Lesson19FreshWaterGenerator.doc

Lesson 19 Fresh Water Generator 第19课 造水机 1. Fresh water is generated on ship by a fresh water generator，also known as evaporator. The process by which fresh water is generated is known as distillation process. Sea water is converted into fresh water by evaporating and condensing the sea water. Evaporation of the sea water is either done by boiling or by flash process. Fresh water generators can be shell-and-tube type or plate type. 船上的淡水由造水机(也称蒸发器)生产。淡水产生的过程也叫蒸馏过程。通过蒸发和冷凝海水，海水转化为淡水。海水的蒸发是通过沸腾或闪发过程完成。造水机可以是壳管式或板式。 2. A fresh water generator consists of mainly two parts. A condenser and an evaporator. The boiling process is done either by a heating coil or by using the high temperature main engine jacket water. Generally water is boiled at 100℃, but in a fresh water generator it is done at around 60—70℃ or even lower for some modern types. For this purpose, eductors or air ejectors are used. Ejectors reduce the chamber’s pressure to such a point that water starts boiling at a lower temperature. 造水机主要由冷凝器和蒸发器两部分组成。蒸发过程通过加热盘管或高温的主机缸套冷却水来实现。通常水的沸点是100℃，但是在造水机中沸点只有60-70℃，在一些现代机型中甚至更低。为了达到这个目的，使用空气抽吸器或喷射泵。喷射泵降低内部的压力使得海水在较低的温度下沸腾。 The following will describe a modern type of Alfa Laval fresh water generator: 3.下面将描述一台新型的阿尔法拉法造水机: 3. This fresh water generator uses vacuum distillation to convert sea water into high- quality fresh water and is designed for automatic operation in periodically unmanned engine rooms and other automated operations. Its capacity may range from 4 to 35 m3/24h，depending on the heating medium and cooling water temperatures. The fresh water generator can be dimensioned to suit any jacket water temperature from 55—95℃ at any cooling water temperature required. The quantity of fresh water produced can be altered by varying the number of plates in the heat exchanger assemblies. 这种造水机采用真空蒸馏将海水转换成高质量的淡水，可用于定期无入机舱的自动操作和其他自动操作。根据加热介质和冷却水温度，它的产水量可以达到每天4 ~35 m3。造水机的结构尺寸能够符合任何55 -95℃的缸套冷却水。通过改变热交换器换热板组件的数量可以调节淡水的品质。 4. The basic equipment of the fresh water gen