正做-专业英语(L11)

1、Part Mine Safety LESSON 11 Methods of Dust Control 教学内容教学内容 Introduction VentilationWater spraysDust collectors LESSON 11 Methods of Dust Control 教学目的教学目的 要求学生要求学生熟记专业词汇熟记专业词汇，达到，达到英文与中文相英文与中文相互熟练翻译互熟练翻译的程度的程度aerosol rsl Microflora ,maikrufl:r respiratory resprtri abrasion brein boring extraction lo

2、ngwall shearer aerosol 浮质浮质(气体中的悬浮微粒气体中的悬浮微粒,如烟如烟,雾雾等等)microflora 微植物群微植物群respiratory 呼吸的呼吸的abrasion磨损磨损boring 打眼；钻进；钻探打眼；钻进；钻探extraction开采开采longwall长壁开采法长壁开采法shearer（滚筒式）采煤机（滚筒式）采煤机 教学目的教学目的 深入理解深入理解Ventilation、Water sprays等等内容，达到熟练阅读和正确、通顺地内容，达到熟练阅读和正确、通顺地翻译的程度；了解翻译的程度；了解Dust collectors等等内容，达到比较熟练

3、和比较通顺翻译内容，达到比较熟练和比较通顺翻译的程度。的程度。 LESSON 11 Methods of Dust Control 教学重点、难点教学重点、难点 Ventilation 课时安排课时安排 1.5 credit hour授课方法授课方法 讲授与讨论相结合讲授与讨论相结合LESSON 11 Methods of Dust Control 复习旧课复习旧课1回忆回忆SHT 、chemisorption（化学吸附（化学吸附作用）专业词汇的中文含义；氧化作用作用）专业词汇的中文含义；氧化作用（oxidation）、采空区（）、采空区（goaf or gob）、）、自燃倾向性自燃倾向性su

4、sceptibility to spontaneous combustion英文表达。英文表达。2Please describe the primary dangers of concealed fires. (the evolution of carbon monoxide, the ignition of methane and combustion progressing into airways to produce open fires)LESSON 11 Methods of Dust Control The natural atmosphere that we breathe c

5、ontains not only its gaseous constituents but also large numbers of liquid and solid particles. These are known by the generic dinerik name aerosols rsl. They arise from a combination of natural and industrial sources including condensation(,kndensein压缩；凝结；冷压缩；凝结；冷凝凝) , smokes, volcanic activity, so

6、ils and sands, and microflora. LESSON 11 Methods of Dust Control generic name 通用名通用名 类属名类属名 aerosol 浮质浮质(气体中的悬浮微粒气体中的悬浮微粒,如烟如烟,雾雾) microflora 微植物群微植物群 The natural atmosphere that we breathe contains not only its gaseous constituents but also large numbers of liquid and solid particles. These are kno

7、wn by the generic name aerosols. 我们呼吸的自然大气中，不仅包含气态成我们呼吸的自然大气中，不仅包含气态成分，而且还包含大量的液体和固体微粒。分，而且还包含大量的液体和固体微粒。它们统一名称为悬浮微粒。它们统一名称为悬浮微粒。They arise from a combination of natural and industrial sources including condensation, smokes, volcanic activity, soils and sands, and microflora. 悬浮微粒的产生有自然方面又有工业悬浮微粒的产生

8、有自然方面又有工业方面的原因，这包括：凝结、烟气、方面的原因，这包括：凝结、烟气、火山活动、沙土和微植物群。火山活动、沙土和微植物群。Most of the particles are small enough to be invisible to the naked eye. Dust is the term we use in reference to the solid particles. The physiologies of air-breathing creatures have evolved to be able to deal efficiently with most o

9、f the aerosols that occur naturally. LESSON 11 Methods of Dust Control physiology ,fizildi 生理学生理学 Most of the particles are small enough to be invisible to the naked eye. Dust is the term we use in reference to the solid particles.大部分微粒足够小，以至于肉眼大部分微粒足够小，以至于肉眼看不到。我们使用粉尘这个术语看不到。我们使用粉尘这个术语特指这种固体颗粒。特指这种

