Lesson-14-Air-Conditioning-System

精品文档 1欢迎下载 Lesson 14 Air Conditioning System 船舶空调系统船舶空调系统 1 Ships travel the world and are therefore subject to various climatic conditions The crew of the ship must be provided with reasonable conditions in which to work regardless of the weather Temperature alone is not a sufficient measure of conditions acceptable to the human body Relative humidity in conjunction with temperature more truly determines the environment for human comfort Relative humidity expressed as a percentage is the ratio of the water vapor pressure in the air tested to the saturated vapor pressure of air at the same temperature 船舶航行于世界各地会遇到各种各样的气候条件 无论天气如何 都应给船员们都必须在 合适的环境中工作 温度不是满足人体舒适要求的单一条件 相对湿度结合温度更能确实 地决定环境的舒适度 相对湿度用百分比表示 指的是被测空气中的水蒸气压力与相同温 度下的饱和水蒸气压力之比 2 An air conditioning system aims to provide a comfortable working environment regardless of outside conditions Generally air conditioning systems fall into two main classes individual unit system in which each room contains its own small refrigeration plant and fan and air cooler and central systems where larger refrigeration machinery unit are installed and their output distributed about by a variety of means The heating ventilation and air conditioning system on a cargo ship is usually a simple direct expansion ducted system Three main types of central air conditioning system are in general use the single duct the twin duct and the single duct with reheat 2 空调装置的主要目的就是不管外界环境如何 都能提供一个舒适的工作环境 总的来说 空调装置分成两种类型 一种是各自独立单元系统 在这种系统里 每个房间都有自己的小 的制冷装置 风机和空冷器 另一种是中央空调系统 在这种系遨缸里 装有一个大的制冷 装置 其输出采用不同方法进行分配 在船舶 加热系统 通风装置和空调系统通常采用 一个简单的直接膨胀的风管系统 广泛采用的中央空调系统有 3 种类型 它们是单风管 双风管和带加热的单风管系统 3 The single duct system is widely used on cargo ships Several central units are used to distribute conditioned air to a number of cabins or spaces via a single pipe or duct In warm climates a mixture of fresh and re circulated air is cooled and dehumidified during its passage over the refrigeration unit In cold climates the air mixture is warmed and humidified either by steam hot water or electric heating elements The temperature and humidity of the air is controlled automatically at the central unit Within the conditioned space control is by variation of the volume flow of air 3 单风管系统广泛应用在货船上 由中央空调器通过单风管送风至各个舱室 气候暖和时 新风和回风在流经制冷装置时被冷却并除湿 气候寒冷时 混合空气由蒸汽 热水或电加 热器进行加热和加湿 空气的温度和湿度由中央空调器自动控制 各空调舱室内的控制可 精品文档 2欢迎下载 通过改变送风量来实现 4 The twin duct system provides increased flexibility and is mainly used on passenger ships 4 双风管系统可以提供更为灵活的调节 主要用于客船 5 The single duct with reheat system is used for vessels operating in mainly cool climates The central unit will cool and dehumidify or reheat and humidify the air as required by outside conditions In addition before discharge into the treated space a local reheating unit will heat the air if required depending upon the room thermostat setting 5 再热式单风管系统用于主要在寒冷海域航行的船舶 根据外界气候条件 中央空调器对 空气进行冷却和除湿 或预热和加湿 此外 在 空气 排到被处理空间之前 如果需要的 话会有一个局部再加热装置对空气进行加热 这取决于房间温控器的设定 6 The refrigeration system used in the central unit is shown in Fig 14 1 A direct expansion system is shown using a reciprocating compressor sea water cooled condenser and a thermostatically controlled regulating valve The air to be cooled passes over the evaporator or cooler The cooling effect of the unit may need to be reduced if there is no great demand and the hot gas bypass system provides this facility 6 图 14 1 所示为中央空调器的制冷系统 这是直接膨胀式制冷系统 基本部件包括往复式 压缩机 