Lesson-9-Marine-Boilers
高中英语选修9课件：Unit 2Sailing the Oceans597张 含解析 精品
the crowd.他们在人群中坚难行进。 navigation n. 航海，航行 navigational adj. 航海的，航行的
2)Using nature navigators could keep alongside thec_o_a_s_tl_i_n_e, use such
celestial bodies as North Star to ___p_lo_t__ their positions, as the sun overhead to n__a_v_ig_a_t_e by, as clouds
James Cook
• 1728年出生在英国北部的一个村庄。 10多岁时他第一次随船出海。他于 1775年加入皇家海军，此后成为了 一名航海和制图专家。1768年，库 克受命担任英国皇家海军太平洋考 察队队长。在其后的10年间，他带 领考察队进行了3次史诗般的航行， 足迹遍及未知的太平洋，揭开了地 球上最大水域的地理秘密。
3.What does seaweed look like when it is near land?
4.When did seaman use fog to help identify the posision of a stream or river?
1.How many skills are mentioned to help the navigators explore the seas?
show the way. Fog could help identify the _p_o_s_it_io_n_ of a stream or
三年级上册英语-Lesson 9 一起来学习 科普版
red cherry
士兵们和军官注意听着，开始注视周围的灌木丛和挂在道旁的白桦树枝。他们发现就在很近很近的地方，有个孩子坐在河岸边上，耷拉着两条腿。他光着头，穿一件颜色跟树叶差不多的 绿上衣，手里拿着一块木头，不知在削什么。 四年级语文下册《语文园地七》的学习目标是写自己敬佩的一个人，内容具体，语句通顺，认真修改。小编在此整理了四年级语文下册《语文园地七》，供大家参阅，希望大家在阅读过 程中有所收获! 四年级语文下册《将心比心》课文原文
colouபைடு நூலகம்ful world
See You！
询问他人“你最喜欢的颜色是什么”的句型是： What’s your favourite colour? My favourite colour is________.
我是小小记者： 以小组为单位，一人 当小记者采访其他同学，利
用“What’s your favourite colour?“问，“My favourite colour is...”来回答。
Let’s chant
What’s your favourite colour? 让我们一起唱
What’s your favourite letter? 起来吧！ I love every colour. I love every letter.
Oh, it's a yellow A.
And it’s a green Z.
三年级（上册）
Lesson 9 一起来学习
unit 9
Warming up: Let’s study together.
favourite
blue sea
orange orange
本组教材均为写人佳作，从科学家、艺术家、残疾人到普通农民，在追求成功的过程中，都闪烁着执著专注、坚持不懈的精神光辉。安排这次口语交际的训练，一是让学生继续学习这样 的品质;二是提高学生的口语表达能力。 本次口语交际的重点是把书的有关内容向大家介绍明白、清楚。教学中可参考以下几点： 6、文中某句话有什么含义?或告诉我们什么深刻的道理?请说说你的理解。 这种问题的回答不是简单地从文中寻找现成的句子就可以解决的，这需要我们的同学平时多读多看多积累 ，多看并记住一些富有哲理性的名言警句，这样才能真正地理解文章的意思，丰富回答内容，用自己的语言把自己对文章的理解准确地表达出来。 3、要注意习作赏析和评价：
六年级上册英语说课稿-《Lesson 9 Mr. Wood Teaches a Science Le
六年级上册英语说课稿 - Lesson 9 Mr. Wood Teaches aScience Lesson | 冀教版一、教学目标1.能够听懂并理解文章中的科学知识，如金属的导电性。
2.能够运用文章中的单词和短语，进行听、说、读、写等多方面的语言训练。
3.能够在课堂上积极参与，和同学们一起完成课堂活动。
二、教学重点1.掌握文章中涉及的科学知识点。
2.熟练掌握文章中的单词和短语，并能够使用它们进行语言训练。
三、教学难点1.对于金属导电性的概念理解和运用。
2.对于较为复杂的语言结构的熟练掌握。
四、教学内容1.针对学生已有的语言知识，引导他们理解文章中的重要信息。
2.尝试使用多样化的教学方法，以确保学生在课堂中的积极性和学习效果。
3.鼓励学生在课堂上积极参与，与同学一起完成课堂活动。
五、教学步骤（一）Classroom English首先，我们需要通过提示学生，使他们准备好听英语，学习英语。
在课堂的一开始，我们可以通过礼貌的提醒，鼓励学生准备迎接课堂的挑战。
（二）Warm-up其次，我们需要对学生进行一些热身活动，以激发他们的兴趣。
比如，可以让他们回答一些与科学有关的问题，如什么是金属导电性，等等。
（三）Teaching接下来，我们将逐步介绍文章中的重要知识点，并通过生动的图片或实际场景，使学生更好地了解和理解。
首先，我们将介绍金属导电性这个概念。
在此之前，我们可以展示一些装有金属的电器，如灯泡或电风扇，以引起学生的兴趣。
接下来，我们可以通过示范，演示金属在电路中的运作方式，以便更好地向学生传达这个概念。
接着，我们将学习文章中的单词和短语。
我们会发现，这些单词和短语都与金属概念密切相关，如电线、电路、电源等等。
教师可以引导学生分类记忆这些单词和短语，并通过听、说、读、写等多样化的方式，进行语言训练。
（四）Practice最后，我们会安排各种活动，以促进学生对所学知识的掌握。
例如，我们可以组织小组活动，让学生们讨论金属导电性的应用，或者进行词汇测试等等。
高级值班机工目录
高级值班机工业务目录第一篇机工业务第一章轮机工程第一节轮机安全值班第二节主推进动力装置的操作及运行管理第三节辅助机械的操作及运行管理第四节燃油的管理第五节其他设备的安全操作与管理第二章船舶电气第一节电气设备的安全使用和操作第二节触电的原因和预防触电应采取的措施第三章维护与修理第一节轮机日常维护修理工作程序和注意事项第二节油漆、润滑和清洁材料与设备的使用第三节表面清理技术第四节废料安全处置第五节液压工具、测量仪器的应用与维护第四章船舶作业管理与人员管理第一节船用物料管理第二节船舶防污染第三节船舶防污染技术与设备第四节轮机部安全作业注意事项第二篇动力设备操作与金工工艺第五章动力设备操作第一节轮机工程实操项目一机舱监视与报警系统的使用操作实操项目二发电柴油机故障应急操作实操项目三失电应急操作实操项目四船舶主柴油机备车、机动操纵与完车管理实操项目五船舶主柴油机定速后的运行管理实操项目六燃油加装时的操作与管理实操项目七燃油驳运时的操作与管理实操项目八舱底水系统的操作与运行管理实操项目九压载水系统的操作与运行管理实操项目十液压甲板机械的启动与停用实操项目十一液压系统的日常管理第二节电气、电子和控制工程实操项目十二发电机手动准同步并车、并联运行发电机组的负荷转移及分配、发电机组的解列第三节维护与修理实操项目十三通用工具实操项目十四专用工具实操项目十五量具第四节防污染设备实操项目十六油水分离器的操作与管理实操项目十七生活污水处理装置的操作和运行管理实操项目十八焚烧炉的操作和运行管理第六章金工工艺第一节车工工艺实操项目一卡盘、量具、刻度盘的使用以及刀具的磨制、车刀安装实操项目二车削台阶轴实操项目三车削锥体实操项目四车削螺纹柱第二节钳工工艺实操项目五钳工夹具、量具的使用实操项目六方块铁画线、钻孔、攻丝实操项目七方块铁錾切、锯割、锉削实操项目八螺栓拆卸与紧固实操项目九轴承的装卸实操项目十螺纹表面修复与断节螺栓的拆卸实操项目十一螺帽加工第三节电气焊工艺实操项目十二钢板平对接焊实操项目十三管子对接焊实操项目十四管板垂直角焊实操项目十五补焊实操项目十六钢板平对接焊实操项目十七管子对接焊实操项目十八气割附录1 