安全工程专业英语.docx
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安全工程专业英语.docx
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安全工程专业英语
安全工程专业英语
安全工程专业
(矿山通风、安全和健康方向)
Contents
PartⅠMineVentilation
PartⅡMineSafety
PartⅠMineVentilation
LESSON1
IntroductiontoMineVentilation
Introduction
Mineventilationinvolvesthecontroloftheatmosphericenvironment.Thisrequirescontroloftheairqualityandairmovementtosatisfytherequirementsforthehealth,safetyandcomfortofmineworkers.Minimumstandardsaresetoutinthevariousstatesminesregulation.Somearedescriptive,specifyingthestandardsrequired(eg.Victoria),andsomeareprescriptive,detailingexactlyhowthestandardsaretobeachieved(eg.W.A.).
PurposesofMineVentilation
Properlyengineeredcontrolofthemineatmosphereisrequiredto:
·providefreshair(oxygen)formentobreathe
·provideasourceofoxygenforinternalcombustionenginesinmachinery
·diluteatmosphericcontaminantstoacceptablelevels
·maintaintemperatureandhumiditywithinacceptablelimits
·removeatmosphericcontaminantsfromthemine.
HistoricalDevelopment
Mineventilationistwofoldinpurpose:
first,itmaintainslife,andsecondlyitcarriesoffdangerousgases.Thehistoricroleofventilationwastoprovideaflowoffreshairsufficienttoreplacetheoxygenconsumedbytheminersworkingunderground.
Today'smineventilationprimarilydealswithnoxiousgases(mainlygeneratedbytracklessequipmentunderground).
Inthepast,miningoccurrednear thesurfacewherenaturallightandventilation wasavailable.Fireswereusedtodrawfreshairintothemineandexhaustshaftsventedthehotsmokeoutofthemine.
LongbeforecoalwasminedinNorthAmerica,collieriesinEuropeweresunkwithdualentrances;onethroughwhichairflowedintothemineandanotherthroughwhichairflowedout.Initially,mineventilationwasassistedbyundergroundfurnaces,whichusedthepracticalprinciplethattheupdraftofafirecausedasuctionwhichdrewairoutofthemineandthisairwasreplacedbyairwhichwaspulledintofilltheopening.
Canariesaresaidtohavebeenusedtodetectgasincoalminesintheearlystagesofcoalmining.Thissensitivebirdwouldbetakenintotheworkingsand,ifitperished,thecollierswouldimmediatelyleavethemine.
However,beforethe1870s,managersandqualifiedpersonswereusingsafetylampstodetectgas.Thesesafetylampssoonreplacedoillampsandopenflaredcandlesasasourceofworkinglight.
Soon,smallhand-turnedfanswereusedtoblowoutgasfromworkingplacesintomainaircurrents.Trapdoorswerestrategicallyplacedaspartoftheventilationsystemtoguidetheflowofairtoorfromselectedareas."Trapper"boyswerepostedatthebusierdoorstoopenthemforthepassageofcoal,materialsandmen."Aircourses"werefrequentlycutthroughcoalandrock.
Inthe1920sthehand-turnedfanswerereplacedwithair-poweredsmallturbinefans.Largefansofthesuctiontypewereplacedonthesurfaceandgraduallyincreasedinsize.Airfromsurfacecompressorswaspipedintotheminetopowermachineryandtoassistinventilation.
PropertiesofAir
Theconstituentsofairare:
Constituent
Volume
Mass%
Nitrogen(N2)
78.09
75.53
Oxygen(O2)
20.95
23.14
CarbonDioxide(CO2)
0.03
0.04
RareGases(Ar,H2,He,etc.)
0.93
1.28
AtmosphericPressureatanypointisduetotheweightofairaboveit,andvarieswithaltitude(whichdeterminestheheightoftheaircolumn),andairdensity(whichisdeterminedbytemperatureandmoisturecontent).Standardatmosphericpressureistakenas760mmofHg,(101.3kPa)atmeansealevel,anditvariesbyaboutlkPaforevery90mincreaseordecreaseinaltitude.
AtmospherictemperatureisnormallygivenaccordingtotheCelsiusscale(°C),buttheKelvinscale(°K)maybeused.
0°K
=
-273°C
(absolutezero)
273°K
=
0°C
(freezingpointofwater)
373°K
=
100°C
(boilingpointofwater)
Airisacolorless,odorless,tastelessgasmixturewhichsupportscombustionandlife.Inmineventilationweareusuallydealingwithanair/watervapormixturewhichhasdifferentthermodynamicpropertiestodryair.Thedensityofdryairis1.21kg/m³atstandardatmosphericpressure(101.3kPa)andtemperature(15°C).
NewWordsandExpressions
Mineventilation矿山通风
internalcombustionengine内燃机
dilute冲淡,变淡,变弱,稀释
contaminant污染物
noxious有害的
exhaustshaft出风井
colliery煤矿
sink挖掘
suction吸入,吸力,抽气,抽气机,抽水泵,吸引
canary[动]金丝雀,淡黄色
trapdoor通风门
trapper设阱捕兽者,[矿]矿井风门开关管理
moisturecontent湿度
thermodynamicadj.热力学的,使用热动力的
LESSON2
EnergyChangesinFluidFlow
MineVentilationisnormallyanexampleofasteadyflowprocess,thatis,oneinwhichnoneofthevariablesofflowchangeswithtime.Transitionandlossinenergyareinvolvedinsuchaprocess,anditisimportanttounderstandtheirnatureandtobeabletoexpressthemmathematically.Energychangesarebasictothecalculationoftheminequantityandhead,oneoftheultimateobjectivesofmine-ventilationengineering.Anexpressionrelatingtheenergyvariablesmaybedevelopedasfollows.