海水冷却的冷凝器和恒温控制的调节阀 空气流经蒸发器或冷却器被冷却 如果 制冷需要量不大 可通过热气旁通系统降低空调器的冷却效果 精品文档 3欢迎下载 7 The first essential in operating the air conditioning appliances throughout the ship is to have all thermostats correctly set and correctly functioning In extreme weather conditions either hot or cold control of the plant usually presents few difficulties The capacity of many installations is such that under tropical conditions nearly all control valves move to the fully open position Control difficulties arise in intermediate weather conditions when there is a call for only a small amount of cooling The worst case is when part of the ship say inboard cabins against the engine room requires cooling and other parts say exposed upper cabins require warming For this intermediate condition thermostats must be correctly set by trial and error The control problem is eased if the chilled brine or water of systems using chilled liquid circulation is held at about 13 C in the intermediate weather conditions and lowered progressively to about 5 C as tropical weather conditions are approached 7 在操作全船空调设备时最基本的是要正确地设置所有的温控器 还要使之正常运行 在 极端的天气条件下 无论是太冷还是太热 装置的控制一般不存在什么困难 在热带条件 下 许多装置工作能力需要将几乎所有的控制阀移至全开位置 在中等天气条件下 仅需 少量冷却时 便会产生控制困难 最复杂的情况是船上的部分区域 比如紧挨机舱的舱室 精品文档 4欢迎下载 需要冷气 而其他区域 比如暴露于上层的舱室则需要暖气 对这种中间状况 温度调节 器必须经反复试验设定 如果使用冷盐水 或水 等冷却液在系统内循环的话 这种控制上 的问题就会得到解决 在中等天气下循环冷却液的温度保持在 13 当靠近热带天气条件 时温度逐渐降低到 5 8 When air cooling is in use it is good practice to keep all portholes windows and doors shut A wise precaution for an engineer to take is to go through accommodation and public rooms periodically recording wet and dry bulb temperatures Keeping a log of these readings then serves to identify any malfunctioning of the installation as soon as it arises 8 空调制冷时 应当关闭所有舷窗和门窗 轮机员应定期巡视各个住舱和公用舱室 记录 干湿球温度 保留这些记录便能在装置出现任何失常时立即确定故障原因 9 The quantity of cooled air delivered by an air conditioning unit should balance the sum of quantity of air re circulated to the unit and the quantity mechanically exhausted The correct balance between supply and exhaust fans should be checked periodically Even with filters fitted ducts can become partially blocked and fan performance can fall off to upset the balance 9 由空调装置供给的冷风量应当等于回风量和机械排风量之和 应定期检查送风机和排风 机的风量平衡 即使带有滤器的管路也可能部分堵塞 使风机性能降低 破坏风量的平衡 10 Maintenance of the above systems will involve the usual checks on the running machinery and the cleaning of filters Air filters in the central units are usually washable but may be disposable The filters should be attended to as required depending upon the location of the ship 10 上述空调系统的维护包括定期检查运转机械和清洗滤器 中央空调器的空气滤器通常是 可以清洗的 但也可以是一次性的 应根据船舶的位置 按需要对滤器进行维护 11 n addition to normal mechanical attention such as lubrication of bearings and adjustment of fan belts and cleaning of motors careful greasing of linkages of automatic controls is necessary Cooled air ducts should be examined to see that the insulation vapour seal remains in good order If a plastic film vapour seal becomes damaged condensation forms within the film As well as making the insulation wet and ineffective the condensation may become serious enough to cause drips and damp patches on ceilings 11 除了日常的机械维护 像轴承的润滑 风扇皮带的调整 电机的清洁及自控装置连接部 分的细心涂油也是必要的 应检查冷却风道使汽封隔绝良好 如果塑料膜汽封受损 膜内 形成冷凝 除了使得隔绝材料变湿和不起作用外 冷凝严重的话会引起液滴和顶上的湿斑 B Multiple Choice选择题 Questions 1 3 are based on paragraph 1 根据课文第 1 段回答问题 1 3 1 determine s human comfort 1 决定了人体的舒适程度 答案 D A Temperature温度 精品文档 5欢迎下载 B Relative humidity相对湿度 C Neither