MARPOL 73／78六个附则附录2 防污染法规参考文献高级值班机工英语目录Unit 1 Ship's Main Propulsion PlantLesson 1 A Brief Introduction to the Marine Diesel EnginesLesson 2 Diesel Engine ConstructionLesson 3 Main Diesel Engine Fuel Oil SystemLesson 4 Main Diesel Engine Lubricating SystemLesson 5 Main Diesel Engine Cooling Water SystemLesson 6 Main Diesel Engine Starting SystemUnit 2 Marine Auxiliary MachineryLesson 7 Marine BoilersLesson 8 Marine Pumps (A)Lesson 9 Marine Pollution Prevention EquipmentLesson 10 Oil SeparatorLesson 11 Deck Machinery (A)Unit 3 Marine Engineering ManagementLesson 12 Stand by Engine and Finished with EngineLesson 13 Safety Precaution on Working in Machinery SpaceLesson 14 Basic Knowledge of Fire and ExplosionLesson 15 Marine Emergency Arrangement and EquipmentLesson 16 BunkeringLesson 17 Lube Oil, Stores and Spare PartsUnit 4 International Conventions and RegulationsLesson 18 STCW Convention (A)Lesson 19 MARPOL Convention (A)Lesson 20 SOLAS Convention (A)Lesson 21 ISM Code (A)Lesson 22 ISPS Code (A)Lesson 23 ILO ConventionLesson 24 PSC Inspection (A)Unit 5 Watchkeeping and Engine Room LogbookLesson 25 Engine Room WatchkeepingLesson 26 Engine Room LogbookKey to ExercisesReferences高级值班机工英语听力与会话目录Unit 1 Daily EnglishLesson 1 Daily EnglishPart I Warm-up ActivitiesPart II Listening SkillsPart III Speaking SkillsLesson 2 Common terms on boardPart I Warm-up ActivitiesPart II Listening SkillsPart III Speaking SkillsUnit 2 Daily Engine Room BusinessLesson 3 Main Engine System OperationPart I Warm-up ActivitiesPart II Listening SkillsPart III Speaking SkillsLesson 4 Auxiliary Machinery Operation(I)Part I Warm-up ActivitiesPart II Listening SkillsPart III Speaking SkillsLesson 5 Auxiliary Machinery Operation(II)Part I Warm-up ActivitiesPart II Listening SkillsPart III Speaking SkillsLesson 6 Auxiliary Machinery Operation(III)Part I Warm-up ActivitiesPart II Listening SkillsPart III Speaking SkillsUnit 3 Communication with BridgeLesson 7 Stand by EnginePart I Warm-up ActivitiesPart II Listening SkillsPart III Speaking SkillsUnit 4 EmergenciesLesson 8 Emergency Situation(I)Part I Warm-up ActivitiesPart II Listening SkillsPart III Speaking SkillsLesson 9 Emergency Situation(II)Part I Warm-up ActivitiesPart II Listening SkillsPart III Speaking SkillsUnit 5 BunkeringLesson 10 BunkeringPart I Warm-up ActivitiesPart II Listening SkillsPart III Speaking SkillsUnit 6 PSC InspectionLesson 11 Port State Control InspectionPart I Warm-up ActivitiesPart II Listening SkillsPart III Speaking SkillsUnit 7 ISM/ISPS InspectionLesson 12 ISM/ISPS InspectionPart I Warm-up ActivitiesPart II Listening SkillsPart III Speaking SkillsUnit 8 Engine Room MaintenanceLesson 13 Engine Room MaintenancePart I Warm-up ActivitiesPart II Listening SkillsPart III Speaking SkillsKey to ExercisesAppendixReferences（注：可编辑下载，若有不当之处，请指正，谢谢!）。
建筑环境与设备工程专业(Heating Ventilation and Air Conditioning)英语教材
