1.Boilers are used on board ship for producing steam. 船上使用锅炉来产生蒸汽 This steam may be used for driving the main engines, When steam turbines are fitted. 当安装了蒸汽透平时， 蒸汽可用来驱动主机,Or for driving auxiliary machinery such as the windlass. 或者用来驱动辅助机械，比如锚机,There are two basic types of boiler in use on board ships: 船用锅炉有两种基本类型：the fire tube boiler (the terms “smoke tube” and “donkey boiler” are also in use), 火管锅炉(也使用烟管锅炉和辅锅炉这两个术语),and the water tube boiler, both are illustrated in Fig.9-1.,和水管锅炉分别如图9-1所示。
2. Now if you look at the diagram of the fire-tube boiler you will see that it consists of a cylindrical steel shell, which contains a furnace at the bottom.,现在来看看火管锅炉的简图，你会发现它由一个圆筒形的钢质外壳构成,底部有炉膛Two or more furnaces may be fitted, depending on the size of the boiler. The furnace is connected to a combustion chamber, situated in the middle part of the boiler.,根据锅炉尺寸的大小，可以安装两个以上的炉膛炉膛和位于锅炉中间位置的燃烧室相连通Leading from this combustion chamber to a smoke box are a large number of horizontal tubes .,燃烧室和烟箱之间有许多水平管道(烟管),some of these are used for supporting the middle section of the boiler and the combustion chamber. Connected to the smoke box are the uptakes for the waste gases. The furnace, the combustion chamber and the tubes are all surrounded by water.,一部分烟管用来支撑锅炉中部和燃烧室。
与烟箱相连的是废气的上升通道炉膛，燃烧室和(烟)管都被水环绕着,3. The fire-tube boiler is usually of both riveted and welded construction. It is strong and is capable of operating with poor quality feed water.,火管锅炉通常是铆接和焊接结构其结构坚固，并能使用劣质给水工作But there are more efficient types of boiler, which can generate more power; therefore fire-tube boilers are now mainly chosen for low-pressure steam production on vessels requiring steam for auxiliary purposes,但是，有些类型的锅炉效率更高，能产生更多的蒸汽；因此，火管锅炉现在主要被用来提供低压蒸汽给需要的辅助场合(目的)的船舶4. Water-tube boiler have replaced fire-tube boilers for generating high-pressure, high- temperature, high-capacity steam for main engines or cargo pump turbines.,水管锅炉已经代替了火管锅炉来产生高压、高温、大量的蒸汽，以驱动主机或者货油泵的透平。
From the diagram you will see that they have a steam drum at the top, which is partly filled with water, and water drums at a lower level. These drums are connected by banks of tubes, which also contain water.,从图上可以看到，水管锅炉顶部有一个汽鼓，部分有水，且下部有多个水鼓这些汽鼓和水鼓通过管束相连，管内也有水The furnace is located at the bottom and the whole system is contained in a fireproof casing. Downcomer tubes are placed outside the gas system to act as feeders to the water drums.,炉膛位于底部，整个系统由防火外壳包围下降管安装在燃气系统之外，用作水鼓的给水管5. Gases are heated in the furnace and pass up wards through the banks of tubes, transferring their heat to the water in the tubes . because the steam drum provides a reservoir of relatively cool water, convection currents are set up causing the water to circulate round the system.,在炉膛内被加热的燃气向上通过管束，把热量传递给管内的水。
因汽鼓内储存的水温度相对较低，系统内就形成了对流，使水得以循环,The banks of tubes (generating tubes) offer a large surface area to the radiant heat of the furnace gases. This makes them very efficient. Super-heaters are added to the system to increase its efficiency. These are located between the rows of tubes.,管束(蒸发管)提供了一个很大的炉膛辐射受热面，这使其效率很高过热器被安装在系统中，以增加其效率，(过热器)安装在管束中间6. Various valves and gauges are fitted to the boilers. Those attached directly to the pressure parts of the boiler are known as boiler mountings. The mountings usually found on a boiler are: safety valves, which are needed to protect the boiler against overpressure; a main stop valve in order to control the passage of steam to the engines;,锅炉上装有各种不同的阀和仪表.直接和锅炉的压力部分相连的称为锅炉附件。
通常锅炉上的附件有：安全阀，用来保护锅炉压力过高主停汽阀，用来控制通向发动机的通道feed check valves to control the final entry of water into the boiler; water level indicators to show the level of water in the boiler; a blow-down valve enables water to be blown down or emptied from the boiler,给水止回阀，用来控制锅炉进水量水位计，用来显示锅炉水位下排污阀，用来下排污或放空炉水a scum valve enables the blowing down or removal of scum and impurities from the water surface and thermometers for showing the temperature inside the boiler.,上排污阀，用来排出或除去锅炉水面上的浮渣和杂质温度计，用来显示锅炉内部的温度In order to be able to blow away soot and the products of combustion from the tube surfaces, soot blowers are fitted which are operated by steam or compressed air.,为了吹除管壁上的烟灰和燃烧产物，安装了用蒸汽或压缩空气工作的吹灰器。
Salinometer valves are also fitted to allow samples of water to be drawn off for testing. Chemical dosing valves are also necessary so that chemicals can be added directly into the boiler.,盐度计(取样)阀也安装在锅炉上，以取锅炉水样进行化验还需要安装投药阀，以便化学药品能直接投入锅炉中。