《专业英语》课件Unit-37

Unit 37VentilationTextAccordingtotheventilationsystemofthepower： Accordingtotheventilationsystemofpower,ventilationmodecanbedividedintonaturalventilationandmechanicalventilation.

1.Naturalventilation Naturalventilationistorelyonindoorandoutdoorairtemperaturedifferencecausedbythehotpressingandoutdoorwindpressurecausedbythewaytorealizetheairventilation. 1）Undertheactionofthermalnaturalventilation Adiagraminfigure1forusingthermalnaturalventilation,duetothehighairtemperatureintherooms,densityissmall,soproducedakindofupwardforce,tomaketheroomairrisesanddischargefromtheupperwindow,outdoorcoldairintotheindoorfromtheroombelowtheWindowsoftheholesorcracks.Undertheactionofthisventilationmodeiscalledthermalnaturalventilation.Figure1NaturalventilationunderthehotactionText 2）thenaturalventilationundertheactionofwindpressure Figure2isanaturalventilationdiagrambytheactionofwindpressure,Airflowentertheroomfromthewindowsanddoorswhichonthebuilding’swindward.AtthesametimeSqueezeouttheindoorairfromthewindowsanddoorswhichonthebuilding’sleeside.Therefore,akindofnaturalventilationisformedintheroomcausedbywind.Thiswayofventilationiscalledthenaturalventilationundertheactionofairpressure. NaturalventilationcanbedividedintoOrganizednaturalventilationandunorganizednaturalventilation.TheOrganizednaturalventilationisconductedbytheworkshopsSidewindowandskylights,Bycontrollingitsopeningdegree,Adjusttheairinflowanddisplacement;Theunorganizednaturalventilationisconductedbythedoorsandwindowsaperture.Figure2NaturalventilationunderwindpressureText Therearemanyfactorswhichcanaffectthenaturalventilation,Suchasindoorandoutdoorairtemperature,outdoorairflowvelocityandflowdirection,shopWindowsanddoorsholessizeandlocation.SotheAirvolumeisconstantlychanging.Soweneedtoconstantlyadjusttheairoutletopeningdegreeaccordingtothespecificsituationtometthedemand. Naturalventilationischaracterizedbysmallinvestment,goodeconomy,buttheeffectandapplicablescopeissmall,ItismainlyusedforIndustrialworkshop;Becauseoftheuncertaintyofthenaturalwind,So,Undernormalcircumstances,weregardthenaturalventilationbywindeffectswhendoingthedesign.

2.Mechanicalventilation

Mechanicalventilationistheuseofpowergeneratedbytheventilators,ventilatingmode.Figure3istheuseoftheexhaustpipeexhaustuniformly.Figure4iswilldrainawayharmfulgasesfromseverallocallocations. Figure3uniformexhaustsystemFigure4 localexhaustsystemTextFigure5isthedustremovalsystem,thedustremovalsystemcanalsobeusedtorecyclepowder.Figure6systemformechanicalventilation,outdoorairundertheactionoffanbyblindsintotheintakechambers.Afterhitchesininletchambersfilter,heaterheating,throughtheductintotheventilationroom.Figure5 thedustremovalsystem1—Pestscollector；2—airduct；3—fan；4—dustcollectorFigure6 mechanicalventilationsystem1—theshutters；2—airfilter；3—airheater；4—theventilator；5—duct；6—airtreatmentroom；7—motor；8—airdistributorText

Accordingtotheroleoftheventilationsystem: Accordingtothescopeoftheventilationsystem,ventilationsystemcanbedividedintocomprehensiveventilationandlocalventilation. 1.Thecomprehensiveventilation Comprehensiveventilationisintheroomthoroughlyventilatedtakeabreath.Thecomprehensiveventilation′spurposeistodilutethepollutantsintheairandprovidetheheatoftheroomneeds.Characterizedbyawiderange,largeairvolume,highinvestmentandoperatingcost,whenusinglocalventilationmodeisdifficulttoensurehygienestandardsadopted. Comprehensiveventilationcanmakeuseofmechanicalventilation,alsocanbeusetonaturalventilationtoachieve,thecomprehensiveventilationcanbedividedintocomprehensiveexhaustandoverallsupply.

2.Localventilation Localventilationcanbedividedintolocalexhaustandlocalsupply.TextLocalexhaustisafterdischargetocapture,purifythepestsontheoutside,Andlocalairsupplyareprocessed,conformtotherequirementsoftheairtothelocalworkingplace,toensuretheairconditionoflocalarea. Thecharacteristicsoflocalventilationisthepestcontroleffectisgood,smallvolume,smallinvestment,lowoperatingcost.Accordingtothecharacteristicsoftheventilationsystem: Accordingtothecharacteristicsoftheventilationsystem,ventilationsystemcanbedividedintoairsupplyandexhaustair. 1.Thesupplyair Thefreshairintotheindooriscalledsupplyair. 2.Exhaustair Thefoulairinsidetheroomafterprocessingtomeetdischargestandardsemissionscalledexhaust.Inactualengineering,fromtheperspectiveoftechnicaleconomy,thepriorityshouldbegiventothenaturalventilation,whenitcannotsatisfytheneedtoadoptmechanicalventilation;Giveprioritytowithlocalventilation,adoptsthecomprehensiveventilationwhenitcannotsatisfytheneed. Inpracticalengineering,usingawayofventilationisoftencannotsatisfytheneedoftheeffect,isusuallyavarietyofventilationmethodisusedincombination.Louver n.百叶窗Piece n.(通风)部件control

valve 调节阀

control

velocity 控制风速

controlled

natural

ventilation 有组织自然通风

controlled

plant 调节对象cross-ventilation 穿堂风exhaust

air

rate 排风量

exhaust

fan 排风机

local

air

suppiy

system 局部送风系统

local

exhaustventilation

(LEV) 局部排风NewWordsandPhrasesNotes（1）Naturalventilationistorelyonindoorandoutdoorairtemperaturedifferencecausedbythehotpressingandoutdoorwindpressurecausedbythewaytorealizetheairventilation. 自然通风是依靠室内和室外空气温差引起的热压及室外风压造成的方式实现空气通风。（2）Therearemanyfactorswhichcanaffectthenaturalventilation,Suchasindoorandoutdoorairtemperature,outdoorairflowvelocityandflowdirection,shopWindowsanddoorsholessizeandlocation. 有许多影响自然通风的因素，例如，室内和室外空气温度、室外空气流速和流向、门和窗孔的大小及位置等。（3）Accordingtothescopeoftheventilationsystem,ventilationsystemcanbedividedintocomprehensiveventilationandlocalventilation. 根据通风系统的作用范围，通风系统可以分为全面通风和局部通风。（4）Thecharacteristicsoflocalventilationisthepestcontroleff