Lesson 9 Boiler System (锅炉系统)I. Text[1] Boiler are used to supply steam or hot water for heating, processing, or power purposes. This chapter is primarily concerned with a description of the low-pressure steam and hot-water space heating boiler used in the heating systems of residences and small buildings.[2]The basic construction of both low-pressure steam and hot-water space heating boiler fired by fossil fuels consists of an insulated steel jacket enclosing a lower chamber in which the combustion process takes place; and an upper chamber containing cast-iron sections or steel tubes in which water is heated or converted to steam for circulation through the pipes of the heating system.Steam and Hot Water Boiler Similarities and Differences [3]Steam and hot-water space heating boiler are very similar physically, but there are sone important differences:Steam boiler operate only about three-fourths full of water, whereas hot-water boiler operate completely filled with water. Steam boilers in residential steam heating systems operate at 13.79 kPa pressure or slightly more, where as residentialhot-water boilers operate at approximately six times that pressure.Steam boilers are equipped with a low-water cutoff device to protect the appliance from burning out if it should run out of water. Only large hot-water space heating boilers with a capacity exceeding 422.04 MJ/h are presently required by code to be equipped with low-water cutoffs. (Note: Many HV AC contractors who install the smaller residential hot-water boilers strongly recommend the addition of a low-water cutoff device to these appliances to prevent burn out if the boiler loses its water.) Steam boilers require makeup feed to replace water lost through evaporation and the production of steam during normal operation. Hot-water boilers can operate with little or on need for makeup water under the same normal operating conditions.[4]The design and construction of the lower chamber depends upon the type of fuel used to fire the boiler. It serves as a combustion chamber for coal-fired and oil-fired boilers and as a compartment for housing the gas burner assembly on gas-fired boiler. These gas burner assemblies are commonly designed for easy removal so that they can be periodically cleaned or serviced.[5]Oil burners are externally mounted with the burner nozzle extending into the combustion chamber. This is also true of gas conversion burners. Gas burner assemblies, on the other hand, are located inside the lower chamber of the boiler.[6]The cast-iron sections or stell tubes in the upper chamber of the boiler contain water that circulates through the pipes in the heating system in the form of either steam or hot water.The heat from the combustion process in the lower chamber of the boiler is transferred through the metal surface of the cast-iron sections or steel tubes to the water contained in them, causing a rise temperature. The amount of water contained in these passages is one of the ways in which steam boilers and hot-water space heating boilers are distinguished from one another.In hot-water space heating boilers these passages are completely filled with water; whereas in low-pressure steam boilers only the lower two-thirds are filled. In steam boilers the water is heated very rapidly, causing steam to form in the upper one-third. The steam, under pressure, rises through the supply pipes connected to the top section of the boiler.[7]A boiler jacket contains a number of different openings for pipe connections and the mounting of accessories. The numberand type of openings on a specific boiler jacket depends upon the type of boiler (i.e. Steam or hot water ). Among the different openings to be found on a boiler jacket are the flue connections, water feed (supply )connection, inspection and cleanout tapping, blow down tapping, relief valve tapping, control tapping, drain tapping, expansion tank tapping, and return tapping. These are also gas and oil burner connections Fig.1 illustrates the arrangement of tapping in a Weil-McLain oil-fires boiler.