1 Pumps

2 Displacement pumps Centrifugal pumps Reciprocating pumps Rotary pumps Flexible impeller pumps Single stage pumps Multi-stage pumps Depends on principle of the work of the pumps Screw pumps Vane pumps Special geometry pump

3 In some sources Displacement and Centrifugal pumps are split in groups differently comprising more applications We are interested in marine applications!!!

4 pumps A.C. motor—driven pumps D.C. motor—driven pumps Engine driven pumps Hydraulically driven pumps Manual pumps Depends on forms of drive

5 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

6 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

7 Displacement Reciprocating pumps Double acting

8 Displacement Diaphragm pumps

9 Displacement Variable volume impeller pumps Flexible impeller pump Vane pump

10 Displacement Screw Pump

11 Centrifugal pumps

12 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

13 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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16 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

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