10、固体颗粒。The physiologies(,fizildi生理学生理学,生理机生理机能能)of air-breathing creatures have evolved to be able to deal efficiently with most of the aerosols that occur naturally.呼吸空气的生物的生理机能已进化为能呼吸空气的生物的生理机能已进化为能够有效地对付自然情况下产生的悬浮颗够有效地对付自然情况下产生的悬浮颗粒。粒。However, within closed industrial environments, concentrations o

11、f airborne particulates may reach levels that exceed the ability of the human respiratory system to expel them in a timelytaimli manner. In particular, mineral dusts are formed whenever rock is broken by impact, abrasion, crushing, cutting, grinding or explosives. LESSON 11 Methods of Dust Control H

12、owever, within closed industrial environments, concentrations of airborne particulates may reach levels that exceed the ability of the human respiratory system to expel them in a timely manner. 然而，在封闭的工业环境内，悬浮空然而，在封闭的工业环境内，悬浮空气中的微粒浓度可能超过人类呼吸系气中的微粒浓度可能超过人类呼吸系统能及时排除它们的程度。统能及时排除它们的程度。In particular, min

13、eral dusts are formed whenever rock is broken by impact, abrasionbrein , crushing, cutting, grinding raindi or explosives尤其是，只要岩石受撞击、磨损、破尤其是，只要岩石受撞击、磨损、破碎、切割、研磨或者爆破碎裂时，就碎、切割、研磨或者爆破碎裂时，就能形成矿尘。能形成矿尘。The fragments that are formed are usually irregular in shape. The large total surface area of dust part

14、icles may render(rend致使致使)them more active physically, chemically and biologically than the parent material. This has an important bearing on the ability of certain dusts to produce lungl diseases.LESSON 11 Methods of Dust Control have a bearing on upon 关系到关系到., 影响到影响到.render assistance. 给予给予(提供提供)援

15、助援助The fragments that are formed are usually irregular in shape. 形成的碎片通常在形状上是不规则形成的碎片通常在形状上是不规则的。的。The large total surface area of dust particles may render them more active physically, chemically and biologically than the parent material. 物质破碎后形成的尘粒总表面积增大，从物质破碎后形成的尘粒总表面积增大，从而在物理、化学和生物方面活性增强。而在物理、化学

16、和生物方面活性增强。This has an important bearing on the ability of certain dusts to produce lung diseases.这使某些粉尘能够引起肺病。这使某些粉尘能够引起肺病。The three major control methods used to reduce airborne dust in tunnels and underground mines: ventilation, water, and dust collectors.LESSON 11 Methods of Dust Control dust col

17、lector 吸尘器吸尘器dry centrifugalsentrifjul collector 干式离心除尘器干式离心除尘器The three major control methods used to reduce airborne dust in tunnels and underground mines: ventilation, water, and dust collectors.减少隧道内和地下矿山中的悬减少隧道内和地下矿山中的悬浮粉尘，有三种主要控制方法：浮粉尘，有三种主要控制方法：通风、水和集尘器。通风、水和集尘器。VentilationVentilation air red

18、uces dust through both dilution and displacement. The dilution mechanism operates when workers are surrounded by a dust cloud and additional air serves to reduce the dust concentration by diluting the cloud. LESSON 11 Methods of Dust Control Ventilation air reduces dust through both dilution and dis

19、placement. 通风气流通过稀释和置换减少通风气流通过稀释和置换减少粉尘粉尘The dilution mechanism operates when workers are surrounded by a dust cloud and additional air serves to reduce the dust concentration by dilutinge：dailju:t the cloud.当工人处于粉尘云的包围中，稀释过程当工人处于粉尘云的包围中，稀释过程起作用，附加的气流通过稀释尘云，减起作用，附加的气流通过稀释尘云，减少粉尘的浓度。少粉尘的浓度。The displa

20、cement mechanism operates when workers are upwind of dust sources and the air velocity is high enough to reliably keep the dust downwind.LESSON 11 Methods of Dust Control The displacement mechanism operates when workers are upwind of dust sources and the air velocity is high enough to reliably keep

21、the dust downwind.当工人位于尘源的上风方向，而且当工人位于尘源的上风方向，而且气流速度足够高，使之能够可靠地气流速度足够高，使之能够可靠地保持粉尘处在下风方向时，置换过保持粉尘处在下风方向时，置换过程起作用。程起作用。 Dilution Ventilation. The basic principle behind dilution ventilation is to provide more air and dilute the dust. Most of the time the dust is reduced roughly in proportion to the i

