Transcript Pumps
Pumps 1 Depends on principle of the work of the pumps Pumps Displacement pumps Reciprocating Rotary pumps pumps Flexible impeller pumps Vane pumps Centrifugal pumps Single stage pumps Multi-stage pumps Screw pumps Special geometry pump 2 In some sources Displacement and Centrifugal pumps are split in groups differently comprising more applications http://www.pumpworld.com/tutorials.htm We are interested in marine applications!!! 3 Depends on forms of drive pumps • • • • • A.C. motor—driven pumps D.C. motor—driven pumps Engine driven pumps Hydraulically driven pumps Manual pumps 4 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 5 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 6 Displacement Reciprocating pump Displacement Reciprocating pumps • Double acting 7 Displacement Diaphragm pumps 8 Displacement Variable volume impeller pumps Flexible impeller pump Vane pump 9 Displacement Screw Pump 10 Centrifugal pumps 11 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 12 Centrifugal pump performance curve bilge 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 13 14 15 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 pipework burst out 16 When chose pump • Check with care in the pump manufacturer manual or instructions how well pump characteristics (slide 5)meet system requirements!!! 17