《制冷与空调专业英语第2版 教学课件 ppt 作者 林慧珠 主编 3-1》由会员分享，可在线阅读，更多相关《制冷与空调专业英语第2版 教学课件 ppt 作者 林慧珠 主编 3-1（20页珍藏版）》请在金锄头文库上搜索。
1、制冷空调专业英语,Unit Three,Lesson 9 Control Valves Lesson 10 Liquid Pump Lesson 11 The Reciprocating Compressor Lesson 12 Heat Exchanger,New Words & Expressions Text Notes to the Text Exercise,Lesson 9 Control Valves,New Words & Expressions,Lesson 9,科技地,component n. ;adj.,成分，组成的, 构成的,role n.,角色, 任务,accordi
2、ng to v.,依照,regulatory adj.,调整的,control performance,控制性能,particularly adv.,独特地, 显著地,sensitivity n.,敏感, 灵敏(度), 灵敏性,特性, 表示特性的, 典型的,characteristic n.;adj.,linearity n.,线性, 直线性,technologically adv.,Lesson 9,New Words & Expressions:,蒙乃尔铜-镍合金,microprocessor n.,微处理器,valve plug,阀塞,detachable adj.,可分开的, 可分离的
3、, 可分遣的,adjustable adj.,可调整的,stem n.;v.,茎, 干, 词干, 阻止,erosion n.,腐蚀, 侵蚀,corrosion n.,侵蚀, 腐蚀状态,stainless steel,不锈钢,guarantee n.;vt.,保证, 保证书，保证, 担保,Monel n.,Lesson 9,New Words & Expressions:,孔, 口,Hastelloy n.,哈司特镍合金, 镍基合金,Stellite n.,钨铬钴合金, 硬合金,Teflon n.,特氟纶，聚四氟乙烯（商标名称）,Graphite n.,石墨,orifice n.,Text,Co
4、ntrol valves are essential elements in the control of many industrial processes. A valve is a power component whose role is to regulate a flow of liquid in pipes according to the value of what is being measured (a level, a pressure, a temperature, a pH, etc.). 1 This flow often constitutes the contr
5、ol variable of the regulatory loop. Control performance - and particularly its sensitivity and linearity - is, therefore largely dependent upon the type and characteristics of the valve fitted. 2,控制阀门是许多工业过程必不可少的元件。阀门是动力元件，它的作用是根据所测的值（液位、压力、温度、PH值等）来调节管内液体的流量。这种流体通常构成控制回路的控制变量。控制性能-特别是它的灵敏度和线性-很大程度上
6、取决于所安装阀门的类型和特点。,Lesson 9,Text:,The choice of valve may affect the dimensioning of the process itself and that is why the choice is important. 3 Emphasis will be placed on determination of the flow evolution curve line with respect to the valve control. The linearity of this curve depends on the proc
7、ess itself and affects control performance. Linearity is difficult to obtain technologically, although the problem can sometimes be overcome by using a microprocessor.,Lesson 9,阀门的选择还会影响到整个过程的计算，这也是阀门的选择重要的原因。对于控制阀重点是确定其流量变化曲线。该曲线的线性取决于过程本身并影响其控制性能。从技术上很难获得线性曲线，虽然通过微处理器有时可以解决这个问题。,Text:,Construction
8、 of a Valve ACTUATOR The mechanism which converts the controller signal (from the regulator) into the motion which positions the valve plug. BODY Contains one or more seats or parts through which the fluid passes. TRIM Comprises the detachable parts of thevalve which are in contact with the fluid.,L
9、esson 9,阀门的构造： 执行器 将控制信号转化为确定阀塞位置运动的机械装置 主体 包括一个或多个零件，流体从中流过 附属装置 包括与流体接触的阀体的可拆开部件。,Text:,A control valve is an opening with an adjustable area. A stem driven by an actuator positions a plug which modifies the opening section of the valve.4 This progressive positioning makes possible the control of
10、the flow passing through the valve.,Lesson 9,一个控制阀就是一个可调节面积的通道。执行器驱动的阀干装有阀塞，阀塞改变阀门的开度，通过控制阀门的开度来控制通过阀门的流体。,Text:,The various components of a valve body are given below (for a double port valve)（Fig9-2）. As the body and the trim are the parts of the valve which are exposed to the fluid they must be r
11、esistant to erosion and corrosion.5 Different manufacturers suggest different materials according to the nature of the fluid, e.g. bronze, stainless steel, special alloys (Monel, Hastelloy. Stellite).,Lesson 9,阀体的不同组成部分如图9-2所示。因为阀体和阀门的其他装置是与流体接触的，所以它们应该能防腐。不同的制造商根据流体的性质建议使用不同的材料，如青铜、不锈钢、特殊金属（镍合金，哈司特
12、镍合金，钨铬钴合金）。,Text:,The same applies to the packing which guarantees that the stem part of the valve body is sealed.6 Two types of packing are most commonly used - Teflon and Graphite, depending on the nature of the fluid. An orifice in the bonnet allows for lubrication of the packing.,Lesson 9,对填料同样要
13、求防腐以确保阀体密封。常用的填料有两类特氟纶和石墨依据流体的状况来选择。阀帽上有一个供加润滑油的孔。,Notes to the Text,Lesson 9,Notes to the Text,1.A valve is a power component whose role is to regulate a flow of liquid in pipes according to the value of what is being measured.,Lesson 9,这是一个主从复合句，A valve is a power component后面部分为定语从句，修饰component。在定
14、语从句中是分词短语做状语，其中的what 从句是介词of的宾语。,Notes to the Text,2.Control performance - and particularly its sensitivity and linearity - is, therefore largely dependent upon the type and characteristics of the valve fitted.,Lesson 9,这是一个单句，Control performance - and particularly its sensitivity and linearity是主语部分
15、，后面的部分是表语部分。,Notes to the Text,3.The choice of valve may affect the dimensioning of the process itself and that is why the choice is important.,Lesson 9,句中dimensioning 意为“计算(指明设备布置的)连系尺寸， 定尺寸”， the dimensioning of the process可译为“确定系统的尺寸”。 在句中that指前面“阀门的选择可以影响确定系统的尺寸”这句话，而关系副词 why引导的从句在句中作表语。 affect意
16、为“影响，使他物发生变化，（使）感动”。 例如： Smoking affects health. 吸烟影响健康。 deeply affected by the news 深深被这消息所感动。,Notes to the Text,4.A stem driven by an actuator positions a plug which modifies the opening section of the valve,Lesson 9,在句中A stem是主语， driven by an actuator是过去分词短语作定语修饰stem ，positions是谓语， a plug是宾语 ，which modifies the opening section of the valve是定语从句修饰plug。,Notes to the Text,5.As the body and the trim are the parts of the valve which are exposed to the fluid they must