22、ncrease in airflow, but not always. The cost of and technical barriers to increased airflow can be substantial, particularly where air already moves through ventilation ductwork or shafts at velocities of 3,000 ft/min or more. Substantial (相当相当)大的大的 ductwork n. 管道系统管道系统 LESSON 11 Methods of Dust Con

23、trol 1) Dilution Ventilation. The basic principle behind dilution ventilation is to provide more air and dilute the dust. 1）稀释通风）稀释通风 稀释通风的基本原稀释通风的基本原理是提供更多的空气来稀释粉尘。理是提供更多的空气来稀释粉尘。Most of the time the dust is reduced roughly in proportion to the increase in airflow, but not always. 大多数情况下，减少的粉尘与增大多数

24、情况下，减少的粉尘与增加的风量大致成比例，但并不总加的风量大致成比例，但并不总是这样。是这样。The cost of and technical barriers to increased airflow can be substantial, particularly where air already moves through ventilation ductwork or shafts at velocities of 3,000 ft/min or more.增加风量的费用和技术障碍可能是关键，尤其增加风量的费用和技术障碍可能是关键，尤其是在流过通风管道或井筒的气流速度已达到是在流过

25、通风管道或井筒的气流速度已达到3000英尺英尺/分（分（914.4m/min）以上的矿井，更）以上的矿井，更是如此。是如此。2) Displacement Ventilation. The basic principle behind displacement ventilation is to use the airflow in a way that confinesknfain the dust source and keeps it away from workers by putting dust downwind of the workers. LESSON 11 Methods

26、of Dust Control 2) Displacement Ventilation. 2）置换通风）置换通风The basic principle behind displacement ventilation is to use the airflow in a way that confines the dust source and keeps it away from workers by putting dust downwind of the workers. 置换通风的基本原理是利用风流置换通风的基本原理是利用风流约束尘源，使粉尘处在下风位置，约束尘源，使粉尘处在下风位置，从

27、而远离工人。从而远离工人。Every tunnel or mine passage with an airflow direction that puts dust downwind of workers uses displacement ventilation. In mines, continuous miner faces or tunnel boring machines on exhaust ventilation use displacement ventilation. LESSON 11 Methods of Dust Control continuous miner fac

28、es: 连续采煤机工作面连续采煤机工作面tunnel boring machines: 隧道掘进机隧道掘进机Every tunnel or mine passage with an airflow direction that puts dust downwind of workers uses displacement ventilation.任一隧道或矿山通道中，如风流方任一隧道或矿山通道中，如风流方向使粉尘处在下风方向，使用的就向使粉尘处在下风方向，使用的就是置换通风。是置换通风。In mines, continuous miner faces or tunnel boring mach

29、ines on exhaust ventilation use displacement ventilation. 在矿山中，连续采煤机工作面或隧在矿山中，连续采煤机工作面或隧道掘进机的回风系统，使用的是置道掘进机的回风系统，使用的是置换通风换通风Enclosure of a dust source, such as a conveyor belt transfer point, along with extraction of dusty air from the enclosure, is another example of displacement ventilation. Displ

30、acement ventilation can be hard to implement. LESSON 11 Methods of Dust Control implement vt 贯彻贯彻 执行执行Enclosure of a dust source, such as a conveyor belt transfer point, along with extraction of dusty air from the enclosure, is another example of displacement ventilation. 在尘源附近，例如运输皮带转在尘源附近，例如运输皮带转载

31、点，将尘源连同周围多尘空载点，将尘源连同周围多尘空气一起抽出去，是置换通风的气一起抽出去，是置换通风的另一个例子。另一个例子。Displacement ventilation can be hard to implement. 置换通风很难实现置换通风很难实现However, if done well, it is the most effective dust control technique available, and it is worth considerable effort to get it right. The difficulty is that when workers

32、 are near a dust source, say, 10 to 20 ft from the source, keeping them upwind requires a substantial air velocity, typically between 60 and 150 ft/min. There is not always enough air available to achieve these velocities.LESSON 11 Methods of Dust Control However, if done well, it is the most effect

