【正文】 they should not be used for throttling service or in hightemperature or highpressure service. ? 58 Chapter 2. Valves Summary 2 ?Diaphragm valves use a flexible membrane to throttle sticky, viscous, or corrosive materials. ?A butterfly valve has a pivoting flowcontrol element shaped like a flat disc. ?Check valves are used to control flow direction and to prevent contamination of or damage to equipment. ?Relief valves automatically respond to sudden increases in pressure in liquid services. ?Safety valves do the same thing in gas services. The three major difference between a relief valve and a safety valve are liquid versus gas service, the pressure response time, and the larger exhaust port of the safety valve. Relief valves are designed to lift slowly, whereas safety valves tend to pop off. ?Actuators are devices in a control loop that automatically adjust the position of the valve stem on a control valve. ? 59 Chapter 2. Valves Summary 3 ?The packing should be inspected, and the gland nuts tightened evenly if a leak is found. ?On gate valves, stem threads exposed to weather need to be lubricated. ?Maintaining equipment is an important part of an operator’ s job. ?Valve stems should not be painted, and every effort should be made to keep them free of dirt and dust. ?Process technicians should not overtighten a gate valve to avoid damaging the seats. ?When the gate is on the bottom, a wrench should never be used to wedge ir closed. ? 60 完 Thank you for listening 61 謝 謝 ！ 62 謝謝觀看 /歡迎下載 BY FAITH I MEAN A VISION OF GOOD ONE CHERISHES AND THE ENTHUSIASM THAT PUSHES ONE TO SEEK ITS FULFILLMENT REGARDLESS OF OBSTACLES. BY FAITH I BY FAITH 。 ? large exhaust port. Relief valve is designed to lift slowly。 ? Opposite magic poles attract each other, like magic poles repel each other。 ? Don’ t hurt other person。 ? Try to understand important concept for this course。 Other separation systems。 Reaction systems。 Process diagrams。 Fired heaters (furnaces)。 Cooling towers。 Turbines and motors。 Pumps。 Valves。 ) 17 What’ s means“ Process” ? How many kinds of process are related to us? What’ s means“ Process Equipment” ? Six processes are closely related to our specialty: 6. Chemical process: (化學(xué)過程 ) It deals with synthesize, deposition process and equipment. (它涉及化學(xué)反應(yīng)，如：合成、分解等過程及設(shè)備。 15 What’ s means“ Process” ? How many kinds of process are related to us? What’ s means“ Process Equipment” ? Six processes are closely related to our specialty: 4. Momentum transfer process: (動量傳遞過程 ) It deals with size reduction and size enlargement process and equipment. (它涉及固體物料的粉碎、造粒等過程及設(shè)備。 What’ s means “Process Equipment”? 12 What’ s means “Process” ? How many kinds of processes are related to us? What’ s means “Process Equipment”? Six processes are closely related to our specialty: 1. Fluid dynamical process: (流體動力過程 ) It deals with pump(泵 ), pressor(壓縮機 ), ventilator(風(fēng)機 ), pipes and valves(管道和閥門等 ). 13 What’ s means “Process” ? How many kinds of process are related to us? What’ s means“ Process Equipment” ? Six processes are closely related to our specialty: 2. Heat transfer process: (熱量傳遞過程 ) It deals with heat transfer equipment. (它涉及熱量交換過程及設(shè)備，即：換熱器，熱交換器等 )。只有化工機械專業(yè)由于其不可替代的重要性而予以保留，但是更名為“過程裝備與控制工程”專業(yè)。 improving our teaching quality。 ── ? To devote our best for students。Process Technology ─Equipment and System 華東理工大學(xué)機械與動力工程學(xué)院 2023年 3月 7日 Introduction 雙語教學(xué)： Bilingual education 1 Teachers for the class： 潘家禎 教授 博士生導(dǎo)師 王正東 教授 博導(dǎo) 學(xué)院常務(wù)副院長 周紹萍 副教授 系主任 在讀博士 惠 虎 副教授 博士 王學(xué)生 副教授 博士 石 巖 講師 在讀博士 周先桃 博士后 2 Our Team： Qualified teachers。 Best team。 ? To fulfill the task better. Team work ── ? Teaching research。 ? Teachers can learn each other from other’s strong points to offset one’s weakness. Our objective ? Cooperate with students to fulfill this class satisfactory. ? To obtain more knowledge, to learn actively, to be successful. 3 Three transforms： ? From passive study to active study. ? From forcedfeeding method of teaching to heuristic edu