There are many types of marine pumps in ship, they are important parts of ship auxiliary machinery. Mainly divided into two categories: marine water pumps and marine oil pumps, and the conveying media are mainly seawater, fresh water, sewage, diesel oil, lubricating oil, etc..

According to its function:

1. Serving the main engine plant, such as fuel supply pump, lubricating oil pump, fuel transfer pump, main sea water cooling pump, cylinder liner cooling water pump, oil head cooling water pump;
2. Serving auxiliary machinery, such as auxiliary boiler feed water pumps, cooling water pumps for refrigeration devices, sea water pumps for seawater desalination equipments, hydraulic pumps for steering gear or other deck machinery, etc.
3. Serving ship safety and living facilities, such as bilge water pumps, ballast water pumps, high pressure fire fighting pumps, marine eductor, daily fresh water pumps, daily sea water pumps, general pumps, etc.
4. Serving for special ships, such as cargo oil pumps for oil tankers, mud pumps for dredgers, salvage pumps for salvage ships, water jet propulsion pumps for water jet propulsion ships, fishing pumps for netless fishing boats, etc.

According to working principles:

1. Positive displacement pump
   Positive displacement pumps rely on the movement of working parts to periodically change the working volume of the pump to provide pressure energy to the liquid and to suck in and press out the liquid. According to the movement mode of moving parts, positive displacement pumps are divided into two types: rotary pumps and reciprocating pumps, and reciprocating pumps are further divided into piston pumps and plunger pumps; rotary pumps mainly include gear pumps, screw pumps, vane pumps and water ring pumps.
2. Impeller pump
   The impeller pumps rely on the impeller to drive the liquid to rotate at high speed to provide speed energy and pressure energy to the liquid and to suck and discharge the liquid. According to the different structural characteristics of the impeller and flow channel of the pump, it can be divided into centrifugal pump, axial flow pump, mixed flow pump and vortex pump.
3. Jet pump
   The jet pump relies on the high-speed jet generated by the working fluid to eject the fluid to be discharged, provides energy to it through momentum exchange, and discharges it. Depending on the working fluid used, there are water jet pumps, steam jet pumps and air jet pumps.

Marine pumps can also be divided into the following forms:

1. According to the driving mode, it can be divided into electric motor drive, diesel engine drive and steam turbine drive
2. According to the number of impellers, it can be divided into single-stage pumps, two-stage pumps and multi-stage pumps
3. According to the position of the pump shaft, it can be divided into vertical pump and horizontal pump
4. According to the number of suction ports, it can be divided into single suction pump and double suction pump