Lesson-7-Starting-Air-System

精品文档 1欢迎下载 Lesson 7 Starting Air System 第 7 课 起动空气系统 1 Diesel engines are started by supplying compressed air into the cylinders in the appropriate sequence for the required direction A supply of compressed air is stored in air reservoirs or bottles or receivers at pressures about 30 or 40 bar ready for immediate use Up to 12 starts are possible with the stored quantity of compressed air The starting air system usually has interlocks to prevent starting if anything is not in order 柴油机是按所需方向 以适当顺序向各缸通入压缩空气起动的 所供压缩空气以 30 40bar 的压力存于气罐或气瓶内 随时可用 所储存的压缩空气量可进行多达 12 次的起动 起 动空气系统通常装有连锁装置 若其他设备没准备好 则不允许柴油机起动 2 Compressed air is supplied by air compressors to the air receivers The compressed air is then supplied by a large bore pipe to a remote operating non return or automatic valve and then to the cylinder air start valve Opening of the cylinder air start valve will admit compressed air into the cylinder The opening of the cylinder valve and the remote operating valve is controlled by a pilot air system Each cylinder air start valve is opened when the piston is just past TDC and closed just before the exhaust valve opens There is always more than one air start valve open which ensures that the engine will start in any position 压缩空气由空压机提供给空气瓶 压缩空气通过大口径管道进入遥控操作的止回阀或自动 阀 进而到达气缸起动阀 气缸起动阀开启 空气进入气缸 气缸起动阀及自动遥控阀由 控制空气系统控制 每个气缸起动阀在 活塞 经过上止点后立即开启 在排气口适当开启 前关闭 通常至少有一个及以上的空气启动阀处于开启状态 来确保主机能够在任何位置 进行启动 3 The pilot air is drawn from the large pipe and passes to a pilot air control valve which s operated by the engine air start lever When the air start lever is operated a supply of pilot air enables the remote valve to open Pilot air for the appropriate direction of 精品文档 2欢迎下载 operation is also supplied to an air distributor This device is usually driven by the engine camshaft and supplies pilot air to the control cylinders of the cylinder air start valves The pilot air is then supplied in the appropriate sequence for the direction of operation required The cylinder air start valves are held closed by springs when not in use and opened by the pilot air enabling the compressed air direct from the receivers to enter the engine cylinder Starting air is shut off from the engine as soon as sufficient starting speed has been reached fuel is then applied and the engine speed increased 控制空气来自主空气管并通入由柴油机起动操纵杆控制的起动控制阀 当操作起动手柄时 控制空气使控制导阀手动开启或 当驾驶台安装控制系统时 靠气动液压缸开启 控制空气 也通入空气分配器 空气分配器通常由柴油机凸轮轴驱动 它将控制空气通入气缸起动阀 此控制空气按所需运转方向以恰当的顺序通入 当不用气缸起动阀时靠弹簧保持关闭 当 它由控制空气打开时 压缩空气便直接从空气瓶进入气缸 一旦达到足够的启动转速 主 机将切断启动空气 供入燃油使主机的转速增加 4 An interlock in the remote operating valve line stops the valve opening when the engine turning gear is engaged The remote operating valve prevents the return of air which has been further compressed by the engine into the system 遥控阀管线中的连锁装置在盘车机没脱开时 可防止阀开启 遥控阀可防止发动机 活塞 进一步压缩的空气回流进人 空气 系统 5 A main engine must be capable of starting from any position and it is normal to have starting valves in each cylinder Multi cylinder Vee type engines may only require starting valves to be fitted to one bank of cylinders 主机必须可以从任何的曲轴位置都能启动 通常每缸都有启动阀 多缸 V 型柴油机可能只 儒要在单列气缸上安装启动阀 6 Air start explosions occur during a start when oil which can accumulate in the air start receivers or on the surface of the start air lines becomes entrained with high pressure air in the air start manifold and is ignited Regular maintenance work should be done and safety precautions should be taken to prevent such an occurrence 当聚集在启动空气瓶或启动空气管路表面的油与启动空气主管的高压空气混合并点燃时 启动期间就会发生爆炸 应当定期维护并采取安全预防措施防止此类事故发生 7 Lubricating oil from the compressor will under normal operation pass along the air lines and deposit on them In the event of a cylinder air starting valve leaking hot gases would pass into the air pipes and ignite the lubricating oil Checks must be made that cylinder starting air valves do not leak These can be carried out while the engine is running by feeling the temperature of the air pipe adjacent to the valve If starting air is supplied to the engine this would further feed the fire and could lead to an explosion in the pipelines In order to prevent such an occurrence 精品文档 3欢迎下载 cylinder starting valves should be properly maintained and the pipelines regularly drained Also oil discharged from compressors should be kept to a minimum by careful maintenance 滑油从压缩机出来流经空气管路 