[8]Most (but not all ) of the controls on low-pressure steam and hot-water space heating boilers fired by the same fuel are similar in design and function, but there are exceptions. For example, a few boiler controls and fittings are designed to be specifically used on steam boilers; other are found only on hot-water space heating boilers.Boiler Rating Method[9]The construction of low-pressure steel and cast-iron heating boilers is governed by the requirements of the ASME Boiler and Pressure Vessel Code. This is a nationally recognized code used by boiler manufacturers, and any boiler used in a heating installation should clearly display the ASME stamp. State and local codes are usually patterned after the ASME Code.[10]The location of the identification symbols used by the ASME is specified by the code and determined by the type of boiler. For example, on a water-tube boiler, it appears in a head of the steam-outlet drum near and above the manhole opening. On vertical fire-tube boilers, the stamp bearing the identification symbol should appear on the shell above the fire door and handhole opening. Other types of boilers (e.g. Scotch marine and super heaters ) have their own specified location for the identification symbol stamp.[11] The ASME Boiler and Pressure Vessel Code applies only to boiler construction, specifically to maximum allowable working pressures, not to uts heating capacity. A number of different methods are used to rate the heating or operating capacity of a boiler, the boiler manufacturers have developed their own ratings, but these are generally used along with rating methods available from several professional and trade associations. [12]The Steel Boilers Institute no longer exists, but its SBI rating is still found on many existing stell boilers. The I=B=R (or IBR ) logo was created by the now defunct Institute of Boiler and Radiator Manufacturers to indicate the gross output (s) at 100 percent firing rate for most sectional cast-iron boilers. The I=B=R rating logo is now used by the Hydronic InstituteDivision of the Gas Appliance Manufacturers Association (GAMA).[13]The Mechanical Contractors Association of America has devised a method for rating boilers not covered by ether the SBI or I=B=R codes. Finally, fas-fired boilers are rated in accordance with methods developed by the American Gas Association.[14]Other rating logos appearing on boilers and in their installation and operation manuals are the Underwriters Laboratories, Inc. (UL) and the Underwriter’s Laboratories of Canada logos.[15]In terms of its heating capacity, the rating of a boiler can be expressed on square feet of equivalent direct radiation (EDR) or thousands of Btu/h. Sometimes a boiler horsepower rating is also given, but this is has proven to be misleading.[16]For steam boilers, 0.09 m2 of equivalent direct radiation (EDR) is equal to the emission of 253.21kJ/h. For a water boiler, 0.09 m2 of EDR is considered equal to the emission of 158.26kJ/h.[17]A boiler horsepower (bhp) os the evaporation of 15.66kg of water onto dry steam from and at 100℃. For rating purposes, 1 bhp is considered as the heat equivalent of 13.02㎡of steamradiation per hour. In some cases bhp ratings are oltained by dividing steam SBI ratings by 140.