33、ive dust control technique available, and it is worth considerable effort to get it right. 然而，如果做得好，置换通风是能利用的然而，如果做得好，置换通风是能利用的最有效的粉尘控制技术，值得付出大量的最有效的粉尘控制技术，值得付出大量的努力，使其运行良好。努力，使其运行良好。The difficulty is that when workers are near a dust source, say, 10 to 20 ft from the source, keeping them upwind req

34、uires a substantial air velocity, typically between 60 and 150 ft/min. 困难之处在于：当工人处在尘源附近困难之处在于：当工人处在尘源附近时，比方说时，比方说1020英尺，使他们位于英尺，使他们位于上风处需要相当大的风速（一般要上风处需要相当大的风速（一般要60150英尺英尺/分）。分）。There is not always enough air available to achieve these velocities.并不总有足够的风量能达到这么大的风并不总有足够的风量能达到这么大的风速。速。Water spraysTh

35、e role of water sprays in mining is a dualdju:l one: (1) wetting of the broken material being transported and (2) airborne capture. Of the two, wetting of the broken material is far more effective.LESSON 11 Methods of Dust Control The role of water sprays in mining is a dual one: (1) wetting of the

36、broken material being transported and (2) airborne capture. Of the two, wetting of the broken material is far more effective.开采中喷水的作用是双重的：（开采中喷水的作用是双重的：（1）湿）湿润正被运输的粉碎的物质；（润正被运输的粉碎的物质；（2）空中）空中捕获。这两个作用中，湿润粉碎物质捕获。这两个作用中，湿润粉碎物质更加有效。更加有效。Adequate wetting is extremely important for dust control. The vast

37、majority of dust particles created during breakage are not released into the air, but stay attached to the surface of the broken material. Wetting this broken material ensures that the dust particles stay attached. LESSON 11 Methods of Dust Control Adequate wetting is extremely important for dust co

38、ntrol. The vast majority of dust particles created during breakage are not released into the air, but stay attached to the surface of the broken material. 适度的湿润对于粉尘控制非常重要。在粉适度的湿润对于粉尘控制非常重要。在粉碎过程中产生的粉尘颗粒大部分没有释放碎过程中产生的粉尘颗粒大部分没有释放到空气中，而是附着在粉碎物的表面。到空气中，而是附着在粉碎物的表面。Wetting this broken material ensures th

39、at the dust particles stay attached. 湿润破碎物能够确保粉尘颗粒保持附着湿润破碎物能够确保粉尘颗粒保持附着状态。状态。As a result, adding more water can usually (but not always) be counted on to reduce dust. For example, coal mine operators have been able to reduce the dust from higher longwall production levels by raising the shearer wate

40、r flow rate to an average of 100gpm. LESSON 11 Methods of Dust Control As a result, adding more water can usually (but not always) be counted on to reduce dust. 因此，通常加水越多越能降因此，通常加水越多越能降低粉尘（但并不总是如此）。低粉尘（但并不总是如此）。For example, coal mine operators have been able to reduce the dust from higher longwall p

41、roduction levels by raising the shearer water flow rate to an average of 100gpm例如，煤矿经营员已能够通过提高例如，煤矿经营员已能够通过提高（滚筒式）采煤机的水流速度平均达（滚筒式）采煤机的水流速度平均达到到100 gpm (每分钟每分钟100加仑加仑)，来减，来减少生产水平较高的长壁开采工作面的少生产水平较高的长壁开采工作面的粉尘。粉尘。Compared to the amount of coal mined, on a weight basis, this 100gpm is equivalent to 1.9%

42、 added moisture from the shearer alone. Unfortunately, excessive moisture levels can also result in a host of materials handling problems, operational headaches, and product quality issues, so an upper limit on water use is sometimes reached rather quickly. LESSON 11 Methods of Dust Control Compared

43、 to the amount of coal mined, on a weight basis, this 100gpm is equivalent to 1.9% added moisture from the shearer alone. 与开采煤的数量相比，以重量为基础，由与开采煤的数量相比，以重量为基础，由采煤机每分钟单独加入的采煤机每分钟单独加入的100加仑水分等于加仑水分等于开采煤量的开采煤量的1.9%。Unfortunately, excessive moisture levels can also result in a host of materials handling p