并沉积在内 在气缸起动阀万一泄漏时 高温燃气便进 入空气管 点燃滑油 此时 如果起动空气通入柴油机 将加剧燃烧 导致空气管路爆炸 为了防止此类事故的发生 气缸起动阀应妥善保养并对管路定期放残 同时 应通过细心 保养 使空压机排出的油保持在最小值 8 In an attempt to reduce the effects of an explosion flame traps relief valves and bursting caps or discs are fitted to the pipelines In addition an isolating non return valve is fitted to the system The loss of cooling water from an air compressor could lead to an overheated air discharge and possibly an explosion in the pipelines leading to the air reservoir A high temperature alarm or a fusible plug which will melt is used to guard against this possibility 为尽量减小爆炸的影响 管系内需安装阻焰器 安全阀 防爆帽或防爆片 此外 系统内 还要安装一个独立的止回阀 自动阀 以防压缩空气进一步进入系统 空压机冷却水不足会 导致排出的空气过热 并可能使通向空气瓶的管路发生爆炸 用高温报警器和易熔塞即可 预防此类可能发生的事故 精品文档 4欢迎下载 B Multiple ChoiceB 选择题 Questions 1 5 are based on paragraphs 1 5 根据课文第 1 5 段回答问题 1 5 1 Diesel engines are started by supplying into the cylinders in the appropriate sequence for the required direction 柴油机是通过把 以适当的顺序按照所需方向通人各缸启动的 答素 A A compressed air压缩空气 B pressed air 表述不正确 C compressing air 因要表示被动和完成的动作 故不能用现在分词 compressing D pilot air控制空气 2 in what position the engine stops there will always be at least one of the cylinders with its starting air valve open to admit compressed air to start the engine 主机在什么位置停车 至少有一个缸的启 动空气阀打开 允许压缩空气进人气缸启动主机 答案 D A Because因为 B Owning to因为 C For因为 D No matter无论 3 Clean dry compressed air at starting pressure 30 bar is stored and supplied to the system from 干净 干燥的压缩空气启动 压力 30 bar 被储存在 里 提供给系统 答案 A A air reservoirs空气瓶 B air distributors空气分配器 C cylinders气缸 D scavenging air box扫气箱 4 supplies pilot air to control the cylinder air start valves 提供控制空气到气缸启动空气阀的控制缸 答案 C A An air compressor空压机 B An indicator cock示功阀 C An air distributor 空气分配器 D A safety valve 安全阀 BD 5 When the is operated a supply of pilot air enables the remote valve to open 当操作时 控制空气使遥控阀开启 答案 B A distributor分配器 B air start lever启动空气操纵杆 C turning gear盘车机 D air valve空气阀 6 The starting air system usually has to prevent starting if anything is not in order 启动空气系统里通常带有 以便在异常情况下防止发动 机启动 答案 B A isolators隔离器 精品文档 5欢迎下载 B interlocks连锁装置 C tripping devices跳闸装置 D valve spring阀弹簧 7 engines may only require starting valves to be fitted to one bank of cylinders 柴油机可能只需要在单列气缸上安装启动阀 答素 C A Single cylinder Vee type单缸 V 型 B V IN line直列 C Multi cylinder Vee type多缸 V 型 D Any of the above上述任何一种 Questions 8 10 are based on paragraphs 6 8 根据课文第 6 8 段回答问题 8 10 8 Which of the following precautions should be taken to avoid an explosion in the pipelines 下列哪一预防措施可以防止管路发生爆炸 答素 D A Cylinder starting valves should be properly maintained 气缸启动阀应妥善保养 B The pipelines regularly drained 管路应定期放残 C Oil discharged from compressors should be kept to a minimum 从空压机排出的滑油量保持最少 D All of the above 以上全部 9 A high temperature alarm or which will mett is used to guard against the explosion of compressor air pipelines 高温警报或者可以熔化的用于防止压缩空气管路发生爆炸 答素 C A a flame trap火焰挡板 B a relief valve安全阀 C a fusible plug 易熔塞 D a bursting cap 防爆帽 10 Checks must be made that cylinder starting air valves do not leak These can be carried out while the engine is running adjacent to the valve 必须检查气缸启动阀是否泄漏 当主机正在运行时 可以气缸启动阀附近的 来进行检查 答案 C A by applying soap solution on the air pipe 通过在 空气管路上涂抹肥皂液 B by watching if there is bubble on the air pipe 通过感觉 空气管路的温度 C by feeling the temperature of the air pipe 通过观察 空气管路上是否有气泡 D by listening to the leaking sound emitting from the air pipe 通过听 空气管路发出的漏气声 Task 2 Vocabulary and Structure 任务 2 词汇与结构 A Technical Terms A 专业术语 精品文档 6欢迎下载 Translate the following into Chinese 将下列词组译成汉语 1 压缩空气 2 气瓶 3 控制空气 4 空气分配器 5 定时阀 6 阻焰器 7 安全阀 8 易熔塞 1 compressed air 2 air reservoir 3 pilot air 4 air distributor 5 timing valve 6 flame trap 7 relief valve 8 fusible plug B 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 meltisolateenablerequireleverescapedetect 1 Diesel engines are started by supplying compressed air into the cylinders in the appropriate sequence for the direction 1 required 柴油机是通过把压缩空气以适当的顺序按照所需方向通人各缸启动的 2 A high temperature alarm or a fusible plug which will is used to guard against this possibility 2 melt 高温报警器或者能够熔化的易熔塞即可预防此类可能发生的事故 3 Pressure will escape into the cylinder of any leaking air valve and this can be by listening at the open indicator cock 3 detected 压力会通过泄漏的气阀进人气缸 以上情况可以通过倾听打开的示功旋塞来检查 4 When the air start lever is operated a supply