[18]A boiler is rated according to its operating or heating capacity, but this rating will vary in accordance with the type of load used as the basis for the rating. The three types of connected loads used to determine the rating of a boiler are:(1)Net load(2)Design load(3)Gross load[19]Net load refers to the actual connected load of the heat-emitting units in the steam or hot-water heating system. Design load includes the met-load rating plus an allowance for piping heat loss. Finally, gross load will equal the net load and the piping heat loss, plus an additional allowance for the pickup load.Boiler Heating Surface[20]The boiler heating surface (expressed in square feet ) is that portion of the surface of the heat transfer apparatus in contact with the fluid being heated on one side and the gas or refractory being cooled in the other side. The direct or radiant hearing surface is the surface against which the fire strikes. The surface that cones in contact with the hot gases is called the indirect irconvection surface.[21]The heating capacity of any boiler is influenced by the amount and arrangement of the heating surface and the temperature on either side, the arrangement if the heating surface refers to the ratio of the diameter if each passage to its length, as well as its contour (straight or curved ), cross-sectional shape, number of passes, and other design variables.Boiler Efficiency[22]the boiler efficiency is the ratio of the heat output to the caloric value of the fuel. Boiler efficiency is determined by various factors including the type of fuel used, the method of firing, and the control settings. For example, oil-and gas-fired boilers have boiler efficiencies ranging from 70 to 80 percent. A hand-fired boiler in which anthracite coal is used will have a boiler efficiency of 60 to 75 percent.Boiler energy Efficiency[23]Two government programs have been created within the last 20 years to rate the energy efficiency of different heating appliances such as furnaces, boilers, water heaters, and heat pumps. These two programs are (1) the annual fuel utilization capacity (AFUE) programs and (2) the Energy Star Certificationprogram.[24]Annual Fuel Utilization Capacity (AFUE). The energy efficiency of an oil-, gas-, or coal-fired boiler is measured by its annual fuel utilization capacity (AFUE). The AFUE reatings for boilers manufactured today are listed in the boiler manufacturer’s literature. Look for the EnerGuide emblem for the efficiency rating of that particular model. The higher the rating, the more efficient the boiler. The government has established a minimum rating foe boilers of 78 percent. Mid-efficiency boilers have AFUE ratings ranging from 78 to 80 percent. Higher-efficiency (condensing ) boilers have AFUE ratings ranging from 88 to 97 percent. Conventional ( noncondensing ) steam and hot-water space heating boilers have AFUE ratings of approximately 60 to 65 Percent.[25]Energy Star Certification. Energy Star os an energy performance rating system created in 1992 by U.S. Environmental Protection Agency (EPA) to identify and certify certain energy-efficient appliances. The goal is give special recognition to companies who manufacture products that help reduce greenhouse gas emissions. This voluntary labeling program was expanded by 1995 to include furnaces, boiler, heat pumps, and other HV AC equipment. Both the Energy Star labeland an AFUE rating are used to identify an energy-efficient appliance.Types of Boiler[26]The boiler used in low-pressure steam and hot-water space heating systems can be classified in a number of different ways. Some of the criteria used in classifying them are:(1)Construction