Lesson-6--Cooling-Water-System.doc

Lesson 6 Cooling Water System1.As a “heat engine”, heat energy is a source of power by which the diesel engine can be operated. But excessive heat will cause damage to the engine. It is therefore necessary to constantly cool the various components of the machinery so that the engine can work properly. Two relative cooling water systems are designed for this purpose, respectively termed fresh water cooling system and sea water system.作为一种热机, 热能是使柴油机运转的能源。但温度过高将引起柴油机的损坏。因此, 不断地冷却各种机械零件是必要的。只有这样, 柴油机才能很好地工作。为此设计了各个独立的冷却系统。分别称为淡水冷却系统和海水冷却系统。Fresh Water Cooling Systems淡水冷却系统2.Slow and medium speed engines use fresh water to circulate and cool the cylinder jackets and covers. The same system may also circulate exhaust valves and water cooled turbochargers if fitted.低速和中速柴油机使用淡水循环冷却缸套和缸盖。如果安装了的话，同样的系统也在排气阀以及水冷涡轮增压器中循环。3.In large, slow engines the cooling water pumps are independently driven and controlled. Pumps are arranged in duplicate, each being sufficient to operate the system alone while the other acts as standby. Pressure relief valves are fitted and alarms to give warning of pressure loss, high or low tank levels or excess temperature.在大型低速柴油机内，冷却水泵是单独驱动和控制的。泵是成对安装的，每个都足以单独在系统中操作，另一个作为备用。系统装有减压阀和警报器，在压力损失、高水位或低水位，或者温度过高时发出警报。 4.Fresh water coolers are circulated and cooled with sea water and have bypass valves. Pressure of the fresh water must exceed that of the sea water to prevent any possibility of sea water leakage into the system.淡水冷却器是由海水循环冷却的，配有旁通阀。淡水压力必须高于海水压力，以防海水泄漏到系统内。5.Fresh water may cause the deposit of scale on heated surfaces and although distilled water will prevent this, it may still cause pitting and erosion and become acidic with use. Corrosion inhibitors and alkaline agents are added to the system to protect metal surfaces.淡水可能引起受热面上沉积水垢。虽然蒸馏水可以防止这个问题，但也会引起点蚀和剥蚀，并会随着使用变为酸性。系统中要加人防蚀剂和碱剂，以保护金属表面。6.Chemical additives such as nitrite-borates may be used; they create a thin passive oxide surface layer on most metals. With this treatment, no zinc anodes are fitted; galvanized piping and all solder joints must also be avoided.可以使用化学添加剂，如亚硝酸盐硼酸盐类，它们可以在大多数金属表面形成一层惰性氧化物薄层。如有这种处理，不能安装锌阳极;也必须避免使用镀锌管路和锡焊接口。7.Fig. 6-1 shows line diagrams for fresh water cooling of cylinder jackets and pistons in a large two-stroke engine. These are in fact separate systems and only the jacket water cooling is required for engines which have oil-cooled pistons.图6-1展示的是大型二冲程柴油机中缸套和活塞的淡水冷却线路图。这些系统实际上是独立的系统，带有油冷活塞的柴油机只需要缸套冷却水系统。8.Jacket cooling water systems form a closed circuit. Water passing from the engine returns through a cooler to the pump suction and then back to the engine (the order between cooler and pump may be reversed in some systems). Provision has to be made for the expansion of the water due to the increase in temperature and due to small amounts of air which may enter the system and become entrained and for water make-up due to leakages. These are met by a head or expansion tank which is open to the atmosphere and placed at a higher level than any other point in the system so that the small changes in volume can be accommodated by changing the level of the free surface of the water in the tank.缸套冷却系统形成一个闭式回路。从发动机的水通过冷却器返回到泵的吸入端, 然后再回到发动机。必须为因水温的增加和空气的进入并滞留在系统内而产生膨胀以及补偿漏泄设置装置。这可由一小型水柜来实现。该柜直通大气, 且放且在比系统内任何点均高的位置, 以便补偿系统内容积的变化。通常在系统水泵的吸入端连接一高置水柜, 这样可以使空气吸入系统的机会减少。水柜的最小安装高度可基于保持热交换器中的淡水压力高于其中的海水压力。以确保万一发生内部漏泄时, 海水不能进入淡水系统。或者, 以在缸套内保持避免气蚀的最小压力为基准。9.The head tank is generally connected in to the system a t the pump suction, as this minimizes the chance of air being drawn into the system at the pump. The closed systems usually need vents if steam pockets or air locks are not to cause trouble. Vent pipes of small-bore tube are led from any local high point in the system t o the t op of the head tank for the release of air from the cooling water. A heater in the circuit facilitates warming of the engine prior to starting by circulating hot water. Alternatively, auxiliary engines fresh water systems may be coupled, to use waste heat from these for warming the main engine during stand-by periods. A fresh water generator may be added to use further waste heat.