Marine pumps ships centrifugal pumps displacement pumps

There are mainly two types of marine pumps:

  • Displacement pumps
  • Centrifugal pumps

Displacement pumps:

This pump uses the mechanical variation of the volume of a chamber to displace a gas or a liquid from suction to the discharge. These pumps are self priming and their output is almost directly proportional to its speed . These pumps can handle large amounts of gases , so it enables the pump to deal with volatile or hot liquids. These pumps are not suitable for high speed and large capacities.

There are two types of displacements pumps namely:

  • Reciprocating Displacement pumps: In this type of displacement pump the piston is reciprocated in a liquid cylinder. These pumps need inlet and outlet valve arrangements .                                                                                      
  • Rotary Displacement pumps: In rotary pumps the liquid is forced through the suction to the discharge  by gears or screws. These pumps  don't need inlet and outlet valve arrangements as reciprocating pumps . In general the rotary pumps can be classified into four:
  1. Gear and screw pumps
  2. Rotary vane pumps
  3. Lobe pumps
  4. Special geometric forms

Centrifugal pumps:

Centrifugal force imparted to the liquid by the rotation of impeller will induce the flow through the pumps. These pumps are not self-priming. Centrifugal pumps are primed by gravity supply or priming equipment external or integral with the pump. Centrifugal pumps  convert external driving energy to kinetic energy in the fluid by giving impulses to fluid by impellers. This type of pumps are suitable in every cases other than very small capacities or speeds.