material(2)Construction design(3)Boiler position(4)Number of passes of the hot gases(5)Length of travel of the hot gases(6)Type of heating surface(7)Type of fuel used[27]Most boilers are constructed of either cast iron or steel. A few are constructed from nonferrous materials such as aluminum. Cast-iron boilers generally display a greater resistance to the corrosive effects of water than steel ones do, but the degree of corrosion in steel boilers can be significantly reduced by chemically treating the water. [28]The heating core of many boilers is formed by joining together a series of cast-iron sections either horizontally (so-called pancake construction ) or vertically. In the horizontalcast-iron section design, the heating surface of each cast-iron section is exposed at right angles to the rising flue gases. The water travels in a zigzag path from section to section in a manner similar to the flow of water on a steel tube boiler. [29]Steel boilers may be classified with respect to the relative position of water and hot gases in the tubular heating surface. In fire-tube boilers, for example, the hot gases pass within the boiler tube while the water being heated circulates around them. In water-tube boilers, the reverse is true. Flexible steel tubes are used in some boilers for the circulation of the water around the heat rising from the fire.[30]A hot-water (hydronic) copper-fin tube operates on a different principle from the cast-iron and steel boilers. It is designed to transfer heat almost instantly to the water. Water flows across the boiler heat exchanger, picks up heat, and then moves through the pipes to the heat convectors, radiators, or panels.Note If the water stops flowing while the burner is still running, heat will build up until the water flashes into steam and damages the boiler. This condition is similar to dry firing in cast-iron and steek boilers. It can be avoided by installing a flow switch in the path of the water. The switch turns off the burner when the waterstops flowing.[31]Boilers can also be classified according to the number of passes made by the hot gases (e.g. One pass, two passes, and three passes). The length of travel of the hot gases is another method used for classifying boilers. The efficiency of a boiler heating surface depends, in part, upon the ratio of the cross-sectional area of the passage to its length.[32]Among the various fuels used to fire boilers are oil, gas ( natural and propane),coal, and coke. Conversion kits for converting a boiler from one gas to another are available from some manufacturers. Changing from coal (or coke ) to oil or gas can be accomplished by using conversion chambers and making certain other modifications.[33]Electricity can also be used to fire boilers. One advantage in using electric-fired boilers is that the draft provisions required by boilers using combustible fuels is not necessary. Unlike the boilers fired by fossil fuels (oil, gas, coal, etc.), electric boilers do not have an AFUE efficiency rating. They operate at almost 100 percent efficiency.[34]The classification criteria described above are selective and limited to the more common types in use. Considering the multiplicity of boiler types and designs available, it is extremelydifficult to establish a classification system suitable for all of them.。
lesson 16
There are many types of watertube boilers in general use on board ship and each manufacturer has a variety of designs to offer depending upon requirements. requirements.