通常在系统水泵的吸入端连接一高置水柜, 这样可以使空气吸入系统的机会减少。水柜的最小安装高度可基于保持热交换器中的淡水压力高于其中的海水压力。以确保万一发生内部漏泄时, 海水不能进入淡水系统。或者, 以在缸套内保持避免气蚀的最小压力为基准。Fig. 6-1 Fresh water cooling systems10.The temperature of the water entering the engine jackets is regulated by means of a bypass across the jacket water cooler. The proportions of water passing through the cooler, or bypassing it are controlled by a three-way valve. The temperature is usually adjusted to maintain a constant outlet water temperature from the engine regardless of the load or speed or the temperature of the sea water.缸套冷却水的进机温度可通过缸套水冷却器的旁通调节。通过冷却器的水量或旁通量经三通阀调节。温度的调节通常是维持确定的离机出口温度, 而不考虑负荷、转速或海水温度。11.Piston cooling water system is also shown in Fig. 6-1. It is independent of the jacket system, allowing piston temperatures to be higher and preventing possible contamination of the jackets in the event of piston gland leakage passing lubricating oil to the system.活塞冷却水系统如图6-1.它独立于缸套冷却系统, 允许活塞温度高一些并防止万一活塞密封泄漏滑油进入系统引起可能的污染。12.Fuel valve cooling systems may be fitted as a separate fresh water system. A heater can be incorporated in these to warm fuel injectors before starting on heavy fuel.Sea Water Cooling System海水冷却系统13.The various cooling liquids which circulate the engine are themselves cooled by sea water. The usual arrangement uses individual coolers for lubricating oil, jacket water, and the piston cooling system, each cooler being circulated by sea water. Some modern ships use what is known as a central cooling system with only one large sea water circulated cooler. This cools a supply of fresh water which then circulates to the other individual coolers. With less equipment in contact with sea water the corrosion problems are much reduced in the system.在发动机内循环的各种冷却液自身被海水冷却。通常, 滑油、缸套和活塞冷却系统都使用独立的冷却器, 各冷却器通过海水循环冷却。有些现代船舶使用所谓的中央冷却系统, 仅有一个大型的海水循环冷却器冷却淡水, 其他各独立的冷却器则用淡水循环冷却。由于较少的设备与海水接触, 从而大大降低了因海水而引起的腐蚀。14.In a common sea water cooling system, from the sea suction one of a pair of sea water circulating pumps provides sea water which circulates the lubricating oil cooler, the jacket water cooler and the piston water cooler before discharging overboard. Another branch of sea water main provides sea water to directly cool the charge air (for a direct-drive two- stroke diesel).在通常的海水冷却系统中, 两台海水循环泵中的一个泵将海水从吸入口吸迸, 一路提供给滑油冷却器、缸套水冷却器及活塞水冷却器, 然后排出船外;另一路直接用来冷却增压空气(用于直接驱动式二冲程柴油机)。15.In an emergency situation, for example in the event of damage to a fresh water cooler or generator, the sea water pumps can be used to supply sea water to the fresh water cooling system, merely by removing the blind-flanges.在紧急情况下, 例如, 万一淡水冷却器或造水机出现损坏, 只需将盲板法兰卸去, 海水泵就能向淡水冷却系统供应海水。D.Multiple Choice B.选择题Questions 122 are based on paragraph 1. 根据课文第，段回答问题1 -21.As a “heat engine”, energy is a source of power by which the diesel engine can be operated.1.作为“热机”，_能是柴油机的能量源。答案CA.chemical .化学 B. mechanical机械C.heat 热 D. electrical电2.Two relative cooling water systems are designed for this purpose, respectively termed 为达到冷却目的，设计了两种相关的冷却水系统，分别称作_。答案;AA.fresh water cooling system and sea water system淡水冷却系统和海水冷却系统B.sea water cooling system and lubricating oil cooling system海水冷却系统和滑油冷却系统C.fresh water cooling system and lubricating oil cooling system淡水冷却系统和滑油冷却系统D.jacket cooling system and piston cooling system缸套冷却系统和活塞冷却系统Questions 3-11 are based on paragraphs 2-11.根据课文第2-11段回答问题3-1103.Pumps are arranged , each being sufficient to operate the system alone while the other acts as standby.泵是_安装的，每个都足以单独在系统中操作，另一个作为备用。答案.CA. in double (不是短语，应使用in duplicate) B. in triplicate一式三份C.in duplicate成对 D. in fourfold一式四份4.In the fresh water cooling system, pressure of the fresh water must be that of the sea water to prevent any possibility of sea water leakage into the system. 