Lesson-19-Fresh-Water-Generator.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 6070 or even lower for some modern types. For this purpose, eductors or air ejectors are used. Ejectors reduce the chambers 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 5595 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 generator includes titanium plate heat exchangers for evaporator and condenser, generator shell, two-stage brine/air ejector, fresh water pump and fresh water control sensor and frame. Additional equipment necessary for operation includes: a combined cooling and ejector water pump with an electric motor, a control panel with motor starters and a salinometer and a feed water anti-scale chemical dosing unit (necessary at heating medium temperatures above 75).造水机的基本设备包括用于蒸发器和冷凝器的钦板换热器、造水机壳管、二级海水空气喷射泵、淡水泵和淡水感应控制器。(造水机)工作时需要的附加设备包括:带电机的冷却水泵和抽气泵的组合装置，带电机启动器和盐量计的控制屏以及给水防结垢药剂添加装置(加热介质温度有必要高于75)。5. When working (see Fig. 19-1) ，the feed water to be distilled is taken from the sea cooling water outlet of the condenser (1). It enters the evaporator (10) where it evaporates at about 4060 as it passes between the plates heated by the heating medium. The evaporating temperature corresponds to a vacuum of 85%-95%，maintained by the brine/air ejector. The vapours generated pass through a demister where any drops of sea water en trained are removed and fall due t o gravity to the brine sump at the bottom of the generator chamber. The clean fresh water vapours continue to the condenser (9)，where they condense into fresh water as they pass between the cold plates cooled by the sea cooling water工作时(见图19-1)，被蒸馏的给水来自冷凝器(1)海水管路出口。海水进入蒸发器(10)，随着穿过加热介质加热的板，在40-60蒸发沸腾，对应的是85%-95%的真空，真空由海水/空气喷射泵来维持。产生的蒸汽通过除雾器时，海水滴被去除，然后由于重力的作用落入造水机底部的盐水池。洁净的水蒸气继续进入冷凝器(9)，它们穿过海水冷却的换热板时冷凝成淡水。6. The heating medium is either engine jacket cooling water or a closed circuit heated by steam. The ejector pump is separately installed and has separate suction from the sea. This pump supplies coolant in the form of sea water to the condenser，feed water for evaporation and water for the combined brine/air ejector. The fresh water produced is pumped to the tank by the built-in fresh water pump. The separately installed control panel，with motor starters and salinometer，supplies electrical power to the ejector and fresh water pumps and control voltage to the salinometer and dump valve. This salinometer is provided together with an electrode unit fitted on the fresh water pump delivery side. If the salinity of the fresh water produced exceeds the permitted maximum value，the solenoid valve and alarm are then activated to automatically dump the fresh water produced into the bilge.加热介质可以是主机缸套冷却水或由蒸汽加热的闭合回路。喷射泵独立安装，有单独的海水吸入端。这个泵以海水作为冷却介质进入冷凝器，为蒸发器和真空泵提供水源。产生的淡水通过内置的淡水泵进入淡水柜。独立安装的控制面板带有电机启动器和盐度计，为喷射泵和淡水泵提供动力并且控制盐度计和安全阀的电压。与盐度计相连的电极单元在淡水泵的排出侧。如果所产淡水含盐量超过允许的最大值，电磁阀和报警器就会工作，自动将所产淡水排至舱底水。7. Starting procedure启动步骤1) Open the valves on the suction and discharge side of the ejector pump.1)打开喷射泵的吸入阀和排出阀。2) Open the overboard valve for combined air/brine ejector.2)打开真空泵的舷外排出阀。3) Close the air valve on the upper part of the separator vessel.3)关闭造水机上部的空气阀。4) Set the main switch to position “ON”.4)合上主开关。5) Start the ejector pump. Check the pressure before ejector and after it.5)启动喷射泵，检查入口和出口压力。6) When there is a minimum of 90% vacuum，open the hot water inlet and outlet valves from the jacket cooling system.6)当达到90%真空时，打开来自缸套冷却水系统的热水进口阀和出口阀。7) Start the hot water supply to the evaporator section by adjusting the by-pass valve until the desired jacket water temperature difference is reached and ensure the boiling temperature inside the generator is about 45.7)开始向蒸发器供水加热，通过旁通调节达到理想的缸套冷却水温差，并确保造水机内部的沸腾温度在45左右。8) Start the fresh water pump. When the salinity level drops below the set alarm point，set the alarm on. It should be noted that improper or too low hot water flow will result in low boiling water temperature and a drop in the fresh water production.8)启动淡水泵。当盐度下降到低于设定的报警点时，打开报警器开关。应当注意，加热水的流速不稳定或过低会导致水的沸点较低和淡水产量下降。9) If the salinity of produced water is higher than the set alarm point，dumping it to bilge is recommended. The solenoid valve stays open. When evaporation starts，the boiling temperature rises，while the vacuum achieved drops to approximately 93%. After a few minutes，normal vacuum and boiling temperature are reestablished, salinity drops below the set alarm point and the solenoid valve closes.9)如果淡水的含盐量高于设定的报警点，建议排入舱底水。