These waterwall tubes are connected either to upper and headers(联箱 联箱) lower headers(联箱) or a lower header and the steam drum. drum.
Jimei university
Between the steam drum and the smaller water drum below, large numbers of smaller diameter generating tubes( 蒸 发管束) fitted. 发管束) are fitted.
Jimei university
and the water-tube boiler(水管 waterboiler(水管 锅炉) 锅炉) in which the water flows through the inside of the tubes while the hot furnace gases pass around the outside. outside.
Jimei university
A later development of waterwatertube boilers is the bent tube design. design.
大连海事大学成教教学日历
大连海事大学继续教育学院（函授）教学周历
版本：J 修改状态：0 DMU－4－095－1 编号：
注：每次完成单元测验后应将测验及完成的作业邮寄到学校。
函授站站长签字：
大连海事大学继续教育学院（函授）教学周历版本：J 修改状态：0 DMU－4－095－1 编号：
专业、层次、年级：轮机专科11级主讲教师：王辉
教材名称：《航海概论》（赵庆涛主编2010）
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大连海事大学继续教育学院（函授）教学周历
版本：J 修改状态：0 DMU－4－095－1 编号：
注：每次完成单元测验后应将测验及完成的作业邮寄到学校。
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六年级下册英语课堂课件-Lesson9Ihelpedadeafmantogethome.科普版(23
六年级下册英语课件-Lesson9 I helped a deaf man to get home . 科普版(23张)【PPT完美】
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六年级下册英语课件-Lesson9 I helped a deaf man to get home . 科普版(23张)【PPT完美】
六年级下册英语课件-Lesson9 I helped a deaf man to get home . 科普版(23张)【PPT完美】
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六年级下册英语课件-Lesson9 I helped a deaf man to get home . 科普版(23张)【PPT完美】
六年级下册英语课件-Lesson9 I helped a deaf man to get home . 科普版(23张)【PPT完美】 六年级下册英语课件-Lesson9 I helped a deaf man to get home . 科普版(23张)【PPT完美】
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六年级下册英语课件-Lesson9 I helped a deaf man to get home . 科普版(23张)【PPT完美】
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Lesson 9 Marine Boilers第9课船用锅炉1. Boilers are used on board ship for producing steam. This steam may be used for driving the main engines, when steam turbines are fitted, or for driving auxiliary machinery such as the windlass. There are two basic types of boiler in use in ships: the fire-tube boiler the （terms “smoke tube”and “donkey boiler”are also in use), and the water-tube boiler. Both are illustrated in Fig. 9-1船用锅炉用来产生蒸汽。
蒸汽在装有蒸汽轮机的船上可用于驱动主机，也可用于驱动辅助机械，如锚机。
船用锅炉有两种基本类型：火管锅炉（也使用“烟管锅炉”和“辅锅炉”这两个术语）和水管锅炉。
分别图示如下9-1。
2. Now if you look at the diagram of the fire-tube boiler you will see that it consists ofa cylindrical steel shell, which contains a furnace at the bottom. Two or more furnaces may be fitted, depending on the size of the boiler. The furnace is connected to a combustion chamber, situated in the middle part of the boiler. Leading from this combustion chamber to a smoke box are a large number of horizontal tubes. Some of these are used for supporting the middle section of the boiler and the combustion chamber. Connected to the smoke box are the uptakes for the waste gases. The furnace, the combustion chamber and the tubes are all surrounded by water.在火管锅炉的图中可以看到，它由一个圆筒形的钢外壳构成，其底部有炉膛。
根据锅炉的大小，可以安装两个或更多的炉膛。
炉膛和位于锅炉中间位置的燃烧室相通。
燃烧室和烟箱之间设有许多水平烟管。
一部分烟管用来支撑锅炉中部和燃烧室。
与烟箱相连的是废气的上升烟道。
炉膛、燃烧室和烟管都被水包围着。