在淡水冷却系统中，淡水压力必须_海水压力，以防海水泄漏到系统内。答案:CA. lower than 低于 B. as high as一样高C.higher than 高于 D. high than语法错误)5.Chemical additives such as nitrite-borates may be used in fresh water system. With this treatment, no are fitted；galvanized piping and all solder joints must also be avoided. 可以使用化学添加剂，例如亚硝酸盐一硼酸盐被加人到淡水冷却系统中。如有这种处理，不能安装;也必须避免使用镀锌管路和锡焊接口。答案.AA.zinc anodes锌阳极B. chromium-plated parts镀铬部件C.copper parts铜制部件D. steel parts钢制部件6.Piston cooling water system is the jacket system, allowing piston temperatures to be higher and preventing possible contamination of the jackets in the event of piston gland leakage passing lubricating oil to the system. 活塞冷却水系统缸套冷却系统，允许活塞温度高一些，并防止万一活塞密封泄漏滑油进人系统引起可能的污染。答案;AA. independent of独立于B. connected to连接到C.dependent on依靠D. connected with与连接7.A closed fresh water cooling system is commonly used with marine diesel engines because the6 . 船用柴油机普遍采用闭式淡水冷却系统，因为_答案:AA.jacket water temperature is more easily controlled缸套水的温度较易控制B.need for water treatment is eliminated不需要水的处理C.cooling water temperature differential is greater冷却水温差较大D.cooling water pumps are directly reversible冷却水泵可直接换向8.Fresh water may cause the deposit of scale on heated surfaces and water will prevent this, it may still cause pitting and erosion and become with use. Corrosion inhibitors and agents are added protect metal surfaces. 淡水可能引起受热面_L沉积水垢。虽然蒸馏水可以防止这个问题，但也会引起点蚀和剥蚀，并会随着使用变为_。系统中要加人防蚀剂和_以保护金属表面。答案:AA.acidic/alkaline酸性/碱B. alkaline/acidic碱性/酸C.neutral/acidic中性/酸D. neutral/alkaline中性/碱9.The expansion tank in a diesel engine closed fresh water cooling system is located at 柴油机闭式淡水冷却系统中的膨胀柜位于_。o :AA.the highest point in the system系统的最高点B.the lowest point in the system系统的最低点C.the floor地板D.the plate level or near the tank top level底层或靠近柜子顶层10.There is in any water cooling system for a diesel engine allowing for expansion and water make-up in the system as well as air vent and chemicals addition. .在柴油机冷却系统中都有_，用来允许系统内水的膨胀、补水、放气、投药。答案;CA. a setting tank沉淀柜B. a service tank日用油柜C.a head tank膨胀柜D. an expansion joint膨胀接头11.Slow and medium speed engines use to circulate and cool the cylinder jackets and covers. 低速和中速柴油机使用_循环冷却缸套和缸盖答案:BA.sea water海水B. fresh water淡水C.cooling oil冷却油D. any of the above.上述任何一种Questions 12-14 are based on paragraphs 12-15. 根据课文第12 -15段回答问题12 -14012.The various cooling liquids which circulate the engine are themselves cooled by 在发动机内循环的各种各样的冷却液体本身被_冷却。答案:B A. fresh water淡水B. sea water海水C.lubricating oil滑油D. any of the above.上述任何一种13. sea water the corrosion problems are much reduced in the central cooling system. _海水，在中央冷却系统中，腐蚀问题大大减小了。答案;DA.Without less equipment in contact with由于没有较少的设备接触B.Because no equipment in contact with(语法结构错误)C.With fewer equipment in contact with(语法错误，equipment为不可数名词)D. With less equipment in contact with由于较少的设备接触14.In an emergency situation, for example in the event of damage to a fresh water cooler or generator, the sea water pumps can be used to supply to the fresh water. cooling system, merely by removing the blind-flanges.在紧急情况下，比如当淡水冷却器或造水机故障时，只需将盲板法兰卸去，海水泵就能向淡水冷却系统供应_。答案:AA. sea water海水B. fresh water淡水C.cooling oil冷却油D. any of the above上述任何一种Task 2 Vocabulary and Structure任务2词汇与结构A. Technical TermsA.专业术语Translate the following into Chinese. 将下列词组译成汉语。1减压阀 2旁通阀 3蒸馏水 4防蚀剂5副机 6闭路 7膨胀柜 8中央冷却系统1.pressure relief valve 2.bypass valve 3.distilled water 4.corrosion inhibitor 5.auxiliary engine 6.closed circuit 7.expansion tank 8.central cooling system D.Active Words.常用词Complete the following sentences by filling in the blanks with the words in the table. Change the form of the words if necessary.从框中选词完成句子，如有必要改变词的形式。coupleexceedventpressurizecirculategalvanizemaintain1. Slow and medium speed engines use fresh water to and cool the cylinder jackets and covers.1 .circulate 低速和中速柴油机使用淡水循环冷却缸套和缸盖。2.A head or expansion tank is placed at a reasonable height to allow and of