轮机 外派 面试 超级实用(玉女版九阴真经).docVIP

M/E How does a marine diesel engine work? A charge of fresh air is pumped into the engine cylinder and then compressed by the moving piston to a very high pressure. When the air is compressed, its temperature rises so that it ignites the fine spray of fuel injected into the cylinder. The burning of the fuel adds more heat to the air charge, causing it to expand and force the engine piston to do work on the crankshaft which in turn drives the ships propeller. four stroke of the engine : Suction Compression Expansion Exhaust It takes two revolutions to make one power stroke for a four stroke engine. Before a large diesel started it must be warmed through by circulating hot water through the jackets This will enable the various engine parts to expand in relation to one another. Boiler 1. The function of the boiler: Boiler is use to heat feed water to produce steam to heat the fuel oil and lube oil and the galley needs the steam to heat foods too. A drum must be provided where steam and water can separate. The types of the marine boiler Fire tube boilers: The furnace hot gases pass through the tubes while the water is on the outside. Water tube boilers The water through the tubes while the hot furnace gases pass around the outside What is the commonly used boiler? Exhaust boiler and oil-burning boiler. Boiler mountings: Safety valves; Main steam stop valve; Auxiliary steam stop valve; Water level gauge; Blow down valve; Scum valve; Soot blowers. Marine pump 1. A pump is a machine used to raise liquids from a low point to a high point. 2. There are three main classes of pump in marine use 1.displacement 容积式泵 2.axial flow 轴流式泵 3.centrifugal 离心泵 3. An air vessel usually fitted in the discharge pipe to dampen out the pressure variations during discharge. 4. A diffuser is fitted to convert the kinetic energy (energy of motion) of the liquid into pressure energy Marine Electrzation A current is produce when