44、roblems, operational headaches, and product quality issues, so an upper limit on water use is sometimes reached rather quickly. 可惜的是，过高的水分也能导致许多材料可惜的是，过高的水分也能导致许多材料的处理问题、操作上的不便和产品质量问的处理问题、操作上的不便和产品质量问题，所以，用水的上限有时能很快达到。题，所以，用水的上限有时能很快达到。As a result, an alternative to simply adding more water is to en

45、sure that the broken material is being wetted uniformly.LESSON 11 Methods of Dust Control As a result, an alternative to simply adding more water is to ensure that the broken material is being wetted uniformly.因而，确保粉碎的物质能够得到均因而，确保粉碎的物质能够得到均匀加湿是替代仅靠增加水量降尘的匀加湿是替代仅靠增加水量降尘的另一种方法。另一种方法。Under actual minin

46、g conditions, the typical water spray operating at 100 psi and 1-2 gpm gives no more than 30% airborne capture of respirable dust. This is not as good as lab tests would lead one to believe. In lab tests, sprays were usually confined in a duct, and all of the dust was forced to pass through the spra

47、y. LESSON 11 Methods of Dust Control psi:Pounds per Square Inch. 磅磅/平方英尺平方英尺gpm: Gallons Per Minute Under actual mining conditions, the typical water spray operating at 100 psi（pounds per square inch）and 1-2 gpm gives no more than 30% airborne capture of respirable dust.This is not as good as lab te

48、sts would lead one to believe. In lab tests, sprays were usually confined in a duct, and all of the dust was forced to pass through the spray. 这并不与实验室试验的结果完全一样。这并不与实验室试验的结果完全一样。在实际开采条件下，以在实际开采条件下，以100psi和和1-2gpm实施典型的水喷雾，最多能捕获实施典型的水喷雾，最多能捕获30%的风载可吸入粉尘。的风载可吸入粉尘。在实验室的试验中，水喷雾通常限定在管在实验室的试验中，水喷雾通常限定在管道中，所

49、有的道中，所有的 粉尘被迫穿过水喷雾。粉尘被迫穿过水喷雾。However, under actual mining conditions, dust clouds are unconfined. In all sprays, the moving droplets exert iz:t dragdr on the adjacent (deisnt邻邻近的近的) air; thus, sprays act to move the air. Because of this air entrainment effect, if a spray is aimed at an unconfined du

50、st cloud, it will carry in air that spreads the cloud, thus making capture by the spray less efficient. LESSON 11 Methods of Dust Control Entrainment n. 带走带走,夹带夹带 However, under actual mining conditions, dust clouds are unconfined. In all sprays, the moving droplets exert drag on the adjacent air; t

51、hus, sprays act to move the air. Because of this air entrainment effect, if a spray is aimed at an unconfined dust cloud, it will carry(被携带被携带) in air that spreads the cloud, thus making capture by the spray less efficient. Attempts to improve the airborne capture efficiency of sprays have not met w

52、ith practical success. One approach has been to reduce droplet size, based on the notion that capture by smaller droplets is more efficient.LESSON 11 Methods of Dust Control Notionnun n.概念概念, 观念观念, 想法想法, 意见意见, 打算打算, Attempts to improve the airborne capture efficiency of sprays have not met with prac

53、tical success.One approach has been to reduce droplet size, based on the notion that capture by smaller droplets is more efficient.Dust collectorsDust collectors can play a valuable role in dust reductionif space is available to locate the collector and if the collector efficiency is high. Dust coll

54、ectors range from low-volume filtration filtrein systems used in the cabs kb of mining equipment to high-volume wet collectors used on continuous miners in coal mines.LESSON 11 Methods of Dust Control Dust collectors can play a valuable role in dust reductionif space is available to locate the colle

55、ctor and if the collector efficiency is high. Dust collectors range from low-volume filtration systems used in the cabs of mining equipment to high-volume wet collectors used on continuous miners in coal mines.It is important to recognize that the efficiency of a dust collector is the filtration eff

56、iciency of the unit times the capture efficiency of its inlet inlet . For collectors properly designed to trap respirable dust, the filtration efficiency is usually quite high, in the 90%-95% range. LESSON 11 Methods of Dust Control It is important to recognize that the efficiency of a dust collector is the filtration efficiency of