电磁阀保持开启状态。当真空下降到约93%时，蒸发开始，沸点升高。过数分钟后，正常的真空和沸点重新建立，盐度下降到低于设定值，电磁阀关闭。8. Stopping procedure停止步骤1) Stop the hot water supply to evaporator section. Stop the fresh water pump.1)停止供给蒸发器热水，停止淡水泵。2) Turn the alarm off.2)关闭报警装置。3) Stop the ejector pump.3)停止喷射泵。4) Set the main switch to position “OFF”.4)将主开关断开。5) Open the air valve.5)打开空气阀。6) Close the valves on the suction and discharge side of the ejector pump.6)关闭喷射泵的吸入阀和排出阀。7) Close the overboard valve for combined air/brine ejector.7)关闭喷射泵的舷外排出阀。B. Multiple Choice选择题Questions 1-3 are based on paragraphs 1-2. 根据课文第1-2段回答问题1-3.1. The process by which fresh water is generated is known as _ process.产生淡水的过程称为_过程。答案-AA. distillation蒸馏 B. evaporation蒸发C. condensation冷凝. D. flash闪发2. The boiling process is done either by _ or by _.沸腾过程通过_或_来实现。答案:cA. a heating coil/using the exhaust gases加热盘管/利用废气B. a heater/using the auxiliary engine jacket water加热器/利用辅机缸套冷却水C. a heating coil/using the high temperature main engine jacket water加热盘管/利用高温主机缸套冷却水D. a boiler/using the high temperature main engine jacket water.锅炉/利用高温主机缸套冷却水3. What devices are used to reduce the chambers pressure so that water starts boiling at a lower temperature?使用什么设备降低内部的压力使得海水在较低的温度下沸腾?答案;DA. Fresh water pumps. 淡水泵。B. Evaporators. 蒸发器C. Condensers. .冷凝器D. Air ejectors. 真空泵Questions 4- are based on paragraphs 3-6. 根据课文第3-7段回答问题4-8.4. The combined brine/air ejector creates a vacuum in the system in order to.喷射泵在系统里创造真空是为了_。答案.BA. increase the evaporation temperature of the feed water提高给水的蒸发温度B. decrease the evaporation temperature of the feed water.降低给水的蒸发温度C. decrease the temperature of the feed water降低给水的温度D. increase the condensing temperature of the feed water提高给水的冷凝温度5. The combined brine/air ejector is supplied by_.真空泵由_来提供。答案.BA. the fresh water pump淡水泵B. the ejector pump喷射泵C. the compressed air installation压缩空气装置D. the brine pump排盐泵6. The feed water to be distilled is taken from_被蒸馏的给水来自_。A. the sea cooling water outlet of the condenser冷凝器的海水冷却出口B. the fresh water cooling system.淡水冷却系统C. the sea cooling water inlet of the condenser冷凝器的海水冷却进口D. the sea suction strainer海水吸入滤器7. Drops of sea water removed by demister_被除雾器除去的海水滴_。答案BA. fall due to gravity into the evaporation section由于重力的作用落入蒸发器B. fall due to gravity into the brine sump由于重力的作用落入盐水池C. are removed by the fresh water pump由淡水泵除去D. are directly discharged overboard直接排到舷外8. The fresh water produced is delivered to a tank by a_产生的淡水通过排入淡水柜。答案C.A. fresh water ejector淡水喷射泵B. separately installed fresh water pump独立安装的淡水泵C. built-in fresh water pump内置的淡水泵D. vacuum pump真空泵Questions 9-13 are based on paragraphs 7-8. 根据课文第8-9段回答问题9-13.9. Too low hot water flow，due to incorrectly adjusted by-pass valve will cause_.由于旁通阀调节不正确，加热水流量过低会导致_。答案.BA. high boiling temperature高蒸发温度B. low boiling temperature and a drop in fresh water production 低蒸发温度和产水量下降C. increase of salinity增加盐度D. salinity remains unchanged盐度保持不变10. The air valve installed on the upper part of the separator vessel_.蒸发器上部的空气阀_。答案BA. should be opened during vacuum creation procedure建立真空时应打开B. should be opened after stopping the plant .机器停用时应打开C. should remain closed all the time 一直保持关闭D. should be opened during the evaporation process蒸发过程中应该打开11. In order to obtain the specified flow of hot water，it is necessary to_.为了保持加热水流量稳定，很有必要_。答案.CA. close the hot water inlet valve关闭热水进口阀 B. close the hot water outlet valve关闭热水出口阀C. adjust the by-pass valve until the desired jacket water temperature difference is reached调节旁通阀直到理想的缸套水温度D. adjust the pressure within the pipe.调节管内的压力12. _, open the hot water inlet and outlet valves from the jacket cooling system._，打开缸套冷却水系统的进出口阀。答案;AA. When there is a minimum of 90 % vacuum 达到最低90%真空度时B. When there is a minimum of 40 % vacuum达到最低40%真空度时C. Before starting the ejector pump启动喷射泵前D. When stopping the fresh water generator.当停用造水机时13. After stopping the fresh water generator, all valves must be closed except_造水机停用后，所有的阀都必须关闭除了_。答案AA. the air valve.空气阀B. the valves on the suction side of the ejector pump喷射泵吸入端的阀件C. the valves on the discharge side of the ejector pump喷射泵排出端的阀件D. the overboard valve for combined air/brine ejector真空泵的舷外排出阀Task 2 Vocabulary and Structure任务2词汇与结构A. Technical Terms A.专业术语Translate the following into Chinese. 将下列词组译成汉语。1. fresh water generator闪发式造水机2. shell