle ofthe work of the pumps

Screw pumps

Vane pumpsSpecial geometry

pump

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In some sources Displacement and Centrifugal pumps are split in groups differently comprising more applications

We are interested in marine applications!!!

http://www.pumpworld.com/tutorials.htm

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pumps

• A.C. motor—driven pumps

• D.C. motor—driven pumps

• Engine driven pumps

• Hydraulically driven pumps

• Manual pumps

Depends on forms of drive

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Characteristics of the PUMPS

• Head (vertical lift) measured in meters or feet• Capacity measured in litres per minute or gallon

per hour • Relation between head pressure and capacity• Self-prime or not self-prime• Ability to run dry (work out scenario of use)• Ability to passing solids• Chemical tolerance• Continuous duty

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Displacement pumps

• Self prime• Efficient for dealing with

small volumes and high differential pressure or head

• Can handle any required viscosity

• Can tolerate or not solids depends on the valve construction

• Dry run tolerance depends highly on the construction

• Valves and diaphragms could be susceptible to chemical damage

Displacement Reciprocating pump

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Displacement Reciprocating pumps

• Double acting

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Displacement Diaphragm pumps

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Displacement Variable volume impeller pumps

Flexible impeller pump

Vane pump

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Displacement Screw Pump

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Centrifugal pumps

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Centrifugal pumps• Not self-prime – position bellow liquid level

or to be primed• Widest application for dealing with large

volumes with a medium—to—low heads and viscosities

• Moderate tolerance for solids – the large the pump, the more tolerant

• Can run dry• May have chemical tolerance depends on

the sealing type

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Centrifugal pump performance curve

All pump manufacturers have a graphs that show pump output as a function of head pressure

Total head include required head of the system plus all losses, expressed in head pressure

bilge

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Blockage of the discharge

• Centrifugal pump – simply responds by moving less fluid until it spins to no effect – the current drawn drops down

• Displacement pump – builds up the pressure and loads the motor – the current drawn increases. This process continue until something will burn, break or pipe-work burst out

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When chose pump

• Check with care in the pump manufacturer manual or instructions how well pump characteristics (slide 5)meet system requirements!!!