3. The fire-tube boiler is usually of both riveted and welded construction. It is strong and is capable of operating with poor quality feed water. But there are more efficient types of boiler, which can generate more power; therefore fire-tube boilers are now mainly chosen for low-pressure steam production on vessels requiring steam for auxiliary purposes.火管锅炉一般为铆接和焊接结构，结构坚固，能够使用劣质给水工作。
但是，有些类型的锅炉效率更高，能够产生更大量的蒸汽；因此，苏格兰式锅炉(火管锅炉)现在主要为需要蒸汽驱动辅助机械的船舶提供低压蒸汽。
4. Water-tube boilers have replaced fire-tube boilers for generating high-pressure, high-temperature, high-capacity steam for main engines or cargo pump turbines. From the diagram you will see that they have a steam drum at the top, which is partly filledwith water, and water drums at a lower level. These drums are connected by banks of tubes, which also contain water. The furnace is located at the bottom and the whole system is contained in a fireproof casing. Downcomer tubes are placed outside the gas system to act as feeders to the water drums.水管锅炉已经取代了火管锅炉，产生高压高温大流量的蒸汽，以驱动主机或货油泵透平。
从图上可以看到，水管锅炉的顶部有一个汽鼓，部分注水；下部有多个水鼓。
汽鼓和水鼓由管束连接，管内有水。
炉膛位于底部，整个系统由耐火外壳包围。
下降管安装在燃气系统之外，用作水鼓的给水管。
5. Gases are heated in the furnace and pass upwards through the banks of tubes, transferring their heat to the water in the tubes. Because the steam drum provides a reservoir of relatively cool water, convection currents are set up causing the water to circulate round the system. The banks of tubes (generating tubes) offer a large surface area to the radiant heat of the furnace gases. This makes them very efficient. Superheaters are added to the system to increase its efficiency. These are located between the rows of tubes.在炉膛内加热的燃气向上通过管束，将热量传递给管内的水。
因为汽鼓里存储的水温度相对较低，系统内就形成对流，使水得以循环。
管束（蒸发管）提供了一个较大的炉膛燃气辐射受热面，使蒸发效率很高。
过热器加装到系统中，进一步提高了效率，它们一般设置在管排间。
6. Various valves and gauges are fitted to the boilers. Those attached directly to the pressure parts of the boiler are known as boiler mountings. The mountings usually found on a boiler are: safety valves, which are needed to protect the boiler against overpressure; a main s top valve in order to control the passage of steam to the engines; feed check valves to control the final entry of water into the boiler; water level indicators to show the level of water in the boiler; a blow down valve enables water to be blown down or emptied from the boiler; a scum valve enables the blowing down or removal of scum and impurities from the water surface and thermometers for showing the temperature inside the boiler. In order to be able t o blow away soot and the products of combustion from the tube surfaces, soot blowers are fitted which are operated by steam or compressed air. Salinometer valves are also fitted to allow samples of water to be drawn off for testing. Chemical dosing valves are also necessary so that chemicals can be added directly into the boiler锅炉上装有各种阀和测量仪表。
直接与锅炉压力部件相连的称为锅炉附件。
通常的锅炉附件有：防止锅炉超压的安全阀，控制通向发动机的蒸汽的主停汽阀，控制锅炉进水量的给水止回阀，显示锅炉水位的水位指示器，排出或放空锅炉水的下排污阀，排出或除去水面浮渣和杂质的上排污阀，以及显示锅炉内部温度的温度计。
为了吹除管壁上的烟灰和燃烧产物，安装了用蒸汽或压缩空气工作的吹灰器。
盐度计阀（取样阀）也安装在锅炉上，以便可以提取样水进行检测。
还需要安装投药阀，这样化学制剂就能直接加入锅炉中。