Articles

What Is Marine Pumps

Author : Bozhou Marine

Update time : 2022-09-08 09:33:03

Marine pumps refer to various pumps for ships that meet the requirements of ship specifications and marine technical conditions. On board, they are often used to deliver seawater, fresh water, sewage, lubricating oil, fuel oil and other liquids.

Marine pump refers to the machinery used on ships to increase the pressure or potential energy of liquid and liquid materials to make them flow.
Generally, pumps must be used to transport liquid to higher positions, longer distances and higher pressures. Pumps can also be used to generate high-pressure liquid for hydraulic transmission. The pump is driven by an electric motor or other prime mover. The characteristics of marine pumps are as follows: when the ship swings and tilts, the pump shall not suffer cavitation due to the fluctuation of suction liquid level; In order to reduce the occupied area of the pump and facilitate maintenance, the vertical structure is generally adopted; The flow passage parts are made of bronze, brass or stainless steel to minimize corrosion.

Marine pumps are widely used in modern ships. Generally speaking, a diesl powered cargo ship needs 36 ~ 50 pumps of various types, accounting for 20% ~ 30% of the total mechanical equipment of the ship. Marine pumps are widely used in modern ships.

Marine pumps can be divided into:

(1) Pumps for marine power plants. There are fuel oil pumps, lubricating oil pumps, seawater pumps, freshwater pumps, hydraulic pumps of steering gear or other deck machinery, feed water pumps of boiler units, cooling water pumps of refrigeration units, seawater pumps and condensate pumps of seawater desalination units.

(2) General purpose pumps for ships. There are bilge water pumps, ballast water pumps, fire pumps, daily fresh water pumps, daily seawater pumps, hot water circulation pumps, and general pumps that are also used as ballast water pumps, fire pumps and bilge water pumps

(3) Special pumps for special ships. Some special-purpose ships are also equipped with special pumps for their special operation requirements, such as cargo pumps of oil tankers, mud pumps of dredgers, salvage pumps on fishing vessels, water jet propulsion pumps on water jet propulsion vessels, and fishing pumps on fishing trawlers.

According to the different working principles of pumps, marine pumps are mainly divided into the following categories

(1) Positive displacement pump

The positive displacement pump sucks and discharges liquid by the periodic increase and decrease of the working volume caused by the movement of the working parts. When the working volume increases and the pressure decreases, it sucks in liquid, when the working volume decreases and the pressure increases, it discharges liquid, and directly increases the pressure of liquid by squeezing. According to the different movement modes of moving parts, it can be divided into reciprocating pumps and rotary pumps. The former includes piston pump and plunger pump; The latter include gear pump, screw pump, vane pump, etc

(2) Sichuan vane wheel pump

The wheel counting pump drives the liquid to rotate at a high speed by means of the impeller, which continuously generates suction and discharge, transmits mechanical energy to the liquid to be conveyed, increases the pressure of the liquid, and achieves the purpose of conveying the liquid. According to the different characteristics of the impeller and flow channel structure of the pump, it can be divided into centrifugal pump and vortex

(3) Jet pump

The jet pump generates high-speed jet ejecting fluid in the nozzle by working fluid with certain pressure, and then increases the energy of the ejected fluid through momentum exchange. According to the different working fluids used, pumps can be divided into water jet pumps, steam jet pumps and air jet pumps. In addition to being classified according to different working principles, pumps can also be divided into vertical pumps and horizontal pumps according to the position of pump shafts; Divided into single suction pump and double suction pump according to the number of suction ports;
According to the prime mover driving the pump, it is divided into electric pump, steam pump and diesil pump. Generally, the pump is used on the ship.The function is named for the pump, such as the seawater cooling pump of the main engine and the lubricating oil pump of the main engine.

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