A or B A 和 B 都不是 D Both A and B A 和 B 2 Which of the following functions is not one of the functions of air conditioner 2 下列哪项不是空调的功能之一 答案 B A Refreshing the air 空气换新 B Waking up 唤醒 C Adjusting the air humidity 调整空气湿度 D Adjusting the air temperature 调整空气温度 3 The ratio of the weight of moisture contained in the given volume of air to the weight of moisture that the same sample would hold if saturated is called the 3 给定体积的空气中所含水分的质量与相同样品中饱和状态下所含水分的重量的比值 叫 作 答案 B A absolute humidity绝对湿度 B relative humidity相对湿度 C specific humidity含湿量 D total humidity湿度 Questions 4 6 are based on paragraphs 2 5 根据课文第 2 5 段回答问题 4 6 4 For the single duct system in warm weather the air mixture is when passing over the refrigeration unit 4 温暖天气下的单管系统 当空气混合物流经制冷机组时 答案 C A cooled and humidified 被冷却和加湿 B warmed and dehumidified被加热和除湿 C cooled and dehumidified被冷却和除湿 D warmed and humidified被加热和加湿 5 The single duct system is used on the twin duct system is used on and the single duct with reheat system is used on 5 单风管系统用于 双风管系统用于 再热式单风管系统用于 答案 D passenger ships cargo ships ships that often navigate in cold weather ships that often navigate in tropical area 客船 货船 经常在寒冷气候下航行的船 经常在热带区域航行的船 A B C D 精品文档 6欢迎下载 6 A reheater in an air conditioning system functions to 6 空调系统中再热器的作用是 答案 D A control inlet air temperature控制进口空气温度 B control inlet air volume控制进口空气体积 C maintain relative humidity at 15 保持相对湿度在 15 D restore conditioned air temperature to a comfortable level维持经调 节的空气在舒适的状态 7 The control problem if the temperature of the systems is kept at 13 C in the intermediate weather conditions 7 如果在中等天气条件下 系统温度保持在 13 则控制问题 答案 B A becomes more difficult变得更困难 B is eased缓解 C is increased增加 D remains the same不变 8 The most complex problem that happens in the control system is under weather condition 8 控制系统中最复杂的问题是处于 天气条件下 答案 D A extreme cold极冷 B extreme hot极热 C tropical热带 D intermediate中等 9 When air cooling is operating we should do all the following except 9 当进行空气冷却时 我们应该做好以下事情 除了 答案 A A keep all portholes windows and doors open保持所有的舷窗 门窗打开 B go and check accommodation and public rooms periodically定期检查住 舱和公用舱室 C record wet and dry bulb temperatures记录干湿球温度 D keep a log of relevant readings保留相关记录的日志 10 In the sentence The quantity of cooled air delivered by an air conditioning unit should balance the sum of quantity of air re circulated to the unit and the quantity mechanically exhausted the underlined word unit refers to 10 在句子 由空调装置供给的冷风量应当等于机组的回风量和机械排风量之和 中画线 词 机组 指 答案 A A air conditioning unit空调装置 B refrigeration unit制冷装置 C supply fans进气扇 D exhaust fans排气扇 11 Keeping a log of these readings then serves to identify any 精品文档 7欢迎下载 malfunctioning of the installation as soon as it 11 保留这些记录以便在装置 故障时用来确认故障原因 答案 D A rises上升 B raises增加 C is raised被举起 D arises出现 12 What routine work should be done to the linkages of automatic controls 12 对于自动控制机构的日常工作要做到哪些 答案 D A To remove and clean them 移动然后清洁它们 B To adjust them from time to time 不断调整它们 C To carefully lubricate them 对其进行小合润滑 D To carefully grease them 对其进行小心涂油 13 What harm will condensation formed within the plastic film do 13 在塑料薄膜内形成凝结有什么危害 答案 D A Making the insulation wet 绝缘受潮 B Making the insulation out of funtion 绝缘失效 C Causing damp patches on ceilings 顶上有湿斑 D All of the above 以上全部 Task 2 Vocabulary and Structure 任务 2 词汇与结构 A Technical Terms专业术语 Translate the following into Chinese 将下列词组译成汉语 1 air conditioning system空调系统 2 relative humidity相对湿度 3 re circulated air回