Thetotalenergyatanysectioninamovingasfluidconsistsofthesumoftheinternalstatic,velocity,potential,andheatenergiesatthatsection.Assumearealfluidmovinginaconduit,andconsidertheenergychangesthatoccurbetweenanytwosectionsinthesystem.Theheatchangesisgenerallynegligiblecomparedtotheotherterms,exceptindeepminesoronesnaturallyventilated,andtheadditionofmechanicalenergyisusuallyconsideredseparately.Omittingthesetermsfornow,thetotalenergyatsection1equalsthetotalenergyatsection2,plustheflowenergylossesoccurringbetween1and2,or
(totalenergy)1=(totalenergy)2+(flowenergylosses)1-2
(1)
substitutingexpressionsforthevariousenergytermsanddisregardingtheminorchangeininternalenergy,thefollowinggeneralenergyequationforfluidflowresults:
(2)
Where:
--------staticenergy;
-------velocityenergy;
Z,,Z2----------potentialenergy;
H1-2----------flowenergyloss.
Equation2isrecognizedasthefamiliarBernoulliequation,applicabletoallfluid-flowprocesses.Inthisform,itappliedonlytoanincompressiblefluid,whichairisassumedtobeinnearlyallmineventilationbecauseofminorchangesinairdensity.
Eachtermintheequationisactuallyaspecificenergy,inunitofm.kg/kg,orm.Sincemisameasureoffluidhead,thesetermscanalsobereferredtoaspressureheadsorsimplyheads.Indealingwithair,itiscustomarytoemploymmofwaterrathermofanairastheunitofhead.
Acceptingtheequivalencyofspecificenergyandhead,thegeneralequationaswritteninEq.1canalsobeexpressed:
(3)
Where:
Httotalhead;andEq.2canbeexpressed:
Hs1+Hv1+Hz1=Hs2+Hv2+Hz2+H1-2(4)
WhereHsisstatichead,Hvisvelocityhead,andHziselevationorpotentialhead,allheadshavetheunitofmmwater.
TheseversionsoftheBernoullienergyequation(Eq.2and4)arebothbasicandgeneralandthemostusefultoemployinmineventilation.Inrelatingthestaticvelocity,potential,andtotalheadsplusthelossesflow,theenergyequationpermitswritingofanexpressionencompassingallflowvariablesbetweenanytwopointsintheventilationsystem.Thesepointsmaybeselectedatthebeginningandendofthesystem(theentranceanddischargeofminefortheaircircuit),enablingthecalculationofthecharacteristicsfortheentiresystem(themineheads).
NewWordsandExpressions
head液压,气压:
液体或气体产生的压力;压差
staticenergy静压能
velocityenergy动能
potentialenergy位能
incompressiblefluid不可压缩流体
LESSON3
FaceVentilation
Unlesstheairisproperlydistributedtotheface,themineventilationsystemisnotperformingitsprimaryfunction[1].Whileithasalwaysbeenrecognizedthatthislastpartofventilationisthemostimport,itisalsothemostdifficulttoachieve.
Therearebasicallytwomethodsofventilatingtheblindentriesaheadofthelastopencrosscut:
theuseoflinebratticesortheinstallationofauxiliaryfans.Eachtechniquehasitsdefendersaswellasitsoutspokencritics[2].
LineBrattices
Thelinebratticeisessentiallyaspacedividerortemporarypartitionmadeofanimperviousmaterialthatisinstalledandmaintainedverycarefullyandkeptasclosetothefaceaspossible[3].Itspurposeistoguidetheairflowthroughthefaceareaandlastopencrosscutandintothereturn.Bratticeswereformerly(andtosomeextentstillare)madeofuntreatedjute,butnylonreinforcedplasticsandsimilarmaterialsaremorecommonlyusedinthemtoday.Whilethemoreeffectivematerialisinvariablyhigherininitialcost,itresultsinloweroverallexpenseinthatitallowsforgreaterreuseandlessairleakage.
Thelinebratticeisinstalledsoastosplittheheadinglongitudinallyandthusprovidesaninletaswellasareturnfromthefacetothelastopencrosscut.Sincetheminingmachinemusthaveroomtomaneuverononesideofthebrattice,itisnotpracticaltosplittheentryevenly,soawidesideisprovidedforthemachine.Theairmaybebroughtupthenarrowsideand,afteritsweepsbytheface,returnedonthewideside,asintheblowingsystemoritmaybeforcedinthereversedirectionasshownintheexhaustsystem[4].Sincetheblowingsystemproducesahighvelocityofairattheface,itachievessuperiorgasdilution,buttheair,nowcontaminatedwithgasanddust,returnsoverthemachineanditsoperator.Asaresult,thissystemisrarelyusedtoday.Themorecommonlyemployedexhaustsystem,withintakeaircominginonthewidesideofthebratticeandreturningonthenarrowside,eliminatesthisproblembecausethefreshairpassesoverthemachi
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