2016年2月21日星期日

Marine Pump Introduce






Pump is a ship widely used hydraulic machinery, it consists of a prime mover drive, and the mechanical energy into fluid pressure energy, potential energy and kinetic energy. Pump medium liquid is water and oil.

In order to pump water, fresh water, fuel, oil and other liquids, the need for a certain amount and different type of pumps. Generally in the engine room must be set bilge pump, fuel pump and oil pump, boiler feed pump, cooling pump, ballast pump, sanitary pump and other major pumps.

In the marine machinery and equipment, marine pump is a large number, variety and important ship matching products. It is widely used in ship power system, fire protection system, cooling system, pressure loading system, stripping system, life security services and other special system, but also be equipped in certain auxiliary devices. In recent years, the domestic ship large, ship type diversification, the trend of the whole ship automation is increasingly obvious.

In general, the number of various types, different uses pump total number accounted for 20-30%, the total power of ship's equipment 5-15%. In addition, marine pumps have been widely used in marine engineering equipment, docks, port terminals, etc.

Summary
Pump is to increase the liquid and liquid material pressure or flow. Deliver liquid to a higher location, distance, higher pressure must use the pump, the pump can also be used to produce high pressure liquid for hydraulic transmission. Motor driven by electric or other.according to the working principle can divided into vane pump, (such as centrifugal pump, mixed flow pump, axial flow pump, vortex pump), displacement pump (reciprocating pump, rotary pump) and other types of pumps, (such as jet pump, electromagnetic pump, etc.); according to the structure is divided into vertical pump horizontal pump, self- priming pump and non self- priming pump; according to use can be divided into dynamic pumps (such as boiler pump, condensate pump, circulating pump, fuel pump, lubricating oil pump and cooling water pump, etc.) and ship system pump( ballast pump, bilge pump, water pump, sanitary pump, fire pump, cargo oil pump, vacuum pump, mud pump and fishing pump, etc.) Flow rate and head are the two main parameters of pump.

Marine pump features: requirements pump when ship sway and incline, not due to inhalation of level fluctuation have cavitation occurs; in order to reduce the occupied area of pump and convenient maintenance, general use vertical structure; through flow components are made of bronze, made of stainless steel and other materials, to as much as possible to reduce corrosion.

classification
Marine pump has a very wide range of applications in ships, according to different purposes, can be divided into:
1, marine power plant pump
With fuel pump, lubricating oil pump, seawater pump, fresh water pump, steering gear or other hydraulic deck machinery hydraulic pump, boiler device water feed pump, cooling water pump, sea water desalination device of water pump and condensate pump.
Bilge pump, ballast pumps, fire pumps, daily fresh water pump, daily water pump, hot water circulation, and doubles as a pressure load, fire protection, bilge general pump.
Some special purpose ship, also has special operation requirements and special pump provided, such as oil tanker cargo oil pump, hopper dredger mud pump, salvage ship salvage pump, spray propulsion ship water boost pump, no net fishingship fishing pump.


According to the working principle, the marine pump mainly has following categories:
1, volume type pump
Positive displacement pump is by the movement of working parts caused by volume of work periodically changes and liquid smoke platoon. When working volume increases, and the pressure is dropped inhalation liquid, when working volume decreases and pressure discharging liquid, by crushing the pressure of liquid can increase. According to the way of moving parts, it can be divided into reciprocating pump and rotary pump. The former has a piston pump and cylinder pump, the latter has a gear pump, screw pump, vane pump, etc..
2, vane pump
Impeller pump mainly by increasing the liquid kinetic energy to increase the liquid energy. It relies on the impeller to drive liquid for high-speed rotary motion, continuous production of suction and discharge, the mechanical energy can be transferred to the liquid delivery, so that the liquid pressure can be increased, and to achieve conveying liquid. According to different characteristics of pump impeller and flow channel, it can be divided into centrifugal pump and vortex pump.
3, jet pump
Jet pump is a working fluid with a certain pressure to produce high speed jet injection fluid in the nozzle, and then through the momentum exchange, the energy of injection fluid is increased. According to different working fluid, it can be divided into water jet pump, steam ejector and air ejector.
Pump in addition to classification according to the working principle, can also according to position of pump shaft is divided into horizontal pump and vertical pump; according to number of suction inlet is divided into single suction pump and double suction pump; divided by prime mover driven into electric pump, steam pump and diesel pumps, marine pump most electric pump and emergency fire pump is directly driven by a diesel engine, cargo oil pump often consists of a steam turbine drive.

Performance parameter
In order to explain the basic working performance of pump , convenient select and compare the performance of pump , usually expressed in the following parameters.
1, displacement
Pump displacement refers to the amount of liquid discharged or transported by pump in the unit time, often expressed in volume displacement, and its unit is m3/h.
2, pressure head
Pump pressure head is used to overcome the resistance of suction and exhaust pipe and the suction and discharge of liquid level of the pressure difference, pressure liquid to a certain height of the energy. the pressure difference between the suction and discharge ports can be approximately measured by the pressure difference between suction and discharge ports. It is expressed as a unit of liquid in the flow through pump the pressure can be obtained.
3, power and efficiency
Power is usually expressed as power and output power is expressed in kilowatts. Pump efficiency is the ratio of the output power to the shaft power, and it is the index of pump work economy.
4, speed
Refers to the pump shaft rotation per minute, unit is R / min. Reciprocating speed can also be used in the double stroke piston number per minute completed said.


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