SectionTwo

Unit4：ToolsandEquipmentUnit5：ThermometersUnit6：ElectricalInstrumentUnit5：ThermometersNewWords&ExpressionsTextNotestothe

TextExerciseNewWords&Expressions指針；指示器；教鞭；暗示remote

adj.n.

遙遠的；偏僻的；疏遠的遠程tensionn.vt.

張力，拉力；使緊張；使拉緊bimetallicadj.[材]雙金屬的；復本位制的mercury

n.[化]汞，水銀alcohol

n.酒精，乙醇versatileadj.通用的，萬能的；多面手的ambient

adj.周圍的；外界的；環(huán)繞的n.周圍環(huán)境im-mediatelyadv.conj.

立即，立刻；直接地一…就increment

n.[數(shù)]增量；增加；增額；盈余pointer

n.NewWords&Expressions校正；調(diào)整；測定口徑skin

皮，皮膚，(任何物體的)外殼dome(懷表的)黑蓋；(表的)內(nèi)蓋dissimilar

adj.不同的，不一樣的，異樣的ambient

adj.周圍的；外界的；環(huán)繞的n.周圍環(huán)境fumesn.【化學】煙氣rugged

adj.堅固的；高低不平的；粗糙的thermistorn.[電子]熱敏電阻；電熱調(diào)節(jié)器calibrate

vt.Text

溫度計用來測量熱度。應該按照它的用途來選擇溫度計。首先要考慮的是安裝---直接安裝還是遙控讀數(shù)。如果必須是遙控讀數(shù)，氣動式溫度計最好。它具有一個閉合的充滿介質(zhì)的彈簧管。溫度傳感器一端是指示燈。測量溫度時，常用以下四種溫度計：袖珍溫度計雙金屬溫度計熱電偶溫度計電阻溫度計

袖珍溫度計Thermometersareusedtomeasureheat.Athermome-tershouldbechosenaccordingtoitsapplication.Con-siderfirstthekindofinstallation--directmountingorremotereading.Ifremotereadingsarenecessary,thenthevaportensionthermometerisbest.Ithasaclosed,filledBourdontube.

1Abulbisatoneendfortemperaturesensing.Fourcom-montypesofthermometersareusedtomeasuretemperature:PocketthermometerBimetallicthermometerThermocouplethermometerResistancethermometerText

袖珍溫度計取決于液體的膨脹。液體可以是水銀或彩色酒精。這種溫度計是通用的。可以用來測量液體，大氣，氣體及固體的溫度。實際使用中，濕的和干燥狀態(tài)都能操作。這種類型的溫度計可以適用于極強的腐蝕溶液。PocketThermometerThepocketthermometerdependsupontheex-pansionofaliquid.Theliquidmaybemercuryorcol-oredalcohol.Thistypeofthermometerisversatile.Itcanbeusedtomeasuretemperaturesofliquids,air,gas,andsolids.Forpracticalpur-poses,itcanoperatewetordry.Thistypeofther-mometercanwithstandextremelycorrosivesolutions.SeeFig.5-1AandB.Text

使用玻璃溫度計最大誤差在于常常不能在適當?shù)奈恢米x數(shù)。讀數(shù)時需要將溫度計從空調(diào)出風口移開。然后移動到處于室內(nèi)環(huán)境溫度的視線范圍。此時已經(jīng)是在若干秒或一分鐘之后讀數(shù)了。此時溫度讀數(shù)已經(jīng)不同于測量值。消除讀數(shù)誤差的簡單原則就是：當溫度計與被測介質(zhì)接觸時讀數(shù)。如果必須接觸溫度計，盡量減少手接觸的范圍。立刻讀數(shù)。Thegreatesterrorintheuseoftheglassther-mometeristhatitisoftennotreadinplace.2Itisre-movedfromtheoutletgrilleofapackagedairconditioner.Thenitiscarriedtoeyelevelintheroomatambienttemperatures.Hereitisreadafewsecondstoaminutelater.Itisreadinatemperaturedifferentfromthatinwhichitwasmeasured.Asimplerulehelpseliminateincorrectreadings:Readglassthermometerswhiletheyareactuallyincontactwiththemediumbeingmeasured.3Ifathermometermustbehandled,dosowithaslittlehandcontactaspossible.Readthethermometerim-mediately!Text

雙金屬溫度計指針式溫度計由雙金屬線圈、水銀柱、蒸氣壓來驅(qū)動。指針式溫度計有各種不同的形式，以滿足若干場合的使用。如圖5-2所示。儀表的傳感部分可以安置在其它地方。而可以在方便的地方看表盤讀數(shù)。BimetallicThermometersDialthermometersareactuatedbybimetalliccoils,mercury,orvaporpressure.Theyareavailableinvariedformsthatallowthedialtobeusedinanumberoflocations.SeeFig.5-2.Thesensingportionoftheinstrumentmaybelocatedsomewhereelse.Thedialcanbereadinaconvenientlocation.Text

BimetallicThermometersBimetallicthermometershavealineardialface.Thereareequalincrementsthroughoutanygivendialranges.Dialrangesarealsotomeethighertemperaturemeasuringneeds.Rangesupto1000°F(537.8°C)areavailable.Bimetallicthermometersareeconomical.Thereisnoneedforamachinedmovementorgearing.Thetemperature-sensitivebimetallicelementisconnecteddirectlytothepointer.Thistypeofthermometryiswelladaptedtomeasuringthetemperatureofasurface.Dome-mountedthermalprotectorsactuallyreacttothesurfacetemperatureofthecompressorskin.4Thesethermometersareusedwheredirectreadingsneedtobetaken,suchason:Pipelines;Tanks;Ovens;Ducts;Sterilizers;Heatexchangers;Laboratorytemperaturebaths.

雙金屬溫度計雙金屬溫度計具有線性刻度盤。任何給定的刻度范圍具有相當?shù)脑隽??？潭确秶部梢杂脕頋M足高溫測量需求，可達到1000°F(537.8oC)。雙金屬溫度計是經(jīng)濟型的，他不需要機械運動或齒輪。雙金屬傳感元件直接與指針相連接。這種溫度測定方法非常適用于測量表面溫度。裝有內(nèi)蓋的熱保護器可以直接對壓縮機殼體的表面溫度做出反應。這種溫度計用于需要直接讀數(shù)的場合，例如：管線；容器；烤箱；通風管；換熱器；實驗室恒溫池。

Text

ThermocoupleThermometersThermocouplesarcmadeoftwodissimilarmetals.Oncethemetalsareheated,theygiveoffanEMF(electromotiveforceorvoltage).Inuse,thethermocouplesareplacedinthemediumthatistobemeasured.Extensionwiresrunfromthethermocoupletothemeter.Themeterthengivesthetemperaturereadingattheremotelocation.Thermocouplesareeasilytapedontothesurfaceofpipestochecktheinsidetemperature.5Itisagoodideatoinsulatethethermocouplefromambientandradiatedheat.Althoughthistypeofthermometerisrugged,itshouldbehandledwithcare.Thermocouplesshouldbeprotectedformcorro-sivechemicalsandfumes..

熱電偶溫度計熱電偶溫度計有兩種不同的金屬構成。當金屬被加熱的時候，會形成不同的電勢（電動勢或電壓）。使用的時候，熱電偶溫度計放入要測量的介質(zhì)。補償導線聯(lián)接熱電偶到儀表。儀表在外部場所給出溫度讀數(shù)。熱電偶很容易固定到管子內(nèi)壁去測量內(nèi)部溫度。這是將熱電偶與外部環(huán)境及熱輻射隔絕的好主意。雖然這種溫度計是粗糙的，但仍然需要小心輕放。熱電偶溫度計必須防止化學腐蝕和煙氣。Text

ResistanceThermometersOneofthenewerwaystochecktemperatureiswithathermometerthatusesaresistance-sendingelement.Anelectricalsensingunitmaybemadeofathermistor.Athermistorisapieceofmaterialthatchangesresistancerapidlywhensubjectedtotemperaturechanges.6Whenheated,thethermistorlowersitsresistance.Thisde-creaseinresistancemakesacircuitincreaseitscurrent.Ametercanbeinsertedinthecircuit.Thechangeincur-rentcanbecalibratedagainstastandardthermometer.ThescalecanbemarkedtoreadtemperatureindegreesCelsiusordegreesFahrenheit.電阻溫度計一種新的測量溫度的方式是用電阻敏感元件。電傳感器由熱敏電阻制成，熱敏電阻是一種在溫度變化時電阻迅速變化的材料。當加熱時，電阻下降。這種電阻下降導致回路中電流增加。儀表可以接在回路中。這種電流的變化可以標定標準的溫度計?？潭瓤梢詷俗R為攝氏或華氏溫度。NotestotheTextUnit1NotestotheText1、Ithasaclosed,filledBourdontube.句中，過去分詞closed和filled并列作為Bourdontube的定語。Bourdontube意為“彈簧管”。例如：Instrument

ismade

upof

control

indication

system,

whichare

lead

by

separate

bourdon

tube.

該儀表由控制系統(tǒng)和指示系統(tǒng)兩部分組成，分別由獨立的彈簧管帶動。UnitNotestotheText句中“Thegreatesterrorintheuseoftheglassther-mometer”是主語，itisoftennotreadinplace是that引導的表語從句。Error在句中意為“誤差”。例如：Ithastheadvantagetoeliminatethe

error.它有消除穩(wěn)態(tài)誤差的優(yōu)點。2、Thegreatesterrorintheuseoftheglassther-mometeristhatitisoftennotreadinplace.UnitNotestotheText句中while引導狀語從句theyareactuallyincontactwiththemediumbeingmeasured.incontactwith在句中意為“接觸”。例如：Whathappenswhensodiumis

in

contact

withchlorine.

當鈉，氯離子接觸會發(fā)生什么。3、Readglassthermometerswhiletheyareactuallyincontactwiththemediumbeingmeasured.UnitNotestotheText裝有內(nèi)蓋的熱保護器可以直接對壓縮機殼體的表面溫度做出反應。reactto意為“對…作出反應”。例如：Everyone

makesmistakes,

but

the

real

test

is

how

you

react

to

that.

每個人都會犯錯，而真正的考驗是你對錯誤的反應如何。Skin在句中意為“外殼”。例如：thewoodskinofaboat船的木制外殼4、Dome-mountedthermalprotectorsactuallyreacttothesurfacetemperatureofthecompressorskin.UnitNotestotheText熱電偶很容易固定到管子內(nèi)壁去測量內(nèi)部溫度。句中ontothesurfaceofpipes和tochecktheinsidetemperature分別作為狀語。tape意為“用帶子捆扎，粘貼”。例如：Itapedthebaseofthefeatherontothevelvet.我用膠帶把羽毛的根部粘到天鵝絨上。5、Thermocouplesareeasilytapedontothesurfaceofpipesto